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Theorem pm14.122b 27726
Description: Theorem *14.122 in [WhiteheadRussell] p. 185. (Contributed by Andrew Salmon, 9-Jun-2011.)
Assertion
Ref Expression
pm14.122b  |-  ( A  e.  V  ->  (
( A. x (
ph  ->  x  =  A )  /\  [. A  /  x ]. ph )  <->  ( A. x ( ph  ->  x  =  A )  /\  E. x ph ) ) )
Distinct variable group:    x, A
Allowed substitution hints:    ph( x)    V( x)

Proof of Theorem pm14.122b
Dummy variable  y is distinct from all other variables.
StepHypRef Expression
1 eqeq2 2305 . . . . . 6  |-  ( y  =  A  ->  (
x  =  y  <->  x  =  A ) )
21imbi2d 307 . . . . 5  |-  ( y  =  A  ->  (
( ph  ->  x  =  y )  <->  ( ph  ->  x  =  A ) ) )
32albidv 1615 . . . 4  |-  ( y  =  A  ->  ( A. x ( ph  ->  x  =  y )  <->  A. x
( ph  ->  x  =  A ) ) )
4 dfsbcq 3006 . . . . 5  |-  ( y  =  A  ->  ( [. y  /  x ]. ph  <->  [. A  /  x ]. ph ) )
54bibi1d 310 . . . 4  |-  ( y  =  A  ->  (
( [. y  /  x ]. ph  <->  E. x ph )  <->  (
[. A  /  x ]. ph  <->  E. x ph )
) )
63, 5imbi12d 311 . . 3  |-  ( y  =  A  ->  (
( A. x (
ph  ->  x  =  y )  ->  ( [. y  /  x ]. ph  <->  E. x ph ) )  <->  ( A. x ( ph  ->  x  =  A )  -> 
( [. A  /  x ]. ph  <->  E. x ph )
) ) )
7 sbc5 3028 . . . 4  |-  ( [. y  /  x ]. ph  <->  E. x
( x  =  y  /\  ph ) )
8 nfa1 1768 . . . . 5  |-  F/ x A. x ( ph  ->  x  =  y )
9 simpr 447 . . . . . 6  |-  ( ( x  =  y  /\  ph )  ->  ph )
10 ancr 532 . . . . . . 7  |-  ( (
ph  ->  x  =  y )  ->  ( ph  ->  ( x  =  y  /\  ph ) ) )
1110sps 1751 . . . . . 6  |-  ( A. x ( ph  ->  x  =  y )  -> 
( ph  ->  ( x  =  y  /\  ph ) ) )
129, 11impbid2 195 . . . . 5  |-  ( A. x ( ph  ->  x  =  y )  -> 
( ( x  =  y  /\  ph )  <->  ph ) )
138, 12exbid 1765 . . . 4  |-  ( A. x ( ph  ->  x  =  y )  -> 
( E. x ( x  =  y  /\  ph )  <->  E. x ph )
)
147, 13syl5bb 248 . . 3  |-  ( A. x ( ph  ->  x  =  y )  -> 
( [. y  /  x ]. ph  <->  E. x ph )
)
156, 14vtoclg 2856 . 2  |-  ( A  e.  V  ->  ( A. x ( ph  ->  x  =  A )  -> 
( [. A  /  x ]. ph  <->  E. x ph )
) )
1615pm5.32d 620 1  |-  ( A  e.  V  ->  (
( A. x (
ph  ->  x  =  A )  /\  [. A  /  x ]. ph )  <->  ( A. x ( ph  ->  x  =  A )  /\  E. x ph ) ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    <-> wb 176    /\ wa 358   A.wal 1530   E.wex 1531    = wceq 1632    e. wcel 1696   [.wsbc 3004
This theorem is referenced by:  pm14.122c  27727
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1536  ax-5 1547  ax-17 1606  ax-9 1644  ax-8 1661  ax-6 1715  ax-7 1720  ax-11 1727  ax-12 1878  ax-ext 2277
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-tru 1310  df-ex 1532  df-nf 1535  df-sb 1639  df-clab 2283  df-cleq 2289  df-clel 2292  df-nfc 2421  df-v 2803  df-sbc 3005
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