ThmDex – An index of mathematical definitions, results, and conjectures.

ThmDex – An index of mathematical definitions, results, and conjectures.

Result R4000 on D2640: Clopen set

Empty set is clopen

Formulation 0

Let $T = (X, \mathcal{T})$ be a D1106: Topological space.

Then $\emptyset$ is a D2640: Clopen set in $T$.