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Mirrors > Home > MPE Home > Th. List > ancom | Structured version Visualization version GIF version |
Description: Commutative law for conjunction. Theorem *4.3 of [WhiteheadRussell] p. 118. (Contributed by NM, 25-Jun-1998.) (Proof shortened by Wolf Lammen, 4-Nov-2012.) |
Ref | Expression |
---|---|
ancom | ⊢ ((𝜑 ∧ 𝜓) ↔ (𝜓 ∧ 𝜑)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pm3.22 459 | . 2 ⊢ ((𝜑 ∧ 𝜓) → (𝜓 ∧ 𝜑)) | |
2 | pm3.22 459 | . 2 ⊢ ((𝜓 ∧ 𝜑) → (𝜑 ∧ 𝜓)) | |
3 | 1, 2 | impbii 208 | 1 ⊢ ((𝜑 ∧ 𝜓) ↔ (𝜓 ∧ 𝜑)) |
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