| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							4thatlem.ph | 
							 |-  ( ph <-> ( ( ( K e. HL /\ W e. H ) /\ ( P e. A /\ -. P .<_ W ) /\ ( Q e. A /\ -. Q .<_ W ) ) /\ ( S e. A /\ ( R e. A /\ -. R .<_ W /\ ( P .\/ R ) = ( Q .\/ R ) ) /\ ( T e. A /\ ( U .\/ T ) = ( V .\/ T ) ) ) /\ ( P =/= Q /\ -. S .<_ ( P .\/ Q ) ) ) )  | 
						
						
							| 2 | 
							
								
							 | 
							4thatlem0.l | 
							 |-  .<_ = ( le ` K )  | 
						
						
							| 3 | 
							
								
							 | 
							4thatlem0.j | 
							 |-  .\/ = ( join ` K )  | 
						
						
							| 4 | 
							
								
							 | 
							4thatlem0.m | 
							 |-  ./\ = ( meet ` K )  | 
						
						
							| 5 | 
							
								
							 | 
							4thatlem0.a | 
							 |-  A = ( Atoms ` K )  | 
						
						
							| 6 | 
							
								
							 | 
							4thatlem0.h | 
							 |-  H = ( LHyp ` K )  | 
						
						
							| 7 | 
							
								
							 | 
							4thatlem0.u | 
							 |-  U = ( ( P .\/ Q ) ./\ W )  | 
						
						
							| 8 | 
							
								
							 | 
							4thatlem0.v | 
							 |-  V = ( ( P .\/ S ) ./\ W )  | 
						
						
							| 9 | 
							
								
							 | 
							4thatlem0.c | 
							 |-  C = ( ( Q .\/ T ) ./\ ( P .\/ S ) )  | 
						
						
							| 10 | 
							
								1 2 3 4 5 6 7 8 9
							 | 
							4atexlemc | 
							 |-  ( ph -> C e. A )  | 
						
						
							| 11 | 
							
								10
							 | 
							adantr | 
							 |-  ( ( ph /\ C =/= S ) -> C e. A )  | 
						
						
							| 12 | 
							
								1 2 3 4 5 6 7 8 9
							 | 
							4atexlemnclw | 
							 |-  ( ph -> -. C .<_ W )  | 
						
						
							| 13 | 
							
								12
							 | 
							adantr | 
							 |-  ( ( ph /\ C =/= S ) -> -. C .<_ W )  | 
						
						
							| 14 | 
							
								1 2 3 4 5 6 7 8
							 | 
							4atexlemntlpq | 
							 |-  ( ph -> -. T .<_ ( P .\/ Q ) )  | 
						
						
							| 15 | 
							
								
							 | 
							id | 
							 |-  ( C = P -> C = P )  | 
						
						
							| 16 | 
							
								9 15
							 | 
							eqtr3id | 
							 |-  ( C = P -> ( ( Q .\/ T ) ./\ ( P .\/ S ) ) = P )  | 
						
						
							| 17 | 
							
								16
							 | 
							adantl | 
							 |-  ( ( ph /\ C = P ) -> ( ( Q .\/ T ) ./\ ( P .\/ S ) ) = P )  | 
						
						
							| 18 | 
							
								1
							 | 
							4atexlemkl | 
							 |-  ( ph -> K e. Lat )  | 
						
						
							| 19 | 
							
								1 3 5
							 | 
							4atexlemqtb | 
							 |-  ( ph -> ( Q .\/ T ) e. ( Base ` K ) )  | 
						
						
							| 20 | 
							
								1 3 5
							 | 
							4atexlempsb | 
							 |-  ( ph -> ( P .\/ S ) e. ( Base ` K ) )  | 
						
						
							| 21 | 
							
								
							 | 
							eqid | 
							 |-  ( Base ` K ) = ( Base ` K )  | 
						
						
							| 22 | 
							
								21 2 4
							 | 
							latmle1 | 
							 |-  ( ( K e. Lat /\ ( Q .\/ T ) e. ( Base ` K ) /\ ( P .\/ S ) e. ( Base ` K ) ) -> ( ( Q .\/ T ) ./\ ( P .\/ S ) ) .<_ ( Q .\/ T ) )  | 
						
