∃

The existential quantifier, also known as "there exists" and "for some." The proposition ∃x P(x) translates into English as "for some x P(x)", "there is an x such that P(x)", or "there is at least one x such that P(x)".

It means that P(x) is true for at least one element x in the universe of discourse (the domain under consideration). Used extensively in logic.