ThmDex – An index of mathematical definitions, results, and conjectures.
Formulation F10573 on R4541: Open set is its own interior
F10573
Formulation 0
Let $T = (X, \mathcal{T})$ be a D1106: Topological space such that
(i) $U \in \mathcal{T}$ is an D97: Open set in $T$
Then \begin{equation} \text{int} \langle U \rangle = U \end{equation}