Proof of Theorem prneimg
| Step | Hyp | Ref
| Expression |
| 1 | | preq12bg 3804 |
. . . . 5
⊢ (((𝐴 ∈ 𝑈 ∧ 𝐵 ∈ 𝑉) ∧ (𝐶 ∈ 𝑋 ∧ 𝐷 ∈ 𝑌)) → ({𝐴, 𝐵} = {𝐶, 𝐷} ↔ ((𝐴 = 𝐶 ∧ 𝐵 = 𝐷) ∨ (𝐴 = 𝐷 ∧ 𝐵 = 𝐶)))) |
| 2 | | orddi 821 |
. . . . . 6
⊢ (((𝐴 = 𝐶 ∧ 𝐵 = 𝐷) ∨ (𝐴 = 𝐷 ∧ 𝐵 = 𝐶)) ↔ (((𝐴 = 𝐶 ∨ 𝐴 = 𝐷) ∧ (𝐴 = 𝐶 ∨ 𝐵 = 𝐶)) ∧ ((𝐵 = 𝐷 ∨ 𝐴 = 𝐷) ∧ (𝐵 = 𝐷 ∨ 𝐵 = 𝐶)))) |
| 3 | | simpll 527 |
. . . . . . 7
⊢ ((((𝐴 = 𝐶 ∨ 𝐴 = 𝐷) ∧ (𝐴 = 𝐶 ∨ 𝐵 = 𝐶)) ∧ ((𝐵 = 𝐷 ∨ 𝐴 = 𝐷) ∧ (𝐵 = 𝐷 ∨ 𝐵 = 𝐶))) → (𝐴 = 𝐶 ∨ 𝐴 = 𝐷)) |
| 4 | | pm1.4 728 |
. . . . . . . 8
⊢ ((𝐵 = 𝐷 ∨ 𝐵 = 𝐶) → (𝐵 = 𝐶 ∨ 𝐵 = 𝐷)) |
| 5 | 4 | ad2antll 491 |
. . . . . . 7
⊢ ((((𝐴 = 𝐶 ∨ 𝐴 = 𝐷) ∧ (𝐴 = 𝐶 ∨ 𝐵 = 𝐶)) ∧ ((𝐵 = 𝐷 ∨ 𝐴 = 𝐷) ∧ (𝐵 = 𝐷 ∨ 𝐵 = 𝐶))) → (𝐵 = 𝐶 ∨ 𝐵 = 𝐷)) |
| 6 | 3, 5 | jca 306 |
. . . . . 6
⊢ ((((𝐴 = 𝐶 ∨ 𝐴 = 𝐷) ∧ (𝐴 = 𝐶 ∨ 𝐵 = 𝐶)) ∧ ((𝐵 = 𝐷 ∨ 𝐴 = 𝐷) ∧ (𝐵 = 𝐷 ∨ 𝐵 = 𝐶))) → ((𝐴 = 𝐶 ∨ 𝐴 = 𝐷) ∧ (𝐵 = 𝐶 ∨ 𝐵 = 𝐷))) |
| 7 | 2, 6 | sylbi 121 |
. . . . 5
⊢ (((𝐴 = 𝐶 ∧ 𝐵 = 𝐷) ∨ (𝐴 = 𝐷 ∧ 𝐵 = 𝐶)) → ((𝐴 = 𝐶 ∨ 𝐴 = 𝐷) ∧ (𝐵 = 𝐶 ∨ 𝐵 = 𝐷))) |
| 8 | 1, 7 | biimtrdi 163 |
. . . 4
⊢ (((𝐴 ∈ 𝑈 ∧ 𝐵 ∈ 𝑉) ∧ (𝐶 ∈ 𝑋 ∧ 𝐷 ∈ 𝑌)) → ({𝐴, 𝐵} = {𝐶, 𝐷} → ((𝐴 = 𝐶 ∨ 𝐴 = 𝐷) ∧ (𝐵 = 𝐶 ∨ 𝐵 = 𝐷)))) |
| 9 | | oranim 782 |
. . . . . 6
⊢ ((𝐴 = 𝐶 ∨ 𝐴 = 𝐷) → ¬ (¬ 𝐴 = 𝐶 ∧ ¬ 𝐴 = 𝐷)) |
| 10 | | df-ne 2368 |
. . . . . . 7
⊢ (𝐴 ≠ 𝐶 ↔ ¬ 𝐴 = 𝐶) |
