Theorem rexnalOLD 2906

Description: Obsolete proof of rexnal 2905 as of 26-Nov-2019. (Contributed by NM, 21-Jan-1997.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
rexnalOLD

Proof of Theorem rexnalOLD

Step	Hyp	Ref	Expression
1		df-rex 2813	. 2
2		exanali 1670	. . 3
3		df-ral 2812	. . 3
4	2, 3	xchbinxr 311	. 2
5	1, 4	bitri 249	1

Syntax hints:  -.wn 3  ->wi 4  <->wb 184  /\wa 369  A.wal 1393  E.wex 1612  e.wcel 1818  A.wral 2807  E.wrex 2808

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1618  ax-4 1631

This theorem depends on definitions:  df-bi 185  df-an 371  df-ex 1613  df-ral 2812  df-rex 2813