| Step | Hyp | Ref
 | Expression | 
| 1 |   | reltpos 6308 | 
. . . 4
⊢ Rel tpos
𝐹 | 
| 2 | 1 | brrelex1i 4706 | 
. . 3
⊢ (𝐴tpos 𝐹𝐵 → 𝐴 ∈ V) | 
| 3 | 2 | a1i 9 | 
. 2
⊢ (𝐵 ∈ 𝑉 → (𝐴tpos 𝐹𝐵 → 𝐴 ∈ V)) | 
| 4 |   | elex 2774 | 
. . . 4
⊢ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) → 𝐴 ∈ V) | 
| 5 | 4 | adantr 276 | 
. . 3
⊢ ((𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴}𝐹𝐵) → 𝐴 ∈ V) | 
| 6 | 5 | a1i 9 | 
. 2
⊢ (𝐵 ∈ 𝑉 → ((𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴}𝐹𝐵) → 𝐴 ∈ V)) | 
| 7 |   | df-tpos 6303 | 
. . . . . 6
⊢ tpos
𝐹 = (𝐹 ∘ (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})) | 
| 8 | 7 | breqi 4039 | 
. . . . 5
⊢ (𝐴tpos 𝐹𝐵 ↔ 𝐴(𝐹 ∘ (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}))𝐵) | 
| 9 |   | brcog 4833 | 
. . . . 5
⊢ ((𝐴 ∈ V ∧ 𝐵 ∈ 𝑉) → (𝐴(𝐹 ∘ (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}))𝐵 ↔ ∃𝑦(𝐴(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})𝑦 ∧ 𝑦𝐹𝐵))) | 
| 10 | 8, 9 | bitrid 192 | 
. . . 4
⊢ ((𝐴 ∈ V ∧ 𝐵 ∈ 𝑉) → (𝐴tpos 𝐹𝐵 ↔ ∃𝑦(𝐴(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})𝑦 ∧ 𝑦𝐹𝐵))) | 
| 11 |   | funmpt 5296 | 
. . . . . . . . . . 11
⊢ Fun
(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}) | 
| 12 |   | funbrfv2b 5605 | 
. . . . . . . . . . 11
⊢ (Fun
(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}) → (𝐴(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})𝑦 ↔ (𝐴 ∈ dom (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}) ∧ ((𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})‘𝐴) = 𝑦))) | 
| 13 | 11, 12 | ax-mp 5 | 
. . . . . . . . . 10
⊢ (𝐴(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})𝑦 ↔ (𝐴 ∈ dom (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}) ∧ ((𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})‘𝐴) = 𝑦)) | 
| 14 |   | vex 2766 | 
. . . . . . . . . . . . . . . . 17
⊢ 𝑥 ∈ V | 
| 15 |   | snexg 4217 | 
. . . . . . . . . . . . . . . . 17
⊢ (𝑥 ∈ V → {𝑥} ∈ V) | 
| 16 | 14, 15 | ax-mp 5 | 
. . . . . . . . . . . . . . . 16
⊢ {𝑥} ∈ V | 
| 17 | 16 | cnvex 5208 | 
. . . . . . . . . . . . . . 15
⊢ ◡{𝑥} ∈ V | 
| 18 | 17 | uniex 4472 | 
. . . . . . . . . . . . . 14
⊢ ∪ ◡{𝑥} ∈ V | 
| 19 |   | eqid 2196 | 
. . . . . . . . . . . . . 14
⊢ (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}) = (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}) | 
| 20 | 18, 19 | dmmpti 5387 | 
. . . . . . . . . . . . 13
⊢ dom
(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}) = (◡dom 𝐹 ∪ {∅}) | 
| 21 | 20 | eleq2i 2263 | 
. . . . . . . . . . . 12
⊢ (𝐴 ∈ dom (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}) ↔ 𝐴 ∈ (◡dom 𝐹 ∪ {∅})) | 
| 22 |   | eqcom 2198 | 
. . . . . . . . . . . 12
⊢ (((𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})‘𝐴) = 𝑦 ↔ 𝑦 = ((𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})‘𝐴)) | 
| 23 | 21, 22 | anbi12i 460 | 
