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 Drescher, Christian


Conflict-Driven Constraint Answer Set Solving with Lazy Nogood Generation

AAAI Conferences

Drescher and Walsh, to satisfiability modulo theories, the key idea is to incorporate 2010). Then, constraint answer sets of the resulting program theory-specific predicates into propositional formulas, can be characterized via Boolean assignments over and extending an ASP solver's decision engine for a atom(ฮ ) body(ฮ ) that do not violate a set of nogoods more high-level proof procedure. A promising approach to imposed by ฮ . Formally, a Boolean assignment A is a sequence constraint answer set programming (CASP) has been presented (ฯƒ


Translation-based Constraint Answer Set Solving

arXiv.org Artificial Intelligence

We solve constraint satisfaction problems through translation to answer set programming (ASP). Our reformulations have the property that unit-propagation in the ASP solver achieves well defined local consistency properties like arc, bound and range consistency. Experiments demonstrate the computational value of this approach.


Heuristics in Conflict Resolution

arXiv.org Artificial Intelligence

Modern solvers for Boolean Satisfiability (SAT) and Answer Set Programming (ASP) are based on sophisticated Boolean constraint solving techniques. In both areas, conflict-driven learning and related techniques constitute key features whose application is enabled by conflict analysis. Although various conflict analysis schemes have been proposed, implemented, and studied both theoretically and practically in the SAT area, the heuristic aspects involved in conflict analysis have not yet received much attention. Assuming a fixed conflict analysis scheme, we address the open question of how to identify "good'' reasons for conflicts, and we investigate several heuristics for conflict analysis in ASP solving. To our knowledge, a systematic study like ours has not yet been performed in the SAT area, thus, it might be beneficial for both the field of ASP as well as the one of SAT solving.