| Step | Hyp | Ref
 | Expression | 
| 1 |   | 0lt1o 6498 | 
. . . . . . . . . 10
⊢ ∅
∈ 1o | 
| 2 |   | djurcl 7118 | 
. . . . . . . . . 10
⊢ (∅
∈ 1o → (inr‘∅) ∈ (𝐴 ⊔ 1o)) | 
| 3 | 1, 2 | ax-mp 5 | 
. . . . . . . . 9
⊢
(inr‘∅) ∈ (𝐴 ⊔ 1o) | 
| 4 | 3 | a1i 9 | 
. . . . . . . 8
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑛 ∈ ω) ∧ 𝑛 = ∅) → (inr‘∅) ∈
(𝐴 ⊔
1o)) | 
| 5 |   | simpllr 534 | 
. . . . . . . . . . 11
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑛 ∈ ω) ∧ ¬ 𝑛 = ∅) → 𝑓:ω–onto→𝐴) | 
| 6 |   | fof 5480 | 
. . . . . . . . . . 11
⊢ (𝑓:ω–onto→𝐴 → 𝑓:ω⟶𝐴) | 
| 7 | 5, 6 | syl 14 | 
. . . . . . . . . 10
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑛 ∈ ω) ∧ ¬ 𝑛 = ∅) → 𝑓:ω⟶𝐴) | 
| 8 |   | nnpredcl 4659 | 
. . . . . . . . . . 11
⊢ (𝑛 ∈ ω → ∪ 𝑛
∈ ω) | 
| 9 | 8 | ad2antlr 489 | 
. . . . . . . . . 10
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑛 ∈ ω) ∧ ¬ 𝑛 = ∅) → ∪ 𝑛
∈ ω) | 
| 10 | 7, 9 | ffvelcdmd 5698 | 
. . . . . . . . 9
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑛 ∈ ω) ∧ ¬ 𝑛 = ∅) → (𝑓‘∪ 𝑛)
∈ 𝐴) | 
| 11 |   | djulcl 7117 | 
. . . . . . . . 9
⊢ ((𝑓‘∪ 𝑛)
∈ 𝐴 →
(inl‘(𝑓‘∪ 𝑛))
∈ (𝐴 ⊔
1o)) | 
| 12 | 10, 11 | syl 14 | 
. . . . . . . 8
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑛 ∈ ω) ∧ ¬ 𝑛 = ∅) →
(inl‘(𝑓‘∪ 𝑛))
∈ (𝐴 ⊔
1o)) | 
| 13 |   | nndceq0 4654 | 
. . . . . . . . 9
⊢ (𝑛 ∈ ω →
DECID 𝑛 =
∅) | 
| 14 | 13 | adantl 277 | 
. . . . . . . 8
⊢
(((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑛 ∈ ω) → DECID
𝑛 =
∅) | 
| 15 | 4, 12, 14 | ifcldadc 3590 | 
. . . . . . 7
⊢
(((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑛 ∈ ω) → if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))
∈ (𝐴 ⊔
1o)) | 
| 16 | 15 | fmpttd 5717 | 
. . . . . 6
⊢
((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) → (𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))):ω⟶(𝐴 ⊔ 1o)) | 
| 17 |   | simpllr 534 | 
. . . . . . . . . . 11
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) → 𝑓:ω–onto→𝐴) | 
| 18 |   | simprl 529 | 
. . . . . . . . . . 11
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) → 𝑤 ∈ 𝐴) | 
| 19 |   | foelrn 5799 | 
. . . . . . . . . . 11
⊢ ((𝑓:ω–onto→𝐴 ∧ 𝑤 ∈ 𝐴) → ∃𝑢 ∈ ω 𝑤 = (𝑓‘𝑢)) | 
| 20 | 17, 18, 19 | syl2anc 411 | 
. . . . . . . . . 10
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) → ∃𝑢 ∈ ω 𝑤 = (𝑓‘𝑢)) | 
| 21 |   | peano2 4631 | 
. . . . . . . . . . . 12
⊢ (𝑢 ∈ ω → suc 𝑢 ∈
ω) | 
| 22 | 21 | ad2antrl 490 | 
. . . . . . . . . . 11
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → suc 𝑢 ∈ ω) | 
| 23 |   | simplrr 536 | 
. . . . . . . . . . . . . 14
