Existential quantifier is a logical operator of predicate logic, written ThereIs, which makes it possible to express that at least one entity in the universe of discourse has a particular property.
in (i), ThereIs is used to express that there is at least one entity x which has property P:
(i) ThereIs(x) [ P(x) ]
The existential quantifier can be used to represent the meaning of indefinite noun phrases:
(ii) John ate a donut ThereIs(x) [ donut(x) & ate(john,x) ]
- Gamut, L.T.F. 1991. Logic, language, and meaning, Univ. of Chicago Press, Chicago.