Theorem clelsb2 2281

Description: Substitution for the second argument of the membership predicate in an atomic formula (class version of elsb2 2154). (Contributed by Jim Kingdon, 22-Nov-2018.)

Assertion

Ref	Expression
clelsb2	|- ( [ y / x ] A e. x <-> A e. y )

Distinct variable group:   x, A

Allowed substitution hint:   A( y)

Proof of Theorem clelsb2

Dummy variable w is distinct from all other variables.

Step	Hyp	Ref	Expression
1		nfv 1526	. . 3 |- F/ x A e. w
2	1	sbco2 1963	. 2 |- ( [ y / x ] [ x / w ] A e. w <-> [ y / w ] A e. w )
3		nfv 1526	. . . 4 |- F/ w A e. x
4		eleq2 2239	. . . 4 |- ( w = x -> ( A e. w <-> A e. x ) )
5	3, 4	sbie 1789	. . 3 |- ( [ x / w ] A e. w <-> A e. x )
6	5	sbbii 1763	. 2 |- ( [ y / x ] [ x / w ] A e. w <-> [ y / x ] A e. x )
7		nfv 1526	. . 3 |- F/ w A e. y
8		eleq2 2239	. . 3 |- ( w = y -> ( A e. w <-> A e. y ) )
9	7, 8	sbie 1789	. 2 |- ( [ y / w ] A e. w <-> A e. y )
10	2, 6, 9	3bitr3i 210	1 |- ( [ y / x ] A e. x <-> A e. y )

Syntax hints:   <-> wb 105   [wsb 1760   e. wcel 2146

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 709  ax-5 1445  ax-7 1446  ax-gen 1447  ax-ie1 1491  ax-ie2 1492  ax-8 1502  ax-10 1503  ax-11 1504  ax-i12 1505  ax-bndl 1507  ax-4 1508  ax-17 1524  ax-i9 1528  ax-ial 1532  ax-i5r 1533  ax-ext 2157

This theorem depends on definitions:  df-bi 117  df-nf 1459  df-sb 1761  df-cleq 2168  df-clel 2171

This theorem is referenced by:  peano1  4587  peano2  4588