Revision as of 03:54, 3 December 2009 edit Gregbard (talk \| contribs) Extended confirmed users, Pending changes reviewers 90,738 edits →Motivation: truth value, Replaced: truth value → truth value, using Project:AWB ← Previous edit		Revision as of 04:10, 4 December 2009 edit undo Gregbard (talk \| contribs) Extended confirmed users, Pending changes reviewers 90,738 edits →Relation to other theories of negation as failure: tautology using AWB Next edit →
Line 227: :<math>p \leftarrow p</math> is the [[tautology (logic)\|tautology]] <math>p \leftrightarrow p</math>. The model <math>\emptyset</math> of this tautology is stable, but its other model <math>\{p\}\ </math> is not. François Fages [1994] found a syntactic condition on logic programs that eliminates such counterexamples and guarantees the stability of every model of the program's completion. The programs that satisfy his condition are called ''tight''. Fangzhen Lin and Yuting Zhao [2004] showed how to make the completion of a nontight program stronger so that all its nonstable models will be eliminated. The additional formulas that they add to the completion are called ''loop formulas''.

Stable model semantics: Difference between revisions