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arXiv · 1701.02819

Tetris Hypergraphs and Combinations of Impartial Games

Endre Boros·Vladimir Gurvich·Nhan Bao Ho·Kazuhisa Makino·Peter Mursic
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Abstract

The Sprague-Grundy (SG) theory reduces the sum of impartial games to the classical game of $NIM$. We generalize the concept of sum and introduce $\cH$-combinations of impartial games for any hypergraph $\cH$. In particular, we introduce the game $NIM_\cH$ which is the $\cH$-combination of single pile $NIM$ games. An impartial game is called SG decreasing if its SG value is decreased by every move. Extending the SG theory, we reduce the $\cH$-combination of SG decreasing games to $NIM_\cH$. We call $\cH$ a Tetris hypergraph if $NIM_\cH$ is SG decreasing. We provide some necessary and some sufficient conditions for a hypergraph to be Tetris.

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Endre Boros, Vladimir Gurvich, Nhan Bao Ho, Kazuhisa Makino, Peter Mursic. 2017-01-11. Tetris Hypergraphs and Combinations of Impartial Games. https://arxiv.org/abs/1701.02819

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