Metamath Proof Explorer


Axiom ax-9d1

Description: Distinct variable version of ax-6 , equal variables case. (Contributed by Mario Carneiro, 14-Aug-2015)

Ref Expression
Assertion ax-9d1 ¬x¬x=x

Detailed syntax breakdown

Step Hyp Ref Expression
0 vx setvarx
1 0 cv setvarx
2 1 1 wceq wffx=x
3 2 wn wff¬x=x
4 3 0 wal wffx¬x=x
5 4 wn wff¬x¬x=x