Theorem sbcsng 3784

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 3764	. 2 |- (A e. V -> (A.x e. {A}ph <-> [.A / x ].ph))
2	1	bicomd 192	1 |- (A e. V -> ( [.A / x ].ph <-> A.x e. {A}ph))

Syntax hints:   -> wi 4   <-> wb 176   e. wcel 1710  A.wral 2615   [.wsbc 3047  {csn 3738

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2479  df-ral 2620  df-v 2862  df-sbc 3048  df-sn 3742

This theorem is referenced by: (None)