Theorem equidqe 1466

Description: equid 1630 with some quantification and negation without using ax-4 1441 or ax-17 1460. (Contributed by NM, 13-Jan-2011.) (Proof shortened by Wolf Lammen, 27-Feb-2014.)

Assertion

Ref	Expression
equidqe	|- -. A. y -. x = x

Proof of Theorem equidqe

Step	Hyp	Ref	Expression
1		ax-9 1465	. 2 |- -. A. y -. y = x
2		ax-8 1436	. . . . 5 |- ( y = x -> ( y = x -> x = x ) )
3	2	pm2.43i 48	. . . 4 |- ( y = x -> x = x )
4	3	con3i 595	. . 3 |- ( -. x = x -> -. y = x )
5	4	alimi 1385	. 2 |- ( A. y -. x = x -> A. y -. y = x )
6	1, 5	mto 621	1 |- -. A. y -. x = x

Syntax hints:   -. wn 3   A.wal 1283

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 577  ax-in2 578  ax-5 1377  ax-gen 1379  ax-ie2 1424  ax-8 1436  ax-i9 1464

This theorem depends on definitions:  df-bi 115  df-tru 1288  df-fal 1291

This theorem is referenced by:  ax4sp1  1467