| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | relxp 5702 | . . . . . . . . 9
⊢ Rel
({𝑗} × 𝐵) | 
| 2 | 1 | rgenw 3064 | . . . . . . . 8
⊢
∀𝑗 ∈
𝐴 Rel ({𝑗} × 𝐵) | 
| 3 |  | reliun 5825 | . . . . . . . 8
⊢ (Rel
∪ 𝑗 ∈ 𝐴 ({𝑗} × 𝐵) ↔ ∀𝑗 ∈ 𝐴 Rel ({𝑗} × 𝐵)) | 
| 4 | 2, 3 | mpbir 231 | . . . . . . 7
⊢ Rel
∪ 𝑗 ∈ 𝐴 ({𝑗} × 𝐵) | 
| 5 |  | relcnv 6121 | . . . . . . 7
⊢ Rel ◡∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷) | 
| 6 |  | ancom 460 | . . . . . . . . . . . 12
⊢ ((𝑥 = 𝑗 ∧ 𝑦 = 𝑘) ↔ (𝑦 = 𝑘 ∧ 𝑥 = 𝑗)) | 
| 7 |  | vex 3483 | . . . . . . . . . . . . 13
⊢ 𝑥 ∈ V | 
| 8 |  | vex 3483 | . . . . . . . . . . . . 13
⊢ 𝑦 ∈ V | 
| 9 | 7, 8 | opth 5480 | . . . . . . . . . . . 12
⊢
(〈𝑥, 𝑦〉 = 〈𝑗, 𝑘〉 ↔ (𝑥 = 𝑗 ∧ 𝑦 = 𝑘)) | 
| 10 | 8, 7 | opth 5480 | . . . . . . . . . . . 12
⊢
(〈𝑦, 𝑥〉 = 〈𝑘, 𝑗〉 ↔ (𝑦 = 𝑘 ∧ 𝑥 = 𝑗)) | 
| 11 | 6, 9, 10 | 3bitr4i 303 | . . . . . . . . . . 11
⊢
(〈𝑥, 𝑦〉 = 〈𝑗, 𝑘〉 ↔ 〈𝑦, 𝑥〉 = 〈𝑘, 𝑗〉) | 
| 12 | 11 | a1i 11 | . . . . . . . . . 10
⊢ (𝜑 → (〈𝑥, 𝑦〉 = 〈𝑗, 𝑘〉 ↔ 〈𝑦, 𝑥〉 = 〈𝑘, 𝑗〉)) | 
| 13 |  | fsumcom2.4 | . . . . . . . . . 10
⊢ (𝜑 → ((𝑗 ∈ 𝐴 ∧ 𝑘 ∈ 𝐵) ↔ (𝑘 ∈ 𝐶 ∧ 𝑗 ∈ 𝐷))) | 
| 14 | 12, 13 | anbi12d 632 | . . . . . . . . 9
⊢ (𝜑 → ((〈𝑥, 𝑦〉 = 〈𝑗, 𝑘〉 ∧ (𝑗 ∈ 𝐴 ∧ 𝑘 ∈ 𝐵)) ↔ (〈𝑦, 𝑥〉 = 〈𝑘, 𝑗〉 ∧ (𝑘 ∈ 𝐶 ∧ 𝑗 ∈ 𝐷)))) | 
| 15 | 14 | 2exbidv 1923 | . . . . . . . 8
⊢ (𝜑 → (∃𝑗∃𝑘(〈𝑥, 𝑦〉 = 〈𝑗, 𝑘〉 ∧ (𝑗 ∈ 𝐴 ∧ 𝑘 ∈ 𝐵)) ↔ ∃𝑗∃𝑘(〈𝑦, 𝑥〉 = 〈𝑘, 𝑗〉 ∧ (𝑘 ∈ 𝐶 ∧ 𝑗 ∈ 𝐷)))) | 
| 16 |  | eliunxp 5847 | . . . . . . . 8
⊢
(〈𝑥, 𝑦〉 ∈ ∪ 𝑗 ∈ 𝐴 ({𝑗} × 𝐵) ↔ ∃𝑗∃𝑘(〈𝑥, 𝑦〉 = 〈𝑗, 𝑘〉 ∧ (𝑗 ∈ 𝐴 ∧ 𝑘 ∈ 𝐵))) | 
| 17 | 7, 8 | opelcnv 5891 | . . . . . . . . 9
⊢
(〈𝑥, 𝑦〉 ∈ ◡∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷) ↔ 〈𝑦, 𝑥〉 ∈ ∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷)) | 
| 18 |  | eliunxp 5847 | . . . . . . . . 9
⊢
(〈𝑦, 𝑥〉 ∈ ∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷) ↔ ∃𝑘∃𝑗(〈𝑦, 𝑥〉 = 〈𝑘, 𝑗〉 ∧ (𝑘 ∈ 𝐶 ∧ 𝑗 ∈ 𝐷))) | 
| 19 |  | excom 2161 | . . . . . . . . 9
⊢
(∃𝑘∃𝑗(〈𝑦, 𝑥〉 = 〈𝑘, 𝑗〉 ∧ (𝑘 ∈ 𝐶 ∧ 𝑗 ∈ 𝐷)) ↔ ∃𝑗∃𝑘(〈𝑦, 𝑥〉 = 〈𝑘, 𝑗〉 ∧ (𝑘 ∈ 𝐶 ∧ 𝑗 ∈ 𝐷))) | 
| 20 | 17, 18, 19 | 3bitri 297 | . . . . . . . 8
⊢
(〈𝑥, 𝑦〉 ∈ ◡∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷) ↔ ∃𝑗∃𝑘(〈𝑦, 𝑥〉 = 〈𝑘, 𝑗〉 ∧ (𝑘 ∈ 𝐶 ∧ 𝑗 ∈ 𝐷))) | 
| 21 | 15, 16, 20 | 3bitr4g 314 | . . . . . . 7
⊢ (𝜑 → (〈𝑥, 𝑦〉 ∈ ∪ 𝑗 ∈ 𝐴 ({𝑗} × 𝐵) ↔ 〈𝑥, 𝑦〉 ∈ ◡∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷))) | 
| 22 | 4, 5, 21 | eqrelrdv 5801 | . . . . . 6
⊢ (𝜑 → ∪ 𝑗 ∈ 𝐴 ({𝑗} × 𝐵) = ◡∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷)) | 
| 23 |  | nfcv 2904 | . . . . . . 7
⊢
Ⅎ𝑚({𝑗} × 𝐵) | 
| 24 |  | nfcv 2904 | . . . . . . . 8
⊢
Ⅎ𝑗{𝑚} | 
| 25 |  | nfcsb1v 3922 | . . . . . . . 8
⊢
Ⅎ𝑗⦋𝑚 / 𝑗⦌𝐵 | 
| 26 | 24, 25 | nfxp 5717 | . . . . . . 7
⊢
