| Step | Hyp | Ref
 | Expression | 
| 1 |   | oveq2 5930 | 
. . 3
⊢ (𝑛 = 0 → (1...𝑛) = (1...0)) | 
| 2 |   | fveq2 5558 | 
. . 3
⊢ (𝑛 = 0 → (◡𝐺‘𝑛) = (◡𝐺‘0)) | 
| 3 | 1, 2 | breq12d 4046 | 
. 2
⊢ (𝑛 = 0 → ((1...𝑛) ≈ (◡𝐺‘𝑛) ↔ (1...0) ≈ (◡𝐺‘0))) | 
| 4 |   | oveq2 5930 | 
. . 3
⊢ (𝑛 = 𝑚 → (1...𝑛) = (1...𝑚)) | 
| 5 |   | fveq2 5558 | 
. . 3
⊢ (𝑛 = 𝑚 → (◡𝐺‘𝑛) = (◡𝐺‘𝑚)) | 
| 6 | 4, 5 | breq12d 4046 | 
. 2
⊢ (𝑛 = 𝑚 → ((1...𝑛) ≈ (◡𝐺‘𝑛) ↔ (1...𝑚) ≈ (◡𝐺‘𝑚))) | 
| 7 |   | oveq2 5930 | 
. . 3
⊢ (𝑛 = (𝑚 + 1) → (1...𝑛) = (1...(𝑚 + 1))) | 
| 8 |   | fveq2 5558 | 
. . 3
⊢ (𝑛 = (𝑚 + 1) → (◡𝐺‘𝑛) = (◡𝐺‘(𝑚 + 1))) | 
| 9 | 7, 8 | breq12d 4046 | 
. 2
⊢ (𝑛 = (𝑚 + 1) → ((1...𝑛) ≈ (◡𝐺‘𝑛) ↔ (1...(𝑚 + 1)) ≈ (◡𝐺‘(𝑚 + 1)))) | 
| 10 |   | oveq2 5930 | 
. . 3
⊢ (𝑛 = 𝑁 → (1...𝑛) = (1...𝑁)) | 
| 11 |   | fveq2 5558 | 
. . 3
⊢ (𝑛 = 𝑁 → (◡𝐺‘𝑛) = (◡𝐺‘𝑁)) | 
| 12 | 10, 11 | breq12d 4046 | 
. 2
⊢ (𝑛 = 𝑁 → ((1...𝑛) ≈ (◡𝐺‘𝑛) ↔ (1...𝑁) ≈ (◡𝐺‘𝑁))) | 
| 13 |   | 0ex 4160 | 
. . . 4
⊢ ∅
∈ V | 
| 14 | 13 | enref 6824 | 
. . 3
⊢ ∅
≈ ∅ | 
| 15 |   | fz10 10121 | 
. . 3
⊢ (1...0) =
∅ | 
| 16 |   | 0zd 9338 | 
. . . . . . 7
⊢ (⊤
→ 0 ∈ ℤ) | 
| 17 |   | frecfzennn.1 | 
. . . . . . 7
⊢ 𝐺 = frec((𝑥 ∈ ℤ ↦ (𝑥 + 1)), 0) | 
| 18 | 16, 17 | frec2uzf1od 10498 | 
. . . . . 6
⊢ (⊤
→ 𝐺:ω–1-1-onto→(ℤ≥‘0)) | 
| 19 | 18 | mptru 1373 | 
. . . . 5
⊢ 𝐺:ω–1-1-onto→(ℤ≥‘0) | 
| 20 |   | peano1 4630 | 
. . . . 5
⊢ ∅
∈ ω | 
| 21 | 19, 20 | pm3.2i 272 | 
. . . 4
⊢ (𝐺:ω–1-1-onto→(ℤ≥‘0) ∧ ∅
∈ ω) | 
| 22 | 16, 17 | frec2uz0d 10491 | 
