| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							cdleme42.b | 
							⊢ 𝐵  =  ( Base ‘ 𝐾 )  | 
						
						
							| 2 | 
							
								
							 | 
							cdleme42.l | 
							⊢  ≤   =  ( le ‘ 𝐾 )  | 
						
						
							| 3 | 
							
								
							 | 
							cdleme42.j | 
							⊢  ∨   =  ( join ‘ 𝐾 )  | 
						
						
							| 4 | 
							
								
							 | 
							cdleme42.m | 
							⊢  ∧   =  ( meet ‘ 𝐾 )  | 
						
						
							| 5 | 
							
								
							 | 
							cdleme42.a | 
							⊢ 𝐴  =  ( Atoms ‘ 𝐾 )  | 
						
						
							| 6 | 
							
								
							 | 
							cdleme42.h | 
							⊢ 𝐻  =  ( LHyp ‘ 𝐾 )  | 
						
						
							| 7 | 
							
								
							 | 
							cdleme42.v | 
							⊢ 𝑉  =  ( ( 𝑅  ∨  𝑆 )  ∧  𝑊 )  | 
						
						
							| 8 | 
							
								
							 | 
							simp2r | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  ¬  𝑅  ≤  𝑊 )  | 
						
						
							| 9 | 
							
								
							 | 
							simp1l | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  𝐾  ∈  HL )  | 
						
						
							| 10 | 
							
								9
							 | 
							hllatd | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  𝐾  ∈  Lat )  | 
						
						
							| 11 | 
							
								
							 | 
							simp2l | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  𝑅  ∈  𝐴 )  | 
						
						
							| 12 | 
							
								1 5
							 | 
							atbase | 
							⊢ ( 𝑅  ∈  𝐴  →  𝑅  ∈  𝐵 )  | 
						
						
							| 13 | 
							
								11 12
							 | 
							syl | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  𝑅  ∈  𝐵 )  | 
						
						
							| 14 | 
							
								
							 | 
							simp3l | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  𝑆  ∈  𝐴 )  | 
						
						
							| 15 | 
							
								1 3 5
							 | 
							hlatjcl | 
							⊢ ( ( 𝐾  ∈  HL  ∧  𝑅  ∈  𝐴  ∧  𝑆  ∈  𝐴 )  →  ( 𝑅  ∨  𝑆 )  ∈  𝐵 )  | 
						
						
							| 16 | 
							
								9 11 14 15
							 | 
							syl3anc | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  ( 𝑅  ∨  𝑆 )  ∈  𝐵 )  | 
						
						
							| 17 | 
							
								
							 | 
							simp1r | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  𝑊  ∈  𝐻 )  | 
						
						
							| 18 | 
							
								1 6
							 | 
							lhpbase | 
							⊢ ( 𝑊  ∈  𝐻  →  𝑊  ∈  𝐵 )  | 
						
						
							| 19 | 
							
								17 18
							 | 
							syl | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  𝑊  ∈  𝐵 )  | 
						
						
							| 20 | 
							
								1 4
							 | 
							latmcl | 
							⊢ ( ( 𝐾  ∈  Lat  ∧  ( 𝑅  ∨  𝑆 )  ∈  𝐵  ∧  𝑊  ∈  𝐵 )  →  ( ( 𝑅  ∨  𝑆 )  ∧  𝑊 )  ∈  𝐵 )  | 
						
						
							| 21 | 
							
								10 16 19 20
							 | 
							syl3anc | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  ( ( 𝑅  ∨  𝑆 )  ∧  𝑊 )  ∈  𝐵 )  | 
						
						
							| 22 | 
							
								7 21
							 | 
							eqeltrid | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  𝑉  ∈  𝐵 )  | 
						
						
							| 23 | 
							
								1 2 3
							 | 
							latjle12 | 
							⊢ ( ( 𝐾  ∈  Lat  ∧  ( 𝑅  ∈  𝐵  ∧  𝑉  ∈  𝐵  ∧  𝑊  ∈  𝐵 ) )  →  ( ( 𝑅  ≤  𝑊  ∧  𝑉  ≤  𝑊 )  ↔  ( 𝑅  ∨  𝑉 )  ≤  𝑊 ) )  | 
						
						
							| 24 | 
							
								10 13 22 19 23
							 | 
							syl13anc | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  ( ( 𝑅  ≤  𝑊  ∧  𝑉  ≤  𝑊 )  ↔  ( 𝑅  ∨  𝑉 )  ≤  𝑊 ) )  | 
						
						
							| 25 | 
							
								
							 | 
							simpl | 
							⊢ ( ( 𝑅  ≤  𝑊  ∧  𝑉  ≤  𝑊 )  →  𝑅  ≤  𝑊 )  | 
						
						
							| 26 | 
							
								24 25
							 | 
							biimtrrdi | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  ( ( 𝑅  ∨  𝑉 )  ≤  𝑊  →  𝑅  ≤  𝑊 ) )  | 
						
						
							| 27 | 
							
								8 26
							 | 
							mtod | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  ¬  ( 𝑅  ∨  𝑉 )  ≤  𝑊 )  |