Theorem clelsb1 2270

Description: Substitution for the first argument of the membership predicate in an atomic formula (class version of elsb1 2143). (Contributed by Rodolfo Medina, 28-Apr-2010.) (Proof shortened by Andrew Salmon, 14-Jun-2011.)

Assertion

Ref	Expression
clelsb1	|- ( [ y / x ] x e. A <-> y e. A )

Distinct variable group:   x, A

Allowed substitution hint:   A( y)

Proof of Theorem clelsb1

Dummy variable w is distinct from all other variables.

Step	Hyp	Ref	Expression
1		nfv 1516	. . 3 |- F/ x w e. A
2	1	sbco2 1953	. 2 |- ( [ y / x ] [ x / w ] w e. A <-> [ y / w ] w e. A )
3		nfv 1516	. . . 4 |- F/ w x e. A
4		eleq1 2228	. . . 4 |- ( w = x -> ( w e. A <-> x e. A ) )
5	3, 4	sbie 1779	. . 3 |- ( [ x / w ] w e. A <-> x e. A )
6	5	sbbii 1753	. 2 |- ( [ y / x ] [ x / w ] w e. A <-> [ y / x ] x e. A )
7		nfv 1516	. . 3 |- F/ w y e. A
8		eleq1 2228	. . 3 |- ( w = y -> ( w e. A <-> y e. A ) )
9	7, 8	sbie 1779	. 2 |- ( [ y / w ] w e. A <-> y e. A )
10	2, 6, 9	3bitr3i 209	1 |- ( [ y / x ] x e. A <-> y e. A )

Syntax hints:   <-> wb 104   [wsb 1750   e. wcel 2136

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 699  ax-5 1435  ax-7 1436  ax-gen 1437  ax-ie1 1481  ax-ie2 1482  ax-8 1492  ax-10 1493  ax-11 1494  ax-i12 1495  ax-bndl 1497  ax-4 1498  ax-17 1514  ax-i9 1518  ax-ial 1522  ax-i5r 1523  ax-ext 2147

This theorem depends on definitions:  df-bi 116  df-nf 1449  df-sb 1751  df-cleq 2158  df-clel 2161

This theorem is referenced by:  hblem  2273  nfraldya  2500  nfrexdya  2501  cbvreu  2689  sbcel1v  3012  rmo3  3041  setindel  4514  elirr  4517  en2lp  4530  zfregfr  4550  tfi  4558  bdcriota  13725