Theory PTA

theory PTA
  imports "library/Lib"
begin

section ‹Bisimulation on a Relation› text_raw ‹\label{thm:bisim}›

definition rel_set_strong :: "('a ⇒ 'b ⇒ bool) ⇒ 'a set ⇒ 'b set ⇒ bool"
  where "rel_set_strong R A B ⟷ (∀x y. R x y ⟶ (x ∈ A ⟷ y ∈ B))"

lemma T_eq_rel_half[consumes 4, case_names prob sets cont]:
  fixes R :: "'s ⇒ 't ⇒ bool" and f :: "'s ⇒ 't" and S :: "'s set"
  assumes R_def: "⋀s t. R s t ⟷ (s ∈ S ∧ f s = t)"
  assumes A[measurable]: "A ∈ sets (stream_space (count_space UNIV))"
    and B[measurable]: "B ∈ sets (stream_space (count_space UNIV))"
    and AB: "rel_set_strong (stream_all2 R) A B" and KL: "rel_fun R (rel_pmf R) K L" and xy: "R x y"
  shows "MC_syntax.T K x A = MC_syntax.T L y B"
proof -
  interpret K: MC_syntax K by unfold_locales
  interpret L: MC_syntax L by unfold_locales

  have "x ∈ S" using ‹R x y› by (auto simp: R_def)

  define g where "g t = (SOME s. R s t)" for t
  have measurable_g: "g ∈ count_space UNIV →⇩M count_space UNIV" by auto
  have g: "R i j ⟹ R (g j) j" for i j
    unfolding g_def by (rule someI)
  
  have K_subset: "x ∈ S ⟹ K x ⊆ S" for x
    using KL[THEN rel_funD, of x "f x", THEN rel_pmf_imp_rel_set] by (auto simp: rel_set_def R_def)

  have in_S: "AE ω in K.T x. ω ∈ streams S"
    using K.AE_T_enabled
  proof eventually_elim 
    case (elim ω) with ‹x ∈ S› show ?case
      apply (coinduction arbitrary: x ω)
      subgoal for x ω using K_subset by (cases ω) (auto simp: K.enabled_Stream)
      done
  qed

  have L_eq: "L y = map_pmf f (K x)" if xy: "R x y" for x y
  proof -
    have "rel_pmf (λx y. x = y) (map_pmf f (K x)) (L y)"
      using KL[THEN rel_funD, OF xy] by (auto intro: pmf.rel_mono_strong simp: R_def pmf.rel_map)
    then show ?thesis unfolding pmf.rel_eq by simp
  qed

  let ?D = "λx. distr (K.T x) K.S (smap f)"
  have prob_space_D: "?D x ∈ space (prob_algebra K.S)" for x 
    by (auto simp: space_prob_algebra K.T.prob_space_distr)

  have D_eq_D: "?D x = ?D x'" if "R x y" "R x' y" for x x' y
  proof (rule stream_space_eq_sstart)
    define A where "A = K.acc `` {x, x'}"
    have x_A: "x ∈ A" "x' ∈ A" by (auto simp: A_def)
    let ?Ω = "f ` A"
    show "countable ?Ω"
      unfolding A_def by (intro countable_image K.countable_acc) auto
    show "prob_space (?D x)" "prob_space (?D x')" by (auto intro!: K.T.prob_space_distr)
    show "sets (?D x) = sets L.S" "sets (?D x') = sets L.S" by auto
    have AE_streams: "AE x in ?D x''. x ∈ streams ?Ω" if "x'' ∈ A" for x''
      apply (simp add: space_stream_space streams_sets AE_distr_iff)
      using K.AE_T_reachable[of x''] unfolding alw_HLD_iff_streams
    proof eventually_elim
      fix s assume "s ∈ streams (K.acc `` {x''})"
      moreover have "K.acc `` {x''} ⊆ A"
        using ‹x'' ∈ A› by (auto simp: A_def Image_def intro: rtrancl_trans)
      ultimately show "smap f s ∈ streams (f ` A)"
        by (auto intro: smap_streams)
    qed
    with x_A show "AE x in ?D x'. x ∈ streams ?Ω" "AE x in ?D x. x ∈ streams ?Ω"
      by auto
    from ‹x ∈ A› ‹x' ∈ A› that show "?D x (sstart (f ` A) xs) = ?D x' (sstart (f ` A) xs)" for xs
    proof (induction xs arbitrary: x x' y)
      case Nil
      moreover have "?D x (streams (f ` A)) = 1" if "x ∈ A" for x
        using AE_streams[of x] that
        by (intro prob_space.emeasure_eq_1_AE[OF K.T.prob_space_distr]) (auto simp: streams_sets)
      ultimately show ?case by simp
    next
      case (Cons z zs x x' y)
      have "rel_pmf (R OO R¯¯) (K x) (K x')"
        using KL[THEN rel_funD, OF Cons(4)] KL[THEN rel_funD, OF Cons(5)]
        unfolding pmf.rel_compp pmf.rel_flip by auto
      then obtain p :: "('s × 's) pmf" where p: "⋀a b. (a, b) ∈ p ⟹ (R OO R¯¯) a b" and
        eq: "map_pmf fst p = K x" "map_pmf snd p = K x'"
        by (auto simp: pmf.in_rel)
      let ?S = "stream_space (count_space UNIV)"
      have *: "(##) y -` smap f -` sstart (f ` A) (z # zs) = (if f y = z then smap f -` sstart (f ` A) zs else {})" for y z zs
        by auto
      have **: "?D x (sstart (f ` A) (z # zs)) = (∫⇧+ y'. (if f y' = z then ?D y' (sstart (f ` A) zs) else 0) ∂K x)" for x
        apply (simp add: emeasure_distr)
        apply (subst K.T_eq_bind)
        apply (subst emeasure_bind[where N="?S"])
           apply simp
          apply (rule measurable_distr2[where M="?S"])
           apply measurable
        apply (intro nn_integral_cong_AE AE_pmfI)
        apply (auto simp add: emeasure_distr)
        apply (simp_all add: * space_stream_space)
        done
      have fst_A: "fst ab ∈ A" if "ab ∈ p" for ab
      proof -
        have "fst ab ∈ K x" using ‹ab ∈ p› set_map_pmf [of fst p] by (auto simp: eq)
        with ‹x ∈ A› show "fst ab ∈ A"
          by (auto simp: A_def intro: rtrancl.rtrancl_into_rtrancl)
      qed
      have snd_A: "snd ab ∈ A" if "ab ∈ p" for ab
      proof -
        have "snd ab ∈ K x'" using ‹ab ∈ p› set_map_pmf [of snd p] by (auto simp: eq)
        with ‹x' ∈ A› show "snd ab ∈ A"
          by (auto simp: A_def intro: rtrancl.rtrancl_into_rtrancl)
      qed
      show ?case
        unfolding ** eq[symmetric] nn_integral_map_pmf
        apply (intro nn_integral_cong_AE AE_pmfI)
        subgoal for ab using p[of "fst ab" "snd ab"] by (auto simp: R_def intro!: Cons(1) fst_A snd_A)
        done
    qed
  qed

  have L_eq_D: "L.T y = ?D x"
    using ‹R x y›
  proof (coinduction arbitrary: x y rule: L.T_coinduct)
    case (cont x y)
    then have Kx_Ly: "rel_pmf R (K x) (L y)"
      by (rule KL[THEN rel_funD])
    then have *: "y' ∈ L y ⟹ ∃x'∈K x. R x' y'" for y'
      by (auto dest!: rel_pmf_imp_rel_set simp: rel_set_def)
    have **: "y' ∈ L y ⟹ R (g y') y'" for y'
      using *[of y'] unfolding g_def by (auto intro: someI)

    have D_SCons_eq_D_D: "distr (K.T i) K.S (λx. z ## smap f x) = distr (?D i) K.S (λx. z ## x)" for i z
      by (subst distr_distr) (auto simp: comp_def)
    have D_eq_D_gi: "?D i = ?D (g (f i))" if i: "i ∈ K x" for i
    proof -
      obtain j where "j ∈ L y" "R i j" "f i = j"
        using Kx_Ly i by (force dest!: rel_pmf_imp_rel_set simp: rel_set_def R_def)
      then show ?thesis
        by (auto intro!: D_eq_D[OF ‹R i j›] g)
    qed

    have ***: "?D x = measure_pmf (L y) ⤜ (λy. distr (?D (g y)) K.S ((##) y))"
      apply (subst K.T_eq_bind)
      apply (subst distr_bind[of _ _ K.S])
         apply (rule measurable_distr2[of _  _ "K.S"])
          apply (simp_all add: Pi_iff)
      apply (simp add: distr_distr comp_def L_eq[OF cont] map_pmf_rep_eq)
      apply (subst bind_distr[where K=K.S])
         apply measurable []
        apply (rule measurable_distr2[of _  _ "K.S"])
        apply measurable []
        apply (rule measurable_compose[OF measurable_g])
        apply measurable []
       apply simp
      apply (rule bind_measure_pmf_cong[where N="K.S"])
        apply (auto simp: space_subprob_algebra space_stream_space intro!: K.T.subprob_space_distr)
        unfolding D_SCons_eq_D_D D_eq_D_gi ..
    show ?case
      by (intro exI[of _ "λt. distr (K.T (g t)) (stream_space (count_space UNIV)) (smap f)"])
         (auto simp add: K.T.prob_space_distr *** dest: **)
  qed (auto intro: K.T.prob_space_distr)

  have "stream_all2 R s t ⟷ (s ∈ streams S ∧ smap f s = t)" for s t 
  proof safe
    show "stream_all2 R s t ⟹ s ∈ streams S"
      apply (coinduction arbitrary: s t)
      subgoal for s t by (cases s; cases t) (auto simp: R_def)
      done
    show "stream_all2 R s t ⟹ smap f s = t"
      apply (coinduction arbitrary: s t rule: stream.coinduct)
      subgoal for s t by (cases s; cases t) (auto simp: R_def)
      done
  qed (auto intro!: stream.rel_refl_strong simp: stream.rel_map R_def streams_iff_sset)
  then have "ω ∈ streams S ⟹ ω ∈ A ⟷ smap f ω ∈ B" for ω
    using AB by (auto simp: rel_set_strong_def)
  with in_S have "K.T x A = K.T x (smap f -` B ∩ space (K.T x))"
    by (auto intro!: emeasure_eq_AE streams_sets)
  also have "… = (distr (K.T x) K.S (smap f)) B"
    by (intro emeasure_distr[symmetric]) auto
  also have "… = (L.T y) B" unfolding L_eq_D ..
  finally show ?thesis .
qed

no_notation ccval ("⦃_⦄" [100])

hide_const succ


section ‹Additional Facts on Regions›

(* XXX Move this to a theory on Timed Automata *)
declare reset_set11[simp] reset_set1[simp]

text ‹
  Defining the closest successor of a region. Only exists if at least one interval is upper-bounded.
›

abbreviation is_upper_right where
  "is_upper_right R ≡ (∀ t ≥ 0. ∀ u ∈ R. u ⊕ t ∈ R)"

(* XXX Remove old successor definition *)
definition
  "succ ℛ R ≡
  if is_upper_right R then R else
  (THE R'. R' ≠ R ∧ R' ∈ Succ ℛ R ∧ (∀ u ∈ R. ∀ t ≥ 0. (u ⊕ t) ∉ R ⟶ (∃ t' ≤ t. (u ⊕ t') ∈ R' ∧ 0 ≤ t')))"

lemma region_continuous:
  assumes "valid_region X k I r"
  defines R: "R ≡ region X I r"
  assumes between: "0 ≤ t1" "t1 ≤ t2"
  assumes elem: "u ∈ R" "u ⊕ t2 ∈ R"
  shows "u ⊕ t1 ∈ R"
unfolding R
proof
  from ‹0 ≤ t1› ‹u ∈ R› show "∀x∈X. 0 ≤ (u ⊕ t1) x" by (auto simp: R cval_add_def)

  have "intv_elem x (u ⊕ t1) (I x)" if "x ∈ X" for x
  proof -
    from elem that have "intv_elem x u (I x)" "intv_elem x (u ⊕ t2) (I x)" by (auto simp: R)
    with between show ?thesis by (cases "I x", auto simp: cval_add_def)
  qed
  then show "∀ x ∈ X. intv_elem x (u ⊕ t1) (I x)" by blast

  let ?X⇩0 = "{x ∈ X. ∃d. I x = Intv d}"
  show "?X⇩0 = ?X⇩0" ..

  from elem have "∀ x ∈ ?X⇩0. ∀ y ∈ ?X⇩0. (x, y) ∈ r ⟷ frac (u x) ≤ frac (u y)" by (auto simp: R)
  moreover
  { fix x y c d assume A: "x ∈ X" "y ∈ X" "I x = Intv c" "I y = Intv d"
    from A elem between have *:
      "c < u x" "u x < c + 1" "c < u x + t1" "u x + t1 < c + 1"
    by (fastforce simp: cval_add_def R)+
    moreover from A(2,4) elem between have **:
      "d < u y" "u y < d + 1" "d < u y + t1" "u y + t1 < d + 1"
    by (fastforce simp: cval_add_def R)+
    ultimately have "u x = c + frac (u x)" "u y = d + frac (u y)" using nat_intv_frac_decomp by auto
    then have
      "frac (u x + t1) = frac (u x) + t1" "frac (u y + t1) = frac (u y) + t1"
    using *(3,4) **(3,4) nat_intv_frac_decomp by force+
    then have
      "frac (u x) ≤ frac (u y) ⟷ frac ((u ⊕ t1) x) ≤ frac ((u ⊕ t1) y)"
    by (auto simp: cval_add_def)
  }
  ultimately show
    "∀ x ∈ ?X⇩0. ∀ y ∈ ?X⇩0. (x, y) ∈ r ⟷ frac ((u ⊕ t1) x) ≤ frac ((u ⊕ t1) y)"
  by (auto simp: cval_add_def)
qed

lemma upper_right_eq:
  assumes "finite X" "valid_region X k I r"
  shows "(∀ x ∈ X. isGreater (I x)) ⟷ is_upper_right (region X I r)"
using assms
proof (safe, goal_cases)
  case (1 t u)
  then show ?case
    by - (standard, force simp: cval_add_def)+
next
  case (2 x)
  (* XXX Does this lemma actually need the finiteness assumption? *)
  from region_not_empty[OF assms] obtain u where u: "u ∈ region X I r" ..
  moreover have "(1 :: real) ≥ 0" by auto
  ultimately have "(u ⊕ 1) ∈ region X I r" using 2 by auto
  with ‹x ∈ X› u have "intv_elem x u (I x)" "intv_elem x (u ⊕ 1) (I x)" by auto
  then show ?case by (cases "I x", auto simp: cval_add_def)
qed

lemma bounded_region:
  assumes "finite X" "valid_region X k I r"
  defines R: "R ≡ region X I r"
  assumes "¬ is_upper_right R" "u ∈ R"
  shows "u ⊕ 1 ∉ R"
proof -
  from upper_right_eq[OF assms(1,2)] assms(4) obtain x where x:
    "x ∈ X" "¬ isGreater (I x)"
  by (auto simp: R)
  with assms have "intv_elem x u (I x)" by auto
  with x(2) have "¬ intv_elem x (u ⊕ 1) (I x)" by (cases "I x", auto simp: cval_add_def)
  with x(1) assms show ?thesis by auto
qed

