Theorem neirr 2521

Description: No class is unequal to itself. (Contributed by Stefan O'Rear, 1-Jan-2015.)

Assertion

Ref	Expression
neirr	|- -. A =/= A

Proof of Theorem neirr

Step	Hyp	Ref	Expression
1		eqid 2353	. 2 |- A = A
2		nne 2520	. 2 |- (-. A =/= A <-> A = A)
3	1, 2	mpbir 200	1 |- -. A =/= A

Syntax hints:  -. wn 3   = wceq 1642   =/= wne 2516

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-cleq 2346  df-ne 2518

This theorem is referenced by:  neldifsn  3841  ltcirr  6272