Theorem dral1 1658

Description: Formula-building lemma for use with the Distinctor Reduction Theorem. Part of Theorem 9.4 of [Megill] p. 448 (p. 16 of preprint). (Contributed by NM, 24-Nov-1994.)

Hypothesis

Ref	Expression
dral1.1	|- ( A. x x = y -> ( ph <-> ps ) )

Assertion

Ref	Expression
dral1	|- ( A. x x = y -> ( A. x ph <-> A. y ps ) )

Proof of Theorem dral1

Step	Hyp	Ref	Expression
1		hbae 1646	. . . 4 |- ( A. x x = y -> A. x A. x x = y )
2		dral1.1	. . . . 5 |- ( A. x x = y -> ( ph <-> ps ) )
3	2	biimpd 142	. . . 4 |- ( A. x x = y -> ( ph -> ps ) )
4	1, 3	alimdh 1396	. . 3 |- ( A. x x = y -> ( A. x ph -> A. x ps ) )
5		ax10o 1643	. . 3 |- ( A. x x = y -> ( A. x ps -> A. y ps ) )
6	4, 5	syld 44	. 2 |- ( A. x x = y -> ( A. x ph -> A. y ps ) )
7		hbae 1646	. . . 4 |- ( A. x x = y -> A. y A. x x = y )
8	2	biimprd 156	. . . 4 |- ( A. x x = y -> ( ps -> ph ) )
9	7, 8	alimdh 1396	. . 3 |- ( A. x x = y -> ( A. y ps -> A. y ph ) )
10		ax10o 1643	. . . 4 |- ( A. y y = x -> ( A. y ph -> A. x ph ) )
11	10	alequcoms 1449	. . 3 |- ( A. x x = y -> ( A. y ph -> A. x ph ) )
12	9, 11	syld 44	. 2 |- ( A. x x = y -> ( A. y ps -> A. x ph ) )
13	6, 12	impbid 127	1 |- ( A. x x = y -> ( A. x ph <-> A. y ps ) )

Syntax hints:   -> wi 4   <-> wb 103   A.wal 1282

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-io 662  ax-5 1376  ax-7 1377  ax-gen 1378  ax-ie2 1423  ax-8 1435  ax-10 1436  ax-11 1437  ax-i12 1438  ax-4 1440  ax-17 1459  ax-i9 1463  ax-ial 1467

This theorem depends on definitions:  df-bi 115

This theorem is referenced by:  drnf1  1661  equveli  1682  a16g  1785