(* XXX Remove Caml case *)
context AlphaClosure
begin

(* XXX Clean *)
no_notation Regions_Beta.part ("[_]⇩_" [61,61] 61)

lemma succ_ex:
  assumes "R ∈ ℛ"
  shows "succ ℛ R ∈ ℛ" (is "?G1") and "succ ℛ R ∈ Succ ℛ R" (is "?G2")
  and "∀ u ∈ R. ∀ t ≥ 0. (u ⊕ t) ∉ R ⟶ (∃ t' ≤ t. (u ⊕ t') ∈ succ ℛ R ∧ 0 ≤ t')" (is "?G3")
proof -
  from ‹R ∈ ℛ› obtain I r where R: "R = region X I r" "valid_region X k I r"
    unfolding ℛ_def by auto
  from region_not_empty[OF finite] R obtain u where u: "u ∈ R"
    by blast
  let ?Z = "{x ∈ X . ∃ c. I x = Const c}"
  let ?succ =
    "λ R'. R' ≠ R ∧ R' ∈ Succ ℛ R
     ∧ (∀ u ∈ R. ∀ t ≥ 0. (u ⊕ t) ∉ R ⟶ (∃ t' ≤ t. (u ⊕ t') ∈ R' ∧ 0 ≤ t'))"
  consider (upper_right) "∀ x ∈ X. isGreater (I x)" | (intv) "∃ x ∈ X. ∃ d. I x = Intv d ∧ ?Z = {}"
         | (const) "?Z ≠ {}"
  apply (cases "∀ x ∈ X. isGreater (I x)")
   apply fast
  apply (cases "?Z = {}")
   apply safe
   apply (rename_tac x)
   apply (case_tac "I x")
  by auto
  then have "?G1 ∧ ?G2 ∧ ?G3"
  proof cases
    case const
    with upper_right_eq[OF finite R(2)] have "¬ is_upper_right R" by (auto simp: R(1))
    from closest_prestable_1(1,2)[OF const finite R(2)] closest_valid_1[OF const finite R(2)] R(1)
    obtain R' where R':
      "∀ u ∈ R. ∀ t>0. ∃t'≤t. (u ⊕ t') ∈ R' ∧ t' ≥ 0" "R' ∈ ℛ" "∀ u ∈ R'. ∀ t≥0. (u ⊕ t) ∉ R"
    unfolding ℛ_def by auto
    with region_not_empty[OF finite] obtain u' where "u' ∈ R'" unfolding ℛ_def by blast
    with R'(3) have neq: "R' ≠ R" by (fastforce simp: cval_add_def)
    obtain t:: real where "t > 0" by (auto intro: that[of 1])
    with R'(1,2) ‹u ∈ R› obtain t where "t ≥ 0" "u ⊕ t ∈ R'" by auto
    with ‹R ∈ ℛ› ‹R' ∈ ℛ› ‹u ∈ R› have "R' ∈ Succ ℛ R" by (intro SuccI3)
    moreover have "(∀ u ∈ R. ∀ t ≥ 0. (u ⊕ t) ∉ R ⟶ (∃ t' ≤ t. (u ⊕ t') ∈ R' ∧ 0 ≤ t'))"
      using R'(1) unfolding cval_add_def
      apply clarsimp
      subgoal for u t
        by (cases "t = 0") auto
      done
    ultimately have *: "?succ R'" using neq by auto
    have "succ ℛ R = R'" unfolding succ_def
    proof (simp add: ‹¬ is_upper_right R›, intro the_equality, rule *, goal_cases)
      case prems: (1 R'')
      from prems obtain t' u' where R'':
        "R'' ∈ ℛ" "R'' ≠ R" "t' ≥ 0" "R'' = [u' ⊕ t']⇩ℛ" "u' ∈ R"
      using R'(1) by fastforce
      from this(1) obtain I r where R''2:
        "R'' = region X I r" "valid_region X k I r"
        by (auto simp: ℛ_def)
      from R'' have "u' ⊕ t' ∉ R" using assms region_unique_spec by blast
      with * ‹t' ≥ 0› ‹u' ∈ R› obtain t'' where t'': "t'' ≤ t'" "u' ⊕ t'' ∈ R'" "t'' ≥ 0" by auto
      from this(2) neq have "u' ⊕ t'' ∉ R" using R'(2) assms region_unique_spec by auto
      with t'' prems ‹u' ∈ R› obtain t''' where t''':
        "t''' ≤ t''" "u' ⊕ t''' ∈ R''" "t''' ≥ 0"
      by auto
      with region_continuous[OF R''2(2) _ _ t'''(2)[unfolded R''2(1)], of "t'' - t'''" "t' - t'''"]
           t'' R'' regions_closed'_spec[OF ‹R ∈ ℛ› R''(5,3)]
      have "u' ⊕ t'' ∈ R''" by (auto simp: R''2 cval_add_def)
      with t''(2) show ?case using R''(1) R'(2) region_unique_spec by blast
    qed
    with R' * show ?thesis by auto
  next
    case intv
    then have *: "∀x∈X. ¬ Regions.isConst (I x)" by auto
    let ?X⇩0 = "{x ∈ X. isIntv (I x)}"
    let ?M = "{x ∈ ?X⇩0. ∀y∈?X⇩0. (x, y) ∈ r ⟶ (y, x) ∈ r}"
    from intv obtain x c where x: "x ∈ X" "¬ isGreater (I x)" and c: "I x = Intv c" by auto
    with ‹x ∈ X› have "?X⇩0 ≠ {}" by auto
    have "?X⇩0 = {x ∈ X. ∃d. I x = Intv d}" by auto
    with R(2) have r: "total_on ?X⇩0 r" "trans r" by auto
    from total_finite_trans_max[OF ‹?X⇩0 ≠ {}› _ this] finite
    obtain x' where x': "x' ∈ ?X⇩0" "∀ y ∈ ?X⇩0. x' ≠ y ⟶ (y, x') ∈ r" by fastforce
    from this(2) have "∀y∈?X⇩0. (x', y) ∈ r ⟶ (y, x') ∈ r" by auto
    with x'(1) have **: "?M ≠ {}" by fastforce
    with upper_right_eq[OF finite R(2)] have "¬ is_upper_right R" by (auto simp: R(1))
    from closest_prestable_2(1,2)[OF * finite R(2) **] closest_valid_2[OF * finite R(2) **] R(1)
    obtain R' where R':
      "(∀ u ∈ R. ∀ t ≥ 0. (u ⊕ t) ∉ R ⟶ (∃ t' ≤ t. (u ⊕ t') ∈ R' ∧ 0 ≤ t'))" "R' ∈ ℛ"
      "∀ u ∈ R'. ∀ t≥0. (u ⊕ t) ∉ R"
    unfolding ℛ_def by auto
    with region_not_empty[OF finite] obtain u' where "u' ∈ R'" unfolding ℛ_def by blast
    with R'(3) have neq: "R' ≠ R" by (fastforce simp: cval_add_def)
    from bounded_region[OF finite R(2), folded R(1), OF ‹¬ is_upper_right R› u] have
      "u ⊕ (1 :: t) ∉ R" "(1 :: t) ≥ 0"
    by auto
    with R'(1) u obtain t' where "t' ≤ (1 :: t)" "(u ⊕ t') ∈ R'" "0 ≤ t'" by fastforce
    with ‹R ∈ ℛ› ‹R' ∈ ℛ› ‹u ∈ R› have "R' ∈ Succ ℛ R" by (intro SuccI3)
    with R'(1) neq have *: "?succ R'" by auto
    have "succ ℛ R = R'" unfolding succ_def
    proof (simp add: ‹¬ is_upper_right R›, intro the_equality, rule *, goal_cases)
      case prems: (1 R'')
      from prems obtain t' u' where R'':
        "R'' ∈ ℛ" "R'' ≠ R" "t' ≥ 0" "R'' = [u' ⊕ t']⇩ℛ" "u' ∈ R"
      using R'(1) by fastforce
      from this(1) obtain I r where R''2:
        "R'' = region X I r" "valid_region X k I r"
      by (auto simp: ℛ_def)
      from R'' have "u' ⊕ t' ∉ R" using assms region_unique_spec by blast
      with * ‹t' ≥ 0› ‹u' ∈ R› obtain t'' where t'': "t'' ≤ t'" "u' ⊕ t'' ∈ R'" "t'' ≥ 0" by auto
      from this(2) neq have "u' ⊕ t'' ∉ R" using R'(2) assms region_unique_spec by auto
      with t'' prems ‹u' ∈ R› obtain t''' where t''':
        "t''' ≤ t''" "u' ⊕ t''' ∈ R''" "t''' ≥ 0"
      by auto
      with region_continuous[OF R''2(2) _ _ t'''(2)[unfolded R''2(1)], of "t'' - t'''" "t' - t'''"]
           t'' R'' regions_closed'_spec[OF ‹R ∈ ℛ› R''(5,3)]
      have "u' ⊕ t'' ∈ R''" by (auto simp: cval_add_def R''2)
      with t''(2) show ?case using R''(1) R'(2) region_unique_spec by blast
    qed
    with R' * show ?thesis by auto
  next
    case upper_right
    with upper_right_eq[OF finite R(2)] have "succ ℛ R = R" by (auto simp: R succ_def)
    with ‹R ∈ ℛ› u show ?thesis by (fastforce simp: cval_add_def intro: SuccI3)
  qed
  then show ?G1 ?G2 ?G3 by auto
qed
      
lemma region_set'_closed:
  fixes d :: nat
  assumes "R ∈ ℛ" "d ≥ 0" "∀x∈set r. d ≤ k x" "set r ⊆ X"
  shows "region_set' R r d ∈ ℛ"
proof -
  from region_not_empty[OF finite] assms(1) obtain u where "u ∈ R" using ℛ_def by blast
  from region_set'_id[OF _ _  finite, of _ k, folded ℛ_def] assms this show ?thesis by fastforce
qed

(* XXX Move *)
lemma clock_set_cong[simp]:
  assumes "∀ c ∈ set r. u c = d"
  shows "[r → d]u = u"
proof standard
  fix c
  from assms show "([r → d]u) c = u c" by (cases "c ∈ set r"; auto)
qed

lemma region_reset_not_Succ:
  (* XXX Declare globally? *)
  notes regions_closed'_spec[intro]
  assumes "R ∈ ℛ" "set r ⊆ X"
  shows "region_set' R r 0 = R ∨ region_set' R r 0 ∉ Succ ℛ R" (is "?R = R ∨ _")
proof -
  from assms finite obtain u where "u ∈ R" by (meson Succ.cases succ_ex(2))
  with ‹R ∈ ℛ› have "u ∈ V" "[u]⇩ℛ = R" by (auto simp: region_unique_spec dest: region_V) 
  with region_set'_id[OF ‹R ∈ ℛ›[unfolded ℛ_def] ‹u ∈ R› finite] assms(2) have
    "?R = [[r→0]u]⇩ℛ"
  by (force simp: ℛ_def)
  show ?thesis
  proof (cases "∀ x ∈ set r. u x = 0")
    case True
    then have "[r→0]u = u" by simp
    with ‹?R = _› ‹_ = R› have "?R = R" by (force simp: ℛ_def)
    then show ?thesis ..
  next
    case False
    then obtain x where x: "x ∈ set r" "u x ≠ 0" by auto
    { assume "?R ∈ Succ ℛ R"
      with ‹u ∈ R› ‹R ∈ ℛ› obtain t where
        "t ≥ 0" "[u ⊕ t]⇩ℛ = ?R" "?R ∈ ℛ"
      by (meson Succ.cases set_of_regions_spec)
      with ‹u ∈ R› assms(1) have "u ⊕ t ∈ ?R" by blast
      moreover from ‹?R = _› ‹u ∈ R› have "[r→0]u ∈ ?R" by (fastforce simp: region_set'_def)
      moreover from x ‹t ≥ 0› ‹u ∈ V› assms have "(u ⊕ t) x > 0" by (force simp: cval_add_def V_def)
      moreover from x have "([r→0]u) x = 0" by auto
      ultimately have False using ‹?R ∈ ℛ› x(1) by (fastforce simp: region_set'_def)
    }
    then show ?thesis by auto
  qed
qed

end (* Alpha Closure global *)

subsection ‹Justifying Timed Until vs ∗‹suntil››

(* XXX Move *)
lemma guard_continuous:
  assumes "u ⊢ g" "u ⊕ t ⊢ g" "0 ≤ (t'::'t::time)" "t' ≤ t"
  shows "u ⊕ t' ⊢ g"
  using assms
  by (induction g;
      auto 4 3
        simp: cval_add_def order_le_less_subst2 order_subst2 add_increasing2
        intro: less_le_trans
     )

(* XXX Move *)
(*
lemma guard_continuous:
  assumes "u ⊢ g" "u ⊕ t ⊢ g" "0 ≤ t'" "t' ≤ t"
  shows "u ⊕ t' ⊢ g"
  using assms by (auto 4 4 intro: atomic_guard_continuous simp: list_all_iff)
*)

section ‹Definition and Semantics›

subsection ‹Syntactic Definition›

text ‹
  We do not include:
  ▪ a labelling function, as we will assume that atomic propositions are simply sets of states
  ▪ a fixed set of locations or clocks, as we will implicitly derive it from the set of transitions
  ▪ start or end locations, as we will primarily study reachability
›

type_synonym
  ('c, 't, 's) transition = "'s * ('c, 't) cconstraint * ('c set * 's) pmf"

type_synonym
  ('c, 't, 's) pta = "('c, 't, 's) transition set * ('c, 't, 's) invassn"

definition
  edges :: "('c, 't, 's) transition ⇒ ('s * ('c, 't) cconstraint * ('c set * 's) pmf * 'c set * 's) set"
where
  "edges ≡ λ (l, g, p). {(l, g, p, X, l') | X l'. (X, l') ∈ set_pmf p}"

definition
  "Edges A ≡ ⋃ {edges t | t. t ∈ fst A}"

definition
  trans_of :: "('c, 't, 's) pta ⇒ ('c, 't, 's) transition set"
where
  "trans_of ≡ fst"

definition
  inv_of  :: "('c, 'time, 's) pta ⇒ ('c, 'time, 's) invassn"
where
  "inv_of ≡ snd"

no_notation transition ("_ ⊢ _ ⟶⇗_,_,_⇖ _" [61,61,61,61,61,61] 61)

abbreviation transition ::
  "('c, 'time, 's) pta ⇒ 's ⇒ ('c, 'time) cconstraint ⇒ ('c set * 's) pmf ⇒ 'c set ⇒ 's ⇒ bool"
("_ ⊢ _ ⟶⇗_,_,_⇖ _" [61,61,61,61,61,61] 61) where
  "(A ⊢ l ⟶⇗g,p,X⇖ l') ≡ (l, g, p, X, l') ∈ Edges A"

definition
  locations  :: "('c, 't, 's) pta ⇒ 's set"
where
  "locations A ≡ (fst ` Edges A) ∪ ((snd o snd o snd o snd) ` Edges A)"


subsubsection ‹Collecting Information About Clocks›

(* XXX Remove sort constraints *)

definition collect_clkt :: "('c, 't::time, 's) transition set ⇒ ('c *'t) set"
where
  "collect_clkt S = ⋃ {collect_clock_pairs (fst (snd t)) | t . t ∈ S}"

definition collect_clki :: "('c, 't :: time, 's) invassn ⇒ ('c *'t) set"
where
  "collect_clki I = ⋃ {collect_clock_pairs (I x) | x. True}"

definition clkp_set :: "('c, 't :: time, 's) pta ⇒ ('c * 't) set"
where
  "clkp_set A = collect_clki (inv_of A) ∪ collect_clkt (trans_of A)"

definition collect_clkvt :: "('c, 't :: time, 's) pta ⇒ 'c set"
where
  "collect_clkvt A = ⋃ ((fst o snd o snd o snd) ` Edges A)"

abbreviation clocks where "clocks A ≡ fst ` clkp_set A ∪ collect_clkvt A"

definition valid_abstraction
where
  "valid_abstraction A X k ≡
  (∀(x,m) ∈ clkp_set A. m ≤ k x ∧ x ∈ X ∧ m ∈ ℕ) ∧ collect_clkvt A ⊆ X ∧ finite X"

lemma valid_abstractionD[dest]:
  assumes "valid_abstraction A X k"
  shows "(∀(x,m) ∈ clkp_set A. m ≤ k x ∧ x ∈ X ∧ m ∈ ℕ)" "collect_clkvt A ⊆ X" "finite X"
using assms unfolding valid_abstraction_def by auto

lemma valid_abstractionI[intro]:
  assumes "(∀(x,m) ∈ clkp_set A. m ≤ k x ∧ x ∈ X ∧ m ∈ ℕ)" "collect_clkvt A ⊆ X" "finite X"
  shows "valid_abstraction A X k"
using assms unfolding valid_abstraction_def by auto

subsection ‹Operational Semantics as an MDP›

abbreviation (input) clock_set_set :: "'c set ⇒ 't::time ⇒ ('c,'t) cval ⇒ ('c,'t) cval"
("[_:=_]_" [65,65,65] 65)
where
  "[X:=t]u ≡ clock_set (SOME r. set r = X) t u"

term region_set'

abbreviation region_set_set :: "'c set ⇒ 't::time ⇒ ('c,'t) zone ⇒ ('c,'t) zone"
("[_::=_]_" [65,65,65] 65)
where
  "[X::=t]R ≡ region_set' R (SOME r. set r = X) t"

no_notation zone_set ("_⇘_ → 0⇙" [71] 71)

abbreviation zone_set_set :: "('c, 't::time) zone ⇒ 'c set ⇒ ('c, 't) zone"
("_⇘_ → 0⇙" [71] 71)
where
  "Z⇘X → 0⇙ ≡ zone_set Z (SOME r. set r = X)"

abbreviation (input) ccval ("⦃_⦄" [100]) where "ccval cc ≡ {v. v ⊢ cc}"

locale Probabilistic_Timed_Automaton =
  fixes A :: "('c, 't :: time, 's) pta"
  assumes admissible_targets:
    "(l, g, μ) ∈ trans_of A ⟹ (X, l') ∈ μ ⟹ ⦃g⦄⇘X → 0⇙ ⊆ ⦃inv_of A l'⦄"
    "(l, g, μ) ∈ trans_of A ⟹ (X, l') ∈ μ ⟹ X ⊆ clocks A"
  ― ‹Not necessarily what we want to have›
begin

subsection ‹Syntactic Definition› text_raw ‹ \label{sem:mdp} ›

definition "L = locations A"

definition "𝒳 = clocks A"

definition "S ≡ {(l, u) . l ∈ L ∧ (∀ x ∈ 𝒳. u x ≥ 0) ∧ u ⊢ inv_of A l}"

inductive_set
  K :: "('s * ('c, 't) cval) ⇒ ('s * ('c, 't) cval) pmf set" for st :: "('s * ('c, 't) cval)"
where
  ― ‹Passage of time› delay:
  "st ∈ S ⟹ st = (l, u) ⟹ t ≥ 0 ⟹ u ⊕ t ⊢ inv_of A l ⟹ return_pmf (l, u ⊕ t) ∈ K st" |
  ― ‹Discrete transitions› action:
  "st ∈ S ⟹ st = (l, u) ⟹ (l, g, μ) ∈ trans_of A ⟹ u ⊢ g
  ⟹ map_pmf (λ (X, l). (l, ([X := 0]u))) μ ∈ K st" |
  ― ‹Self loops -- Note that this does not assume ‹st ∈ S›› loop:
  "return_pmf st ∈ K st"

declare K.intros[intro]

sublocale MDP: Markov_Decision_Process K by (standard, auto)

end (* Probabilistic Timed Automaton *)

section ‹Constructing the Corresponding Finite MDP on Regions›

locale Probabilistic_Timed_Automaton_Regions =
  Probabilistic_Timed_Automaton A + Regions 𝒳
  for A :: "('c, t, 's) pta" +
  ― ‹The following are necessary to obtain a ‹finite› MDP›
  assumes finite: "finite 𝒳" "finite L" "finite (trans_of A)"
  assumes not_trivial: "∃ l ∈ L. ∃ u ∈ V. u ⊢ inv_of A l"
  assumes valid: "valid_abstraction A 𝒳 k"
begin

lemmas finite_ℛ = finite_ℛ[OF finite(1), of k, folded ℛ_def]


subsection ‹Syntactic Definition› text_raw ‹ \label{sem:mdprg} ›

definition "𝒮 ≡ {(l, R) . l ∈ L ∧ R ∈ ℛ ∧ R ⊆ {u. u ⊢ inv_of A l}}"

