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Metamath Proof Explorer
Description: Theorem *5.11 of WhiteheadRussell p. 123. (Contributed by NM, 3-Jan-2005)
|
|
Ref |
Expression |
|
Assertion |
pm5.11 |
⊢ ( ( 𝜑 → 𝜓 ) ∨ ( ¬ 𝜑 → 𝜓 ) ) |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
pm5.11g |
⊢ ( ( 𝜑 → 𝜓 ) ∨ ( ¬ 𝜑 → 𝜓 ) ) |