let p be Point of (TOP-REAL 2); for D being compact with_the_max_arc Subset of (TOP-REAL 2) st |[(- 1),0 ]|,|[1,0 ]| realize-max-dist-in D & p in LSeg (LMP D),|[0 ,(- 3)]| holds
p `2 <= (LMP D) `2
let D be compact with_the_max_arc Subset of (TOP-REAL 2); ( |[(- 1),0 ]|,|[1,0 ]| realize-max-dist-in D & p in LSeg (LMP D),|[0 ,(- 3)]| implies p `2 <= (LMP D) `2 )
set x = LMP D;
assume that
A1:
|[(- 1),0 ]|,|[1,0 ]| realize-max-dist-in D
and
A2:
p in LSeg (LMP D),|[0 ,(- 3)]|
; p `2 <= (LMP D) `2
A3:
LMP D in LSeg (LMP D),|[0 ,(- 3)]|
by RLTOPSP1:69;
A4:
LSeg (LMP D),|[0 ,(- 3)]| is vertical
by A1, Th82;
A5:
|[0 ,(- 3)]| = |[(|[0 ,(- 3)]| `1 ),(|[0 ,(- 3)]| `2 )]|
by EUCLID:57;
A6:
LMP D = |[((LMP D) `1 ),((LMP D) `2 )]|
by EUCLID:57;
|[0 ,(- 3)]| in LSeg (LMP D),|[0 ,(- 3)]|
by RLTOPSP1:69;
then A7:
|[0 ,(- 3)]| `1 = (LMP D) `1
by A3, A4, SPPOL_1:def 3;
|[0 ,(- 3)]| `2 <= (LMP D) `2
by A1, Lm23, Th84, JORDAN21:44;
hence
p `2 <= (LMP D) `2
by A2, A5, A6, A7, JGRAPH_6:9; verum