. . . . . . . . . . 11
⊢ ((𝐴 ∈ dom (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}) ∧ ((𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})‘𝐴) = 𝑦) ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦 = ((𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})‘𝐴))) | 
| 24 |   | snexg 4217 | 
. . . . . . . . . . . . . . . 16
⊢ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) → {𝐴} ∈ V) | 
| 25 |   | cnvexg 5207 | 
. . . . . . . . . . . . . . . 16
⊢ ({𝐴} ∈ V → ◡{𝐴} ∈ V) | 
| 26 | 24, 25 | syl 14 | 
. . . . . . . . . . . . . . 15
⊢ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) → ◡{𝐴} ∈ V) | 
| 27 |   | uniexg 4474 | 
. . . . . . . . . . . . . . 15
⊢ (◡{𝐴} ∈ V → ∪ ◡{𝐴} ∈ V) | 
| 28 | 26, 27 | syl 14 | 
. . . . . . . . . . . . . 14
⊢ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) → ∪ ◡{𝐴} ∈ V) | 
| 29 |   | sneq 3633 | 
. . . . . . . . . . . . . . . . 17
⊢ (𝑥 = 𝐴 → {𝑥} = {𝐴}) | 
| 30 | 29 | cnveqd 4842 | 
. . . . . . . . . . . . . . . 16
⊢ (𝑥 = 𝐴 → ◡{𝑥} = ◡{𝐴}) | 
| 31 | 30 | unieqd 3850 | 
. . . . . . . . . . . . . . 15
⊢ (𝑥 = 𝐴 → ∪ ◡{𝑥} = ∪ ◡{𝐴}) | 
| 32 | 31, 19 | fvmptg 5637 | 
. . . . . . . . . . . . . 14
⊢ ((𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴} ∈ V) → ((𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})‘𝐴) = ∪ ◡{𝐴}) | 
| 33 | 28, 32 | mpdan 421 | 
. . . . . . . . . . . . 13
⊢ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) → ((𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})‘𝐴) = ∪ ◡{𝐴}) | 
| 34 | 33 | eqeq2d 2208 | 
. . . . . . . . . . . 12
⊢ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) → (𝑦 = ((𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})‘𝐴) ↔ 𝑦 = ∪ ◡{𝐴})) | 
| 35 | 34 | pm5.32i 454 | 
. . . . . . . . . . 11
⊢ ((𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦 = ((𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})‘𝐴)) ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦 = ∪ ◡{𝐴})) | 
| 36 | 23, 35 | bitri 184 | 
. . . . . . . . . 10
⊢ ((𝐴 ∈ dom (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥}) ∧ ((𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})‘𝐴) = 𝑦) ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦 = ∪ ◡{𝐴})) | 
| 37 | 13, 36 | bitri 184 | 
. . . . . . . . 9
⊢ (𝐴(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})𝑦 ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦 = ∪ ◡{𝐴})) | 
| 38 |   | ancom 266 | 
. . . . . . . . 9
⊢ ((𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦 = ∪ ◡{𝐴}) ↔ (𝑦 = ∪ ◡{𝐴} ∧ 𝐴 ∈ (◡dom 𝐹 ∪ {∅}))) | 
| 39 | 37, 38 | bitri 184 | 
. . . . . . . 8
⊢ (𝐴(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})𝑦 ↔ (𝑦 = ∪ ◡{𝐴} ∧ 𝐴 ∈ (◡dom 𝐹 ∪ {∅}))) | 
| 40 | 39 | anbi1i 458 | 
. . . . . . 7
⊢ ((𝐴(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})𝑦 ∧ 𝑦𝐹𝐵) ↔ ((𝑦 = ∪ ◡{𝐴} ∧ 𝐴 ∈ (◡dom 𝐹 ∪ {∅})) ∧ 𝑦𝐹𝐵)) | 
