| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | axgroth3 10872 | . 2
⊢
∃𝑦(𝑥 ∈ 𝑦 ∧ ∀𝑧 ∈ 𝑦 (∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∃𝑤 ∈ 𝑦 ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑤)) ∧ ∀𝑧(𝑧 ⊆ 𝑦 → ((𝑦 ∖ 𝑧) ≼ 𝑧 ∨ 𝑧 ∈ 𝑦))) | 
| 2 |  | elequ2 2122 | . . . . . . . . . 10
⊢ (𝑤 = 𝑣 → (𝑢 ∈ 𝑤 ↔ 𝑢 ∈ 𝑣)) | 
| 3 | 2 | imbi2d 340 | . . . . . . . . 9
⊢ (𝑤 = 𝑣 → ((𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑤) ↔ (𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑣))) | 
| 4 | 3 | albidv 1919 | . . . . . . . 8
⊢ (𝑤 = 𝑣 → (∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑤) ↔ ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑣))) | 
| 5 | 4 | cbvrexvw 3237 | . . . . . . 7
⊢
(∃𝑤 ∈
𝑦 ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑤) ↔ ∃𝑣 ∈ 𝑦 ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑣)) | 
| 6 | 5 | anbi2i 623 | . . . . . 6
⊢
((∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∃𝑤 ∈ 𝑦 ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑤)) ↔ (∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∃𝑣 ∈ 𝑦 ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑣))) | 
| 7 |  | r19.42v 3190 | . . . . . 6
⊢
(∃𝑣 ∈
𝑦 (∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑣)) ↔ (∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∃𝑣 ∈ 𝑦 ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑣))) | 
| 8 |  | sseq1 4008 | . . . . . . . . . . 11
⊢ (𝑢 = 𝑤 → (𝑢 ⊆ 𝑧 ↔ 𝑤 ⊆ 𝑧)) | 
| 9 |  | elequ1 2114 | . . . . . . . . . . 11
⊢ (𝑢 = 𝑤 → (𝑢 ∈ 𝑣 ↔ 𝑤 ∈ 𝑣)) | 
| 10 | 8, 9 | imbi12d 344 | . . . . . . . . . 10
⊢ (𝑢 = 𝑤 → ((𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑣) ↔ (𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑣))) | 
| 11 | 10 | cbvalvw 2034 | . . . . . . . . 9
⊢
(∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑣) ↔ ∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑣)) | 
| 12 | 11 | anbi2i 623 | . . . . . . . 8
⊢
((∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑣)) ↔ (∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑣))) | 
| 13 |  | 19.26 1869 | . . . . . . . 8
⊢
(∀𝑤((𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ (𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑣)) ↔ (∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑣))) | 
| 14 |  | pm4.76 518 | . . . . . . . . . 10
⊢ (((𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ (𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑣)) ↔ (𝑤 ⊆ 𝑧 → (𝑤 ∈ 𝑦 ∧ 𝑤 ∈ 𝑣))) | 
| 15 |  | elin 3966 | . . . . . . . . . . 11
⊢ (𝑤 ∈ (𝑦 ∩ 𝑣) ↔ (𝑤 ∈ 𝑦 ∧ 𝑤 ∈ 𝑣)) | 
| 16 | 15 | imbi2i 336 | . . . . . . . . . 10
⊢ ((𝑤 ⊆ 𝑧 → 𝑤 ∈ (𝑦 ∩ 𝑣)) ↔ (𝑤 ⊆ 𝑧 → (𝑤 ∈ 𝑦 ∧ 𝑤 ∈ 𝑣))) | 
| 17 | 14, 16 | bitr4i 278 | . . . . . . . . 9
⊢ (((𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ (𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑣)) ↔ (𝑤 ⊆ 𝑧 → 𝑤 ∈ (𝑦 ∩ 𝑣))) | 
| 18 | 17 | albii 1818 | . . . . . . . 8
⊢
(∀𝑤((𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ (𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑣)) ↔ ∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ (𝑦 ∩ 𝑣))) | 
| 19 | 12, 13, 18 | 3bitr2i 299 | . . . . . . 7
⊢
((∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑣)) ↔ ∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ (𝑦 ∩ 𝑣))) | 
| 20 | 19 | rexbii 3093 | . . . . . 6
⊢
(∃𝑣 ∈
𝑦 (∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑣)) ↔ ∃𝑣 ∈ 𝑦 ∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ (𝑦 ∩ 𝑣))) | 
| 21 | 6, 7, 20 | 3bitr2i 299 | . . . . 5
⊢
((∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∃𝑤 ∈ 𝑦 ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑤)) ↔ ∃𝑣 ∈ 𝑦 ∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ (𝑦 ∩ 𝑣))) | 
| 22 | 21 | ralbii 3092 | . . . 4
⊢
(∀𝑧 ∈
𝑦 (∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∃𝑤 ∈ 𝑦 ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑤)) ↔ ∀𝑧 ∈ 𝑦 ∃𝑣 ∈ 𝑦 ∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ (𝑦 ∩ 𝑣))) | 
| 23 | 22 | 3anbi2i 1158 | . . 3
⊢ ((𝑥 ∈ 𝑦 ∧ ∀𝑧 ∈ 𝑦 (∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∃𝑤 ∈ 𝑦 ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑤)) ∧ ∀𝑧(𝑧 ⊆ 𝑦 → ((𝑦 ∖ 𝑧) ≼ 𝑧 ∨ 𝑧 ∈ 𝑦))) ↔ (𝑥 ∈ 𝑦 ∧ ∀𝑧 ∈ 𝑦 ∃𝑣 ∈ 𝑦 ∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ (𝑦 ∩ 𝑣)) ∧ ∀𝑧(𝑧 ⊆ 𝑦 → ((𝑦 ∖ 𝑧) ≼ 𝑧 ∨ 𝑧 ∈ 𝑦)))) | 
| 24 | 23 | exbii 1847 | . 2
⊢
(∃𝑦(𝑥 ∈ 𝑦 ∧ ∀𝑧 ∈ 𝑦 (∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ 𝑦) ∧ ∃𝑤 ∈ 𝑦 ∀𝑢(𝑢 ⊆ 𝑧 → 𝑢 ∈ 𝑤)) ∧ ∀𝑧(𝑧 ⊆ 𝑦 → ((𝑦 ∖ 𝑧) ≼ 𝑧 ∨ 𝑧 ∈ 𝑦))) ↔ ∃𝑦(𝑥 ∈ 𝑦 ∧ ∀𝑧 ∈ 𝑦 ∃𝑣 ∈ 𝑦 ∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ (𝑦 ∩ 𝑣)) ∧ ∀𝑧(𝑧 ⊆ 𝑦 → ((𝑦 ∖ 𝑧) ≼ 𝑧 ∨ 𝑧 ∈ 𝑦)))) | 
| 25 | 1, 24 | mpbi 230 | 1
⊢
∃𝑦(𝑥 ∈ 𝑦 ∧ ∀𝑧 ∈ 𝑦 ∃𝑣 ∈ 𝑦 ∀𝑤(𝑤 ⊆ 𝑧 → 𝑤 ∈ (𝑦 ∩ 𝑣)) ∧ ∀𝑧(𝑧 ⊆ 𝑦 → ((𝑦 ∖ 𝑧) ≼ 𝑧 ∨ 𝑧 ∈ 𝑦))) |