Lower Bounds for Existential Pebble Games and k-Consistency Tests

The existential k-pebble game characterizes the expressive power of the existential-positive k-variable fragment of first-order logic on finite structures. The winner of the existential k-pebble game on two given finite structures can be determined in time O(n2k) by dynamic programming on the graph...

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Vydáno v:Logical methods in computer science Ročník 9, Issue 4
Hlavní autor: Berkholz, Christoph
Médium: Journal Article
Jazyk:angličtina
Vydáno: Logical Methods in Computer Science e.V 08.10.2013
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ISSN:1860-5974, 1860-5974
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Shrnutí:The existential k-pebble game characterizes the expressive power of the existential-positive k-variable fragment of first-order logic on finite structures. The winner of the existential k-pebble game on two given finite structures can be determined in time O(n2k) by dynamic programming on the graph of game configurations. We show that there is no O(n(k-3)/12)-time algorithm that decides which player can win the existential k-pebble game on two given structures. This lower bound is unconditional and does not rely on any complexity-theoretic assumptions. Establishing strong k-consistency is a well-known heuristic for solving the constraint satisfaction problem (CSP). By the game characterization of Kolaitis and Vardi our result implies that there is no O(n(k-3)/12)-time algorithm that decides if strong k-consistency can be established for a given CSP-instance.
ISSN:1860-5974
1860-5974
DOI:10.2168/LMCS-9(4:2)2013