						
							| 23 | 
							
								18 19 20 22
							 | 
							syl3anc | 
							 |-  ( ph -> ( ( Q .\/ T ) ./\ ( P .\/ S ) ) .<_ ( Q .\/ T ) )  | 
						
						
							| 24 | 
							
								1
							 | 
							4atexlemk | 
							 |-  ( ph -> K e. HL )  | 
						
						
							| 25 | 
							
								1
							 | 
							4atexlemq | 
							 |-  ( ph -> Q e. A )  | 
						
						
							| 26 | 
							
								1
							 | 
							4atexlemt | 
							 |-  ( ph -> T e. A )  | 
						
						
							| 27 | 
							
								3 5
							 | 
							hlatjcom | 
							 |-  ( ( K e. HL /\ Q e. A /\ T e. A ) -> ( Q .\/ T ) = ( T .\/ Q ) )  | 
						
						
							| 28 | 
							
								24 25 26 27
							 | 
							syl3anc | 
							 |-  ( ph -> ( Q .\/ T ) = ( T .\/ Q ) )  | 
						
						
							| 29 | 
							
								23 28
							 | 
							breqtrd | 
							 |-  ( ph -> ( ( Q .\/ T ) ./\ ( P .\/ S ) ) .<_ ( T .\/ Q ) )  | 
						
						
							| 30 | 
							
								29
							 | 
							adantr | 
							 |-  ( ( ph /\ C = P ) -> ( ( Q .\/ T ) ./\ ( P .\/ S ) ) .<_ ( T .\/ Q ) )  | 
						
						
							| 31 | 
							
								17 30
							 | 
							eqbrtrrd | 
							 |-  ( ( ph /\ C = P ) -> P .<_ ( T .\/ Q ) )  | 
						
						
							| 32 | 
							
								1
							 | 
							4atexlemkc | 
							 |-  ( ph -> K e. CvLat )  | 
						
						
							| 33 | 
							
								1
							 | 
							4atexlemp | 
							 |-  ( ph -> P e. A )  | 
						
						
							| 34 | 
							
								1
							 | 
							4atexlempnq | 
							 |-  ( ph -> P =/= Q )  | 
						
						
							| 35 | 
							
								2 3 5
							 | 
							cvlatexch2 | 
							 |-  ( ( K e. CvLat /\ ( P e. A /\ T e. A /\ Q e. A ) /\ P =/= Q ) -> ( P .<_ ( T .\/ Q ) -> T .<_ ( P .\/ Q ) ) )  | 
						
						
							| 36 | 
							
								32 33 26 25 34 35
							 | 
							syl131anc | 
							 |-  ( ph -> ( P .<_ ( T .\/ Q ) -> T .<_ ( P .\/ Q ) ) )  | 
						
						
							| 37 | 
							
								36
							 | 
							adantr | 
							 |-  ( ( ph /\ C = P ) -> ( P .<_ ( T .\/ Q ) -> T .<_ ( P .\/ Q ) ) )  | 
						
						
							| 38 | 
							
								31 37
							 | 
							mpd | 
							 |-  ( ( ph /\ C = P ) -> T .<_ ( P .\/ Q ) )  | 
						
						
							| 39 | 
							
								38
							 | 
							ex | 
							 |-  ( ph -> ( C = P -> T .<_ ( P .\/ Q ) ) )  | 
						
						
							| 40 | 
							
								39
							 | 
							necon3bd | 
							 |-  ( ph -> ( -. T .<_ ( P .\/ Q ) -> C =/= P ) )  | 
						
						
							| 41 | 
							
								14 40
							 | 
							mpd | 
							 |-  ( ph -> C =/= P )  | 
						
						
							| 42 | 
							
								41
							 | 
							adantr | 
							 |-  ( ( ph /\ C =/= S ) -> C =/= P )  | 
						
						
							| 43 | 
							
								
							 | 
							simpr | 
							 |-  ( ( ph /\ C =/= S ) -> C =/= S )  | 
						
						
							| 44 | 
							
								21 2 4
							 | 
							latmle2 | 
							 |-  ( ( K e. Lat /\ ( Q .\/ T ) e. ( Base ` K ) /\ ( P .\/ S ) e. ( Base ` K ) ) -> ( ( Q .\/ T ) ./\ ( P .\/ S ) ) .<_ ( P .\/ S ) )  | 
						
