let f be PartFunc of [:RNS_Real,RNS_Real:],RNS_Real; for g being PartFunc of [:REAL,REAL:],REAL
for t being Element of REAL st f is_continuous_on dom f & f = g holds
( ProjPMap1 (g,t) is continuous & ProjPMap2 (g,t) is continuous )
let g be PartFunc of [:REAL,REAL:],REAL; for t being Element of REAL st f is_continuous_on dom f & f = g holds
( ProjPMap1 (g,t) is continuous & ProjPMap2 (g,t) is continuous )
let t be Element of REAL ; ( f is_continuous_on dom f & f = g implies ( ProjPMap1 (g,t) is continuous & ProjPMap2 (g,t) is continuous ) )
assume that
A1:
f is_continuous_on dom f
and
A2:
f = g
; ( ProjPMap1 (g,t) is continuous & ProjPMap2 (g,t) is continuous )
for y0 being Real st y0 in dom (ProjPMap1 (g,t)) holds
ProjPMap1 (g,t) is_continuous_in y0
proof
let y0 be
Real;
( y0 in dom (ProjPMap1 (g,t)) implies ProjPMap1 (g,t) is_continuous_in y0 )
assume
y0 in dom (ProjPMap1 (g,t))
;
ProjPMap1 (g,t) is_continuous_in y0
then A3:
y0 in X-section (
(dom g),
t)
by MESFUN12:def 3;
A4:
X-section (
(dom g),
t)
= { y where y is Element of REAL : [t,y] in dom g }
by MEASUR11:def 4;
then A5:
ex
y being
Element of
REAL st
(
y = y0 &
[t,y] in dom g )
by A3;
reconsider xx =
t as
Point of
RNS_Real ;
reconsider yy0 =
y0 as
Point of
RNS_Real by XREAL_0:def 1;
reconsider p0 =
[xx,yy0] as
Point of
[:RNS_Real,RNS_Real:] ;
for
r being
Real st
0 < r holds
ex
s being
Real st
(
0 < s & ( for
y1 being
Real st
y1 in dom (ProjPMap1 (g,t)) &
|.(y1 - y0).| < s holds
|.(((ProjPMap1 (g,t)) . y1) - ((ProjPMap1 (g,t)) . y0)).| < r ) )
proof
let r be
Real;
( 0 < r implies ex s being Real st
( 0 < s & ( for y1 being Real st y1 in dom (ProjPMap1 (g,t)) & |.(y1 - y0).| < s holds
|.(((ProjPMap1 (g,t)) . y1) - ((ProjPMap1 (g,t)) . y0)).| < r ) ) )
assume
0 < r
;
ex s being Real st
( 0 < s & ( for y1 being Real st y1 in dom (ProjPMap1 (g,t)) & |.(y1 - y0).| < s holds
|.(((ProjPMap1 (g,t)) . y1) - ((ProjPMap1 (g,t)) . y0)).| < r ) )
then consider s being
Real such that A6:
0 < s
and A7:
for
p1 being
Point of
[:RNS_Real,RNS_Real:] st
p1 in dom f &
||.(p1 - p0).|| < s holds
||.((f /. p1) - (f /. p0)).|| < r
by A1, A2, A5, NFCONT_1:19;
now for y1 being Real st y1 in dom (ProjPMap1 (g,t)) & |.(y1 - y0).| < s holds
|.(((ProjPMap1 (g,t)) . y1) - ((ProjPMap1 (g,t)) . y0)).| < rlet y1 be
Real;
( y1 in dom (ProjPMap1 (g,t)) & |.(y1 - y0).| < s implies |.(((ProjPMap1 (g,t)) . y1) - ((ProjPMap1 (g,t)) . y0)).| < r )assume that A8:
y1 in dom (ProjPMap1 (g,t))
