| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							cdlemefr27.b | 
							 |-  B = ( Base ` K )  | 
						
						
							| 2 | 
							
								
							 | 
							cdlemefr27.l | 
							 |-  .<_ = ( le ` K )  | 
						
						
							| 3 | 
							
								
							 | 
							cdlemefr27.j | 
							 |-  .\/ = ( join ` K )  | 
						
						
							| 4 | 
							
								
							 | 
							cdlemefr27.m | 
							 |-  ./\ = ( meet ` K )  | 
						
						
							| 5 | 
							
								
							 | 
							cdlemefr27.a | 
							 |-  A = ( Atoms ` K )  | 
						
						
							| 6 | 
							
								
							 | 
							cdlemefr27.h | 
							 |-  H = ( LHyp ` K )  | 
						
						
							| 7 | 
							
								
							 | 
							cdlemefr27.u | 
							 |-  U = ( ( P .\/ Q ) ./\ W )  | 
						
						
							| 8 | 
							
								
							 | 
							cdlemefr27.c | 
							 |-  C = ( ( s .\/ U ) ./\ ( Q .\/ ( ( P .\/ s ) ./\ W ) ) )  | 
						
						
							| 9 | 
							
								
							 | 
							cdlemefr27.n | 
							 |-  N = if ( s .<_ ( P .\/ Q ) , I , C )  | 
						
						
							| 10 | 
							
								1 2 3 4 5 6 7 8 9
							 | 
							cdlemefr32sn2aw | 
							 |-  ( ( ( ( K e. HL /\ W e. H ) /\ ( P e. A /\ -. P .<_ W ) /\ ( Q e. A /\ -. Q .<_ W ) ) /\ ( P =/= Q /\ ( R e. A /\ -. R .<_ W ) ) /\ -. R .<_ ( P .\/ Q ) ) -> ( [_ R / s ]_ N e. A /\ -. [_ R / s ]_ N .<_ W ) )  | 
						
						
							| 11 | 
							
								10
							 | 
							simpld | 
							 |-  ( ( ( ( K e. HL /\ W e. H ) /\ ( P e. A /\ -. P .<_ W ) /\ ( Q e. A /\ -. Q .<_ W ) ) /\ ( P =/= Q /\ ( R e. A /\ -. R .<_ W ) ) /\ -. R .<_ ( P .\/ Q ) ) -> [_ R / s ]_ N e. A )  | 
						
						
							| 12 | 
							
								1 5
							 | 
							atbase | 
							 |-  ( [_ R / s ]_ N e. A -> [_ R / s ]_ N e. B )  | 
						
						
							| 13 | 
							
								11 12
							 | 
							syl | 
							 |-  ( ( ( ( K e. HL /\ W e. H ) /\ ( P e. A /\ -. P .<_ W ) /\ ( Q e. A /\ -. Q .<_ W ) ) /\ ( P =/= Q /\ ( R e. A /\ -. R .<_ W ) ) /\ -. R .<_ ( P .\/ Q ) ) -> [_ R / s ]_ N e. B )  |