let f be PartFunc of [:[:RNS_Real,RNS_Real:],RNS_Real:],RNS_Real; for g being PartFunc of [:[:REAL,REAL:],REAL:],REAL
for x, y being Element of REAL st f is_uniformly_continuous_on dom f & f = g holds
ProjPMap1 (g,[x,y]) is uniformly_continuous
let g be PartFunc of [:[:REAL,REAL:],REAL:],REAL; for x, y being Element of REAL st f is_uniformly_continuous_on dom f & f = g holds
ProjPMap1 (g,[x,y]) is uniformly_continuous
let x, y be Element of REAL ; ( f is_uniformly_continuous_on dom f & f = g implies ProjPMap1 (g,[x,y]) is uniformly_continuous )
assume that
A1:
f is_uniformly_continuous_on dom f
and
A2:
f = g
; ProjPMap1 (g,[x,y]) is uniformly_continuous
for r being Real st 0 < r holds
ex s being Real st
( 0 < s & ( for z1, z2 being Real st z1 in dom (ProjPMap1 (g,[x,y])) & z2 in dom (ProjPMap1 (g,[x,y])) & |.(z1 - z2).| < s holds
|.(((ProjPMap1 (g,[x,y])) . z1) - ((ProjPMap1 (g,[x,y])) . z2)).| < r ) )
proof
let r be
Real;
( 0 < r implies ex s being Real st
( 0 < s & ( for z1, z2 being Real st z1 in dom (ProjPMap1 (g,[x,y])) & z2 in dom (ProjPMap1 (g,[x,y])) & |.(z1 - z2).| < s holds
|.(((ProjPMap1 (g,[x,y])) . z1) - ((ProjPMap1 (g,[x,y])) . z2)).| < r ) ) )
assume
0 < r
;
ex s being Real st
( 0 < s & ( for z1, z2 being Real st z1 in dom (ProjPMap1 (g,[x,y])) & z2 in dom (ProjPMap1 (g,[x,y])) & |.(z1 - z2).| < s holds
|.(((ProjPMap1 (g,[x,y])) . z1) - ((ProjPMap1 (g,[x,y])) . z2)).| < r ) )
then consider s being
Real such that A3:
0 < s
and A4:
for
p1,
p2 being
Point of
[:[:RNS_Real,RNS_Real:],RNS_Real:] st
p1 in dom f &
p2 in dom f &
||.(p1 - p2).|| < s holds
||.((f /. p1) - (f /. p2)).|| < r
by A1;
now for z1, z2 being Real st z1 in dom (ProjPMap1 (g,[x,y])) & z2 in dom (ProjPMap1 (g,[x,y])) & |.(z1 - z2).| < s holds
|.(((ProjPMap1 (g,[x,y])) . z1) - ((ProjPMap1 (g,[x,y])) . z2)).| < rlet z1,
z2 be
Real;
( z1 in dom (ProjPMap1 (g,[x,y])) & z2 in dom (ProjPMap1 (g,[x,y])) & |.(z1 - z2).| < s implies |.(((ProjPMap1 (g,[x,y])) . z1) - ((ProjPMap1 (g,[x,y])) . z2)).| < r )assume that A5:
z1 in dom (ProjPMap1 (g,[x,y]))
and A6:
z2 in dom (ProjPMap1 (g,[x,y]))
and A7:
|.(z1 - z2).| < s
;
|.(((ProjPMap1 (g,[x,y])) . z1) - ((ProjPMap1 (g,[x,y])) . z2)).| < rA8:
X-section (
(dom g),
[x,y])
= { z where z is Element of REAL : [[x,y],z] in dom g }
by MEASUR11:def 4;
A9:
(
z1 in X-section (
(dom g),
[x,y]) &
z2 in X-section (
(dom g),
[x,y]) )
by A5, A6, MESFUN12:def 3;
then A10:
ex
z being
Element of
REAL st
(
z = z1 &
[[x,y],z] in dom g )
by A8;
A11:
ex
z being
Element of
REAL st
(
z = z2 &
[[x,y],z] in dom g )
by A8, A9;
reconsider xx =
x,
yy =
y as
Point of
RNS_Real ;
reconsider zz1 =
z1 as
Point of
RNS_Real by XREAL_0:def 1;
reconsider zz2 =
z2 as
Point of
RNS_Real by XREAL_0:def 1;
reconsider p1 =
[xx,yy,zz1],
p2 =
[xx,yy,zz2] as
Point of
[:[:RNS_Real,RNS_Real:],RNS_Real:] ;
A12:
zz1 - zz2 = z1 - z2
by DUALSP03:4;
p1 - p2 = [xx,yy,zz1] + [(- xx),(- yy),(- zz2)]
by PRVECT_4:9;
then
p1 - p2 = [(xx - xx),(yy - yy),(zz1 - zz2)]
by PRVECT_4:9;
then
p1 - p2 = [(0. RNS_Real),(yy - yy),(zz1 - zz2)]
by RLVECT_1:15;
then
p1 - p2 = [(0. RNS_Real),(0. RNS_Real),(zz1 - zz2)]
by RLVECT_1:15;
then
||.(p1 - p2).|| = sqrt (((||.(0. RNS_Real).|| ^2) + (||.(0. RNS_Real).|| ^2)) + (||.(zz1 - zz2).|| ^2))
by PRVECT_4:9;
then
||.(p1 - p2).|| = ||.(zz1 - zz2).||
by SQUARE_1:22;
then
||.(p1 - p2).|| = |.(z1 - z2).|
by A12, EUCLID:def 2;
then A13:
||.((f /. p1) - (f /. p2)).|| < r
by A4, A7, A2, A10, A11;
(
(ProjPMap1 (g,[x,y])) . z1 = g . (
[x,y],
z1) &
(ProjPMap1 (g,[x,y])) . z2 = g . (
[x,y],
z2) )
by A10, A11, MESFUN12:def 3;
then
(
(ProjPMap1 (g,[x,y])) . z1 = f /. p1 &
(ProjPMap1 (g,[x,y])) . z2 = f /. p2 )
by A2, A10, A11, PARTFUN1:def 6;
then
((ProjPMap1 (g,[x,y])) . z1) - ((ProjPMap1 (g,[x,y])) . z2) = (f /. p1) - (f /. p2)
by DUALSP03:4;
hence
|.(((ProjPMap1 (g,[x,y])) . z1) - ((ProjPMap1 (g,[x,y])) . z2)).| < r
by A13, EUCLID:def 2;
verum end;
hence
ex
s being
Real st
(
0 < s & ( for
z1,
z2 being
Real st
z1 in dom (ProjPMap1 (g,[x,y])) &
z2 in dom (ProjPMap1 (g,[x,y])) &
|.(z1 - z2).| < s holds
|.(((ProjPMap1 (g,[x,y])) . z1) - ((ProjPMap1 (g,[x,y])) . z2)).| < r ) )
by A3;
verum
end;
hence
ProjPMap1 (g,[x,y]) is uniformly_continuous
by FCONT_2:def 1; verum