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Theorem wl-mo2t 28536
Description: Closed form of mo2 2272. (Contributed by Wolf Lammen, 18-Aug-2019.)
Assertion
Ref Expression
wl-mo2t  |-  ( A. x F/ y ph  ->  ( E* x ph  <->  E. y A. x ( ph  ->  x  =  y ) ) )
Distinct variable group:    x, y
Allowed substitution hints:    ph( x, y)

Proof of Theorem wl-mo2t
Dummy variable  u is distinct from all other variables.
StepHypRef Expression
1 mo2v 2267 . 2  |-  ( E* x ph  <->  E. u A. x ( ph  ->  x  =  u ) )
2 nfnf1 1835 . . . 4  |-  F/ y F/ y ph
32nfal 1882 . . 3  |-  F/ y A. x F/ y
ph
4 nfa1 1833 . . . 4  |-  F/ x A. x F/ y ph
5 sp 1796 . . . . 5  |-  ( A. x F/ y ph  ->  F/ y ph )
6 nfvd 1675 . . . . 5  |-  ( A. x F/ y ph  ->  F/ y  x  =  u )
75, 6nfimd 1852 . . . 4  |-  ( A. x F/ y ph  ->  F/ y ( ph  ->  x  =  u ) )
84, 7nfald 1886 . . 3  |-  ( A. x F/ y ph  ->  F/ y A. x (
ph  ->  x  =  u ) )
9 equequ2 1739 . . . . . 6  |-  ( u  =  y  ->  (
x  =  u  <->  x  =  y ) )
109imbi2d 316 . . . . 5  |-  ( u  =  y  ->  (
( ph  ->  x  =  u )  <->  ( ph  ->  x  =  y ) ) )
1110albidv 1680 . . . 4  |-  ( u  =  y  ->  ( A. x ( ph  ->  x  =  u )  <->  A. x
( ph  ->  x  =  y ) ) )
1211a1i 11 . . 3  |-  ( A. x F/ y ph  ->  ( u  =  y  -> 
( A. x (
ph  ->  x  =  u )  <->  A. x ( ph  ->  x  =  y ) ) ) )
133, 8, 12cbvexd 1983 . 2  |-  ( A. x F/ y ph  ->  ( E. u A. x
( ph  ->  x  =  u )  <->  E. y A. x ( ph  ->  x  =  y ) ) )
141, 13syl5bb 257 1  |-  ( A. x F/ y ph  ->  ( E* x ph  <->  E. y A. x ( ph  ->  x  =  y ) ) )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4    <-> wb 184   A.wal 1368   E.wex 1587   F/wnf 1590   E*wmo 2261
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1592  ax-4 1603  ax-5 1671  ax-6 1710  ax-7 1730  ax-10 1777  ax-11 1782  ax-12 1794  ax-13 1952
This theorem depends on definitions:  df-bi 185  df-an 371  df-ex 1588  df-nf 1591  df-eu 2264  df-mo 2265
This theorem is referenced by:  wl-mo3t  28537
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