reconsider D = NonZero (TOP-REAL 2) as non empty Subset of (TOP-REAL 2) by JGRAPH_2:19;
let cn be Real; ( - 1 < cn & cn < 1 implies ex h being Function of (TOP-REAL 2),(TOP-REAL 2) st
( h = cn -FanMorphN & h is continuous ) )
assume that
A1:
- 1 < cn
and
A2:
cn < 1
; ex h being Function of (TOP-REAL 2),(TOP-REAL 2) st
( h = cn -FanMorphN & h is continuous )
reconsider f = cn -FanMorphN as Function of (TOP-REAL 2),(TOP-REAL 2) ;
A3:
f . (0. (TOP-REAL 2)) = 0. (TOP-REAL 2)
by Th56, JGRAPH_2:11;
A4:
for p being Point of ((TOP-REAL 2) | D) holds f . p <> f . (0. (TOP-REAL 2))
A15:
for V being Subset of (TOP-REAL 2) st f . (0. (TOP-REAL 2)) in V & V is open holds
ex W being Subset of (TOP-REAL 2) st
( 0. (TOP-REAL 2) in W & W is open & f .: W c= V )
proof
reconsider u0 =
0. (TOP-REAL 2) as
Point of
(Euclid 2) by EUCLID:71;
let V be
Subset of
(TOP-REAL 2);
( f . (0. (TOP-REAL 2)) in V & V is open implies ex W being Subset of (TOP-REAL 2) st
( 0. (TOP-REAL 2) in W & W is open & f .: W c= V ) )
reconsider VV =
V as
Subset of
(TopSpaceMetr (Euclid 2)) by Lm11;
assume that A16:
f . (0. (TOP-REAL 2)) in V
and A17:
V is
open
;
ex W being Subset of (TOP-REAL 2) st
( 0. (TOP-REAL 2) in W & W is open & f .: W c= V )
VV is
open
by A17, Lm11, PRE_TOPC:60;
then consider r being
real number such that A18:
r > 0
and A19:
Ball u0,
r c= V
by A3, A16, TOPMETR:22;
reconsider r =
r as
Real by XREAL_0:def 1;
TopStruct(# the
carrier of
(TOP-REAL 2),the
topology of
(TOP-REAL 2) #)
= TopSpaceMetr (Euclid 2)
by EUCLID:def 8;
then reconsider W1 =
Ball u0,
r as
Subset of
(TOP-REAL 2) ;
A20:
W1 is
open
by GOBOARD6:6;
A21:
f .: W1 c= W1
proof
let z be
set ;
TARSKI:def 3 ( not z in f .: W1 or z in W1 )
assume
z in f .: W1
;
z in W1
then consider y being
set such that A22:
y in dom f
and A23:
y in W1
and A24:
z = f . y
by FUNCT_1:def 12;
z in rng f
by A22, A24, FUNCT_1:def 5;
then reconsider qz =
z as
Point of
(TOP-REAL 2) ;
reconsider q =
y as
Point of
(TOP-REAL 2) by A22;
reconsider qy =
q as
Point of
(Euclid 2) by EUCLID:71;
reconsider pz =
qz as
Point of
(Euclid 2) by EUCLID:71;
dist u0,
qy < r
by A23, METRIC_1:12;
then A25:
|.((0. (TOP-REAL 2)) - q).| < r
by JGRAPH_1:45;
now per cases
( q `2 <= 0 or ( q <> 0. (TOP-REAL 2) & (q `1 ) / |.q.| >= cn & q `2 >= 0 ) or ( q <> 0. (TOP-REAL 2) & (q `1 ) / |.q.| < cn & q `2 >= 0 ) )
by JGRAPH_2:11;
