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Theorem bj-hbaeb2 32805
Description: Biconditional version of a form of hbae 2315 with commuted quantifiers, not requiring ax-11 2034. (Contributed by BJ, 12-Dec-2019.) (Proof modification is discouraged.)
Assertion
Ref Expression
bj-hbaeb2  |-  ( A. x  x  =  y  <->  A. x A. z  x  =  y )

Proof of Theorem bj-hbaeb2
StepHypRef Expression
1 sp 2053 . . . . 5  |-  ( A. x  x  =  y  ->  x  =  y )
2 axc9 2302 . . . . 5  |-  ( -. 
A. z  z  =  x  ->  ( -.  A. z  z  =  y  ->  ( x  =  y  ->  A. z  x  =  y )
) )
31, 2syl7 74 . . . 4  |-  ( -. 
A. z  z  =  x  ->  ( -.  A. z  z  =  y  ->  ( A. x  x  =  y  ->  A. z  x  =  y ) ) )
4 axc11r 2187 . . . 4  |-  ( A. z  z  =  x  ->  ( A. x  x  =  y  ->  A. z  x  =  y )
)
5 axc11 2314 . . . . . 6  |-  ( A. x  x  =  y  ->  ( A. x  x  =  y  ->  A. y  x  =  y )
)
65pm2.43i 52 . . . . 5  |-  ( A. x  x  =  y  ->  A. y  x  =  y )
7 axc11r 2187 . . . . 5  |-  ( A. z  z  =  y  ->  ( A. y  x  =  y  ->  A. z  x  =  y )
)
86, 7syl5 34 . . . 4  |-  ( A. z  z  =  y  ->  ( A. x  x  =  y  ->  A. z  x  =  y )
)
93, 4, 8pm2.61ii 177 . . 3  |-  ( A. x  x  =  y  ->  A. z  x  =  y )
109axc4i 2131 . 2  |-  ( A. x  x  =  y  ->  A. x A. z  x  =  y )
11 sp 2053 . . 3  |-  ( A. z  x  =  y  ->  x  =  y )
1211alimi 1739 . 2  |-  ( A. x A. z  x  =  y  ->  A. x  x  =  y )
1310, 12impbii 199 1  |-  ( A. x  x  =  y  <->  A. x A. z  x  =  y )
Colors of variables: wff setvar class
Syntax hints:   -. wn 3    -> wi 4    <-> wb 196   A.wal 1481
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-10 2019  ax-12 2047  ax-13 2246
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-tru 1486  df-ex 1705  df-nf 1710
This theorem is referenced by:  bj-hbaeb  32806  bj-dvv  32808
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