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → 𝑦 = (inl‘𝑤)) | 
| 24 |   | simprl 529 | 
. . . . . . . . . . . . . . . . . . 19
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → 𝑢 ∈ ω) | 
| 25 |   | nnord 4648 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (𝑢 ∈ ω → Ord 𝑢) | 
| 26 |   | ordtr 4413 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (Ord
𝑢 → Tr 𝑢) | 
| 27 | 24, 25, 26 | 3syl 17 | 
. . . . . . . . . . . . . . . . . 18
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → Tr 𝑢) | 
| 28 |   | unisucg 4449 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (𝑢 ∈ ω → (Tr 𝑢 ↔ ∪ suc 𝑢 = 𝑢)) | 
| 29 | 28 | ad2antrl 490 | 
. . . . . . . . . . . . . . . . . 18
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → (Tr 𝑢 ↔ ∪ suc
𝑢 = 𝑢)) | 
| 30 | 27, 29 | mpbid 147 | 
. . . . . . . . . . . . . . . . 17
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → ∪ suc
𝑢 = 𝑢) | 
| 31 | 30 | fveq2d 5562 | 
. . . . . . . . . . . . . . . 16
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → (𝑓‘∪ suc 𝑢) = (𝑓‘𝑢)) | 
| 32 |   | simprr 531 | 
. . . . . . . . . . . . . . . 16
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → 𝑤 = (𝑓‘𝑢)) | 
| 33 | 31, 32 | eqtr4d 2232 | 
. . . . . . . . . . . . . . 15
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → (𝑓‘∪ suc 𝑢) = 𝑤) | 
| 34 | 33 | fveq2d 5562 | 
. . . . . . . . . . . . . 14
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → (inl‘(𝑓‘∪ suc 𝑢)) = (inl‘𝑤)) | 
| 35 | 23, 34 | eqtr4d 2232 | 
. . . . . . . . . . . . 13
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → 𝑦 = (inl‘(𝑓‘∪ suc 𝑢))) | 
| 36 |   | peano3 4632 | 
. . . . . . . . . . . . . . . 16
⊢ (𝑢 ∈ ω → suc 𝑢 ≠ ∅) | 
| 37 | 36 | neneqd 2388 | 
. . . . . . . . . . . . . . 15
⊢ (𝑢 ∈ ω → ¬ suc
𝑢 =
∅) | 
| 38 | 37 | ad2antrl 490 | 
. . . . . . . . . . . . . 14
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → ¬ suc 𝑢 = ∅) | 
| 39 | 38 | iffalsed 3571 | 
. . . . . . . . . . . . 13
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → if(suc 𝑢 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ suc 𝑢))) = (inl‘(𝑓‘∪ suc 𝑢))) | 
| 40 | 35, 39 | eqtr4d 2232 | 
. . . . . . . . . . . 12
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → 𝑦 = if(suc 𝑢 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ suc 𝑢)))) | 
| 41 |   | eqid 2196 | 
. . . . . . . . . . . . 13
⊢ (𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))) = (𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))) | 
| 42 |   | eqeq1 2203 | 
. . . . . . . . . . . . . 14
⊢ (𝑛 = suc 𝑢 → (𝑛 = ∅ ↔ suc 𝑢 = ∅)) | 
| 43 |   | unieq 3848 | 
. . . . . . . . . . . . . . . 16
