let p1, p2 be Point of (TOP-REAL 2); for P being non empty compact Subset of (TOP-REAL 2) st P = { p where p is Point of (TOP-REAL 2) : |.p.| = 1 } & LE p1,p2,P & p1 <> p2 & p1 `1 < 0 & p1 `2 < 0 & p2 `2 < 0 holds
( p1 `1 > p2 `1 & p1 `2 < p2 `2 )
let P be non empty compact Subset of (TOP-REAL 2); ( P = { p where p is Point of (TOP-REAL 2) : |.p.| = 1 } & LE p1,p2,P & p1 <> p2 & p1 `1 < 0 & p1 `2 < 0 & p2 `2 < 0 implies ( p1 `1 > p2 `1 & p1 `2 < p2 `2 ) )
assume that
A1:
P = { p where p is Point of (TOP-REAL 2) : |.p.| = 1 }
and
A2:
LE p1,p2,P
and
A3:
p1 <> p2
and
A4:
p1 `1 < 0
and
A5:
p1 `2 < 0
and
A6:
p2 `2 < 0
; ( p1 `1 > p2 `1 & p1 `2 < p2 `2 )
consider f being Function of I[01],((TOP-REAL 2) | (Lower_Arc P)) such that
A7:
f is being_homeomorphism
and
A8:
for q1, q2 being Point of (TOP-REAL 2)
for r1, r2 being Real st f . r1 = q1 & f . r2 = q2 & r1 in [.0,1.] & r2 in [.0,1.] holds
( r1 < r2 iff q1 `1 > q2 `1 )
and
A9:
( f . 0 = E-max P & f . 1 = W-min P )
by A1, Th42;
A10: rng f =
[#] ((TOP-REAL 2) | (Lower_Arc P))
by A7, TOPS_2:def 5
.=
Lower_Arc P
by PRE_TOPC:def 5
;
A11:
Upper_Arc P = { p where p is Point of (TOP-REAL 2) : ( p in P & p `2 >= 0 ) }
by A1, Th34;
then A13:
LE p1,p2, Lower_Arc P, E-max P, W-min P
by A2;
p2 in Lower_Arc P
by A2, A12;
then consider x2 being object such that
A14:
x2 in dom f
and
A15:
p2 = f . x2
by A10, FUNCT_1:def 3;
A16: dom f =
[#] I[01]
by A7, TOPS_2:def 5
.=
[.0,1.]
by BORSUK_1:40
;
reconsider r22 = x2 as Real by A14;
A17:
( 0 <= r22 & r22 <= 1 )
by A14, A16, XXREAL_1:1;
p1 in Lower_Arc P
by A2, A12;
then consider x1 being object such that
A18:
x1 in dom f
and
A19:
p1 = f . x1
by A10, FUNCT_1:def 3;
reconsider r11 = x1 as Real by A18;
r11 <= 1
by A18, A16, XXREAL_1:1;
then A20:
r11 <= r22
by A13, A7, A9, A19, A15, A17, JORDAN5C:def 3;
A21:
P is being_simple_closed_curve
by A1, JGRAPH_3:26;
then
p1 in P
by A2, JORDAN7:5;
then
ex p3 being Point of (TOP-REAL 2) st
( p3 = p1 & |.p3.| = 1 )
by A1;
then
1 ^2 = ((p1 `1) ^2) + ((p1 `2) ^2)
by JGRAPH_3:1;
then
(1 ^2) - ((p1 `1) ^2) = (- (p1 `2)) ^2
;
then
- (p1 `2) = sqrt ((1 ^2) - ((- (p1 `1)) ^2))
by A5, SQUARE_1:22;
then A22:
p1 `2 = - (sqrt ((1 ^2) - ((- (p1 `1)) ^2)))
;
p2 in P
by A2, A21, JORDAN7:5;
then
ex p4 being Point of (TOP-REAL 2) st
( p4 = p2 & |.p4.| = 1 )
by A1;
then A23:
1 ^2 = ((p2 `1) ^2) + ((p2 `2) ^2)
by JGRAPH_3:1;
then
(1 ^2) - ((p2 `1) ^2) = (- (p2 `2)) ^2
;
then
- (p2 `2) = sqrt ((1 ^2) - ((- (p2 `1)) ^2))
by A6, SQUARE_1:22;
then A24:
p2 `2 = - (sqrt ((1 ^2) - ((- (p2 `1)) ^2)))
;
A25:
( r11 < r22 iff p1 `1 > p2 `1 )
by A8, A18, A19, A14, A15, A16;
then
- (p1 `1) < - (p2 `1)
by A3, A19, A15, A20, XREAL_1:24, XXREAL_0:1;
then
(- (p1 `1)) ^2 < (- (p2 `1)) ^2
by A4, SQUARE_1:16;
then
(1 ^2) - ((- (p1 `1)) ^2) > (1 ^2) - ((- (p2 `1)) ^2)
by XREAL_1:15;
then
sqrt ((1 ^2) - ((- (p1 `1)) ^2)) > sqrt ((1 ^2) - ((- (p2 `1)) ^2))
by A23, SQUARE_1:27, XREAL_1:63;
hence
( p1 `1 > p2 `1 & p1 `2 < p2 `2 )
by A19, A15, A25, A20, A22, A24, XREAL_1:24, XXREAL_0:1; verum