| Step | Hyp | Ref
 | Expression | 
| 1 |   | simpl 109 | 
. . . . . . . 8
⊢ (((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇) → (𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆)) | 
| 2 | 1 | reximi 2594 | 
. . . . . . 7
⊢
(∃𝑞 ∈
𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇) → ∃𝑞 ∈ 𝐵 (𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆)) | 
| 3 | 2 | reximi 2594 | 
. . . . . 6
⊢
(∃𝑝 ∈
𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇) → ∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 (𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆)) | 
| 4 |   | eropr.1 | 
. . . . . . . . . 10
⊢ 𝐽 = (𝐴 / 𝑅) | 
| 5 | 4 | eleq2i 2263 | 
. . . . . . . . 9
⊢ (𝑥 ∈ 𝐽 ↔ 𝑥 ∈ (𝐴 / 𝑅)) | 
| 6 |   | vex 2766 | 
. . . . . . . . . 10
⊢ 𝑥 ∈ V | 
| 7 | 6 | elqs 6645 | 
. . . . . . . . 9
⊢ (𝑥 ∈ (𝐴 / 𝑅) ↔ ∃𝑝 ∈ 𝐴 𝑥 = [𝑝]𝑅) | 
| 8 | 5, 7 | bitri 184 | 
. . . . . . . 8
⊢ (𝑥 ∈ 𝐽 ↔ ∃𝑝 ∈ 𝐴 𝑥 = [𝑝]𝑅) | 
| 9 |   | eropr.2 | 
. . . . . . . . . 10
⊢ 𝐾 = (𝐵 / 𝑆) | 
| 10 | 9 | eleq2i 2263 | 
. . . . . . . . 9
⊢ (𝑦 ∈ 𝐾 ↔ 𝑦 ∈ (𝐵 / 𝑆)) | 
| 11 |   | vex 2766 | 
. . . . . . . . . 10
⊢ 𝑦 ∈ V | 
| 12 | 11 | elqs 6645 | 
. . . . . . . . 9
⊢ (𝑦 ∈ (𝐵 / 𝑆) ↔ ∃𝑞 ∈ 𝐵 𝑦 = [𝑞]𝑆) | 
| 13 | 10, 12 | bitri 184 | 
. . . . . . . 8
⊢ (𝑦 ∈ 𝐾 ↔ ∃𝑞 ∈ 𝐵 𝑦 = [𝑞]𝑆) | 
| 14 | 8, 13 | anbi12i 460 | 
. . . . . . 7
⊢ ((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ↔ (∃𝑝 ∈ 𝐴 𝑥 = [𝑝]𝑅 ∧ ∃𝑞 ∈ 𝐵 𝑦 = [𝑞]𝑆)) | 
| 15 |   | reeanv 2667 | 
. . . . . . 7
⊢
(∃𝑝 ∈
𝐴 ∃𝑞 ∈ 𝐵 (𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ↔ (∃𝑝 ∈ 𝐴 𝑥 = [𝑝]𝑅 ∧ ∃𝑞 ∈ 𝐵 𝑦 = [𝑞]𝑆)) | 
| 16 | 14, 15 | bitr4i 187 | 
. . . . . 6
⊢ ((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ↔ ∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 (𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆)) | 
| 17 | 3, 16 | sylibr 134 | 
. . . . 5
⊢
(∃𝑝 ∈
𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇) → (𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾)) | 
| 18 | 17 | pm4.71ri 392 | 
. . . 4
⊢
(∃𝑝 ∈
𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇) ↔ ((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ ∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇))) | 
| 19 |   | eropr.3 | 
. . . . . . . 8
⊢ (𝜑 → 𝑇 ∈ 𝑍) | 
| 20 |   | eropr.4 | 
. . . . . . . 8
⊢ (𝜑 → 𝑅 Er 𝑈) | 
| 21 |   | eropr.5 | 
. . . . . . . 8
⊢ (𝜑 → 𝑆 Er 𝑉) | 
| 22 |   | eropr.6 | 
. . . . . . . 8
⊢ (𝜑 → 𝑇 Er 𝑊) | 
| 23 |   | eropr.7 | 
. . . . . . . 8
⊢ (𝜑 → 𝐴 ⊆ 𝑈) | 
| 24 |   | eropr.8 | 
. . . . . . . 8
⊢ (𝜑 → 𝐵 ⊆ 𝑉) | 
| 25 |   | eropr.9 | 
. . . . . . . 8
⊢ (𝜑 → 𝐶 ⊆ 𝑊) | 
| 26 |   | eropr.10 | 
. . . . . . . 8
⊢ (𝜑 → + :(𝐴 × 𝐵)⟶𝐶) | 
| 27 |   | eropr.11 | 
. . . . . . . 8
⊢ ((𝜑 ∧ ((𝑟 ∈ 𝐴 ∧ 𝑠 ∈ 𝐴) ∧ (𝑡 ∈ 𝐵 ∧ 𝑢 ∈ 𝐵))) → ((𝑟𝑅𝑠 ∧ 𝑡𝑆𝑢) → (𝑟 + 𝑡)𝑇(𝑠 + 𝑢))) | 
| 28 | 4, 9, 19, 20, 21, 22, 23, 24, 25, 26, 27 | eroveu 6685 | 
. . . . . . 7
⊢ ((𝜑 ∧ (𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾)) → ∃!𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)) | 
| 29 |   | iota1 5233 | 
. . . . . . 7
⊢
(∃!𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇) → (∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇) ↔ (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)) = 𝑧)) | 
| 30 | 28, 29 | syl 14 | 
. . . . . 6
⊢ ((𝜑 ∧ (𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾)) → (∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇) ↔ (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)) = 𝑧)) | 
