# Quantifier

The general name for a logical operation that constructs from a predicate a statement characterizing the domain of validity of . In mathematical logic, the most widely used quantifiers are the universal quantifier and the existential quantifier . The statement means that the domain of validity of is the same as the domain of values of the variable . The statement means that the domain of validity of is non-empty. If one is interested in the behaviour of the predicate not on the whole domain of values of , but only on the part singled out by a predicate , then one often uses the restricted quantifiers and . In this case, the statement means the same as , while has the same meaning as , where is the conjunction sign and is the implication sign.