ThmDex – An index of mathematical definitions, results, and conjectures.
F13326
Formulation 1
Let $E_1, \, \ldots, \, E_N$ each be a D11: Set such that
(i) $\cup E$ is a D77: Set union for $E = (E_1, \, \ldots, \, E_N)$
Then \begin{equation} E_1 \subseteq \cup E, \quad E_2 \subseteq \cup E, \quad \ldots, \quad E_N \subseteq \cup E \end{equation}