| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							osumcllem.l | 
							⊢  ≤   =  ( le ‘ 𝐾 )  | 
						
						
							| 2 | 
							
								
							 | 
							osumcllem.j | 
							⊢  ∨   =  ( join ‘ 𝐾 )  | 
						
						
							| 3 | 
							
								
							 | 
							osumcllem.a | 
							⊢ 𝐴  =  ( Atoms ‘ 𝐾 )  | 
						
						
							| 4 | 
							
								
							 | 
							osumcllem.p | 
							⊢  +   =  ( +𝑃 ‘ 𝐾 )  | 
						
						
							| 5 | 
							
								
							 | 
							osumcllem.o | 
							⊢  ⊥   =  ( ⊥𝑃 ‘ 𝐾 )  | 
						
						
							| 6 | 
							
								
							 | 
							osumcllem.c | 
							⊢ 𝐶  =  ( PSubCl ‘ 𝐾 )  | 
						
						
							| 7 | 
							
								
							 | 
							osumcllem.m | 
							⊢ 𝑀  =  ( 𝑋  +  { 𝑝 } )  | 
						
						
							| 8 | 
							
								
							 | 
							osumcllem.u | 
							⊢ 𝑈  =  (  ⊥  ‘ (  ⊥  ‘ ( 𝑋  +  𝑌 ) ) )  | 
						
						
							| 9 | 
							
								
							 | 
							simp11 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑋  ⊆  𝐴  ∧  𝑌  ⊆  𝐴 )  ∧  𝑝  ∈  𝐴  ∧  ( 𝑟  ∈  𝑋  ∧  𝑞  ∈  𝑌  ∧  𝑝  ≤  ( 𝑟  ∨  𝑞 ) ) )  →  𝐾  ∈  HL )  | 
						
						
							| 10 | 
							
								9
							 | 
							hllatd | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑋  ⊆  𝐴  ∧  𝑌  ⊆  𝐴 )  ∧  𝑝  ∈  𝐴  ∧  ( 𝑟  ∈  𝑋  ∧  𝑞  ∈  𝑌  ∧  𝑝  ≤  ( 𝑟  ∨  𝑞 ) ) )  →  𝐾  ∈  Lat )  | 
						
						
							| 11 | 
							
								
							 | 
							simp12 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑋  ⊆  𝐴  ∧  𝑌  ⊆  𝐴 )  ∧  𝑝  ∈  𝐴  ∧  ( 𝑟  ∈  𝑋  ∧  𝑞  ∈  𝑌  ∧  𝑝  ≤  ( 𝑟  ∨  𝑞 ) ) )  →  𝑋  ⊆  𝐴 )  | 
						
						
							| 12 | 
							
								
							 | 
							simp13 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑋  ⊆  𝐴  ∧  𝑌  ⊆  𝐴 )  ∧  𝑝  ∈  𝐴  ∧  ( 𝑟  ∈  𝑋  ∧  𝑞  ∈  𝑌  ∧  𝑝  ≤  ( 𝑟  ∨  𝑞 ) ) )  →  𝑌  ⊆  𝐴 )  | 
						
						
							| 13 | 
							
								
							 | 
							simp31 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑋  ⊆  𝐴  ∧  𝑌  ⊆  𝐴 )  ∧  𝑝  ∈  𝐴  ∧  ( 𝑟  ∈  𝑋  ∧  𝑞  ∈  𝑌  ∧  𝑝  ≤  ( 𝑟  ∨  𝑞 ) ) )  →  𝑟  ∈  𝑋 )  | 
						
						
							| 14 | 
							
								
							 | 
							simp32 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑋  ⊆  𝐴  ∧  𝑌  ⊆  𝐴 )  ∧  𝑝  ∈  𝐴  ∧  ( 𝑟  ∈  𝑋  ∧  𝑞  ∈  𝑌  ∧  𝑝  ≤  ( 𝑟  ∨  𝑞 ) ) )  →  𝑞  ∈  𝑌 )  | 
						
						
							| 15 | 
							
								
							 | 
							simp2 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑋  ⊆  𝐴  ∧  𝑌  ⊆  𝐴 )  ∧  𝑝  ∈  𝐴  ∧  ( 𝑟  ∈  𝑋  ∧  𝑞  ∈  𝑌  ∧  𝑝  ≤  ( 𝑟  ∨  𝑞 ) ) )  →  𝑝  ∈  𝐴 )  | 
						
						
							| 16 | 
							
								
							 | 
							simp33 | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑋  ⊆  𝐴  ∧  𝑌  ⊆  𝐴 )  ∧  𝑝  ∈  𝐴  ∧  ( 𝑟  ∈  𝑋  ∧  𝑞  ∈  𝑌  ∧  𝑝  ≤  ( 𝑟  ∨  𝑞 ) ) )  →  𝑝  ≤  ( 𝑟  ∨  𝑞 ) )  | 
						
						
							| 17 | 
							
								1 2 3 4
							 | 
							elpaddri | 
							⊢ ( ( ( 𝐾  ∈  Lat  ∧  𝑋  ⊆  𝐴  ∧  𝑌  ⊆  𝐴 )  ∧  ( 𝑟  ∈  𝑋  ∧  𝑞  ∈  𝑌 )  ∧  ( 𝑝  ∈  𝐴  ∧  𝑝  ≤  ( 𝑟  ∨  𝑞 ) ) )  →  𝑝  ∈  ( 𝑋  +  𝑌 ) )  | 
						
						
							| 18 | 
							
								10 11 12 13 14 15 16 17
							 | 
							syl322anc | 
							⊢ ( ( ( 𝐾  ∈  HL  ∧  𝑋  ⊆  𝐴  ∧  𝑌  ⊆  𝐴 )  ∧  𝑝  ∈  𝐴  ∧  ( 𝑟  ∈  𝑋  ∧  𝑞  ∈  𝑌  ∧  𝑝  ≤  ( 𝑟  ∨  𝑞 ) ) )  →  𝑝  ∈  ( 𝑋  +  𝑌 ) )  |