						
							| 45 | 
							
								18 19 20 44
							 | 
							syl3anc | 
							 |-  ( ph -> ( ( Q .\/ T ) ./\ ( P .\/ S ) ) .<_ ( P .\/ S ) )  | 
						
						
							| 46 | 
							
								9 45
							 | 
							eqbrtrid | 
							 |-  ( ph -> C .<_ ( P .\/ S ) )  | 
						
						
							| 47 | 
							
								46
							 | 
							adantr | 
							 |-  ( ( ph /\ C =/= S ) -> C .<_ ( P .\/ S ) )  | 
						
						
							| 48 | 
							
								1
							 | 
							4atexlems | 
							 |-  ( ph -> S e. A )  | 
						
						
							| 49 | 
							
								1 2 3 5
							 | 
							4atexlempns | 
							 |-  ( ph -> P =/= S )  | 
						
						
							| 50 | 
							
								5 2 3
							 | 
							cvlsupr2 | 
							 |-  ( ( K e. CvLat /\ ( P e. A /\ S e. A /\ C e. A ) /\ P =/= S ) -> ( ( P .\/ C ) = ( S .\/ C ) <-> ( C =/= P /\ C =/= S /\ C .<_ ( P .\/ S ) ) ) )  | 
						
						
							| 51 | 
							
								32 33 48 10 49 50
							 | 
							syl131anc | 
							 |-  ( ph -> ( ( P .\/ C ) = ( S .\/ C ) <-> ( C =/= P /\ C =/= S /\ C .<_ ( P .\/ S ) ) ) )  | 
						
						
							| 52 | 
							
								51
							 | 
							adantr | 
							 |-  ( ( ph /\ C =/= S ) -> ( ( P .\/ C ) = ( S .\/ C ) <-> ( C =/= P /\ C =/= S /\ C .<_ ( P .\/ S ) ) ) )  | 
						
						
							| 53 | 
							
								42 43 47 52
							 | 
							mpbir3and | 
							 |-  ( ( ph /\ C =/= S ) -> ( P .\/ C ) = ( S .\/ C ) )  | 
						
						
							| 54 | 
							
								
							 | 
							breq1 | 
							 |-  ( z = C -> ( z .<_ W <-> C .<_ W ) )  | 
						
						
							| 55 | 
							
								54
							 | 
							notbid | 
							 |-  ( z = C -> ( -. z .<_ W <-> -. C .<_ W ) )  | 
						
						
							| 56 | 
							
								
							 | 
							oveq2 | 
							 |-  ( z = C -> ( P .\/ z ) = ( P .\/ C ) )  | 
						
						
							| 57 | 
							
								
							 | 
							oveq2 | 
							 |-  ( z = C -> ( S .\/ z ) = ( S .\/ C ) )  | 
						
						
							| 58 | 
							
								56 57
							 | 
							eqeq12d | 
							 |-  ( z = C -> ( ( P .\/ z ) = ( S .\/ z ) <-> ( P .\/ C ) = ( S .\/ C ) ) )  | 
						
						
							| 59 | 
							
								55 58
							 | 
							anbi12d | 
							 |-  ( z = C -> ( ( -. z .<_ W /\ ( P .\/ z ) = ( S .\/ z ) ) <-> ( -. C .<_ W /\ ( P .\/ C ) = ( S .\/ C ) ) ) )  | 
						
						
							| 60 | 
							
								59
							 | 
							rspcev | 
							 |-  ( ( C e. A /\ ( -. C .<_ W /\ ( P .\/ C ) = ( S .\/ C ) ) ) -> E. z e. A ( -. z .<_ W /\ ( P .\/ z ) = ( S .\/ z ) ) )  | 
						
						
							| 61 | 
							
								11 13 53 60
							 | 
							syl12anc | 
							 |-  ( ( ph /\ C =/= S ) -> E. z e. A ( -. z .<_ W /\ ( P .\/ z ) = ( S .\/ z ) ) )  |