A greedy local search procedure called GSAT is introduced for solving propositional satisfiability problems and its good performance suggests that it may be advantageous to reformulate reasoning tasks that have traditionally been viewed as theorem-proving problems as model-finding tasks.Expand

It is shown that by using the right distribution of instances, and appropriate parameter values, it is possible to generate random formulas that are hard, that is, for which satisfiability testing is quite difficult.Expand

It is shown that by using the right distribution of instances, and appropriate parameter values, it is possible to generate random formulas that are hard, that is, for which satisfiability testing is quite difficult.Expand

The performance of the most popular SAT algorithms on random problems, the theory of average case complexity, the threshold phenomenon, known lower bounds for certain classes of algorithms, and the problem of generating hard instances with solutions are considered.Expand

A declarative constraint programming framework is proposed which is based on the classical notion of extension of a structure by new relations, and properties of the formal framework intended to support effective modelling, and prospects for effective solver design.Expand

An analysis that shows why deciding satisfiability of instances from some distributions is challenging for current complete methods is presented, and shows that when constraints are not too tight almost all unsatisfiable instances have a structural property which guarantees that unsatisfiability proofs in a certain resolution-like system must be of exponential size.Expand

A "lifted" version of unit propagation which may be carried out prior to grounding is defined, and integration of the resulting technique into grounding algorithms is described and an experimental study of its performance is described.Expand

A natural branching strategy with which backtracking with 2-way branching finds refutations of these instances in time O(d2n2) is given, and exponential separations between C-RES and NG-RES, as well as between the tree-like and unrestricted versions of each system are shown.Expand

We report results from large-scale experiments in satissability testing. As has been observed by others, testing the satissability of random formulas often appears surprisingly easy. Here we show… Expand

Constraint satisfaction provides a uniform framework for addressing a variety of combinatorial problems. Propositional proof complexity is the study of the minimum lengths of proofs in propositional… Expand