ThmDex – An index of mathematical definitions, results, and conjectures.
Result R4160 on D76: Set intersection
Subset of intersection iff subset of every set in the intersection
Formulation 0
Let $X$ be a D11: Set.
Let $E_j$ be a D11: Set for each $j \in J$ such that
(i) $\bigcap_{j \in J} E_j$ is the D76: Set intersection of $E = \{ E_j \}_{j \in J}$
Then \begin{equation} X \subseteq \bigcap_{j \in J} E_j \quad \iff \quad \forall \, j \in J : X \subseteq E_j \end{equation}