| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							cdleme41.b | 
							⊢ 𝐵  =  ( Base ‘ 𝐾 )  | 
						
						
							| 2 | 
							
								
							 | 
							cdleme41.l | 
							⊢  ≤   =  ( le ‘ 𝐾 )  | 
						
						
							| 3 | 
							
								
							 | 
							cdleme41.j | 
							⊢  ∨   =  ( join ‘ 𝐾 )  | 
						
						
							| 4 | 
							
								
							 | 
							cdleme41.m | 
							⊢  ∧   =  ( meet ‘ 𝐾 )  | 
						
						
							| 5 | 
							
								
							 | 
							cdleme41.a | 
							⊢ 𝐴  =  ( Atoms ‘ 𝐾 )  | 
						
						
							| 6 | 
							
								
							 | 
							cdleme41.h | 
							⊢ 𝐻  =  ( LHyp ‘ 𝐾 )  | 
						
						
							| 7 | 
							
								
							 | 
							cdleme41.u | 
							⊢ 𝑈  =  ( ( 𝑃  ∨  𝑄 )  ∧  𝑊 )  | 
						
						
							| 8 | 
							
								
							 | 
							cdleme41.d | 
							⊢ 𝐷  =  ( ( 𝑠  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑠 )  ∧  𝑊 ) ) )  | 
						
						
							| 9 | 
							
								
							 | 
							cdleme41.e | 
							⊢ 𝐸  =  ( ( 𝑡  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑡 )  ∧  𝑊 ) ) )  | 
						
						
							| 10 | 
							
								
							 | 
							cdleme41.g | 
							⊢ 𝐺  =  ( ( 𝑃  ∨  𝑄 )  ∧  ( 𝐸  ∨  ( ( 𝑠  ∨  𝑡 )  ∧  𝑊 ) ) )  | 
						
						
							| 11 | 
							
								
							 | 
							cdleme41.i | 
							⊢ 𝐼  =  ( ℩ 𝑦  ∈  𝐵 ∀ 𝑡  ∈  𝐴 ( ( ¬  𝑡  ≤  𝑊  ∧  ¬  𝑡  ≤  ( 𝑃  ∨  𝑄 ) )  →  𝑦  =  𝐺 ) )  | 
						
						
							| 12 | 
							
								
							 | 
							cdleme41.n | 
							⊢ 𝑁  =  if ( 𝑠  ≤  ( 𝑃  ∨  𝑄 ) ,  𝐼 ,  𝐷 )  | 
						
						
							| 13 | 
							
								
							 | 
							cdleme41.o | 
							⊢ 𝑂  =  ( ℩ 𝑧  ∈  𝐵 ∀ 𝑠  ∈  𝐴 ( ( ¬  𝑠  ≤  𝑊  ∧  ( 𝑠  ∨  ( 𝑥  ∧  𝑊 ) )  =  𝑥 )  →  𝑧  =  ( 𝑁  ∨  ( 𝑥  ∧  𝑊 ) ) ) )  | 
						
						
							| 14 | 
							
								
							 | 
							cdleme41.f | 
							⊢ 𝐹  =  ( 𝑥  ∈  𝐵  ↦  if ( ( 𝑃  ≠  𝑄  ∧  ¬  𝑥  ≤  𝑊 ) ,  𝑂 ,  𝑥 ) )  | 
						
						
							| 15 | 
							
								
							 | 
							cdleme34e.v | 
							⊢ 𝑉  =  ( ( 𝑅  ∨  𝑆 )  ∧  𝑊 )  | 
						
						
							| 16 | 
							
								
							 | 
							simp11 | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  ∧  𝑃  ≠  𝑄 )  →  ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 ) )  | 
						
						
							| 17 | 
							
								
							 | 
							simp2l | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  ∧  𝑃  ≠  𝑄 )  →  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 ) )  | 
						
						
							| 18 | 
							
								
							 | 
							simp2r | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  ∧  𝑃  ≠  𝑄 )  →  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  | 
						
						
							| 19 | 
							
								1 2 3 4 5 6 15
							 | 
							cdleme42a | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  →  ( 𝑅  ∨  𝑆 )  =  ( 𝑅  ∨  𝑉 ) )  | 
						
						
							| 20 | 
							
								16 17 18 19
							 | 
							syl3anc | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  ∧  𝑃  ≠  𝑄 )  →  ( 𝑅  ∨  𝑆 )  =  ( 𝑅  ∨  𝑉 ) )  | 
						
						
							| 21 | 
							
								20
							 | 
							fveq2d | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  ∧  𝑃  ≠  𝑄 )  →  ( 𝐹 ‘ ( 𝑅  ∨  𝑆 ) )  =  ( 𝐹 ‘ ( 𝑅  ∨  𝑉 ) ) )  | 
						
						
							| 22 | 
							
								1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
							 | 
							cdleme42f | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  ∧  𝑃  ≠  𝑄 )  →  ( 𝐹 ‘ ( 𝑅  ∨  𝑉 ) )  =  ( ( 𝐹 ‘ 𝑅 )  ∨  𝑉 ) )  | 
						
						
							| 23 | 
							
								21 22
							 | 
							eqtrd | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 )  ∧  ( 𝑆  ∈  𝐴  ∧  ¬  𝑆  ≤  𝑊 ) )  ∧  𝑃  ≠  𝑄 )  →  ( 𝐹 ‘ ( 𝑅  ∨  𝑆 ) )  =  ( ( 𝐹 ‘ 𝑅 )  ∨  𝑉 ) )  |