Abstract
This is a formalization of the article Knight's Tour Revisited by
Cull and De Curtins where they prove the existence of a Knight's
path for arbitrary n × m-boards with min(n,m) ≥
5. If n · m is even, then there exists a Knight's
circuit. A Knight's Path is a sequence of moves of a Knight on a
chessboard s.t. the Knight visits every square of a chessboard
exactly once. Finding a Knight's path is a an instance of the
Hamiltonian path problem. A Knight's circuit is a Knight's path,
where additionally the Knight can move from the last square to the
first square of the path, forming a loop. During the formalization
two mistakes in the original proof were discovered. These mistakes
are corrected in this formalization.