reconsider D = NonZero (TOP-REAL 2) as non empty Subset of (TOP-REAL 2) by JGRAPH_2:19;
let sn be Real; ( - 1 < sn & sn < 1 implies ex h being Function of (TOP-REAL 2),(TOP-REAL 2) st
( h = sn -FanMorphW & h is continuous ) )
assume that
A1:
- 1 < sn
and
A2:
sn < 1
; ex h being Function of (TOP-REAL 2),(TOP-REAL 2) st
( h = sn -FanMorphW & h is continuous )
reconsider f = sn -FanMorphW as Function of (TOP-REAL 2),(TOP-REAL 2) ;
A3:
f . (0. (TOP-REAL 2)) = 0. (TOP-REAL 2)
by Th23, JGRAPH_2:11;
A4:
for p being Point of ((TOP-REAL 2) | D) holds f . p <> f . (0. (TOP-REAL 2))
A17:
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 A18:
f . (0. (TOP-REAL 2)) in V
and A19:
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 A19, Lm11, PRE_TOPC:60;
then consider r being
real number such that A20:
r > 0
and A21:
Ball u0,
r c= V
by A3, A18, 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) ;
A22:
W1 is
open
by GOBOARD6:6;
A23:
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 A24:
y in dom f
and A25:
y in W1
and A26:
z = f . y
by FUNCT_1:def 12;
z in rng f
by A24, A26, FUNCT_1:def 5;
then reconsider qz =
z as
Point of
(TOP-REAL 2) ;
reconsider pz =
qz as
Point of
(Euclid 2) by EUCLID:71;
reconsider q =
y as
Point of
(TOP-REAL 2) by A24;
reconsider qy =
q as
Point of
(Euclid 2) by EUCLID:71;
dist u0,
qy < r
by A25, METRIC_1:12;
then A27:
|.((0. (TOP-REAL 2)) - q).| < r
by JGRAPH_1:45;
per cases
( q `1 >= 0 or ( q <> 0. (TOP-REAL 2) & (q `2 ) / |.q.| >= sn & q `1 <= 0 ) or ( q <> 0. (TOP-REAL 2) & (q `2 ) / |.q.| < sn & q `1 <= 0 ) )
by JGRAPH_2:11;
suppose A28:
(
q <> 0. (TOP-REAL 2) &
(q `2 ) / |.q.| >= sn &
q `1 <= 0 )
;
z in W1then A29:
((q `2 ) / |.q.|) - sn >= 0
by XREAL_1:50;
0 <= (q `1 ) ^2
by XREAL_1:65;
then
(
|.q.| ^2 = ((q `1 ) ^2 ) + ((q `2 ) ^2 ) &
0 + ((q `2 ) ^2 ) <= ((q `1 ) ^2 ) + ((q `2 ) ^2 ) )
by JGRAPH_3:10, XREAL_1:9;
then A30:
((q `2 ) ^2 ) / (|.q.| ^2 ) <= (|.q.| ^2 ) / (|.q.| ^2 )
by XREAL_1:74;
A31:
1
- sn > 0
by A2, XREAL_1:151;
|.q.| <> 0
by A28, TOPRNS_1:25;
then
|.q.| ^2 > 0
by SQUARE_1:74;
then
((q `2 ) ^2 ) / (|.q.| ^2 ) <= 1
by A30, XCMPLX_1:60;
then
((q `2 ) / |.q.|) ^2 <= 1
by XCMPLX_1:77;
then
1
>= (q `2 ) / |.q.|
by SQUARE_1:121;
then
1
- sn >= ((q `2 ) / |.q.|) - sn
by XREAL_1:11;
then
- (1 - sn) <= - (((q `2 ) / |.q.|) - sn)
by XREAL_1:26;
then
(- (1 - sn)) / (1 - sn) <= (- (((q `2 ) / |.q.|) - sn)) / (1 - sn)
by A31, XREAL_1:74;
then
- 1
<= (- (((q `2 ) / |.q.|) - sn)) / (1 - sn)
by A31, XCMPLX_1:198;
then
((- (((q `2 ) / |.q.|) - sn)) / (1 - sn)) ^2 <= 1
^2
by A31, A29, SQUARE_1:119;
then
1
- (((- (((q `2 ) / |.q.|) - sn)) / (1 - sn)) ^2 ) >= 0
by XREAL_1:50;
then A32:
1
- ((- ((((q `2 ) / |.q.|) - sn) / (1 - sn))) ^2 ) >= 0
by XCMPLX_1:188;
A33:
(sn -FanMorphW ) . q = |[(|.q.| * (- (sqrt (1 - (((((q `2 ) / |.q.|) - sn) / (1 - sn)) ^2 ))))),(|.q.| * ((((q `2 ) / |.q.|) - sn) / (1 - sn)))]|
by A1, A2, A28, Th25;
then A34:
qz `2 = |.q.| * ((((q `2 ) / |.q.|) - sn) / (1 - sn))
