Theorem sbabel 2335

Description: Theorem to move a substitution in and out of a class abstraction. (Contributed by NM, 27-Sep-2003.) (Revised by Mario Carneiro, 7-Oct-2016.)

Hypothesis

Ref	Expression
sbabel.1	|- F/_ x A

Assertion

Ref	Expression
sbabel	|- ( [ y / x ] { z | ph } e. A <-> { z | [ y / x ] ph } e. A )

Distinct variable groups:   x, z   y, z

Allowed substitution hints:   ph( x, y, z)   A( x, y, z)

Proof of Theorem sbabel

Dummy variable v is distinct from all other variables.

Step	Hyp	Ref	Expression
1		sbex 1992	. . 3 |- ( [ y / x ] E. v ( v = { z | ph } /\ v e. A ) <-> E. v [ y / x ] ( v = { z | ph } /\ v e. A ) )
2		sban 1943	. . . . 5 |- ( [ y / x ] ( v = { z | ph } /\ v e. A ) <-> ( [ y / x ] v = { z | ph } /\ [ y / x ] v e. A ) )
3		nfv 1516	. . . . . . . . . 10 |- F/ x z e. v
4	3	sbf 1765	. . . . . . . . 9 |- ( [ y / x ] z e. v <-> z e. v )
5	4	sbrbis 1949	. . . . . . . 8 |- ( [ y / x ] ( z e. v <-> ph ) <-> ( z e. v <-> [ y / x ] ph ) )
6	5	sbalv 1993	. . . . . . 7 |- ( [ y / x ] A. z ( z e. v <-> ph ) <-> A. z ( z e. v <-> [ y / x ] ph ) )
7		abeq2 2275	. . . . . . . 8 |- ( v = { z | ph } <-> A. z ( z e. v <-> ph ) )
8	7	sbbii 1753	. . . . . . 7 |- ( [ y / x ] v = { z | ph } <-> [ y / x ] A. z ( z e. v <-> ph ) )
9		abeq2 2275	. . . . . . 7 |- ( v = { z | [ y / x ] ph } <-> A. z ( z e. v <-> [ y / x ] ph ) )
10	6, 8, 9	3bitr4i 211	. . . . . 6 |- ( [ y / x ] v = { z | ph } <-> v = { z | [ y / x ] ph } )
11		sbabel.1	. . . . . . . 8 |- F/_ x A
12	11	nfcri 2302	. . . . . . 7 |- F/ x v e. A
13	12	sbf 1765	. . . . . 6 |- ( [ y / x ] v e. A <-> v e. A )
14	10, 13	anbi12i 456	. . . . 5 |- ( ( [ y / x ] v = { z | ph } /\ [ y / x ] v e. A ) <-> ( v = { z | [ y / x ] ph } /\ v e. A ) )
15	2, 14	bitri 183	. . . 4 |- ( [ y / x ] ( v = { z | ph } /\ v e. A ) <-> ( v = { z | [ y / x ] ph } /\ v e. A ) )
16	15	exbii 1593	. . 3 |- ( E. v [ y / x ] ( v = { z | ph } /\ v e. A ) <-> E. v ( v = { z | [ y / x ] ph } /\ v e. A ) )
17	1, 16	bitri 183	. 2 |- ( [ y / x ] E. v ( v = { z | ph } /\ v e. A ) <-> E. v ( v = { z | [ y / x ] ph } /\ v e. A ) )
18		df-clel 2161	. . 3 |- ( { z | ph } e. A <-> E. v ( v = { z | ph } /\ v e. A ) )
19	18	sbbii 1753	. 2 |- ( [ y / x ] { z | ph } e. A <-> [ y / x ] E. v ( v = { z | ph } /\ v e. A ) )
20		df-clel 2161	. 2 |- ( { z | [ y / x ] ph } e. A <-> E. v ( v = { z | [ y / x ] ph } /\ v e. A ) )
21	17, 19, 20	3bitr4i 211	1 |- ( [ y / x ] { z | ph } e. A <-> { z | [ y / x ] ph } e. A )

Syntax hints:   /\ wa 103   <-> wb 104   A.wal 1341   = wceq 1343   E.wex 1480   [wsb 1750   e. wcel 2136   {cab 2151   F/_wnfc 2295

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-clab 2152  df-cleq 2158  df-clel 2161  df-nfc 2297

This theorem is referenced by: (None)