Proof of Theorem fzsuc2
| Step | Hyp | Ref
 | Expression | 
| 1 |   | uzp1 9635 | 
. 2
⊢ (𝑁 ∈
(ℤ≥‘(𝑀 − 1)) → (𝑁 = (𝑀 − 1) ∨ 𝑁 ∈
(ℤ≥‘((𝑀 − 1) + 1)))) | 
| 2 |   | zcn 9331 | 
. . . . . . . 8
⊢ (𝑀 ∈ ℤ → 𝑀 ∈
ℂ) | 
| 3 |   | ax-1cn 7972 | 
. . . . . . . 8
⊢ 1 ∈
ℂ | 
| 4 |   | npcan 8235 | 
. . . . . . . 8
⊢ ((𝑀 ∈ ℂ ∧ 1 ∈
ℂ) → ((𝑀 −
1) + 1) = 𝑀) | 
| 5 | 2, 3, 4 | sylancl 413 | 
. . . . . . 7
⊢ (𝑀 ∈ ℤ → ((𝑀 − 1) + 1) = 𝑀) | 
| 6 | 5 | oveq2d 5938 | 
. . . . . 6
⊢ (𝑀 ∈ ℤ → (𝑀...((𝑀 − 1) + 1)) = (𝑀...𝑀)) | 
| 7 |   | uncom 3307 | 
. . . . . . . 8
⊢ (∅
∪ {𝑀}) = ({𝑀} ∪
∅) | 
| 8 |   | un0 3484 | 
. . . . . . . 8
⊢ ({𝑀} ∪ ∅) = {𝑀} | 
| 9 | 7, 8 | eqtri 2217 | 
. . . . . . 7
⊢ (∅
∪ {𝑀}) = {𝑀} | 
| 10 |   | zre 9330 | 
. . . . . . . . . 10
⊢ (𝑀 ∈ ℤ → 𝑀 ∈
ℝ) | 
| 11 | 10 | ltm1d 8959 | 
. . . . . . . . 9
⊢ (𝑀 ∈ ℤ → (𝑀 − 1) < 𝑀) | 
| 12 |   | peano2zm 9364 | 
. . . . . . . . . 10
⊢ (𝑀 ∈ ℤ → (𝑀 − 1) ∈
ℤ) | 
| 13 |   | fzn 10117 | 
. . . . . . . . . 10
⊢ ((𝑀 ∈ ℤ ∧ (𝑀 − 1) ∈ ℤ)
→ ((𝑀 − 1) <
𝑀 ↔ (𝑀...(𝑀 − 1)) = ∅)) | 
| 14 | 12, 13 | mpdan 421 | 
. . . . . . . . 9
⊢ (𝑀 ∈ ℤ → ((𝑀 − 1) < 𝑀 ↔ (𝑀...(𝑀 − 1)) = ∅)) | 
| 15 | 11, 14 | mpbid 147 | 
. . . . . . . 8
⊢ (𝑀 ∈ ℤ → (𝑀...(𝑀 − 1)) = ∅) | 
| 16 | 5 | sneqd 3635 | 
. . . . . . . 8
⊢ (𝑀 ∈ ℤ → {((𝑀 − 1) + 1)} = {𝑀}) | 
| 17 | 15, 16 | uneq12d 3318 | 
. . . . . . 7
⊢ (𝑀 ∈ ℤ → ((𝑀...(𝑀 − 1)) ∪ {((𝑀 − 1) + 1)}) = (∅ ∪ {𝑀})) | 
| 18 |   | fzsn 10141 | 
. . . . . . 7
⊢ (𝑀 ∈ ℤ → (𝑀...𝑀) = {𝑀}) | 
| 19 | 9, 17, 18 | 3eqtr4a 2255 | 
. . . . . 6
⊢ (𝑀 ∈ ℤ → ((𝑀...(𝑀 − 1)) ∪ {((𝑀 − 1) + 1)}) = (𝑀...𝑀)) | 
| 20 | 6, 19 | eqtr4d 2232 | 
. . . . 5
⊢ (𝑀 ∈ ℤ → (𝑀...((𝑀 − 1) + 1)) = ((𝑀...(𝑀 − 1)) ∪ {((𝑀 − 1) + 1)})) | 
