Deciding game invariance

In a previous paper, Duchêne and Rigo introduced the notion of invariance for take-away games on heaps. Roughly speaking, these are games whose rulesets do not depend on the position. Given a sequence S of positive tuples of integers, the question of whether there exists an invariant game having S as set of P -positions is relevant. In particular, it was recently proved by Larsson et al. that if S is a pair of complementary Beatty sequences, then the answer to this question is always positive. In this paper, we show that for a fairly large set of sequences (expressed by infinite words), the answer to this question is decidable.

Authors

• Eric Duchêne
• Aline Parreau
• Michel Rigo

Keywords

• Combinatorial game
• Impartial game
• Decision problem
• First-order logic
• Recognizable sets of integers