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Theorem necon4i 2701
Description: Contrapositive inference for inequality. (Contributed by NM, 17-Mar-2007.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 24-Nov-2019.)
Hypothesis
Ref Expression
necon4i.1
Assertion
Ref Expression
necon4i

Proof of Theorem necon4i
StepHypRef Expression
1 necon4i.1 . . 3
21neneqd 2659 . 2
32necon4ai 2695 1
Colors of variables: wff setvar class
Syntax hints:  ->wi 4  =wceq 1395  =/=wne 2652
This theorem is referenced by:  unixp0  5546  scott0  8325  nn0opthi  12350
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 185  df-ne 2654
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