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Metamath Proof Explorer
Description: Theorem *2.41 of WhiteheadRussell p. 106. (Contributed by NM, 3-Jan-2005)
|
|
Ref |
Expression |
|
Assertion |
pm2.41 |
⊢ ( ( 𝜓 ∨ ( 𝜑 ∨ 𝜓 ) ) → ( 𝜑 ∨ 𝜓 ) ) |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
olc |
⊢ ( 𝜓 → ( 𝜑 ∨ 𝜓 ) ) |
| 2 |
|
id |
⊢ ( ( 𝜑 ∨ 𝜓 ) → ( 𝜑 ∨ 𝜓 ) ) |
| 3 |
1 2
|
jaoi |
⊢ ( ( 𝜓 ∨ ( 𝜑 ∨ 𝜓 ) ) → ( 𝜑 ∨ 𝜓 ) ) |