Theorem sbcsng 3725

Description: Substitution expressed in terms of quantification over a singleton. (Contributed by NM, 14-Dec-2005.) (Revised by Mario Carneiro, 23-Apr-2015.)

Assertion

Ref	Expression
sbcsng	|- ( A e. V -> ( [. A / x ]. ph <-> A. x e. { A } ph ) )

Distinct variable group:   x, A

Allowed substitution hints:   ph( x)   V( x)

Proof of Theorem sbcsng

Step	Hyp	Ref	Expression
1		ralsns 3704	. 2 |- ( A e. V -> ( A. x e. { A } ph <-> [. A / x ]. ph ) )
2	1	bicomd 141	1 |- ( A e. V -> ( [. A / x ]. ph <-> A. x e. { A } ph ) )

Syntax hints:   -> wi 4   <-> wb 105   e. wcel 2200   A.wral 2508   [.wsbc 3028   {csn 3666

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-ral 2513  df-v 2801  df-sbc 3029  df-sn 3672

This theorem is referenced by:  zsupcllemstep  10444