| 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 | 
							
								1
							 | 
							4atexlemnslpq | 
							 |-  ( ph -> -. S .<_ ( P .\/ Q ) )  | 
						
						
							| 10 | 
							
								1
							 | 
							4atexlemk | 
							 |-  ( ph -> K e. HL )  | 
						
						
							| 11 | 
							
								1
							 | 
							4atexlemp | 
							 |-  ( ph -> P e. A )  | 
						
						
							| 12 | 
							
								1
							 | 
							4atexlems | 
							 |-  ( ph -> S e. A )  | 
						
						
							| 13 | 
							
								2 3 5
							 | 
							hlatlej2 | 
							 |-  ( ( K e. HL /\ P e. A /\ S e. A ) -> S .<_ ( P .\/ S ) )  | 
						
						
							| 14 | 
							
								10 11 12 13
							 | 
							syl3anc | 
							 |-  ( ph -> S .<_ ( P .\/ S ) )  | 
						
						
							| 15 | 
							
								14
							 | 
							adantr | 
							 |-  ( ( ph /\ U = V ) -> S .<_ ( P .\/ S ) )  | 
						
						
							| 16 | 
							
								1
							 | 
							4atexlemkl | 
							 |-  ( ph -> K e. Lat )  | 
						
						
							| 17 | 
							
								1 3 5
							 | 
							4atexlempsb | 
							 |-  ( ph -> ( P .\/ S ) e. ( Base ` K ) )  | 
						
						
							| 18 | 
							
								1 6
							 | 
							4atexlemwb | 
							 |-  ( ph -> W e. ( Base ` K ) )  | 
						
						
							| 19 | 
							
								
							 | 
							eqid | 
							 |-  ( Base ` K ) = ( Base ` K )  | 
						
						
							| 20 | 
							
								19 2 4
							 | 
							latmle1 | 
							 |-  ( ( K e. Lat /\ ( P .\/ S ) e. ( Base ` K ) /\ W e. ( Base ` K ) ) -> ( ( P .\/ S ) ./\ W ) .<_ ( P .\/ S ) )  | 
						
						
							| 21 | 
							
								16 17 18 20
							 | 
							syl3anc | 
							 |-  ( ph -> ( ( P .\/ S ) ./\ W ) .<_ ( P .\/ S ) )  | 
						
						
							| 22 | 
							
								8 21
							 | 
							eqbrtrid | 
							 |-  ( ph -> V .<_ ( P .\/ S ) )  | 
						
						
							| 23 | 
							
								1
							 | 
							4atexlemkc | 
							 |-  ( ph -> K e. CvLat )  | 
						
						
							| 24 | 
							
								1 2 3 4 5 6 7 8
							 | 
							4atexlemv | 
							 |-  ( ph -> V e. A )  | 
						
						
							| 25 | 
							
								19 2 4
							 | 
							latmle2 | 
							 |-  ( ( K e. Lat /\ ( P .\/ S ) e. ( Base ` K ) /\ W e. ( Base ` K ) ) -> ( ( P .\/ S ) ./\ W ) .<_ W )  | 
						
						
							| 26 | 
							
								16 17 18 25
							 | 
							syl3anc | 
							 |-  ( ph -> ( ( P .\/ S ) ./\ W ) .<_ W )  | 
						
						
							| 27 | 
							
								8 26
							 | 
							eqbrtrid | 
							 |-  ( ph -> V .<_ W )  | 
						
						
							| 28 | 
							
								1
							 | 
							4atexlempw | 
							 |-  ( ph -> ( P e. A /\ -. P .<_ W ) )  | 
						
						
							| 29 | 
							
								28
							 | 
							simprd | 
							 |-  ( ph -> -. P .<_ W )  | 
						
						
							| 30 | 
							
								
							 | 
							nbrne2 | 
							 |-  ( ( V .<_ W /\ -. P .<_ W ) -> V =/= P )  | 
						
						
							| 31 | 
							
								27 29 30
							 | 
							syl2anc | 
							 |-  ( ph -> V =/= P )  | 
						
						
							| 32 | 
							
								2 3 5
							 | 
							cvlatexchb1 | 
							 |-  ( ( K e. CvLat /\ ( V e. A /\ S e. A /\ P e. A ) /\ V =/= P ) -> ( V .<_ ( P .\/ S ) <-> ( P .\/ V ) = ( P .\/ S ) ) )  | 
						
						
							| 33 | 
							
								23 24 12 11 31 32
							 | 
							syl131anc | 
							 |-  ( ph -> ( V .<_ ( P .\/ S ) <-> ( P .\/ V ) = ( P .\/ S ) ) )  | 
						
						
							| 34 | 
							
								22 33
							 | 
							mpbid | 
							 |-  ( ph -> ( P .\/ V ) = ( P .\/ S ) )  | 
						