Ⅎ𝑗({𝑚} × ⦋𝑚 / 𝑗⦌𝐵) | 
| 27 |  | sneq 4635 | . . . . . . . 8
⊢ (𝑗 = 𝑚 → {𝑗} = {𝑚}) | 
| 28 |  | csbeq1a 3912 | . . . . . . . 8
⊢ (𝑗 = 𝑚 → 𝐵 = ⦋𝑚 / 𝑗⦌𝐵) | 
| 29 | 27, 28 | xpeq12d 5715 | . . . . . . 7
⊢ (𝑗 = 𝑚 → ({𝑗} × 𝐵) = ({𝑚} × ⦋𝑚 / 𝑗⦌𝐵)) | 
| 30 | 23, 26, 29 | cbviun 5035 | . . . . . 6
⊢ ∪ 𝑗 ∈ 𝐴 ({𝑗} × 𝐵) = ∪
𝑚 ∈ 𝐴 ({𝑚} × ⦋𝑚 / 𝑗⦌𝐵) | 
| 31 |  | nfcv 2904 | . . . . . . . 8
⊢
Ⅎ𝑛({𝑘} × 𝐷) | 
| 32 |  | nfcv 2904 | . . . . . . . . 9
⊢
Ⅎ𝑘{𝑛} | 
| 33 |  | nfcsb1v 3922 | . . . . . . . . 9
⊢
Ⅎ𝑘⦋𝑛 / 𝑘⦌𝐷 | 
| 34 | 32, 33 | nfxp 5717 | . . . . . . . 8
⊢
Ⅎ𝑘({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) | 
| 35 |  | sneq 4635 | . . . . . . . . 9
⊢ (𝑘 = 𝑛 → {𝑘} = {𝑛}) | 
| 36 |  | csbeq1a 3912 | . . . . . . . . 9
⊢ (𝑘 = 𝑛 → 𝐷 = ⦋𝑛 / 𝑘⦌𝐷) | 
| 37 | 35, 36 | xpeq12d 5715 | . . . . . . . 8
⊢ (𝑘 = 𝑛 → ({𝑘} × 𝐷) = ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) | 
| 38 | 31, 34, 37 | cbviun 5035 | . . . . . . 7
⊢ ∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷) = ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) | 
| 39 | 38 | cnveqi 5884 | . . . . . 6
⊢ ◡∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷) = ◡∪ 𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) | 
| 40 | 22, 30, 39 | 3eqtr3g 2799 | . . . . 5
⊢ (𝜑 → ∪ 𝑚 ∈ 𝐴 ({𝑚} × ⦋𝑚 / 𝑗⦌𝐵) = ◡∪ 𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) | 
| 41 | 40 | sumeq1d 15737 | . . . 4
⊢ (𝜑 → Σ𝑧 ∈ ∪
𝑚 ∈ 𝐴 ({𝑚} × ⦋𝑚 / 𝑗⦌𝐵)⦋(2nd ‘𝑧) / 𝑘⦌⦋(1st
‘𝑧) / 𝑗⦌𝐸 = Σ𝑧 ∈ ◡ ∪ 𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)⦋(2nd ‘𝑧) / 𝑘⦌⦋(1st
‘𝑧) / 𝑗⦌𝐸) | 
| 42 |  | vex 3483 | . . . . . . . 8
⊢ 𝑛 ∈ V | 
| 43 |  | vex 3483 | . . . . . . . 8
⊢ 𝑚 ∈ V | 
| 44 | 42, 43 | op1std 8025 | . . . . . . 7
⊢ (𝑤 = 〈𝑛, 𝑚〉 → (1st ‘𝑤) = 𝑛) | 
| 45 | 44 | csbeq1d 3902 | . . . . . 6
⊢ (𝑤 = 〈𝑛, 𝑚〉 → ⦋(1st
‘𝑤) / 𝑘⦌⦋(2nd
‘𝑤) / 𝑗⦌𝐸 = ⦋𝑛 / 𝑘⦌⦋(2nd
‘𝑤) / 𝑗⦌𝐸) | 
| 46 | 42, 43 | op2ndd 8026 | . . . . . . . 8
⊢ (𝑤 = 〈𝑛, 𝑚〉 → (2nd ‘𝑤) = 𝑚) | 
| 47 | 46 | csbeq1d 3902 | . . . . . . 7
⊢ (𝑤 = 〈𝑛, 𝑚〉 → ⦋(2nd
‘𝑤) / 𝑗⦌𝐸 = ⦋𝑚 / 𝑗⦌𝐸) | 
| 48 | 47 | csbeq2dv 3905 | . . . . . 6
⊢ (𝑤 = 〈𝑛, 𝑚〉 → ⦋𝑛 / 𝑘⦌⦋(2nd
‘𝑤) / 𝑗⦌𝐸 = ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 49 | 45, 48 | eqtrd 2776 | . . . . 5
⊢ (𝑤 = 〈𝑛, 𝑚〉 → ⦋(1st
‘𝑤) / 𝑘⦌⦋(2nd
‘𝑤) / 𝑗⦌𝐸 = ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 50 | 43, 42 | op2ndd 8026 | . . . . . . 7
⊢ (𝑧 = 〈𝑚, 𝑛〉 → (2nd ‘𝑧) = 𝑛) | 
| 51 | 50 | csbeq1d 3902 | . . . . . 6
⊢ (𝑧 = 〈𝑚, 𝑛〉 → ⦋(2nd
‘𝑧) / 𝑘⦌⦋(1st
‘𝑧) / 𝑗⦌𝐸 = ⦋𝑛 / 𝑘⦌⦋(1st
‘𝑧) / 𝑗⦌𝐸) | 
| 52 | 43, 42 | op1std 8025 | . . . . . . . 8
⊢ (𝑧 = 〈𝑚, 𝑛〉 → (1st ‘𝑧) = 𝑚) | 
| 53 | 52 | csbeq1d 3902 | . . . . . . 7
⊢ (𝑧 = 〈𝑚, 𝑛〉 → ⦋(1st
‘𝑧) / 𝑗⦌𝐸 = ⦋𝑚 / 𝑗⦌𝐸) | 
