An Etymological Dictionary of Astronomy and Astrophysics
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A symbol of → predicate logic which expresses that the statements within its scope are → true for at least one instance of something. The symbol ∃ is used as the existential quantifier. Existential quantifiers are normally used in logic in → conjunction with → predicate symbols, which say something about a → variable or → constant, in this case the variable being quantified (→ quantify, → quantification).

→ existential; → quantifier.

1) 1) A word that indicates the quantity of something.
2) Math.: A phrase in a logical expression that somehow specifies the quantity of variables. In particular either of the phrases "for all" (written symbolically as ∀) and "there exists" (∃).
3) In → predicate logic, a symbol that applies to, or binds, → variables which represent the → arguments of → predicates. See also → existential quantifier and → universal quantifier. In → first-order logic theses variables must range over → individuals. In higher-order logics they may range over predicates.

Agent noun of → quantify

A symbol of → predicate logic which expresses that the statements within its scope are → true for everything, or every instance of a specific thing. The symbol ∀ "for all" is used as the universal quantifier. Universal quantifiers are normally used in logic in conjunction with predicate symbols, which say something about a variable or constant, in this case the variable being quantified.

→ universal; → quantifier.