						
							| 35 | 
							
								34
							 | 
							adantr | 
							 |-  ( ( ph /\ U = V ) -> ( P .\/ V ) = ( P .\/ S ) )  | 
						
						
							| 36 | 
							
								
							 | 
							oveq2 | 
							 |-  ( U = V -> ( P .\/ U ) = ( P .\/ V ) )  | 
						
						
							| 37 | 
							
								36
							 | 
							eqcomd | 
							 |-  ( U = V -> ( P .\/ V ) = ( P .\/ U ) )  | 
						
						
							| 38 | 
							
								1
							 | 
							4atexlemq | 
							 |-  ( ph -> Q e. A )  | 
						
						
							| 39 | 
							
								19 3 5
							 | 
							hlatjcl | 
							 |-  ( ( K e. HL /\ P e. A /\ Q e. A ) -> ( P .\/ Q ) e. ( Base ` K ) )  | 
						
						
							| 40 | 
							
								10 11 38 39
							 | 
							syl3anc | 
							 |-  ( ph -> ( P .\/ Q ) e. ( Base ` K ) )  | 
						
						
							| 41 | 
							
								19 2 4
							 | 
							latmle1 | 
							 |-  ( ( K e. Lat /\ ( P .\/ Q ) e. ( Base ` K ) /\ W e. ( Base ` K ) ) -> ( ( P .\/ Q ) ./\ W ) .<_ ( P .\/ Q ) )  | 
						
						
							| 42 | 
							
								16 40 18 41
							 | 
							syl3anc | 
							 |-  ( ph -> ( ( P .\/ Q ) ./\ W ) .<_ ( P .\/ Q ) )  | 
						
						
							| 43 | 
							
								7 42
							 | 
							eqbrtrid | 
							 |-  ( ph -> U .<_ ( P .\/ Q ) )  | 
						
						
							| 44 | 
							
								1 2 3 4 5 6 7
							 | 
							4atexlemu | 
							 |-  ( ph -> U e. A )  | 
						
						
							| 45 | 
							
								19 2 4
							 | 
							latmle2 | 
							 |-  ( ( K e. Lat /\ ( P .\/ Q ) e. ( Base ` K ) /\ W e. ( Base ` K ) ) -> ( ( P .\/ Q ) ./\ W ) .<_ W )  | 
						
						
							| 46 | 
							
								16 40 18 45
							 | 
							syl3anc | 
							 |-  ( ph -> ( ( P .\/ Q ) ./\ W ) .<_ W )  | 
						
						
							| 47 | 
							
								7 46
							 | 
							eqbrtrid | 
							 |-  ( ph -> U .<_ W )  | 
						
						
							| 48 | 
							
								
							 | 
							nbrne2 | 
							 |-  ( ( U .<_ W /\ -. P .<_ W ) -> U =/= P )  | 
						
						
							| 49 | 
							
								47 29 48
							 | 
							syl2anc | 
							 |-  ( ph -> U =/= P )  | 
						
						
							| 50 | 
							
								2 3 5
							 | 
							cvlatexchb1 | 
							 |-  ( ( K e. CvLat /\ ( U e. A /\ Q e. A /\ P e. A ) /\ U =/= P ) -> ( U .<_ ( P .\/ Q ) <-> ( P .\/ U ) = ( P .\/ Q ) ) )  | 
						
						
							| 51 | 
							
								23 44 38 11 49 50
							 | 
							syl131anc | 
							 |-  ( ph -> ( U .<_ ( P .\/ Q ) <-> ( P .\/ U ) = ( P .\/ Q ) ) )  | 
						
						
							| 52 | 
							
								43 51
							 | 
							mpbid | 
							 |-  ( ph -> ( P .\/ U ) = ( P .\/ Q ) )  | 
						
						
							| 53 | 
							
								37 52
							 | 
							sylan9eqr | 
							 |-  ( ( ph /\ U = V ) -> ( P .\/ V ) = ( P .\/ Q ) )  | 
						
						
							| 54 | 
							
								35 53
							 | 
							eqtr3d | 
							 |-  ( ( ph /\ U = V ) -> ( P .\/ S ) = ( P .\/ Q ) )  | 
						
						
							| 55 | 
							
								15 54
							 | 
							breqtrd | 
							 |-  ( ( ph /\ U = V ) -> S .<_ ( P .\/ Q ) )  | 
						
						
							| 56 | 
							
								55
							 | 
							ex | 
							 |-  ( ph -> ( U = V -> S .<_ ( P .\/ Q ) ) )  | 
						
						
							| 57 | 
							
								56
							 | 
							necon3bd | 
							 |-  ( ph -> ( -. S .<_ ( P .\/ Q ) -> U =/= V ) )  | 
						
						
							| 58 | 
							
								9 57
							 | 
							mpd | 
							 |-  ( ph -> U =/= V )  |