| 31 |   | eqcom 2198 | 
. . . . . 6
⊢
((℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)) = 𝑧 ↔ 𝑧 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇))) | 
| 32 | 30, 31 | bitrdi 196 | 
. . . . 5
⊢ ((𝜑 ∧ (𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾)) → (∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇) ↔ 𝑧 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)))) | 
| 33 | 32 | pm5.32da 452 | 
. . . 4
⊢ (𝜑 → (((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ ∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)) ↔ ((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ 𝑧 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇))))) | 
| 34 | 18, 33 | bitrid 192 | 
. . 3
⊢ (𝜑 → (∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇) ↔ ((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ 𝑧 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇))))) | 
| 35 | 34 | oprabbidv 5976 | 
. 2
⊢ (𝜑 → {〈〈𝑥, 𝑦〉, 𝑧〉 ∣ ∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)} = {〈〈𝑥, 𝑦〉, 𝑧〉 ∣ ((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ 𝑧 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)))}) | 
| 36 |   | eropr.12 | 
. 2
⊢  ⨣ =
{〈〈𝑥, 𝑦〉, 𝑧〉 ∣ ∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)} | 
| 37 |   | df-mpo 5927 | 
. . 3
⊢ (𝑥 ∈ 𝐽, 𝑦 ∈ 𝐾 ↦ (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇))) = {〈〈𝑥, 𝑦〉, 𝑤〉 ∣ ((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ 𝑤 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)))} | 
| 38 |   | nfv 1542 | 
. . . 4
⊢
Ⅎ𝑤((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ 𝑧 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇))) | 
| 39 |   | nfv 1542 | 
. . . . 5
⊢
Ⅎ𝑧(𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) | 
| 40 |   | nfiota1 5221 | 
. . . . . 6
⊢
Ⅎ𝑧(℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)) | 
| 41 | 40 | nfeq2 2351 | 
. . . . 5
⊢
Ⅎ𝑧 𝑤 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)) | 
| 42 | 39, 41 | nfan 1579 | 
. . . 4
⊢
Ⅎ𝑧((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ 𝑤 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇))) | 
| 43 |   | eqeq1 2203 | 
. . . . 5
⊢ (𝑧 = 𝑤 → (𝑧 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)) ↔ 𝑤 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)))) | 
| 44 | 43 | anbi2d 464 | 
. . . 4
⊢ (𝑧 = 𝑤 → (((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ 𝑧 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇))) ↔ ((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ 𝑤 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇))))) | 
| 45 | 38, 42, 44 | cbvoprab3 5998 | 
. . 3
⊢
{〈〈𝑥,
𝑦〉, 𝑧〉 ∣ ((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ 𝑧 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)))} = {〈〈𝑥, 𝑦〉, 𝑤〉 ∣ ((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ 𝑤 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)))} | 
| 46 | 37, 45 | eqtr4i 2220 | 
. 2
⊢ (𝑥 ∈ 𝐽, 𝑦 ∈ 𝐾 ↦ (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇))) = {〈〈𝑥, 𝑦〉, 𝑧〉 ∣ ((𝑥 ∈ 𝐽 ∧ 𝑦 ∈ 𝐾) ∧ 𝑧 = (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)))} | 
| 47 | 35, 36, 46 | 3eqtr4g 2254 | 
1
⊢ (𝜑 → ⨣ = (𝑥 ∈ 𝐽, 𝑦 ∈ 𝐾 ↦ (℩𝑧∃𝑝 ∈ 𝐴 ∃𝑞 ∈ 𝐵 ((𝑥 = [𝑝]𝑅 ∧ 𝑦 = [𝑞]𝑆) ∧ 𝑧 = [(𝑝 + 𝑞)]𝑇)))) |