| Step | Hyp | Ref
 | Expression | 
| 1 |   | restfn 12914 | 
. . . . . 6
⊢ 
↾t Fn (V × V) | 
| 2 |   | elex 2774 | 
. . . . . 6
⊢ (𝐵 ∈ 𝑉 → 𝐵 ∈ V) | 
| 3 |   | elex 2774 | 
. . . . . 6
⊢ (𝐴 ∈ 𝑊 → 𝐴 ∈ V) | 
| 4 |   | fnovex 5955 | 
. . . . . 6
⊢ ((
↾t Fn (V × V) ∧ 𝐵 ∈ V ∧ 𝐴 ∈ V) → (𝐵 ↾t 𝐴) ∈ V) | 
| 5 | 1, 2, 3, 4 | mp3an3an 1354 | 
. . . . 5
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (𝐵 ↾t 𝐴) ∈ V) | 
| 6 |   | eltg3 14293 | 
. . . . 5
⊢ ((𝐵 ↾t 𝐴) ∈ V → (𝑥 ∈ (topGen‘(𝐵 ↾t 𝐴)) ↔ ∃𝑦(𝑦 ⊆ (𝐵 ↾t 𝐴) ∧ 𝑥 = ∪ 𝑦))) | 
| 7 | 5, 6 | syl 14 | 
. . . 4
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (𝑥 ∈ (topGen‘(𝐵 ↾t 𝐴)) ↔ ∃𝑦(𝑦 ⊆ (𝐵 ↾t 𝐴) ∧ 𝑥 = ∪ 𝑦))) | 
| 8 |   | simpll 527 | 
. . . . . . . . 9
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑦 ⊆ (𝐵 ↾t 𝐴)) → 𝐵 ∈ 𝑉) | 
| 9 |   | funmpt 5296 | 
. . . . . . . . . 10
⊢ Fun
(𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) | 
| 10 | 9 | a1i 9 | 
. . . . . . . . 9
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑦 ⊆ (𝐵 ↾t 𝐴)) → Fun (𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴))) | 
| 11 |   | restval 12916 | 
. . . . . . . . . . . 12
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (𝐵 ↾t 𝐴) = ran (𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴))) | 
| 12 | 11 | sseq2d 3213 | 
. . . . . . . . . . 11
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (𝑦 ⊆ (𝐵 ↾t 𝐴) ↔ 𝑦 ⊆ ran (𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)))) | 
| 13 | 12 | biimpa 296 | 
. . . . . . . . . 10
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑦 ⊆ (𝐵 ↾t 𝐴)) → 𝑦 ⊆ ran (𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴))) | 
| 14 |   | vex 2766 | 
. . . . . . . . . . . . 13
⊢ 𝑥 ∈ V | 
| 15 | 14 | inex1 4167 | 
. . . . . . . . . . . 12
⊢ (𝑥 ∩ 𝐴) ∈ V | 
| 16 | 15 | rgenw 2552 | 
. . . . . . . . . . 11
⊢
∀𝑥 ∈
𝐵 (𝑥 ∩ 𝐴) ∈ V | 
| 17 |   | eqid 2196 | 
. . . . . . . . . . . 12
⊢ (𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) = (𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) | 
| 18 | 17 | fnmpt 5384 | 
. . . . . . . . . . 11
⊢
(∀𝑥 ∈
𝐵 (𝑥 ∩ 𝐴) ∈ V → (𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) Fn 𝐵) | 
| 19 |   | fnima 5376 | 
. . . . . . . . . . 11
⊢ ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) Fn 𝐵 → ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝐵) = ran (𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴))) | 
| 20 | 16, 18, 19 | mp2b 8 | 
. . . . . . . . . 10
