let C be connected compact non horizontal non vertical Subset of (TOP-REAL 2); (Gauge C,1) * (Center (Gauge C,1)),1 = |[(((W-bound C) + (E-bound C)) / 2),(S-bound (L~ (Cage C,1)))]|
set G = Gauge C,1;
1 <= len (Gauge C,1)
by GOBRD11:34;
then A1:
((Gauge C,1) * (Center (Gauge C,1)),1) `1 = ((W-bound C) + (E-bound C)) / 2
by JORDAN1A:59;
Center (Gauge C,1) <= len (Gauge C,1)
by Th14;
then
((Gauge C,1) * (Center (Gauge C,1)),1) `2 = S-bound (L~ (Cage C,1))
by Th12, JORDAN1A:93;
hence
(Gauge C,1) * (Center (Gauge C,1)),1 = |[(((W-bound C) + (E-bound C)) / 2),(S-bound (L~ (Cage C,1)))]|
by A1, EUCLID:57; verum