ThmDex – An index of mathematical definitions, results, and conjectures.

▼	Set of symbols
▼	Propositional connective
▼	Set of propositional connectives
▼	Complete set of propositional connectives
▼	Set of propositional symbols
▼	Set of predicate symbols
▼	Set-theoretic alphabet
▼	Set-theoretic language
▼	Set-theoretic expression

Definition D908

Set-theoretic formula