let P be Subset of (TOP-REAL 2); :: thesis: for q being Point of (TOP-REAL 2) st P is being_simple_closed_curve & q in P holds
LE q,q,P
let q be Point of (TOP-REAL 2); :: thesis: ( P is being_simple_closed_curve & q in P implies LE q,q,P )
assume A1:
( P is being_simple_closed_curve & q in P )
; :: thesis: LE q,q,P
then A2:
( Lower_Arc P is_an_arc_of E-max P, W-min P & (Upper_Arc P) /\ (Lower_Arc P) = {(W-min P),(E-max P)} & (Upper_Arc P) \/ (Lower_Arc P) = P & (First_Point (Upper_Arc P),(W-min P),(E-max P),(Vertical_Line (((W-bound P) + (E-bound P)) / 2))) `2 > (Last_Point (Lower_Arc P),(E-max P),(W-min P),(Vertical_Line (((W-bound P) + (E-bound P)) / 2))) `2 )
by Def9;
A3:
Upper_Arc P is_an_arc_of W-min P, E-max P
by A1, Th65;
now per cases
( q in Upper_Arc P or ( q in Lower_Arc P & not q in Upper_Arc P ) )
by A1, A2, XBOOLE_0:def 3;
case A5:
(
q in Lower_Arc P & not
q in Upper_Arc P )
;
:: thesis: LE q,q,Pthen A6:
LE q,
q,
Lower_Arc P,
E-max P,
W-min P
by JORDAN5C:9;
q <> W-min P
by A3, A5, TOPREAL1:4;
hence
LE q,
q,
P
by A5, A6, Def10;
:: thesis: verum end; end; end;
hence
LE q,q,P
; :: thesis: verum