⊢ ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝐵) = ran (𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) | 
| 21 | 13, 20 | sseqtrrdi 3232 | 
. . . . . . . . 9
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑦 ⊆ (𝐵 ↾t 𝐴)) → 𝑦 ⊆ ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝐵)) | 
| 22 |   | ssimaexg 5623 | 
. . . . . . . . 9
⊢ ((𝐵 ∈ 𝑉 ∧ Fun (𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) ∧ 𝑦 ⊆ ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝐵)) → ∃𝑧(𝑧 ⊆ 𝐵 ∧ 𝑦 = ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧))) | 
| 23 | 8, 10, 21, 22 | syl3anc 1249 | 
. . . . . . . 8
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑦 ⊆ (𝐵 ↾t 𝐴)) → ∃𝑧(𝑧 ⊆ 𝐵 ∧ 𝑦 = ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧))) | 
| 24 |   | df-ima 4676 | 
. . . . . . . . . . . . . . . . 17
⊢ ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧) = ran ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) ↾ 𝑧) | 
| 25 |   | resmpt 4994 | 
. . . . . . . . . . . . . . . . . . 19
⊢ (𝑧 ⊆ 𝐵 → ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) ↾ 𝑧) = (𝑥 ∈ 𝑧 ↦ (𝑥 ∩ 𝐴))) | 
| 26 | 25 | adantl 277 | 
. . . . . . . . . . . . . . . . . 18
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) ↾ 𝑧) = (𝑥 ∈ 𝑧 ↦ (𝑥 ∩ 𝐴))) | 
| 27 | 26 | rneqd 4895 | 
. . . . . . . . . . . . . . . . 17
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → ran ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) ↾ 𝑧) = ran (𝑥 ∈ 𝑧 ↦ (𝑥 ∩ 𝐴))) | 
| 28 | 24, 27 | eqtrid 2241 | 
. . . . . . . . . . . . . . . 16
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧) = ran (𝑥 ∈ 𝑧 ↦ (𝑥 ∩ 𝐴))) | 
| 29 | 28 | unieqd 3850 | 
. . . . . . . . . . . . . . 15
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → ∪
((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧) = ∪ ran (𝑥 ∈ 𝑧 ↦ (𝑥 ∩ 𝐴))) | 
| 30 | 15 | dfiun3 4925 | 
. . . . . . . . . . . . . . 15
⊢ ∪ 𝑥 ∈ 𝑧 (𝑥 ∩ 𝐴) = ∪ ran (𝑥 ∈ 𝑧 ↦ (𝑥 ∩ 𝐴)) | 
| 31 | 29, 30 | eqtr4di 2247 | 
. . . . . . . . . . . . . 14
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → ∪
((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧) = ∪ 𝑥 ∈ 𝑧 (𝑥 ∩ 𝐴)) | 
| 32 |   | iunin1 3981 | 
. . . . . . . . . . . . . 14
⊢ ∪ 𝑥 ∈ 𝑧 (𝑥 ∩ 𝐴) = (∪
𝑥 ∈ 𝑧 𝑥 ∩ 𝐴) | 
| 33 | 31, 32 | eqtrdi 2245 | 
. . . . . . . . . . . . 13
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → ∪
((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧) = (∪
𝑥 ∈ 𝑧 𝑥 ∩ 𝐴)) | 
| 34 |   | tgvalex 12934 | 
. . . . . . . . . . . . . . 15
⊢ (𝐵 ∈ 𝑉 → (topGen‘𝐵) ∈ V) | 
