Proof of Theorem 3ornot23VD
Step | Hyp | Ref
| Expression |
1 | | idn1 42194 |
. . . . . 6
⊢ ( (¬ 𝜑 ∧ ¬ 𝜓) ▶ (¬
𝜑 ∧ ¬ 𝜓) ) |
2 | | simpl 483 |
. . . . . 6
⊢ ((¬
𝜑 ∧ ¬ 𝜓) → ¬ 𝜑) |
3 | 1, 2 | e1a 42247 |
. . . . 5
⊢ ( (¬ 𝜑 ∧ ¬ 𝜓) ▶ ¬
𝜑 ) |
4 | | simpr 485 |
. . . . . 6
⊢ ((¬
𝜑 ∧ ¬ 𝜓) → ¬ 𝜓) |
5 | 1, 4 | e1a 42247 |
. . . . 5
⊢ ( (¬ 𝜑 ∧ ¬ 𝜓) ▶ ¬
𝜓 ) |
6 | | ioran 981 |
. . . . . 6
⊢ (¬
(𝜑 ∨ 𝜓) ↔ (¬ 𝜑 ∧ ¬ 𝜓)) |
7 | 6 | simplbi2 501 |
. . . . 5
⊢ (¬
𝜑 → (¬ 𝜓 → ¬ (𝜑 ∨ 𝜓))) |
8 | 3, 5, 7 | e11 42308 |
. . . 4
⊢ ( (¬ 𝜑 ∧ ¬ 𝜓) ▶ ¬
(𝜑 ∨ 𝜓) ) |
9 | | idn2 42233 |
. . . . 5
⊢ ( (¬ 𝜑 ∧ ¬ 𝜓) , (𝜒 ∨ 𝜑 ∨ 𝜓) ▶ (𝜒 ∨ 𝜑 ∨ 𝜓) ) |
10 | | 3orass 1089 |
. . . . . 6
⊢ ((𝜒 ∨ 𝜑 ∨ 𝜓) ↔ (𝜒 ∨ (𝜑 ∨ 𝜓))) |
11 | 10 | biimpi 215 |
. . . . 5
⊢ ((𝜒 ∨ 𝜑 ∨ 𝜓) → (𝜒 ∨ (𝜑 ∨ 𝜓))) |
12 | 9, 11 | e2 42251 |
. . . 4
⊢ ( (¬ 𝜑 ∧ ¬ 𝜓) , (𝜒 ∨ 𝜑 ∨ 𝜓) ▶ (𝜒 ∨ (𝜑 ∨ 𝜓)) ) |
13 | | orel2 888 |
. . . 4
⊢ (¬
(𝜑 ∨ 𝜓) → ((𝜒 ∨ (𝜑 ∨ 𝜓)) → 𝜒)) |
14 | 8, 12, 13 | e12 42344 |
. . 3
⊢ ( (¬ 𝜑 ∧ ¬ 𝜓) , (𝜒 ∨ 𝜑 ∨ 𝜓) ▶ 𝜒 ) |
15 | 14 | in2 42225 |
. 2
⊢ ( (¬ 𝜑 ∧ ¬ 𝜓) ▶ ((𝜒 ∨ 𝜑 ∨ 𝜓) → 𝜒) ) |
16 | 15 | in1 42191 |
1
⊢ ((¬
𝜑 ∧ ¬ 𝜓) → ((𝜒 ∨ 𝜑 ∨ 𝜓) → 𝜒)) |