| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | posi.b | . . . 4
⊢ 𝐵 = (Base‘𝐾) | 
| 2 |  | posi.l | . . . 4
⊢  ≤ =
(le‘𝐾) | 
| 3 | 1, 2 | ispos 18361 | . . 3
⊢ (𝐾 ∈ Poset ↔ (𝐾 ∈ V ∧ ∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ∀𝑧 ∈ 𝐵 (𝑥 ≤ 𝑥 ∧ ((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥) → 𝑥 = 𝑦) ∧ ((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧) → 𝑥 ≤ 𝑧)))) | 
| 4 | 3 | simprbi 496 | . 2
⊢ (𝐾 ∈ Poset →
∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ∀𝑧 ∈ 𝐵 (𝑥 ≤ 𝑥 ∧ ((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥) → 𝑥 = 𝑦) ∧ ((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧) → 𝑥 ≤ 𝑧))) | 
| 5 |  | breq1 5145 | . . . . 5
⊢ (𝑥 = 𝑋 → (𝑥 ≤ 𝑥 ↔ 𝑋 ≤ 𝑥)) | 
| 6 |  | breq2 5146 | . . . . 5
⊢ (𝑥 = 𝑋 → (𝑋 ≤ 𝑥 ↔ 𝑋 ≤ 𝑋)) | 
| 7 | 5, 6 | bitrd 279 | . . . 4
⊢ (𝑥 = 𝑋 → (𝑥 ≤ 𝑥 ↔ 𝑋 ≤ 𝑋)) | 
| 8 |  | breq1 5145 | . . . . . 6
⊢ (𝑥 = 𝑋 → (𝑥 ≤ 𝑦 ↔ 𝑋 ≤ 𝑦)) | 
| 9 |  | breq2 5146 | . . . . . 6
⊢ (𝑥 = 𝑋 → (𝑦 ≤ 𝑥 ↔ 𝑦 ≤ 𝑋)) | 
| 10 | 8, 9 | anbi12d 632 | . . . . 5
⊢ (𝑥 = 𝑋 → ((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥) ↔ (𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑋))) | 
| 11 |  | eqeq1 2740 | . . . . 5
⊢ (𝑥 = 𝑋 → (𝑥 = 𝑦 ↔ 𝑋 = 𝑦)) | 
| 12 | 10, 11 | imbi12d 344 | . . . 4
⊢ (𝑥 = 𝑋 → (((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥) → 𝑥 = 𝑦) ↔ ((𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑋) → 𝑋 = 𝑦))) | 
| 13 | 8 | anbi1d 631 | . . . . 5
⊢ (𝑥 = 𝑋 → ((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧) ↔ (𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧))) | 
| 14 |  | breq1 5145 | . . . . 5
⊢ (𝑥 = 𝑋 → (𝑥 ≤ 𝑧 ↔ 𝑋 ≤ 𝑧)) | 
| 15 | 13, 14 | imbi12d 344 | . . . 4
⊢ (𝑥 = 𝑋 → (((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧) → 𝑥 ≤ 𝑧) ↔ ((𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧) → 𝑋 ≤ 𝑧))) | 
| 16 | 7, 12, 15 | 3anbi123d 1437 | . . 3
⊢ (𝑥 = 𝑋 → ((𝑥 ≤ 𝑥 ∧ ((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥) → 𝑥 = 𝑦) ∧ ((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧) → 𝑥 ≤ 𝑧)) ↔ (𝑋 ≤ 𝑋 ∧ ((𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑋) → 𝑋 = 𝑦) ∧ ((𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧) → 𝑋 ≤ 𝑧)))) | 
| 17 |  | breq2 5146 | . . . . . 6
⊢ (𝑦 = 𝑌 → (𝑋 ≤ 𝑦 ↔ 𝑋 ≤ 𝑌)) | 
| 18 |  | breq1 5145 | . . . . . 6
⊢ (𝑦 = 𝑌 → (𝑦 ≤ 𝑋 ↔ 𝑌 ≤ 𝑋)) | 
| 19 | 17, 18 | anbi12d 632 | . . . . 5
⊢ (𝑦 = 𝑌 → ((𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑋) ↔ (𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑋))) | 
