In predicate logic, an existential quantification is a type of quantifier, a logical constant which is interpreted as "there exists," "there is at least one," or "for some." It expresses that a propositional function can be satisfied by at least one member of a domain of discourse. In other terms, it is the predication of a property or relation to at least one member of the domain. It asserts that a predicate within the scope of an existential quantifier is true of at least one value of a predicate variable.
It is usually denoted by the turned E (∃) logical operator symbol, which, when used together with a predicate variable, is called an existential quantifier ("∃x" or "∃(x)"). Existential quantification is distinct from universal quantification ("for all"), which asserts that the property or relation holds for any members of the domain.
Symbols are encoded U+2203 ∃ there exists (HTML: ∃ ∃ as a mathematical symbol) and U+2204 ∄ there does not exist (HTML: ∄).
Read more about Existential Quantification: Basics
Famous quotes containing the word existential:
“One of the most horrible, yet most important, discoveries of our age has been that, if you really wish to destroy a person and turn him into an automaton, the surest method is not physical torture, in the strict sense, but simply to keep him awake, i.e., in an existential relation to life without intermission.”
—W.H. (Wystan Hugh)