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Theorem necon2i 2563
Description: Contrapositive inference for inequality. (Contributed by NM, 18-Mar-2007.)
Hypothesis
Ref Expression
necon2i.1 (A = BCD)
Assertion
Ref Expression
necon2i (C = DAB)

Proof of Theorem necon2i
StepHypRef Expression
1 necon2i.1 . . 3 (A = BCD)
21neneqd 2532 . 2 (A = B → ¬ C = D)
32necon2ai 2561 1 (C = DAB)
Colors of variables: wff setvar class
Syntax hints:  wi 4   = wceq 1642  wne 2516
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 177  df-ne 2518
This theorem is referenced by:  map0  6025
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