| 20 |  | eqeq2 2748 | . . . . 5
⊢ (𝑦 = 𝑌 → (𝑋 = 𝑦 ↔ 𝑋 = 𝑌)) | 
| 21 | 19, 20 | imbi12d 344 | . . . 4
⊢ (𝑦 = 𝑌 → (((𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑋) → 𝑋 = 𝑦) ↔ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑋) → 𝑋 = 𝑌))) | 
| 22 |  | breq1 5145 | . . . . . 6
⊢ (𝑦 = 𝑌 → (𝑦 ≤ 𝑧 ↔ 𝑌 ≤ 𝑧)) | 
| 23 | 17, 22 | anbi12d 632 | . . . . 5
⊢ (𝑦 = 𝑌 → ((𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧) ↔ (𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑧))) | 
| 24 | 23 | imbi1d 341 | . . . 4
⊢ (𝑦 = 𝑌 → (((𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧) → 𝑋 ≤ 𝑧) ↔ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑧) → 𝑋 ≤ 𝑧))) | 
| 25 | 21, 24 | 3anbi23d 1440 | . . 3
⊢ (𝑦 = 𝑌 → ((𝑋 ≤ 𝑋 ∧ ((𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑋) → 𝑋 = 𝑦) ∧ ((𝑋 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧) → 𝑋 ≤ 𝑧)) ↔ (𝑋 ≤ 𝑋 ∧ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑋) → 𝑋 = 𝑌) ∧ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑧) → 𝑋 ≤ 𝑧)))) | 
| 26 |  | breq2 5146 | . . . . . 6
⊢ (𝑧 = 𝑍 → (𝑌 ≤ 𝑧 ↔ 𝑌 ≤ 𝑍)) | 
| 27 | 26 | anbi2d 630 | . . . . 5
⊢ (𝑧 = 𝑍 → ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑧) ↔ (𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑍))) | 
| 28 |  | breq2 5146 | . . . . 5
⊢ (𝑧 = 𝑍 → (𝑋 ≤ 𝑧 ↔ 𝑋 ≤ 𝑍)) | 
| 29 | 27, 28 | imbi12d 344 | . . . 4
⊢ (𝑧 = 𝑍 → (((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑧) → 𝑋 ≤ 𝑧) ↔ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑍) → 𝑋 ≤ 𝑍))) | 
| 30 | 29 | 3anbi3d 1443 | . . 3
⊢ (𝑧 = 𝑍 → ((𝑋 ≤ 𝑋 ∧ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑋) → 𝑋 = 𝑌) ∧ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑧) → 𝑋 ≤ 𝑧)) ↔ (𝑋 ≤ 𝑋 ∧ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑋) → 𝑋 = 𝑌) ∧ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑍) → 𝑋 ≤ 𝑍)))) | 
| 31 | 16, 25, 30 | rspc3v 3637 | . 2
⊢ ((𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵) → (∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ∀𝑧 ∈ 𝐵 (𝑥 ≤ 𝑥 ∧ ((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑥) → 𝑥 = 𝑦) ∧ ((𝑥 ≤ 𝑦 ∧ 𝑦 ≤ 𝑧) → 𝑥 ≤ 𝑧)) → (𝑋 ≤ 𝑋 ∧ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑋) → 𝑋 = 𝑌) ∧ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑍) → 𝑋 ≤ 𝑍)))) | 
| 32 | 4, 31 | mpan9 506 | 1
⊢ ((𝐾 ∈ Poset ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → (𝑋 ≤ 𝑋 ∧ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑋) → 𝑋 = 𝑌) ∧ ((𝑋 ≤ 𝑌 ∧ 𝑌 ≤ 𝑍) → 𝑋 ≤ 𝑍))) |