| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lplni2.l |  |-  .<_ = ( le ` K ) | 
						
							| 2 |  | lplni2.j |  |-  .\/ = ( join ` K ) | 
						
							| 3 |  | lplni2.a |  |-  A = ( Atoms ` K ) | 
						
							| 4 |  | lplni2.p |  |-  P = ( LPlanes ` K ) | 
						
							| 5 |  | simp2 |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> ( Q e. A /\ R e. A /\ S e. A ) ) | 
						
							| 6 |  | simp3l |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> Q =/= R ) | 
						
							| 7 |  | simp3r |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> -. S .<_ ( Q .\/ R ) ) | 
						
							| 8 |  | eqidd |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ R ) .\/ S ) ) | 
						
							| 9 |  | neeq1 |  |-  ( q = Q -> ( q =/= r <-> Q =/= r ) ) | 
						
							| 10 |  | oveq1 |  |-  ( q = Q -> ( q .\/ r ) = ( Q .\/ r ) ) | 
						
							| 11 | 10 | breq2d |  |-  ( q = Q -> ( s .<_ ( q .\/ r ) <-> s .<_ ( Q .\/ r ) ) ) | 
						
							| 12 | 11 | notbid |  |-  ( q = Q -> ( -. s .<_ ( q .\/ r ) <-> -. s .<_ ( Q .\/ r ) ) ) | 
						
							| 13 | 10 | oveq1d |  |-  ( q = Q -> ( ( q .\/ r ) .\/ s ) = ( ( Q .\/ r ) .\/ s ) ) | 
						
							| 14 | 13 | eqeq2d |  |-  ( q = Q -> ( ( ( Q .\/ R ) .\/ S ) = ( ( q .\/ r ) .\/ s ) <-> ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ r ) .\/ s ) ) ) | 
						
							| 15 | 9 12 14 | 3anbi123d |  |-  ( q = Q -> ( ( q =/= r /\ -. s .<_ ( q .\/ r ) /\ ( ( Q .\/ R ) .\/ S ) = ( ( q .\/ r ) .\/ s ) ) <-> ( Q =/= r /\ -. s .<_ ( Q .\/ r ) /\ ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ r ) .\/ s ) ) ) ) | 
						
							| 16 |  | neeq2 |  |-  ( r = R -> ( Q =/= r <-> Q =/= R ) ) | 
						
							| 17 |  | oveq2 |  |-  ( r = R -> ( Q .\/ r ) = ( Q .\/ R ) ) | 
						
							| 18 | 17 | breq2d |  |-  ( r = R -> ( s .<_ ( Q .\/ r ) <-> s .<_ ( Q .\/ R ) ) ) | 
						
							| 19 | 18 | notbid |  |-  ( r = R -> ( -. s .<_ ( Q .\/ r ) <-> -. s .<_ ( Q .\/ R ) ) ) | 
						
							| 20 | 17 | oveq1d |  |-  ( r = R -> ( ( Q .\/ r ) .\/ s ) = ( ( Q .\/ R ) .\/ s ) ) | 
						
							| 21 | 20 | eqeq2d |  |-  ( r = R -> ( ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ r ) .\/ s ) <-> ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ R ) .\/ s ) ) ) | 
						
							| 22 | 16 19 21 | 3anbi123d |  |-  ( r = R -> ( ( Q =/= r /\ -. s .<_ ( Q .\/ r ) /\ ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ r ) .\/ s ) ) <-> ( Q =/= R /\ -. s .<_ ( Q .\/ R ) /\ ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ R ) .\/ s ) ) ) ) | 
						
							| 23 |  | breq1 |  |-  ( s = S -> ( s .<_ ( Q .\/ R ) <-> S .<_ ( Q .\/ R ) ) ) | 
						
							| 24 | 23 | notbid |  |-  ( s = S -> ( -. s .<_ ( Q .\/ R ) <-> -. S .<_ ( Q .\/ R ) ) ) | 
						
							| 25 |  | oveq2 |  |-  ( s = S -> ( ( Q .\/ R ) .\/ s ) = ( ( Q .\/ R ) .\/ S ) ) | 
						
