▾ Set of symbols
▾ Alphabet
▾ Deduction system
▾ Theory
▾ Zermelo-Fraenkel set theory
▾ Set
▾ Subset
▾ Superset
Proper superset
Formulation 0
Let $E$ be a D11: Set.
A D11: Set $X$ is a proper superset of $E$ if and only if
(1) $\forall \, x \in E : x \in X$ (D954: Superset)
(2) $E \neq X$