Conflict analysis

Abstract: This paper introduces GRASP (Generic seaRch Algorithm for the Satisfiability Problem), an integrated algorithmic framework for SAT that unifies several previously proposed search-pruning techniques and facilitates identification of additional ones. GRASP is premised on the inevitability of conflicts during search and its most distinguishing feature is the augmentation of basic backtracking search with a powerful conflict analysis procedure. Analyzing conflicts to determine their causes enables GRASP to backtrack non-chronologically to earlier levels in the search tree, potentially pruning large portions of the search space. In addition, by "recording" the causes of conflicts, GRASP can recognize and preempt the occurrence of similar conflicts later on in the search. Finally, straightforward bookkeeping of the causality chains leading up to conflicts allows GRASP to identify assignments that are necessary for a solution to be found. Experimental results obtained from a large number of benchmarks, including many from the field of test pattern generation, indicate that application of the proposed conflict analysis techniques to SAT algorithms can be extremely effective for a large number of representative classes of SAT instances.

Abstract: of distinguished and rather senior economists – makes at the end of the book. Their priorities tend to be quick-fixes of problems that might, at least partly, be caused by some other challenge. More importantly, the panellists tend to disregard some of the evidence assembled by the authors. The reactions to the excellent chapter on armed conflict by Collier & Hoeffler illustrate that Nobel awards are no protection against bias. One member of the panel dismisses the economic sources of war that the Oxford economists analyse and points out that free trade is the main pacifying force, while another famous panellist mentions ethnic or religious hatred as a source of conflict. Gerald Schneider