let P be non empty compact Subset of (TOP-REAL 2); for q1, q2 being Point of (TOP-REAL 2) st P is being_simple_closed_curve & LE q1,q2,P & q1 <> q2 & q1 <> W-min P holds
(Segment (q2,(W-min P),P)) /\ (Segment ((W-min P),q1,P)) = {(W-min P)}
let q1, q2 be Point of (TOP-REAL 2); ( P is being_simple_closed_curve & LE q1,q2,P & q1 <> q2 & q1 <> W-min P implies (Segment (q2,(W-min P),P)) /\ (Segment ((W-min P),q1,P)) = {(W-min P)} )
assume that
A1:
P is being_simple_closed_curve
and
A2:
LE q1,q2,P
and
A3:
q1 <> q2
and
A4:
q1 <> W-min P
; (Segment (q2,(W-min P),P)) /\ (Segment ((W-min P),q1,P)) = {(W-min P)}
thus
(Segment (q2,(W-min P),P)) /\ (Segment ((W-min P),q1,P)) c= {(W-min P)}
XBOOLE_0:def 10 {(W-min P)} c= (Segment (q2,(W-min P),P)) /\ (Segment ((W-min P),q1,P))proof
let x be
object ;
TARSKI:def 3 ( not x in (Segment (q2,(W-min P),P)) /\ (Segment ((W-min P),q1,P)) or x in {(W-min P)} )
assume A5:
x in (Segment (q2,(W-min P),P)) /\ (Segment ((W-min P),q1,P))
;
x in {(W-min P)}
then
x in Segment (
q2,
(W-min P),
P)
by XBOOLE_0:def 4;
then
x in { p1 where p1 is Point of (TOP-REAL 2) : ( LE q2,p1,P or ( q2 in P & p1 = W-min P ) ) }
by Def1;
then consider p1 being
Point of
(TOP-REAL 2) such that A6:
p1 = x
and A7:
(
LE q2,
p1,
P or (
q2 in P &
p1 = W-min P ) )
;
A8:
x in Segment (
(W-min P),
q1,
P)
by A5, XBOOLE_0:def 4;
now ( ( LE q2,p1,P & contradiction ) or ( q2 in P & p1 = W-min P & x = W-min P ) )per cases
( LE q2,p1,P or ( q2 in P & p1 = W-min P ) )
by A7;
case A9:
LE q2,
p1,
P
;
contradiction
x in { p where p is Point of (TOP-REAL 2) : ( LE W-min P,p,P & LE p,q1,P ) }
by A4, A8, Def1;
then
ex
p2 being
Point of
(TOP-REAL 2) st
(
p2 = x &
LE W-min P,
p2,
P &
LE p2,
q1,
P )
;
then
LE q2,
q1,
P
by A1, A6, A9, JORDAN6:58;
hence
contradiction
by A1, A2, A3, JORDAN6:57;
verum end; end; end;
hence
x in {(W-min P)}
by TARSKI:def 1;
verum
end;
let x be object ; TARSKI:def 3 ( not x in {(W-min P)} or x in (Segment (q2,(W-min P),P)) /\ (Segment ((W-min P),q1,P)) )
assume
x in {(W-min P)}
; x in (Segment (q2,(W-min P),P)) /\ (Segment ((W-min P),q1,P))
then A10:
x = W-min P
by TARSKI:def 1;
q2 in P
by A1, A2, Th5;
then
x in { p1 where p1 is Point of (TOP-REAL 2) : ( LE q2,p1,P or ( q2 in P & p1 = W-min P ) ) }
by A10;
then A11:
x in Segment (q2,(W-min P),P)
by Def1;
q1 in P
by A1, A2, Th5;
then
LE W-min P,q1,P
by A1, Th3;
then
x in Segment ((W-min P),q1,P)
by A1, A10, Th6;
hence
x in (Segment (q2,(W-min P),P)) /\ (Segment ((W-min P),q1,P))
by A11, XBOOLE_0:def 4; verum