. . . . 5
⊢ (⊤
→ (𝐺‘∅) =
0) | 
| 23 | 22 | mptru 1373 | 
. . . 4
⊢ (𝐺‘∅) =
0 | 
| 24 |   | f1ocnvfv 5826 | 
. . . 4
⊢ ((𝐺:ω–1-1-onto→(ℤ≥‘0) ∧ ∅
∈ ω) → ((𝐺‘∅) = 0 → (◡𝐺‘0) = ∅)) | 
| 25 | 21, 23, 24 | mp2 16 | 
. . 3
⊢ (◡𝐺‘0) = ∅ | 
| 26 | 14, 15, 25 | 3brtr4i 4063 | 
. 2
⊢ (1...0)
≈ (◡𝐺‘0) | 
| 27 |   | simpr 110 | 
. . . . 5
⊢ ((𝑚 ∈ ℕ0
∧ (1...𝑚) ≈
(◡𝐺‘𝑚)) → (1...𝑚) ≈ (◡𝐺‘𝑚)) | 
| 28 |   | peano2nn0 9289 | 
. . . . . . 7
⊢ (𝑚 ∈ ℕ0
→ (𝑚 + 1) ∈
ℕ0) | 
| 29 |   | zex 9335 | 
. . . . . . . . . . . . . . 15
⊢ ℤ
∈ V | 
| 30 | 29 | mptex 5788 | 
. . . . . . . . . . . . . 14
⊢ (𝑥 ∈ ℤ ↦ (𝑥 + 1)) ∈ V | 
| 31 |   | vex 2766 | 
. . . . . . . . . . . . . 14
⊢ 𝑧 ∈ V | 
| 32 | 30, 31 | fvex 5578 | 
. . . . . . . . . . . . 13
⊢ ((𝑥 ∈ ℤ ↦ (𝑥 + 1))‘𝑧) ∈ V | 
| 33 | 32 | ax-gen 1463 | 
. . . . . . . . . . . 12
⊢
∀𝑧((𝑥 ∈ ℤ ↦ (𝑥 + 1))‘𝑧) ∈ V | 
| 34 |   | 0z 9337 | 
. . . . . . . . . . . 12
⊢ 0 ∈
ℤ | 
| 35 |   | frecfnom 6459 | 
. . . . . . . . . . . 12
⊢
((∀𝑧((𝑥 ∈ ℤ ↦ (𝑥 + 1))‘𝑧) ∈ V ∧ 0 ∈ ℤ) →
frec((𝑥 ∈ ℤ
↦ (𝑥 + 1)), 0) Fn
ω) | 
| 36 | 33, 34, 35 | mp2an 426 | 
. . . . . . . . . . 11
⊢
frec((𝑥 ∈
ℤ ↦ (𝑥 + 1)),
0) Fn ω | 
| 37 | 17 | fneq1i 5352 | 
. . . . . . . . . . 11
⊢ (𝐺 Fn ω ↔ frec((𝑥 ∈ ℤ ↦ (𝑥 + 1)), 0) Fn
ω) | 
| 38 | 36, 37 | mpbir 146 | 
. . . . . . . . . 10
⊢ 𝐺 Fn ω | 
| 39 |   | omex 4629 | 
. . . . . . . . . 10
⊢ ω
∈ V | 
| 40 |   | fnex 5784 | 
. . . . . . . . . 10
⊢ ((𝐺 Fn ω ∧ ω ∈
V) → 𝐺 ∈
V) | 
| 41 | 38, 39, 40 | mp2an 426 | 
