| Step | Hyp | Ref
| Expression |
| 1 | | df-proddc 11716 |
. 2
⊢
∏𝑘 ∈
𝐴 𝐵 = (℩𝑥(∃𝑚 ∈ ℤ ((𝐴 ⊆ (ℤ≥‘𝑚) ∧ ∀𝑗 ∈
(ℤ≥‘𝑚)DECID 𝑗 ∈ 𝐴) ∧ (∃𝑛 ∈ (ℤ≥‘𝑚)∃𝑦(𝑦 # 0 ∧ seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦) ∧ seq𝑚( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑥)) ∨ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto→𝐴 ∧ 𝑥 = (seq1( · , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 𝑚, ⦋(𝑓‘𝑛) / 𝑘⦌𝐵, 1)))‘𝑚)))) |
| 2 | | nfcv 2339 |
. . . . 5
⊢
Ⅎ𝑘ℤ |
| 3 | | nfcprod1.1 |
. . . . . . . 8
⊢
Ⅎ𝑘𝐴 |
| 4 | | nfcv 2339 |
. . . . . . . 8
⊢
Ⅎ𝑘(ℤ≥‘𝑚) |
| 5 | 3, 4 | nfss 3176 |
. . . . . . 7
⊢
Ⅎ𝑘 𝐴 ⊆
(ℤ≥‘𝑚) |
| 6 | 3 | nfcri 2333 |
. . . . . . . . 9
⊢
Ⅎ𝑘 𝑗 ∈ 𝐴 |
| 7 | 6 | nfdc 1673 |
. . . . . . . 8
⊢
Ⅎ𝑘DECID 𝑗 ∈ 𝐴 |
| 8 | 4, 7 | nfralxy 2535 |
. . . . . . 7
⊢
Ⅎ𝑘∀𝑗 ∈ (ℤ≥‘𝑚)DECID 𝑗 ∈ 𝐴 |
| 9 | 5, 8 | nfan 1579 |
. . . . . 6
⊢
Ⅎ𝑘(𝐴 ⊆
(ℤ≥‘𝑚) ∧ ∀𝑗 ∈ (ℤ≥‘𝑚)DECID 𝑗 ∈ 𝐴) |
| 10 | | nfv 1542 |
. . . . . . . . . 10
⊢
Ⅎ𝑘 𝑦 # 0 |
| 11 | | nfcv 2339 |
. . . . . . . . . . . 12
⊢
Ⅎ𝑘𝑛 |
| 12 | | nfcv 2339 |
. . . . . . . . . . . 12
⊢
Ⅎ𝑘
· |
| 13 | | nfmpt1 4126 |
. . . . . . . . . . . 12
⊢
Ⅎ𝑘(𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1)) |
| 14 | 11, 12, 13 | nfseq 10549 |
. . . . . . . . . . 11
⊢
Ⅎ𝑘seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) |
| 15 | | nfcv 2339 |
. . . . . . . . . . 11
⊢
Ⅎ𝑘
⇝ |
| 16 | | nfcv 2339 |
. . . . . . . . . . 11
⊢
Ⅎ𝑘𝑦 |
| 17 | 14, 15, 16 | nfbr 4079 |
. . . . . . . . . 10
⊢
Ⅎ𝑘seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦 |
| 18 | 10, 17 | nfan 1579 |
. . . . . . . . 9
⊢
Ⅎ𝑘(𝑦 # 0 ∧ seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦) |
| 19 | 18 | nfex 1651 |
. . . . . . . 8
⊢
Ⅎ𝑘∃𝑦(𝑦 # 0 ∧ seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦) |
| 20 | 4, 19 | nfrexw 2536 |
. . . . . . 7
⊢
Ⅎ𝑘∃𝑛 ∈
(ℤ≥‘𝑚)∃𝑦(𝑦 # 0 ∧ seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦) |
| 21 | | nfcv 2339 |
. . . . . . . . 9
⊢
Ⅎ𝑘𝑚 |
| 22 | 21, 12, 13 | nfseq 10549 |
. . . . . . . 8
⊢
Ⅎ𝑘seq𝑚( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) |
| 23 | | nfcv 2339 |
. . . . . . . 8
⊢
Ⅎ𝑘𝑥 |
| 24 | 22, 15, 23 | nfbr 4079 |
. . . . . . 7
⊢
Ⅎ𝑘seq𝑚( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑥 |
| 25 | 20, 24 | nfan 1579 |
. . . . . 6
⊢
Ⅎ𝑘(∃𝑛 ∈ (ℤ≥‘𝑚)∃𝑦(𝑦 # 0 ∧ seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦) ∧ seq𝑚( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑥) |
| 26 | 9, 25 | nfan 1579 |
. . . . 5
⊢
Ⅎ𝑘((𝐴 ⊆
(ℤ≥‘𝑚) ∧ ∀𝑗 ∈ (ℤ≥‘𝑚)DECID 𝑗 ∈ 𝐴) ∧ (∃𝑛 ∈ (ℤ≥‘𝑚)∃𝑦(𝑦 # 0 ∧ seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦) ∧ seq𝑚( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑥)) |