case A26:
(
q <> 0. (TOP-REAL 2) &
(q `1 ) / |.q.| >= cn &
q `2 >= 0 )
;
z in W1then A27:
((q `1 ) / |.q.|) - cn >= 0
by XREAL_1:50;
0 <= (q `2 ) ^2
by XREAL_1:65;
then
(
|.q.| ^2 = ((q `1 ) ^2 ) + ((q `2 ) ^2 ) &
0 + ((q `1 ) ^2 ) <= ((q `1 ) ^2 ) + ((q `2 ) ^2 ) )
by JGRAPH_3:10, XREAL_1:9;
then A28:
((q `1 ) ^2 ) / (|.q.| ^2 ) <= (|.q.| ^2 ) / (|.q.| ^2 )
by XREAL_1:74;
A29:
1
- cn > 0
by A2, XREAL_1:151;
|.q.| <> 0
by A26, TOPRNS_1:25;
then
|.q.| ^2 > 0
by SQUARE_1:74;
then
((q `1 ) ^2 ) / (|.q.| ^2 ) <= 1
by A28, XCMPLX_1:60;
then
((q `1 ) / |.q.|) ^2 <= 1
by XCMPLX_1:77;
then
1
>= (q `1 ) / |.q.|
by SQUARE_1:121;
then
1
- cn >= ((q `1 ) / |.q.|) - cn
by XREAL_1:11;
then
- (1 - cn) <= - (((q `1 ) / |.q.|) - cn)
by XREAL_1:26;
then
(- (1 - cn)) / (1 - cn) <= (- (((q `1 ) / |.q.|) - cn)) / (1 - cn)
by A29, XREAL_1:74;
then
- 1
<= (- (((q `1 ) / |.q.|) - cn)) / (1 - cn)
by A29, XCMPLX_1:198;
then
((- (((q `1 ) / |.q.|) - cn)) / (1 - cn)) ^2 <= 1
^2
by A29, A27, SQUARE_1:119;
then
1
- (((- (((q `1 ) / |.q.|) - cn)) / (1 - cn)) ^2 ) >= 0
by XREAL_1:50;
then A30:
1
- ((- ((((q `1 ) / |.q.|) - cn) / (1 - cn))) ^2 ) >= 0
by XCMPLX_1:188;
A31:
(cn -FanMorphN ) . q = |[(|.q.| * ((((q `1 ) / |.q.|) - cn) / (1 - cn))),(|.q.| * (sqrt (1 - (((((q `1 ) / |.q.|) - cn) / (1 - cn)) ^2 ))))]|
by A1, A2, A26, Th58;
then A32:
qz `1 = |.q.| * ((((q `1 ) / |.q.|) - cn) / (1 - cn))
by A24, EUCLID:56;
qz `2 = |.q.| * (sqrt (1 - (((((q `1 ) / |.q.|) - cn) / (1 - cn)) ^2 )))
by A24, A31, EUCLID:56;
then A33:
(qz `2 ) ^2 =
(|.q.| ^2 ) * ((sqrt (1 - (((((q `1 ) / |.q.|) - cn) / (1 - cn)) ^2 ))) ^2 )
.=
(|.q.| ^2 ) * (1 - (((((q `1 ) / |.q.|) - cn) / (1 - cn)) ^2 ))
by A30, SQUARE_1:def 4
;
|.qz.| ^2 =
((qz `1 ) ^2 ) + ((qz `2 ) ^2 )
by JGRAPH_3:10
.=
|.q.| ^2
by A32, A33
;
then
sqrt (|.qz.| ^2 ) = |.q.|
by SQUARE_1:89;
then A34:
|.qz.| = |.q.|
by SQUARE_1:89;
|.(- q).| < r
by A25, EUCLID:31;
then
|.q.| < r
by TOPRNS_1:27;
then
|.(- qz).| < r
by A34, TOPRNS_1:27;
then
|.((0. (TOP-REAL 2)) - qz).| < r
by EUCLID:31;
then
dist u0,
pz < r
by JGRAPH_1:45;
hence
z in W1
by METRIC_1:12;
verum end; case A35:
(
q <> 0. (TOP-REAL 2) &
(q `1 ) / |.q.| < cn &
q `2 >= 0 )
;
z in W1
0 <= (q `2 ) ^2
by XREAL_1:65;
then
(
|.q.| ^2 = ((q `1 ) ^2 ) + ((q `2 ) ^2 ) &
0 + ((q `1 ) ^2 ) <= ((q `1 ) ^2 ) + ((q `2 ) ^2 ) )
by JGRAPH_3:10, XREAL_1:9;
