where <math>A,B_{1},\dots,B_{m},C_{1},\dots,C_{n}</math> are ground atoms.
;''Head atoms:'': If an atom <math>{{mvar|A</math>}} belongs to a stable model of a logic program <math>{{mvar|P</math>}} then <math>{{mvar|A</math>}} is the head of one of the rules of <math>{{mvar|P</math>}}.
;''Minimality:'': Any stable model of a logic program <math>{{mvar|P</math>}} is minimal among the models of <math>{{mvar|P</math>}} relative to set inclusion.
;''The antichain property:'': If <math>{{mvar|I</math>}} and <math>{{mvar|J</math>}} are stable models of the same logic program then <math>{{mvar|I</math>}} is not a proper subset of <math>{{mvar|J</math>}}. In other words, the set of stable models of a program is an [[antichain]].
;''NP-completeness:'': Testing whether a finite ground logic program has a stable model is [[NP-complete]].
==Relation to other theories of negation as failure==
