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 RLTOPSP1:68;
A4:
LSeg ((LMP D),|[0,(- 3)]|) is vertical
by A1, Th82;
A5:
|[0,(- 3)]| = |[(|[0,(- 3)]| `1),(|[0,(- 3)]| `2)]|
by EUCLID:53;
A6:
LMP D = |[((LMP D) `1),((LMP D) `2)]|
by EUCLID:53;
|[0,(- 3)]| in LSeg ((LMP D),|[0,(- 3)]|)
by RLTOPSP1:68;
then A7:
|[0,(- 3)]| `1 = (LMP D) `1
by A3, A4;
|[0,(- 3)]| `2 <= (LMP D) `2
by A1, Lm23, Th84, JORDAN21:31;
hence
p `2 <= (LMP D) `2
by A2, A5, A6, A7, JGRAPH_6:1; verum