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Theorem ifpnot23 39979
 Description: Negation of conditional logical operator. (Contributed by RP, 18-Apr-2020.)
Assertion
Ref Expression
ifpnot23 (¬ if-(𝜑, 𝜓, 𝜒) ↔ if-(𝜑, ¬ 𝜓, ¬ 𝜒))

Proof of Theorem ifpnot23
StepHypRef Expression
1 ianor 978 . . . 4 (¬ (𝜑𝜓) ↔ (¬ 𝜑 ∨ ¬ 𝜓))
2 pm4.55 984 . . . 4 (¬ (¬ 𝜑𝜒) ↔ (𝜑 ∨ ¬ 𝜒))
31, 2anbi12i 628 . . 3 ((¬ (𝜑𝜓) ∧ ¬ (¬ 𝜑𝜒)) ↔ ((¬ 𝜑 ∨ ¬ 𝜓) ∧ (𝜑 ∨ ¬ 𝜒)))
4 ioran 980 . . 3 (¬ ((𝜑𝜓) ∨ (¬ 𝜑𝜒)) ↔ (¬ (𝜑𝜓) ∧ ¬ (¬ 𝜑𝜒)))
5 dfifp4 1061 . . 3 (if-(𝜑, ¬ 𝜓, ¬ 𝜒) ↔ ((¬ 𝜑 ∨ ¬ 𝜓) ∧ (𝜑 ∨ ¬ 𝜒)))
63, 4, 53bitr4i 305 . 2 (¬ ((𝜑𝜓) ∨ (¬ 𝜑𝜒)) ↔ if-(𝜑, ¬ 𝜓, ¬ 𝜒))
7 df-ifp 1058 . 2 (if-(𝜑, 𝜓, 𝜒) ↔ ((𝜑𝜓) ∨ (¬ 𝜑𝜒)))
86, 7xchnxbir 335 1 (¬ if-(𝜑, 𝜓, 𝜒) ↔ if-(𝜑, ¬ 𝜓, ¬ 𝜒))
 Colors of variables: wff setvar class Syntax hints:  ¬ wn 3   ↔ wb 208   ∧ wa 398   ∨ wo 843  if-wif 1057 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 209  df-an 399  df-or 844  df-ifp 1058 This theorem is referenced by:  ifpnotnotb  39980  ifpnorcor  39981  ifpnancor  39982  ifpnot23b  39983  ifpnot23c  39985  ifpnot23d  39986  ifpdfnan  39987  ifpdfxor  39988  ifpor123g  40009
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