| 21 |   | oveq1 5929 | 
. . . . . . 7
⊢ (𝑁 = (𝑀 − 1) → (𝑁 + 1) = ((𝑀 − 1) + 1)) | 
| 22 | 21 | oveq2d 5938 | 
. . . . . 6
⊢ (𝑁 = (𝑀 − 1) → (𝑀...(𝑁 + 1)) = (𝑀...((𝑀 − 1) + 1))) | 
| 23 |   | oveq2 5930 | 
. . . . . . 7
⊢ (𝑁 = (𝑀 − 1) → (𝑀...𝑁) = (𝑀...(𝑀 − 1))) | 
| 24 | 21 | sneqd 3635 | 
. . . . . . 7
⊢ (𝑁 = (𝑀 − 1) → {(𝑁 + 1)} = {((𝑀 − 1) + 1)}) | 
| 25 | 23, 24 | uneq12d 3318 | 
. . . . . 6
⊢ (𝑁 = (𝑀 − 1) → ((𝑀...𝑁) ∪ {(𝑁 + 1)}) = ((𝑀...(𝑀 − 1)) ∪ {((𝑀 − 1) + 1)})) | 
| 26 | 22, 25 | eqeq12d 2211 | 
. . . . 5
⊢ (𝑁 = (𝑀 − 1) → ((𝑀...(𝑁 + 1)) = ((𝑀...𝑁) ∪ {(𝑁 + 1)}) ↔ (𝑀...((𝑀 − 1) + 1)) = ((𝑀...(𝑀 − 1)) ∪ {((𝑀 − 1) + 1)}))) | 
| 27 | 20, 26 | syl5ibrcom 157 | 
. . . 4
⊢ (𝑀 ∈ ℤ → (𝑁 = (𝑀 − 1) → (𝑀...(𝑁 + 1)) = ((𝑀...𝑁) ∪ {(𝑁 + 1)}))) | 
| 28 | 27 | imp 124 | 
. . 3
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 = (𝑀 − 1)) → (𝑀...(𝑁 + 1)) = ((𝑀...𝑁) ∪ {(𝑁 + 1)})) | 
| 29 | 5 | fveq2d 5562 | 
. . . . . 6
⊢ (𝑀 ∈ ℤ →
(ℤ≥‘((𝑀 − 1) + 1)) =
(ℤ≥‘𝑀)) | 
| 30 | 29 | eleq2d 2266 | 
. . . . 5
⊢ (𝑀 ∈ ℤ → (𝑁 ∈
(ℤ≥‘((𝑀 − 1) + 1)) ↔ 𝑁 ∈ (ℤ≥‘𝑀))) | 
| 31 | 30 | biimpa 296 | 
. . . 4
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈
(ℤ≥‘((𝑀 − 1) + 1))) → 𝑁 ∈ (ℤ≥‘𝑀)) | 
| 32 |   | fzsuc 10144 | 
. . . 4
⊢ (𝑁 ∈
(ℤ≥‘𝑀) → (𝑀...(𝑁 + 1)) = ((𝑀...𝑁) ∪ {(𝑁 + 1)})) | 
| 33 | 31, 32 | syl 14 | 
. . 3
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈
(ℤ≥‘((𝑀 − 1) + 1))) → (𝑀...(𝑁 + 1)) = ((𝑀...𝑁) ∪ {(𝑁 + 1)})) | 
| 34 | 28, 33 | jaodan 798 | 
. 2
⊢ ((𝑀 ∈ ℤ ∧ (𝑁 = (𝑀 − 1) ∨ 𝑁 ∈
(ℤ≥‘((𝑀 − 1) + 1)))) → (𝑀...(𝑁 + 1)) = ((𝑀...𝑁) ∪ {(𝑁 + 1)})) | 
| 35 | 1, 34 | sylan2 286 | 
1
⊢ ((𝑀 ∈ ℤ ∧ 𝑁 ∈
(ℤ≥‘(𝑀 − 1))) → (𝑀...(𝑁 + 1)) = ((𝑀...𝑁) ∪ {(𝑁 + 1)})) |