| 54 | 53 | csbeq2dv 3905 | . . . . . 6
⊢ (𝑧 = 〈𝑚, 𝑛〉 → ⦋𝑛 / 𝑘⦌⦋(1st
‘𝑧) / 𝑗⦌𝐸 = ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 55 | 51, 54 | eqtrd 2776 | . . . . 5
⊢ (𝑧 = 〈𝑚, 𝑛〉 → ⦋(2nd
‘𝑧) / 𝑘⦌⦋(1st
‘𝑧) / 𝑗⦌𝐸 = ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 56 |  | fsumcom2.2 | . . . . . 6
⊢ (𝜑 → 𝐶 ∈ Fin) | 
| 57 |  | snfi 9084 | . . . . . . . 8
⊢ {𝑛} ∈ Fin | 
| 58 |  | fsumcom2.1 | . . . . . . . . . 10
⊢ (𝜑 → 𝐴 ∈ Fin) | 
| 59 | 58 | adantr 480 | . . . . . . . . 9
⊢ ((𝜑 ∧ 𝑛 ∈ 𝐶) → 𝐴 ∈ Fin) | 
| 60 | 43, 42 | opelcnv 5891 | . . . . . . . . . . . . . . . 16
⊢
(〈𝑚, 𝑛〉 ∈ ◡∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷) ↔ 〈𝑛, 𝑚〉 ∈ ∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷)) | 
| 61 | 33, 36 | opeliunxp2f 8236 | . . . . . . . . . . . . . . . 16
⊢
(〈𝑛, 𝑚〉 ∈ ∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷) ↔ (𝑛 ∈ 𝐶 ∧ 𝑚 ∈ ⦋𝑛 / 𝑘⦌𝐷)) | 
| 62 | 60, 61 | sylbbr 236 | . . . . . . . . . . . . . . 15
⊢ ((𝑛 ∈ 𝐶 ∧ 𝑚 ∈ ⦋𝑛 / 𝑘⦌𝐷) → 〈𝑚, 𝑛〉 ∈ ◡∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷)) | 
| 63 | 62 | adantl 481 | . . . . . . . . . . . . . 14
⊢ ((𝜑 ∧ (𝑛 ∈ 𝐶 ∧ 𝑚 ∈ ⦋𝑛 / 𝑘⦌𝐷)) → 〈𝑚, 𝑛〉 ∈ ◡∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷)) | 
| 64 | 22 | adantr 480 | . . . . . . . . . . . . . 14
⊢ ((𝜑 ∧ (𝑛 ∈ 𝐶 ∧ 𝑚 ∈ ⦋𝑛 / 𝑘⦌𝐷)) → ∪ 𝑗 ∈ 𝐴 ({𝑗} × 𝐵) = ◡∪ 𝑘 ∈ 𝐶 ({𝑘} × 𝐷)) | 
| 65 | 63, 64 | eleqtrrd 2843 | . . . . . . . . . . . . 13
⊢ ((𝜑 ∧ (𝑛 ∈ 𝐶 ∧ 𝑚 ∈ ⦋𝑛 / 𝑘⦌𝐷)) → 〈𝑚, 𝑛〉 ∈ ∪ 𝑗 ∈ 𝐴 ({𝑗} × 𝐵)) | 
| 66 |  | eliun 4994 | . . . . . . . . . . . . 13
⊢
(〈𝑚, 𝑛〉 ∈ ∪ 𝑗 ∈ 𝐴 ({𝑗} × 𝐵) ↔ ∃𝑗 ∈ 𝐴 〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵)) | 
| 67 | 65, 66 | sylib 218 | . . . . . . . . . . . 12
⊢ ((𝜑 ∧ (𝑛 ∈ 𝐶 ∧ 𝑚 ∈ ⦋𝑛 / 𝑘⦌𝐷)) → ∃𝑗 ∈ 𝐴 〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵)) | 
| 68 |  | simpr 484 | . . . . . . . . . . . . . . . . 17
⊢ ((𝑗 ∈ 𝐴 ∧ 〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵)) → 〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵)) | 
| 69 |  | opelxp 5720 | . . . . . . . . . . . . . . . . 17
⊢
(〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵) ↔ (𝑚 ∈ {𝑗} ∧ 𝑛 ∈ 𝐵)) | 
| 70 | 68, 69 | sylib 218 | . . . . . . . . . . . . . . . 16
⊢ ((𝑗 ∈ 𝐴 ∧ 〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵)) → (𝑚 ∈ {𝑗} ∧ 𝑛 ∈ 𝐵)) | 
| 71 | 70 | simpld 494 | . . . . . . . . . . . . . . 15
⊢ ((𝑗 ∈ 𝐴 ∧ 〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵)) → 𝑚 ∈ {𝑗}) | 
| 72 |  | elsni 4642 | . . . . . . . . . . . . . . 15
⊢ (𝑚 ∈ {𝑗} → 𝑚 = 𝑗) | 
| 73 | 71, 72 | syl 17 | . . . . . . . . . . . . . 14
⊢ ((𝑗 ∈ 𝐴 ∧ 〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵)) → 𝑚 = 𝑗) | 
