scholarly journals Generic CDCL -- A Formalization of Modern Propositional Satisfiability Solvers

10.29007/7n71 ◽  
2018 ◽  
Author(s):  
Steffen Hölldobler ◽  
Norbert Manthey ◽  
Tobias Philipp ◽  
Peter Steinke

Modern propositional satisfiability (or SAT) solvers are very powerful due to recent developments on the underlying data structures, the used heuristics to guide the search, the deduction techniques to infer knowledge, and the formula simplification techniques that are used during pre- and inprocessing. However, when all these techniques are put together, the soundness of the combined algorithm is not guaranteed any more, and understanding the complex dependencies becomes non-trivial.In this paper we present a small set of rules that allows to model modern SAT solvers in terms of a state transition system. With these rules all techniques which are applied in modern SAT solvers can be modeled adequately. Furthermore, we show that this set of rules results is sound, complete and confluent. Finnaly, we compare the proposed transition system to related systems, and show how widely used solving techniques can be modeled.


Author(s):  
EUGENIO DI SCIASCIO ◽  
FRANCESCO M. DONINI ◽  
MARINA MONGIELLO

Web engines crawl hyperlinks to search for new documents; yet when they index discovered documents they basically revert to conventional information retrieval models and concentrate on the indexing of terms in a single document. We propose to overcome such limits with an approach based on temporal logic. By modeling a web site as a finite state transition system we are able to define complex and selective queries over hyperlinks with the aid of Computation Tree Logic operators. We deployed the proposed approach in a prototype system that allows users pose queries in natural language. Queries are automatically translated in Computation Tree Logic, and the answer returned by our system is a set of paths. Experiments carried out with the aid of human experts show improved retrieval effectiveness with respect to current search engines.



2018 ◽  
Vol 87 (6) ◽  
pp. 063709
Author(s):  
Makoto Naka ◽  
Eriko Mizoguchi ◽  
Joji Nasu ◽  
Sumio Ishihara


1992 ◽  
Vol 6 (1) ◽  
pp. 39-63 ◽  
Author(s):  
Simon S. Lam ◽  
A. Udaya Shankar








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