Theorem sbcalg 3081

Description: Move universal quantifier in and out of class substitution. (Contributed by NM, 16-Jan-2004.)

Assertion

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

Distinct variable groups:   x, A   x, y

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

Proof of Theorem sbcalg

Dummy variable z is distinct from all other variables.

Step	Hyp	Ref	Expression
1		dfsbcq2 3031	. 2 |- ( z = A -> ( [ z / y ] A. x ph <-> [. A / y ]. A. x ph ) )
2		dfsbcq2 3031	. . 3 |- ( z = A -> ( [ z / y ] ph <-> [. A / y ]. ph ) )
3	2	albidv 1870	. 2 |- ( z = A -> ( A. x [ z / y ] ph <-> A. x [. A / y ]. ph ) )
4		sbal 2051	. 2 |- ( [ z / y ] A. x ph <-> A. x [ z / y ] ph )
5	1, 3, 4	vtoclbg 2862	1 |- ( A e. V -> ( [. A / y ]. A. x ph <-> A. x [. A / y ]. ph ) )

Syntax hints:   -> wi 4   <-> wb 105   A.wal 1393   = wceq 1395   [wsb 1808   e. wcel 2200   [.wsbc 3028

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 714  ax-5 1493  ax-7 1494  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-8 1550  ax-10 1551  ax-11 1552  ax-i12 1553  ax-bndl 1555  ax-4 1556  ax-17 1572  ax-i9 1576  ax-ial 1580  ax-i5r 1581  ax-ext 2211

This theorem depends on definitions:  df-bi 117  df-tru 1398  df-nf 1507  df-sb 1809  df-clab 2216  df-cleq 2222  df-clel 2225  df-nfc 2361  df-v 2801  df-sbc 3029

This theorem is referenced by:  sbcabel  3111  sbcssg  3600