| 74 |  | simpl 482 | . . . . . . . . . . . . . 14
⊢ ((𝑗 ∈ 𝐴 ∧ 〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵)) → 𝑗 ∈ 𝐴) | 
| 75 | 73, 74 | eqeltrd 2840 | . . . . . . . . . . . . 13
⊢ ((𝑗 ∈ 𝐴 ∧ 〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵)) → 𝑚 ∈ 𝐴) | 
| 76 | 75 | rexlimiva 3146 | . . . . . . . . . . . 12
⊢
(∃𝑗 ∈
𝐴 〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵) → 𝑚 ∈ 𝐴) | 
| 77 | 67, 76 | syl 17 | . . . . . . . . . . 11
⊢ ((𝜑 ∧ (𝑛 ∈ 𝐶 ∧ 𝑚 ∈ ⦋𝑛 / 𝑘⦌𝐷)) → 𝑚 ∈ 𝐴) | 
| 78 | 77 | expr 456 | . . . . . . . . . 10
⊢ ((𝜑 ∧ 𝑛 ∈ 𝐶) → (𝑚 ∈ ⦋𝑛 / 𝑘⦌𝐷 → 𝑚 ∈ 𝐴)) | 
| 79 | 78 | ssrdv 3988 | . . . . . . . . 9
⊢ ((𝜑 ∧ 𝑛 ∈ 𝐶) → ⦋𝑛 / 𝑘⦌𝐷 ⊆ 𝐴) | 
| 80 | 59, 79 | ssfid 9302 | . . . . . . . 8
⊢ ((𝜑 ∧ 𝑛 ∈ 𝐶) → ⦋𝑛 / 𝑘⦌𝐷 ∈ Fin) | 
| 81 |  | xpfi 9359 | . . . . . . . 8
⊢ (({𝑛} ∈ Fin ∧
⦋𝑛 / 𝑘⦌𝐷 ∈ Fin) → ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) ∈ Fin) | 
| 82 | 57, 80, 81 | sylancr 587 | . . . . . . 7
⊢ ((𝜑 ∧ 𝑛 ∈ 𝐶) → ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) ∈ Fin) | 
| 83 | 82 | ralrimiva 3145 | . . . . . 6
⊢ (𝜑 → ∀𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) ∈ Fin) | 
| 84 |  | iunfi 9384 | . . . . . 6
⊢ ((𝐶 ∈ Fin ∧ ∀𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) ∈ Fin) → ∪ 𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) ∈ Fin) | 
| 85 | 56, 83, 84 | syl2anc 584 | . . . . 5
⊢ (𝜑 → ∪ 𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) ∈ Fin) | 
| 86 |  | reliun 5825 | . . . . . . 7
⊢ (Rel
∪ 𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) ↔ ∀𝑛 ∈ 𝐶 Rel ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) | 
| 87 |  | relxp 5702 | . . . . . . . 8
⊢ Rel
({𝑛} ×
⦋𝑛 / 𝑘⦌𝐷) | 
| 88 | 87 | a1i 11 | . . . . . . 7
⊢ (𝑛 ∈ 𝐶 → Rel ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) | 
| 89 | 86, 88 | mprgbir 3067 | . . . . . 6
⊢ Rel
∪ 𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) | 
| 90 | 89 | a1i 11 | . . . . 5
⊢ (𝜑 → Rel ∪ 𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) | 
| 91 |  | csbeq1 3901 | . . . . . . . 8
⊢ (𝑚 = (2nd ‘𝑤) → ⦋𝑚 / 𝑗⦌𝐸 = ⦋(2nd
‘𝑤) / 𝑗⦌𝐸) | 
| 92 | 91 | csbeq2dv 3905 | . . . . . . 7
⊢ (𝑚 = (2nd ‘𝑤) →
⦋(1st ‘𝑤) / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 = ⦋(1st
‘𝑤) / 𝑘⦌⦋(2nd
‘𝑤) / 𝑗⦌𝐸) | 
| 93 | 92 | eleq1d 2825 | . . . . . 6
⊢ (𝑚 = (2nd ‘𝑤) →
(⦋(1st ‘𝑤) / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ ↔
⦋(1st ‘𝑤) / 𝑘⦌⦋(2nd
‘𝑤) / 𝑗⦌𝐸 ∈ ℂ)) | 
| 94 |  | csbeq1 3901 | . . . . . . . 8
⊢ (𝑛 = (1st ‘𝑤) → ⦋𝑛 / 𝑘⦌𝐷 = ⦋(1st
‘𝑤) / 𝑘⦌𝐷) | 
| 95 |  | csbeq1 3901 | . . . . . . . . 9
⊢ (𝑛 = (1st ‘𝑤) → ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 = ⦋(1st
