| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lvolex3.l | ⊢  ≤   =  ( le ‘ 𝐾 ) | 
						
							| 2 |  | lvolex3.a | ⊢ 𝐴  =  ( Atoms ‘ 𝐾 ) | 
						
							| 3 |  | lvolex3.p | ⊢ 𝑃  =  ( LPlanes ‘ 𝐾 ) | 
						
							| 4 |  | eqid | ⊢ ( Base ‘ 𝐾 )  =  ( Base ‘ 𝐾 ) | 
						
							| 5 |  | eqid | ⊢ ( join ‘ 𝐾 )  =  ( join ‘ 𝐾 ) | 
						
							| 6 | 4 1 5 2 3 | islpln2 | ⊢ ( 𝐾  ∈  HL  →  ( 𝑋  ∈  𝑃  ↔  ( 𝑋  ∈  ( Base ‘ 𝐾 )  ∧  ∃ 𝑟  ∈  𝐴 ∃ 𝑠  ∈  𝐴 ∃ 𝑡  ∈  𝐴 ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) ) ) ) | 
						
							| 7 |  | simp1l | ⊢ ( ( ( 𝐾  ∈  HL  ∧  ( 𝑟  ∈  𝐴  ∧  𝑠  ∈  𝐴 ) )  ∧  𝑡  ∈  𝐴  ∧  ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) )  →  𝐾  ∈  HL ) | 
						
							| 8 |  | simp1rl | ⊢ ( ( ( 𝐾  ∈  HL  ∧  ( 𝑟  ∈  𝐴  ∧  𝑠  ∈  𝐴 ) )  ∧  𝑡  ∈  𝐴  ∧  ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) )  →  𝑟  ∈  𝐴 ) | 
						
							| 9 |  | simp1rr | ⊢ ( ( ( 𝐾  ∈  HL  ∧  ( 𝑟  ∈  𝐴  ∧  𝑠  ∈  𝐴 ) )  ∧  𝑡  ∈  𝐴  ∧  ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) )  →  𝑠  ∈  𝐴 ) | 
						
							| 10 |  | simp2 | ⊢ ( ( ( 𝐾  ∈  HL  ∧  ( 𝑟  ∈  𝐴  ∧  𝑠  ∈  𝐴 ) )  ∧  𝑡  ∈  𝐴  ∧  ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) )  →  𝑡  ∈  𝐴 ) | 
						
							| 11 | 5 1 2 | 3dim3 | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑟  ∈  𝐴  ∧  𝑠  ∈  𝐴  ∧  𝑡  ∈  𝐴 ) )  →  ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) | 
						
							| 12 | 7 8 9 10 11 | syl13anc | ⊢ ( ( ( 𝐾  ∈  HL  ∧  ( 𝑟  ∈  𝐴  ∧  𝑠  ∈  𝐴 ) )  ∧  𝑡  ∈  𝐴  ∧  ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) )  →  ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) | 
						
							| 13 |  | simp33 | ⊢ ( ( ( 𝐾  ∈  HL  ∧  ( 𝑟  ∈  𝐴  ∧  𝑠  ∈  𝐴 ) )  ∧  𝑡  ∈  𝐴  ∧  ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) )  →  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) | 
						
							| 14 |  | breq2 | ⊢ ( 𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 )  →  ( 𝑞  ≤  𝑋  ↔  𝑞  ≤  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) ) | 
						
							| 15 | 14 | notbid | ⊢ ( 𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 )  →  ( ¬  𝑞  ≤  𝑋  ↔  ¬  𝑞  ≤  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) ) | 
						
							| 16 | 15 | rexbidv | ⊢ ( 𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 )  →  ( ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  𝑋  ↔  ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) ) | 
						
							| 17 | 13 16 | syl | ⊢ ( ( ( 𝐾  ∈  HL  ∧  ( 𝑟  ∈  𝐴  ∧  𝑠  ∈  𝐴 ) )  ∧  𝑡  ∈  𝐴  ∧  ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) )  →  ( ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  𝑋  ↔  ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) ) | 
						
							| 18 | 12 17 | mpbird | ⊢ ( ( ( 𝐾  ∈  HL  ∧  ( 𝑟  ∈  𝐴  ∧  𝑠  ∈  𝐴 ) )  ∧  𝑡  ∈  𝐴  ∧  ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) )  →  ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  𝑋 ) | 
						
							| 19 | 18 | rexlimdv3a | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑟  ∈  𝐴  ∧  𝑠  ∈  𝐴 ) )  →  ( ∃ 𝑡  ∈  𝐴 ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) )  →  ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  𝑋 ) ) | 
						
							| 20 | 19 | rexlimdvva | ⊢ ( 𝐾  ∈  HL  →  ( ∃ 𝑟  ∈  𝐴 ∃ 𝑠  ∈  𝐴 ∃ 𝑡  ∈  𝐴 ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) )  →  ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  𝑋 ) ) | 
						
							| 21 | 20 | adantld | ⊢ ( 𝐾  ∈  HL  →  ( ( 𝑋  ∈  ( Base ‘ 𝐾 )  ∧  ∃ 𝑟  ∈  𝐴 ∃ 𝑠  ∈  𝐴 ∃ 𝑡  ∈  𝐴 ( 𝑟  ≠  𝑠  ∧  ¬  𝑡  ≤  ( 𝑟 ( join ‘ 𝐾 ) 𝑠 )  ∧  𝑋  =  ( ( 𝑟 ( join ‘ 𝐾 ) 𝑠 ) ( join ‘ 𝐾 ) 𝑡 ) ) )  →  ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  𝑋 ) ) | 
						
							| 22 | 6 21 | sylbid | ⊢ ( 𝐾  ∈  HL  →  ( 𝑋  ∈  𝑃  →  ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  𝑋 ) ) | 
						
							| 23 | 22 | imp | ⊢ ( ( 𝐾  ∈  HL  ∧  𝑋  ∈  𝑃 )  →  ∃ 𝑞  ∈  𝐴 ¬  𝑞  ≤  𝑋 ) |