| 35 | 34 | ad2antrr 488 | 
. . . . . . . . . . . . . 14
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → (topGen‘𝐵) ∈ V) | 
| 36 |   | simpr 110 | 
. . . . . . . . . . . . . . 15
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → 𝐴 ∈ 𝑊) | 
| 37 | 36 | adantr 276 | 
. . . . . . . . . . . . . 14
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → 𝐴 ∈ 𝑊) | 
| 38 |   | uniiun 3970 | 
. . . . . . . . . . . . . . . 16
⊢ ∪ 𝑧 =
∪ 𝑥 ∈ 𝑧 𝑥 | 
| 39 |   | eltg3i 14292 | 
. . . . . . . . . . . . . . . 16
⊢ ((𝐵 ∈ 𝑉 ∧ 𝑧 ⊆ 𝐵) → ∪ 𝑧 ∈ (topGen‘𝐵)) | 
| 40 | 38, 39 | eqeltrrid 2284 | 
. . . . . . . . . . . . . . 15
⊢ ((𝐵 ∈ 𝑉 ∧ 𝑧 ⊆ 𝐵) → ∪
𝑥 ∈ 𝑧 𝑥 ∈ (topGen‘𝐵)) | 
| 41 | 40 | adantlr 477 | 
. . . . . . . . . . . . . 14
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → ∪
𝑥 ∈ 𝑧 𝑥 ∈ (topGen‘𝐵)) | 
| 42 |   | elrestr 12918 | 
. . . . . . . . . . . . . 14
⊢
(((topGen‘𝐵)
∈ V ∧ 𝐴 ∈
𝑊 ∧ ∪ 𝑥 ∈ 𝑧 𝑥 ∈ (topGen‘𝐵)) → (∪ 𝑥 ∈ 𝑧 𝑥 ∩ 𝐴) ∈ ((topGen‘𝐵) ↾t 𝐴)) | 
| 43 | 35, 37, 41, 42 | syl3anc 1249 | 
. . . . . . . . . . . . 13
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → (∪ 𝑥 ∈ 𝑧 𝑥 ∩ 𝐴) ∈ ((topGen‘𝐵) ↾t 𝐴)) | 
| 44 | 33, 43 | eqeltrd 2273 | 
. . . . . . . . . . . 12
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → ∪
((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧) ∈ ((topGen‘𝐵) ↾t 𝐴)) | 
| 45 |   | unieq 3848 | 
. . . . . . . . . . . . 13
⊢ (𝑦 = ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧) → ∪ 𝑦 = ∪
((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧)) | 
| 46 | 45 | eleq1d 2265 | 
. . . . . . . . . . . 12
⊢ (𝑦 = ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧) → (∪ 𝑦 ∈ ((topGen‘𝐵) ↾t 𝐴) ↔ ∪ ((𝑥
∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧) ∈ ((topGen‘𝐵) ↾t 𝐴))) | 
| 47 | 44, 46 | syl5ibrcom 157 | 
. . . . . . . . . . 11
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → (𝑦 = ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧) → ∪ 𝑦 ∈ ((topGen‘𝐵) ↾t 𝐴))) | 
| 48 | 47 | expimpd 363 | 
. . . . . . . . . 10
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → ((𝑧 ⊆ 𝐵 ∧ 𝑦 = ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧)) → ∪ 𝑦 ∈ ((topGen‘𝐵) ↾t 𝐴))) | 
| 49 | 48 | exlimdv 1833 | 
. . . . . . . . 9
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (∃𝑧(𝑧 ⊆ 𝐵 ∧ 𝑦 = ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧)) → ∪ 𝑦 ∈ ((topGen‘𝐵) ↾t 𝐴))) | 
| 50 | 49 | adantr 276 | 
. . . . . . . 8
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑦 ⊆ (𝐵 ↾t 𝐴)) → (∃𝑧(𝑧 ⊆ 𝐵 ∧ 𝑦 = ((𝑥 ∈ 𝐵 ↦ (𝑥 ∩ 𝐴)) “ 𝑧)) → ∪ 𝑦 ∈ ((topGen‘𝐵) ↾t 𝐴))) | 