‘𝑤) / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 96 | 95 | eleq1d 2825 | . . . . . . . 8
⊢ (𝑛 = (1st ‘𝑤) → (⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ ↔
⦋(1st ‘𝑤) / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ)) | 
| 97 | 94, 96 | raleqbidv 3345 | . . . . . . 7
⊢ (𝑛 = (1st ‘𝑤) → (∀𝑚 ∈ ⦋ 𝑛 / 𝑘⦌𝐷⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ ↔ ∀𝑚 ∈ ⦋
(1st ‘𝑤) /
𝑘⦌𝐷⦋(1st
‘𝑤) / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ)) | 
| 98 |  | simpl 482 | . . . . . . . . . 10
⊢ ((𝜑 ∧ (𝑛 ∈ 𝐶 ∧ 𝑚 ∈ ⦋𝑛 / 𝑘⦌𝐷)) → 𝜑) | 
| 99 | 25 | nfcri 2896 | . . . . . . . . . . . 12
⊢
Ⅎ𝑗 𝑛 ∈ ⦋𝑚 / 𝑗⦌𝐵 | 
| 100 | 72 | equcomd 2017 | . . . . . . . . . . . . . . . . 17
⊢ (𝑚 ∈ {𝑗} → 𝑗 = 𝑚) | 
| 101 | 100, 28 | syl 17 | . . . . . . . . . . . . . . . 16
⊢ (𝑚 ∈ {𝑗} → 𝐵 = ⦋𝑚 / 𝑗⦌𝐵) | 
| 102 | 101 | eleq2d 2826 | . . . . . . . . . . . . . . 15
⊢ (𝑚 ∈ {𝑗} → (𝑛 ∈ 𝐵 ↔ 𝑛 ∈ ⦋𝑚 / 𝑗⦌𝐵)) | 
| 103 | 102 | biimpa 476 | . . . . . . . . . . . . . 14
⊢ ((𝑚 ∈ {𝑗} ∧ 𝑛 ∈ 𝐵) → 𝑛 ∈ ⦋𝑚 / 𝑗⦌𝐵) | 
| 104 | 69, 103 | sylbi 217 | . . . . . . . . . . . . 13
⊢
(〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵) → 𝑛 ∈ ⦋𝑚 / 𝑗⦌𝐵) | 
| 105 | 104 | a1i 11 | . . . . . . . . . . . 12
⊢ (𝑗 ∈ 𝐴 → (〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵) → 𝑛 ∈ ⦋𝑚 / 𝑗⦌𝐵)) | 
| 106 | 99, 105 | rexlimi 3258 | . . . . . . . . . . 11
⊢
(∃𝑗 ∈
𝐴 〈𝑚, 𝑛〉 ∈ ({𝑗} × 𝐵) → 𝑛 ∈ ⦋𝑚 / 𝑗⦌𝐵) | 
| 107 | 67, 106 | syl 17 | . . . . . . . . . 10
⊢ ((𝜑 ∧ (𝑛 ∈ 𝐶 ∧ 𝑚 ∈ ⦋𝑛 / 𝑘⦌𝐷)) → 𝑛 ∈ ⦋𝑚 / 𝑗⦌𝐵) | 
| 108 |  | fsumcom2.5 | . . . . . . . . . . . . . 14
⊢ ((𝜑 ∧ (𝑗 ∈ 𝐴 ∧ 𝑘 ∈ 𝐵)) → 𝐸 ∈ ℂ) | 
| 109 | 108 | ralrimivva 3201 | . . . . . . . . . . . . 13
⊢ (𝜑 → ∀𝑗 ∈ 𝐴 ∀𝑘 ∈ 𝐵 𝐸 ∈ ℂ) | 
| 110 |  | nfcsb1v 3922 | . . . . . . . . . . . . . . . 16
⊢
Ⅎ𝑗⦋𝑚 / 𝑗⦌𝐸 | 
| 111 | 110 | nfel1 2921 | . . . . . . . . . . . . . . 15
⊢
Ⅎ𝑗⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ | 
| 112 | 25, 111 | nfralw 3310 | . . . . . . . . . . . . . 14
⊢
Ⅎ𝑗∀𝑘 ∈ ⦋ 𝑚 / 𝑗⦌𝐵⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ | 
| 113 |  | csbeq1a 3912 | . . . . . . . . . . . . . . . 16
⊢ (𝑗 = 𝑚 → 𝐸 = ⦋𝑚 / 𝑗⦌𝐸) | 
| 114 | 113 | eleq1d 2825 | . . . . . . . . . . . . . . 15
⊢ (𝑗 = 𝑚 → (𝐸 ∈ ℂ ↔ ⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ)) | 
| 115 | 28, 114 | raleqbidv 3345 | . . . . . . . . . . . . . 14
⊢ (𝑗 = 𝑚 → (∀𝑘 ∈ 𝐵 𝐸 ∈ ℂ ↔ ∀𝑘 ∈ ⦋ 𝑚 / 𝑗⦌𝐵⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ)) | 
| 116 | 112, 115 | rspc 3609 | . . . . . . . . . . . . 13
⊢ (𝑚 ∈ 𝐴 → (∀𝑗 ∈ 𝐴 ∀𝑘 ∈ 𝐵 𝐸 ∈ ℂ → ∀𝑘 ∈ ⦋ 𝑚 / 𝑗⦌𝐵⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ)) | 
| 117 | 109, 116 | mpan9 506 | . . . . . . . . . . . 12
