翻訳と辞書
Words near each other
・ Stacey Hollywood
・ Stacey International
・ Stacey Jackson
・ Stacey Jones
・ Stacey Jordan
・ Stacey Kade
・ Stacey Katu
・ Stacey Keating
・ Stacey Kemp
・ Stable manifold theorem
・ Stable map
・ Stable marriage problem
・ Stable Master
・ Stable Mates
・ Stable model category
Stable model semantics
・ Stable module category
・ Stable normal bundle
・ Stable nucleic acid lipid particle
・ Stable nuclide
・ Stable ocean hypothesis
・ Stable on the Strand
・ Stable polynomial
・ Stable process
・ Stable range condition
・ Stable roommates problem
・ Stable set
・ Stable storage
・ Stable Strategies for Middle Management
・ Stable theory


Dictionary Lists
翻訳と辞書 辞書検索 [ 開発暫定版 ]
スポンサード リンク

Stable model semantics : ウィキペディア英語版
Stable model semantics
The concept of a stable model, or answer set, is used to define a declarative semantics for logic programs with negation as failure. This is one of several standard approaches to the meaning of negation in logic programming, along with program completion and the well-founded semantics. The stable model semantics is the basis of
answer set programming.
==Motivation==
Research on the declarative semantics of negation in logic programming was motivated by the fact that the behavior of SLDNF resolution—the generalization of SLD resolution used by Prolog in the presence of negation in the bodies of rules—does not fully match the truth tables familiar from classical propositional logic. Consider, for instance, the program
:p\
:r \leftarrow p,\ q
:s \leftarrow p,\ \hbox q.
Given this program, the query p will succeed, because the program includes p as a fact; the query q will fail, because it does not occur in the head of any of the rules. The query r will fail also, because the only rule with r in the head contains the subgoal q in its body; as we have seen, that subgoal fails. Finally, the query s succeeds, because each of the subgoals p, \hbox q succeeds. (The latter succeeds because the corresponding positive goal q fails.) To sum up, the behavior of SLDNF resolution on the given program can be represented by the following truth assignment:
On the other hand, the rules of the given program can be viewed as propositional formulas if we identify the comma with conjunction \land, the symbol \hbox with negation \neg, and agree to treat F \leftarrow G as the implication G \rightarrow F written backwards. For instance, the last rule of the given program is, from this point of view, alternative notation for the propositional formula
:p \land \neg q \rightarrow s.
If we calculate the truth values of the rules of the program for the truth
assignment shown above then we will see that each rule gets the value
T. In other words, that assignment is a model of the program. But this program has also other models, for instance
Thus one of the models of the given program is special in the sense that it correctly represents the behavior of SLDNF resolution. What are the mathematical properties of that model that make it special? An answer to this question is provided by the definition of a stable model.

抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)
ウィキペディアで「Stable model semantics」の詳細全文を読む



スポンサード リンク
翻訳と辞書 : 翻訳のためのインターネットリソース

Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.