| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 2atmat.l |  |-  .<_ = ( le ` K ) | 
						
							| 2 |  | 2atmat.j |  |-  .\/ = ( join ` K ) | 
						
							| 3 |  | 2atmat.m |  |-  ./\ = ( meet ` K ) | 
						
							| 4 |  | 2atmat.a |  |-  A = ( Atoms ` K ) | 
						
							| 5 |  | simp11 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> K e. HL ) | 
						
							| 6 | 5 | hllatd |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> K e. Lat ) | 
						
							| 7 |  | eqid |  |-  ( Base ` K ) = ( Base ` K ) | 
						
							| 8 | 7 2 4 | hlatjcl |  |-  ( ( K e. HL /\ P e. A /\ Q e. A ) -> ( P .\/ Q ) e. ( Base ` K ) ) | 
						
							| 9 | 8 | 3ad2ant1 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( P .\/ Q ) e. ( Base ` K ) ) | 
						
							| 10 |  | simp21 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> R e. A ) | 
						
							| 11 | 7 4 | atbase |  |-  ( R e. A -> R e. ( Base ` K ) ) | 
						
							| 12 | 10 11 | syl |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> R e. ( Base ` K ) ) | 
						
							| 13 |  | simp22 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> S e. A ) | 
						
							| 14 | 7 4 | atbase |  |-  ( S e. A -> S e. ( Base ` K ) ) | 
						
							| 15 | 13 14 | syl |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> S e. ( Base ` K ) ) | 
						
							| 16 | 7 2 | latjass |  |-  ( ( K e. Lat /\ ( ( P .\/ Q ) e. ( Base ` K ) /\ R e. ( Base ` K ) /\ S e. ( Base ` K ) ) ) -> ( ( ( P .\/ Q ) .\/ R ) .\/ S ) = ( ( P .\/ Q ) .\/ ( R .\/ S ) ) ) | 
						
							| 17 | 6 9 12 15 16 | syl13anc |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( ( P .\/ Q ) .\/ R ) .\/ S ) = ( ( P .\/ Q ) .\/ ( R .\/ S ) ) ) | 
						
							| 18 |  | simp33 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> S .<_ ( ( P .\/ Q ) .\/ R ) ) | 
						
							| 19 | 7 2 | latjcl |  |-  ( ( K e. Lat /\ ( P .\/ Q ) e. ( Base ` K ) /\ R e. ( Base ` K ) ) -> ( ( P .\/ Q ) .\/ R ) e. ( Base ` K ) ) | 
						
							| 20 | 6 9 12 19 | syl3anc |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( P .\/ Q ) .\/ R ) e. ( Base ` K ) ) | 
						
							| 21 | 7 1 2 | latleeqj2 |  |-  ( ( K e. Lat /\ S e. ( Base ` K ) /\ ( ( P .\/ Q ) .\/ R ) e. ( Base ` K ) ) -> ( S .<_ ( ( P .\/ Q ) .\/ R ) <-> ( ( ( P .\/ Q ) .\/ R ) .\/ S ) = ( ( P .\/ Q ) .\/ R ) ) ) | 
						
							| 22 | 6 15 20 21 | syl3anc |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( S .<_ ( ( P .\/ Q ) .\/ R ) <-> ( ( ( P .\/ Q ) .\/ R ) .\/ S ) = ( ( P .\/ Q ) .\/ R ) ) ) | 
						
							| 23 | 18 22 | mpbid |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( ( P .\/ Q ) .\/ R ) .\/ S ) = ( ( P .\/ Q ) .\/ R ) ) | 
						
							| 24 | 17 23 | eqtr3d |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( P .\/ Q ) .\/ ( R .\/ S ) ) = ( ( P .\/ Q ) .\/ R ) ) | 
						
							| 25 |  | simp23 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> P =/= Q ) | 
						
							| 26 |  | simp32 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> -. R .<_ ( P .\/ Q ) ) | 
						
							| 27 |  | simp12 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> P e. A ) | 
						
							| 28 |  | simp13 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> Q e. A ) | 
						
							| 29 |  | eqid |  |-  ( LPlanes ` K ) = ( LPlanes ` K ) | 
						
							| 30 | 1 2 4 29 | islpln2a |  |-  ( ( K e. HL /\ ( P e. A /\ Q e. A /\ R e. A ) ) -> ( ( ( P .\/ Q ) .\/ R ) e. ( LPlanes ` K ) <-> ( P =/= Q /\ -. R .<_ ( P .\/ Q ) ) ) ) | 
						
							| 31 | 5 27 28 10 30 | syl13anc |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( ( P .\/ Q ) .\/ R ) e. ( LPlanes ` K ) <-> ( P =/= Q /\ -. R .<_ ( P .\/ Q ) ) ) ) | 
						
							| 32 | 25 26 31 | mpbir2and |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( P .\/ Q ) .\/ R ) e. ( LPlanes ` K ) ) | 
						
							| 33 | 24 32 | eqeltrd |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( P .\/ Q ) .\/ ( R .\/ S ) ) e. ( LPlanes ` K ) ) | 
						
							| 34 |  | eqid |  |-  ( LLines ` K ) = ( LLines ` K ) | 
						
							| 35 | 2 4 34 | llni2 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ P =/= Q ) -> ( P .\/ Q ) e. ( LLines ` K ) ) | 
						
							| 36 | 5 27 28 25 35 | syl31anc |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( P .\/ Q ) e. ( LLines ` K ) ) | 
						
							| 37 |  | simp31 |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> R =/= S ) | 
						
							| 38 | 2 4 34 | llni2 |  |-  ( ( ( K e. HL /\ R e. A /\ S e. A ) /\ R =/= S ) -> ( R .\/ S ) e. ( LLines ` K ) ) | 
						
							| 39 | 5 10 13 37 38 | syl31anc |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( R .\/ S ) e. ( LLines ` K ) ) | 
						
							| 40 | 2 3 4 34 29 | 2llnmj |  |-  ( ( K e. HL /\ ( P .\/ Q ) e. ( LLines ` K ) /\ ( R .\/ S ) e. ( LLines ` K ) ) -> ( ( ( P .\/ Q ) ./\ ( R .\/ S ) ) e. A <-> ( ( P .\/ Q ) .\/ ( R .\/ S ) ) e. ( LPlanes ` K ) ) ) | 
						
							| 41 | 5 36 39 40 | syl3anc |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( ( P .\/ Q ) ./\ ( R .\/ S ) ) e. A <-> ( ( P .\/ Q ) .\/ ( R .\/ S ) ) e. ( LPlanes ` K ) ) ) | 
						
							| 42 | 33 41 | mpbird |  |-  ( ( ( K e. HL /\ P e. A /\ Q e. A ) /\ ( R e. A /\ S e. A /\ P =/= Q ) /\ ( R =/= S /\ -. R .<_ ( P .\/ Q ) /\ S .<_ ( ( P .\/ Q ) .\/ R ) ) ) -> ( ( P .\/ Q ) ./\ ( R .\/ S ) ) e. A ) |