⊢ ((𝜑 ∧ 𝑚 ∈ 𝐴) → ∀𝑘 ∈ ⦋ 𝑚 / 𝑗⦌𝐵⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ) | 
| 118 |  | nfcsb1v 3922 | . . . . . . . . . . . . . 14
⊢
Ⅎ𝑘⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 | 
| 119 | 118 | nfel1 2921 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑘⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ | 
| 120 |  | csbeq1a 3912 | . . . . . . . . . . . . . 14
⊢ (𝑘 = 𝑛 → ⦋𝑚 / 𝑗⦌𝐸 = ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 121 | 120 | eleq1d 2825 | . . . . . . . . . . . . 13
⊢ (𝑘 = 𝑛 → (⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ ↔ ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ)) | 
| 122 | 119, 121 | rspc 3609 | . . . . . . . . . . . 12
⊢ (𝑛 ∈ ⦋𝑚 / 𝑗⦌𝐵 → (∀𝑘 ∈ ⦋ 𝑚 / 𝑗⦌𝐵⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ → ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ)) | 
| 123 | 117, 122 | syl5com 31 | . . . . . . . . . . 11
⊢ ((𝜑 ∧ 𝑚 ∈ 𝐴) → (𝑛 ∈ ⦋𝑚 / 𝑗⦌𝐵 → ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ)) | 
| 124 | 123 | impr 454 | . . . . . . . . . 10
⊢ ((𝜑 ∧ (𝑚 ∈ 𝐴 ∧ 𝑛 ∈ ⦋𝑚 / 𝑗⦌𝐵)) → ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ) | 
| 125 | 98, 77, 107, 124 | syl12anc 836 | . . . . . . . . 9
⊢ ((𝜑 ∧ (𝑛 ∈ 𝐶 ∧ 𝑚 ∈ ⦋𝑛 / 𝑘⦌𝐷)) → ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ) | 
| 126 | 125 | ralrimivva 3201 | . . . . . . . 8
⊢ (𝜑 → ∀𝑛 ∈ 𝐶 ∀𝑚 ∈ ⦋ 𝑛 / 𝑘⦌𝐷⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ) | 
| 127 | 126 | adantr 480 | . . . . . . 7
⊢ ((𝜑 ∧ 𝑤 ∈ ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → ∀𝑛 ∈ 𝐶 ∀𝑚 ∈ ⦋ 𝑛 / 𝑘⦌𝐷⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ) | 
| 128 |  | simpr 484 | . . . . . . . . 9
⊢ ((𝜑 ∧ 𝑤 ∈ ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → 𝑤 ∈ ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) | 
| 129 |  | eliun 4994 | . . . . . . . . 9
⊢ (𝑤 ∈ ∪ 𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) ↔ ∃𝑛 ∈ 𝐶 𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) | 
| 130 | 128, 129 | sylib 218 | . . . . . . . 8
⊢ ((𝜑 ∧ 𝑤 ∈ ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → ∃𝑛 ∈ 𝐶 𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) | 
| 131 |  | xp1st 8047 | . . . . . . . . . . . 12
⊢ (𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) → (1st ‘𝑤) ∈ {𝑛}) | 
| 132 | 131 | adantl 481 | . . . . . . . . . . 11
⊢ ((𝑛 ∈ 𝐶 ∧ 𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → (1st ‘𝑤) ∈ {𝑛}) | 
| 133 |  | elsni 4642 | . . . . . . . . . . 11
⊢
((1st ‘𝑤) ∈ {𝑛} → (1st ‘𝑤) = 𝑛) | 
| 134 | 132, 133 | syl 17 | . . . . . . . . . 10
⊢ ((𝑛 ∈ 𝐶 ∧ 𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → (1st ‘𝑤) = 𝑛) | 
| 135 |  | simpl 482 | . . . . . . . . . 10