| 51 | 23, 50 | mpd 13 | 
. . . . . . 7
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑦 ⊆ (𝐵 ↾t 𝐴)) → ∪ 𝑦 ∈ ((topGen‘𝐵) ↾t 𝐴)) | 
| 52 |   | eleq1 2259 | 
. . . . . . 7
⊢ (𝑥 = ∪
𝑦 → (𝑥 ∈ ((topGen‘𝐵) ↾t 𝐴) ↔ ∪ 𝑦
∈ ((topGen‘𝐵)
↾t 𝐴))) | 
| 53 | 51, 52 | syl5ibrcom 157 | 
. . . . . 6
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑦 ⊆ (𝐵 ↾t 𝐴)) → (𝑥 = ∪ 𝑦 → 𝑥 ∈ ((topGen‘𝐵) ↾t 𝐴))) | 
| 54 | 53 | expimpd 363 | 
. . . . 5
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → ((𝑦 ⊆ (𝐵 ↾t 𝐴) ∧ 𝑥 = ∪ 𝑦) → 𝑥 ∈ ((topGen‘𝐵) ↾t 𝐴))) | 
| 55 | 54 | exlimdv 1833 | 
. . . 4
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (∃𝑦(𝑦 ⊆ (𝐵 ↾t 𝐴) ∧ 𝑥 = ∪ 𝑦) → 𝑥 ∈ ((topGen‘𝐵) ↾t 𝐴))) | 
| 56 | 7, 55 | sylbid 150 | 
. . 3
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (𝑥 ∈ (topGen‘(𝐵 ↾t 𝐴)) → 𝑥 ∈ ((topGen‘𝐵) ↾t 𝐴))) | 
| 57 | 56 | ssrdv 3189 | 
. 2
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (topGen‘(𝐵 ↾t 𝐴)) ⊆ ((topGen‘𝐵) ↾t 𝐴)) | 
| 58 |   | restval 12916 | 
. . . 4
⊢
(((topGen‘𝐵)
∈ V ∧ 𝐴 ∈
𝑊) →
((topGen‘𝐵)
↾t 𝐴) =
ran (𝑤 ∈
(topGen‘𝐵) ↦
(𝑤 ∩ 𝐴))) | 
| 59 | 34, 36, 58 | syl2an2r 595 | 
. . 3
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → ((topGen‘𝐵) ↾t 𝐴) = ran (𝑤 ∈ (topGen‘𝐵) ↦ (𝑤 ∩ 𝐴))) | 
| 60 |   | eltg3 14293 | 
. . . . . . . 8
⊢ (𝐵 ∈ 𝑉 → (𝑤 ∈ (topGen‘𝐵) ↔ ∃𝑧(𝑧 ⊆ 𝐵 ∧ 𝑤 = ∪ 𝑧))) | 
| 61 | 60 | adantr 276 | 
. . . . . . 7
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (𝑤 ∈ (topGen‘𝐵) ↔ ∃𝑧(𝑧 ⊆ 𝐵 ∧ 𝑤 = ∪ 𝑧))) | 
| 62 | 38 | ineq1i 3360 | 
. . . . . . . . . . . 12
⊢ (∪ 𝑧
∩ 𝐴) = (∪ 𝑥 ∈ 𝑧 𝑥 ∩ 𝐴) | 
| 63 | 62, 32 | eqtr4i 2220 | 
. . . . . . . . . . 11
⊢ (∪ 𝑧
∩ 𝐴) = ∪ 𝑥 ∈ 𝑧 (𝑥 ∩ 𝐴) | 
| 64 |   | simplll 533 | 
. . . . . . . . . . . . . . . 16
⊢ ((((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) ∧ 𝑥 ∈ 𝑧) → 𝐵 ∈ 𝑉) | 
| 65 |   | simpllr 534 | 
. . . . . . . . . . . . . . . 16
⊢ ((((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) ∧ 𝑥 ∈ 𝑧) → 𝐴 ∈ 𝑊) | 
| 66 |   | simpr 110 | 
. . . . . . . . . . . . . . . . 17
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → 𝑧 ⊆ 𝐵) | 
| 67 | 66 | sselda 3183 | 
. . . . . . . . . . . . . . . 16
⊢ ((((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) ∧ 𝑥 ∈ 𝑧) → 𝑥 ∈ 𝐵) | 
| 68 |   | elrestr 12918 | 
. . . . . . . . . . . . . . . 16
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊 ∧ 𝑥 ∈ 𝐵) → (𝑥 ∩ 𝐴) ∈ (𝐵 ↾t 𝐴)) | 
| 69 | 64, 65, 67, 68 | syl3anc 1249 | 
. . . . . . . . . . . . . . 15
