# Quantifier

A quantifier is a logical operator which bounds a variable. Every quantifier must apply to some variable. Some examples of quantifiers include $\forall, \exists, \exists^\infty, \exists !, \exists^{=n}, Q, \star, \Box, \Diamond,$ and $\Delta^\sharp$. These roughly correspond to natural language quantifiers such as "all", "some", "exists finitely many", "probably exists".