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Theorem xchbinxr 672
Description: Replacement of a subexpression by an equivalent one. (Contributed by Wolf Lammen, 27-Sep-2014.)
Hypotheses
Ref Expression
xchbinxr.1 (𝜑 ↔ ¬ 𝜓)
xchbinxr.2 (𝜒𝜓)
Assertion
Ref Expression
xchbinxr (𝜑 ↔ ¬ 𝜒)

Proof of Theorem xchbinxr
StepHypRef Expression
1 xchbinxr.1 . 2 (𝜑 ↔ ¬ 𝜓)
2 xchbinxr.2 . . 3 (𝜒𝜓)
32bicomi 131 . 2 (𝜓𝜒)
41, 3xchbinx 671 1 (𝜑 ↔ ¬ 𝜒)
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wb 104
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-in1 603  ax-in2 604
This theorem depends on definitions:  df-bi 116
This theorem is referenced by:  xordc1  1371  sbnv  1860  ralnex  2424  difab  3340  disjsn  3580  iindif2m  3875  reldm0  4752
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