⊢ ((𝑛 ∈ 𝐶 ∧ 𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → 𝑛 ∈ 𝐶) | 
| 136 | 134, 135 | eqeltrd 2840 | . . . . . . . . 9
⊢ ((𝑛 ∈ 𝐶 ∧ 𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → (1st ‘𝑤) ∈ 𝐶) | 
| 137 | 136 | rexlimiva 3146 | . . . . . . . 8
⊢
(∃𝑛 ∈
𝐶 𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) → (1st ‘𝑤) ∈ 𝐶) | 
| 138 | 130, 137 | syl 17 | . . . . . . 7
⊢ ((𝜑 ∧ 𝑤 ∈ ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → (1st ‘𝑤) ∈ 𝐶) | 
| 139 | 97, 127, 138 | rspcdva 3622 | . . . . . 6
⊢ ((𝜑 ∧ 𝑤 ∈ ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → ∀𝑚 ∈ ⦋ (1st
‘𝑤) / 𝑘⦌𝐷⦋(1st ‘𝑤) / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 ∈ ℂ) | 
| 140 |  | xp2nd 8048 | . . . . . . . . . 10
⊢ (𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) → (2nd ‘𝑤) ∈ ⦋𝑛 / 𝑘⦌𝐷) | 
| 141 | 140 | adantl 481 | . . . . . . . . 9
⊢ ((𝑛 ∈ 𝐶 ∧ 𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → (2nd ‘𝑤) ∈ ⦋𝑛 / 𝑘⦌𝐷) | 
| 142 | 134 | csbeq1d 3902 | . . . . . . . . 9
⊢ ((𝑛 ∈ 𝐶 ∧ 𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → ⦋(1st
‘𝑤) / 𝑘⦌𝐷 = ⦋𝑛 / 𝑘⦌𝐷) | 
| 143 | 141, 142 | eleqtrrd 2843 | . . . . . . . 8
⊢ ((𝑛 ∈ 𝐶 ∧ 𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → (2nd ‘𝑤) ∈
⦋(1st ‘𝑤) / 𝑘⦌𝐷) | 
| 144 | 143 | rexlimiva 3146 | . . . . . . 7
⊢
(∃𝑛 ∈
𝐶 𝑤 ∈ ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷) → (2nd ‘𝑤) ∈
⦋(1st ‘𝑤) / 𝑘⦌𝐷) | 
| 145 | 130, 144 | syl 17 | . . . . . 6
⊢ ((𝜑 ∧ 𝑤 ∈ ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → (2nd ‘𝑤) ∈
⦋(1st ‘𝑤) / 𝑘⦌𝐷) | 
| 146 | 93, 139, 145 | rspcdva 3622 | . . . . 5
⊢ ((𝜑 ∧ 𝑤 ∈ ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)) → ⦋(1st
‘𝑤) / 𝑘⦌⦋(2nd
‘𝑤) / 𝑗⦌𝐸 ∈ ℂ) | 
| 147 | 49, 55, 85, 90, 146 | fsumcnv 15810 | . . . 4
⊢ (𝜑 → Σ𝑤 ∈ ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)⦋(1st ‘𝑤) / 𝑘⦌⦋(2nd
‘𝑤) / 𝑗⦌𝐸 = Σ𝑧 ∈ ◡ ∪ 𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)⦋(2nd ‘𝑧) / 𝑘⦌⦋(1st
‘𝑧) / 𝑗⦌𝐸) | 
| 148 | 41, 147 | eqtr4d 2779 | . . 3
⊢ (𝜑 → Σ𝑧 ∈ ∪
𝑚 ∈ 𝐴 ({𝑚} × ⦋𝑚 / 𝑗⦌𝐵)⦋(2nd ‘𝑧) / 𝑘⦌⦋(1st
‘𝑧) / 𝑗⦌𝐸 = Σ𝑤 ∈ ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)⦋(1st ‘𝑤) / 𝑘⦌⦋(2nd
‘𝑤) / 𝑗⦌𝐸) | 
| 149 |  | fsumcom2.3 | . . . . . 6
⊢ ((𝜑 ∧ 𝑗 ∈ 𝐴) → 𝐵 ∈ Fin) | 
| 150 | 149 | ralrimiva 3145 | . . . . 5
⊢ (𝜑 → ∀𝑗 ∈ 𝐴 𝐵 ∈ Fin) | 
| 151 | 25 | nfel1 2921 | . . . . . 6
⊢
Ⅎ𝑗⦋𝑚 / 𝑗⦌𝐵 ∈ Fin | 
| 152 | 28 | eleq1d 2825 | . . . . . 6
⊢ (𝑗 = 𝑚 → (𝐵 ∈ Fin ↔ ⦋𝑚 / 𝑗⦌𝐵 ∈ Fin)) | 
| 153 | 151, 152 | rspc 3609 | . . . . 5
⊢ (𝑚 ∈ 𝐴 → (∀𝑗 ∈ 𝐴 𝐵 ∈ Fin → ⦋𝑚 / 𝑗⦌𝐵 ∈ Fin)) | 
| 154 | 150, 153 | mpan9 506 | . . . 4
⊢ ((𝜑 ∧ 𝑚 ∈ 𝐴) → ⦋𝑚 / 𝑗⦌𝐵 ∈ Fin) | 
| 155 | 55, 58, 154, 124 | fsum2d 15808 | . . 3
