| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | simp2 1137 | . . 3
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴)) | 
| 2 |  | simp3l 1201 | . . 3
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → 𝑄 ≠ 𝑅) | 
| 3 |  | simp3r 1202 | . . 3
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → ¬ 𝑆 ≤ (𝑄 ∨ 𝑅)) | 
| 4 |  | eqidd 2737 | . . 3
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑅) ∨ 𝑆)) | 
| 5 |  | neeq1 3002 | . . . . 5
⊢ (𝑞 = 𝑄 → (𝑞 ≠ 𝑟 ↔ 𝑄 ≠ 𝑟)) | 
| 6 |  | oveq1 7439 | . . . . . . 7
⊢ (𝑞 = 𝑄 → (𝑞 ∨ 𝑟) = (𝑄 ∨ 𝑟)) | 
| 7 | 6 | breq2d 5154 | . . . . . 6
⊢ (𝑞 = 𝑄 → (𝑠 ≤ (𝑞 ∨ 𝑟) ↔ 𝑠 ≤ (𝑄 ∨ 𝑟))) | 
| 8 | 7 | notbid 318 | . . . . 5
⊢ (𝑞 = 𝑄 → (¬ 𝑠 ≤ (𝑞 ∨ 𝑟) ↔ ¬ 𝑠 ≤ (𝑄 ∨ 𝑟))) | 
| 9 | 6 | oveq1d 7447 | . . . . . 6
⊢ (𝑞 = 𝑄 → ((𝑞 ∨ 𝑟) ∨ 𝑠) = ((𝑄 ∨ 𝑟) ∨ 𝑠)) | 
| 10 | 9 | eqeq2d 2747 | . . . . 5
⊢ (𝑞 = 𝑄 → (((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑞 ∨ 𝑟) ∨ 𝑠) ↔ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑟) ∨ 𝑠))) | 
| 11 | 5, 8, 10 | 3anbi123d 1437 | . . . 4
⊢ (𝑞 = 𝑄 → ((𝑞 ≠ 𝑟 ∧ ¬ 𝑠 ≤ (𝑞 ∨ 𝑟) ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑞 ∨ 𝑟) ∨ 𝑠)) ↔ (𝑄 ≠ 𝑟 ∧ ¬ 𝑠 ≤ (𝑄 ∨ 𝑟) ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑟) ∨ 𝑠)))) | 
| 12 |  | neeq2 3003 | . . . . 5
⊢ (𝑟 = 𝑅 → (𝑄 ≠ 𝑟 ↔ 𝑄 ≠ 𝑅)) | 
| 13 |  | oveq2 7440 | . . . . . . 7
⊢ (𝑟 = 𝑅 → (𝑄 ∨ 𝑟) = (𝑄 ∨ 𝑅)) | 
| 14 | 13 | breq2d 5154 | . . . . . 6
⊢ (𝑟 = 𝑅 → (𝑠 ≤ (𝑄 ∨ 𝑟) ↔ 𝑠 ≤ (𝑄 ∨ 𝑅))) | 
| 15 | 14 | notbid 318 | . . . . 5
⊢ (𝑟 = 𝑅 → (¬ 𝑠 ≤ (𝑄 ∨ 𝑟) ↔ ¬ 𝑠 ≤ (𝑄 ∨ 𝑅))) | 
| 16 | 13 | oveq1d 7447 | . . . . . 6
⊢ (𝑟 = 𝑅 → ((𝑄 ∨ 𝑟) ∨ 𝑠) = ((𝑄 ∨ 𝑅) ∨ 𝑠)) | 
| 17 | 16 | eqeq2d 2747 | . . . . 5
⊢ (𝑟 = 𝑅 → (((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑟) ∨ 𝑠) ↔ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑅) ∨ 𝑠))) | 
| 18 | 12, 15, 17 | 3anbi123d 1437 | . . . 4
⊢ (𝑟 = 𝑅 → ((𝑄 ≠ 𝑟 ∧ ¬ 𝑠 ≤ (𝑄 ∨ 𝑟) ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑟) ∨ 𝑠)) ↔ (𝑄 ≠ 𝑅 ∧ ¬ 𝑠 ≤ (𝑄 ∨ 𝑅) ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑅) ∨ 𝑠)))) | 
| 19 |  | breq1 5145 | . . . . . 6
⊢ (𝑠 = 𝑆 → (𝑠 ≤ (𝑄 ∨ 𝑅) ↔ 𝑆 ≤ (𝑄 ∨ 𝑅))) | 
| 20 | 19 | notbid 318 | . . . . 5
⊢ (𝑠 = 𝑆 → (¬ 𝑠 ≤ (𝑄 ∨ 𝑅) ↔ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) | 
| 21 |  | oveq2 7440 | . . . . . 6
⊢ (𝑠 = 𝑆 → ((𝑄 ∨ 𝑅) ∨ 𝑠) = ((𝑄 ∨ 𝑅) ∨ 𝑆)) | 
| 22 | 21 | eqeq2d 2747 | . . . . 5
⊢ (𝑠 = 𝑆 → (((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑅) ∨ 𝑠) ↔ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑅) ∨ 𝑆))) | 
| 23 | 20, 22 | 3anbi23d 1440 | . . . 4
⊢ (𝑠 = 𝑆 → ((𝑄 ≠ 𝑅 ∧ ¬ 𝑠 ≤ (𝑄 ∨ 𝑅) ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑅) ∨ 𝑠)) ↔ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅) ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑅) ∨ 𝑆)))) | 
