Theorem cbvab 2331

Description: Rule used to change bound variables, using implicit substitution. (Contributed by Andrew Salmon, 11-Jul-2011.)

Hypotheses

Ref	Expression
cbvab.1	|- F/ y ph
cbvab.2	|- F/ x ps
cbvab.3	|- ( x = y -> ( ph <-> ps ) )

Assertion

Ref	Expression
cbvab	|- { x | ph } = { y | ps }

Proof of Theorem cbvab

Dummy variable z is distinct from all other variables.

Step	Hyp	Ref	Expression
1		cbvab.2	. . . . 5 |- F/ x ps
2	1	nfsb 1975	. . . 4 |- F/ x [ z / y ] ps
3		cbvab.1	. . . . . 6 |- F/ y ph
4		cbvab.3	. . . . . . . 8 |- ( x = y -> ( ph <-> ps ) )
5	4	equcoms 1732	. . . . . . 7 |- ( y = x -> ( ph <-> ps ) )
6	5	bicomd 141	. . . . . 6 |- ( y = x -> ( ps <-> ph ) )
7	3, 6	sbie 1815	. . . . 5 |- ( [ x / y ] ps <-> ph )
8		sbequ 1864	. . . . 5 |- ( x = z -> ( [ x / y ] ps <-> [ z / y ] ps ) )
9	7, 8	bitr3id 194	. . . 4 |- ( x = z -> ( ph <-> [ z / y ] ps ) )
10	2, 9	sbie 1815	. . 3 |- ( [ z / x ] ph <-> [ z / y ] ps )
11		df-clab 2194	. . 3 |- ( z e. { x | ph } <-> [ z / x ] ph )
12		df-clab 2194	. . 3 |- ( z e. { y | ps } <-> [ z / y ] ps )
13	10, 11, 12	3bitr4i 212	. 2 |- ( z e. { x | ph } <-> z e. { y | ps } )
14	13	eqriv 2204	1 |- { x | ph } = { y | ps }

Syntax hints:   -> wi 4   <-> wb 105   = wceq 1373   F/wnf 1484   [wsb 1786   e. wcel 2178   {cab 2193

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 711  ax-5 1471  ax-7 1472  ax-gen 1473  ax-ie1 1517  ax-ie2 1518  ax-8 1528  ax-10 1529  ax-11 1530  ax-i12 1531  ax-bndl 1533  ax-4 1534  ax-17 1550  ax-i9 1554  ax-ial 1558  ax-i5r 1559  ax-ext 2189

This theorem depends on definitions:  df-bi 117  df-nf 1485  df-sb 1787  df-clab 2194  df-cleq 2200

This theorem is referenced by:  cbvabv  2332  cbvrab  2774  cbvsbc  3034  cbvrabcsf  3167  dfdmf  4890  dfrnf  4938  funfvdm2f  5667  abrexex2g  6228  abrexex2  6232