| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							dalem.ph | 
							⊢ ( 𝜑  ↔  ( ( ( 𝐾  ∈  HL  ∧  𝐶  ∈  ( Base ‘ 𝐾 ) )  ∧  ( 𝑃  ∈  𝐴  ∧  𝑄  ∈  𝐴  ∧  𝑅  ∈  𝐴 )  ∧  ( 𝑆  ∈  𝐴  ∧  𝑇  ∈  𝐴  ∧  𝑈  ∈  𝐴 ) )  ∧  ( 𝑌  ∈  𝑂  ∧  𝑍  ∈  𝑂 )  ∧  ( ( ¬  𝐶  ≤  ( 𝑃  ∨  𝑄 )  ∧  ¬  𝐶  ≤  ( 𝑄  ∨  𝑅 )  ∧  ¬  𝐶  ≤  ( 𝑅  ∨  𝑃 ) )  ∧  ( ¬  𝐶  ≤  ( 𝑆  ∨  𝑇 )  ∧  ¬  𝐶  ≤  ( 𝑇  ∨  𝑈 )  ∧  ¬  𝐶  ≤  ( 𝑈  ∨  𝑆 ) )  ∧  ( 𝐶  ≤  ( 𝑃  ∨  𝑆 )  ∧  𝐶  ≤  ( 𝑄  ∨  𝑇 )  ∧  𝐶  ≤  ( 𝑅  ∨  𝑈 ) ) ) ) )  | 
						
						
							| 2 | 
							
								
							 | 
							dalem.l | 
							⊢  ≤   =  ( le ‘ 𝐾 )  | 
						
						
							| 3 | 
							
								
							 | 
							dalem.j | 
							⊢  ∨   =  ( join ‘ 𝐾 )  | 
						
						
							| 4 | 
							
								
							 | 
							dalem.a | 
							⊢ 𝐴  =  ( Atoms ‘ 𝐾 )  | 
						
						
							| 5 | 
							
								
							 | 
							dalem.ps | 
							⊢ ( 𝜓  ↔  ( ( 𝑐  ∈  𝐴  ∧  𝑑  ∈  𝐴 )  ∧  ¬  𝑐  ≤  𝑌  ∧  ( 𝑑  ≠  𝑐  ∧  ¬  𝑑  ≤  𝑌  ∧  𝐶  ≤  ( 𝑐  ∨  𝑑 ) ) ) )  | 
						
						
							| 6 | 
							
								
							 | 
							dalem38.m | 
							⊢  ∧   =  ( meet ‘ 𝐾 )  | 
						
						
							| 7 | 
							
								
							 | 
							dalem38.o | 
							⊢ 𝑂  =  ( LPlanes ‘ 𝐾 )  | 
						
						
							| 8 | 
							
								
							 | 
							dalem38.y | 
							⊢ 𝑌  =  ( ( 𝑃  ∨  𝑄 )  ∨  𝑅 )  | 
						
						
							| 9 | 
							
								
							 | 
							dalem38.z | 
							⊢ 𝑍  =  ( ( 𝑆  ∨  𝑇 )  ∨  𝑈 )  | 
						
						
							| 10 | 
							
								
							 | 
							dalem38.g | 
							⊢ 𝐺  =  ( ( 𝑐  ∨  𝑃 )  ∧  ( 𝑑  ∨  𝑆 ) )  | 
						
						
							| 11 | 
							
								
							 | 
							dalem38.h | 
							⊢ 𝐻  =  ( ( 𝑐  ∨  𝑄 )  ∧  ( 𝑑  ∨  𝑇 ) )  | 
						
						
							| 12 | 
							
								
							 | 
							dalem38.i | 
							⊢ 𝐼  =  ( ( 𝑐  ∨  𝑅 )  ∧  ( 𝑑  ∨  𝑈 ) )  | 
						
						
							| 13 | 
							
								1
							 | 
							dalemkehl | 
							⊢ ( 𝜑  →  𝐾  ∈  HL )  | 
						
						
							| 14 | 
							
								13
							 | 
							3ad2ant1 | 
							⊢ ( ( 𝜑  ∧  𝑌  =  𝑍  ∧  𝜓 )  →  𝐾  ∈  HL )  | 
						
						
							| 15 | 
							
								1 2 3 4 5 6 7 8 9 10
							 | 
							dalem23 | 
							⊢ ( ( 𝜑  ∧  𝑌  =  𝑍  ∧  𝜓 )  →  𝐺  ∈  𝐴 )  | 
						
						
							| 16 | 
							
								1 2 3 4 5 6 7 8 9 11
							 | 
							dalem29 | 
							⊢ ( ( 𝜑  ∧  𝑌  =  𝑍  ∧  𝜓 )  →  𝐻  ∈  𝐴 )  | 
						
						
							| 17 | 
							
								1 2 3 4 5 6 7 8 9 12
							 | 
							dalem34 | 
							⊢ ( ( 𝜑  ∧  𝑌  =  𝑍  ∧  𝜓 )  →  𝐼  ∈  𝐴 )  | 
						
						
							| 18 | 
							
								1 2 3 4 5 6 7 8 9 10 11 12
							 | 
							dalem41 | 
							⊢ ( ( 𝜑  ∧  𝑌  =  𝑍  ∧  𝜓 )  →  𝐺  ≠  𝐻 )  | 
						
						
							| 19 | 
							
								1 2 3 4 5 6 7 8 9 10 11 12
							 | 
							dalem40 | 
							⊢ ( ( 𝜑  ∧  𝑌  =  𝑍  ∧  𝜓 )  →  ¬  𝐼  ≤  ( 𝐺  ∨  𝐻 ) )  | 
						
						
							| 20 | 
							
								2 3 4 7
							 | 
							lplni2 | 
							⊢ ( ( 𝐾  ∈  HL  ∧  ( 𝐺  ∈  𝐴  ∧  𝐻  ∈  𝐴  ∧  𝐼  ∈  𝐴 )  ∧  ( 𝐺  ≠  𝐻  ∧  ¬  𝐼  ≤  ( 𝐺  ∨  𝐻 ) ) )  →  ( ( 𝐺  ∨  𝐻 )  ∨  𝐼 )  ∈  𝑂 )  | 
						
						
							| 21 | 
							
								14 15 16 17 18 19 20
							 | 
							syl132anc | 
							⊢ ( ( 𝜑  ∧  𝑌  =  𝑍  ∧  𝜓 )  →  ( ( 𝐺  ∨  𝐻 )  ∨  𝐼 )  ∈  𝑂 )  |