| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							dalema.ph | 
							 |-  ( ph <-> ( ( ( K e. HL /\ C e. ( Base ` K ) ) /\ ( P e. A /\ Q e. A /\ R e. A ) /\ ( S e. A /\ T e. A /\ U e. A ) ) /\ ( Y e. O /\ Z e. 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 | 
							
								
							 | 
							dalemc.l | 
							 |-  .<_ = ( le ` K )  | 
						
						
							| 3 | 
							
								
							 | 
							dalemc.j | 
							 |-  .\/ = ( join ` K )  | 
						
						
							| 4 | 
							
								
							 | 
							dalemc.a | 
							 |-  A = ( Atoms ` K )  | 
						
						
							| 5 | 
							
								
							 | 
							dalempnes.o | 
							 |-  O = ( LPlanes ` K )  | 
						
						
							| 6 | 
							
								
							 | 
							dalempnes.y | 
							 |-  Y = ( ( P .\/ Q ) .\/ R )  | 
						
						
							| 7 | 
							
								1
							 | 
							dalemkelat | 
							 |-  ( ph -> K e. Lat )  | 
						
						
							| 8 | 
							
								1 4
							 | 
							dalemceb | 
							 |-  ( ph -> C e. ( Base ` K ) )  | 
						
						
							| 9 | 
							
								1 4
							 | 
							dalemseb | 
							 |-  ( ph -> S e. ( Base ` K ) )  | 
						
						
							| 10 | 
							
								1 4
							 | 
							dalemteb | 
							 |-  ( ph -> T e. ( Base ` K ) )  | 
						
						
							| 11 | 
							
								
							 | 
							simp321 | 
							 |-  ( ( ( ( K e. HL /\ C e. ( Base ` K ) ) /\ ( P e. A /\ Q e. A /\ R e. A ) /\ ( S e. A /\ T e. A /\ U e. A ) ) /\ ( Y e. O /\ Z e. 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 ) ) ) ) -> -. C .<_ ( S .\/ T ) )  | 
						
						
							| 12 | 
							
								1 11
							 | 
							sylbi | 
							 |-  ( ph -> -. C .<_ ( S .\/ T ) )  | 
						
						
							| 13 | 
							
								
							 | 
							eqid | 
							 |-  ( Base ` K ) = ( Base ` K )  | 
						
						
							| 14 | 
							
								13 2 3
							 | 
							latnlej2l | 
							 |-  ( ( K e. Lat /\ ( C e. ( Base ` K ) /\ S e. ( Base ` K ) /\ T e. ( Base ` K ) ) /\ -. C .<_ ( S .\/ T ) ) -> -. C .<_ S )  | 
						
						
							| 15 | 
							
								7 8 9 10 12 14
							 | 
							syl131anc | 
							 |-  ( ph -> -. C .<_ S )  | 
						
						
							| 16 | 
							
								1
							 | 
							dalemclpjs | 
							 |-  ( ph -> C .<_ ( P .\/ S ) )  | 
						
						
							| 17 | 
							
								
							 | 
							oveq1 | 
							 |-  ( P = S -> ( P .\/ S ) = ( S .\/ S ) )  | 
						
						
							| 18 | 
							
								17
							 | 
							breq2d | 
							 |-  ( P = S -> ( C .<_ ( P .\/ S ) <-> C .<_ ( S .\/ S ) ) )  | 
						
						
							| 19 | 
							
								16 18
							 | 
							syl5ibcom | 
							 |-  ( ph -> ( P = S -> C .<_ ( S .\/ S ) ) )  | 
						
						
							| 20 | 
							
								1
							 | 
							dalemkehl | 
							 |-  ( ph -> K e. HL )  | 
						
						
							| 21 | 
							
								1
							 | 
							dalemsea | 
							 |-  ( ph -> S e. A )  | 
						
						
							| 22 | 
							
								3 4
							 | 
							hlatjidm | 
							 |-  ( ( K e. HL /\ S e. A ) -> ( S .\/ S ) = S )  | 
						
						
							| 23 | 
							
								20 21 22
							 | 
							syl2anc | 
							 |-  ( ph -> ( S .\/ S ) = S )  | 
						
						
							| 24 | 
							
								23
							 | 
							breq2d | 
							 |-  ( ph -> ( C .<_ ( S .\/ S ) <-> C .<_ S ) )  | 
						
						
							| 25 | 
							
								19 24
							 | 
							sylibd | 
							 |-  ( ph -> ( P = S -> C .<_ S ) )  | 
						
						
							| 26 | 
							
								25
							 | 
							necon3bd | 
							 |-  ( ph -> ( -. C .<_ S -> P =/= S ) )  | 
						
						
							| 27 | 
							
								15 26
							 | 
							mpd | 
							 |-  ( ph -> P =/= S )  |