Regular topological space/Definition
From Maths
Definition
A topological space, [ilmath](X,\mathcal{ J })[/ilmath] is regular if[1]:
- [ilmath]\forall E\in C(\mathcal{J})\ \forall x\in X-E\ \exists U,V\in\mathcal{J}[U\cap V=\emptyset\implies(E\subset U\wedge x\in V)][/ilmath] - (here [ilmath]C(\mathcal{J})[/ilmath] denotes the closed sets of the topology [ilmath]\mathcal{J} [/ilmath])
Warning:Note that it is [ilmath]E\subset U[/ilmath] not [ilmath]\subseteq[/ilmath], the author ([1]) like me is pedantic about this, so it must matter