| 27 | 2, 26 | nfrexw 2536 |
. . . 4
⊢
Ⅎ𝑘∃𝑚 ∈ ℤ ((𝐴 ⊆
(ℤ≥‘𝑚) ∧ ∀𝑗 ∈ (ℤ≥‘𝑚)DECID 𝑗 ∈ 𝐴) ∧ (∃𝑛 ∈ (ℤ≥‘𝑚)∃𝑦(𝑦 # 0 ∧ seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦) ∧ seq𝑚( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑥)) |
| 28 | | nfcv 2339 |
. . . . 5
⊢
Ⅎ𝑘ℕ |
| 29 | | nfcv 2339 |
. . . . . . . 8
⊢
Ⅎ𝑘𝑓 |
| 30 | | nfcv 2339 |
. . . . . . . 8
⊢
Ⅎ𝑘(1...𝑚) |
| 31 | 29, 30, 3 | nff1o 5502 |
. . . . . . 7
⊢
Ⅎ𝑘 𝑓:(1...𝑚)–1-1-onto→𝐴 |
| 32 | | nfcv 2339 |
. . . . . . . . . 10
⊢
Ⅎ𝑘1 |
| 33 | | nfv 1542 |
. . . . . . . . . . . 12
⊢
Ⅎ𝑘 𝑛 ≤ 𝑚 |
| 34 | | nfcsb1v 3117 |
. . . . . . . . . . . 12
⊢
Ⅎ𝑘⦋(𝑓‘𝑛) / 𝑘⦌𝐵 |
| 35 | 33, 34, 32 | nfif 3589 |
. . . . . . . . . . 11
⊢
Ⅎ𝑘if(𝑛 ≤ 𝑚, ⦋(𝑓‘𝑛) / 𝑘⦌𝐵, 1) |
| 36 | 28, 35 | nfmpt 4125 |
. . . . . . . . . 10
⊢
Ⅎ𝑘(𝑛 ∈ ℕ ↦ if(𝑛 ≤ 𝑚, ⦋(𝑓‘𝑛) / 𝑘⦌𝐵, 1)) |
| 37 | 32, 12, 36 | nfseq 10549 |
. . . . . . . . 9
⊢
Ⅎ𝑘seq1(
· , (𝑛 ∈
ℕ ↦ if(𝑛 ≤
𝑚, ⦋(𝑓‘𝑛) / 𝑘⦌𝐵, 1))) |
| 38 | 37, 21 | nffv 5568 |
. . . . . . . 8
⊢
Ⅎ𝑘(seq1( · , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 𝑚, ⦋(𝑓‘𝑛) / 𝑘⦌𝐵, 1)))‘𝑚) |
| 39 | 38 | nfeq2 2351 |
. . . . . . 7
⊢
Ⅎ𝑘 𝑥 = (seq1( · , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 𝑚, ⦋(𝑓‘𝑛) / 𝑘⦌𝐵, 1)))‘𝑚) |
| 40 | 31, 39 | nfan 1579 |
. . . . . 6
⊢
Ⅎ𝑘(𝑓:(1...𝑚)–1-1-onto→𝐴 ∧ 𝑥 = (seq1( · , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 𝑚, ⦋(𝑓‘𝑛) / 𝑘⦌𝐵, 1)))‘𝑚)) |
| 41 | 40 | nfex 1651 |
. . . . 5
⊢
Ⅎ𝑘∃𝑓(𝑓:(1...𝑚)–1-1-onto→𝐴 ∧ 𝑥 = (seq1( · , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 𝑚, ⦋(𝑓‘𝑛) / 𝑘⦌𝐵, 1)))‘𝑚)) |
| 42 | 28, 41 | nfrexw 2536 |
. . . 4
⊢
Ⅎ𝑘∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto→𝐴 ∧ 𝑥 = (seq1( · , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 𝑚, ⦋(𝑓‘𝑛) / 𝑘⦌𝐵, 1)))‘𝑚)) |
| 43 | 27, 42 | nfor 1588 |
. . 3
⊢
Ⅎ𝑘(∃𝑚 ∈ ℤ ((𝐴 ⊆ (ℤ≥‘𝑚) ∧ ∀𝑗 ∈
(ℤ≥‘𝑚)DECID 𝑗 ∈ 𝐴) ∧ (∃𝑛 ∈ (ℤ≥‘𝑚)∃𝑦(𝑦 # 0 ∧ seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦) ∧ seq𝑚( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑥)) ∨ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto→𝐴 ∧ 𝑥 = (seq1( · , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 𝑚, ⦋(𝑓‘𝑛) / 𝑘⦌𝐵, 1)))‘𝑚))) |
| 44 | 43 | nfiotaw 5223 |
. 2
⊢
Ⅎ𝑘(℩𝑥(∃𝑚 ∈ ℤ ((𝐴 ⊆ (ℤ≥‘𝑚) ∧ ∀𝑗 ∈
(ℤ≥‘𝑚)DECID 𝑗 ∈ 𝐴) ∧ (∃𝑛 ∈ (ℤ≥‘𝑚)∃𝑦(𝑦 # 0 ∧ seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦) ∧ seq𝑚( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑥)) ∨ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto→𝐴 ∧ 𝑥 = (seq1( · , (𝑛 ∈ ℕ ↦ if(𝑛 ≤ 𝑚, ⦋(𝑓‘𝑛) / 𝑘⦌𝐵, 1)))‘𝑚)))) |
| 45 | 1, 44 | nfcxfr 2336 |
1
⊢
Ⅎ𝑘∏𝑘 ∈ 𝐴 𝐵 |