ThmDex – An index of mathematical definitions, results, and conjectures.
Intersection is a lower bound to each set in the intersection
Formulation 0
Let $E_j$ be a D11: Set for each $j \in J$ such that
(i) $\bigcap_{j \in J} E_j$ is a D76: Set intersection for $\{ E_j \}_{j \in J}$
Then \begin{equation} \forall \, i \in J : \bigcap_{j \in J} E_j \subseteq E_i \end{equation}
Formulation 1
Let $E_j$ be a D11: Set for each $j \in J$ such that
(i) $\cap E$ is a D76: Set intersection for $E = \{ E_j \}_{j \in J}$
Then \begin{equation} \forall \, j \in J : \cap E \subseteq E_j \end{equation}
Subresults
R4149: Countable intersection is a lower bound to each set in the intersection
Proofs
Proof 0
Let $E_j$ be a D11: Set for each $j \in J$ such that
(i) $\bigcap_{j \in J} E_j$ is a D76: Set intersection for $\{ E_j \}_{j \in J}$
This result is a particular case of R1130: Intersection is largest lower bound. $\square$