Step | Hyp | Ref
| Expression |
1 | | sdom0 8778 |
. . . . 5
⊢ ¬
𝐴 ≺
∅ |
2 | | breq2 5057 |
. . . . 5
⊢ (𝐵 = ∅ → (𝐴 ≺ 𝐵 ↔ 𝐴 ≺ ∅)) |
3 | 1, 2 | mtbiri 330 |
. . . 4
⊢ (𝐵 = ∅ → ¬ 𝐴 ≺ 𝐵) |
4 | 3 | con2i 141 |
. . 3
⊢ (𝐴 ≺ 𝐵 → ¬ 𝐵 = ∅) |
5 | | neq0 4260 |
. . 3
⊢ (¬
𝐵 = ∅ ↔
∃𝑧 𝑧 ∈ 𝐵) |
6 | 4, 5 | sylib 221 |
. 2
⊢ (𝐴 ≺ 𝐵 → ∃𝑧 𝑧 ∈ 𝐵) |
7 | | domdifsn 8728 |
. . . . 5
⊢ (𝐴 ≺ 𝐵 → 𝐴 ≼ (𝐵 ∖ {𝑧})) |
8 | 7 | adantr 484 |
. . . 4
⊢ ((𝐴 ≺ 𝐵 ∧ 𝑧 ∈ 𝐵) → 𝐴 ≼ (𝐵 ∖ {𝑧})) |
9 | | en2sn 8718 |
. . . . . . 7
⊢ ((𝐶 ∈ V ∧ 𝑧 ∈ V) → {𝐶} ≈ {𝑧}) |
10 | 9 | elvd 3415 |
. . . . . 6
⊢ (𝐶 ∈ V → {𝐶} ≈ {𝑧}) |
11 | | endom 8655 |
. . . . . 6
⊢ ({𝐶} ≈ {𝑧} → {𝐶} ≼ {𝑧}) |
12 | 10, 11 | syl 17 |
. . . . 5
⊢ (𝐶 ∈ V → {𝐶} ≼ {𝑧}) |
13 | | snprc 4633 |
. . . . . . 7
⊢ (¬
𝐶 ∈ V ↔ {𝐶} = ∅) |
14 | 13 | biimpi 219 |
. . . . . 6
⊢ (¬
𝐶 ∈ V → {𝐶} = ∅) |
15 | | snex 5324 |
. . . . . . 7
⊢ {𝑧} ∈ V |
16 | 15 | 0dom 8776 |
. . . . . 6
⊢ ∅
≼ {𝑧} |
17 | 14, 16 | eqbrtrdi 5092 |
. . . . 5
⊢ (¬
𝐶 ∈ V → {𝐶} ≼ {𝑧}) |
18 | 12, 17 | pm2.61i 185 |
. . . 4
⊢ {𝐶} ≼ {𝑧} |
19 | | disjdifr 4387 |
. . . . 5
⊢ ((𝐵 ∖ {𝑧}) ∩ {𝑧}) = ∅ |
20 | | undom 8733 |
. . . . 5
⊢ (((𝐴 ≼ (𝐵 ∖ {𝑧}) ∧ {𝐶} ≼ {𝑧}) ∧ ((𝐵 ∖ {𝑧}) ∩ {𝑧}) = ∅) → (𝐴 ∪ {𝐶}) ≼ ((𝐵 ∖ {𝑧}) ∪ {𝑧})) |
21 | 19, 20 | mpan2 691 |
. . . 4
⊢ ((𝐴 ≼ (𝐵 ∖ {𝑧}) ∧ {𝐶} ≼ {𝑧}) → (𝐴 ∪ {𝐶}) ≼ ((𝐵 ∖ {𝑧}) ∪ {𝑧})) |
22 | 8, 18, 21 | sylancl 589 |
. . 3
⊢ ((𝐴 ≺ 𝐵 ∧ 𝑧 ∈ 𝐵) → (𝐴 ∪ {𝐶}) ≼ ((𝐵 ∖ {𝑧}) ∪ {𝑧})) |
23 | | uncom 4067 |
. . . 4
⊢ ((𝐵 ∖ {𝑧}) ∪ {𝑧}) = ({𝑧} ∪ (𝐵 ∖ {𝑧})) |
24 | | simpr 488 |
. . . . . 6
⊢ ((𝐴 ≺ 𝐵 ∧ 𝑧 ∈ 𝐵) → 𝑧 ∈ 𝐵) |
25 | 24 | snssd 4722 |
. . . . 5
⊢ ((𝐴 ≺ 𝐵 ∧ 𝑧 ∈ 𝐵) → {𝑧} ⊆ 𝐵) |
26 | | undif 4396 |
. . . . 5
⊢ ({𝑧} ⊆ 𝐵 ↔ ({𝑧} ∪ (𝐵 ∖ {𝑧})) = 𝐵) |
27 | 25, 26 | sylib 221 |
. . . 4
⊢ ((𝐴 ≺ 𝐵 ∧ 𝑧 ∈ 𝐵) → ({𝑧} ∪ (𝐵 ∖ {𝑧})) = 𝐵) |
28 | 23, 27 | eqtrid 2789 |
. . 3
⊢ ((𝐴 ≺ 𝐵 ∧ 𝑧 ∈ 𝐵) → ((𝐵 ∖ {𝑧}) ∪ {𝑧}) = 𝐵) |
29 | 22, 28 | breqtrd 5079 |
. 2
⊢ ((𝐴 ≺ 𝐵 ∧ 𝑧 ∈ 𝐵) → (𝐴 ∪ {𝐶}) ≼ 𝐵) |
30 | 6, 29 | exlimddv 1943 |
1
⊢ (𝐴 ≺ 𝐵 → (𝐴 ∪ {𝐶}) ≼ 𝐵) |