Chuyển bộ gõ


Từ điển Máy Tính - Foldoc Dictionary
universal quantifier



quantifier

(logic)   An operator in predicate logic specifying for which values of a variable a formula is true. Universally quantified means "for all values" (written with an inverted A, LaTeX \forall) and existentially quantified means "there exists some value" (written with a reversed E, LaTeX \exists). To be unambiguous, the set to which the values of the variable belong should be specified, though this is often omitted when it is clear from the context (the "universe of discourse"). E.g.

 Forall x . P(x)  <=>  not (Exists x . not P(x)) 
meaning that any x (in some unspecified set) has property P which is equivalent to saying that there does not exist any x which does not have the property.

If a variable is not quantified then it is a free variable. In logic programming this usually means that it is actually universally quantified.

See also first order logic.

Last updated: 2002-05-21




Giới thiệu VNDIC.net | Plugin từ diển cho Firefox | Từ điển cho Toolbar IE | Tra cứu nhanh cho IE | Vndic bookmarklet | Học từ vựng | Vndic trên web của bạn

© Copyright 2006-2024 VNDIC.NET & VDICT.CO all rights reserved.