Proof of Theorem djuen
Step | Hyp | Ref
| Expression |
1 | | 0ex 5226 |
. . . . 5
⊢ ∅
∈ V |
2 | | relen 8696 |
. . . . . 6
⊢ Rel
≈ |
3 | 2 | brrelex1i 5634 |
. . . . 5
⊢ (𝐴 ≈ 𝐵 → 𝐴 ∈ V) |
4 | | xpsnen2g 8805 |
. . . . 5
⊢ ((∅
∈ V ∧ 𝐴 ∈ V)
→ ({∅} × 𝐴) ≈ 𝐴) |
5 | 1, 3, 4 | sylancr 586 |
. . . 4
⊢ (𝐴 ≈ 𝐵 → ({∅} × 𝐴) ≈ 𝐴) |
6 | 2 | brrelex2i 5635 |
. . . . . . 7
⊢ (𝐴 ≈ 𝐵 → 𝐵 ∈ V) |
7 | | xpsnen2g 8805 |
. . . . . . 7
⊢ ((∅
∈ V ∧ 𝐵 ∈ V)
→ ({∅} × 𝐵) ≈ 𝐵) |
8 | 1, 6, 7 | sylancr 586 |
. . . . . 6
⊢ (𝐴 ≈ 𝐵 → ({∅} × 𝐵) ≈ 𝐵) |
9 | 8 | ensymd 8746 |
. . . . 5
⊢ (𝐴 ≈ 𝐵 → 𝐵 ≈ ({∅} × 𝐵)) |
10 | | entr 8747 |
. . . . 5
⊢ ((𝐴 ≈ 𝐵 ∧ 𝐵 ≈ ({∅} × 𝐵)) → 𝐴 ≈ ({∅} × 𝐵)) |
11 | 9, 10 | mpdan 683 |
. . . 4
⊢ (𝐴 ≈ 𝐵 → 𝐴 ≈ ({∅} × 𝐵)) |
12 | | entr 8747 |
. . . 4
⊢
((({∅} × 𝐴) ≈ 𝐴 ∧ 𝐴 ≈ ({∅} × 𝐵)) → ({∅} ×
𝐴) ≈ ({∅}
× 𝐵)) |
13 | 5, 11, 12 | syl2anc 583 |
. . 3
⊢ (𝐴 ≈ 𝐵 → ({∅} × 𝐴) ≈ ({∅} × 𝐵)) |
14 | | 1on 8274 |
. . . . 5
⊢
1o ∈ On |
15 | 2 | brrelex1i 5634 |
. . . . 5
⊢ (𝐶 ≈ 𝐷 → 𝐶 ∈ V) |
16 | | xpsnen2g 8805 |
. . . . 5
⊢
((1o ∈ On ∧ 𝐶 ∈ V) → ({1o} ×
𝐶) ≈ 𝐶) |
17 | 14, 15, 16 | sylancr 586 |
. . . 4
⊢ (𝐶 ≈ 𝐷 → ({1o} × 𝐶) ≈ 𝐶) |
18 | 2 | brrelex2i 5635 |
. . . . . . 7
⊢ (𝐶 ≈ 𝐷 → 𝐷 ∈ V) |
19 | | xpsnen2g 8805 |
. . . . . . 7
⊢
((1o ∈ On ∧ 𝐷 ∈ V) → ({1o} ×
𝐷) ≈ 𝐷) |
20 | 14, 18, 19 | sylancr 586 |
. . . . . 6
⊢ (𝐶 ≈ 𝐷 → ({1o} × 𝐷) ≈ 𝐷) |
21 | 20 | ensymd 8746 |
. . . . 5
⊢ (𝐶 ≈ 𝐷 → 𝐷 ≈ ({1o} × 𝐷)) |
22 | | entr 8747 |
. . . . 5
⊢ ((𝐶 ≈ 𝐷 ∧ 𝐷 ≈ ({1o} × 𝐷)) → 𝐶 ≈ ({1o} × 𝐷)) |
23 | 21, 22 | mpdan 683 |
. . . 4
⊢ (𝐶 ≈ 𝐷 → 𝐶 ≈ ({1o} × 𝐷)) |
24 | | entr 8747 |
. . . 4
⊢
((({1o} × 𝐶) ≈ 𝐶 ∧ 𝐶 ≈ ({1o} × 𝐷)) → ({1o}
× 𝐶) ≈
({1o} × 𝐷)) |
25 | 17, 23, 24 | syl2anc 583 |
. . 3
⊢ (𝐶 ≈ 𝐷 → ({1o} × 𝐶) ≈ ({1o}
× 𝐷)) |
26 | | xp01disjl 8288 |
. . . 4
⊢
(({∅} × 𝐴) ∩ ({1o} × 𝐶)) = ∅ |
27 | | xp01disjl 8288 |
. . . 4
⊢
(({∅} × 𝐵) ∩ ({1o} × 𝐷)) = ∅ |
28 | | unen 8790 |
. . . 4
⊢
(((({∅} × 𝐴) ≈ ({∅} × 𝐵) ∧ ({1o} ×
𝐶) ≈ ({1o}
× 𝐷)) ∧
((({∅} × 𝐴)
∩ ({1o} × 𝐶)) = ∅ ∧ (({∅} × 𝐵) ∩ ({1o} ×
𝐷)) = ∅)) →
(({∅} × 𝐴)
∪ ({1o} × 𝐶)) ≈ (({∅} × 𝐵) ∪ ({1o} ×
𝐷))) |
29 | 26, 27, 28 | mpanr12 701 |
. . 3
⊢
((({∅} × 𝐴) ≈ ({∅} × 𝐵) ∧ ({1o} ×
𝐶) ≈ ({1o}
× 𝐷)) →
(({∅} × 𝐴)
∪ ({1o} × 𝐶)) ≈ (({∅} × 𝐵) ∪ ({1o} ×
𝐷))) |
30 | 13, 25, 29 | syl2an 595 |
. 2
⊢ ((𝐴 ≈ 𝐵 ∧ 𝐶 ≈ 𝐷) → (({∅} × 𝐴) ∪ ({1o} ×
𝐶)) ≈ (({∅}
× 𝐵) ∪
({1o} × 𝐷))) |
31 | | df-dju 9590 |
. 2
⊢ (𝐴 ⊔ 𝐶) = (({∅} × 𝐴) ∪ ({1o} × 𝐶)) |
32 | | df-dju 9590 |
. 2
⊢ (𝐵 ⊔ 𝐷) = (({∅} × 𝐵) ∪ ({1o} × 𝐷)) |
33 | 30, 31, 32 | 3brtr4g 5104 |
1
⊢ ((𝐴 ≈ 𝐵 ∧ 𝐶 ≈ 𝐷) → (𝐴 ⊔ 𝐶) ≈ (𝐵 ⊔ 𝐷)) |