. . . . . . . . 9
⊢ 𝐺 ∈ V | 
| 42 | 41 | cnvex 5208 | 
. . . . . . . 8
⊢ ◡𝐺 ∈ V | 
| 43 |   | vex 2766 | 
. . . . . . . 8
⊢ 𝑚 ∈ V | 
| 44 | 42, 43 | fvex 5578 | 
. . . . . . 7
⊢ (◡𝐺‘𝑚) ∈ V | 
| 45 |   | en2sn 6872 | 
. . . . . . 7
⊢ (((𝑚 + 1) ∈ ℕ0
∧ (◡𝐺‘𝑚) ∈ V) → {(𝑚 + 1)} ≈ {(◡𝐺‘𝑚)}) | 
| 46 | 28, 44, 45 | sylancl 413 | 
. . . . . 6
⊢ (𝑚 ∈ ℕ0
→ {(𝑚 + 1)} ≈
{(◡𝐺‘𝑚)}) | 
| 47 | 46 | adantr 276 | 
. . . . 5
⊢ ((𝑚 ∈ ℕ0
∧ (1...𝑚) ≈
(◡𝐺‘𝑚)) → {(𝑚 + 1)} ≈ {(◡𝐺‘𝑚)}) | 
| 48 |   | fzp1disj 10155 | 
. . . . . 6
⊢
((1...𝑚) ∩
{(𝑚 + 1)}) =
∅ | 
| 49 | 48 | a1i 9 | 
. . . . 5
⊢ ((𝑚 ∈ ℕ0
∧ (1...𝑚) ≈
(◡𝐺‘𝑚)) → ((1...𝑚) ∩ {(𝑚 + 1)}) = ∅) | 
| 50 |   | f1ocnvdm 5828 | 
. . . . . . . . . 10
⊢ ((𝐺:ω–1-1-onto→(ℤ≥‘0) ∧ 𝑚 ∈
(ℤ≥‘0)) → (◡𝐺‘𝑚) ∈ ω) | 
| 51 | 19, 50 | mpan 424 | 
. . . . . . . . 9
⊢ (𝑚 ∈
(ℤ≥‘0) → (◡𝐺‘𝑚) ∈ ω) | 
| 52 |   | nn0uz 9636 | 
. . . . . . . . 9
⊢
ℕ0 = (ℤ≥‘0) | 
| 53 | 51, 52 | eleq2s 2291 | 
. . . . . . . 8
⊢ (𝑚 ∈ ℕ0
→ (◡𝐺‘𝑚) ∈ ω) | 
| 54 |   | nnord 4648 | 
. . . . . . . 8
⊢ ((◡𝐺‘𝑚) ∈ ω → Ord (◡𝐺‘𝑚)) | 
| 55 |   | ordirr 4578 | 
. . . . . . . 8
⊢ (Ord
(◡𝐺‘𝑚) → ¬ (◡𝐺‘𝑚) ∈ (◡𝐺‘𝑚)) | 
| 56 | 53, 54, 55 | 3syl 17 | 
. . . . . . 7
⊢ (𝑚 ∈ ℕ0
→ ¬ (◡𝐺‘𝑚) ∈ (◡𝐺‘𝑚)) | 
| 57 | 56 | adantr 276 | 
. . . . . 6
⊢ ((𝑚 ∈ ℕ0
∧ (1...𝑚) ≈
(◡𝐺‘𝑚)) → ¬ (◡𝐺‘𝑚) ∈ (◡𝐺‘𝑚)) | 
| 58 |   | disjsn 3684 | 
. . . . . 6
⊢ (((◡𝐺‘𝑚) ∩ {(◡𝐺‘𝑚)}) = ∅ ↔ ¬ (◡𝐺‘𝑚) ∈ (◡𝐺‘𝑚)) | 
| 59 | 57, 58 | sylibr 134 | 
. . . . 5
⊢ ((𝑚 ∈ ℕ0
∧ (1...𝑚) ≈
(◡𝐺‘𝑚)) → ((◡𝐺‘𝑚) ∩ {(◡𝐺‘𝑚)}) = ∅) | 
