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Theorem feq3d 5269
Description: Equality deduction for functions. (Contributed by AV, 1-Jan-2020.)
Hypothesis
Ref Expression
feq2d.1  |-  ( ph  ->  A  =  B )
Assertion
Ref Expression
feq3d  |-  ( ph  ->  ( F : X --> A 
<->  F : X --> B ) )

Proof of Theorem feq3d
StepHypRef Expression
1 feq2d.1 . 2  |-  ( ph  ->  A  =  B )
2 feq3 5265 . 2  |-  ( A  =  B  ->  ( F : X --> A  <->  F : X
--> B ) )
31, 2syl 14 1  |-  ( ph  ->  ( F : X --> A 
<->  F : X --> B ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    <-> wb 104    = wceq 1332   -->wf 5127
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-5 1424  ax-7 1425  ax-gen 1426  ax-ie1 1470  ax-ie2 1471  ax-8 1483  ax-11 1485  ax-4 1488  ax-17 1507  ax-i9 1511  ax-ial 1515  ax-i5r 1516  ax-ext 2122
This theorem depends on definitions:  df-bi 116  df-nf 1438  df-sb 1737  df-clab 2127  df-cleq 2133  df-clel 2136  df-in 3082  df-ss 3089  df-f 5135
This theorem is referenced by:  uptx  12482  txcn  12483
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