⊢ (𝑛 = suc 𝑢 → ∪ 𝑛 = ∪
suc 𝑢) | 
| 44 | 43 | fveq2d 5562 | 
. . . . . . . . . . . . . . 15
⊢ (𝑛 = suc 𝑢 → (𝑓‘∪ 𝑛) = (𝑓‘∪ suc 𝑢)) | 
| 45 | 44 | fveq2d 5562 | 
. . . . . . . . . . . . . 14
⊢ (𝑛 = suc 𝑢 → (inl‘(𝑓‘∪ 𝑛)) = (inl‘(𝑓‘∪ suc 𝑢))) | 
| 46 | 42, 45 | ifbieq2d 3585 | 
. . . . . . . . . . . . 13
⊢ (𝑛 = suc 𝑢 → if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))
= if(suc 𝑢 = ∅,
(inr‘∅), (inl‘(𝑓‘∪ suc 𝑢)))) | 
| 47 |   | simpllr 534 | 
. . . . . . . . . . . . . 14
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → 𝑦 ∈ (𝐴 ⊔ 1o)) | 
| 48 | 40, 47 | eqeltrrd 2274 | 
. . . . . . . . . . . . 13
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → if(suc 𝑢 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ suc 𝑢))) ∈ (𝐴 ⊔ 1o)) | 
| 49 | 41, 46, 22, 48 | fvmptd3 5655 | 
. . . . . . . . . . . 12
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘suc 𝑢) = if(suc 𝑢 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ suc 𝑢)))) | 
| 50 | 40, 49 | eqtr4d 2232 | 
. . . . . . . . . . 11
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → 𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘suc 𝑢)) | 
| 51 |   | fveq2 5558 | 
. . . . . . . . . . . 12
⊢ (𝑧 = suc 𝑢 → ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧) = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘suc 𝑢)) | 
| 52 | 51 | rspceeqv 2886 | 
. . . . . . . . . . 11
⊢ ((suc
𝑢 ∈ ω ∧
𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘suc 𝑢)) → ∃𝑧 ∈ ω 𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧)) | 
| 53 | 22, 50, 52 | syl2anc 411 | 
. . . . . . . . . 10
⊢
(((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) ∧ (𝑢 ∈ ω ∧ 𝑤 = (𝑓‘𝑢))) → ∃𝑧 ∈ ω 𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧)) | 
| 54 | 20, 53 | rexlimddv 2619 | 
. . . . . . . . 9
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 𝐴 ∧ 𝑦 = (inl‘𝑤))) → ∃𝑧 ∈ ω 𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧)) | 
| 55 | 54 | rexlimdvaa 2615 | 
. . . . . . . 8
⊢
(((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) →
(∃𝑤 ∈ 𝐴 𝑦 = (inl‘𝑤) → ∃𝑧 ∈ ω 𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧))) | 
| 56 |   | peano1 4630 | 
. . . . . . . . . 10
⊢ ∅
∈ ω | 
| 57 |   | simprr 531 | 
. . . . . . . . . . . . 13
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 1o ∧
𝑦 = (inr‘𝑤))) → 𝑦 = (inr‘𝑤)) | 
| 58 |   | simprl 529 | 
. . . . . . . . . . . . . . 15
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 1o ∧
𝑦 = (inr‘𝑤))) → 𝑤 ∈ 1o) | 
| 59 |   | el1o 6495 | 
. . . . . . . . . . . . . . 15
⊢ (𝑤 ∈ 1o ↔
𝑤 =
∅) | 
| 60 | 58, 59 | sylib 122 | 