by A26, EUCLID:56;
qz `1 = |.q.| * (- (sqrt (1 - (((((q `2 ) / |.q.|) - sn) / (1 - sn)) ^2 ))))
by A26, A33, EUCLID:56;
then A35:
(qz `1 ) ^2 =
(|.q.| ^2 ) * ((sqrt (1 - (((((q `2 ) / |.q.|) - sn) / (1 - sn)) ^2 ))) ^2 )
.=
(|.q.| ^2 ) * (1 - (((((q `2 ) / |.q.|) - sn) / (1 - sn)) ^2 ))
by A32, SQUARE_1:def 4
;
|.qz.| ^2 =
((qz `1 ) ^2 ) + ((qz `2 ) ^2 )
by JGRAPH_3:10
.=
|.q.| ^2
by A34, A35
;
then
sqrt (|.qz.| ^2 ) = |.q.|
by SQUARE_1:89;
then A36:
|.qz.| = |.q.|
by SQUARE_1:89;
|.(- q).| < r
by A27, EUCLID:31;
then
|.q.| < r
by TOPRNS_1:27;
then
|.(- qz).| < r
by A36, 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; suppose A37:
(
q <> 0. (TOP-REAL 2) &
(q `2 ) / |.q.| < sn &
q `1 <= 0 )
;
z in W1
0 <= (q `1 ) ^2
by XREAL_1:65;
then
(
|.q.| ^2 = ((q `1 ) ^2 ) + ((q `2 ) ^2 ) &
0 + ((q `2 ) ^2 ) <= ((q `1 ) ^2 ) + ((q `2 ) ^2 ) )
by JGRAPH_3:10, XREAL_1:9;
then A38:
((q `2 ) ^2 ) / (|.q.| ^2 ) <= (|.q.| ^2 ) / (|.q.| ^2 )
by XREAL_1:74;
A39:
1
+ sn > 0
by A1, XREAL_1:150;
|.q.| <> 0
by A37, TOPRNS_1:25;
then
|.q.| ^2 > 0
by SQUARE_1:74;
then
((q `2 ) ^2 ) / (|.q.| ^2 ) <= 1
by A38, XCMPLX_1:60;
then
((q `2 ) / |.q.|) ^2 <= 1
by XCMPLX_1:77;
then
- 1
<= (q `2 ) / |.q.|
by SQUARE_1:121;
then
- (- 1) >= - ((q `2 ) / |.q.|)
by XREAL_1:26;
then
1
+ sn >= (- ((q `2 ) / |.q.|)) + sn
by XREAL_1:9;
then A40:
(- (((q `2 ) / |.q.|) - sn)) / (1 + sn) <= 1
by A39, XREAL_1:187;
sn - ((q `2 ) / |.q.|) >= 0
by A37, XREAL_1:50;
then
- 1
<= (- (((q `2 ) / |.q.|) - sn)) / (1 + sn)
by A39;
then
((- (((q `2 ) / |.q.|) - sn)) / (1 + sn)) ^2 <= 1
^2
by A40, SQUARE_1:119;
then
1
- (((- (((q `2 ) / |.q.|) - sn)) / (1 + sn)) ^2 ) >= 0
by XREAL_1:50;
then A41:
1
- ((- ((((q `2 ) / |.q.|) - sn) / (1 + sn))) ^2 ) >= 0
by XCMPLX_1:188;
A42:
(sn -FanMorphW ) . q = |[(|.q.| * (- (sqrt (1 - (((((q `2 ) / |.q.|) - sn) / (1 + sn)) ^2 ))))),(|.q.| * ((((q `2 ) / |.q.|) - sn) / (1 + sn)))]|
by A1, A2, A37, Th25;
then A43:
qz `2 = |.q.| * ((((q `2 ) / |.q.|) - sn) / (1 + sn))
by A26, EUCLID:56;
qz `1 = |.q.| * (- (sqrt (1 - (((((q `2 ) / |.q.|) - sn) / (1 + sn)) ^2 ))))
by A26, A42, EUCLID:56;
then A44:
(qz `1 ) ^2 =
(|.q.| ^2 ) * ((sqrt (1 - (((((q `2 ) / |.q.|) - sn) / (1 + sn)) ^2 ))) ^2 )
.=
(|.q.| ^2 ) * (1 - (((((q `2 ) / |.q.|) - sn) / (1 + sn)) ^2 ))
by A41, SQUARE_1:def 4
;
|.qz.| ^2 =
((qz `1 ) ^2 ) + ((qz `2 ) ^2 )
by JGRAPH_3:10
.=
|.q.| ^2
by A43, A44
;
then
sqrt (|.qz.| ^2 ) = |.q.|
by SQUARE_1:89;
then A45:
|.qz.| = |.q.|
by SQUARE_1:89;
|.(- q).| < r
by A27, EUCLID:31;
then
|.q.| < r
by TOPRNS_1:27;
then
|.(- qz).| < r
by A45, 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;
u0 in W1
by A20, 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 A21, A22, A23, XBOOLE_1:1;
verum
end;
A46:
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 = (sn -FanMorphW ) | D & h is continuous )
by A1, A2, Th43;
hence
ex h being Function of (TOP-REAL 2),(TOP-REAL 2) st
( h = sn -FanMorphW & h is continuous )
by A3, A46, A4, A17, JGRAPH_3:13; verum