(* XXX Move definition of V somewhere else *)
lemma S_alt_def: "S = {(l, u) . l ∈ L ∧ u ∈ V ∧ u ⊢ inv_of A l}" unfolding V_def S_def by auto

text ‹
  Note how we relax the definition to allow more transitions in the first case.
  To obtain a more compact MDP the commented out version can be used an proved equivalent.
›

inductive_set
 𝒦 :: "('s * ('c, t) cval set) ⇒ ('s * ('c, t) cval set) pmf set" for st :: "('s * ('c, t) cval set)"
where
  (* 
  -- "Passage of time" delay:
  "st ∈ 𝒮 ⟹ st = (l,R) ⟹ succ ℛ R ⊆ ⦃inv_of A l⦄ ⟹ return_pmf (l, succ ℛ R) ∈ 𝒦 st" |
  *)
   ― ‹Passage of time› delay:
  "st ∈ 𝒮 ⟹ st = (l,R) ⟹ R' ∈ Succ ℛ R ⟹ R' ⊆ ⦃inv_of A l⦄ ⟹ return_pmf (l, R') ∈ 𝒦 st" |
  ― ‹Discrete transitions› action:
  "st ∈ 𝒮 ⟹ st = (l, R ) ⟹ (l, g, μ) ∈ trans_of A ⟹ R ⊆ ⦃g⦄
  ⟹ map_pmf (λ (X, l). (l, region_set' R (SOME r. set r = X) 0)) μ ∈ 𝒦 st" |
  ― ‹Self loops -- Note that this does not assume ‹st ∈ 𝒮›› loop:
  "return_pmf st ∈ 𝒦 st"

lemmas [intro] = 𝒦.intros


subsection ‹Many Closure Properties›

lemma transition_def:
  "(A ⊢ l ⟶⇗g,μ,X⇖ l') = ((l, g, μ) ∈ trans_of A ∧ (X, l') ∈ μ)"
  unfolding Edges_def edges_def trans_of_def by auto

lemma transitionI[intro]:
  "A ⊢ l ⟶⇗g,μ,X⇖ l'" if "(l, g, μ) ∈ trans_of A" "(X, l') ∈ μ"
  using that unfolding transition_def ..

lemma transitionD[dest]:
  "(l, g, μ) ∈ trans_of A" "(X, l') ∈ μ" if "A ⊢ l ⟶⇗g,μ,X⇖ l'"
  using that unfolding transition_def by auto

lemma bex_Edges:
  "(∃ x ∈ Edges A. P x) = (∃ l g μ X l'. A ⊢ l ⟶⇗g,μ,X⇖ l' ∧ P (l, g, μ, X, l'))"
  by fastforce

(* XXX Move *)
lemma L_trans[intro]:
  assumes "(l, g, μ) ∈ trans_of A" "(X, l') ∈ μ"
  shows "l ∈ L" "l' ∈ L"
  using assms unfolding L_def locations_def by (auto simp: image_iff bex_Edges transition_def)

lemma transition_𝒳:
  "X ⊆ 𝒳" if "A ⊢ l ⟶⇗g,μ,X⇖ l'"
  using that unfolding 𝒳_def collect_clkvt_def clkp_set_def by auto

lemma admissible_targets_alt:
  "A ⊢ l ⟶⇗g,μ,X⇖ l' ⟹ ⦃g⦄⇘X → 0⇙ ⊆ ⦃inv_of A l'⦄"
  "A ⊢ l ⟶⇗g,μ,X⇖ l' ⟹ X ⊆ clocks A"
  by (intro admissible_targets; blast)+

lemma V_reset_closed[intro]:
  assumes "u ∈ V"
  shows "[r → (d::nat)]u ∈ V"
using assms unfolding V_def
  apply safe
  subgoal for x
    by (cases "x ∈ set r"; auto)
  done

lemmas V_reset_closed'[intro] = V_reset_closed[of _ _ 0, simplified]

lemma regions_part_ex[intro]:
  assumes "u ∈ V"
  shows "u ∈ [u]⇩ℛ" "[u]⇩ℛ ∈ ℛ"
proof -
  from assms regions_partition[OF meta_eq_to_obj_eq[OF ℛ_def]] have
    "∃!R. R ∈ ℛ ∧ u ∈ R"
    unfolding V_def by auto
  then show "[u]⇩ℛ ∈ ℛ" "u ∈ [u]⇩ℛ"
    using alpha_interp.region_unique_spec by auto
qed

lemma rep_ℛ_ex[intro]:
  assumes "R ∈ ℛ"
  shows "(SOME u. u ∈ R) ∈ R"
proof -
  from assms region_not_empty[OF finite(1)] have "∃ u. u ∈ R" unfolding ℛ_def by auto
  then show ?thesis ..
qed

lemma V_nn_closed[intro]:
  "u ∈ V ⟹ t ≥ 0 ⟹ u ⊕ t ∈ V"
unfolding V_def cval_add_def by auto

lemma K_S_closed[intro]:
  assumes "μ ∈ K s" "s' ∈ μ" "s ∈ S"
  shows "s' ∈ S"
  using assms
  by (cases rule: K.cases, auto simp: S_alt_def dest: admissible_targets[unfolded zone_set_def])

lemma S_V[intro]:
  "(l, u) ∈ S ⟹ u ∈ V"
unfolding S_alt_def by auto

lemma L_V[intro]:
  "(l, u) ∈ S ⟹ l ∈ L"
unfolding S_def by auto

lemma 𝒮_V[intro]:
  "(l, R) ∈ 𝒮 ⟹ R ∈ ℛ"
unfolding 𝒮_def by auto

lemma admissible_targets':
  assumes "(l, g, μ) ∈ trans_of A" "(X, l') ∈ μ" "R ⊆ ⦃g⦄"
  shows "region_set' R (SOME r. set r = X) 0 ⊆ ⦃inv_of A l'⦄"
using admissible_targets(1)[OF assms(1,2)] assms(3) unfolding region_set'_def zone_set_def by auto


subsection ‹The Region Graph is a Finite MDP›

lemma 𝒮_finite:
  "finite 𝒮"
using finite finite_ℛ unfolding 𝒮_def by auto

lemma 𝒦_finite:
  "finite (𝒦 st)"
proof -
  let ?B1 = "{(R', l, R). st ∈ 𝒮 ∧ st = (l, R) ∧ R' ∈ Succ ℛ R ∧ R' ⊆ ⦃inv_of A l⦄}"
  let ?S1 = "(λ(R', l, R). return_pmf (l, R')) ` ?B1"
  let ?S1 = "{return_pmf (l, R') | R' l R. st ∈ 𝒮 ∧ st = (l, R) ∧ R' ∈ Succ ℛ R ∧ R' ⊆ ⦃inv_of A l⦄}"
  let ?S2 = "{map_pmf (λ (X, l). (l, region_set' R (SOME r. set r = X) 0)) μ
             | R μ. ∃ l g. st ∈ 𝒮 ∧ st = (l, R ) ∧ (l, g, μ) ∈ trans_of A ∧ R ⊆ ⦃g⦄}"
  have "?B1 ⊆ {(R', l, R). R' ∈ ℛ ∧ (l, R) ∈ 𝒮 }" unfolding 𝒮_def by auto
  with 𝒮_finite finite_ℛ have "finite ?B1" by - (rule finite_subset, auto)
  moreover have "?S1 = (λ(R', l, R). return_pmf (l, R')) ` ?B1" by (auto simp: image_def)
  ultimately have *: "finite ?S1" by auto
  have "{μ. ∃l g. (l, g, μ) ∈ PTA.trans_of A} = ((λ (l, g, μ). μ) ` PTA.trans_of A)" by force
  with finite(3) finite_ℛ have "finite {(R, μ). ∃ l g. R ∈ ℛ ∧ (l, g, μ) ∈ trans_of A}" by auto
  moreover have
    "{(R, μ). ∃ l g. st ∈ 𝒮 ∧ st = (l, R ) ∧ (l, g, μ) ∈ trans_of A ∧ R ⊆ ⦃g⦄} ⊆ …"
  unfolding 𝒮_def by fastforce
  ultimately have **:
    "finite {(R, μ). ∃ l g. st ∈ 𝒮 ∧ st = (l, R ) ∧ (l, g, μ) ∈ trans_of A ∧ R ⊆ ⦃g⦄}"
  unfolding 𝒮_def by (blast intro: finite_subset)
  then have "finite ?S2" unfolding 𝒮_def by auto
  have "𝒦 st = ?S1 ∪ ?S2 ∪ {return_pmf st}" by (safe, cases rule: 𝒦.cases, auto)
  with * ** show ?thesis by auto
qed

(* XXX Obsolete in here, move to Regions *)
lemma ℛ_not_empty:
  "ℛ ≠ {}"
proof -
  let ?r = "{}"
  let ?I = "λ c. Const 0"
  let ?R = "region 𝒳 ?I ?r"
  have "valid_region 𝒳 k ?I ?r"
  proof
    show "{} = {x ∈ 𝒳. ∃d. Const 0 = Intv d}" by auto
    show "refl_on {} {}" and "trans {}" and "total_on {} {}" unfolding trans_def by auto
    show "∀x ∈ 𝒳. Regions.valid_intv (k x) (Const 0)" by auto
  qed
  then have "?R ∈ ℛ" unfolding ℛ_def by auto
  then show "ℛ ≠ {}" by blast
qed

lemma 𝒮_not_empty:
  "𝒮 ≠ {}"
proof -
  from not_trivial obtain l u where st: "l ∈ L" "u ∈ V" "u ⊢ inv_of A l" by blast
  then obtain R where R: "R ∈ ℛ" "u ∈ R" using ℛ_V by auto
  from valid have
    "∀(x, m)∈collect_clock_pairs (inv_of A l). m ≤ real (k x) ∧ x ∈ 𝒳 ∧ m ∈ ℕ"
  by (fastforce simp: clkp_set_def collect_clki_def)
  from ccompatible[OF this, folded ℛ_def] R st(3) have
    "R ⊆ ⦃inv_of A l⦄"
  unfolding ccompatible_def ccval_def by auto
  with st(1) R(1) show ?thesis unfolding 𝒮_def by auto
qed

lemma 𝒦_𝒮_closed:
  assumes "s ∈ 𝒮"
  shows "(⋃D∈𝒦 s. set_pmf D) ⊆ 𝒮"
proof (safe, cases rule: 𝒦.cases, blast, goal_cases)
  case (1 x a b l R)
  then show ?case unfolding 𝒮_def by (auto intro: alpha_interp.succ_ex(1))
next
  case (3 a b x)
  with ‹s ∈ 𝒮› show ?case by auto
next
  case prems: (2 l' R' p l R g μ)
  then obtain X where *: "(X, l') ∈ set_pmf μ" "R' = region_set' R (SOME r. set r = X) 0" by auto
  
  show ?case unfolding 𝒮_def
  proof safe
    from *(1) have "(l, g, μ, X, l') ∈ edges (l,g, μ)" unfolding edges_def by auto
    with prems(6) have "(l, g, μ, X, l') ∈ Edges A" unfolding Edges_def trans_of_def by auto
    then show "l' ∈ L" unfolding L_def locations_def by force

    show "u ⊢ inv_of A l'" if "u ∈ R'" for u
    using admissible_targets'[OF prems(6) *(1) prems(7)] *(2) that by auto    
    
    from admissible_targets(2)[OF prems(6) *(1)] have "X ⊆ 𝒳" unfolding 𝒳_def by auto
    with finite(1) have "finite X" by (blast intro: finite_subset)
    then obtain r where "set r = X" using finite_list by auto
    then have "set (SOME r. set r = X) = X" by (rule someI)
    with ‹X ⊆ 𝒳› have "set (SOME r. set r = X) ⊆ 𝒳" by auto
    with alpha_interp.region_set'_closed[of R 0 "SOME r. set r = X"] prems(4,5) *(2)
    show "R' ∈ ℛ" unfolding 𝒮_def 𝒳_def by auto
  qed
qed

sublocale R_G: Finite_Markov_Decision_Process 𝒦 𝒮
by (standard, auto simp: 𝒮_finite 𝒮_not_empty 𝒦_finite 𝒦_𝒮_closed)

lemmas 𝒦_𝒮_closed'[intro] = R_G.set_pmf_closed


section ‹Relating the MDPs›

subsection ‹Translating From K to ‹𝒦››

(* XXX Clean this for regular automata too *)
(* Assumption of valid too strong? i.e. do not need l ∈ L here *)
lemma ccompatible_inv:
  shows "ccompatible ℛ (inv_of A l)"
proof -
  from valid have
    "∀(x, m)∈collect_clock_pairs (inv_of A l). m ≤ real (k x) ∧ x ∈ 𝒳 ∧ m ∈ ℕ"
  unfolding valid_abstraction_def clkp_set_def collect_clki_def by auto
  with ccompatible[of _ k 𝒳, folded ℛ_def] show ?thesis by auto
qed

lemma ccompatible_guard:
  assumes "(l, g, μ) ∈ trans_of A"
  shows "ccompatible ℛ g"
proof -
  from assms valid have
    "∀(x, m)∈collect_clock_pairs g. m ≤ real (k x) ∧ x ∈ 𝒳 ∧ m ∈ ℕ"
  unfolding valid_abstraction_def clkp_set_def collect_clkt_def trans_of_def by fastforce
  with assms ccompatible[of _ k 𝒳, folded ℛ_def] show ?thesis by auto
qed

lemmas ccompatible_def = ccompatible_def[unfolded ccval_def]

lemma region_set'_eq:
  fixes X :: "'c set"
  assumes "R ∈ ℛ" "u ∈ R"
      and "A ⊢ l ⟶⇗g,μ,X⇖ l'"
  shows
    "[[X:=0]u]⇩ℛ = region_set' R (SOME r. set r = X) 0" "[[X:=0]u]⇩ℛ ∈ ℛ" "[X:=0]u ∈ [[X:=0]u]⇩ℛ"
proof -
  let ?r = "(SOME r. set r = X)"
  from admissible_targets_alt[OF assms(3)] 𝒳_def finite have "finite X"
    by (auto intro: finite_subset)
  then obtain r where "set r = X" using finite_list by blast
  then have "set ?r = X" by (intro someI)
  with valid assms(3) have "set ?r ⊆ 𝒳"
    by (simp add: transition_𝒳)
  from region_set'_id[of _ 𝒳 k, folded ℛ_def, OF assms(1,2) finite(1) _ _ this]
  show
    "[[X:=0]u]⇩ℛ = region_set' R (SOME r. set r = X) 0" "[[X:=0]u]⇩ℛ ∈ ℛ" "[X:=0]u ∈ [[X:=0]u]⇩ℛ"
  by force+
qed

lemma regions_part_ex_reset:
  assumes "u ∈ V"
  shows  "[r → (d::nat)]u ∈ [[r → d]u]⇩ℛ" "[[r → d]u]⇩ℛ ∈ ℛ"
using assms by auto

lemma reset_sets_all_equiv:
  assumes "u ∈ V" "u' ∈ [[r → (d :: nat)]u]⇩ℛ" "x ∈ set r" "set r ⊆ 𝒳" "d ≤ k x"
  shows "u' x = d"
proof -
  from assms(1) have u: "[r → d]u ∈ [[r → d]u]⇩ℛ" "[[r → d]u]⇩ℛ ∈ ℛ" by auto
  then obtain I ρ where I: "[[r → d]u]⇩ℛ = region 𝒳 I ρ" "valid_region 𝒳 k I ρ"
    by (auto simp: ℛ_def)
  with u(1) assms(3-) have "intv_elem x ([r → d]u) (I x)" "valid_intv (k x) (I x)" by fastforce+
  moreover from assms have "([r → d]u) x = d" by simp
  ultimately have "I x = Const d" using assms(5) by (cases "I x") auto
  moreover from I assms(2-) have "intv_elem x u' (I x)" by fastforce
  ultimately show "u' x = d" by auto
qed

lemma reset_eq:
  assumes "u ∈ V" "([[r → 0]u]⇩ℛ) = ([[r' → 0]u]⇩ℛ)" "set r ⊆ 𝒳" "set r' ⊆ 𝒳"
  shows "[r → 0]u = [r' → 0]u" using assms 
proof -
  have *: "u' x = 0" if "u' ∈ [[r → 0]u]⇩ℛ" "x ∈ set r" for u' x
  using reset_sets_all_equiv[of u u' r 0 x] that assms by auto
  have "u' x = 0" if "u' ∈ [[r' → 0]u]⇩ℛ" "x ∈ set r'" for u' x 
  using reset_sets_all_equiv[of u u' r' 0 x] that assms by auto
  from regions_part_ex_reset[OF assms(1), of _ 0] assms(2) have **:
    "([r' → 0]u) ∈ [[r → 0]u]⇩ℛ" "([r → 0]u) ∈ [[r → 0]u]⇩ℛ" "[[r → 0]u]⇩ℛ ∈ ℛ"
  by auto
  have "(([r → 0]u) x) = (([r' → 0]u) x)" for x
  proof (cases "x ∈ set r")
    case True
    then have "([r → 0]u) x = 0" by simp
    moreover from * ** True have "([r' → 0]u) x = 0" by auto
    ultimately show ?thesis ..
  next
    case False
    then have id: "([r→0]u) x = u x" by simp
    show ?thesis
    proof (cases "x ∈ set r'")
      case True
      then have reset: "([r' → 0]u) x = 0" by simp
      show ?thesis
      proof (cases "x ∈ 𝒳")
        case True
        from **(3) obtain I ρ where
          "([([r → 0]u)]⇩ℛ) = Regions.region 𝒳 I ρ" "Regions.valid_region 𝒳 k I ρ"
        by (auto simp: ℛ_def)
        with ** ‹x ∈ 𝒳› have ***:
          "intv_elem x ([r' → 0]u) (I x)" "intv_elem x ([r → 0]u) (I x)"
        by auto
        with reset have "I x = Const 0" by (cases "I x", auto)
        with ***(2) have "([r → 0]u) x = 0" by auto
        with reset show ?thesis by auto
      next
        case False
        with assms(3-) have "x ∉ set r" "x ∉ set r'" by auto
        then show ?thesis by simp
      qed
    next
      case False
      then have reset: "([r' → 0]u) x = u x" by simp
      with id show ?thesis by simp
    qed
  qed
  then show ?thesis ..
qed

