Metamath Proof Explorer


Theorem regr1

Description: A regular space is R_1, which means that any two topologically distinct points can be separated by neighborhoods. (Contributed by Mario Carneiro, 25-Aug-2015)

Ref Expression
Assertion regr1 J Reg KQ J Haus

Proof

Step Hyp Ref Expression
1 regtop J Reg J Top
2 toptopon2 J Top J TopOn J
3 1 2 sylib J Reg J TopOn J
4 eqid x J y J | x y = x J y J | x y
5 4 regr1lem2 J TopOn J J Reg KQ J Haus
6 3 5 mpancom J Reg KQ J Haus