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Mirrors > Home > ILE Home > Th. List > bi2.04 | GIF version |
Description: Logical equivalence of commuted antecedents. Part of Theorem *4.87 of [WhiteheadRussell] p. 122. (Contributed by NM, 5-Aug-1993.) |
Ref | Expression |
---|---|
bi2.04 | ⊢ ((𝜑 → (𝜓 → 𝜒)) ↔ (𝜓 → (𝜑 → 𝜒))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pm2.04 82 | . 2 ⊢ ((𝜑 → (𝜓 → 𝜒)) → (𝜓 → (𝜑 → 𝜒))) | |
2 | pm2.04 82 | . 2 ⊢ ((𝜓 → (𝜑 → 𝜒)) → (𝜑 → (𝜓 → 𝜒))) | |
3 | 1, 2 | impbii 125 | 1 ⊢ ((𝜑 → (𝜓 → 𝜒)) ↔ (𝜓 → (𝜑 → 𝜒))) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ↔ wb 104 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia2 106 ax-ia3 107 |
This theorem depends on definitions: df-bi 116 |
This theorem is referenced by: imim21b 251 pm4.87 546 imimorbdc 881 sbcom2v 1958 mor 2039 r19.21t 2505 reu8 2875 ra5 2992 unissb 3761 reusv3 4376 zfregfr 4483 tfi 4491 fun11 5185 prime 9143 raluz2 9367 isprm3 11788 isprm4 11789 bj-inf2vnlem2 13158 |
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