| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | elex 3501 | . 2
⊢ (𝐾 ∈ 𝐵 → 𝐾 ∈ V) | 
| 2 |  | lineset.n | . . 3
⊢ 𝑁 = (Lines‘𝐾) | 
| 3 |  | fveq2 6906 | . . . . . . 7
⊢ (𝑘 = 𝐾 → (Atoms‘𝑘) = (Atoms‘𝐾)) | 
| 4 |  | lineset.a | . . . . . . 7
⊢ 𝐴 = (Atoms‘𝐾) | 
| 5 | 3, 4 | eqtr4di 2795 | . . . . . 6
⊢ (𝑘 = 𝐾 → (Atoms‘𝑘) = 𝐴) | 
| 6 |  | fveq2 6906 | . . . . . . . . . . . . 13
⊢ (𝑘 = 𝐾 → (le‘𝑘) = (le‘𝐾)) | 
| 7 |  | lineset.l | . . . . . . . . . . . . 13
⊢  ≤ =
(le‘𝐾) | 
| 8 | 6, 7 | eqtr4di 2795 | . . . . . . . . . . . 12
⊢ (𝑘 = 𝐾 → (le‘𝑘) = ≤ ) | 
| 9 | 8 | breqd 5154 | . . . . . . . . . . 11
⊢ (𝑘 = 𝐾 → (𝑝(le‘𝑘)(𝑞(join‘𝑘)𝑟) ↔ 𝑝 ≤ (𝑞(join‘𝑘)𝑟))) | 
| 10 |  | fveq2 6906 | . . . . . . . . . . . . . 14
⊢ (𝑘 = 𝐾 → (join‘𝑘) = (join‘𝐾)) | 
| 11 |  | lineset.j | . . . . . . . . . . . . . 14
⊢  ∨ =
(join‘𝐾) | 
| 12 | 10, 11 | eqtr4di 2795 | . . . . . . . . . . . . 13
⊢ (𝑘 = 𝐾 → (join‘𝑘) = ∨ ) | 
| 13 | 12 | oveqd 7448 | . . . . . . . . . . . 12
⊢ (𝑘 = 𝐾 → (𝑞(join‘𝑘)𝑟) = (𝑞 ∨ 𝑟)) | 
| 14 | 13 | breq2d 5155 | . . . . . . . . . . 11
⊢ (𝑘 = 𝐾 → (𝑝 ≤ (𝑞(join‘𝑘)𝑟) ↔ 𝑝 ≤ (𝑞 ∨ 𝑟))) | 
| 15 | 9, 14 | bitrd 279 | . . . . . . . . . 10
⊢ (𝑘 = 𝐾 → (𝑝(le‘𝑘)(𝑞(join‘𝑘)𝑟) ↔ 𝑝 ≤ (𝑞 ∨ 𝑟))) | 
| 16 | 5, 15 | rabeqbidv 3455 | . . . . . . . . 9
⊢ (𝑘 = 𝐾 → {𝑝 ∈ (Atoms‘𝑘) ∣ 𝑝(le‘𝑘)(𝑞(join‘𝑘)𝑟)} = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)}) | 
| 17 | 16 | eqeq2d 2748 | . . . . . . . 8
⊢ (𝑘 = 𝐾 → (𝑠 = {𝑝 ∈ (Atoms‘𝑘) ∣ 𝑝(le‘𝑘)(𝑞(join‘𝑘)𝑟)} ↔ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)})) | 
| 18 | 17 | anbi2d 630 | . . . . . . 7
⊢ (𝑘 = 𝐾 → ((𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ (Atoms‘𝑘) ∣ 𝑝(le‘𝑘)(𝑞(join‘𝑘)𝑟)}) ↔ (𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)}))) | 
| 19 | 5, 18 | rexeqbidv 3347 | . . . . . 6
⊢ (𝑘 = 𝐾 → (∃𝑟 ∈ (Atoms‘𝑘)(𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ (Atoms‘𝑘) ∣ 𝑝(le‘𝑘)(𝑞(join‘𝑘)𝑟)}) ↔ ∃𝑟 ∈ 𝐴 (𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)}))) | 
| 20 | 5, 19 | rexeqbidv 3347 | . . . . 5
⊢ (𝑘 = 𝐾 → (∃𝑞 ∈ (Atoms‘𝑘)∃𝑟 ∈ (Atoms‘𝑘)(𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ (Atoms‘𝑘) ∣ 𝑝(le‘𝑘)(𝑞(join‘𝑘)𝑟)}) ↔ ∃𝑞 ∈ 𝐴 ∃𝑟 ∈ 𝐴 (𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)}))) | 
| 21 | 20 | abbidv 2808 | . . . 4
⊢ (𝑘 = 𝐾 → {𝑠 ∣ ∃𝑞 ∈ (Atoms‘𝑘)∃𝑟 ∈ (Atoms‘𝑘)(𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ (Atoms‘𝑘) ∣ 𝑝(le‘𝑘)(𝑞(join‘𝑘)𝑟)})} = {𝑠 ∣ ∃𝑞 ∈ 𝐴 ∃𝑟 ∈ 𝐴 (𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)})}) | 
| 22 |  | df-lines 39503 | . . . 4
⊢ Lines =
(𝑘 ∈ V ↦ {𝑠 ∣ ∃𝑞 ∈ (Atoms‘𝑘)∃𝑟 ∈ (Atoms‘𝑘)(𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ (Atoms‘𝑘) ∣ 𝑝(le‘𝑘)(𝑞(join‘𝑘)𝑟)})}) | 
| 23 | 4 | fvexi 6920 | . . . . 5
⊢ 𝐴 ∈ V | 
| 24 |  | df-sn 4627 | . . . . . . 7
⊢ {{𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)}} = {𝑠 ∣ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)}} | 
| 25 |  | snex 5436 | . . . . . . 7
⊢ {{𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)}} ∈ V | 
| 26 | 24, 25 | eqeltrri 2838 | . . . . . 6
⊢ {𝑠 ∣ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)}} ∈ V | 
| 27 |  | simpr 484 | . . . . . . 7
⊢ ((𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)}) → 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)}) | 
| 28 | 27 | ss2abi 4067 | . . . . . 6
⊢ {𝑠 ∣ (𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)})} ⊆ {𝑠 ∣ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)}} | 
| 29 | 26, 28 | ssexi 5322 | . . . . 5
⊢ {𝑠 ∣ (𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)})} ∈ V | 
| 30 | 23, 23, 29 | ab2rexex2 8005 | . . . 4
⊢ {𝑠 ∣ ∃𝑞 ∈ 𝐴 ∃𝑟 ∈ 𝐴 (𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)})} ∈ V | 
| 31 | 21, 22, 30 | fvmpt 7016 | . . 3
⊢ (𝐾 ∈ V →
(Lines‘𝐾) = {𝑠 ∣ ∃𝑞 ∈ 𝐴 ∃𝑟 ∈ 𝐴 (𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)})}) | 
| 32 | 2, 31 | eqtrid 2789 | . 2
⊢ (𝐾 ∈ V → 𝑁 = {𝑠 ∣ ∃𝑞 ∈ 𝐴 ∃𝑟 ∈ 𝐴 (𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)})}) | 
| 33 | 1, 32 | syl 17 | 1
⊢ (𝐾 ∈ 𝐵 → 𝑁 = {𝑠 ∣ ∃𝑞 ∈ 𝐴 ∃𝑟 ∈ 𝐴 (𝑞 ≠ 𝑟 ∧ 𝑠 = {𝑝 ∈ 𝐴 ∣ 𝑝 ≤ (𝑞 ∨ 𝑟)})}) |