| Step | Hyp | Ref | Expression | 
						
							| 1 |  | hlatexch4.j | ⊢  ∨   =  ( join ‘ 𝐾 ) | 
						
							| 2 |  | hlatexch4.a | ⊢ 𝐴  =  ( Atoms ‘ 𝐾 ) | 
						
							| 3 |  | simp1 | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  𝐾  ∈  HL ) | 
						
							| 4 |  | simp21 | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  𝑃  ∈  𝐴 ) | 
						
							| 5 |  | simp22 | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  𝑄  ∈  𝐴 ) | 
						
							| 6 |  | eqid | ⊢ ( le ‘ 𝐾 )  =  ( le ‘ 𝐾 ) | 
						
							| 7 | 6 1 2 | hlatlej2 | ⊢ ( ( 𝐾  ∈  HL  ∧  𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 )  →  𝑄 ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 ) ) | 
						
							| 8 | 3 4 5 7 | syl3anc | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  𝑄 ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 ) ) | 
						
							| 9 |  | simp23 | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  𝑅  ∈  𝐴 ) | 
						
							| 10 | 6 1 2 | hlatlej2 | ⊢ ( ( 𝐾  ∈  HL  ∧  𝑃  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  →  𝑅 ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑅 ) ) | 
						
							| 11 | 3 4 9 10 | syl3anc | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  𝑅 ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑅 ) ) | 
						
							| 12 |  | simp3r | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) | 
						
							| 13 | 11 12 | breqtrrd | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  𝑅 ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 ) ) | 
						
							| 14 |  | hllat | ⊢ ( 𝐾  ∈  HL  →  𝐾  ∈  Lat ) | 
						
							| 15 | 14 | 3ad2ant1 | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  𝐾  ∈  Lat ) | 
						
							| 16 |  | eqid | ⊢ ( Base ‘ 𝐾 )  =  ( Base ‘ 𝐾 ) | 
						
							| 17 | 16 2 | atbase | ⊢ ( 𝑄  ∈  𝐴  →  𝑄  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 18 | 5 17 | syl | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  𝑄  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 19 | 16 2 | atbase | ⊢ ( 𝑅  ∈  𝐴  →  𝑅  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 20 | 9 19 | syl | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  𝑅  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 21 | 16 1 2 | hlatjcl | ⊢ ( ( 𝐾  ∈  HL  ∧  𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 )  →  ( 𝑃  ∨  𝑄 )  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 22 | 3 4 5 21 | syl3anc | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  ( 𝑃  ∨  𝑄 )  ∈  ( Base ‘ 𝐾 ) ) | 
						
							| 23 | 16 6 1 | latjle12 | ⊢ ( ( 𝐾  ∈  Lat  ∧  ( 𝑄  ∈  ( Base ‘ 𝐾 )  ∧  𝑅  ∈  ( Base ‘ 𝐾 )  ∧  ( 𝑃  ∨  𝑄 )  ∈  ( Base ‘ 𝐾 ) ) )  →  ( ( 𝑄 ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 )  ∧  𝑅 ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 ) )  ↔  ( 𝑄  ∨  𝑅 ) ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 ) ) ) | 
						
							| 24 | 15 18 20 22 23 | syl13anc | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  ( ( 𝑄 ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 )  ∧  𝑅 ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 ) )  ↔  ( 𝑄  ∨  𝑅 ) ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 ) ) ) | 
						
							| 25 | 8 13 24 | mpbi2and | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  ( 𝑄  ∨  𝑅 ) ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 ) ) | 
						
							| 26 |  | simp3l | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  𝑄  ≠  𝑅 ) | 
						
							| 27 | 6 1 2 | ps-1 | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴  ∧  𝑄  ≠  𝑅 )  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 ) )  →  ( ( 𝑄  ∨  𝑅 ) ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 )  ↔  ( 𝑄  ∨  𝑅 )  =  ( 𝑃  ∨  𝑄 ) ) ) | 
						
							| 28 | 3 5 9 26 4 5 27 | syl132anc | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  ( ( 𝑄  ∨  𝑅 ) ( le ‘ 𝐾 ) ( 𝑃  ∨  𝑄 )  ↔  ( 𝑄  ∨  𝑅 )  =  ( 𝑃  ∨  𝑄 ) ) ) | 
						
							| 29 | 25 28 | mpbid | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  ( 𝑄  ∨  𝑅 )  =  ( 𝑃  ∨  𝑄 ) ) | 
						
							| 30 | 29 | eqcomd | ⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑄  ≠  𝑅  ∧  ( 𝑃  ∨  𝑄 )  =  ( 𝑃  ∨  𝑅 ) ) )  →  ( 𝑃  ∨  𝑄 )  =  ( 𝑄  ∨  𝑅 ) ) |