Quantifier

2 definitions found

From WordNet (r) 2.0 [wn]:

  quantifier
       n 1: (logic) a word (such as `some' or `all' or `no') that binds
            the variables in a logical proposition [syn: {logical
            quantifier}]
       2: (grammar) a word that expresses a quantity (as `fifteen' or
          `many')



From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  quantifier
       
           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}.
       
          (2002-05-21)