let p1, p2, p3, p4 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 & LE p2,p3,P & LE p3,p4,P & ( p1 `2 >= 0 or p1 `1 >= 0 ) & ( p2 `2 >= 0 or p2 `1 >= 0 ) & ( p3 `2 >= 0 or p3 `1 >= 0 ) & ( p4 `2 > 0 or p4 `1 > 0 ) holds
ex f being Function of (TOP-REAL 2),(TOP-REAL 2) ex q1, q2, q3, q4 being Point of (TOP-REAL 2) st
( f is being_homeomorphism & ( for q being Point of (TOP-REAL 2) holds |.(f . q).| = |.q.| ) & q1 = f . p1 & q2 = f . p2 & q3 = f . p3 & q4 = f . p4 & q1 `1 < 0 & q1 `2 < 0 & q2 `1 < 0 & q2 `2 < 0 & q3 `1 < 0 & q3 `2 < 0 & q4 `1 < 0 & q4 `2 < 0 & LE q1,q2,P & LE q2,q3,P & LE q3,q4,P )
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 & LE p2,p3,P & LE p3,p4,P & ( p1 `2 >= 0 or p1 `1 >= 0 ) & ( p2 `2 >= 0 or p2 `1 >= 0 ) & ( p3 `2 >= 0 or p3 `1 >= 0 ) & ( p4 `2 > 0 or p4 `1 > 0 ) implies ex f being Function of (TOP-REAL 2),(TOP-REAL 2) ex q1, q2, q3, q4 being Point of (TOP-REAL 2) st
( f is being_homeomorphism & ( for q being Point of (TOP-REAL 2) holds |.(f . q).| = |.q.| ) & q1 = f . p1 & q2 = f . p2 & q3 = f . p3 & q4 = f . p4 & q1 `1 < 0 & q1 `2 < 0 & q2 `1 < 0 & q2 `2 < 0 & q3 `1 < 0 & q3 `2 < 0 & q4 `1 < 0 & q4 `2 < 0 & LE q1,q2,P & LE q2,q3,P & LE q3,q4,P ) )
assume that
A1:
P = { p where p is Point of (TOP-REAL 2) : |.p.| = 1 }
and
A2:
( LE p1,p2,P & LE p2,p3,P & LE p3,p4,P & ( p1 `2 >= 0 or p1 `1 >= 0 ) & ( p2 `2 >= 0 or p2 `1 >= 0 ) & ( p3 `2 >= 0 or p3 `1 >= 0 ) & ( p4 `2 > 0 or p4 `1 > 0 ) )
; ex f being Function of (TOP-REAL 2),(TOP-REAL 2) ex q1, q2, q3, q4 being Point of (TOP-REAL 2) st
( f is being_homeomorphism & ( for q being Point of (TOP-REAL 2) holds |.(f . q).| = |.q.| ) & q1 = f . p1 & q2 = f . p2 & q3 = f . p3 & q4 = f . p4 & q1 `1 < 0 & q1 `2 < 0 & q2 `1 < 0 & q2 `2 < 0 & q3 `1 < 0 & q3 `2 < 0 & q4 `1 < 0 & q4 `2 < 0 & LE q1,q2,P & LE q2,q3,P & LE q3,q4,P )
consider f being Function of (TOP-REAL 2),(TOP-REAL 2), q1, q2, q3, q4 being Point of (TOP-REAL 2) such that
A3:
f is being_homeomorphism
and
A4:
for q being Point of (TOP-REAL 2) holds |.(f . q).| = |.q.|
and
A5:
( q1 = f . p1 & q2 = f . p2 )
and
A6:
( q3 = f . p3 & q4 = f . p4 )
and
A7:
( q1 `2 >= 0 & q2 `2 >= 0 & q3 `2 >= 0 & q4 `2 > 0 & LE q1,q2,P & LE q2,q3,P & LE q3,q4,P )
by A1, A2, Th62;
consider f2 being Function of (TOP-REAL 2),(TOP-REAL 2), q1b, q2b, q3b, q4b being Point of (TOP-REAL 2) such that
A8:
f2 is being_homeomorphism
and
A9:
for q being Point of (TOP-REAL 2) holds |.(f2 . q).| = |.q.|
and
A10:
( q1b = f2 . q1 & q2b = f2 . q2 )
and
A11:
( q3b = f2 . q3 & q4b = f2 . q4 )
and
A12:
( q1b `1 < 0 & q1b `2 < 0 & q2b `1 < 0 & q2b `2 < 0 & q3b `1 < 0 & q3b `2 < 0 & q4b `1 < 0 & q4b `2 < 0 & LE q1b,q2b,P & LE q2b,q3b,P & LE q3b,q4b,P )
by A1, A7, Th61;
reconsider f3 = f2 * f as Function of (TOP-REAL 2),(TOP-REAL 2) ;
A13:
f3 is being_homeomorphism
by A3, A8, TOPS_2:57;
A14:
dom f = the carrier of (TOP-REAL 2)
by FUNCT_2:def 1;
then A15:
( f3 . p3 = q3b & f3 . p4 = q4b )
by A6, A11, FUNCT_1:13;
A16:
for q being Point of (TOP-REAL 2) holds |.(f3 . q).| = |.q.|
( f3 . p1 = q1b & f3 . p2 = q2b )
by A5, A10, A14, FUNCT_1:13;
hence
ex f being Function of (TOP-REAL 2),(TOP-REAL 2) ex q1, q2, q3, q4 being Point of (TOP-REAL 2) st
( f is being_homeomorphism & ( for q being Point of (TOP-REAL 2) holds |.(f . q).| = |.q.| ) & q1 = f . p1 & q2 = f . p2 & q3 = f . p3 & q4 = f . p4 & q1 `1 < 0 & q1 `2 < 0 & q2 `1 < 0 & q2 `2 < 0 & q3 `1 < 0 & q3 `2 < 0 & q4 `1 < 0 & q4 `2 < 0 & LE q1,q2,P & LE q2,q3,P & LE q3,q4,P )
by A12, A13, A16, A15; verum