| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							dalem.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 | 
							
								
							 | 
							dalem.l | 
							 |-  .<_ = ( le ` K )  | 
						
						
							| 3 | 
							
								
							 | 
							dalem.j | 
							 |-  .\/ = ( join ` K )  | 
						
						
							| 4 | 
							
								
							 | 
							dalem.a | 
							 |-  A = ( Atoms ` K )  | 
						
						
							| 5 | 
							
								
							 | 
							dalem.ps | 
							 |-  ( ps <-> ( ( c e. A /\ d e. A ) /\ -. c .<_ Y /\ ( d =/= c /\ -. d .<_ Y /\ C .<_ ( c .\/ d ) ) ) )  | 
						
						
							| 6 | 
							
								
							 | 
							dalem44.m | 
							 |-  ./\ = ( meet ` K )  | 
						
						
							| 7 | 
							
								
							 | 
							dalem44.o | 
							 |-  O = ( LPlanes ` K )  | 
						
						
							| 8 | 
							
								
							 | 
							dalem44.y | 
							 |-  Y = ( ( P .\/ Q ) .\/ R )  | 
						
						
							| 9 | 
							
								
							 | 
							dalem44.z | 
							 |-  Z = ( ( S .\/ T ) .\/ U )  | 
						
						
							| 10 | 
							
								
							 | 
							dalem44.g | 
							 |-  G = ( ( c .\/ P ) ./\ ( d .\/ S ) )  | 
						
						
							| 11 | 
							
								
							 | 
							dalem44.h | 
							 |-  H = ( ( c .\/ Q ) ./\ ( d .\/ T ) )  | 
						
						
							| 12 | 
							
								
							 | 
							dalem44.i | 
							 |-  I = ( ( c .\/ R ) ./\ ( d .\/ U ) )  | 
						
						
							| 13 | 
							
								1
							 | 
							dalemkelat | 
							 |-  ( ph -> K e. Lat )  | 
						
						
							| 14 | 
							
								13
							 | 
							adantr | 
							 |-  ( ( ph /\ ps ) -> K e. Lat )  | 
						
						
							| 15 | 
							
								5 4
							 | 
							dalemcceb | 
							 |-  ( ps -> c e. ( Base ` K ) )  | 
						
						
							| 16 | 
							
								15
							 | 
							adantl | 
							 |-  ( ( ph /\ ps ) -> c e. ( Base ` K ) )  | 
						
						
							| 17 | 
							
								1 3 4
							 | 
							dalempjqeb | 
							 |-  ( ph -> ( P .\/ Q ) e. ( Base ` K ) )  | 
						
						
							| 18 | 
							
								17
							 | 
							adantr | 
							 |-  ( ( ph /\ ps ) -> ( P .\/ Q ) e. ( Base ` K ) )  | 
						
						
							| 19 | 
							
								1 4
							 | 
							dalemreb | 
							 |-  ( ph -> R e. ( Base ` K ) )  | 
						
						
							| 20 | 
							
								19
							 | 
							adantr | 
							 |-  ( ( ph /\ ps ) -> R e. ( Base ` K ) )  | 
						
						
							| 21 | 
							
								5
							 | 
							dalem-ccly | 
							 |-  ( ps -> -. c .<_ Y )  | 
						
						
							| 22 | 
							
								8
							 | 
							breq2i | 
							 |-  ( c .<_ Y <-> c .<_ ( ( P .\/ Q ) .\/ R ) )  | 
						
						
							| 23 | 
							
								21 22
							 | 
							sylnib | 
							 |-  ( ps -> -. c .<_ ( ( P .\/ Q ) .\/ R ) )  | 
						
						
							| 24 | 
							
								23
							 | 
							adantl | 
							 |-  ( ( ph /\ ps ) -> -. c .<_ ( ( P .\/ Q ) .\/ R ) )  | 
						
						
							| 25 | 
							
								
							 | 
							eqid | 
							 |-  ( Base ` K ) = ( Base ` K )  | 
						
						
							| 26 | 
							
								25 2 3
							 | 
							latnlej2l | 
							 |-  ( ( K e. Lat /\ ( c e. ( Base ` K ) /\ ( P .\/ Q ) e. ( Base ` K ) /\ R e. ( Base ` K ) ) /\ -. c .<_ ( ( P .\/ Q ) .\/ R ) ) -> -. c .<_ ( P .\/ Q ) )  | 
						
						
							| 27 | 
							
								14 16 18 20 24 26
							 | 
							syl131anc | 
							 |-  ( ( ph /\ ps ) -> -. c .<_ ( P .\/ Q ) )  |