							| 26 | 25 | eqeq2d |  |-  ( s = S -> ( ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ R ) .\/ s ) <-> ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ R ) .\/ S ) ) ) | 
						
							| 27 | 24 26 | 3anbi23d |  |-  ( s = S -> ( ( Q =/= R /\ -. s .<_ ( Q .\/ R ) /\ ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ R ) .\/ s ) ) <-> ( Q =/= R /\ -. S .<_ ( Q .\/ R ) /\ ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ R ) .\/ S ) ) ) ) | 
						
							| 28 | 15 22 27 | rspc3ev |  |-  ( ( ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) /\ ( ( Q .\/ R ) .\/ S ) = ( ( Q .\/ R ) .\/ S ) ) ) -> E. q e. A E. r e. A E. s e. A ( q =/= r /\ -. s .<_ ( q .\/ r ) /\ ( ( Q .\/ R ) .\/ S ) = ( ( q .\/ r ) .\/ s ) ) ) | 
						
							| 29 | 5 6 7 8 28 | syl13anc |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> E. q e. A E. r e. A E. s e. A ( q =/= r /\ -. s .<_ ( q .\/ r ) /\ ( ( Q .\/ R ) .\/ S ) = ( ( q .\/ r ) .\/ s ) ) ) | 
						
							| 30 |  | simp1 |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> K e. HL ) | 
						
							| 31 |  | hllat |  |-  ( K e. HL -> K e. Lat ) | 
						
							| 32 | 31 | 3ad2ant1 |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> K e. Lat ) | 
						
							| 33 |  | simp21 |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> Q e. A ) | 
						
							| 34 |  | simp22 |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> R e. A ) | 
						
							| 35 |  | eqid |  |-  ( Base ` K ) = ( Base ` K ) | 
						
							| 36 | 35 2 3 | hlatjcl |  |-  ( ( K e. HL /\ Q e. A /\ R e. A ) -> ( Q .\/ R ) e. ( Base ` K ) ) | 
						
							| 37 | 30 33 34 36 | syl3anc |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> ( Q .\/ R ) e. ( Base ` K ) ) | 
						
							| 38 |  | simp23 |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> S e. A ) | 
						
							| 39 | 35 3 | atbase |  |-  ( S e. A -> S e. ( Base ` K ) ) | 
						
							| 40 | 38 39 | syl |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> S e. ( Base ` K ) ) | 
						
							| 41 | 35 2 | latjcl |  |-  ( ( K e. Lat /\ ( Q .\/ R ) e. ( Base ` K ) /\ S e. ( Base ` K ) ) -> ( ( Q .\/ R ) .\/ S ) e. ( Base ` K ) ) | 
						
							| 42 | 32 37 40 41 | syl3anc |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> ( ( Q .\/ R ) .\/ S ) e. ( Base ` K ) ) | 
						
							| 43 | 35 1 2 3 4 | islpln5 |  |-  ( ( K e. HL /\ ( ( Q .\/ R ) .\/ S ) e. ( Base ` K ) ) -> ( ( ( Q .\/ R ) .\/ S ) e. P <-> E. q e. A E. r e. A E. s e. A ( q =/= r /\ -. s .<_ ( q .\/ r ) /\ ( ( Q .\/ R ) .\/ S ) = ( ( q .\/ r ) .\/ s ) ) ) ) | 
						
							| 44 | 30 42 43 | syl2anc |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> ( ( ( Q .\/ R ) .\/ S ) e. P <-> E. q e. A E. r e. A E. s e. A ( q =/= r /\ -. s .<_ ( q .\/ r ) /\ ( ( Q .\/ R ) .\/ S ) = ( ( q .\/ r ) .\/ s ) ) ) ) | 
						
							| 45 | 29 44 | mpbird |  |-  ( ( K e. HL /\ ( Q e. A /\ R e. A /\ S e. A ) /\ ( Q =/= R /\ -. S .<_ ( Q .\/ R ) ) ) -> ( ( Q .\/ R ) .\/ S ) e. P ) |