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Metamath Proof Explorer
Description: Theorem *3.22 of WhiteheadRussell p. 111. (Contributed by NM, 3-Jan-2005) (Proof shortened by Wolf Lammen, 13-Nov-2012)
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|
Ref |
Expression |
|
Assertion |
pm3.22 |
⊢ ( ( 𝜑 ∧ 𝜓 ) → ( 𝜓 ∧ 𝜑 ) ) |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
id |
⊢ ( ( 𝜓 ∧ 𝜑 ) → ( 𝜓 ∧ 𝜑 ) ) |
| 2 |
1
|
ancoms |
⊢ ( ( 𝜑 ∧ 𝜓 ) → ( 𝜓 ∧ 𝜑 ) ) |