then A36:
((q `1 ) ^2 ) / (|.q.| ^2 ) <= (|.q.| ^2 ) / (|.q.| ^2 )
by XREAL_1:74;
A37:
1
+ cn > 0
by A1, XREAL_1:150;
|.q.| <> 0
by A35, TOPRNS_1:25;
then
|.q.| ^2 > 0
by SQUARE_1:74;
then
((q `1 ) ^2 ) / (|.q.| ^2 ) <= 1
by A36, XCMPLX_1:60;
then
((q `1 ) / |.q.|) ^2 <= 1
by XCMPLX_1:77;
then
- 1
<= (q `1 ) / |.q.|
by SQUARE_1:121;
then
- (- 1) >= - ((q `1 ) / |.q.|)
by XREAL_1:26;
then
1
+ cn >= (- ((q `1 ) / |.q.|)) + cn
by XREAL_1:9;
then A38:
(- (((q `1 ) / |.q.|) - cn)) / (1 + cn) <= 1
by A37, XREAL_1:187;
cn - ((q `1 ) / |.q.|) >= 0
by A35, XREAL_1:50;
then
- 1
<= (- (((q `1 ) / |.q.|) - cn)) / (1 + cn)
by A37;
then
((- (((q `1 ) / |.q.|) - cn)) / (1 + cn)) ^2 <= 1
^2
by A38, SQUARE_1:119;
then
1
- (((- (((q `1 ) / |.q.|) - cn)) / (1 + cn)) ^2 ) >= 0
by XREAL_1:50;
then A39:
1
- ((- ((((q `1 ) / |.q.|) - cn) / (1 + cn))) ^2 ) >= 0
by XCMPLX_1:188;
A40:
(cn -FanMorphN ) . q = |[(|.q.| * ((((q `1 ) / |.q.|) - cn) / (1 + cn))),(|.q.| * (sqrt (1 - (((((q `1 ) / |.q.|) - cn) / (1 + cn)) ^2 ))))]|
by A1, A2, A35, Th58;
then A41:
qz `1 = |.q.| * ((((q `1 ) / |.q.|) - cn) / (1 + cn))
by A24, EUCLID:56;
qz `2 = |.q.| * (sqrt (1 - (((((q `1 ) / |.q.|) - cn) / (1 + cn)) ^2 )))
by A24, A40, EUCLID:56;
then A42:
(qz `2 ) ^2 =
(|.q.| ^2 ) * ((sqrt (1 - (((((q `1 ) / |.q.|) - cn) / (1 + cn)) ^2 ))) ^2 )
.=
(|.q.| ^2 ) * (1 - (((((q `1 ) / |.q.|) - cn) / (1 + cn)) ^2 ))
by A39, SQUARE_1:def 4
;
|.qz.| ^2 =
((qz `1 ) ^2 ) + ((qz `2 ) ^2 )
by JGRAPH_3:10
.=
|.q.| ^2
by A41, A42
;
then
sqrt (|.qz.| ^2 ) = |.q.|
by SQUARE_1:89;
then A43:
|.qz.| = |.q.|
by SQUARE_1:89;
|.(- q).| < r
by A25, EUCLID:31;
then
|.q.| < r
by TOPRNS_1:27;
then
|.(- qz).| < r
by A43, TOPRNS_1:27;
then
|.((0. (TOP-REAL 2)) - qz).| < r
by EUCLID:31;
then
dist u0,
pz < r
by JGRAPH_1:45;
hence
z in W1
by METRIC_1:12;
verum end; end; end;
hence
z in W1
;
verum
end;
u0 in W1
by A18, GOBOARD6:4;
hence
ex
W being
Subset of
(TOP-REAL 2) st
(
0. (TOP-REAL 2) in W &
W is
open &
f .: W c= V )
by A19, A20, A21, XBOOLE_1:1;
verum
end;
A44:
D ` = {(0. (TOP-REAL 2))}
by JGRAPH_3:30;
then
ex h being Function of ((TOP-REAL 2) | D),((TOP-REAL 2) | D) st
( h = (cn -FanMorphN ) | D & h is continuous )
by A1, A2, Th76;
hence
ex h being Function of (TOP-REAL 2),(TOP-REAL 2) st
( h = cn -FanMorphN & h is continuous )
by A3, A44, A4, A15, JGRAPH_3:13; verum