let m be Nat; for r being non negative Real
for f being continuous Function of (Tcircle ((0. (TOP-REAL (m + 1))),r)),(TOP-REAL m) holds f (-) is continuous Function of (Tcircle ((0. (TOP-REAL (m + 1))),r)),(TOP-REAL m)
let r be non negative Real; for f being continuous Function of (Tcircle ((0. (TOP-REAL (m + 1))),r)),(TOP-REAL m) holds f (-) is continuous Function of (Tcircle ((0. (TOP-REAL (m + 1))),r)),(TOP-REAL m)
set T = Tcircle ((0. (TOP-REAL (m + 1))),r);
let f be continuous Function of (Tcircle ((0. (TOP-REAL (m + 1))),r)),(TOP-REAL m); f (-) is continuous Function of (Tcircle ((0. (TOP-REAL (m + 1))),r)),(TOP-REAL m)
reconsider g = f (-) as Function of (Tcircle ((0. (TOP-REAL (m + 1))),r)),(TOP-REAL m) by Th61;
for p being Point of (Tcircle ((0. (TOP-REAL (m + 1))),r))
for r being positive Real ex W being open Subset of (Tcircle ((0. (TOP-REAL (m + 1))),r)) st
( p in W & g .: W c= Ball ((g . p),r) )
proof
let p be
Point of
(Tcircle ((0. (TOP-REAL (m + 1))),r));
for r being positive Real ex W being open Subset of (Tcircle ((0. (TOP-REAL (m + 1))),r)) st
( p in W & g .: W c= Ball ((g . p),r) )let r be
positive Real;
ex W being open Subset of (Tcircle ((0. (TOP-REAL (m + 1))),r)) st
( p in W & g .: W c= Ball ((g . p),r) )
reconsider q =
- p as
Point of
(Tcircle ((0. (TOP-REAL (m + 1))),r)) by Th60;
consider W being
open Subset of
(Tcircle ((0. (TOP-REAL (m + 1))),r)) such that A1:
q in W
and A2:
f .: W c= Ball (
(f . q),
r)
by TOPS_4:18;
reconsider W1 =
(-) W as
open Subset of
(Tcircle ((0. (TOP-REAL (m + 1))),r)) ;
take
W1
;
( p in W1 & g .: W1 c= Ball ((g . p),r) )
- q in W1
by A1, Def3;
hence
p in W1
;
g .: W1 c= Ball ((g . p),r)
let y be
Element of
(TOP-REAL m);
LATTICE7:def 1 ( not y in g .: W1 or y in Ball ((g . p),r) )
assume
y in g .: W1
;
y in Ball ((g . p),r)
then consider x being
Element of
(Tcircle ((0. (TOP-REAL (m + 1))),r)) such that A3:
x in W1
and A4:
g . x = y
by FUNCT_2:65;
dom g = the
carrier of
(Tcircle ((0. (TOP-REAL (m + 1))),r))
by FUNCT_2:def 1;
then A5:
(
g . x = f . (- x) &
g . p = f . (- p) )
by VALUED_2:def 34;
- x in (-) W1
by A3, Def3;
then
f . (- x) in f .: W
by FUNCT_2:35;
hence
y in Ball (
(g . p),
r)
by A2, A4, A5;
verum
end;
hence
f (-) is continuous Function of (Tcircle ((0. (TOP-REAL (m + 1))),r)),(TOP-REAL m)
by TOPS_4:18; verum