⊢ (𝜑 → Σ𝑚 ∈ 𝐴 Σ𝑛 ∈ ⦋ 𝑚 / 𝑗⦌𝐵⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 = Σ𝑧 ∈ ∪
𝑚 ∈ 𝐴 ({𝑚} × ⦋𝑚 / 𝑗⦌𝐵)⦋(2nd ‘𝑧) / 𝑘⦌⦋(1st
‘𝑧) / 𝑗⦌𝐸) | 
| 156 | 49, 56, 80, 125 | fsum2d 15808 | . . 3
⊢ (𝜑 → Σ𝑛 ∈ 𝐶 Σ𝑚 ∈ ⦋ 𝑛 / 𝑘⦌𝐷⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 = Σ𝑤 ∈ ∪
𝑛 ∈ 𝐶 ({𝑛} × ⦋𝑛 / 𝑘⦌𝐷)⦋(1st ‘𝑤) / 𝑘⦌⦋(2nd
‘𝑤) / 𝑗⦌𝐸) | 
| 157 | 148, 155,
156 | 3eqtr4d 2786 | . 2
⊢ (𝜑 → Σ𝑚 ∈ 𝐴 Σ𝑛 ∈ ⦋ 𝑚 / 𝑗⦌𝐵⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 = Σ𝑛 ∈ 𝐶 Σ𝑚 ∈ ⦋ 𝑛 / 𝑘⦌𝐷⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 158 |  | csbeq1a 3912 | . . . . 5
⊢ (𝑘 = 𝑛 → 𝐸 = ⦋𝑛 / 𝑘⦌𝐸) | 
| 159 |  | nfcv 2904 | . . . . 5
⊢
Ⅎ𝑛𝐸 | 
| 160 |  | nfcsb1v 3922 | . . . . 5
⊢
Ⅎ𝑘⦋𝑛 / 𝑘⦌𝐸 | 
| 161 | 158, 159,
160 | cbvsum 15732 | . . . 4
⊢
Σ𝑘 ∈
𝐵 𝐸 = Σ𝑛 ∈ 𝐵 ⦋𝑛 / 𝑘⦌𝐸 | 
| 162 | 113 | csbeq2dv 3905 | . . . . . 6
⊢ (𝑗 = 𝑚 → ⦋𝑛 / 𝑘⦌𝐸 = ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 163 | 162 | adantr 480 | . . . . 5
⊢ ((𝑗 = 𝑚 ∧ 𝑛 ∈ 𝐵) → ⦋𝑛 / 𝑘⦌𝐸 = ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 164 | 28, 163 | sumeq12dv 15743 | . . . 4
⊢ (𝑗 = 𝑚 → Σ𝑛 ∈ 𝐵 ⦋𝑛 / 𝑘⦌𝐸 = Σ𝑛 ∈ ⦋ 𝑚 / 𝑗⦌𝐵⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 165 | 161, 164 | eqtrid 2788 | . . 3
⊢ (𝑗 = 𝑚 → Σ𝑘 ∈ 𝐵 𝐸 = Σ𝑛 ∈ ⦋ 𝑚 / 𝑗⦌𝐵⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 166 |  | nfcv 2904 | . . 3
⊢
Ⅎ𝑚Σ𝑘 ∈ 𝐵 𝐸 | 
| 167 |  | nfcv 2904 | . . . . 5
⊢
Ⅎ𝑗𝑛 | 
| 168 | 167, 110 | nfcsbw 3924 | . . . 4
⊢
Ⅎ𝑗⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 | 
| 169 | 25, 168 | nfsum 15728 | . . 3
⊢
Ⅎ𝑗Σ𝑛 ∈ ⦋ 𝑚 / 𝑗⦌𝐵⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 | 
| 170 | 165, 166,
169 | cbvsum 15732 | . 2
⊢
Σ𝑗 ∈
𝐴 Σ𝑘 ∈ 𝐵 𝐸 = Σ𝑚 ∈ 𝐴 Σ𝑛 ∈ ⦋ 𝑚 / 𝑗⦌𝐵⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 | 
| 171 |  | nfcv 2904 | . . . . 5
⊢
Ⅎ𝑚𝐸 | 
| 172 | 113, 171,
110 | cbvsum 15732 | . . . 4
⊢
Σ𝑗 ∈
𝐷 𝐸 = Σ𝑚 ∈ 𝐷 ⦋𝑚 / 𝑗⦌𝐸 | 
| 173 | 120 | adantr 480 | . . . . 5
⊢ ((𝑘 = 𝑛 ∧ 𝑚 ∈ 𝐷) → ⦋𝑚 / 𝑗⦌𝐸 = ⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 174 | 36, 173 | sumeq12dv 15743 | . . . 4
⊢ (𝑘 = 𝑛 → Σ𝑚 ∈ 𝐷 ⦋𝑚 / 𝑗⦌𝐸 = Σ𝑚 ∈ ⦋ 𝑛 / 𝑘⦌𝐷⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 175 | 172, 174 | eqtrid 2788 | . . 3
⊢ (𝑘 = 𝑛 → Σ𝑗 ∈ 𝐷 𝐸 = Σ𝑚 ∈ ⦋ 𝑛 / 𝑘⦌𝐷⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸) | 
| 176 |  | nfcv 2904 | . . 3
⊢
Ⅎ𝑛Σ𝑗 ∈ 𝐷 𝐸 | 
| 177 | 33, 118 | nfsum 15728 | . . 3
⊢
Ⅎ𝑘Σ𝑚 ∈ ⦋ 𝑛 / 𝑘⦌𝐷⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 | 
| 178 | 175, 176,
177 | cbvsum 15732 | . 2
⊢
Σ𝑘 ∈
𝐶 Σ𝑗 ∈ 𝐷 𝐸 = Σ𝑛 ∈ 𝐶 Σ𝑚 ∈ ⦋ 𝑛 / 𝑘⦌𝐷⦋𝑛 / 𝑘⦌⦋𝑚 / 𝑗⦌𝐸 | 
| 179 | 157, 170,
178 | 3eqtr4g 2801 | 1
⊢ (𝜑 → Σ𝑗 ∈ 𝐴 Σ𝑘 ∈ 𝐵 𝐸 = Σ𝑘 ∈ 𝐶 Σ𝑗 ∈ 𝐷 𝐸) |