enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Negation - Wikipedia

    en.wikipedia.org/wiki/Negation

    In logic, negation, also called the logical not or logical complement, is an operation that takes a proposition to another proposition "not ", written , , ...

  3. Boolean satisfiability problem - Wikipedia

    en.wikipedia.org/wiki/Boolean_satisfiability_problem

    In logic and computer science, the Boolean satisfiability problem [a] asks if there exists an interpretation that satisfies a given Boolean formula. In other words, it asks can a Boolean formula's variables be assigned TRUE or FALSE to make the formula TRUE. If this is the case, the formula is called satisfiable, else it is unsatisfiable.

  4. Stable model semantics - Wikipedia

    en.wikipedia.org/wiki/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.

  5. Proof by contradiction - Wikipedia

    en.wikipedia.org/wiki/Proof_by_contradiction

    Its negation ¬H(M) states that "M neither halts nor does not halt", which is false by the law of noncontradiction (which is intuitionistically valid). If proof by contradiction were intuitionistically valid, we would obtain an algorithm for deciding whether an arbitrary Turing machine M halts, thereby violating the (intuitionistically valid ...

  6. Negation as failure - Wikipedia

    en.wikipedia.org/wiki/Negation_as_failure

    Negation As Failure (NAF, for short) is a non-monotonic inference rule in logic programming, used to derive (i.e. that is assumed not to hold) from failure to derive . Note that n o t p {\displaystyle \mathrm {not} ~p} can be different from the statement ¬ p {\displaystyle \neg p} of the logical negation of p {\displaystyle p} , depending on ...

  7. Material conditional - Wikipedia

    en.wikipedia.org/wiki/Material_conditional

    Due to the paradoxes of material implication and related problems, ... is not a propositional theorem, but the material conditional is used to define negation. ...

  8. Law of excluded middle - Wikipedia

    en.wikipedia.org/wiki/Law_of_excluded_middle

    In logic, the law of excluded middle or the principle of excluded middle states that for every proposition, either this proposition or its negation is true. [1] [2] It is one of the three laws of thought, along with the law of noncontradiction, and the law of identity; however, no system of logic is built on just these laws, and none of these laws provides inference rules, such as modus ponens ...

  9. Double negation - Wikipedia

    en.wikipedia.org/wiki/Double_negation

    In propositional logic, the double negation of a statement states that "it is not the case that the statement is not true". In classical logic, every statement is logically equivalent to its double negation, but this is not true in intuitionistic logic; this can be expressed by the formula A ≡ ~(~A) where the sign ≡ expresses logical equivalence and the sign ~ expresses negation.