| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cdlemefs26.b | ⊢ 𝐵  =  ( Base ‘ 𝐾 ) | 
						
							| 2 |  | cdlemefs26.l | ⊢  ≤   =  ( le ‘ 𝐾 ) | 
						
							| 3 |  | cdlemefs26.j | ⊢  ∨   =  ( join ‘ 𝐾 ) | 
						
							| 4 |  | cdlemefs26.m | ⊢  ∧   =  ( meet ‘ 𝐾 ) | 
						
							| 5 |  | cdlemefs26.a | ⊢ 𝐴  =  ( Atoms ‘ 𝐾 ) | 
						
							| 6 |  | cdlemefs26.h | ⊢ 𝐻  =  ( LHyp ‘ 𝐾 ) | 
						
							| 7 |  | cdlemefs27.u | ⊢ 𝑈  =  ( ( 𝑃  ∨  𝑄 )  ∧  𝑊 ) | 
						
							| 8 |  | cdlemefs27.d | ⊢ 𝐷  =  ( ( 𝑡  ∨  𝑈 )  ∧  ( 𝑄  ∨  ( ( 𝑃  ∨  𝑡 )  ∧  𝑊 ) ) ) | 
						
							| 9 |  | cdlemefs27.e | ⊢ 𝐸  =  ( ( 𝑃  ∨  𝑄 )  ∧  ( 𝐷  ∨  ( ( 𝑠  ∨  𝑡 )  ∧  𝑊 ) ) ) | 
						
							| 10 |  | cdlemefs27.i | ⊢ 𝐼  =  ( ℩ 𝑢  ∈  𝐵 ∀ 𝑡  ∈  𝐴 ( ( ¬  𝑡  ≤  𝑊  ∧  ¬  𝑡  ≤  ( 𝑃  ∨  𝑄 ) )  →  𝑢  =  𝐸 ) ) | 
						
							| 11 |  | cdlemefs27.n | ⊢ 𝑁  =  if ( 𝑠  ≤  ( 𝑃  ∨  𝑄 ) ,  𝐼 ,  𝐶 ) | 
						
							| 12 |  | simpr2 | ⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 )  ∧  𝑠  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑃  ≠  𝑄 ) )  →  𝑠  ≤  ( 𝑃  ∨  𝑄 ) ) | 
						
							| 13 | 12 | iftrued | ⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 )  ∧  𝑠  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑃  ≠  𝑄 ) )  →  if ( 𝑠  ≤  ( 𝑃  ∨  𝑄 ) ,  𝐼 ,  𝐶 )  =  𝐼 ) | 
						
							| 14 |  | simpl1 | ⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 )  ∧  𝑠  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑃  ≠  𝑄 ) )  →  ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 ) ) | 
						
							| 15 |  | simpl2 | ⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 )  ∧  𝑠  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑃  ≠  𝑄 ) )  →  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 ) ) | 
						
							| 16 |  | simpl3 | ⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 )  ∧  𝑠  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑃  ≠  𝑄 ) )  →  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) ) | 
						
							| 17 |  | simpr1 | ⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 )  ∧  𝑠  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑃  ≠  𝑄 ) )  →  ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 ) ) | 
						
							| 18 |  | simpr3 | ⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 )  ∧  𝑠  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑃  ≠  𝑄 ) )  →  𝑃  ≠  𝑄 ) | 
						
							| 19 | 1 2 3 4 5 6 7 8 9 10 | cdleme25cl | ⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 )  ∧  ( 𝑃  ≠  𝑄  ∧  𝑠  ≤  ( 𝑃  ∨  𝑄 ) ) )  →  𝐼  ∈  𝐵 ) | 
						
							| 20 | 14 15 16 17 18 12 19 | syl312anc | ⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 )  ∧  𝑠  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑃  ≠  𝑄 ) )  →  𝐼  ∈  𝐵 ) | 
						
							| 21 | 13 20 | eqeltrd | ⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 )  ∧  𝑠  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑃  ≠  𝑄 ) )  →  if ( 𝑠  ≤  ( 𝑃  ∨  𝑄 ) ,  𝐼 ,  𝐶 )  ∈  𝐵 ) | 
						
							| 22 | 11 21 | eqeltrid | ⊢ ( ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  ( 𝑄  ∈  𝐴  ∧  ¬  𝑄  ≤  𝑊 ) )  ∧  ( ( 𝑠  ∈  𝐴  ∧  ¬  𝑠  ≤  𝑊 )  ∧  𝑠  ≤  ( 𝑃  ∨  𝑄 )  ∧  𝑃  ≠  𝑄 ) )  →  𝑁  ∈  𝐵 ) |