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Theorem csbsng 3498
Description: Distribute proper substitution through the singleton of a class. (Contributed by Alan Sare, 10-Nov-2012.)
Assertion
Ref Expression
csbsng  |-  ( A  e.  V  ->  [_ A  /  x ]_ { B }  =  { [_ A  /  x ]_ B }
)

Proof of Theorem csbsng
Dummy variable  y is distinct from all other variables.
StepHypRef Expression
1 csbabg 2987 . . 3  |-  ( A  e.  V  ->  [_ A  /  x ]_ { y  |  y  =  B }  =  { y  |  [. A  /  x ]. y  =  B } )
2 sbceq2g 2951 . . . 4  |-  ( A  e.  V  ->  ( [. A  /  x ]. y  =  B  <->  y  =  [_ A  /  x ]_ B ) )
32abbidv 2205 . . 3  |-  ( A  e.  V  ->  { y  |  [. A  /  x ]. y  =  B }  =  { y  |  y  =  [_ A  /  x ]_ B } )
41, 3eqtrd 2120 . 2  |-  ( A  e.  V  ->  [_ A  /  x ]_ { y  |  y  =  B }  =  { y  |  y  =  [_ A  /  x ]_ B } )
5 df-sn 3447 . . 3  |-  { B }  =  { y  |  y  =  B }
65csbeq2i 2955 . 2  |-  [_ A  /  x ]_ { B }  =  [_ A  /  x ]_ { y  |  y  =  B }
7 df-sn 3447 . 2  |-  { [_ A  /  x ]_ B }  =  { y  |  y  =  [_ A  /  x ]_ B }
84, 6, 73eqtr4g 2145 1  |-  ( A  e.  V  ->  [_ A  /  x ]_ { B }  =  { [_ A  /  x ]_ B }
)
Colors of variables: wff set class
Syntax hints:    -> wi 4    = wceq 1289    e. wcel 1438   {cab 2074   [.wsbc 2838   [_csb 2931   {csn 3441
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-io 665  ax-5 1381  ax-7 1382  ax-gen 1383  ax-ie1 1427  ax-ie2 1428  ax-8 1440  ax-10 1441  ax-11 1442  ax-i12 1443  ax-bndl 1444  ax-4 1445  ax-17 1464  ax-i9 1468  ax-ial 1472  ax-i5r 1473  ax-ext 2070
This theorem depends on definitions:  df-bi 115  df-tru 1292  df-nf 1395  df-sb 1693  df-clab 2075  df-cleq 2081  df-clel 2084  df-nfc 2217  df-v 2621  df-sbc 2839  df-csb 2932  df-sn 3447
This theorem is referenced by: (None)
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