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Theorem necon1aiOLD 2637
Description: Obsolete proof of necon1ai 2636 as of 22-Nov-2019. (Contributed by NM, 12-Feb-2007.) (Proof modification is discouraged.) (New usage is discouraged.)
Hypothesis
Ref Expression
necon1ai.1  |-  ( -. 
ph  ->  A  =  B )
Assertion
Ref Expression
necon1aiOLD  |-  ( A  =/=  B  ->  ph )

Proof of Theorem necon1aiOLD
StepHypRef Expression
1 df-ne 2602 . 2  |-  ( A  =/=  B  <->  -.  A  =  B )
2 necon1ai.1 . . 3  |-  ( -. 
ph  ->  A  =  B )
32con1i 131 . 2  |-  ( -.  A  =  B  ->  ph )
41, 3sylbi 197 1  |-  ( A  =/=  B  ->  ph )
Colors of variables: wff setvar class
Syntax hints:   -. wn 3    -> wi 4    = wceq 1407    =/= wne 2600
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8
This theorem depends on definitions:  df-bi 187  df-ne 2602
This theorem is referenced by: (None)
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