let P be non empty compact Subset of (TOP-REAL 2); :: thesis: for q1, q2 being Point of (TOP-REAL 2) st P is being_simple_closed_curve & LE q1,q2,P holds
( q1 in Segment q1,q2,P & q2 in Segment q1,q2,P )
let q1, q2 be Point of (TOP-REAL 2); :: thesis: ( P is being_simple_closed_curve & LE q1,q2,P implies ( q1 in Segment q1,q2,P & q2 in Segment q1,q2,P ) )
assume A1:
( P is being_simple_closed_curve & LE q1,q2,P )
; :: thesis: ( q1 in Segment q1,q2,P & q2 in Segment q1,q2,P )
hereby :: thesis: q2 in Segment q1,q2,P
per cases
( q2 <> W-min P or q2 = W-min P )
;
suppose A2:
q2 <> W-min P
;
:: thesis: q1 in Segment q1,q2,P
q1 in P
by A1, Th5;
then
LE q1,
q1,
P
by A1, JORDAN6:71;
then
q1 in { p where p is Point of (TOP-REAL 2) : ( LE q1,p,P & LE p,q2,P ) }
by A1;
hence
q1 in Segment q1,
q2,
P
by A2, Def1;
:: thesis: verum end; end;
end;
per cases
( q2 <> W-min P or q2 = W-min P )
;
suppose A4:
q2 <> W-min P
;
:: thesis: q2 in Segment q1,q2,P
q2 in P
by A1, Th5;
then
LE q2,
q2,
P
by A1, JORDAN6:71;
then
q2 in { p where p is Point of (TOP-REAL 2) : ( LE q1,p,P & LE p,q2,P ) }
by A1;
hence
q2 in Segment q1,
q2,
P
by A4, Def1;
:: thesis: verum end; end;