lemma admissible_targets_clocks:
  assumes "(l, g, μ) ∈ trans_of A" "(X, l') ∈ μ"
  shows "X ⊆ 𝒳" "set (SOME r. set r = X) ⊆ 𝒳"
proof -
  from admissible_targets(2)[OF assms] finite have
    "finite X" "X ⊆ 𝒳"
  by (auto intro: finite_subset simp: 𝒳_def)
  then obtain r where "set r = X" using finite_list by blast
  with ‹X ⊆ 𝒳› show "X ⊆ 𝒳" "set (SOME r. set r = X) ⊆ 𝒳"
    by (metis (mono_tags, lifting) someI_ex)+
qed

lemma
  "rel_pmf (λ a b. f a = b) μ (map_pmf f μ)"
by (subst pmf.rel_map(2)) (rule rel_pmf_reflI, auto)

lemma K_pmf_rel:
  defines "f ≡ λ (l, u). (l, [u]⇩ℛ)"
  shows "rel_pmf (λ (l, u) st. (l, [u]⇩ℛ) = st) μ (map_pmf f μ)" unfolding f_def
by (subst pmf.rel_map(2)) (rule rel_pmf_reflI, auto)

lemma 𝒦_pmf_rel:
  assumes A: "μ ∈ 𝒦 (l, R)"
  defines "f ≡ λ (l, u). (l, SOME u. u ∈ R)"
  shows "rel_pmf (λ (l, u) st. (l, SOME u. u ∈ R) = st) μ (map_pmf f μ)" unfolding f_def
by (subst pmf.rel_map(2)) (rule rel_pmf_reflI, auto)

lemma K_elem_abs_inj:
  assumes A: "μ ∈ K (l, u)"
  defines "f ≡ λ (l, u). (l, [u]⇩ℛ)"
  shows "inj_on f μ"
proof -
  have "(l1, u1) = (l2, u2)"
    if id: "(l1, [u1]⇩ℛ) = (l2, [u2]⇩ℛ)" and elem: "(l1, u1) ∈ μ" "(l2, u2) ∈ μ" for l1 l2 u1 u2
  proof -
    from id have [simp]: "l2 = l1" by auto
    from A
    show ?thesis
    proof (cases, safe, goal_cases)
      case (4 _ _ τ μ')
      from ‹μ = _› elem obtain X1 X2 where
        "u1 = [(SOME r. set r = X1)→0]u" "(X1, l1) ∈ μ'"
        "u2 = [(SOME r. set r = X2)→0]u" "(X2, l1) ∈ μ'"
      by auto
      with ‹_ ∈ trans_of _› admissible_targets_clocks have
        "set (SOME r. set r = X1) ⊆ 𝒳" "set (SOME r. set r = X2) ⊆ 𝒳"
      by auto
      with id ‹u1 = _› ‹u2 = _› reset_eq[of u] ‹_ ∈ S› show ?case by (auto simp: S_def V_def)
    qed (-, insert elem, simp)+
  qed
  then show ?thesis unfolding f_def inj_on_def by auto
qed

lemma K_elem_repr_inj:
  notes alpha_interp.valid_regions_distinct_spec[intro] (* XXX Declare somewhere else *)
  assumes A: "μ ∈ 𝒦 (l, R)"
  defines "f ≡ λ (l, R). (l, SOME u. u ∈ R)"
  shows "inj_on f μ"
proof -
  have "(l1, R1) = (l2, R2)"
    if id: "(l1, SOME u. u ∈ R1) = (l2, SOME u. u ∈ R2)" and elem: "(l1, R1) ∈ μ" "(l2, R2) ∈ μ"
    for l1 l2 R1 R2
  proof -
    let ?r1 = "SOME u. u ∈ R1" and ?r2 = "SOME u. u ∈ R2"
    from id have [simp]: "l2 = l1" "?r2 = ?r1" by auto
    { fix g μ' x
      assume "(l, R) ∈ 𝒮" "(l, g, μ') ∈ PTA.trans_of A" "R ⊆ {v. v ⊢ g}"
         and "μ = map_pmf (λ(X, l). (l, region_set' R (SOME r. set r = X) 0)) μ'"
      from ‹μ = _› elem obtain X1 X2 where
        "R1 = region_set' R (SOME r. set r = X1) 0" "(X1, l1) ∈ μ'"
        "R2 = region_set' R (SOME r. set r = X2) 0" "(X2, l1) ∈ μ'"
      by auto
      with ‹_ ∈ trans_of _› admissible_targets_clocks have
        "set (SOME r. set r = X1) ⊆ 𝒳" "set (SOME r. set r = X2) ⊆ 𝒳"
      by auto
      with alpha_interp.region_set'_closed[of _ 0] ‹R1 = _› ‹R2 = _› ‹_ ∈ 𝒮› have
        "R1 ∈ ℛ" "R2 ∈ ℛ"
      unfolding 𝒮_def by auto
      with region_not_empty[OF finite(1)] have
        "R1 ≠ {}" "R2 ≠ {}" "∃u. u ∈ R1" "∃u. u ∈ R2"
      by (auto simp: ℛ_def)
      from someI_ex[OF this(3)] someI_ex[OF this(4)] have "?r1 ∈ R1" "?r1 ∈ R2" by simp+
      with ‹R1 ∈ ℛ› ‹R2 ∈ ℛ› have "R1 = R2" ..
    }
    from A elem this show ?thesis by (cases, auto)
  qed
  then show ?thesis unfolding f_def inj_on_def by auto
qed

lemma K_elem_pmf_map_abs:
  assumes A: "μ ∈ K (l, u)" "(l', u') ∈ μ"
  defines "f ≡ λ (l, u). (l, [u]⇩ℛ)"
  shows "pmf (map_pmf f μ) (f (l', u')) = pmf μ (l', u')"
using A unfolding f_def by (blast intro: pmf_map_inj K_elem_abs_inj)

lemma K_elem_pmf_map_repr:
  assumes A: "μ ∈ 𝒦 (l, R)" "(l', R') ∈ μ"
  defines "f ≡ λ (l, R). (l, SOME u. u ∈ R)"
  shows "pmf (map_pmf f μ) (f (l', R')) = pmf μ (l', R')"
using A unfolding f_def by (blast intro: pmf_map_inj K_elem_repr_inj)



definition transp :: "('s * ('c, t) cval ⇒ bool) ⇒ 's * ('c, t) cval set ⇒ bool" where
  "transp φ ≡ λ (l, R). ∀ u ∈ R. φ (l, u)"

subsection ‹Translating Configurations›

subsubsection ‹States›

definition
  abss :: "'s * ('c, t) cval ⇒ 's * ('c, t) cval set"
where
  "abss ≡ λ (l, u). if u ∈ V then (l, [u]⇩ℛ) else (l, -V)"

definition
  reps :: "'s * ('c, t) cval set ⇒ 's * ('c, t) cval"
where
  "reps ≡ λ (l, R). if R ∈ ℛ then (l, SOME u. u ∈ R) else (l, λ_. -1)"

lemma 𝒮_reps_S[intro]:
  assumes "s ∈ 𝒮"
  shows "reps s ∈ S"
using assms ℛ_V unfolding S_def 𝒮_def reps_def V_def by force

lemma S_abss_𝒮[intro]:
  assumes "s ∈ S"
  shows "abss s ∈ 𝒮"
using assms ccompatible_inv unfolding 𝒮_def S_alt_def abss_def ccompatible_def by force

lemma 𝒮_abss_reps[simp]:
  "s ∈ 𝒮 ⟹ abss (reps s) = s"
using ℛ_V alpha_interp.region_unique_spec by (auto simp: S_def 𝒮_def reps_def abss_def; blast)

lemma map_pmf_abs_reps:
  assumes "s ∈ 𝒮" "μ ∈ 𝒦 s"
  shows "map_pmf abss (map_pmf reps μ) = μ"
proof -
  have "map_pmf abss (map_pmf reps μ) = map_pmf (abss o reps) μ" by (simp add: pmf.map_comp)
  also have "… = μ"
  proof (rule map_pmf_idI, safe, goal_cases)
    case prems: (1 l' R')
    with assms have "(l', R') ∈ 𝒮" "reps (l', R') ∈ S" by auto
    then show ?case by auto
  qed
  finally show ?thesis by auto
qed

lemma abss_reps_id:
  notes R_G.cfg_onD_state[simp del]
  assumes "s' ∈ 𝒮" "s ∈ set_pmf (action cfg)" "cfg ∈ R_G.cfg_on s'"
  shows "abss (reps s) = s"
proof -
  from assms have "s ∈ 𝒮" by auto
  then show ?thesis by auto
qed

lemma abss_S[intro]:
  assumes "(l, u) ∈ S"
  shows "abss (l, u) = (l, [u]⇩ℛ)"
using assms unfolding abss_def by auto

lemma reps_𝒮[intro]:
  assumes "(l, R) ∈ 𝒮"
  shows "reps (l, R) = (l, SOME u. u ∈ R)"
using assms unfolding reps_def by auto

lemma fst_abss:
  "fst (abss st) = fst st" for st
  by (cases st) (auto simp: abss_def)

lemma K_elem_abss_inj:
  assumes A: "μ ∈ K (l, u)" "(l, u) ∈ S"
  shows "inj_on abss μ"
proof -
  from assms have "abss s' = (λ (l, u). (l, [u]⇩ℛ)) s'" if "s' ∈ μ" for s'
  using that by (auto split: prod.split)
  from inj_on_cong[OF this] K_elem_abs_inj[OF A(1)] show ?thesis by force
qed

lemma 𝒦_elem_reps_inj:
  assumes A: "μ ∈ 𝒦 (l, R)" "(l, R) ∈ 𝒮"
  shows "inj_on reps μ"
proof -
  from assms have "reps s' = (λ (l, R). (l, SOME u. u ∈ R)) s'" if "s' ∈ μ" for s'
  using that by (auto split: prod.split)
  from inj_on_cong[OF this] K_elem_repr_inj[OF A(1)] show ?thesis by force
qed

lemma P_elem_pmf_map_abss:
  assumes A: "μ ∈ K (l, u)" "(l, u) ∈ S" "s' ∈ μ"
  shows "pmf (map_pmf abss μ) (abss s') = pmf μ s'"
using A by (blast intro: pmf_map_inj K_elem_abss_inj)

lemma 𝒦_elem_pmf_map_reps:
  assumes A: "μ ∈ 𝒦 (l, R)" "(l, R) ∈ 𝒮" "(l', R') ∈ μ"
  shows "pmf (map_pmf reps μ) (reps (l', R')) = pmf μ (l', R')"
using A by (blast intro: pmf_map_inj 𝒦_elem_reps_inj)

text ‹We need that ‹𝒳› is non-trivial here›
lemma not_𝒮_reps:
  "(l, R) ∉ 𝒮 ⟹ reps (l, R) ∉ S"
proof -
  assume "(l, R) ∉ 𝒮"
  let ?u = "SOME u. u ∈ R"
  have "¬ ?u ⊢ inv_of A l" if "R ∈ ℛ" "l ∈ L"
  proof -
    (* XXX Refactor -- doing that kind of proof at other places too *)
    from region_not_empty[OF finite(1)] ‹R ∈ ℛ› have "∃u. u ∈ R" by (auto simp: ℛ_def)
    from someI_ex[OF this] have "?u ∈ R" .
    moreover from ‹(l, R) ∉ 𝒮› that have "¬ R ⊆ ⦃inv_of A l⦄" by (auto simp: 𝒮_def)
    ultimately show ?thesis
      using ccompatible_inv[of l] ‹R ∈ ℛ› unfolding ccompatible_def by fastforce
  qed
  with non_empty ‹(l, R) ∉ 𝒮› show ?thesis unfolding 𝒮_def S_def reps_def by auto
qed

(* XXX Move up *)
lemma neq_V_not_region:
  "-V ∉ ℛ"
using ℛ_V rep_ℛ_ex by auto

lemma 𝒮_abss_S:
  "abss s ∈ 𝒮 ⟹ s ∈ S"
  unfolding abss_def 𝒮_def S_def
  apply safe
  subgoal for _ _ _ u
    by (cases "u ∈ V") auto
  subgoal for _ _ _ u
    using neq_V_not_region by (cases "u ∈ V", (auto simp: V_def; fail), auto)
  subgoal for l' y l u
    using neq_V_not_region by (cases "u ∈ V"; auto dest: regions_part_ex)
  done

lemma S_pred_stream_abss_𝒮:
  "pred_stream (λ s. s ∈ S) xs ⟷ pred_stream (λ s. s ∈ 𝒮) (smap abss xs)"
using S_abss_𝒮 𝒮_abss_S by (auto simp: stream.pred_set)


sublocale MDP: Markov_Decision_Process_Invariant K S by (standard, auto)

abbreviation (input) "valid_cfg ≡ MDP.valid_cfg"

lemma K_closed:
  "s ∈ S ⟹ (⋃D∈K s. set_pmf D) ⊆ S" 
  by auto


subsubsection ‹Intermezzo›

(* XXX Correct binding strength *)
abbreviation timed_bisim (infixr "~" 60) where
  "s ~ s' ≡ abss s = abss s'"

lemma bisim_loc_id[intro]:
  "(l, u) ~ (l', u') ⟹ l = l'"
unfolding abss_def by (cases "u ∈ V"; cases "u' ∈ V"; simp)

lemma bisim_val_id[intro]:
  "[u]⇩ℛ = [u']⇩ℛ" if "u ∈ V" "(l, u) ~ (l', u')"
proof -
  have "(l', - V) ≠ (l, [u]⇩ℛ)"
    using that by blast
  with that have "u' ∈ V"
    by (force simp: abss_def)
  with that show ?thesis
    by (simp add: abss_def)
qed

lemma bisim_symmetric:
  "(l, u) ~ (l', u') = (l', u') ~ (l, u)"
by (rule eq_commute)

lemma bisim_val_id2[intro]:
  "u' ∈ V ⟹ (l, u) ~ (l', u') ⟹ [u]⇩ℛ = [u']⇩ℛ"
 apply (subst (asm) eq_commute)
 apply (subst eq_commute)
 apply (rule bisim_val_id)
by auto

lemma K_bisim_unique:
  assumes "s ∈ S" "μ ∈ K s" "x ∈ μ" "x' ∈ μ" "x ~ x'"
  shows "x = x'"
using assms(2,1,3-)
proof (cases rule: K.cases)
  case prems: (action l u τ μ')
  with assms obtain l1 l2 X1 X2 where A:
    "(X1, l1) ∈ set_pmf μ'" "(X2, l2) ∈ set_pmf μ'"
    "x = (l1, [X1:=0]u)" "x' = (l2, [X2:=0]u)"
  by auto
  from ‹x ~ x'› A ‹s ∈ S› ‹s = (l, u)› have "[[X1:=0]u]⇩ℛ = [[X2:=0]u]⇩ℛ"
    using bisim_val_id[OF S_V] K_S_closed assms(2-4) by (auto intro!: bisim_val_id[OF S_V])
  then have "[X1:=0]u = [X2:=0]u"
    using A admissible_targets_clocks(2)[OF prems(4)] prems(2,3) by - (rule reset_eq, force)
  with A ‹x ~ x'› show ?thesis by auto
next
  case delay
  with assms(3-) show ?thesis by auto
next
  case loop
  with assms(3-) show ?thesis by auto
qed

subsubsection ‹Predicates›

definition absp where
  "absp φ ≡ φ o reps"

definition repp where
  "repp φ ≡ φ o absp"


subsubsection ‹Distributions›

definition
  abst :: "('s * ('c, t) cval) pmf ⇒ ('s * ('c, t) cval set) pmf"
where
  "abst = map_pmf abss"

lemma abss_𝒮D:
  assumes "abss s ∈ 𝒮"
  obtains l u where "s = (l, u)" "u ∈ [u]⇩ℛ" "[u]⇩ℛ ∈ ℛ"
proof -
  obtain l u where "s = (l, u)" by force
  moreover from 𝒮_abss_S[OF assms] have "s ∈ S" .
  ultimately have "abss s = (l, [u]⇩ℛ)" "u ∈ V" "u ∈ [u]⇩ℛ" "[u]⇩ℛ ∈ ℛ" by auto
  with ‹s = _› show ?thesis by (auto intro: that)
qed

lemma abss_𝒮D':
  assumes "abss s ∈ 𝒮" "abss s = (l, R)"
  obtains u where "s = (l, u)" "u ∈ [u]⇩ℛ" "[u]⇩ℛ ∈ ℛ" "R = [u]⇩ℛ"
proof -
  from abss_𝒮D[OF assms(1)] obtain l' u where u:
    "s = (l', u)" "u ∈ [u]⇩ℛ" "[u]⇩ℛ ∈ ℛ"
  by blast+
  with ℛ_V have "u ∈ V" by auto
  with ‹s = _› assms(2) have "l' = l" "R = [u]⇩ℛ" unfolding abss_def by auto
  with u show ?thesis by (auto intro: that)
qed

(*
definition
  rept :: "'s * ('c, t) cval ⇒ ('s * ('c, t) cval set) pmf ⇒ ('s * ('c, t) cval) pmf"
where
  "rept s μ_abs ≡ let (l, u) = s in
    if μ_abs = return_pmf (abss s)
    then if (∃ c ∈ 𝒳. ∃ d. u c = real d)
         then return_pmf s
         else return_pmf (l, u ⊕ 0.5)
    else SOME μ. μ ∈ K s ∧ abst μ = μ_abs"
*)

definition "infR R ≡ λ c. of_int ⌊(SOME u. u ∈ R) c⌋"

term "let a = 3 in b"

(* definition "shiftedR R ≡ let u = (SOME u. u ∈ R) in (u ⊕ max 0 (0.1 - Max {frac (u c) | c. c ∈ 𝒳}))" *)
(*
definition "delayedR R u ≡
  u ⊕ (
    let (I, r) = (SOME x. ∃ I r. x = (I, r) ∧ valid_region 𝒳 k I r ∧ R = region 𝒳 I r);
        m = Min {of_nat (intv_const (I c)) + 1 - u c | c. c ∈ 𝒳 ∧ isConst (I c)}
    in if m ≥ 1 then SOME t. u ⊕ t ∈ R else m / 2
  )"
*)

