| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | 0ex 5307 | . . . . 5
⊢ ∅
∈ V | 
| 2 | 1 | eldm 5911 | . . . 4
⊢ (∅
∈ dom 𝐹 ↔
∃𝑦∅𝐹𝑦) | 
| 3 |  | brtpos0 8258 | . . . . . . 7
⊢ (𝑦 ∈ V → (∅tpos
𝐹𝑦 ↔ ∅𝐹𝑦)) | 
| 4 | 3 | elv 3485 | . . . . . 6
⊢
(∅tpos 𝐹𝑦 ↔ ∅𝐹𝑦) | 
| 5 |  | 0nelrel0 5745 | . . . . . . 7
⊢ (Rel dom
tpos 𝐹 → ¬ ∅
∈ dom tpos 𝐹) | 
| 6 |  | vex 3484 | . . . . . . . 8
⊢ 𝑦 ∈ V | 
| 7 | 1, 6 | breldm 5919 | . . . . . . 7
⊢
(∅tpos 𝐹𝑦 → ∅ ∈ dom tpos
𝐹) | 
| 8 | 5, 7 | nsyl3 138 | . . . . . 6
⊢
(∅tpos 𝐹𝑦 → ¬ Rel dom tpos 𝐹) | 
| 9 | 4, 8 | sylbir 235 | . . . . 5
⊢
(∅𝐹𝑦 → ¬ Rel dom tpos 𝐹) | 
| 10 | 9 | exlimiv 1930 | . . . 4
⊢
(∃𝑦∅𝐹𝑦 → ¬ Rel dom tpos 𝐹) | 
| 11 | 2, 10 | sylbi 217 | . . 3
⊢ (∅
∈ dom 𝐹 → ¬
Rel dom tpos 𝐹) | 
| 12 | 11 | con2i 139 | . 2
⊢ (Rel dom
tpos 𝐹 → ¬ ∅
∈ dom 𝐹) | 
| 13 |  | vex 3484 | . . . . . 6
⊢ 𝑥 ∈ V | 
| 14 | 13 | eldm 5911 | . . . . 5
⊢ (𝑥 ∈ dom tpos 𝐹 ↔ ∃𝑦 𝑥tpos 𝐹𝑦) | 
| 15 |  | relcnv 6122 | . . . . . . . . . . 11
⊢ Rel ◡dom 𝐹 | 
| 16 |  | df-rel 5692 | . . . . . . . . . . 11
⊢ (Rel
◡dom 𝐹 ↔ ◡dom 𝐹 ⊆ (V × V)) | 
| 17 | 15, 16 | mpbi 230 | . . . . . . . . . 10
⊢ ◡dom 𝐹 ⊆ (V × V) | 
| 18 | 17 | sseli 3979 | . . . . . . . . 9
⊢ (𝑥 ∈ ◡dom 𝐹 → 𝑥 ∈ (V × V)) | 
| 19 | 18 | a1i 11 | . . . . . . . 8
⊢ ((¬
∅ ∈ dom 𝐹 ∧
𝑥tpos 𝐹𝑦) → (𝑥 ∈ ◡dom 𝐹 → 𝑥 ∈ (V × V))) | 
| 20 |  | elsni 4643 | . . . . . . . . . . . 12
⊢ (𝑥 ∈ {∅} → 𝑥 = ∅) | 
| 21 | 20 | breq1d 5153 | . . . . . . . . . . 11
⊢ (𝑥 ∈ {∅} → (𝑥tpos 𝐹𝑦 ↔ ∅tpos 𝐹𝑦)) | 
| 22 | 1, 6 | breldm 5919 | . . . . . . . . . . . . 13
⊢
(∅𝐹𝑦 → ∅ ∈ dom 𝐹) | 
| 23 | 22 | pm2.24d 151 | . . . . . . . . . . . 12
⊢
(∅𝐹𝑦 → (¬ ∅ ∈
dom 𝐹 → 𝑥 ∈ (V ×
V))) | 
