| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							cdleme0.l | 
							⊢  ≤   =  ( le ‘ 𝐾 )  | 
						
						
							| 2 | 
							
								
							 | 
							cdleme0.j | 
							⊢  ∨   =  ( join ‘ 𝐾 )  | 
						
						
							| 3 | 
							
								
							 | 
							cdleme0.m | 
							⊢  ∧   =  ( meet ‘ 𝐾 )  | 
						
						
							| 4 | 
							
								
							 | 
							cdleme0.a | 
							⊢ 𝐴  =  ( Atoms ‘ 𝐾 )  | 
						
						
							| 5 | 
							
								
							 | 
							cdleme0.h | 
							⊢ 𝐻  =  ( LHyp ‘ 𝐾 )  | 
						
						
							| 6 | 
							
								
							 | 
							cdleme0.u | 
							⊢ 𝑈  =  ( ( 𝑃  ∨  𝑄 )  ∧  𝑊 )  | 
						
						
							| 7 | 
							
								
							 | 
							cdleme0.b | 
							⊢ 𝐵  =  ( Base ‘ 𝐾 )  | 
						
						
							| 8 | 
							
								
							 | 
							simp1l | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 )  →  𝐾  ∈  HL )  | 
						
						
							| 9 | 
							
								8
							 | 
							hllatd | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 )  →  𝐾  ∈  Lat )  | 
						
						
							| 10 | 
							
								7 4
							 | 
							atbase | 
							⊢ ( 𝑃  ∈  𝐴  →  𝑃  ∈  𝐵 )  | 
						
						
							| 11 | 
							
								10
							 | 
							3ad2ant2 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 )  →  𝑃  ∈  𝐵 )  | 
						
						
							| 12 | 
							
								7 4
							 | 
							atbase | 
							⊢ ( 𝑄  ∈  𝐴  →  𝑄  ∈  𝐵 )  | 
						
						
							| 13 | 
							
								12
							 | 
							3ad2ant3 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 )  →  𝑄  ∈  𝐵 )  | 
						
						
							| 14 | 
							
								7 2
							 | 
							latjcl | 
							⊢ ( ( 𝐾  ∈  Lat  ∧  𝑃  ∈  𝐵  ∧  𝑄  ∈  𝐵 )  →  ( 𝑃  ∨  𝑄 )  ∈  𝐵 )  | 
						
						
							| 15 | 
							
								9 11 13 14
							 | 
							syl3anc | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 )  →  ( 𝑃  ∨  𝑄 )  ∈  𝐵 )  | 
						
						
							| 16 | 
							
								
							 | 
							simp1r | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 )  →  𝑊  ∈  𝐻 )  | 
						
						
							| 17 | 
							
								7 5
							 | 
							lhpbase | 
							⊢ ( 𝑊  ∈  𝐻  →  𝑊  ∈  𝐵 )  | 
						
						
							| 18 | 
							
								16 17
							 | 
							syl | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 )  →  𝑊  ∈  𝐵 )  | 
						
						
							| 19 | 
							
								7 3
							 | 
							latmcl | 
							⊢ ( ( 𝐾  ∈  Lat  ∧  ( 𝑃  ∨  𝑄 )  ∈  𝐵  ∧  𝑊  ∈  𝐵 )  →  ( ( 𝑃  ∨  𝑄 )  ∧  𝑊 )  ∈  𝐵 )  | 
						
						
							| 20 | 
							
								9 15 18 19
							 | 
							syl3anc | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 )  →  ( ( 𝑃  ∨  𝑄 )  ∧  𝑊 )  ∈  𝐵 )  | 
						
						
							| 21 | 
							
								6 20
							 | 
							eqeltrid | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴 )  →  𝑈  ∈  𝐵 )  |