| 41 |   | anass 401 | 
. . . . . . 7
⊢ (((𝑦 = ∪
◡{𝐴} ∧ 𝐴 ∈ (◡dom 𝐹 ∪ {∅})) ∧ 𝑦𝐹𝐵) ↔ (𝑦 = ∪ ◡{𝐴} ∧ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵))) | 
| 42 | 40, 41 | bitri 184 | 
. . . . . 6
⊢ ((𝐴(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})𝑦 ∧ 𝑦𝐹𝐵) ↔ (𝑦 = ∪ ◡{𝐴} ∧ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵))) | 
| 43 | 42 | exbii 1619 | 
. . . . 5
⊢
(∃𝑦(𝐴(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})𝑦 ∧ 𝑦𝐹𝐵) ↔ ∃𝑦(𝑦 = ∪ ◡{𝐴} ∧ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵))) | 
| 44 |   | exsimpr 1632 | 
. . . . . . 7
⊢
(∃𝑦(𝑦 = ∪
◡{𝐴} ∧ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵)) → ∃𝑦(𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵)) | 
| 45 |   | exsimpl 1631 | 
. . . . . . . 8
⊢
(∃𝑦(𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵) → ∃𝑦 𝐴 ∈ (◡dom 𝐹 ∪ {∅})) | 
| 46 |   | 19.9v 1885 | 
. . . . . . . 8
⊢
(∃𝑦 𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ↔ 𝐴 ∈ (◡dom 𝐹 ∪ {∅})) | 
| 47 | 45, 46 | sylib 122 | 
. . . . . . 7
⊢
(∃𝑦(𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵) → 𝐴 ∈ (◡dom 𝐹 ∪ {∅})) | 
| 48 | 44, 47 | syl 14 | 
. . . . . 6
⊢
(∃𝑦(𝑦 = ∪
◡{𝐴} ∧ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵)) → 𝐴 ∈ (◡dom 𝐹 ∪ {∅})) | 
| 49 |   | simpl 109 | 
. . . . . 6
⊢ ((𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴}𝐹𝐵) → 𝐴 ∈ (◡dom 𝐹 ∪ {∅})) | 
| 50 |   | breq1 4036 | 
. . . . . . . . 9
⊢ (𝑦 = ∪
◡{𝐴} → (𝑦𝐹𝐵 ↔ ∪ ◡{𝐴}𝐹𝐵)) | 
| 51 | 50 | anbi2d 464 | 
. . . . . . . 8
⊢ (𝑦 = ∪
◡{𝐴} → ((𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵) ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴}𝐹𝐵))) | 
| 52 | 51 | ceqsexgv 2893 | 
. . . . . . 7
⊢ (∪ ◡{𝐴} ∈ V → (∃𝑦(𝑦 = ∪ ◡{𝐴} ∧ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵)) ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴}𝐹𝐵))) | 
| 53 | 28, 52 | syl 14 | 
. . . . . 6
⊢ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) → (∃𝑦(𝑦 = ∪ ◡{𝐴} ∧ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵)) ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴}𝐹𝐵))) | 
| 54 | 48, 49, 53 | pm5.21nii 705 | 
. . . . 5
⊢
(∃𝑦(𝑦 = ∪
◡{𝐴} ∧ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ 𝑦𝐹𝐵)) ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴}𝐹𝐵)) | 
| 55 | 43, 54 | bitri 184 | 
. . . 4
⊢
(∃𝑦(𝐴(𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↦ ∪ ◡{𝑥})𝑦 ∧ 𝑦𝐹𝐵) ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴}𝐹𝐵)) | 
| 56 | 10, 55 | bitrdi 196 | 
. . 3
⊢ ((𝐴 ∈ V ∧ 𝐵 ∈ 𝑉) → (𝐴tpos 𝐹𝐵 ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴}𝐹𝐵))) | 
| 57 | 56 | expcom 116 | 
. 2
⊢ (𝐵 ∈ 𝑉 → (𝐴 ∈ V → (𝐴tpos 𝐹𝐵 ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴}𝐹𝐵)))) | 
| 58 | 3, 6, 57 | pm5.21ndd 706 | 
1
⊢ (𝐵 ∈ 𝑉 → (𝐴tpos 𝐹𝐵 ↔ (𝐴 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝐴}𝐹𝐵))) |