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Theorem stoic2b 1319
Description: Stoic logic Thema 2 version b. See stoic2a 1318.

Version b is with the phrase "or both". We already have this rule as mpd3an3 1233, so here we prove the equivalence and discourage its use. (New usage is discouraged.) (Contributed by David A. Wheeler, 17-Feb-2019.)

Hypotheses
Ref Expression
stoic2b.1 ((𝜑𝜓) → 𝜒)
stoic2b.2 ((𝜑𝜓𝜒) → 𝜃)
Assertion
Ref Expression
stoic2b ((𝜑𝜓) → 𝜃)

Proof of Theorem stoic2b
StepHypRef Expression
1 stoic2b.1 . 2 ((𝜑𝜓) → 𝜒)
2 stoic2b.2 . 2 ((𝜑𝜓𝜒) → 𝜃)
31, 2mpd3an3 1233 1 ((𝜑𝜓) → 𝜃)
Colors of variables: wff set class
Syntax hints:  wi 4  wa 97  w3a 885
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101
This theorem depends on definitions:  df-bi 110  df-3an 887
This theorem is referenced by: (None)
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