Theorem equidqe 34207

Description: equid 1939 with existential quantifier without using ax-c5 34168 or ax-5 1839. (Contributed by NM, 13-Jan-2011.) (Proof shortened by Wolf Lammen, 27-Feb-2014.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

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

Proof of Theorem equidqe

Step	Hyp	Ref	Expression
1		ax6fromc10 34181	. 2 |- -. A. y -. y = x
2		ax7 1943	. . . . 5 |- ( y = x -> ( y = x -> x = x ) )
3	2	pm2.43i 52	. . . 4 |- ( y = x -> x = x )
4	3	con3i 150	. . 3 |- ( -. x = x -> -. y = x )
5	4	alimi 1739	. 2 |- ( A. y -. x = x -> A. y -. y = x )
6	1, 5	mto 188	1 |- -. A. y -. x = x

Syntax hints:   -. wn 3   A.wal 1481

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-c7 34170  ax-c10 34171

This theorem depends on definitions:  df-bi 197  df-an 386  df-ex 1705

This theorem is referenced by:  axc5sp1  34208  equidq  34209