Preprocessing of CNF formulas is an invaluable technique when attempting to solve large formulas, such as those that model industrial verification problems. Unfortunately, the best combination of preprocessing techniques, which involve variable elimination combined with subsumption, is incompatible with incremental satisfiability. The reason is that soundness is lost if a variable is eliminated...

Correspondences in ontology alignments relate two ontology entities with a relation. Typical relations are equivalence or subsumption. However, different systems may need different kinds of relations. We propose to use the concepts of algebra of relations in order to express the relations between ontology entities in a general way. We show the benefits in doing so in expressing disjunctive rela...

Abstract. We develop and analyze clause elimination procedures, a specific family of simplification techniques for conjunctive normal form (CNF) formulas. Extending known procedures such as tautology, subsumption, and blocked clause elimination, we introduce novel elimination procedures based on hidden and asymmetric variants of these techniques. We analyze the resulting nine (including five ne...

This paper presents C-CLASSIC , a Description Logic (DL) which is expressive enough to be practically useful and which can handle default knowledge. C-CLASSIC has been given an intensional semantics (CL) in which concepts are denoted by a normal form of the set of their properties (rather than the set of their instances as is the case in model-theoric semantics). Therefore, the subsumption algo...

Useful equivalence-preserving operations based on unfilinks are described. These operations eliminate a potentially large number of subsumed paths in a negation normal form formula. Those anti-links that directly indicate the presence of subsumed paths are characterized. These operations are useful for prime implicant/implicate algorithms because most of the computational effort in computing th...

 Abstract Background: Radiography is the most widely available imaging modality. Precise evaluations of wrist x-ray can help diagnosis and evaluate the prognosis of many wrist disorders. Methods: We measured length, angles and indices in 150 posteroanterior and lateral wrist x-rays to determine normal dimensions and variations according to age and sex. All x-rays were made with standar...

According to the several scientific resources, Iran is considered to be among the melioidosis-endemic regions of the world; this is in stark contrast to the domestic stance in Iran, where the risk of melioidosis is speculated only as an emerging infectious disease in a non-endemic area. Recently, we have had devastating flash floods in the most provinces of Iran; the changing of soil structure ...