| 60 |   | unen 6875 | 
. . . . 5
⊢
((((1...𝑚) ≈
(◡𝐺‘𝑚) ∧ {(𝑚 + 1)} ≈ {(◡𝐺‘𝑚)}) ∧ (((1...𝑚) ∩ {(𝑚 + 1)}) = ∅ ∧ ((◡𝐺‘𝑚) ∩ {(◡𝐺‘𝑚)}) = ∅)) → ((1...𝑚) ∪ {(𝑚 + 1)}) ≈ ((◡𝐺‘𝑚) ∪ {(◡𝐺‘𝑚)})) | 
| 61 | 27, 47, 49, 59, 60 | syl22anc 1250 | 
. . . 4
⊢ ((𝑚 ∈ ℕ0
∧ (1...𝑚) ≈
(◡𝐺‘𝑚)) → ((1...𝑚) ∪ {(𝑚 + 1)}) ≈ ((◡𝐺‘𝑚) ∪ {(◡𝐺‘𝑚)})) | 
| 62 |   | 1z 9352 | 
. . . . . 6
⊢ 1 ∈
ℤ | 
| 63 |   | 1m1e0 9059 | 
. . . . . . . . . 10
⊢ (1
− 1) = 0 | 
| 64 | 63 | fveq2i 5561 | 
. . . . . . . . 9
⊢
(ℤ≥‘(1 − 1)) =
(ℤ≥‘0) | 
| 65 | 52, 64 | eqtr4i 2220 | 
. . . . . . . 8
⊢
ℕ0 = (ℤ≥‘(1 −
1)) | 
| 66 | 65 | eleq2i 2263 | 
. . . . . . 7
⊢ (𝑚 ∈ ℕ0
↔ 𝑚 ∈
(ℤ≥‘(1 − 1))) | 
| 67 | 66 | biimpi 120 | 
. . . . . 6
⊢ (𝑚 ∈ ℕ0
→ 𝑚 ∈
(ℤ≥‘(1 − 1))) | 
| 68 |   | fzsuc2 10154 | 
. . . . . 6
⊢ ((1
∈ ℤ ∧ 𝑚
∈ (ℤ≥‘(1 − 1))) → (1...(𝑚 + 1)) = ((1...𝑚) ∪ {(𝑚 + 1)})) | 
| 69 | 62, 67, 68 | sylancr 414 | 
. . . . 5
⊢ (𝑚 ∈ ℕ0
→ (1...(𝑚 + 1)) =
((1...𝑚) ∪ {(𝑚 + 1)})) | 
| 70 | 69 | adantr 276 | 
. . . 4
⊢ ((𝑚 ∈ ℕ0
∧ (1...𝑚) ≈
(◡𝐺‘𝑚)) → (1...(𝑚 + 1)) = ((1...𝑚) ∪ {(𝑚 + 1)})) | 
| 71 |   | peano2 4631 | 
. . . . . . . . 9
⊢ ((◡𝐺‘𝑚) ∈ ω → suc (◡𝐺‘𝑚) ∈ ω) | 
| 72 | 53, 71 | syl 14 | 
. . . . . . . 8
⊢ (𝑚 ∈ ℕ0
→ suc (◡𝐺‘𝑚) ∈ ω) | 
| 73 | 72, 19 | jctil 312 | 
. . . . . . 7
⊢ (𝑚 ∈ ℕ0
→ (𝐺:ω–1-1-onto→(ℤ≥‘0) ∧ suc
(◡𝐺‘𝑚) ∈ ω)) | 
| 74 |   | 0zd 9338 | 
. . . . . . . . . 10
⊢ ((◡𝐺‘𝑚) ∈ ω → 0 ∈
ℤ) | 
| 75 |   | id 19 | 
. . . . . . . . . 10
⊢ ((◡𝐺‘𝑚) ∈ ω → (◡𝐺‘𝑚) ∈ ω) | 
| 76 | 74, 17, 75 | frec2uzsucd 10493 | 