. . . . . . . . . . . . . 14
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 1o ∧
𝑦 = (inr‘𝑤))) → 𝑤 = ∅) | 
| 61 | 60 | fveq2d 5562 | 
. . . . . . . . . . . . 13
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 1o ∧
𝑦 = (inr‘𝑤))) → (inr‘𝑤) =
(inr‘∅)) | 
| 62 | 57, 61 | eqtrd 2229 | 
. . . . . . . . . . . 12
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 1o ∧
𝑦 = (inr‘𝑤))) → 𝑦 = (inr‘∅)) | 
| 63 |   | eqid 2196 | 
. . . . . . . . . . . . 13
⊢ ∅ =
∅ | 
| 64 | 63 | iftruei 3567 | 
. . . . . . . . . . . 12
⊢
if(∅ = ∅, (inr‘∅), (inl‘(𝑓‘∪ ∅))) = (inr‘∅) | 
| 65 | 62, 64 | eqtr4di 2247 | 
. . . . . . . . . . 11
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 1o ∧
𝑦 = (inr‘𝑤))) → 𝑦 = if(∅ = ∅, (inr‘∅),
(inl‘(𝑓‘∪ ∅)))) | 
| 66 | 64, 3 | eqeltri 2269 | 
. . . . . . . . . . . . 13
⊢
if(∅ = ∅, (inr‘∅), (inl‘(𝑓‘∪ ∅))) ∈ (𝐴 ⊔ 1o) | 
| 67 | 66 | a1i 9 | 
. . . . . . . . . . . 12
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 1o ∧
𝑦 = (inr‘𝑤))) → if(∅ = ∅,
(inr‘∅), (inl‘(𝑓‘∪
∅))) ∈ (𝐴
⊔ 1o)) | 
| 68 |   | eqeq1 2203 | 
. . . . . . . . . . . . . 14
⊢ (𝑛 = ∅ → (𝑛 = ∅ ↔ ∅ =
∅)) | 
| 69 |   | unieq 3848 | 
. . . . . . . . . . . . . . . 16
⊢ (𝑛 = ∅ → ∪ 𝑛 =
∪ ∅) | 
| 70 | 69 | fveq2d 5562 | 
. . . . . . . . . . . . . . 15
⊢ (𝑛 = ∅ → (𝑓‘∪ 𝑛) =
(𝑓‘∪ ∅)) | 
| 71 | 70 | fveq2d 5562 | 
. . . . . . . . . . . . . 14
⊢ (𝑛 = ∅ →
(inl‘(𝑓‘∪ 𝑛))
= (inl‘(𝑓‘∪ ∅))) | 
| 72 | 68, 71 | ifbieq2d 3585 | 
. . . . . . . . . . . . 13
⊢ (𝑛 = ∅ → if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))
= if(∅ = ∅, (inr‘∅), (inl‘(𝑓‘∪
∅)))) | 
| 73 | 72, 41 | fvmptg 5637 | 
. . . . . . . . . . . 12
⊢ ((∅
∈ ω ∧ if(∅ = ∅, (inr‘∅),
(inl‘(𝑓‘∪ ∅))) ∈ (𝐴 ⊔ 1o)) → ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘∅) = if(∅ = ∅,
(inr‘∅), (inl‘(𝑓‘∪
∅)))) | 
| 74 | 56, 67, 73 | sylancr 414 | 
. . . . . . . . . . 11
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 1o ∧
𝑦 = (inr‘𝑤))) → ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘∅) = if(∅ = ∅,
(inr‘∅), (inl‘(𝑓‘∪
∅)))) | 
| 75 | 65, 74 | eqtr4d 2232 | 
. . . . . . . . . 10
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 1o ∧
𝑦 = (inr‘𝑤))) → 𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘∅)) | 
| 76 |   | fveq2 5558 | 
. . . . . . . . . . 11
⊢ (𝑧 = ∅ → ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧) = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘∅)) | 
| 77 | 76 | rspceeqv 2886 | 
. . . . . . . . . 10
⊢ ((∅
∈ ω ∧ 𝑦 =
((𝑛 ∈ ω ↦
if(𝑛 = ∅,
(inr‘∅), (inl‘(𝑓‘∪ 𝑛))))‘∅)) →
∃𝑧 ∈ ω
𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧)) | 
| 78 | 56, 75, 77 | sylancr 414 | 
