PASCAL - Pattern Analysis, Statistical Modelling and Computational Learning

On the power of k-consistency
Albert Atserias, Andrei Bulatov and Victor Dalmau
In: Automata, Languages and Programming, 34th International Colloquium, ICALP 2007(2007).

Abstract

The k-consistency algorithm for constraint satisfaction proceeds, roughtly, by finding all partial solutions on at most k variables and iteratively deleting those that cannot be extended to a partial solution by one more variable. It is known that if the core of the structure encoding the scopes of the constraints has treewidth at most k, then the k-consistency algorithm is always correct. We prove the exact converse to this: if the core of the structure encoding the scopes of the constraints does not have treewidth at most k, then the k-consistency algorithm is not always correct. This characterizes the exact power of the k-consistency algorithm in structural terms.

EPrint Type:Conference or Workshop Item (Paper)
Project Keyword:Project Keyword UNSPECIFIED
Subjects:Theory & Algorithms
ID Code:5286
Deposited By:Victor Dalmau
Deposited On:24 March 2009