| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cdlemg4.l | ⊢  ≤   =  ( le ‘ 𝐾 ) | 
						
							| 2 |  | cdlemg4.a | ⊢ 𝐴  =  ( Atoms ‘ 𝐾 ) | 
						
							| 3 |  | cdlemg4.h | ⊢ 𝐻  =  ( LHyp ‘ 𝐾 ) | 
						
							| 4 |  | cdlemg4.t | ⊢ 𝑇  =  ( ( LTrn ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 5 |  | cdlemg4.r | ⊢ 𝑅  =  ( ( trL ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 6 |  | cdlemg4.j | ⊢  ∨   =  ( join ‘ 𝐾 ) | 
						
							| 7 |  | cdlemg4b.v | ⊢ 𝑉  =  ( 𝑅 ‘ 𝐺 ) | 
						
							| 8 |  | eqid | ⊢ ( meet ‘ 𝐾 )  =  ( meet ‘ 𝐾 ) | 
						
							| 9 | 1 6 8 2 3 4 5 | trlval2 | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  𝐺  ∈  𝑇  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 ) )  →  ( 𝑅 ‘ 𝐺 )  =  ( ( 𝑃  ∨  ( 𝐺 ‘ 𝑃 ) ) ( meet ‘ 𝐾 ) 𝑊 ) ) | 
						
							| 10 | 9 | 3com23 | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  𝐺  ∈  𝑇 )  →  ( 𝑅 ‘ 𝐺 )  =  ( ( 𝑃  ∨  ( 𝐺 ‘ 𝑃 ) ) ( meet ‘ 𝐾 ) 𝑊 ) ) | 
						
							| 11 | 7 10 | eqtrid | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  𝐺  ∈  𝑇 )  →  𝑉  =  ( ( 𝑃  ∨  ( 𝐺 ‘ 𝑃 ) ) ( meet ‘ 𝐾 ) 𝑊 ) ) | 
						
							| 12 | 11 | oveq2d | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  𝐺  ∈  𝑇 )  →  ( ( 𝐺 ‘ 𝑃 )  ∨  𝑉 )  =  ( ( 𝐺 ‘ 𝑃 )  ∨  ( ( 𝑃  ∨  ( 𝐺 ‘ 𝑃 ) ) ( meet ‘ 𝐾 ) 𝑊 ) ) ) | 
						
							| 13 |  | simp1 | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  𝐺  ∈  𝑇 )  →  ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 ) ) | 
						
							| 14 |  | simp2l | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  𝐺  ∈  𝑇 )  →  𝑃  ∈  𝐴 ) | 
						
							| 15 | 1 2 3 4 | ltrnel | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  𝐺  ∈  𝑇  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 ) )  →  ( ( 𝐺 ‘ 𝑃 )  ∈  𝐴  ∧  ¬  ( 𝐺 ‘ 𝑃 )  ≤  𝑊 ) ) | 
						
							| 16 | 15 | 3com23 | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  𝐺  ∈  𝑇 )  →  ( ( 𝐺 ‘ 𝑃 )  ∈  𝐴  ∧  ¬  ( 𝐺 ‘ 𝑃 )  ≤  𝑊 ) ) | 
						
							| 17 |  | eqid | ⊢ ( ( 𝑃  ∨  ( 𝐺 ‘ 𝑃 ) ) ( meet ‘ 𝐾 ) 𝑊 )  =  ( ( 𝑃  ∨  ( 𝐺 ‘ 𝑃 ) ) ( meet ‘ 𝐾 ) 𝑊 ) | 
						
							| 18 | 1 6 8 2 3 17 | cdleme0cq | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ( ( 𝐺 ‘ 𝑃 )  ∈  𝐴  ∧  ¬  ( 𝐺 ‘ 𝑃 )  ≤  𝑊 ) ) )  →  ( ( 𝐺 ‘ 𝑃 )  ∨  ( ( 𝑃  ∨  ( 𝐺 ‘ 𝑃 ) ) ( meet ‘ 𝐾 ) 𝑊 ) )  =  ( 𝑃  ∨  ( 𝐺 ‘ 𝑃 ) ) ) | 
						
							| 19 | 13 14 16 18 | syl12anc | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  𝐺  ∈  𝑇 )  →  ( ( 𝐺 ‘ 𝑃 )  ∨  ( ( 𝑃  ∨  ( 𝐺 ‘ 𝑃 ) ) ( meet ‘ 𝐾 ) 𝑊 ) )  =  ( 𝑃  ∨  ( 𝐺 ‘ 𝑃 ) ) ) | 
						
							| 20 | 12 19 | eqtrd | ⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 )  ∧  ( 𝑃  ∈  𝐴  ∧  ¬  𝑃  ≤  𝑊 )  ∧  𝐺  ∈  𝑇 )  →  ( ( 𝐺 ‘ 𝑃 )  ∨  𝑉 )  =  ( 𝑃  ∨  ( 𝐺 ‘ 𝑃 ) ) ) |