| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							cdlemef44.b | 
							⊢ 𝐵  =  ( Base ‘ 𝐾 )  | 
						
						
							| 2 | 
							
								
							 | 
							cdlemef44.l | 
							⊢  ≤   =  ( le ‘ 𝐾 )  | 
						
						
							| 3 | 
							
								
							 | 
							cdlemef44.j | 
							⊢  ∨   =  ( join ‘ 𝐾 )  | 
						
						
							| 4 | 
							
								
							 | 
							cdlemef44.m | 
							⊢  ∧   =  ( meet ‘ 𝐾 )  | 
						
						
							| 5 | 
							
								
							 | 
							cdlemef44.a | 
							⊢ 𝐴  =  ( Atoms ‘ 𝐾 )  | 
						
						
							| 6 | 
							
								
							 | 
							cdlemef44.h | 
							⊢ 𝐻  =  ( LHyp ‘ 𝐾 )  | 
						
						
							| 7 | 
							
								
							 | 
							cdlemef44.u | 
							⊢ 𝑈  =  ( ( 𝑃  ∨  𝑄 )  ∧  𝑊 )  | 
						
						
							| 8 | 
							
								
							 | 
							cdlemef44.d | 
							⊢ 𝐷  =  ( ( 𝑡  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑡 )  ∧  𝑊 ) ) )  | 
						
						
							| 9 | 
							
								
							 | 
							cdlemef44.o | 
							⊢ 𝑂  =  ( ℩ 𝑧  ∈  𝐵 ∀ 𝑠  ∈  𝐴 ( ( ¬  𝑠  ≤  𝑊  ∧  ( 𝑠  ∨  ( 𝑥  ∧  𝑊 ) )  =  𝑥 )  →  𝑧  =  ( if ( 𝑠  ≤  ( 𝑃  ∨  𝑄 ) ,  𝐼 ,  ⦋ 𝑠  /  𝑡 ⦌ 𝐷 )  ∨  ( 𝑥  ∧  𝑊 ) ) ) )  | 
						
						
							| 10 | 
							
								
							 | 
							cdlemef44.f | 
							⊢ 𝐹  =  ( 𝑥  ∈  𝐵  ↦  if ( ( 𝑃  ≠  𝑄  ∧  ¬  𝑥  ≤  𝑊 ) ,  𝑂 ,  𝑥 ) )  | 
						
						
							| 11 | 
							
								
							 | 
							eqid | 
							⊢ ( ( 𝑠  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑠 )  ∧  𝑊 ) ) )  =  ( ( 𝑠  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑠 )  ∧  𝑊 ) ) )  | 
						
						
							| 12 | 
							
								
							 | 
							biid | 
							⊢ ( 𝑠  ≤  ( 𝑃  ∨  𝑄 )  ↔  𝑠  ≤  ( 𝑃  ∨  𝑄 ) )  | 
						
						
							| 13 | 
							
								
							 | 
							vex | 
							⊢ 𝑠  ∈  V  | 
						
						
							| 14 | 
							
								8 11
							 | 
							cdleme31sc | 
							⊢ ( 𝑠  ∈  V  →  ⦋ 𝑠  /  𝑡 ⦌ 𝐷  =  ( ( 𝑠  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑠 )  ∧  𝑊 ) ) ) )  | 
						
						
							| 15 | 
							
								13 14
							 | 
							ax-mp | 
							⊢ ⦋ 𝑠  /  𝑡 ⦌ 𝐷  =  ( ( 𝑠  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑠 )  ∧  𝑊 ) ) )  | 
						
						
							| 16 | 
							
								12 15
							 | 
							ifbieq2i | 
							⊢ if ( 𝑠  ≤  ( 𝑃  ∨  𝑄 ) ,  𝐼 ,  ⦋ 𝑠  /  𝑡 ⦌ 𝐷 )  =  if ( 𝑠  ≤  ( 𝑃  ∨  𝑄 ) ,  𝐼 ,  ( ( 𝑠  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑠 )  ∧  𝑊 ) ) ) )  | 
						
						
							| 17 | 
							
								
							 | 
							eqid | 
							⊢ ( ( 𝑅  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑅 )  ∧  𝑊 ) ) )  =  ( ( 𝑅  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑅 )  ∧  𝑊 ) ) )  | 
						
						
							| 18 | 
							
								1 2 3 4 5 6 7 11 16 9 10 17
							 | 
							cdlemefr31fv1 | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( 𝑃  ≠  𝑄  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 ) )  ∧  ¬  𝑅  ≤  ( 𝑃  ∨  𝑄 ) )  →  ( 𝐹 ‘ 𝑅 )  =  ( ( 𝑅  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑅 )  ∧  𝑊 ) ) ) )  | 
						
						
							| 19 | 
							
								
							 | 
							simp2rl | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( 𝑃  ≠  𝑄  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 ) )  ∧  ¬  𝑅  ≤  ( 𝑃  ∨  𝑄 ) )  →  𝑅  ∈  𝐴 )  | 
						
						
							| 20 | 
							
								8 17
							 | 
							cdleme31sc | 
							⊢ ( 𝑅  ∈  𝐴  →  ⦋ 𝑅  /  𝑡 ⦌ 𝐷  =  ( ( 𝑅  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑅 )  ∧  𝑊 ) ) ) )  | 
						
						
							| 21 | 
							
								19 20
							 | 
							syl | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( 𝑃  ≠  𝑄  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 ) )  ∧  ¬  𝑅  ≤  ( 𝑃  ∨  𝑄 ) )  →  ⦋ 𝑅  /  𝑡 ⦌ 𝐷  =  ( ( 𝑅  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑅 )  ∧  𝑊 ) ) ) )  | 
						
						
							| 22 | 
							
								18 21
							 | 
							eqtr4d | 
							⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( 𝑃  ≠  𝑄  ∧  ( 𝑅  ∈  𝐴  ∧  ¬  𝑅  ≤  𝑊 ) )  ∧  ¬  𝑅  ≤  ( 𝑃  ∨  𝑄 ) )  →  ( 𝐹 ‘ 𝑅 )  =  ⦋ 𝑅  /  𝑡 ⦌ 𝐷 )  |