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Theorem simpl-P2.9a 134
Description: '' Left Simplification.
Assertion
Ref Expression
simpl-P2.9a ((𝜑𝜓) → 𝜑)

Proof of Theorem simpl-P2.9a
StepHypRef Expression
1 df-and-D2.2 133 . . 3 ((𝜑𝜓) ↔ ¬ (𝜑 → ¬ 𝜓))
21bifwd-P2.5a.SH 112 . 2 ((𝜑𝜓) → ¬ (𝜑 → ¬ 𝜓))
3 simpl-L2.2a 95 . 2 (¬ (𝜑 → ¬ 𝜓) → 𝜑)
42, 3syl-P1.2 34 1 ((𝜑𝜓) → 𝜑)
Colors of variables: wff objvar term class
Syntax hints:  ¬ wff-neg 9  wff-imp 10  wff-and 132
This theorem was proved from axioms:  ax-L1 11  ax-L2 12  ax-L3 13  ax-MP 14
This theorem depends on definitions:  df-bi-D2.1 107  df-and-D2.2 133
This theorem is referenced by:  simpl-P2.9a.AC.SH  135  import-P2.10a  140  orelim-P2.11c  150
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