| Step | Hyp | Ref | Expression | 
						
							| 1 |  | linepsubcl.n | ⊢ 𝑁  =  ( Lines ‘ 𝐾 ) | 
						
							| 2 |  | linepsubcl.c | ⊢ 𝐶  =  ( PSubCl ‘ 𝐾 ) | 
						
							| 3 |  | hllat | ⊢ ( 𝐾  ∈  HL  →  𝐾  ∈  Lat ) | 
						
							| 4 |  | eqid | ⊢ ( join ‘ 𝐾 )  =  ( join ‘ 𝐾 ) | 
						
							| 5 |  | eqid | ⊢ ( Atoms ‘ 𝐾 )  =  ( Atoms ‘ 𝐾 ) | 
						
							| 6 |  | eqid | ⊢ ( pmap ‘ 𝐾 )  =  ( pmap ‘ 𝐾 ) | 
						
							| 7 | 4 5 1 6 | isline2 | ⊢ ( 𝐾  ∈  Lat  →  ( 𝑋  ∈  𝑁  ↔  ∃ 𝑝  ∈  ( Atoms ‘ 𝐾 ) ∃ 𝑞  ∈  ( Atoms ‘ 𝐾 ) ( 𝑝  ≠  𝑞  ∧  𝑋  =  ( ( pmap ‘ 𝐾 ) ‘ ( 𝑝 ( join ‘ 𝐾 ) 𝑞 ) ) ) ) ) | 
						
							| 8 | 3 7 | syl | ⊢ ( 𝐾  ∈  HL  →  ( 𝑋  ∈  𝑁  ↔  ∃ 𝑝  ∈  ( Atoms ‘ 𝐾 ) ∃ 𝑞  ∈  ( Atoms ‘ 𝐾 ) ( 𝑝  ≠  𝑞  ∧  𝑋  =  ( ( pmap ‘ 𝐾 ) ‘ ( 𝑝 ( join ‘ 𝐾 ) 𝑞 ) ) ) ) ) | 
						
							| 9 | 3 | adantr | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑝  ∈  ( Atoms ‘ 𝐾 )  ∧  𝑞  ∈  ( Atoms ‘ 𝐾 ) ) )  →  𝐾  ∈  Lat ) | 
						
							| 10 |  | eqid | ⊢ ( Base ‘ 𝐾 )  =  ( Base ‘ 𝐾 ) | 
						
							| 11 | 10 5 | atbase | ⊢ ( 𝑝  ∈  ( Atoms ‘ 𝐾 )  →  𝑝  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 12 | 11 | ad2antrl | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑝  ∈  ( Atoms ‘ 𝐾 )  ∧  𝑞  ∈  ( Atoms ‘ 𝐾 ) ) )  →  𝑝  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 13 | 10 5 | atbase | ⊢ ( 𝑞  ∈  ( Atoms ‘ 𝐾 )  →  𝑞  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 14 | 13 | ad2antll | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑝  ∈  ( Atoms ‘ 𝐾 )  ∧  𝑞  ∈  ( Atoms ‘ 𝐾 ) ) )  →  𝑞  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 15 | 10 4 | latjcl | ⊢ ( ( 𝐾  ∈  Lat  ∧  𝑝  ∈  ( Base ‘ 𝐾 )  ∧  𝑞  ∈  ( Base ‘ 𝐾 ) )  →  ( 𝑝 ( join ‘ 𝐾 ) 𝑞 )  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 16 | 9 12 14 15 | syl3anc | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑝  ∈  ( Atoms ‘ 𝐾 )  ∧  𝑞  ∈  ( Atoms ‘ 𝐾 ) ) )  →  ( 𝑝 ( join ‘ 𝐾 ) 𝑞 )  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 17 | 10 6 2 | pmapsubclN | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑝 ( join ‘ 𝐾 ) 𝑞 )  ∈  ( Base ‘ 𝐾 ) )  →  ( ( pmap ‘ 𝐾 ) ‘ ( 𝑝 ( join ‘ 𝐾 ) 𝑞 ) )  ∈  𝐶 ) | 
						
							| 18 | 16 17 | syldan | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑝  ∈  ( Atoms ‘ 𝐾 )  ∧  𝑞  ∈  ( Atoms ‘ 𝐾 ) ) )  →  ( ( pmap ‘ 𝐾 ) ‘ ( 𝑝 ( join ‘ 𝐾 ) 𝑞 ) )  ∈  𝐶 ) | 
						
							| 19 |  | eleq1a | ⊢ ( ( ( pmap ‘ 𝐾 ) ‘ ( 𝑝 ( join ‘ 𝐾 ) 𝑞 ) )  ∈  𝐶  →  ( 𝑋  =  ( ( pmap ‘ 𝐾 ) ‘ ( 𝑝 ( join ‘ 𝐾 ) 𝑞 ) )  →  𝑋  ∈  𝐶 ) ) | 
						
							| 20 | 18 19 | syl | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑝  ∈  ( Atoms ‘ 𝐾 )  ∧  𝑞  ∈  ( Atoms ‘ 𝐾 ) ) )  →  ( 𝑋  =  ( ( pmap ‘ 𝐾 ) ‘ ( 𝑝 ( join ‘ 𝐾 ) 𝑞 ) )  →  𝑋  ∈  𝐶 ) ) | 
						
							| 21 | 20 | adantld | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑝  ∈  ( Atoms ‘ 𝐾 )  ∧  𝑞  ∈  ( Atoms ‘ 𝐾 ) ) )  →  ( ( 𝑝  ≠  𝑞  ∧  𝑋  =  ( ( pmap ‘ 𝐾 ) ‘ ( 𝑝 ( join ‘ 𝐾 ) 𝑞 ) ) )  →  𝑋  ∈  𝐶 ) ) | 
						
							| 22 | 21 | rexlimdvva | ⊢ ( 𝐾  ∈  HL  →  ( ∃ 𝑝  ∈  ( Atoms ‘ 𝐾 ) ∃ 𝑞  ∈  ( Atoms ‘ 𝐾 ) ( 𝑝  ≠  𝑞  ∧  𝑋  =  ( ( pmap ‘ 𝐾 ) ‘ ( 𝑝 ( join ‘ 𝐾 ) 𝑞 ) ) )  →  𝑋  ∈  𝐶 ) ) | 
						
							| 23 | 8 22 | sylbid | ⊢ ( 𝐾  ∈  HL  →  ( 𝑋  ∈  𝑁  →  𝑋  ∈  𝐶 ) ) | 
						
							| 24 | 23 | imp | ⊢ ( ( 𝐾  ∈  HL  ∧  𝑋  ∈  𝑁 )  →  𝑋  ∈  𝐶 ) |