| 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 | 
							
								
							 | 
							dalem23.m | 
							 |-  ./\ = ( meet ` K )  | 
						
						
							| 7 | 
							
								
							 | 
							dalem23.o | 
							 |-  O = ( LPlanes ` K )  | 
						
						
							| 8 | 
							
								
							 | 
							dalem23.y | 
							 |-  Y = ( ( P .\/ Q ) .\/ R )  | 
						
						
							| 9 | 
							
								
							 | 
							dalem23.z | 
							 |-  Z = ( ( S .\/ T ) .\/ U )  | 
						
						
							| 10 | 
							
								
							 | 
							dalem23.g | 
							 |-  G = ( ( c .\/ P ) ./\ ( d .\/ S ) )  | 
						
						
							| 11 | 
							
								10
							 | 
							oveq1i | 
							 |-  ( G ./\ Y ) = ( ( ( c .\/ P ) ./\ ( d .\/ S ) ) ./\ Y )  | 
						
						
							| 12 | 
							
								1
							 | 
							dalemkehl | 
							 |-  ( ph -> K e. HL )  | 
						
						
							| 13 | 
							
								
							 | 
							hlol | 
							 |-  ( K e. HL -> K e. OL )  | 
						
						
							| 14 | 
							
								12 13
							 | 
							syl | 
							 |-  ( ph -> K e. OL )  | 
						
						
							| 15 | 
							
								14
							 | 
							3ad2ant1 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> K e. OL )  | 
						
						
							| 16 | 
							
								12
							 | 
							3ad2ant1 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> K e. HL )  | 
						
						
							| 17 | 
							
								5
							 | 
							dalemccea | 
							 |-  ( ps -> c e. A )  | 
						
						
							| 18 | 
							
								17
							 | 
							3ad2ant3 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> c e. A )  | 
						
						
							| 19 | 
							
								1
							 | 
							dalempea | 
							 |-  ( ph -> P e. A )  | 
						
						
							| 20 | 
							
								19
							 | 
							3ad2ant1 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> P e. A )  | 
						
						
							| 21 | 
							
								
							 | 
							eqid | 
							 |-  ( Base ` K ) = ( Base ` K )  | 
						
						
							| 22 | 
							
								21 3 4
							 | 
							hlatjcl | 
							 |-  ( ( K e. HL /\ c e. A /\ P e. A ) -> ( c .\/ P ) e. ( Base ` K ) )  | 
						
						
							| 23 | 
							
								16 18 20 22
							 | 
							syl3anc | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( c .\/ P ) e. ( Base ` K ) )  | 
						
						
							| 24 | 
							
								5
							 | 
							dalemddea | 
							 |-  ( ps -> d e. A )  | 
						
						
							| 25 | 
							
								24
							 | 
							3ad2ant3 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> d e. A )  | 
						
						
							| 26 | 
							
								1
							 | 
							dalemsea | 
							 |-  ( ph -> S e. A )  | 
						
						
							| 27 | 
							
								26
							 | 
							3ad2ant1 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> S e. A )  | 
						
						
							| 28 | 
							
								21 3 4
							 | 
							hlatjcl | 
							 |-  ( ( K e. HL /\ d e. A /\ S e. A ) -> ( d .\/ S ) e. ( Base ` K ) )  | 
						
						
							| 29 | 
							
								16 25 27 28
							 | 
							syl3anc | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( d .\/ S ) e. ( Base ` K ) )  | 
						
						
							| 30 | 
							
								1 7
							 | 
							dalemyeb | 
							 |-  ( ph -> Y e. ( Base ` K ) )  | 
						
						
							| 31 | 
							
								30
							 | 
							3ad2ant1 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> Y e. ( Base ` K ) )  | 
						
						
							| 32 | 
							
								21 6
							 | 
							latmmdir | 
							 |-  ( ( K e. OL /\ ( ( c .\/ P ) e. ( Base ` K ) /\ ( d .\/ S ) e. ( Base ` K ) /\ Y e. ( Base ` K ) ) ) -> ( ( ( c .\/ P ) ./\ ( d .\/ S ) ) ./\ Y ) = ( ( ( c .\/ P ) ./\ Y ) ./\ ( ( d .\/ S ) ./\ Y ) ) )  | 
						
						
							| 33 | 
							
								15 23 29 31 32
							 | 
							syl13anc | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( ( ( c .\/ P ) ./\ ( d .\/ S ) ) ./\ Y ) = ( ( ( c .\/ P ) ./\ Y ) ./\ ( ( d .\/ S ) ./\ Y ) ) )  | 
						
						
							| 34 | 
							
								11 33
							 | 
							eqtrid | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( G ./\ Y ) = ( ( ( c .\/ P ) ./\ Y ) ./\ ( ( d .\/ S ) ./\ Y ) ) )  | 
						
						
							| 35 | 
							
								3 4
							 | 
							hlatjcom | 
							 |-  ( ( K e. HL /\ c e. A /\ P e. A ) -> ( c .\/ P ) = ( P .\/ c ) )  | 
						
						
							| 36 | 
							
								16 18 20 35
							 | 
							syl3anc | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( c .\/ P ) = ( P .\/ c ) )  | 
						
						
							| 37 | 
							
								36
							 | 
							oveq1d | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( ( c .\/ P ) ./\ Y ) = ( ( P .\/ c ) ./\ Y ) )  | 
						
						
							| 38 | 
							
								1 2 3 4 7 8
							 | 
							dalemply | 
							 |-  ( ph -> P .<_ Y )  | 
						
						
							| 39 | 
							
								38
							 | 
							3ad2ant1 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> P .<_ Y )  | 
						
