A joint paper with Davide Leonessi, in which we prove that every countable ordinal arises as the game value of a position in infinite draughts, and this result is optimal for games having countably many options at each move. In short, the omega one of infinite draughts is true omega one.

- J. D. Hamkins and D. Leonessi, “Transfinite game values in infinite draughts,” Mathematics arXiv, 2021.

[Bibtex]`@ARTICLE{HamkinsLeonessi:Transfinite-game-values-in-infinite-draughts, author = {Joel David Hamkins and Davide Leonessi}, title = {Transfinite game values in infinite draughts}, journal = {Mathematics arXiv}, year = {2021}, volume = {}, number = {}, pages = {}, month = {}, note = {Under review}, abstract = {}, keywords = {under-review}, source = {}, doi = {}, eprint = {2111.02053}, archivePrefix = {arXiv}, primaryClass = {math.LO}, url = {http://jdh.hamkins.org/transfinite-game-values-in-infinite-draughts}, }`

Download the paper at arXiv:2111.02053

**Abstract.** Infinite draughts, or checkers, is played just like the finite game, but on an infinite checkerboard extending without bound in all four directions. We prove that every countable ordinal arises as the game value of a position in infinite draughts. Thus, there are positions from which Red has a winning strategy enabling her to win always in finitely many moves, but the length of play can be completely controlled by Black in a manner as though counting down from a given countable ordinal.

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