(*
definition "delayedR R u ≡
  u ⊕ (
    let (I, r) = (SOME x. ∃ I r. x = (I, r) ∧ valid_region 𝒳 k I r ∧ R = region 𝒳 I r);
        m = 1 - Max ({frac (u c) | c. c ∈ 𝒳 ∧ isIntv (I c) ∧ intv_const (I c) = 0} ∪ {0})
    in if m ≥ 1 then SOME t. u ⊕ t ∈ R else m / 2
  )"
*)

definition "delayedR R u ≡
  u ⊕ (
    let I = (SOME I. ∃ r. valid_region 𝒳 k I r ∧ R = region 𝒳 I r);
        m = 1 - Max ({frac (u c) | c. c ∈ 𝒳 ∧ isIntv (I c)} ∪ {0})
    in SOME t. u ⊕ t ∈ R ∧ t ≥ m / 2
  )"


(* XXX Move, generated by sledgehammer *)
lemma delayedR_correct_aux_aux:
  fixes c :: nat
  fixes a b :: real
  assumes "c < a" "a < Suc c" "b ≥ 0" "a + b < Suc c"
  shows "frac (a + b) = frac a + b"
(* Working alternative:
by (smt One_nat_def add.right_neutral add_Suc_right assms nat_intv_frac_decomp)
*)
proof -
  have f1: "a + b < real (c + 1)"
    using assms(4) by auto
  have f2: "⋀r ra. (r::real) + (- r + ra) = ra"
    by linarith
  have f3: "⋀r. (r::real) = - (- r)"
    by linarith
  have f4: "⋀r ra. - (r::real) + (ra + r) = ra"
    by linarith
  then have f5: "⋀r n. r + - frac r = real n ∨ ¬ r < real (n + 1) ∨ ¬ real n < r"
    using f2 by (metis nat_intv_frac_decomp)
  then have "frac a + real c = a"
    using f4 f3 by (metis One_nat_def add.right_neutral add_Suc_right assms(1) assms(2))
  then show ?thesis
    using f5 f1 assms(1) assms(3) by fastforce
qed

lemma delayedR_correct_aux:
  fixes I r
  defines "R ≡ region 𝒳 I r"
  assumes "u ∈ R" "valid_region 𝒳 k I r" "∀ c ∈ 𝒳. ¬ isConst (I c)"
          "∀ c ∈ 𝒳. isIntv (I c) ⟶ (u ⊕ t) c < intv_const (I c) + 1"
          "t ≥ 0"
  shows "u ⊕ t ∈ R" unfolding R_def
proof
  from assms have "R ∈ ℛ" unfolding ℛ_def by auto
  with ‹u ∈ R› ℛ_V have "u ∈ V" by auto
  with ‹t ≥ 0› show "∀x∈𝒳. 0 ≤ (u ⊕ t) x" unfolding V_def by (auto simp: cval_add_def)
  have "intv_elem x (u ⊕ t) (I x)" if "x ∈ 𝒳" for x
  proof (cases "I x")
    case Const
    with assms ‹x ∈ 𝒳› show ?thesis by auto
  next
    case (Intv c)
    with assms ‹x ∈ 𝒳› show ?thesis by (simp add: cval_add_def) (rule; force)
  next
    case (Greater c)
    with assms ‹x ∈ 𝒳› show ?thesis by (fastforce simp add: cval_add_def)
  qed
  then show "∀x∈𝒳. intv_elem x (u ⊕ t) (I x)" ..

  let ?X⇩0 = "{x ∈ 𝒳. ∃d. I x = Intv d}"
  show "?X⇩0 = ?X⇩0" by auto

  have "frac (u x + t) = frac (u x) + t" if "x ∈ ?X⇩0" for x
  proof -
    show ?thesis
      apply (rule delayedR_correct_aux_aux[where c = "intv_const (I x)"])
    using assms ‹x ∈ ?X⇩0› by (force simp add: cval_add_def)+
  qed
  then have "frac (u x) ≤ frac (u y) ⟷ frac (u x + t) ≤ frac (u y + t)" if "x ∈ ?X⇩0" "y ∈ ?X⇩0" for x y
  using that by auto
  with assms show
    "∀x∈?X⇩0. ∀y∈?X⇩0. ((x, y) ∈ r) = (frac ((u ⊕ t) x) ≤ frac ((u ⊕ t) y))"
  unfolding cval_add_def by auto
qed

lemma delayedR_correct_aux':
  fixes I r
  defines "R ≡ region 𝒳 I r"
  assumes "u ⊕ t1 ∈ R" "valid_region 𝒳 k I r" "∀ c ∈ 𝒳. ¬ isConst (I c)"
          "∀ c ∈ 𝒳. isIntv (I c) ⟶ (u ⊕ t2) c < intv_const (I c) + 1"
          "t1 ≤ t2"
  shows "u ⊕ t2 ∈ R"
proof -
  have "(u ⊕ t1) ⊕ (t2 - t1) ∈ R" unfolding R_def
    using assms by - (rule delayedR_correct_aux, auto simp: cval_add_def)
  then show "u ⊕ t2 ∈ R" by (simp add: cval_add_def)
qed


(* XXX Move to valid_regions_distinct *)
lemma valid_regions_intv_distinct:
  "valid_region X k I r ⟹ valid_region X k I' r' ⟹ u ∈ region X I r ⟹ u ∈ region X I' r'
  ⟹ x ∈ X ⟹ I x = I' x"
proof goal_cases
  case A: 1
  note x = ‹x ∈ X›
  with A have "valid_intv (k x) (I x)" by auto
  moreover from A(2) x have "valid_intv (k x) (I' x)" by auto
  moreover from A(3) x have "intv_elem x u (I x)" by auto
  moreover from A(4) x have "intv_elem x u (I' x)" by auto
  ultimately show "I x = I' x" using valid_intv_distinct by fastforce
qed

(* XXX Move *)
lemma delayedR_correct:
  fixes I r
  defines "R' ≡ region 𝒳 I r"
  assumes "u ∈ R" "R ∈ ℛ" "valid_region 𝒳 k I r" "∀ c ∈ 𝒳. ¬ isConst (I c)" "R' ∈ Succ ℛ R"
  shows
    "delayedR R' u ∈ R'"
    "∃ t ≥ 0. delayedR R' u = u ⊕ t
            ∧ t ≥ (1 - Max ({frac (u c) | c. c ∈ 𝒳 ∧ isIntv (I c)} ∪ {0})) / 2"
proof -
  let ?u = "SOME u. u ∈ R"
  let ?I = "SOME I. ∃ r. valid_region 𝒳 k I r ∧ R' = region 𝒳 I r"
  let ?S = "{frac (u c) | c. c ∈ 𝒳 ∧ isIntv (I c)}"
  let ?m = "1 - Max (?S ∪ {0})"
  let ?t = "SOME t. u ⊕ t ∈ R' ∧ t ≥ ?m / 2"
  have "Max (?S ∪ {0}) ≥ 0" "?m ≤ 1" using finite(1) by auto
  have "Max (?S ∪ {0}) ∈ ?S ∪ {0}" using finite(1) by - (rule Max_in; auto)
  with frac_lt_1 have "Max (?S ∪ {0}) ≤ 1" "?m ≥ 0" by auto
  from assms(3, 6) ‹u ∈ R› obtain t where t:
    "u ⊕ t ∈ R'" "t ≥ 0"
  by (metis alpha_interp.regions_closed'_spec alpha_interp.set_of_regions_spec)
  have I_cong: "∀ c ∈ 𝒳. I' c = I c" if "valid_region 𝒳 k I' r'" "R' = region 𝒳 I' r'" for I' r'
  using valid_regions_intv_distinct assms(4) t(1) that unfolding R'_def by auto
  have I_cong: "?I c = I c" if "c ∈ 𝒳" for c
  proof -
    from assms have
      "∃ r. valid_region 𝒳 k ?I r ∧ R' = region 𝒳 ?I r"
    by - (rule someI[where P = "λ I. ∃ r. valid_region 𝒳 k I r ∧ R' = region 𝒳 I r"]; auto)
    with I_cong that show ?thesis by auto
  qed
  then have "?S = {frac (u c) | c. c ∈ 𝒳 ∧ isIntv (?I c)}" by auto
  have upper_bound: "(u ⊕ ?m / 2) c < intv_const (I c) + 1" if "c ∈ 𝒳" "isIntv (I c)" for c
  proof (cases "u c > intv_const (I c)")
    case True
    from t that assms have "u c + t < intv_const (I c) + 1" unfolding cval_add_def by fastforce
    with ‹t ≥ 0› True have *: "intv_const (I c) < u c" "u c < intv_const (I c) + 1" by auto
    have "frac (u c) ≤ Max (?S ∪ {0})" using finite(1) that by - (rule Max_ge; auto)
    then have "?m ≤ 1 - frac (u c)" by auto
    then have "?m / 2 < 1 - frac (u c)" using * nat_intv_frac_decomp by fastforce 
    then have "(u ⊕ ?m / 2) c < u c + 1 - frac (u c)" unfolding cval_add_def by auto
    also from * have
      "… = intv_const (I c) + 1"
    using nat_intv_frac_decomp of_nat_1 of_nat_add by fastforce
    finally show ?thesis .
  next
    case False
    then have "u c ≤ intv_const (I c)" by auto
    moreover from ‹0 ≤ ?m› ‹?m ≤ 1› have "?m / 2 < 1" by auto
    ultimately have "u c + ?m / 2 < intv_const (I c) + 1" by linarith
    then show ?thesis by (simp add: cval_add_def)
  qed
  have "?t ≥ 0 ∧ u ⊕ ?t ∈ R' ∧ ?t ≥ ?m / 2"
  proof (cases "t ≥ ?m / 2")
    case True
    from ‹t ≥ ?m / 2› t ‹Max (?S ∪ {0}) ≤ 1› have "u ⊕ ?t ∈ R' ∧ ?t ≥ ?m / 2"
      by - (rule someI; auto)
    with ‹?m ≥ 0› show ?thesis by auto
  next
    case False
    have "u ⊕ ?m / 2 ∈ R'" unfolding R'_def
     apply (rule delayedR_correct_aux')
         apply (rule t[unfolded R'_def])
        apply (rule assms)+
    using upper_bound False by auto
    with ‹?m ≥ 0› show ?thesis by - (rule someI2; fastforce)
  qed
  then show "delayedR R' u ∈ R'" "∃t≥0. delayedR R' u = u ⊕ t ∧ t ≥ ?m / 2"
    by (auto simp: delayedR_def ‹?S = _›)
qed

definition
  rept :: "'s * ('c, t) cval ⇒ ('s * ('c, t) cval set) pmf ⇒ ('s * ('c, t) cval) pmf"
where
  "rept s μ_abs ≡ let (l, u) = s in
    if (∃ R'. (l, u) ∈ S ∧ μ_abs = return_pmf (l, R') ∧
        (([u]⇩ℛ = R' ∧ (∀ c ∈ 𝒳. u c > k c))))
    then return_pmf (l, u ⊕ 0.5)
    else if
      (∃ R'. (l, u) ∈ S ∧ μ_abs = return_pmf (l, R') ∧ R' ∈ Succ ℛ ([u]⇩ℛ) ∧ [u]⇩ℛ ≠ R'
           ∧ (∀ u ∈ R'. ∀ c ∈ 𝒳. ∄ d. d ≤ k c ∧  u c = real d))
    then return_pmf (l, delayedR (SOME R'. μ_abs = return_pmf (l, R')) u)
    else SOME μ. μ ∈ K s ∧ abst μ = μ_abs"

(* XXX Move *)
lemma 𝒮_L:
  "l ∈ L" if "(l, R) ∈ 𝒮"
  using that unfolding 𝒮_def by auto

lemma 𝒮_inv:
  "(l, R) ∈ 𝒮 ⟹ R ⊆ ⦃inv_of A l⦄"
  unfolding 𝒮_def by auto

lemma upper_right_closed:
  assumes "∀c∈𝒳. real (k c) < u c" "u ∈ R" "R ∈ ℛ" "t ≥ 0"
  shows "u ⊕ t ∈ R"
proof -
  from ‹R ∈ ℛ› obtain I r where R:
    "R = region 𝒳 I r" "valid_region 𝒳 k I r"
  unfolding ℛ_def by auto
  from assms ℛ_V have "u ∈ V" by auto
  from assms R have "∀ c ∈ 𝒳. I c = Greater (k c)" by safe (case_tac "I c"; fastforce)
  with R ‹u ∈ V› assms show
    "u ⊕ t ∈ R"
  unfolding V_def by safe (rule; force simp: cval_add_def)
qed

lemma S_I[intro]:
  "(l, u) ∈ S" if "l ∈ L" "u ∈ V" "u ⊢ inv_of A l"
  using that by (auto simp: S_def V_def)