						
							| 40 | 
							
								5
							 | 
							dalem-ccly | 
							 |-  ( ps -> -. c .<_ Y )  | 
						
						
							| 41 | 
							
								40
							 | 
							3ad2ant3 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> -. c .<_ Y )  | 
						
						
							| 42 | 
							
								21 2 3 6 4
							 | 
							2atjm | 
							 |-  ( ( K e. HL /\ ( P e. A /\ c e. A /\ Y e. ( Base ` K ) ) /\ ( P .<_ Y /\ -. c .<_ Y ) ) -> ( ( P .\/ c ) ./\ Y ) = P )  | 
						
						
							| 43 | 
							
								16 20 18 31 39 41 42
							 | 
							syl132anc | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( ( P .\/ c ) ./\ Y ) = P )  | 
						
						
							| 44 | 
							
								37 43
							 | 
							eqtrd | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( ( c .\/ P ) ./\ Y ) = P )  | 
						
						
							| 45 | 
							
								3 4
							 | 
							hlatjcom | 
							 |-  ( ( K e. HL /\ d e. A /\ S e. A ) -> ( d .\/ S ) = ( S .\/ d ) )  | 
						
						
							| 46 | 
							
								16 25 27 45
							 | 
							syl3anc | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( d .\/ S ) = ( S .\/ d ) )  | 
						
						
							| 47 | 
							
								46
							 | 
							oveq1d | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( ( d .\/ S ) ./\ Y ) = ( ( S .\/ d ) ./\ Y ) )  | 
						
						
							| 48 | 
							
								1 2 3 4 9
							 | 
							dalemsly | 
							 |-  ( ( ph /\ Y = Z ) -> S .<_ Y )  | 
						
						
							| 49 | 
							
								48
							 | 
							3adant3 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> S .<_ Y )  | 
						
						
							| 50 | 
							
								5
							 | 
							dalem-ddly | 
							 |-  ( ps -> -. d .<_ Y )  | 
						
						
							| 51 | 
							
								50
							 | 
							3ad2ant3 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> -. d .<_ Y )  | 
						
						
							| 52 | 
							
								21 2 3 6 4
							 | 
							2atjm | 
							 |-  ( ( K e. HL /\ ( S e. A /\ d e. A /\ Y e. ( Base ` K ) ) /\ ( S .<_ Y /\ -. d .<_ Y ) ) -> ( ( S .\/ d ) ./\ Y ) = S )  | 
						
						
							| 53 | 
							
								16 27 25 31 49 51 52
							 | 
							syl132anc | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( ( S .\/ d ) ./\ Y ) = S )  | 
						
						
							| 54 | 
							
								47 53
							 | 
							eqtrd | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( ( d .\/ S ) ./\ Y ) = S )  | 
						
						
							| 55 | 
							
								44 54
							 | 
							oveq12d | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( ( ( c .\/ P ) ./\ Y ) ./\ ( ( d .\/ S ) ./\ Y ) ) = ( P ./\ S ) )  | 
						
						
							| 56 | 
							
								1 2 3 4 7 8
							 | 
							dalempnes | 
							 |-  ( ph -> P =/= S )  | 
						
						
							| 57 | 
							
								
							 | 
							hlatl | 
							 |-  ( K e. HL -> K e. AtLat )  | 
						
						
							| 58 | 
							
								12 57
							 | 
							syl | 
							 |-  ( ph -> K e. AtLat )  | 
						
						
							| 59 | 
							
								
							 | 
							eqid | 
							 |-  ( 0. ` K ) = ( 0. ` K )  | 
						
						
							| 60 | 
							
								6 59 4
							 | 
							atnem0 | 
							 |-  ( ( K e. AtLat /\ P e. A /\ S e. A ) -> ( P =/= S <-> ( P ./\ S ) = ( 0. ` K ) ) )  | 
						
						
							| 61 | 
							
								58 19 26 60
							 | 
							syl3anc | 
							 |-  ( ph -> ( P =/= S <-> ( P ./\ S ) = ( 0. ` K ) ) )  | 
						
						
							| 62 | 
							
								56 61
							 | 
							mpbid | 
							 |-  ( ph -> ( P ./\ S ) = ( 0. ` K ) )  | 
						
						
							| 63 | 
							
								62
							 | 
							3ad2ant1 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( P ./\ S ) = ( 0. ` K ) )  | 
						
						
							| 64 | 
							
								34 55 63
							 | 
							3eqtrd | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( G ./\ Y ) = ( 0. ` K ) )  | 
						
						
							| 65 | 
							
								58
							 | 
							3ad2ant1 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> K e. AtLat )  | 
						
						
							| 66 | 
							
								1 2 3 4 5 6 7 8 9 10
							 | 
							dalem23 | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> G e. A )  | 
						
						
							| 67 | 
							
								21 2 6 59 4
							 | 
							atnle | 
							 |-  ( ( K e. AtLat /\ G e. A /\ Y e. ( Base ` K ) ) -> ( -. G .<_ Y <-> ( G ./\ Y ) = ( 0. ` K ) ) )  | 
						
						
							| 68 | 
							
								65 66 31 67
							 | 
							syl3anc | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> ( -. G .<_ Y <-> ( G ./\ Y ) = ( 0. ` K ) ) )  | 
						
						
							| 69 | 
							
								64 68
							 | 
							mpbird | 
							 |-  ( ( ph /\ Y = Z /\ ps ) -> -. G .<_ Y )  |