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Theorem ccase 882
Description: Inference for combining cases. (Contributed by NM, 29-Jul-1999.) (Proof shortened by Wolf Lammen, 6-Jan-2013.)
Hypotheses
Ref Expression
ccase.1 ((𝜑𝜓) → 𝜏)
ccase.2 ((𝜒𝜓) → 𝜏)
ccase.3 ((𝜑𝜃) → 𝜏)
ccase.4 ((𝜒𝜃) → 𝜏)
Assertion
Ref Expression
ccase (((𝜑𝜒) ∧ (𝜓𝜃)) → 𝜏)

Proof of Theorem ccase
StepHypRef Expression
1 ccase.1 . . 3 ((𝜑𝜓) → 𝜏)
2 ccase.2 . . 3 ((𝜒𝜓) → 𝜏)
31, 2jaoian 719 . 2 (((𝜑𝜒) ∧ 𝜓) → 𝜏)
4 ccase.3 . . 3 ((𝜑𝜃) → 𝜏)
5 ccase.4 . . 3 ((𝜒𝜃) → 𝜏)
64, 5jaoian 719 . 2 (((𝜑𝜒) ∧ 𝜃) → 𝜏)
73, 6jaodan 721 1 (((𝜑𝜒) ∧ (𝜓𝜃)) → 𝜏)
Colors of variables: wff set class
Syntax hints:  wi 4  wa 101  wo 639
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 103  ax-ia2 104  ax-ia3 105  ax-io 640
This theorem depends on definitions:  df-bi 114
This theorem is referenced by:  ccased  883  ccase2  884  undif3ss  3226
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