Theorem cbvab 2320

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 1965	. . . 4 |- F/ x [ z / y ] ps
3		cbvab.1	. . . . . 6 |- F/ y ph
4		cbvab.3	. . . . . . . 8 |- ( x = y -> ( ph <-> ps ) )
5	4	equcoms 1722	. . . . . . 7 |- ( y = x -> ( ph <-> ps ) )
6	5	bicomd 141	. . . . . 6 |- ( y = x -> ( ps <-> ph ) )
7	3, 6	sbie 1805	. . . . 5 |- ( [ x / y ] ps <-> ph )
8		sbequ 1854	. . . . 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 1805	. . 3 |- ( [ z / x ] ph <-> [ z / y ] ps )
11		df-clab 2183	. . 3 |- ( z e. { x | ph } <-> [ z / x ] ph )
12		df-clab 2183	. . 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 2193	1 |- { x | ph } = { y | ps }

Syntax hints:   -> wi 4   <-> wb 105   = wceq 1364   F/wnf 1474   [wsb 1776   e. wcel 2167   {cab 2182

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 710  ax-5 1461  ax-7 1462  ax-gen 1463  ax-ie1 1507  ax-ie2 1508  ax-8 1518  ax-10 1519  ax-11 1520  ax-i12 1521  ax-bndl 1523  ax-4 1524  ax-17 1540  ax-i9 1544  ax-ial 1548  ax-i5r 1549  ax-ext 2178

This theorem depends on definitions:  df-bi 117  df-nf 1475  df-sb 1777  df-clab 2183  df-cleq 2189

This theorem is referenced by:  cbvabv  2321  cbvrab  2761  cbvsbc  3018  cbvrabcsf  3150  dfdmf  4859  dfrnf  4907  funfvdm2f  5626  abrexex2g  6177  abrexex2  6181