. . . . . . . . 9
⊢ ((◡𝐺‘𝑚) ∈ ω → (𝐺‘suc (◡𝐺‘𝑚)) = ((𝐺‘(◡𝐺‘𝑚)) + 1)) | 
| 77 | 53, 76 | syl 14 | 
. . . . . . . 8
⊢ (𝑚 ∈ ℕ0
→ (𝐺‘suc (◡𝐺‘𝑚)) = ((𝐺‘(◡𝐺‘𝑚)) + 1)) | 
| 78 | 52 | eleq2i 2263 | 
. . . . . . . . . . 11
⊢ (𝑚 ∈ ℕ0
↔ 𝑚 ∈
(ℤ≥‘0)) | 
| 79 | 78 | biimpi 120 | 
. . . . . . . . . 10
⊢ (𝑚 ∈ ℕ0
→ 𝑚 ∈
(ℤ≥‘0)) | 
| 80 |   | f1ocnvfv2 5825 | 
. . . . . . . . . 10
⊢ ((𝐺:ω–1-1-onto→(ℤ≥‘0) ∧ 𝑚 ∈
(ℤ≥‘0)) → (𝐺‘(◡𝐺‘𝑚)) = 𝑚) | 
| 81 | 19, 79, 80 | sylancr 414 | 
. . . . . . . . 9
⊢ (𝑚 ∈ ℕ0
→ (𝐺‘(◡𝐺‘𝑚)) = 𝑚) | 
| 82 | 81 | oveq1d 5937 | 
. . . . . . . 8
⊢ (𝑚 ∈ ℕ0
→ ((𝐺‘(◡𝐺‘𝑚)) + 1) = (𝑚 + 1)) | 
| 83 | 77, 82 | eqtrd 2229 | 
. . . . . . 7
⊢ (𝑚 ∈ ℕ0
→ (𝐺‘suc (◡𝐺‘𝑚)) = (𝑚 + 1)) | 
| 84 |   | f1ocnvfv 5826 | 
. . . . . . 7
⊢ ((𝐺:ω–1-1-onto→(ℤ≥‘0) ∧ suc
(◡𝐺‘𝑚) ∈ ω) → ((𝐺‘suc (◡𝐺‘𝑚)) = (𝑚 + 1) → (◡𝐺‘(𝑚 + 1)) = suc (◡𝐺‘𝑚))) | 
| 85 | 73, 83, 84 | sylc 62 | 
. . . . . 6
⊢ (𝑚 ∈ ℕ0
→ (◡𝐺‘(𝑚 + 1)) = suc (◡𝐺‘𝑚)) | 
| 86 | 85 | adantr 276 | 
. . . . 5
⊢ ((𝑚 ∈ ℕ0
∧ (1...𝑚) ≈
(◡𝐺‘𝑚)) → (◡𝐺‘(𝑚 + 1)) = suc (◡𝐺‘𝑚)) | 
| 87 |   | df-suc 4406 | 
. . . . 5
⊢ suc
(◡𝐺‘𝑚) = ((◡𝐺‘𝑚) ∪ {(◡𝐺‘𝑚)}) | 
| 88 | 86, 87 | eqtrdi 2245 | 
. . . 4
⊢ ((𝑚 ∈ ℕ0
∧ (1...𝑚) ≈
(◡𝐺‘𝑚)) → (◡𝐺‘(𝑚 + 1)) = ((◡𝐺‘𝑚) ∪ {(◡𝐺‘𝑚)})) | 
| 89 | 61, 70, 88 | 3brtr4d 4065 | 
. . 3
⊢ ((𝑚 ∈ ℕ0
∧ (1...𝑚) ≈
(◡𝐺‘𝑚)) → (1...(𝑚 + 1)) ≈ (◡𝐺‘(𝑚 + 1))) | 
| 90 | 89 | ex 115 | 
. 2
⊢ (𝑚 ∈ ℕ0
→ ((1...𝑚) ≈
(◡𝐺‘𝑚) → (1...(𝑚 + 1)) ≈ (◡𝐺‘(𝑚 + 1)))) | 
| 91 | 3, 6, 9, 12, 26, 90 | nn0ind 9440 | 
1
⊢ (𝑁 ∈ ℕ0
→ (1...𝑁) ≈
(◡𝐺‘𝑁)) |