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Metamath Proof Explorer
Description: Theorem *2.38 of WhiteheadRussell p. 105. (Contributed by NM, 6-Mar-2008)
|
|
Ref |
Expression |
|
Assertion |
pm2.38 |
⊢ ( ( 𝜓 → 𝜒 ) → ( ( 𝜓 ∨ 𝜑 ) → ( 𝜒 ∨ 𝜑 ) ) ) |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
id |
⊢ ( ( 𝜓 → 𝜒 ) → ( 𝜓 → 𝜒 ) ) |
| 2 |
1
|
orim1d |
⊢ ( ( 𝜓 → 𝜒 ) → ( ( 𝜓 ∨ 𝜑 ) → ( 𝜒 ∨ 𝜑 ) ) ) |