| Step | Hyp | Ref
 | Expression | 
| 1 |   | eleq1w 2257 | 
. . . . . . 7
⊢ (𝑥 = 𝑧 → (𝑥 ∈ 𝑦 ↔ 𝑧 ∈ 𝑦)) | 
| 2 |   | equequ1 1726 | 
. . . . . . 7
⊢ (𝑥 = 𝑧 → (𝑥 = 𝑦 ↔ 𝑧 = 𝑦)) | 
| 3 |   | eleq2 2260 | 
. . . . . . 7
⊢ (𝑥 = 𝑧 → (𝑦 ∈ 𝑥 ↔ 𝑦 ∈ 𝑧)) | 
| 4 | 1, 2, 3 | 3orbi123d 1322 | 
. . . . . 6
⊢ (𝑥 = 𝑧 → ((𝑥 ∈ 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 ∈ 𝑥) ↔ (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) | 
| 5 | 4 | ralbidv 2497 | 
. . . . 5
⊢ (𝑥 = 𝑧 → (∀𝑦 ∈ On (𝑥 ∈ 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 ∈ 𝑥) ↔ ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) | 
| 6 | 5 | imbi2d 230 | 
. . . 4
⊢ (𝑥 = 𝑧 → ((EXMID →
∀𝑦 ∈ On (𝑥 ∈ 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 ∈ 𝑥)) ↔ (EXMID →
∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧)))) | 
| 7 |   | simplll 533 | 
. . . . . . . 8
⊢ ((((𝑥 ∈ On ∧ ∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) ∧ EXMID) ∧ 𝑎 ∈ On) → 𝑥 ∈ On) | 
| 8 |   | simpr 110 | 
. . . . . . . 8
⊢ ((((𝑥 ∈ On ∧ ∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) ∧ EXMID) ∧ 𝑎 ∈ On) → 𝑎 ∈ On) | 
| 9 |   | simplr 528 | 
. . . . . . . 8
⊢ ((((𝑥 ∈ On ∧ ∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) ∧ EXMID) ∧ 𝑎 ∈ On) →
EXMID) | 
| 10 |   | simpllr 534 | 
. . . . . . . . 9
⊢ ((((𝑥 ∈ On ∧ ∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) ∧ EXMID) ∧ 𝑎 ∈ On) → ∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) | 
| 11 |   | pm2.27 40 | 
. . . . . . . . . . 11
⊢
(EXMID → ((EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧)) → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) | 
| 12 | 11 | ralimdv 2565 | 
. . . . . . . . . 10
⊢
(EXMID → (∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧)) → ∀𝑧 ∈ 𝑥 ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) | 
| 13 | 12 | ad2antlr 489 | 
. . . . . . . . 9
⊢ ((((𝑥 ∈ On ∧ ∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) ∧ EXMID) ∧ 𝑎 ∈ On) →
(∀𝑧 ∈ 𝑥 (EXMID →
∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧)) → ∀𝑧 ∈ 𝑥 ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) | 
| 14 | 10, 13 | mpd 13 | 
. . . . . . . 8
⊢ ((((𝑥 ∈ On ∧ ∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) ∧ EXMID) ∧ 𝑎 ∈ On) → ∀𝑧 ∈ 𝑥 ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧)) | 
| 15 | 7, 8, 9, 14 | exmidontriimlem4 7291 | 
. . . . . . 7
⊢ ((((𝑥 ∈ On ∧ ∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) ∧ EXMID) ∧ 𝑎 ∈ On) → (𝑥 ∈ 𝑎 ∨ 𝑥 = 𝑎 ∨ 𝑎 ∈ 𝑥)) | 
| 16 | 15 | ralrimiva 2570 | 
. . . . . 6
⊢ (((𝑥 ∈ On ∧ ∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) ∧ EXMID) →
∀𝑎 ∈ On (𝑥 ∈ 𝑎 ∨ 𝑥 = 𝑎 ∨ 𝑎 ∈ 𝑥)) | 
| 17 |   | eleq2 2260 | 
. . . . . . . 8
⊢ (𝑎 = 𝑦 → (𝑥 ∈ 𝑎 ↔ 𝑥 ∈ 𝑦)) | 
| 18 |   | equequ2 1727 | 
. . . . . . . 8
⊢ (𝑎 = 𝑦 → (𝑥 = 𝑎 ↔ 𝑥 = 𝑦)) | 
| 19 |   | eleq1w 2257 | 
. . . . . . . 8
⊢ (𝑎 = 𝑦 → (𝑎 ∈ 𝑥 ↔ 𝑦 ∈ 𝑥)) | 
| 20 | 17, 18, 19 | 3orbi123d 1322 | 
. . . . . . 7
⊢ (𝑎 = 𝑦 → ((𝑥 ∈ 𝑎 ∨ 𝑥 = 𝑎 ∨ 𝑎 ∈ 𝑥) ↔ (𝑥 ∈ 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 ∈ 𝑥))) | 
| 21 | 20 | cbvralv 2729 | 
. . . . . 6
⊢
(∀𝑎 ∈ On
(𝑥 ∈ 𝑎 ∨ 𝑥 = 𝑎 ∨ 𝑎 ∈ 𝑥) ↔ ∀𝑦 ∈ On (𝑥 ∈ 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 ∈ 𝑥)) | 
| 22 | 16, 21 | sylib 122 | 
. . . . 5
⊢ (((𝑥 ∈ On ∧ ∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧))) ∧ EXMID) →
∀𝑦 ∈ On (𝑥 ∈ 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 ∈ 𝑥)) | 
| 23 | 22 | exp31 364 | 
. . . 4
⊢ (𝑥 ∈ On → (∀𝑧 ∈ 𝑥 (EXMID → ∀𝑦 ∈ On (𝑧 ∈ 𝑦 ∨ 𝑧 = 𝑦 ∨ 𝑦 ∈ 𝑧)) → (EXMID →
∀𝑦 ∈ On (𝑥 ∈ 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 ∈ 𝑥)))) | 
| 24 | 6, 23 | tfis2 4621 | 
. . 3
⊢ (𝑥 ∈ On →
(EXMID → ∀𝑦 ∈ On (𝑥 ∈ 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 ∈ 𝑥))) | 
| 25 | 24 | impcom 125 | 
. 2
⊢
((EXMID ∧ 𝑥 ∈ On) → ∀𝑦 ∈ On (𝑥 ∈ 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 ∈ 𝑥)) | 
| 26 | 25 | ralrimiva 2570 | 
1
⊢
(EXMID → ∀𝑥 ∈ On ∀𝑦 ∈ On (𝑥 ∈ 𝑦 ∨ 𝑥 = 𝑦 ∨ 𝑦 ∈ 𝑥)) |