lemma rept_ex:
  assumes "μ ∈ 𝒦 (abss s)"
  shows "rept s μ ∈ K s ∧ abst (rept s μ) = μ" using assms
proof cases
  case prems: (delay l R R')
  then have "R ∈ ℛ" by auto
  from prems(2) have "s ∈ S" by (auto intro: 𝒮_abss_S)
  from abss_𝒮D[OF prems(2)] obtain l' u' where "s = (l', u')" "u' ∈ [u']⇩ℛ"
    by metis
  with prems(3) have *: "s = (l, u') ∧ u' ∈ R"
   apply simp
   apply (subst (asm) abss_S[OF 𝒮_abss_S])
  using prems(2) by auto
  with prems(4) alpha_interp.set_of_regions_spec[OF ‹R ∈ ℛ›] obtain t where R':
    "t ≥ 0" "R' = [u' ⊕ t]⇩ℛ"
  by auto
  with ‹s ∈ S› * have "u' ⊕ t ∈ R'" "u' ⊕ t ∈ V" "l ∈ L" by auto
  with prems(5) have "(l, u' ⊕ t) ∈ S" unfolding S_def V_def by auto
  with ‹R' = [u' ⊕ t]⇩ℛ› have **: "abss (l, u' ⊕ t) = (l, R')" by (auto simp: abss_S)
  let ?μ = "return_pmf (l, u' ⊕ t)"
  have "?μ ∈ K s" using * ‹s ∈ S› ‹t ≥ 0› ‹u' ⊕ t ∈ R'› prems by blast
  moreover have "abst ?μ = μ" by (simp add: ** abst_def prems(1))
  moreover note default = calculation
  have "R' ∈ ℛ" using prems(4) by auto
  have R: "[u']⇩ℛ = R" by (simp add: * ‹R ∈ ℛ› alpha_interp.region_unique_spec) 
  from ‹R' ∈ ℛ› obtain I r where R':
    "R' = region 𝒳 I r" "valid_region 𝒳 k I r"
  unfolding ℛ_def by auto
  have "u' ∈ V" using * prems ℛ_V by force
  let ?μ' = "return_pmf (l, u' ⊕ 0.5)"
  have elapsed: "abst (return_pmf (l, u' ⊕ t)) = μ" "return_pmf (l, u' ⊕ t) ∈ K s"
    if "u' ⊕ t ∈ R'" "t ≥ 0" for t
  proof -
    let ?u = "u' ⊕ t" let ?μ' = "return_pmf (l, u' ⊕ t)"
    from ‹?u ∈ R'› ‹R' ∈ ℛ› ℛ_V have "?u ∈ V" by auto
    with ‹?u ∈ R'› ‹R' ∈ ℛ› have "[?u]⇩ℛ = R'" using alpha_interp.region_unique_spec by auto
    with ‹?u ∈ V› ‹?u ∈ R'› ‹l ∈ L› prems(4,5) have "abss (l, ?u) = (l, R')"
      by (subst abss_S) auto
    with prems(1) have "abst ?μ' = μ" by (auto simp: abst_def)
    moreover from * ‹?u ∈ R'› ‹s ∈ S› prems ‹t ≥ 0› have "?μ' ∈ K s" by auto
    ultimately show "abst ?μ' = μ" "?μ' ∈ K s" by auto
  qed
  show ?thesis
  proof (cases "R = R'")
    case T: True
    show ?thesis
    proof (cases "∀ c ∈ 𝒳. u' c > k c")
      case True
      with T * R prems(1,4) ‹s ∈ S› have
        "rept s μ = return_pmf (l, u' ⊕ 0.5)" (is "_ = ?μ")
      unfolding rept_def by auto
      from upper_right_closed[OF True] * ‹R' ∈ ℛ› T have "u' ⊕ 0.5 ∈ R'" by auto
      with elapsed ‹rept _ _ = _› show ?thesis by auto
    next
      case False
      with T * R prems(1) have
        "rept s μ = (SOME μ'. μ' ∈ K s ∧ abst μ' = μ)"
      unfolding rept_def by auto
      with default show ?thesis by simp (rule someI; auto)
    qed
  next
    case F: False
    show ?thesis
    proof (cases "∀ u ∈ R'. ∀ c ∈ 𝒳. ∄ d. d ≤ k c ∧ u c = real d")
      case False
      with F * R prems(1) have
        "rept s μ = (SOME μ'. μ' ∈ K s ∧ abst μ' = μ)"
      unfolding rept_def by auto
      with default show ?thesis by simp (rule someI; auto)
    next
      case True
      from True F * R prems(1,4) ‹s ∈ S› have
        "rept s μ = return_pmf (l, delayedR (SOME R'. μ = return_pmf (l, R')) u')"
        (is "_ = return_pmf (l, delayedR ?R u')")
      unfolding rept_def by auto
      let ?u = "delayedR ?R u'"
      from prems(1) have "μ = return_pmf (l, ?R)" by auto
      with prems(1) have "?R = R'" by auto
      moreover from R' True ‹_ ∈ R'› have "∀c∈𝒳. ¬ Regions.isConst (I c)" by fastforce
      moreover note delayedR_correct[of u' R I r] * ‹R ∈ ℛ› R' True ‹R' ∈ Succ ℛ R›
      ultimately obtain t where **: "delayedR R' u' ∈ R'" "t ≥ 0" "delayedR R' u' = u' ⊕ t" by auto
      moreover from ‹?R =_ ›‹rept _ _ = _› have "rept s μ = return_pmf (l, delayedR R' u')" by auto
      ultimately show ?thesis using elapsed by auto
    qed
  qed
next
  case prems: (action l R τ μ')
  from abss_𝒮D'[OF prems(2,3)] obtain u where u:
    "s = (l, u)" "u ∈ [u]⇩ℛ" "[u]⇩ℛ ∈ ℛ" "R = [u]⇩ℛ"
  by auto
  with ‹_ ∈ 𝒮› have "(l, u) ∈ S" by (auto intro: 𝒮_abss_S)
  let ?μ = "map_pmf (λ(X, l). (l, [X:=0]u)) μ'"
  from u prems have "?μ ∈ K s" by (fastforce intro: 𝒮_abss_S)
  moreover have "abst ?μ = μ" unfolding prems(1) abst_def
   proof (subst map_pmf_comp, rule pmf.map_cong, safe, goal_cases)
     case A: (1 X l')
     from u have "u ∈ V" using ℛ_V by auto
     then have "[X:=0]u ∈ V" by auto
     from prems(1) A
     have "(l', region_set' R (SOME r. set r = X) 0) ∈ μ" by auto
     from A prems R_G.K_closed ‹μ ∈ _› have
        "l' ∈ L" "region_set' R (SOME r. set r = X) 0 ⊆ ⦃inv_of A l'⦄"
     by (force dest: 𝒮_L 𝒮_inv)+
     with u have "[X:=0]u ⊢ inv_of A l'" unfolding region_set'_def by auto
     with ‹l' ∈ L› ‹[X:=0]u ∈ V› have "(l', [X:=0]u) ∈ S" unfolding S_def V_def by auto
     then have "abss (l', [X:=0]u) = (l', [[X:=0]u]⇩ℛ)" by auto
     also have
       "… = (l', region_set' R (SOME r. set r = X) 0)"
     using region_set'_eq(1)[unfolded transition_def] prems A u by force
    finally show ?case .
  qed
  ultimately have default: ?thesis if "rept s μ = (SOME μ'. μ' ∈ K s ∧ abst μ' = μ)" using that
  by simp (rule someI; auto)
  show ?thesis
  proof (cases "∃ R. μ = return_pmf (l, R)")
    case False
    with ‹s = (l, u)› have "rept s μ = (SOME μ'. μ' ∈ K s ∧ abst μ' = μ)" unfolding rept_def by auto
    with default show ?thesis by auto
  next
    case True
    then obtain R' where R': "μ = return_pmf (l, R')" by auto
    show ?thesis
    proof (cases "R = R'")
      case False
      from R' prems(1) have
        "∀ (X, l') ∈ μ'. (l', region_set' R (SOME r. set r = X) 0) = (l, R')"
      by (auto simp: map_pmf_eq_return_pmf_iff[of _ μ' "(l, R')"])
      then obtain X where
        "region_set' R (SOME r. set r = X) 0 = R'" "(X, l) ∈ μ'"
      using set_pmf_not_empty by force
      with prems(4) have "X ⊆ 𝒳" by (simp add: admissible_targets_clocks(1))
      moreover then have
        "set (SOME r. set r = X) = X"
      by - (rule someI_ex, metis finite_list finite(1) finite_subset)
      ultimately have "set (SOME r. set r = X) ⊆ 𝒳" by auto
      with alpha_interp.region_reset_not_Succ False ‹_ = R'› u(3,4) have "R' ∉ Succ ℛ R" by auto
      with ‹s = (l, u)› R' u(4) False have
        "rept s μ = (SOME μ'. μ' ∈ K s ∧ abst μ' = μ)"
      unfolding rept_def by auto
      with default show ?thesis by auto
    next
      case T: True
      show ?thesis
      proof (cases "∀c∈𝒳. real (k c) < u c")
        case False
        with T ‹s = (l, u)› R' u(4) have
          "rept s μ = (SOME μ'. μ' ∈ K s ∧ abst μ' = μ)"
        unfolding rept_def by auto
        with default show ?thesis by auto
      next
        case True
        with T ‹s = (l, u)› R' u(4) ‹(l, u) ∈ S› have
          "rept s μ = return_pmf (l, u ⊕ 0.5)"
        unfolding rept_def by auto
        from upper_right_closed[OF True] T u ℛ_V have "u ⊕ 0.5 ∈ R'" "u ⊕ 0.5 ∈ V" by force+
        moreover then have "[u ⊕ 0.5]⇩ℛ = R'"
          using T alpha_interp.region_unique_spec u(3,4) by blast 
        moreover note * = ‹rept _ _ = _› R' ‹abss s ∈ 𝒮› ‹abss s = _› prems(5)
        ultimately have "abst (rept s μ) = μ"
         apply (simp add: abst_def)
         apply (subst abss_S)
        by (auto simp: 𝒮_L S_def V_def T dest: 𝒮_inv)
        moreover from * ‹s = _› ‹(l, u) ∈ S› ‹_ ∈ R'› have
          "rept s μ ∈ K s"
         apply simp
         apply (rule K.delay)
        by (auto simp: T dest: 𝒮_inv)
        ultimately show ?thesis by auto
      qed
    qed
  qed
next
  case loop
  obtain l u where "s = (l, u)" by force
  show ?thesis
  proof (cases "s ∈ S")
    case T: True
    with ‹s = _› have *: "l ∈ L" "u ∈ [u]⇩ℛ" "[u]⇩ℛ ∈ ℛ" "abss s = (l, [u]⇩ℛ)" by auto
    then have "abss s = (l, [u]⇩ℛ)" by auto
    with ‹s ∈ S› S_abss_𝒮 have "(l, [u]⇩ℛ) ∈ 𝒮" by auto
    with 𝒮_inv have "[u]⇩ℛ ⊆ {u. u ⊢ inv_of A l}" by auto
    show ?thesis
    proof (cases "∀c∈𝒳. real (k c) < u c")
      case True
      with * ‹μ = _› ‹s = _› ‹s ∈ S› have
        "rept s μ = return_pmf (l, u ⊕ 0.5)"
      unfolding rept_def by auto
      from upper_right_closed[OF True] * have "u ⊕ 0.5 ∈ [u]⇩ℛ" by auto
      moreover with * ℛ_V have "u ⊕ 0.5 ∈ V" by auto
      moreover with calculation * alpha_interp.region_unique_spec have "[u ⊕ 0.5]⇩ℛ = [u]⇩ℛ" by blast
      moreover note * ‹rept _ _ = _› ‹s = _› T ‹μ = _› ‹(l, _) ∈ 𝒮› 𝒮_inv
      ultimately show ?thesis unfolding rept_def
       apply simp
       apply safe
        apply fastforce
       apply (simp add: abst_def)
       apply (subst abst_def abss_S)
      by fastforce+
    next
      case False
      with * ‹s = _› ‹μ = _› have
        "rept s μ = (SOME μ'. μ' ∈ K s ∧ abst μ' = μ)"
      unfolding rept_def by auto
      with ‹μ = _› show ?thesis by simp (rule someI[where x = "return_pmf s"], auto simp: abst_def)
    qed
  next
    case False
    with ‹s = _› ‹μ = _› have
        "rept s μ = (SOME μ'. μ' ∈ K s ∧ abst μ' = μ)"
    unfolding rept_def by auto
    with ‹μ = _› show ?thesis by simp (rule someI[where x = "return_pmf s"], auto simp: abst_def)
  qed
qed

lemmas rept_K[intro]       = rept_ex[THEN conjunct1]
lemmas abst_rept_id[simp]  = rept_ex[THEN conjunct2]

lemma abst_rept2:
  assumes "μ ∈ 𝒦 s" "s ∈ 𝒮"
  shows "abst (rept (reps s) μ) = μ"
using assms by auto

lemma rept_K2:
  assumes "μ ∈ 𝒦 s" "s ∈ 𝒮"
  shows "rept (reps s) μ ∈ K (reps s)"
using assms by auto

(* XXX Move this. Does this exist anywhere? More elegant pattern? *)
lemma theI':
  assumes "P a"
    and "⋀x. P x ⟹ x = a"
  shows "P (THE x. P x) ∧ (∀ y. P y ⟶ y = (THE x. P x))"
using theI assms by metis

lemma cont_cfg_defined:
  fixes cfg s
  assumes "cfg ∈ valid_cfg" "s ∈ abst (action cfg)"
  defines "x ≡ THE x. abss x = s ∧ x ∈ action cfg"
  shows "(abss x = s ∧ x ∈ action cfg) ∧ (∀ y. abss y = s ∧ y ∈ action cfg ⟶ y = x)"
proof -
  from assms(2) obtain s' where "s' ∈ action cfg" "s = abss s'" unfolding abst_def by auto
  with assms show ?thesis unfolding x_def
  by -(rule theI'[of _ s'],auto intro: K_bisim_unique MDP.valid_cfg_state_in_S dest: MDP.valid_cfgD)
qed

definition
  absc' :: "('s * ('c, t) cval) cfg ⇒ ('s * ('c, t) cval set) cfg"
where
  "absc' cfg = cfg_corec
    (abss (state cfg))
    (abst o action)
    (λ cfg s. cont cfg (THE x. abss x = s ∧ x ∈ action cfg)) cfg"

subsubsection ‹Configuration›

definition
  absc :: "('s * ('c, t) cval) cfg ⇒ ('s * ('c, t) cval set) cfg"
where
  "absc cfg = cfg_corec
    (abss (state cfg))
    (abst o action)
    (λ cfg s. cont cfg (THE x. abss x = s ∧ x ∈ action cfg)) cfg"

definition
  repcs :: "'s * ('c, t) cval ⇒ ('s * ('c, t) cval set) cfg ⇒ ('s * ('c, t) cval) cfg"
where
  "repcs s cfg = cfg_corec
    s
    (λ (s, cfg). rept s (action cfg))
    (λ (s, cfg) s'. (s', cont cfg (abss s'))) (s, cfg)"

definition
  "repc cfg = repcs (reps (state cfg)) cfg"

lemma 𝒮_state_absc_repc[simp]:
  "state cfg ∈ 𝒮 ⟹ state (absc (repc cfg)) = state cfg"
by (simp add: absc_def repc_def repcs_def)

lemma action_repc:
  "action (repc cfg) = rept (reps (state cfg)) (action cfg)"
unfolding repc_def repcs_def by simp

(* XXX Declare simp? *)
lemma action_absc:
  "action (absc cfg) = abst (action cfg)"
unfolding absc_def by simp

lemma action_absc':
  "action (absc cfg) = map_pmf abss (action cfg)"
unfolding absc_def unfolding abst_def by simp

lemma
  notes R_G.cfg_onD_state[simp del]
  assumes "state cfg ∈ 𝒮" "s' ∈ set_pmf (action (repc cfg))" "cfg ∈ R_G.cfg_on (state cfg)"
  shows "cont (repc cfg) s' = repcs s' (cont cfg (abss s'))"
using assms by (auto simp: repc_def repcs_def abss_reps_id)

lemma cont_repcs1:
  notes R_G.cfg_onD_state[simp del]
  assumes "abss s ∈ 𝒮" "s' ∈ set_pmf (action (repcs s cfg))" "cfg ∈ R_G.cfg_on (abss s)"
  shows "cont (repcs s cfg) s' = repcs s' (cont cfg (abss s'))"
using assms by (auto simp: repc_def repcs_def abss_reps_id)

lemma cont_absc_1:
  notes MDP.cfg_onD_state[simp del]
  assumes "cfg ∈ valid_cfg" "s' ∈ set_pmf (action cfg)"
  shows "cont (absc cfg) (abss s') = absc (cont cfg s')"
proof -
  define x where "x ≡ THE x. x ~ s' ∧ x ∈ set_pmf (action cfg)"
  from assms(2) have "abss s' ∈ set_pmf (abst (action cfg))" unfolding abst_def by auto
  from cont_cfg_defined[OF assms(1) this] have
    "(x ~ s' ∧ x ∈ set_pmf (action cfg)) ∧ (∀y. y ~ s' ∧ y ∈ set_pmf (action cfg) ⟶ y = x)"
  unfolding x_def .
  with assms have "s' = x" by fastforce
  then show ?thesis
  unfolding absc_def abst_def repc_def x_def using assms(2) by auto
qed

lemma state_repc:
  "state (repc cfg) = reps (state cfg)"
unfolding repc_def repcs_def by simp

lemma abss_reps_id':
  notes R_G.cfg_onD_state[simp del]
  assumes "cfg ∈ R_G.valid_cfg" "s ∈ set_pmf (action cfg)"
  shows "abss (reps s) = s"
using assms by (auto intro: abss_reps_id R_G.valid_cfg_state_in_S R_G.valid_cfgD)

(* XXX Move to different locale *)
lemma valid_cfg_coinduct[coinduct set: valid_cfg]:
  assumes "P cfg"
  assumes "⋀cfg. P cfg ⟹ state cfg ∈ S"
  assumes "⋀cfg. P cfg ⟹ action cfg ∈ K (state cfg)"
  assumes "⋀cfg t. P cfg ⟹ t ∈ action cfg ⟹ P (cont cfg t)"
  shows "cfg ∈ valid_cfg"
proof -
  from assms have "cfg ∈ MDP.cfg_on (state cfg)" by (coinduction arbitrary: cfg) auto
  moreover from assms have "state cfg ∈ S" by auto
  ultimately show ?thesis by (intro MDP.valid_cfgI)
qed

lemma state_repcD[simp]:
  assumes "cfg ∈ R_G.cfg_on s"
  shows "state (repc cfg) = reps s"
using assms unfolding repc_def repcs_def by auto

(* XXX Move *)
lemma ccompatible_subs[intro]:
  assumes "ccompatible ℛ g" "R ∈ ℛ" "u ∈ R" "u ⊢ g"
  shows "R ⊆ {u. u ⊢ g}"
using assms unfolding ccompatible_def by auto

lemma action_abscD[dest]:
  "cfg ∈ MDP.cfg_on s ⟹ action (absc cfg) ∈ 𝒦 (abss s)"
unfolding absc_def abst_def
proof simp
  assume cfg: "cfg ∈ MDP.cfg_on s"
  then have "action cfg ∈ K s" by auto
  then show "map_pmf abss (action cfg) ∈ 𝒦 (abss s)"
  proof cases
    case prems: (delay l u t)
    then have "[u ⊕ t]⇩ℛ ∈ ℛ" by auto
    moreover with prems ccompatible_inv[of l] have
      "[u ⊕ t]⇩ℛ ⊆ {v. v ⊢ PTA.inv_of A l}"
    unfolding ccompatible_def by force
    moreover from prems have "abss (l, u ⊕ t) = (l, [u ⊕ t]⇩ℛ)" by (subst abss_S) auto
    ultimately show ?thesis using prems by auto
  next
    case prems: (action l u g μ)
    then have "[u]⇩ℛ ∈ ℛ" by auto
    moreover with prems ccompatible_guard have "[u]⇩ℛ ⊆ {u. u ⊢ g}"
      by (intro ccompatible_subs) auto
    moreover have
      "map_pmf abss (action cfg)
      = map_pmf (λ(X, l). (l, region_set' ([u]⇩ℛ) (SOME r. set r = X) 0)) μ"
    proof -
      have "abss (l', [X:=0]u) = (l', region_set' ([u]⇩ℛ) (SOME r. set r = X) 0)"
        if "(X, l') ∈ μ" for X l'
      proof -
        from that prems have "A ⊢ l ⟶⇗g,μ,X⇖ l'"
          by auto
        from that prems MDP.action_closed[OF _ cfg] have "(l', [X:=0]u) ∈ S" by force
        then have "abss (l', [X:=0]u) = (l', [[X:=0]u]⇩ℛ)" by auto
        also have
          "… = (l', region_set' ([u]⇩ℛ) (SOME r. set r = X) 0)"
          using region_set'_eq(1)[OF _ _ ‹A ⊢ l ⟶⇗g,μ,X⇖ l'›] prems by auto
        finally show ?thesis .
      qed
      then show ?thesis
        unfolding prems(1)
        by (auto intro: pmf.map_cong simp: map_pmf_comp)
    qed
    ultimately show ?thesis using prems by auto
  next
    case prems: loop
    then show ?thesis by auto
  qed
qed

lemma repcs_valid[intro]:
  assumes "cfg ∈ R_G.valid_cfg" "abss s = state cfg"
  shows "repcs s cfg ∈ valid_cfg"
using assms
proof (coinduction arbitrary: cfg s)
  case 1
  then show ?case
  by (auto simp: repcs_def 𝒮_abss_S dest: R_G.valid_cfg_state_in_S)
next
  case (2 cfg' s)
  then show ?case
   by (simp add: repcs_def) (rule rept_K, auto dest: R_G.valid_cfgD)
next
  case prems: (3 s' cfg)
  let ?cfg = "cont cfg (abss s')"
  from prems have "abss s' ∈ abst (rept s (action cfg))" unfolding repcs_def abst_def by auto
  with prems have
    "abss s' ∈ action cfg"
  by (subst (asm) abst_rept_id) (auto dest: R_G.valid_cfgD)
  with prems show ?case
    by (inst_existentials ?cfg s', subst cont_repcs1)
       (auto dest: R_G.valid_cfg_state_in_S intro: R_G.valid_cfgD R_G.valid_cfg_cont)
qed

lemma repc_valid[intro]:
  assumes "cfg ∈ R_G.valid_cfg"
  shows "repc cfg ∈ valid_cfg"
using assms unfolding repc_def by (force dest: R_G.valid_cfg_state_in_S)

lemma action_abst_repcs:
  assumes "cfg ∈ R_G.valid_cfg" "abss s = state cfg"
  shows "abst (action (repcs s cfg)) = action cfg"
proof -
  from assms show ?thesis
  unfolding repc_def repcs_def
   apply simp
   apply (subst abst_rept_id)
  by (auto dest: R_G.cfg_onD_action R_G.valid_cfgD)
qed

lemma action_abst_repc:
  assumes "cfg ∈ R_G.valid_cfg"
  shows "abst (action (repc cfg)) = action cfg"
proof -
  from assms have "abss (reps (state cfg)) = state cfg" by (auto dest: R_G.valid_cfg_state_in_S)
  with action_abst_repcs[OF assms] show ?thesis unfolding repc_def by auto
qed

