| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							cdleme4.l | 
							⊢  ≤   =  ( le ‘ 𝐾 )  | 
						
						
							| 2 | 
							
								
							 | 
							cdleme4.j | 
							⊢  ∨   =  ( join ‘ 𝐾 )  | 
						
						
							| 3 | 
							
								
							 | 
							cdleme4.m | 
							⊢  ∧   =  ( meet ‘ 𝐾 )  | 
						
						
							| 4 | 
							
								
							 | 
							cdleme4.a | 
							⊢ 𝐴  =  ( Atoms ‘ 𝐾 )  | 
						
						
							| 5 | 
							
								
							 | 
							cdleme4.h | 
							⊢ 𝐻  =  ( LHyp ‘ 𝐾 )  | 
						
						
							| 6 | 
							
								
							 | 
							cdleme4.u | 
							⊢ 𝑈  =  ( ( 𝑃  ∨  𝑄 )  ∧  𝑊 )  | 
						
						
							| 7 | 
							
								
							 | 
							cdleme4.f | 
							⊢ 𝐹  =  ( ( 𝑆  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑆 )  ∧  𝑊 ) ) )  | 
						
						
							| 8 | 
							
								
							 | 
							cdleme4.g | 
							⊢ 𝐺  =  ( ( 𝑃  ∨  𝑄 )  ∧  ( 𝐹  ∨  ( ( 𝑅  ∨  𝑆 )  ∧  𝑊 ) ) )  | 
						
						
							| 9 | 
							
								
							 | 
							cdleme7.v | 
							⊢ 𝑉  =  ( ( 𝑅  ∨  𝑆 )  ∧  𝑊 )  | 
						
						
							| 10 | 
							
								
							 | 
							simp1 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑅  ≤  ( 𝑃  ∨  𝑄 ) ) )  →  ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 ) )  | 
						
						
							| 11 | 
							
								
							 | 
							simp2 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑅  ≤  ( 𝑃  ∨  𝑄 ) ) )  →  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 ) )  | 
						
						
							| 12 | 
							
								
							 | 
							simp31 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑅  ≤  ( 𝑃  ∨  𝑄 ) ) )  →  𝑆  ∈  𝐴 )  | 
						
						
							| 13 | 
							
								
							 | 
							simp33 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑅  ≤  ( 𝑃  ∨  𝑄 ) ) )  →  𝑅  ≤  ( 𝑃  ∨  𝑄 ) )  | 
						
						
							| 14 | 
							
								
							 | 
							simp32 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑅  ≤  ( 𝑃  ∨  𝑄 ) ) )  →  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 ) )  | 
						
						
							| 15 | 
							
								
							 | 
							nbrne2 | 
							⊢ ( ( 𝑅  ≤  ( 𝑃  ∨  𝑄 )  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 ) )  →  𝑅  ≠  𝑆 )  | 
						
						
							| 16 | 
							
								13 14 15
							 | 
							syl2anc | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑅  ≤  ( 𝑃  ∨  𝑄 ) ) )  →  𝑅  ≠  𝑆 )  | 
						
						
							| 17 | 
							
								1 2 3 4 5
							 | 
							lhpat | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  𝑅  ≠  𝑆 ) )  →  ( ( 𝑅  ∨  𝑆 )  ∧  𝑊 )  ∈  𝐴 )  | 
						
						
							| 18 | 
							
								10 11 12 16 17
							 | 
							syl112anc | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑅  ≤  ( 𝑃  ∨  𝑄 ) ) )  →  ( ( 𝑅  ∨  𝑆 )  ∧  𝑊 )  ∈  𝐴 )  | 
						
						
							| 19 | 
							
								9 18
							 | 
							eqeltrid | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑅  ≤  ( 𝑃  ∨  𝑄 ) ) )  →  𝑉  ∈  𝐴 )  |