| 24 | 4, 23 | sylbi 217 | . . . . . . . . . . 11
⊢
(∅tpos 𝐹𝑦 → (¬ ∅ ∈
dom 𝐹 → 𝑥 ∈ (V ×
V))) | 
| 25 | 21, 24 | biimtrdi 253 | . . . . . . . . . 10
⊢ (𝑥 ∈ {∅} → (𝑥tpos 𝐹𝑦 → (¬ ∅ ∈ dom 𝐹 → 𝑥 ∈ (V × V)))) | 
| 26 | 25 | com3l 89 | . . . . . . . . 9
⊢ (𝑥tpos 𝐹𝑦 → (¬ ∅ ∈ dom 𝐹 → (𝑥 ∈ {∅} → 𝑥 ∈ (V × V)))) | 
| 27 | 26 | impcom 407 | . . . . . . . 8
⊢ ((¬
∅ ∈ dom 𝐹 ∧
𝑥tpos 𝐹𝑦) → (𝑥 ∈ {∅} → 𝑥 ∈ (V × V))) | 
| 28 |  | brtpos2 8257 | . . . . . . . . . . . 12
⊢ (𝑦 ∈ V → (𝑥tpos 𝐹𝑦 ↔ (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝑥}𝐹𝑦))) | 
| 29 | 6, 28 | ax-mp 5 | . . . . . . . . . . 11
⊢ (𝑥tpos 𝐹𝑦 ↔ (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ∧ ∪ ◡{𝑥}𝐹𝑦)) | 
| 30 | 29 | simplbi 497 | . . . . . . . . . 10
⊢ (𝑥tpos 𝐹𝑦 → 𝑥 ∈ (◡dom 𝐹 ∪ {∅})) | 
| 31 |  | elun 4153 | . . . . . . . . . 10
⊢ (𝑥 ∈ (◡dom 𝐹 ∪ {∅}) ↔ (𝑥 ∈ ◡dom 𝐹 ∨ 𝑥 ∈ {∅})) | 
| 32 | 30, 31 | sylib 218 | . . . . . . . . 9
⊢ (𝑥tpos 𝐹𝑦 → (𝑥 ∈ ◡dom 𝐹 ∨ 𝑥 ∈ {∅})) | 
| 33 | 32 | adantl 481 | . . . . . . . 8
⊢ ((¬
∅ ∈ dom 𝐹 ∧
𝑥tpos 𝐹𝑦) → (𝑥 ∈ ◡dom 𝐹 ∨ 𝑥 ∈ {∅})) | 
| 34 | 19, 27, 33 | mpjaod 861 | . . . . . . 7
⊢ ((¬
∅ ∈ dom 𝐹 ∧
𝑥tpos 𝐹𝑦) → 𝑥 ∈ (V × V)) | 
| 35 | 34 | ex 412 | . . . . . 6
⊢ (¬
∅ ∈ dom 𝐹 →
(𝑥tpos 𝐹𝑦 → 𝑥 ∈ (V × V))) | 
| 36 | 35 | exlimdv 1933 | . . . . 5
⊢ (¬
∅ ∈ dom 𝐹 →
(∃𝑦 𝑥tpos 𝐹𝑦 → 𝑥 ∈ (V × V))) | 
| 37 | 14, 36 | biimtrid 242 | . . . 4
⊢ (¬
∅ ∈ dom 𝐹 →
(𝑥 ∈ dom tpos 𝐹 → 𝑥 ∈ (V × V))) | 
| 38 | 37 | ssrdv 3989 | . . 3
⊢ (¬
∅ ∈ dom 𝐹 →
dom tpos 𝐹 ⊆ (V
× V)) | 
| 39 |  | df-rel 5692 | . . 3
⊢ (Rel dom
tpos 𝐹 ↔ dom tpos
𝐹 ⊆ (V ×
V)) | 
| 40 | 38, 39 | sylibr 234 | . 2
⊢ (¬
∅ ∈ dom 𝐹 →
Rel dom tpos 𝐹) | 
| 41 | 12, 40 | impbii 209 | 1
⊢ (Rel dom
tpos 𝐹 ↔ ¬ ∅
∈ dom 𝐹) |