and A9:
|.(y1 - y0).| < s
;
|.(((ProjPMap1 (g,t)) . y1) - ((ProjPMap1 (g,t)) . y0)).| < r
y1 in X-section (
(dom g),
t)
by A8, MESFUN12:def 3;
then A10:
ex
y being
Element of
REAL st
(
y = y1 &
[t,y] in dom g )
by A4;
reconsider yy1 =
y1 as
Point of
RNS_Real by XREAL_0:def 1;
reconsider p1 =
[xx,yy1] as
Point of
[:RNS_Real,RNS_Real:] ;
A11:
yy1 - yy0 = y1 - y0
by DUALSP03:4;
p1 - p0 = [xx,yy1] + [(- xx),(- yy0)]
by PRVECT_3:18;
then
p1 - p0 = [(xx - xx),(yy1 - yy0)]
by PRVECT_3:18;
then
p1 - p0 = [(0. RNS_Real),(yy1 - yy0)]
by RLVECT_1:15;
then
||.(p1 - p0).|| = sqrt ((||.(0. RNS_Real).|| ^2) + (||.(yy1 - yy0).|| ^2))
by NDIFF_8:1;
then
||.(p1 - p0).|| = ||.(yy1 - yy0).||
by SQUARE_1:22;
then
||.(p1 - p0).|| = |.(y1 - y0).|
by A11, EUCLID:def 2;
then A12:
||.((f /. p1) - (f /. p0)).|| < r
by A9, A2, A10, A7;
(
(ProjPMap1 (g,t)) . y1 = g . (
t,
y1) &
(ProjPMap1 (g,t)) . y0 = g . (
t,
y0) )
by A5, A10, MESFUN12:def 3;
then
(
(ProjPMap1 (g,t)) . y1 = f /. p1 &
(ProjPMap1 (g,t)) . y0 = f /. p0 )
by A2, A5, A10, PARTFUN1:def 6;
then
((ProjPMap1 (g,t)) . y1) - ((ProjPMap1 (g,t)) . y0) = (f /. p1) - (f /. p0)
by DUALSP03:4;
hence
|.(((ProjPMap1 (g,t)) . y1) - ((ProjPMap1 (g,t)) . y0)).| < r
by A12, EUCLID:def 2;
verum end;
hence
ex
s being
Real st
(
0 < s & ( for
y1 being
Real st
y1 in dom (ProjPMap1 (g,t)) &
|.(y1 - y0).| < s holds
|.(((ProjPMap1 (g,t)) . y1) - ((ProjPMap1 (g,t)) . y0)).| < r ) )
by A6;
verum
end;
hence
ProjPMap1 (
g,
t)
is_continuous_in y0
by FCONT_1:3;
verum
end;
hence
ProjPMap1 (g,t) is continuous
; ProjPMap2 (g,t) is continuous
for x0 being Real st x0 in dom (ProjPMap2 (g,t)) holds
ProjPMap2 (g,t) is_continuous_in x0
proof
let x0 be
Real;
( x0 in dom (ProjPMap2 (g,t)) implies ProjPMap2 (g,t) is_continuous_in x0 )
assume
x0 in dom (ProjPMap2 (g,t))
;
ProjPMap2 (g,t) is_continuous_in x0
then A13:
x0 in Y-section (
(dom g),
t)
by MESFUN12:def 4;
A14:
Y-section (
(dom g),
t)
= { x where x is Element of REAL : [x,t] in dom g }
by MEASUR11:def 5;
then A15:
ex
x being
Element of
REAL st
(
x = x0 &
[x,t] in dom g )
by A13;
reconsider yy =
t as
Point of
RNS_Real ;
reconsider xx0 =
x0 as
Point of
RNS_Real by XREAL_0:def 1;
reconsider p0 =
[xx0,yy] as
Point of
[:RNS_Real,RNS_Real:] ;
for
r being
Real st
0 < r holds
ex
s being
Real st
(
0 < s & ( for
x1 being
Real st
x1 in dom (ProjPMap2 (g,t)) &
|.(x1 - x0).| < s holds
|.(((ProjPMap2 (g,t)) . x1) - ((ProjPMap2 (g,t)) . x0)).| < r ) )
proof
let r be
Real;