⊢ ((((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) ∧ 𝑥 ∈ 𝑧) → (𝑥 ∩ 𝐴) ∈ (𝐵 ↾t 𝐴)) | 
| 70 | 69 | fmpttd 5717 | 
. . . . . . . . . . . . . 14
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → (𝑥 ∈ 𝑧 ↦ (𝑥 ∩ 𝐴)):𝑧⟶(𝐵 ↾t 𝐴)) | 
| 71 | 70 | frnd 5417 | 
. . . . . . . . . . . . 13
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → ran (𝑥 ∈ 𝑧 ↦ (𝑥 ∩ 𝐴)) ⊆ (𝐵 ↾t 𝐴)) | 
| 72 |   | eltg3i 14292 | 
. . . . . . . . . . . . 13
⊢ (((𝐵 ↾t 𝐴) ∈ V ∧ ran (𝑥 ∈ 𝑧 ↦ (𝑥 ∩ 𝐴)) ⊆ (𝐵 ↾t 𝐴)) → ∪ ran
(𝑥 ∈ 𝑧 ↦ (𝑥 ∩ 𝐴)) ∈ (topGen‘(𝐵 ↾t 𝐴))) | 
| 73 | 5, 71, 72 | syl2an2r 595 | 
. . . . . . . . . . . 12
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → ∪ ran
(𝑥 ∈ 𝑧 ↦ (𝑥 ∩ 𝐴)) ∈ (topGen‘(𝐵 ↾t 𝐴))) | 
| 74 | 30, 73 | eqeltrid 2283 | 
. . . . . . . . . . 11
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → ∪
𝑥 ∈ 𝑧 (𝑥 ∩ 𝐴) ∈ (topGen‘(𝐵 ↾t 𝐴))) | 
| 75 | 63, 74 | eqeltrid 2283 | 
. . . . . . . . . 10
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → (∪ 𝑧 ∩ 𝐴) ∈ (topGen‘(𝐵 ↾t 𝐴))) | 
| 76 |   | ineq1 3357 | 
. . . . . . . . . . 11
⊢ (𝑤 = ∪
𝑧 → (𝑤 ∩ 𝐴) = (∪ 𝑧 ∩ 𝐴)) | 
| 77 | 76 | eleq1d 2265 | 
. . . . . . . . . 10
⊢ (𝑤 = ∪
𝑧 → ((𝑤 ∩ 𝐴) ∈ (topGen‘(𝐵 ↾t 𝐴)) ↔ (∪
𝑧 ∩ 𝐴) ∈ (topGen‘(𝐵 ↾t 𝐴)))) | 
| 78 | 75, 77 | syl5ibrcom 157 | 
. . . . . . . . 9
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑧 ⊆ 𝐵) → (𝑤 = ∪ 𝑧 → (𝑤 ∩ 𝐴) ∈ (topGen‘(𝐵 ↾t 𝐴)))) | 
| 79 | 78 | expimpd 363 | 
. . . . . . . 8
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → ((𝑧 ⊆ 𝐵 ∧ 𝑤 = ∪ 𝑧) → (𝑤 ∩ 𝐴) ∈ (topGen‘(𝐵 ↾t 𝐴)))) | 
| 80 | 79 | exlimdv 1833 | 
. . . . . . 7
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (∃𝑧(𝑧 ⊆ 𝐵 ∧ 𝑤 = ∪ 𝑧) → (𝑤 ∩ 𝐴) ∈ (topGen‘(𝐵 ↾t 𝐴)))) | 
| 81 | 61, 80 | sylbid 150 | 
. . . . . 6
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (𝑤 ∈ (topGen‘𝐵) → (𝑤 ∩ 𝐴) ∈ (topGen‘(𝐵 ↾t 𝐴)))) | 
| 82 | 81 | imp 124 | 
. . . . 5
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) ∧ 𝑤 ∈ (topGen‘𝐵)) → (𝑤 ∩ 𝐴) ∈ (topGen‘(𝐵 ↾t 𝐴))) | 
| 83 | 82 | fmpttd 5717 | 
. . . 4
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (𝑤 ∈ (topGen‘𝐵) ↦ (𝑤 ∩ 𝐴)):(topGen‘𝐵)⟶(topGen‘(𝐵 ↾t 𝐴))) | 
| 84 | 83 | frnd 5417 | 
. . 3
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → ran (𝑤 ∈ (topGen‘𝐵) ↦ (𝑤 ∩ 𝐴)) ⊆ (topGen‘(𝐵 ↾t 𝐴))) | 
| 85 | 59, 84 | eqsstrd 3219 | 
. 2
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → ((topGen‘𝐵) ↾t 𝐴) ⊆ (topGen‘(𝐵 ↾t 𝐴))) | 
| 86 | 57, 85 | eqssd 3200 | 
1
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (topGen‘(𝐵 ↾t 𝐴)) = ((topGen‘𝐵) ↾t 𝐴)) |