| 11 | | df-ne 2368 |
. . . . . . 7
⊢ (𝐴 ≠ 𝐷 ↔ ¬ 𝐴 = 𝐷) |
| 12 | 10, 11 | anbi12i 460 |
. . . . . 6
⊢ ((𝐴 ≠ 𝐶 ∧ 𝐴 ≠ 𝐷) ↔ (¬ 𝐴 = 𝐶 ∧ ¬ 𝐴 = 𝐷)) |
| 13 | 9, 12 | sylnibr 678 |
. . . . 5
⊢ ((𝐴 = 𝐶 ∨ 𝐴 = 𝐷) → ¬ (𝐴 ≠ 𝐶 ∧ 𝐴 ≠ 𝐷)) |
| 14 | | oranim 782 |
. . . . . 6
⊢ ((𝐵 = 𝐶 ∨ 𝐵 = 𝐷) → ¬ (¬ 𝐵 = 𝐶 ∧ ¬ 𝐵 = 𝐷)) |
| 15 | | df-ne 2368 |
. . . . . . 7
⊢ (𝐵 ≠ 𝐶 ↔ ¬ 𝐵 = 𝐶) |
| 16 | | df-ne 2368 |
. . . . . . 7
⊢ (𝐵 ≠ 𝐷 ↔ ¬ 𝐵 = 𝐷) |
| 17 | 15, 16 | anbi12i 460 |
. . . . . 6
⊢ ((𝐵 ≠ 𝐶 ∧ 𝐵 ≠ 𝐷) ↔ (¬ 𝐵 = 𝐶 ∧ ¬ 𝐵 = 𝐷)) |
| 18 | 14, 17 | sylnibr 678 |
. . . . 5
⊢ ((𝐵 = 𝐶 ∨ 𝐵 = 𝐷) → ¬ (𝐵 ≠ 𝐶 ∧ 𝐵 ≠ 𝐷)) |
| 19 | 13, 18 | anim12i 338 |
. . . 4
⊢ (((𝐴 = 𝐶 ∨ 𝐴 = 𝐷) ∧ (𝐵 = 𝐶 ∨ 𝐵 = 𝐷)) → (¬ (𝐴 ≠ 𝐶 ∧ 𝐴 ≠ 𝐷) ∧ ¬ (𝐵 ≠ 𝐶 ∧ 𝐵 ≠ 𝐷))) |
| 20 | 8, 19 | syl6 33 |
. . 3
⊢ (((𝐴 ∈ 𝑈 ∧ 𝐵 ∈ 𝑉) ∧ (𝐶 ∈ 𝑋 ∧ 𝐷 ∈ 𝑌)) → ({𝐴, 𝐵} = {𝐶, 𝐷} → (¬ (𝐴 ≠ 𝐶 ∧ 𝐴 ≠ 𝐷) ∧ ¬ (𝐵 ≠ 𝐶 ∧ 𝐵 ≠ 𝐷)))) |
| 21 | | pm4.56 781 |
. . 3
⊢ ((¬
(𝐴 ≠ 𝐶 ∧ 𝐴 ≠ 𝐷) ∧ ¬ (𝐵 ≠ 𝐶 ∧ 𝐵 ≠ 𝐷)) ↔ ¬ ((𝐴 ≠ 𝐶 ∧ 𝐴 ≠ 𝐷) ∨ (𝐵 ≠ 𝐶 ∧ 𝐵 ≠ 𝐷))) |
| 22 | 20, 21 | imbitrdi 161 |
. 2
⊢ (((𝐴 ∈ 𝑈 ∧ 𝐵 ∈ 𝑉) ∧ (𝐶 ∈ 𝑋 ∧ 𝐷 ∈ 𝑌)) → ({𝐴, 𝐵} = {𝐶, 𝐷} → ¬ ((𝐴 ≠ 𝐶 ∧ 𝐴 ≠ 𝐷) ∨ (𝐵 ≠ 𝐶 ∧ 𝐵 ≠ 𝐷)))) |
| 23 | 22 | necon2ad 2424 |
1
⊢ (((𝐴 ∈ 𝑈 ∧ 𝐵 ∈ 𝑉) ∧ (𝐶 ∈ 𝑋 ∧ 𝐷 ∈ 𝑌)) → (((𝐴 ≠ 𝐶 ∧ 𝐴 ≠ 𝐷) ∨ (𝐵 ≠ 𝐶 ∧ 𝐵 ≠ 𝐷)) → {𝐴, 𝐵} ≠ {𝐶, 𝐷})) |