(* XXX Move *)
lemma state_absc:
  "state (absc cfg) = abss (state cfg)"
unfolding absc_def by auto

lemma state_repcs[simp]:
  "state (repcs s cfg) = s"
unfolding repcs_def by auto

lemma repcs_bisim:
  notes R_G.cfg_onD_state[simp del]
  assumes "cfg ∈ R_G.valid_cfg" "x ∈ S" "x ~ x'" "abss x = state cfg"
  shows "absc (repcs x cfg) = absc (repcs x' cfg)"
using assms
proof -
  from assms have "abss x' = state cfg" by auto
  from assms have "abss x' ∈ 𝒮" by auto
  then have "x' ∈ S" by (auto intro: 𝒮_abss_S)
  with assms show ?thesis  
  proof (coinduction arbitrary: cfg x x')
    case state
    then show ?case by (simp add: state_absc)
  next
    case action
    then show ?case unfolding absc_def repcs_def by (auto dest: R_G.valid_cfgD)
  next
    case prems: (cont s cfg x x')
    define cfg' where "cfg' = cont cfg s"
    define t    where "t ≡ THE y. abss y = s ∧ y ∈ action (repcs x cfg)"
    define t'   where "t' ≡THE y. abss y = s ∧ y ∈ action (repcs x' cfg)"
    from prems have valid: "repcs x cfg ∈ valid_cfg" by (intro repcs_valid)
    from prems have *: "s ∈ abst (action (repcs x cfg))"
      unfolding cfg'_def by (simp add: action_absc)
    with prems have "s ∈ action cfg" by (auto dest: R_G.valid_cfgD simp: repcs_def)
    with prems have "s ∈ 𝒮" by (auto intro: R_G.valid_cfg_action)
    from cont_cfg_defined[OF valid *] have t:
      "abss t = s" "t ∈ action (repcs x cfg)"
      unfolding t_def by auto
    have "cont (absc (repcs x cfg)) s = cont (absc (repcs x cfg)) (abss t)" using t by auto
    have "cont (absc (repcs x cfg)) s = absc (cont (repcs x cfg) t)"
      using t valid by (auto simp: cont_absc_1)
    also have "… = absc (repcs t (cont cfg s))"
      using prems t by (subst cont_repcs1) (auto dest: R_G.valid_cfgD)
    finally have cont_x: "cont (absc (repcs x cfg)) s = absc (repcs t (cont cfg s))" .
    from prems have valid: "repcs x' cfg ∈ valid_cfg" by auto
    from ‹s ∈ action cfg› prems have "s ∈ abst (action (repcs x' cfg))"
      by (auto dest: R_G.valid_cfgD simp: repcs_def)
    from cont_cfg_defined[OF valid this] have t':
      "abss t' = s" "t' ∈ action (repcs x' cfg)"
    unfolding t'_def by auto
    have "cont (absc (repcs x' cfg)) s = cont (absc (repcs x' cfg)) (abss t')" using t' by auto
    have "cont (absc (repcs x' cfg)) s = absc (cont (repcs x' cfg) t')"
      using t' valid by (auto simp: cont_absc_1)
    also have "… = absc (repcs t' (cont cfg s))"
      using prems t' by (subst cont_repcs1) (auto dest: R_G.valid_cfgD)
    finally have "cont (absc (repcs x' cfg)) s = absc (repcs t' (cont cfg s))" .
    with cont_x ‹s ∈ action cfg› prems(1) t t' ‹s ∈ 𝒮›
    show ?case
      by (inst_existentials "cont cfg s" t t')
         (auto intro: 𝒮_abss_S R_G.valid_cfg_action R_G.valid_cfg_cont)
  qed
qed

named_theorems R_G_I

lemmas R_G.valid_cfg_state_in_S[R_G_I] R_G.valid_cfgD[R_G_I] R_G.valid_cfg_action

(* XXX Simplifier looping problems on cfg_on
   If R_G.cfg_onD_state is not removed from simpset, the simplifier rewrites state cfg = state cfg.
*)
lemma absc_repcs_id:
  notes R_G.cfg_onD_state[simp del]
  assumes "cfg ∈ R_G.valid_cfg" "abss s = state cfg"
  shows "absc (repcs s cfg) = cfg" using assms
proof (subst eq_commute, coinduction arbitrary: cfg s)
  case state
  then show ?case by (simp add: absc_def repc_def repcs_def)
next
  case prems: (action cfg)
  then show ?case by (auto simp: action_abst_repcs action_absc)
next
  case prems: (cont s')
  define cfg' where "cfg' ≡ repcs s cfg"
  define t    where "t    ≡ THE x. abss x = s' ∧ x ∈ set_pmf (action cfg')"
  from prems have "cfg ∈ R_G.cfg_on (state cfg)" "state cfg ∈ 𝒮" by (auto dest: R_G_I)
  then have *: "cfg ∈ R_G.cfg_on (abss (reps (state cfg)))" "abss (reps (state cfg)) ∈ 𝒮" by auto
  from prems have "s' ∈ 𝒮" by (auto intro: R_G.valid_cfg_action)
  from prems have valid: "cfg' ∈ valid_cfg" unfolding cfg'_def by (intro repcs_valid)
  from prems have "s' ∈ abst (action cfg')" unfolding cfg'_def by (subst action_abst_repcs)
  from cont_cfg_defined[OF valid this] have t:
    "abss t = s'" "t ∈ action cfg'"
  unfolding t_def cfg'_def by auto
  with prems have "t ~ reps (abss t)"
   apply -
   apply (subst 𝒮_abss_reps)
  by (auto intro: R_G.valid_cfg_action)
  have "cont (absc cfg') s' = cont (absc cfg') (abss t)" using t by auto
  have "cont (absc cfg') s' = absc (cont cfg' t)" using t valid by (auto simp: cont_absc_1)
  also have "… = absc (repcs t (cont cfg s'))" using prems t * ‹t ~ _› valid
  by (fastforce dest: R_G_I intro: repcs_bisim simp: cont_repcs1 cfg'_def)
  finally show ?case
   apply -
   apply (rule exI[where x = "cont cfg s'"], rule exI[where x = t])
  unfolding cfg'_def using prems t by (auto intro: R_G.valid_cfg_cont)
qed

(* XXX Simplifier looping problems on cfg_on
   If R_G.cfg_onD_state is not removed from simpset, the simplifier rewrites state cfg = state cfg.
*)
lemma absc_repc_id:
  notes R_G.cfg_onD_state[simp del]
  assumes "cfg ∈ R_G.valid_cfg"
  shows "absc (repc cfg) = cfg" using assms
unfolding repc_def using assms by (subst absc_repcs_id) (auto dest: R_G_I)

lemma K_cfg_map_absc:
  "cfg ∈ valid_cfg ⟹ K_cfg (absc cfg) = map_pmf absc (K_cfg cfg)"
by (auto simp: K_cfg_def map_pmf_comp action_absc abst_def cont_absc_1 intro: map_pmf_cong)

(* XXX Move *)
lemma smap_comp:
  "(smap f o smap g) = smap (f o g)"
by (auto simp: stream.map_comp)

lemma state_abscD[simp]:
  assumes "cfg ∈ MDP.cfg_on s"
  shows "state (absc cfg) = abss s"
using assms unfolding absc_def by auto

(* XXX Move to different locale *)
lemma R_G_valid_cfg_coinduct[coinduct set: valid_cfg]:
  assumes "P cfg"
  assumes "⋀cfg. P cfg ⟹ state cfg ∈ 𝒮"
  assumes "⋀cfg. P cfg ⟹ action cfg ∈ 𝒦 (state cfg)"
  assumes "⋀cfg t. P cfg ⟹ t ∈ action cfg ⟹ P (cont cfg t)"
  shows "cfg ∈ R_G.valid_cfg"
proof -
  from assms have "cfg ∈ R_G.cfg_on (state cfg)" by (coinduction arbitrary: cfg) auto
  moreover from assms have "state cfg ∈ 𝒮" by auto
  ultimately show ?thesis by (intro R_G.valid_cfgI)
qed

lemma absc_valid[intro]:
  assumes "cfg ∈ valid_cfg"
  shows "absc cfg ∈ R_G.valid_cfg"
using assms
proof (coinduction arbitrary: cfg)
  case 1
  then show ?case by (auto simp: absc_def dest: MDP.valid_cfg_state_in_S)
next
  case (2 cfg')
  then show ?case by (subst state_abscD) (auto intro: MDP.valid_cfgD action_abscD)
next
  case prems: (3 s' cfg)
  define t where "t ≡ THE x. abss x = s' ∧ x ∈ set_pmf (action cfg)"
  let ?cfg = "cont cfg t"
  from prems obtain s where "s' = abss s" "s ∈ action cfg" by (auto simp: action_absc')
  with cont_cfg_defined[OF prems(1), of s'] have
    "abss t = s'" "t ∈ set_pmf (action cfg)"
    "∀y. abss y = s' ∧ y ∈ set_pmf (action cfg) ⟶ y = t"
  unfolding t_def abst_def by auto
  with prems show ?case
    by (inst_existentials ?cfg)
       (auto intro: MDP.valid_cfg_cont simp: abst_def action_absc absc_def t_def)
qed

lemma K_cfg_set_absc:
  assumes "cfg ∈ valid_cfg" "cfg' ∈ K_cfg cfg"
  shows "absc cfg' ∈ K_cfg (absc cfg)"
using assms by (auto simp: K_cfg_map_absc)

lemma abst_action_repcs:
  assumes "cfg ∈ R_G.valid_cfg" "abss s = state cfg"
  shows "abst (action (repcs s cfg)) = action cfg"
unfolding repc_def repcs_def using assms by (simp, subst abst_rept_id) (auto intro: R_G_I)

lemma abst_action_repc:
  assumes "cfg ∈ R_G.valid_cfg"
  shows "abst (action (repc cfg)) = action cfg"
using assms unfolding repc_def by (auto intro: abst_action_repcs simp: R_G_I)

lemma K_elem_abss_inj':
  assumes "μ ∈ K s"
    and "s ∈ S"
  shows "inj_on abss (set_pmf μ)"
using assms K_elem_abss_inj by (simp add: K_bisim_unique inj_onI)

lemma K_cfg_rept_aux:
  assumes "cfg ∈ R_G.valid_cfg" "abss s = state cfg" "x ∈ rept s (action cfg)"
  defines "t ≡ λ cfg'. THE s'. s' ∈ rept s (action cfg) ∧ s' ~ x"
  shows "t cfg' = x"
proof -
  from assms have "rept s (action cfg) ∈ K s" "s ∈ S" by (auto simp: R_G_I 𝒮_abss_S)
  from K_bisim_unique[OF this(2,1) _ assms(3)] assms(3) show ?thesis unfolding t_def by blast
qed

lemma K_cfg_rept_action:
  assumes "cfg ∈ R_G.valid_cfg" "abss s = state cfg" "cfg' ∈ set_pmf (K_cfg cfg)"
  shows "abss (THE s'. s' ∈ rept s (action cfg) ∧ abss s' = state cfg') = state cfg'"
proof -
  let ?μ = "rept s (action cfg)"
  from abst_rept_id assms have "action cfg = abst ?μ" by (auto simp: R_G_I)
  moreover from assms have "state cfg' ∈ action cfg" by (auto simp: set_K_cfg)
  ultimately have "state cfg' ∈ abst ?μ" by simp
  then obtain s' where "s' ∈ ?μ" "abss s' = state cfg'" by (auto simp: abst_def pmf.set_map)
  with K_cfg_rept_aux[OF assms(1,2) this(1)] show ?thesis by auto
qed

lemma K_cfg_map_repcs:
  assumes "cfg ∈ R_G.valid_cfg" "abss s = state cfg"
  defines "repc' ≡ (λ cfg'. repcs (THE s'. s' ∈ rept s (action cfg) ∧ abss s' = state cfg') cfg')"
  shows "K_cfg (repcs s cfg) = map_pmf repc' (K_cfg cfg)"
proof -
  let ?μ = "rept s (action cfg)"
  define t where "t ≡ λ cfg'. THE s. s ∈ ?μ ∧ abss s = state cfg'"
  have t: "t (cont cfg (abss s')) = s'" if "s' ∈ ?μ" for s'
    using K_cfg_rept_aux[OF assms(1,2) that] unfolding t_def by auto
  show ?thesis
    unfolding K_cfg_def using t
    by (subst abst_action_repcs[symmetric])
       (auto simp: repc_def repcs_def t_def map_pmf_comp abst_def assms intro: map_pmf_cong)
qed

lemma K_cfg_map_repc:
  assumes "cfg ∈ R_G.valid_cfg"
  defines
    "repc' cfg' ≡ repcs (THE s. s ∈ rept (reps (state cfg)) (action cfg) ∧ abss s = state cfg') cfg'"
  shows 
    "K_cfg (repc cfg) = map_pmf repc' (K_cfg cfg)"
using assms unfolding repc'_def repc_def by (auto simp: R_G_I K_cfg_map_repcs)

lemma R_G_K_cfg_valid_cfgD:
  assumes "cfg ∈ R_G.valid_cfg" "cfg' ∈ K_cfg cfg"
  shows "cfg' = cont cfg (state cfg')" "state cfg' ∈ action cfg"
proof -
  from assms(2) obtain s where "s ∈ action cfg" "cfg' = cont cfg s" by (auto simp: set_K_cfg)
  with assms show
    "cfg' = cont cfg (state cfg')" "state cfg' ∈ action cfg"
  by (auto intro: R_G.valid_cfg_state_in_S R_G.valid_cfgD)
qed

lemma K_cfg_valid_cfgD:
  assumes "cfg ∈ valid_cfg" "cfg' ∈ K_cfg cfg"
  shows "cfg' = cont cfg (state cfg')" "state cfg' ∈ action cfg"
proof -
  from assms(2) obtain s where "s ∈ action cfg" "cfg' = cont cfg s" by (auto simp: set_K_cfg)
  with assms show
    "cfg' = cont cfg (state cfg')" "state cfg' ∈ action cfg"
  by auto
qed

(* XXX Move *)
lemma absc_bisim_abss:
  assumes "absc x = absc x'"
  shows "state x ~ state x'"
proof -
  from assms have "state (absc x) = state (absc x')" by simp
  then show ?thesis by (simp add: state_absc)
qed

(* XXX Move *)
lemma K_cfg_bisim_unique:
  assumes "cfg ∈ valid_cfg" and "x ∈ K_cfg cfg" "x' ∈ K_cfg cfg" and "state x ~ state x'"
  shows "x = x'"
proof -
  define t where "t ≡ THE x'. x' ~ state x ∧ x' ∈ set_pmf (action cfg)"
  from K_cfg_valid_cfgD assms have *:
    "x  = cont cfg (state x)"  "state x ∈ action cfg"
    "x' = cont cfg (state x')" "state x' ∈ action cfg"
    by auto
  with assms have
    "cfg ∈ valid_cfg" "abss (state x) ∈ set_pmf (abst (action cfg))"
    unfolding abst_def by auto
  with cont_cfg_defined[of cfg "abss (state x)"] have
    "∀y. y ~ state x ∧ y ∈ set_pmf (action cfg) ⟶ y = t"
    unfolding t_def by auto
  with * assms(4) have "state x' = t" "state x = t" by fastforce+
  with * show ?thesis by simp
qed

lemma absc_distr_self:
  "MDP.MC.T (absc cfg) = distr (MDP.MC.T cfg) MDP.MC.S (smap absc)" if "cfg ∈ valid_cfg"
  using ‹cfg ∈ _›
proof (coinduction arbitrary: cfg rule: MDP.MC.T_coinduct)
  case prob
  show ?case by (rule MDP.MC.T.prob_space_distr, simp)
next
  case sets
  show ?case by auto
next
  case prems: (cont cfg)
  define t  where "t  ≡ λ y. THE x. y = absc x ∧ x ∈ K_cfg cfg"
  define M' where "M' ≡ λ cfg. distr (MDP.MC.T (t cfg)) MDP.MC.S (smap absc)"
  show ?case
  proof (rule exI[where x = M'], safe, goal_cases)
    case A: (1 y)
    from A prems obtain x' where "y = absc x'" "x' ∈ K_cfg cfg" by (auto simp: K_cfg_map_absc)
    with K_cfg_bisim_unique[OF prems _ _ absc_bisim_abss] have
      "y = absc (t y)" "x' = t y"
      unfolding t_def by (auto intro: theI2)
    moreover have "x' ∈ valid_cfg" using ‹x' ∈ _› prems by auto
    ultimately show ?case unfolding M'_def by auto
  next
    case 5
    show ?case unfolding M'_def
      apply (subst distr_distr)
        prefer 3
        apply (subst MDP.MC.T_eq_bind)
        apply (subst distr_bind)
           prefer 4
           apply (subst distr_distr)
             prefer 3
             apply (subst K_cfg_map_absc)
              apply (rule prems)
             apply (subst map_pmf_rep_eq)
             apply (subst bind_distr)
               prefer 4
               apply (rule bind_measure_pmf_cong)
                 prefer 3
      subgoal premises A for x
      proof -
        have "t (absc x) = x" unfolding t_def
        proof (rule the_equality, goal_cases)
          case 1 with A show ?case by simp
        next
          case (2 x')
          with K_cfg_bisim_unique[OF prems _ A absc_bisim_abss] show ?case by simp
        qed
        then show ?thesis by (auto simp: comp_def)
      qed
      by (fastforce
          simp:  space_subprob_algebra MC_syntax.in_S
          intro: bind_measure_pmf_cong MDP.MC.T.subprob_space_distr MDP.MC.T.prob_space_distr
          )+
  qed (auto simp: M'_def intro: MDP.MC.T.prob_space_distr)
qed

