A game-theoretic approach to constraint satisfaction

www.cse.ucsc.edu / ¡ kolaitis We shed light on the connections between different approaches to constraint satisfaction by showing that the main consistency concepts used to derive tractability results for constraint satisfaction are intimately related to certain combinatorial pebble games, called the existential £-pebble games, that were originally introduced in the context of Datalog. The crucial insight relating pebble games to constraint satisfaction is that the key concept of strong £-consistency is equivalent to a condition on winning strategies for the Duplicator player in the existential £-pebble game. We use this insight to show that strong £-consistency can be established if and only if the Duplicator wins the existential £-pebbl