. . . . . . . . 9
⊢
((((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) ∧ (𝑤 ∈ 1o ∧
𝑦 = (inr‘𝑤))) → ∃𝑧 ∈ ω 𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧)) | 
| 79 | 78 | rexlimdvaa 2615 | 
. . . . . . . 8
⊢
(((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) →
(∃𝑤 ∈
1o 𝑦 =
(inr‘𝑤) →
∃𝑧 ∈ ω
𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧))) | 
| 80 |   | djur 7135 | 
. . . . . . . . . 10
⊢ (𝑦 ∈ (𝐴 ⊔ 1o) ↔
(∃𝑤 ∈ 𝐴 𝑦 = (inl‘𝑤) ∨ ∃𝑤 ∈ 1o 𝑦 = (inr‘𝑤))) | 
| 81 | 80 | biimpi 120 | 
. . . . . . . . 9
⊢ (𝑦 ∈ (𝐴 ⊔ 1o) →
(∃𝑤 ∈ 𝐴 𝑦 = (inl‘𝑤) ∨ ∃𝑤 ∈ 1o 𝑦 = (inr‘𝑤))) | 
| 82 | 81 | adantl 277 | 
. . . . . . . 8
⊢
(((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) →
(∃𝑤 ∈ 𝐴 𝑦 = (inl‘𝑤) ∨ ∃𝑤 ∈ 1o 𝑦 = (inr‘𝑤))) | 
| 83 | 55, 79, 82 | mpjaod 719 | 
. . . . . . 7
⊢
(((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) ∧ 𝑦 ∈ (𝐴 ⊔ 1o)) →
∃𝑧 ∈ ω
𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧)) | 
| 84 | 83 | ralrimiva 2570 | 
. . . . . 6
⊢
((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) → ∀𝑦 ∈ (𝐴 ⊔ 1o)∃𝑧 ∈ ω 𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧)) | 
| 85 |   | dffo3 5709 | 
. . . . . 6
⊢ ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))):ω–onto→(𝐴 ⊔ 1o) ↔ ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))):ω⟶(𝐴 ⊔ 1o) ∧ ∀𝑦 ∈ (𝐴 ⊔ 1o)∃𝑧 ∈ ω 𝑦 = ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛))))‘𝑧))) | 
| 86 | 16, 84, 85 | sylanbrc 417 | 
. . . . 5
⊢
((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) → (𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))):ω–onto→(𝐴 ⊔ 1o)) | 
| 87 |   | omex 4629 | 
. . . . . . 7
⊢ ω
∈ V | 
| 88 | 87 | mptex 5788 | 
. . . . . 6
⊢ (𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))) ∈ V | 
| 89 |   | foeq1 5476 | 
. . . . . 6
⊢ (𝑔 = (𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))) → (𝑔:ω–onto→(𝐴 ⊔ 1o) ↔ (𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))):ω–onto→(𝐴 ⊔ 1o))) | 
| 90 | 88, 89 | spcev 2859 | 
. . . . 5
⊢ ((𝑛 ∈ ω ↦ if(𝑛 = ∅, (inr‘∅),
(inl‘(𝑓‘∪ 𝑛)))):ω–onto→(𝐴 ⊔ 1o) → ∃𝑔 𝑔:ω–onto→(𝐴 ⊔ 1o)) | 
| 91 | 86, 90 | syl 14 | 
. . . 4
⊢
((∃𝑥 𝑥 ∈ 𝐴 ∧ 𝑓:ω–onto→𝐴) → ∃𝑔 𝑔:ω–onto→(𝐴 ⊔ 1o)) | 
| 92 | 91 | ex 115 | 
. . 3
⊢
(∃𝑥 𝑥 ∈ 𝐴 → (𝑓:ω–onto→𝐴 → ∃𝑔 𝑔:ω–onto→(𝐴 ⊔ 1o))) | 
| 93 | 92 | exlimdv 1833 | 
. 2
⊢
(∃𝑥 𝑥 ∈ 𝐴 → (∃𝑓 𝑓:ω–onto→𝐴 → ∃𝑔 𝑔:ω–onto→(𝐴 ⊔ 1o))) | 
| 94 |   | foeq1 5476 | 
. . 3
⊢ (𝑓 = 𝑔 → (𝑓:ω–onto→(𝐴 ⊔ 1o) ↔ 𝑔:ω–onto→(𝐴 ⊔ 1o))) | 
| 95 | 94 | cbvexv 1933 | 
. 2
⊢
(∃𝑓 𝑓:ω–onto→(𝐴 ⊔ 1o) ↔ ∃𝑔 𝑔:ω–onto→(𝐴 ⊔ 1o)) | 
| 96 | 93, 95 | imbitrrdi 162 | 
1
⊢
(∃𝑥 𝑥 ∈ 𝐴 → (∃𝑓 𝑓:ω–onto→𝐴 → ∃𝑓 𝑓:ω–onto→(𝐴 ⊔ 1o))) |