منابع مشابه
Horn Clauses Queries and Generalizations
D A logic program consists of a set of Horn clauses, and can be used to express a query on relational data bases. It is shown that logic programs express precisely the queries in YE+ (the set of queries representable by a fixpoint applied to a positive existential query). Queries expressible by logic programs are thus not first-order queries in general, nor are all the first-order queries expre...
متن کاملSmallest Horn Clause Programs
The simplest non{trivial program pattern in logic programming is the following one : 8 < : p(fact) : p(left) p(right) : p(goal) : where fact, goal, left and right are arbitrary terms. Because the well known append program matches this pattern, we will denote such programs \append{like". In spite of their simple appearance, we prove in this paper that termination and satissability (i.e the exist...
متن کاملGeneralized Horn Clause Programs
This paper considers, in a general setting, an axiomatic basis for Horn clause logic programming. It characterizes a variety of \Horn-clause-like" computations, arising in contexts such as deductive databases, various abstract interpretations, and extensions to logic programming involving E-uniication, quantitative deduction, and inheritance, in terms of two simple operators , and discusses alg...
متن کاملHorn Clause Contraction Functions
In classical, AGM-style belief change, it is assumed that the underlying logic contains classical propositional logic. This is clearly a limiting assumption, particularly in Artificial Intelligence. Consequently there has been recent interest in studying belief change in approaches where the full expressivity of classical propositional logic is not obtained. In this paper we investigate belief ...
متن کاملProbabilistic Horn Clause Verification
Constrained Horn clauses have proven to be a natural intermediate language for logically characterizing program semantics and reasoning about program behavior. In this paper, we present probabilistically constrained Horn clauses (pchc), which incorporate probabilistic variables inside otherwise traditional constrained Horn clauses. pchc enable reasoning about probabilistic programs by encoding ...
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ژورنال
عنوان ژورنال: The Journal of Logic Programming
سال: 1985
ISSN: 0743-1066
DOI: 10.1016/0743-1066(85)90002-0