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Full-Text Articles in Physical Sciences and Mathematics
The Complexity Of Local Stratification, Peter Cholak, Howard A. Blair
The Complexity Of Local Stratification, Peter Cholak, Howard A. Blair
Electrical Engineering and Computer Science - Technical Reports
The class of locally stratified logic programs is shown to be Π11-complete by the construction of a reducibility of the class of infinitely branching nondeterministic finite register machines.nondeterministic finite register machines.
A Unified Framework For Three-Valued Semantical Treatments Of Logic Programming, Feng Yang
A Unified Framework For Three-Valued Semantical Treatments Of Logic Programming, Feng Yang
Electrical Engineering and Computer Science - Technical Reports
Based on Fiting's Φ operator a unified framework for three-valued semantics of logic programming is presented. The truth space used in the framework is the class of partial interpretations. Underlying the truth space is two partial orderings, knowledge ordering and truth ordering. It turns out that the truth space with the truth ordering is a complete lattice and the truth space with knowledge ordering is a semi-complete lattice. Φ is proved to be continuous over the complete lattice and monotonic over the semi-complete lattice. With the use of Φ operator two well-known three-valued semantics for logic programming, Fitting's three-valued semantics …
Duality In Logic Programming, Feng Yang
Duality In Logic Programming, Feng Yang
Electrical Engineering and Computer Science - Technical Reports
Various approximations of classic negation have been proposed for logic programming. But the semantics for those approximations are not entirely clear. In this paper a proof-theoretic operator, we call it failure operator, denoted as FP, is associated with each logic program to characterize the meaning of various negations in logic programming. It is shown that the failure operator FP is a dual of the TP, immediate consequence operator developed by Van Emden and Kowalski and is downward continuous. It has the desirable properties entirely analogous to what TP has such as continuity, having a unique least fixpoint and a unique …