( 0 < r implies ex s being Real st
( 0 < s & ( for x1 being Real st x1 in dom (ProjPMap2 (g,t)) & |.(x1 - x0).| < s holds
|.(((ProjPMap2 (g,t)) . x1) - ((ProjPMap2 (g,t)) . x0)).| < r ) ) )
assume
0 < r
;
ex s being Real st
( 0 < s & ( for x1 being Real st x1 in dom (ProjPMap2 (g,t)) & |.(x1 - x0).| < s holds
|.(((ProjPMap2 (g,t)) . x1) - ((ProjPMap2 (g,t)) . x0)).| < r ) )
then consider s being
Real such that A16:
0 < s
and A17:
for
p1 being
Point of
[:RNS_Real,RNS_Real:] st
p1 in dom f &
||.(p1 - p0).|| < s holds
||.((f /. p1) - (f /. p0)).|| < r
by A1, A2, A15, NFCONT_1:19;
now for x1 being Real st x1 in dom (ProjPMap2 (g,t)) & |.(x1 - x0).| < s holds
|.(((ProjPMap2 (g,t)) . x1) - ((ProjPMap2 (g,t)) . x0)).| < rlet x1 be
Real;
( x1 in dom (ProjPMap2 (g,t)) & |.(x1 - x0).| < s implies |.(((ProjPMap2 (g,t)) . x1) - ((ProjPMap2 (g,t)) . x0)).| < r )assume that A18:
x1 in dom (ProjPMap2 (g,t))
and A19:
|.(x1 - x0).| < s
;
|.(((ProjPMap2 (g,t)) . x1) - ((ProjPMap2 (g,t)) . x0)).| < r
x1 in Y-section (
(dom g),
t)
by A18, MESFUN12:def 4;
then A20:
ex
x being
Element of
REAL st
(
x = x1 &
[x,t] in dom g )
by A14;
reconsider xx1 =
x1 as
Point of
RNS_Real by XREAL_0:def 1;
reconsider p1 =
[xx1,yy] as
Point of
[:RNS_Real,RNS_Real:] ;
A21:
xx1 - xx0 = x1 - x0
by DUALSP03:4;
p1 - p0 = [xx1,yy] + [(- xx0),(- yy)]
by PRVECT_3:18;
then
p1 - p0 = [(xx1 - xx0),(yy - yy)]
by PRVECT_3:18;
then
p1 - p0 = [(xx1 - xx0),(0. RNS_Real)]
by RLVECT_1:15;
then
||.(p1 - p0).|| = sqrt ((||.(0. RNS_Real).|| ^2) + (||.(xx1 - xx0).|| ^2))
by NDIFF_8:1;
then
||.(p1 - p0).|| = ||.(xx1 - xx0).||
by SQUARE_1:22;
then
||.(p1 - p0).|| = |.(x1 - x0).|
by A21, EUCLID:def 2;
then A22:
||.((f /. p1) - (f /. p0)).|| < r
by A19, A2, A20, A17;
(
(ProjPMap2 (g,t)) . x1 = g . (
x1,
t) &
(ProjPMap2 (g,t)) . x0 = g . (
x0,
t) )
by A15, A20, MESFUN12:def 4;
then
(
(ProjPMap2 (g,t)) . x1 = f /. p1 &
(ProjPMap2 (g,t)) . x0 = f /. p0 )
by A2, A15, A20, PARTFUN1:def 6;
then
((ProjPMap2 (g,t)) . x1) - ((ProjPMap2 (g,t)) . x0) = (f /. p1) - (f /. p0)
by DUALSP03:4;
hence
|.(((ProjPMap2 (g,t)) . x1) - ((ProjPMap2 (g,t)) . x0)).| < r
by A22, EUCLID:def 2;
verum end;
hence
ex
s being
Real st
(
0 < s & ( for
x1 being
Real st
x1 in dom (ProjPMap2 (g,t)) &
|.(x1 - x0).| < s holds
|.(((ProjPMap2 (g,t)) . x1) - ((ProjPMap2 (g,t)) . x0)).| < r ) )
by A16;
verum
end;
hence
ProjPMap2 (
g,
t)
is_continuous_in x0
by FCONT_1:3;
verum
end;
hence
ProjPMap2 (g,t) is continuous
; verum