| 24 | 11, 18, 23 | rspc3ev 3638 | . . 3
⊢ (((𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅) ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑄 ∨ 𝑅) ∨ 𝑆))) → ∃𝑞 ∈ 𝐴 ∃𝑟 ∈ 𝐴 ∃𝑠 ∈ 𝐴 (𝑞 ≠ 𝑟 ∧ ¬ 𝑠 ≤ (𝑞 ∨ 𝑟) ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑞 ∨ 𝑟) ∨ 𝑠))) | 
| 25 | 1, 2, 3, 4, 24 | syl13anc 1373 | . 2
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → ∃𝑞 ∈ 𝐴 ∃𝑟 ∈ 𝐴 ∃𝑠 ∈ 𝐴 (𝑞 ≠ 𝑟 ∧ ¬ 𝑠 ≤ (𝑞 ∨ 𝑟) ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑞 ∨ 𝑟) ∨ 𝑠))) | 
| 26 |  | simp1 1136 | . . 3
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → 𝐾 ∈ HL) | 
| 27 |  | hllat 39365 | . . . . 5
⊢ (𝐾 ∈ HL → 𝐾 ∈ Lat) | 
| 28 | 27 | 3ad2ant1 1133 | . . . 4
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → 𝐾 ∈ Lat) | 
| 29 |  | simp21 1206 | . . . . 5
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → 𝑄 ∈ 𝐴) | 
| 30 |  | simp22 1207 | . . . . 5
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → 𝑅 ∈ 𝐴) | 
| 31 |  | eqid 2736 | . . . . . 6
⊢
(Base‘𝐾) =
(Base‘𝐾) | 
| 32 |  | lplni2.j | . . . . . 6
⊢  ∨ =
(join‘𝐾) | 
| 33 |  | lplni2.a | . . . . . 6
⊢ 𝐴 = (Atoms‘𝐾) | 
| 34 | 31, 32, 33 | hlatjcl 39369 | . . . . 5
⊢ ((𝐾 ∈ HL ∧ 𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴) → (𝑄 ∨ 𝑅) ∈ (Base‘𝐾)) | 
| 35 | 26, 29, 30, 34 | syl3anc 1372 | . . . 4
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → (𝑄 ∨ 𝑅) ∈ (Base‘𝐾)) | 
| 36 |  | simp23 1208 | . . . . 5
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → 𝑆 ∈ 𝐴) | 
| 37 | 31, 33 | atbase 39291 | . . . . 5
⊢ (𝑆 ∈ 𝐴 → 𝑆 ∈ (Base‘𝐾)) | 
| 38 | 36, 37 | syl 17 | . . . 4
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → 𝑆 ∈ (Base‘𝐾)) | 
| 39 | 31, 32 | latjcl 18485 | . . . 4
⊢ ((𝐾 ∈ Lat ∧ (𝑄 ∨ 𝑅) ∈ (Base‘𝐾) ∧ 𝑆 ∈ (Base‘𝐾)) → ((𝑄 ∨ 𝑅) ∨ 𝑆) ∈ (Base‘𝐾)) | 
| 40 | 28, 35, 38, 39 | syl3anc 1372 | . . 3
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → ((𝑄 ∨ 𝑅) ∨ 𝑆) ∈ (Base‘𝐾)) | 
| 41 |  | lplni2.l | . . . 4
⊢  ≤ =
(le‘𝐾) | 
| 42 |  | lplni2.p | . . . 4
⊢ 𝑃 = (LPlanes‘𝐾) | 
| 43 | 31, 41, 32, 33, 42 | islpln5 39538 | . . 3
⊢ ((𝐾 ∈ HL ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) ∈ (Base‘𝐾)) → (((𝑄 ∨ 𝑅) ∨ 𝑆) ∈ 𝑃 ↔ ∃𝑞 ∈ 𝐴 ∃𝑟 ∈ 𝐴 ∃𝑠 ∈ 𝐴 (𝑞 ≠ 𝑟 ∧ ¬ 𝑠 ≤ (𝑞 ∨ 𝑟) ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑞 ∨ 𝑟) ∨ 𝑠)))) | 
| 44 | 26, 40, 43 | syl2anc 584 | . 2
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → (((𝑄 ∨ 𝑅) ∨ 𝑆) ∈ 𝑃 ↔ ∃𝑞 ∈ 𝐴 ∃𝑟 ∈ 𝐴 ∃𝑠 ∈ 𝐴 (𝑞 ≠ 𝑟 ∧ ¬ 𝑠 ≤ (𝑞 ∨ 𝑟) ∧ ((𝑄 ∨ 𝑅) ∨ 𝑆) = ((𝑞 ∨ 𝑟) ∨ 𝑠)))) | 
| 45 | 25, 44 | mpbird 257 | 1
⊢ ((𝐾 ∈ HL ∧ (𝑄 ∈ 𝐴 ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴) ∧ (𝑄 ≠ 𝑅 ∧ ¬ 𝑆 ≤ (𝑄 ∨ 𝑅))) → ((𝑄 ∨ 𝑅) ∨ 𝑆) ∈ 𝑃) |