This paper engages in a mathematical investigation of generalized hypertree width, a structural measure that has up to recently eluded study, and obtains a number of computational results, including a simple proof of the tractability of CSP instances having bounded generalizedhypertree width.Expand

This work systematically study the complexity of planning restricted by the causal graph, and gives a complete classification theorem on causal graphs, showing that a set of graphs is either polynomial-time tractable, or is not polynomially tractable unless an established complexity-theoretic assumption fails.Expand

A viewpoint on the research program of understanding the complexity of the problems QCSP( B ) on finite structures is offered and a group of conjectures are proposed and discussed.Expand

This work defines and study a general model for generating random QBF instances, and exhibits experimental results showing that the model bears certain desirable similarities to the random SAT model, as well as a number of theoretical results concerning the model.Expand

This work presents and studies a framework in which one can present alternation-based lower bounds on proof length in proof systems for quantified Boolean formulas and introduces a proof system ensemble called relaxing QU-res that is based on the established proof system QU-resolution.Expand

The quantified constraint satisfaction framework is used to study how the complexity of deciding such a game depends on the parameter set of allowed predicates, and it is shown that the complexity is determined by the surjective polymorphisms of the constraint predicates.Expand

A QCSP tractability result arising from variable-based restrictions is presented by giving a polynomial time algorithm for certain classes of QCSP instances having bounded treewidth.Expand

The constraint satisfaction probem (CSP) is a well-acknowledged framework in which many combinatorial search problems can be naturally formulated. The CSP may be viewed as the problem of deciding the… Expand

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This article systematically studies—for various classes of polymorphisms—the computational complexity of deciding whether or not a given structure ℍ admits a polymorphism from the class, and proves the NP-completeness of deciding a condition conjectured to characterize the tractable problems CSP(ℍ).Expand