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Circuit complexity and decompositions of global constraints


Christian Bessiere, Georgios Katsirelos, Nina Narodytska and Toby Walsh






We show that tools from circuit complexity can be used to study decompositions of global constraints. In particular, we study decompositions of global constraints into conjunctive normal form with the property that unit propagation on the decomposition enforces the same level of consistency as a specialized propagation algorithm. We prove that a constraint propagator has a a polynomial size decomposition if and only if it can be computed by a polynomial size monotone Boolean circuit. Lower bounds on the size of monotone Boolean circuits thus translate to lower bounds on the size of decompositions of global constraints. For instance, we prove that there is no polynomial sized decomposition of the domain consistency propagator for the \alldiff constraint.

BibTeX Entry

    author           = {Bessiere, Christian and Katsirelos, Georgios and Narodytska, Nina and Walsh, Toby},
    month            = jul,
    year             = {2009},
    keywords         = {constraint satisfaction, satisfiability, circuit complexity},
    title            = {Circuit Complexity and Decompositions of Global Constraints},
    booktitle        = {International Joint Conference on Artificial Intelligence IJCAI-09},
    address          = {Pasadena, CA, USA}


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