| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							ishlati.1 | 
							⊢ 𝐾  ∈  OML  | 
						
						
							| 2 | 
							
								
							 | 
							ishlati.2 | 
							⊢ 𝐾  ∈  CLat  | 
						
						
							| 3 | 
							
								
							 | 
							ishlati.3 | 
							⊢ 𝐾  ∈  AtLat  | 
						
						
							| 4 | 
							
								
							 | 
							ishlati.b | 
							⊢ 𝐵  =  ( Base ‘ 𝐾 )  | 
						
						
							| 5 | 
							
								
							 | 
							ishlati.l | 
							⊢  ≤   =  ( le ‘ 𝐾 )  | 
						
						
							| 6 | 
							
								
							 | 
							ishlati.s | 
							⊢  <   =  ( lt ‘ 𝐾 )  | 
						
						
							| 7 | 
							
								
							 | 
							ishlati.j | 
							⊢  ∨   =  ( join ‘ 𝐾 )  | 
						
						
							| 8 | 
							
								
							 | 
							ishlati.z | 
							⊢  0   =  ( 0. ‘ 𝐾 )  | 
						
						
							| 9 | 
							
								
							 | 
							ishlati.u | 
							⊢  1   =  ( 1. ‘ 𝐾 )  | 
						
						
							| 10 | 
							
								
							 | 
							ishlati.a | 
							⊢ 𝐴  =  ( Atoms ‘ 𝐾 )  | 
						
						
							| 11 | 
							
								
							 | 
							ishlati.9 | 
							⊢ ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( ( 𝑥  ≠  𝑦  →  ∃ 𝑧  ∈  𝐴 ( 𝑧  ≠  𝑥  ∧  𝑧  ≠  𝑦  ∧  𝑧  ≤  ( 𝑥  ∨  𝑦 ) ) )  ∧  ∀ 𝑧  ∈  𝐵 ( ( ¬  𝑥  ≤  𝑧  ∧  𝑥  ≤  ( 𝑧  ∨  𝑦 ) )  →  𝑦  ≤  ( 𝑧  ∨  𝑥 ) ) )  | 
						
						
							| 12 | 
							
								
							 | 
							ishlati.10 | 
							⊢ ∃ 𝑥  ∈  𝐵 ∃ 𝑦  ∈  𝐵 ∃ 𝑧  ∈  𝐵 ( (  0   <  𝑥  ∧  𝑥  <  𝑦 )  ∧  ( 𝑦  <  𝑧  ∧  𝑧  <   1  ) )  | 
						
						
							| 13 | 
							
								1 2 3
							 | 
							3pm3.2i | 
							⊢ ( 𝐾  ∈  OML  ∧  𝐾  ∈  CLat  ∧  𝐾  ∈  AtLat )  | 
						
						
							| 14 | 
							
								11 12
							 | 
							pm3.2i | 
							⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( ( 𝑥  ≠  𝑦  →  ∃ 𝑧  ∈  𝐴 ( 𝑧  ≠  𝑥  ∧  𝑧  ≠  𝑦  ∧  𝑧  ≤  ( 𝑥  ∨  𝑦 ) ) )  ∧  ∀ 𝑧  ∈  𝐵 ( ( ¬  𝑥  ≤  𝑧  ∧  𝑥  ≤  ( 𝑧  ∨  𝑦 ) )  →  𝑦  ≤  ( 𝑧  ∨  𝑥 ) ) )  ∧  ∃ 𝑥  ∈  𝐵 ∃ 𝑦  ∈  𝐵 ∃ 𝑧  ∈  𝐵 ( (  0   <  𝑥  ∧  𝑥  <  𝑦 )  ∧  ( 𝑦  <  𝑧  ∧  𝑧  <   1  ) ) )  | 
						
						
							| 15 | 
							
								4 5 6 7 8 9 10
							 | 
							ishlat2 | 
							⊢ ( 𝐾  ∈  HL  ↔  ( ( 𝐾  ∈  OML  ∧  𝐾  ∈  CLat  ∧  𝐾  ∈  AtLat )  ∧  ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( ( 𝑥  ≠  𝑦  →  ∃ 𝑧  ∈  𝐴 ( 𝑧  ≠  𝑥  ∧  𝑧  ≠  𝑦  ∧  𝑧  ≤  ( 𝑥  ∨  𝑦 ) ) )  ∧  ∀ 𝑧  ∈  𝐵 ( ( ¬  𝑥  ≤  𝑧  ∧  𝑥  ≤  ( 𝑧  ∨  𝑦 ) )  →  𝑦  ≤  ( 𝑧  ∨  𝑥 ) ) )  ∧  ∃ 𝑥  ∈  𝐵 ∃ 𝑦  ∈  𝐵 ∃ 𝑧  ∈  𝐵 ( (  0   <  𝑥  ∧  𝑥  <  𝑦 )  ∧  ( 𝑦  <  𝑧  ∧  𝑧  <   1  ) ) ) ) )  | 
						
						
							| 16 | 
							
								13 14 15
							 | 
							mpbir2an | 
							⊢ 𝐾  ∈  HL  |