Research projects

Project CEMAPRE internal

TitleMixture of winning conditions in combinatorial games
ParticipantsTomoaki Abuku, Alda Carvalho (Principal Investigator), Richard J Nowakowski, Carlos P Santos, Koki Suetsugu
SummaryIn combinatorial game theory, the two most commonly studied winning conventions are the normal play
convention and the misère play convention. Under the former, the player who has no available moves
on their turn loses; under the latter, the opposite holds — the player with no available moves
wins. Numerous take-away games (pile games) have been analyzed in the specialized literature, with
NIM and WYTHOFF NIM being the most paradigmatic examples.

It is entirely natural to consider a mixture of these conventions. For instance, there may be piles
of blue stones and piles of red stones. If the final move is made on one of the former, the player
who makes that last move wins; if the final move is made on one of the latter, the player who makes
that last move loses. The mathematics of such mixtures is surprisingly rich and sophisticated to
analyze, both in terms of outcomes, periodicity, and algebraic structure in general. There are also
connections with ancient games, notably the Japanese game GOISHI HIROI.