lemma R_G_trace_space_distr_eq:
  assumes "cfg ∈ R_G.valid_cfg" "abss s = state cfg"
  shows "MDP.MC.T cfg = distr (MDP.MC.T (repcs s cfg)) MDP.MC.S (smap absc)"
using assms
proof (coinduction arbitrary: cfg s rule: MDP.MC.T_coinduct)
  case prob
  show ?case by (rule MDP.MC.T.prob_space_distr, simp) 
next
  case sets
  show ?case by auto
next
  case prems: (cont cfg s)
  let ?μ = "rept s (action cfg)"
  define repc' where "repc' ≡ λ cfg'. repcs (THE s. s ∈ ?μ ∧ abss s = state cfg') cfg'"
  define M' where "M' ≡ λ cfg. distr (MDP.MC.T (repc' cfg)) MDP.MC.S (smap absc)"
  show ?case
  proof (intro exI[where x = M'], safe, goal_cases)
    case A: (1 cfg')
    with K_cfg_rept_action[OF prems] have
      "abss (THE s. s ∈ ?μ ∧ abss s = state cfg') = state cfg'"
    by auto
    moreover from A prems have "cfg' ∈ R_G.valid_cfg" by auto
    ultimately show ?case unfolding M'_def repc'_def by best
  next
    case 4
    show ?case unfolding M'_def by (rule MDP.MC.T.prob_space_distr, simp)
  next
    case 5
    have *: "smap absc ∘ (##) (repc' cfg') = (##) cfg' ∘ smap absc"
    if "cfg' ∈ set_pmf (K_cfg cfg)" for cfg'
    proof -
      from K_cfg_rept_action[OF prems that] have
        "abss (THE s. s ∈ ?μ ∧ abss s = state cfg') = state cfg'"
      .
      with prems that have *:
        "absc (repc' cfg') = cfg'"
      unfolding repc'_def by (subst absc_repcs_id, auto)
      then show "(smap absc ∘ (##) (repc' cfg')) = ((##) cfg' ∘ smap absc)" by auto
    qed
    from prems show ?case unfolding M'_def
      apply (subst distr_distr)
        apply simp+
      apply (subst MDP.MC.T_eq_bind)
      apply (subst distr_bind)
         prefer 2
         apply simp
        apply (rule MDP.MC.distr_Stream_subprob)
       apply simp
      apply (subst distr_distr)
        apply simp+
      apply (subst K_cfg_map_repcs[OF prems])
      apply (subst map_pmf_rep_eq)
      apply (subst bind_distr)
    by (fastforce simp: *[unfolded repc'_def] repc'_def space_subprob_algebra MC_syntax.in_S
                  intro: bind_measure_pmf_cong MDP.MC.T.subprob_space_distr)+
  qed (simp add: M'_def)+
qed

lemma repc_inj_on_K_cfg:
  assumes "cfg ∈ R_G.cfg_on s" "s ∈ 𝒮"
  shows "inj_on repc (set_pmf (K_cfg cfg))"
  using assms
  by (intro inj_on_inverseI[where g = absc], subst absc_repc_id)
     (auto intro: R_G.valid_cfgD R_G.valid_cfgI R_G.valid_cfg_state_in_S)

lemma smap_absc_iff:
  assumes "⋀ x y. x ∈ X ⟹ smap abss x = smap abss y ⟹ y ∈ X"
  shows "(smap state xs ∈ X) = (smap (λz. abss (state z)) xs ∈ smap abss ` X)"
proof (safe, goal_cases)
  case 1
  then show ?case unfolding image_def
    by clarify (inst_existentials "smap state xs", auto simp: stream.map_comp)
next
  case prems: (2 xs')
  have
    "smap (λz. abss (state z)) xs = smap abss (smap state xs)"
  by (auto simp: comp_def stream.map_comp)
  with prems have "smap abss (smap state xs) = smap abss xs'" by simp
  with prems(2) assms show ?case by auto
qed

lemma valid_abss_reps[simp]:
  assumes "cfg ∈ R_G.valid_cfg"
  shows "abss (reps (state cfg)) = state cfg"
using assms by (subst 𝒮_abss_reps) (auto intro: R_G.valid_cfg_state_in_S)

lemma in_space_UNIV: "x ∈ space (count_space UNIV)"
  by simp

lemma S_reps_𝒮_aux:
  "reps (l, R) ∈ S ⟹ (l, R) ∈ 𝒮"
  using ccompatible_inv unfolding reps_def ccompatible_def 𝒮_def S_def
  by (cases "R ∈ ℛ"; auto simp: non_empty)

(* XXX Move *)
lemma S_reps_𝒮[intro]:
  "reps s ∈ S ⟹ s ∈ 𝒮"
  using S_reps_𝒮_aux by (metis surj_pair)

lemma absc_valid_cfg_eq:
  "absc ` valid_cfg = R_G.valid_cfg"
  apply safe
  subgoal
    by auto
  subgoal for cfg
    using absc_repcs_id[where s = "reps (state cfg)"]
    by - (frule repcs_valid[where s = "reps (state cfg)"]; force intro: imageI)
  done

lemma action_repcs:
  "action (repcs (l, u) cfg) = rept (l, u) (action cfg)"
  by (simp add: repcs_def)

subsection ‹Equalities Between Measures of Trace Spaces›

(* TODO: Clean *)
lemma path_measure_eq_absc1_new:
  fixes cfg s
  defines "cfg' ≡ absc cfg"
  assumes valid: "cfg ∈ valid_cfg"
  assumes X[measurable]: "X ∈ R_G.St" and Y[measurable]: "Y ∈ MDP.St"
  assumes P: "AE x in (R_G.T cfg'). P x" and Q: "AE x in (MDP.T cfg). Q x"
  assumes P'[measurable]: "Measurable.pred R_G.St P"
      and Q'[measurable]: "Measurable.pred MDP.St Q"
  assumes X_Y_closed: "⋀ x y. P x ⟹ smap abss y = x ⟹ x ∈ X ⟹ y ∈ Y ∧ Q y"
  assumes Y_X_closed: "⋀ x y. Q y ⟹ smap abss y = x ⟹ y ∈ Y ⟹ x ∈ X ∧ P x"
  shows
    "emeasure (R_G.T cfg') X = emeasure (MDP.T cfg) Y"
proof -
  have *: "stream_all2 (λs. (=) (absc s)) x y = stream_all2 (=) (smap absc x) y" for x y
    by simp
  have *: "stream_all2 (λs t. t = absc s) x y = stream_all2 (=) y (smap absc x)" for x y
    using stream.rel_conversep[of "λs t. t = absc s"]
    by (simp add: conversep_iff[abs_def])

  from P have "emeasure (R_G.T cfg') X = emeasure (R_G.T cfg') {x ∈ X. P x}"
    by (auto intro: emeasure_eq_AE)
  moreover from Q have "emeasure (MDP.T cfg) Y = emeasure (MDP.T cfg) {y ∈ Y. Q y}"
    by (auto intro: emeasure_eq_AE)
  moreover show ?thesis
   apply (simp only: calculation)
    unfolding R_G.T_def MDP.T_def
    apply (simp add: emeasure_distr)
    apply (rule sym)
    apply (rule T_eq_rel_half[where f = absc and S = valid_cfg])
         apply (rule HOL.refl)
    apply measurable
      apply (simp add: space_stream_space)
    subgoal
      unfolding rel_set_strong_def stream.rel_eq
      apply (intro allI impI)
      apply (drule stream.rel_mono_strong[where Ra = "λs t. t = absc s"])
       apply (simp; fail)
      subgoal for x y
      using Y_X_closed[of "smap state x" "smap state (smap absc x)" for x y]
      using X_Y_closed[of "smap state (smap absc x)" "smap state x" for x y]
      by (auto simp: * stream.rel_eq stream.map_comp state_absc)+
    done
    subgoal
      apply (auto intro!: rel_funI)
      apply (subst K_cfg_map_absc)
       defer
       apply (subst pmf.rel_map(2))
       apply (rule rel_pmf_reflI)
      by auto
    subgoal
      using valid unfolding cfg'_def by simp
    done
qed

(* TODO: Clean duplication *)
lemma path_measure_eq_repcs1_new:
  fixes cfg s
  defines "cfg' ≡ repcs s cfg"
  assumes s: "abss s = state cfg"
  assumes valid: "cfg ∈ R_G.valid_cfg"
  assumes X[measurable]: "X ∈ R_G.St" and Y[measurable]: "Y ∈ MDP.St"
  assumes P: "AE x in (R_G.T cfg). P x" and Q: "AE x in (MDP.T cfg'). Q x"
  assumes P'[measurable]: "Measurable.pred R_G.St P"
      and Q'[measurable]: "Measurable.pred MDP.St Q"
  assumes X_Y_closed: "⋀ x y. P x ⟹ smap abss y = x ⟹ x ∈ X ⟹ y ∈ Y ∧ Q y"
  assumes Y_X_closed: "⋀ x y. Q y ⟹ smap abss y = x ⟹ y ∈ Y ⟹ x ∈ X ∧ P x"
  shows
    "emeasure (R_G.T cfg) X = emeasure (MDP.T cfg') Y"
proof -
  have *: "stream_all2 (λs t. t = absc s) x y = stream_all2 (=) y (smap absc x)" for x y
    using stream.rel_conversep[of "λs t. t = absc s"]
    by (simp add: conversep_iff[abs_def])
  from P X have
    "emeasure (R_G.T cfg) X = emeasure (R_G.T cfg) {x ∈ X. P x}"
    by (auto intro: emeasure_eq_AE)
  moreover from Q Y have
    "emeasure (MDP.T cfg') Y = emeasure (MDP.T cfg') {y ∈ Y. Q y}"
    by (auto intro: emeasure_eq_AE)
  moreover show ?thesis
    apply (simp only: calculation)
    unfolding R_G.T_def MDP.T_def
    apply (simp add: emeasure_distr)
    apply (rule sym)
    apply (rule T_eq_rel_half[where f = absc and S = valid_cfg])
         apply (rule HOL.refl)
        apply measurable
      apply (simp add: space_stream_space)
    subgoal
      unfolding rel_set_strong_def stream.rel_eq
      apply (intro allI impI)
      apply (drule stream.rel_mono_strong[where Ra = "λs t. t = absc s"])
       apply (simp; fail)
      subgoal for x y
        using Y_X_closed[of "smap state x" "smap state (smap absc x)" for x y]
        using X_Y_closed[of "smap state (smap absc x)" "smap state x" for x y]
        by (auto simp: * stream.rel_eq stream.map_comp state_absc)+
      done
    subgoal
      apply (auto intro!: rel_funI)
      apply (subst K_cfg_map_absc)
       defer
       apply (subst pmf.rel_map(2))
       apply (rule rel_pmf_reflI)
      by auto
    subgoal
      using valid unfolding cfg'_def by (auto simp: s absc_repcs_id)
    done
qed

lemma region_compatible_suntil1:
  assumes "(holds (λx. φ (reps x)) suntil holds (λx. ψ (reps x))) (smap abss x)"
      and "pred_stream (λ s. φ (reps (abss s)) ⟶ φ s) x"
      and "pred_stream (λ s. ψ (reps (abss s)) ⟶ ψ s) x"
  shows "(holds φ suntil holds ψ) x" using assms
proof (induction "smap abss x" arbitrary: x rule: suntil.induct)
  case base
  then show ?case by (auto intro: suntil.base simp: stream.pred_set)
next
  case step
  have
    "pred_stream (λs. φ (reps (abss s)) ⟶ φ s) (stl x)"
    "pred_stream (λs. ψ (reps (abss s)) ⟶ ψ s) (stl x)"
    using step.prems apply (cases x; auto)
    using step.prems apply (cases x; auto)
    done
  with step.hyps(3)[of "stl x"] have "(holds φ suntil holds ψ) (stl x)" by auto
  with step.prems step.hyps(1-2) show ?case by (auto intro: suntil.step simp: stream.pred_set)
qed

lemma region_compatible_suntil2:
  assumes "(holds φ suntil holds ψ) x"
      and "pred_stream (λ s. φ s ⟶ φ (reps (abss s))) x"
      and "pred_stream (λ s. ψ s ⟶ ψ (reps (abss s))) x"
  shows "(holds (λx. φ (reps x)) suntil holds (λx. ψ (reps x))) (smap abss x)" using assms
proof (induction x rule: suntil.induct)
  case (base x)
  then show ?case by (auto intro: suntil.base simp: stream.pred_set)
next
  case (step x)
  have
    "pred_stream (λs. φ s ⟶ φ (reps (abss s))) (stl x)"
    "pred_stream (λs. ψ s ⟶ ψ (reps (abss s))) (stl x)"
    using step.prems apply (cases x; auto)
    using step.prems apply (cases x; auto)
    done
  with step show ?case by (auto intro: suntil.step simp: stream.pred_set)
qed

lemma region_compatible_suntil:
  assumes "pred_stream (λ s. φ (reps (abss s)) ⟷ φ s) x"
      and "pred_stream (λ s. ψ (reps (abss s)) ⟷ ψ s) x"
  shows "(holds (λx. φ (reps x)) suntil holds (λx. ψ (reps x))) (smap abss x)
     ⟷ (holds φ suntil holds ψ) x" using assms
using assms region_compatible_suntil1 region_compatible_suntil2 unfolding stream.pred_set by blast

lemma reps_abss_S:
  assumes "reps (abss s) ∈ S"
  shows "s ∈ S"
by (simp add: S_reps_𝒮 𝒮_abss_S assms)

lemma measurable_sset[measurable (raw)]:
  assumes f[measurable]: "f ∈ N →⇩M stream_space M" and P[measurable]: "Measurable.pred M P"
  shows "Measurable.pred N (λx. ∀s∈sset (f x). P s)"
proof -
  have *: "(λx. ∀s∈sset (f x). P s) = (λx. ∀i. P (f x !! i))"
    by (simp add: sset_range)
  show ?thesis
    unfolding * by measurable
qed

lemma path_measure_eq_repcs''_new:
  notes in_space_UNIV[measurable]
  fixes cfg φ ψ s
  defines "cfg' ≡ repcs s cfg"
  defines "φ' ≡ absp φ" and "ψ' ≡ absp ψ"
  assumes s: "abss s = state cfg"
  assumes valid: "cfg ∈ R_G.valid_cfg"
  assumes valid': "cfg' ∈ valid_cfg"
  assumes equiv_φ: "⋀ x. pred_stream (λ s. s ∈ S) x
                    ⟹ pred_stream (λ s. φ (reps (abss s)) ⟷ φ s) (state cfg' ## x)"
    and equiv_ψ: "⋀ x. pred_stream (λ s. s ∈ S) x
                    ⟹ pred_stream (λ s. ψ (reps (abss s)) ⟷ ψ s) (state cfg' ## x)"
  shows
    "emeasure (R_G.T cfg)  {x∈space R_G.St. (holds φ' suntil holds ψ') (state cfg  ## x)} =
     emeasure (MDP.T cfg') {x∈space MDP.St. (holds φ  suntil holds ψ)  (state cfg' ## x)}"
  unfolding cfg'_def
  apply (rule path_measure_eq_repcs1_new[where P = "pred_stream (λ s. s ∈ 𝒮)" and Q = "pred_stream (λ s. s ∈ S)"])
           apply fact
          apply fact
         apply measurable
  subgoal
    unfolding R_G.T_def
    apply (subst AE_distr_iff)
      apply (auto; fail)
     apply (auto simp: stream.pred_set; fail)
    apply (rule AE_mp[OF MDP.MC.AE_T_enabled AE_I2])
    using R_G.pred_stream_cfg_on[OF valid] by (auto simp: stream.pred_set)
  subgoal
    unfolding MDP.T_def
    apply (subst AE_distr_iff)
      apply (auto; fail)
     apply (auto simp: stream.pred_set; fail)
    apply (rule AE_mp[OF MDP.MC.AE_T_enabled AE_I2])
    using MDP.pred_stream_cfg_on[OF valid', unfolded cfg'_def] by (auto simp: stream.pred_set)
     apply measurable
  subgoal premises prems for ys xs
    apply safe
      apply measurable
    unfolding φ'_def ψ'_def absp_def
     apply (subst region_compatible_suntil[symmetric])
    subgoal
    proof -
      from prems have "pred_stream (λs. s ∈ S) xs" using 𝒮_abss_S by (auto simp: stream.pred_set)
      with equiv_φ show ?thesis by (simp add: cfg'_def)
    qed
    subgoal
    proof -
      from prems have "pred_stream (λs. s ∈ S) xs" using 𝒮_abss_S by (auto simp: stream.pred_set)
      with equiv_ψ show ?thesis by (simp add: cfg'_def)
    qed
    using valid prems
     apply (auto simp: s comp_def φ'_def ψ'_def absp_def dest: R_G.valid_cfg_state_in_S)
    apply (auto simp: stream.pred_set intro: 𝒮_abss_S dest: R_G.valid_cfg_state_in_S)
    done
  subgoal premises prems for ys xs
    apply safe
      using prems apply (auto simp: stream.pred_set 𝒮_abss_S; measurable; fail)
    using prems unfolding φ'_def ψ'_def absp_def comp_def apply (simp add: stream.map_comp)
     apply (subst (asm) region_compatible_suntil[symmetric])
    subgoal
    proof -
      from prems have "pred_stream (λs. s ∈ S) xs" using 𝒮_abss_S by auto
      with equiv_φ show ?thesis using valid by (simp add: cfg'_def repc_def)
    qed
    subgoal
    proof -
      from prems have "pred_stream (λs. s ∈ S) xs" using 𝒮_abss_S by auto
      with equiv_ψ show ?thesis using valid  by (simp add: cfg'_def)
    qed
    using valid prems by (auto simp: s S_abss_𝒮 stream.pred_set dest: R_G.valid_cfg_state_in_S)
  done

end (* Probabilistic Timed Automaton Regions *)

end (* Theory *)