let X, X1, Z, Z1 be set ; for f1, f2 being PartFunc of REAL,REAL st X c= dom f1 & X1 c= dom f2 & f1 | X is uniformly_continuous & f2 | X1 is uniformly_continuous & f1 | Z is bounded & f2 | Z1 is bounded holds
(f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1) is uniformly_continuous
let f1, f2 be PartFunc of REAL,REAL; ( X c= dom f1 & X1 c= dom f2 & f1 | X is uniformly_continuous & f2 | X1 is uniformly_continuous & f1 | Z is bounded & f2 | Z1 is bounded implies (f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1) is uniformly_continuous )
assume that
A1:
X c= dom f1
and
A2:
X1 c= dom f2
; ( not f1 | X is uniformly_continuous or not f2 | X1 is uniformly_continuous or not f1 | Z is bounded or not f2 | Z1 is bounded or (f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1) is uniformly_continuous )
assume that
A3:
f1 | X is uniformly_continuous
and
A4:
f2 | X1 is uniformly_continuous
and
A5:
f1 | Z is bounded
and
A6:
f2 | Z1 is bounded
; (f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1) is uniformly_continuous
consider x1 being Real such that
A7:
for r being object st r in Z /\ (dom f1) holds
|.(f1 . r).| <= x1
by A5, RFUNCT_1:73;
consider x2 being Real such that
A8:
for r being object st r in Z1 /\ (dom f2) holds
|.(f2 . r).| <= x2
by A6, RFUNCT_1:73;
reconsider x1 = x1, x2 = x2 as Real ;
set M1 = |.x1.| + 1;
set M2 = |.x2.| + 1;
set M = max ((|.x1.| + 1),(|.x2.| + 1));
A9:
now for r being Real st r in ((X /\ Z) /\ X1) /\ Z1 holds
( |.(f1 . r).| < max ((|.x1.| + 1),(|.x2.| + 1)) & |.(f2 . r).| < max ((|.x1.| + 1),(|.x2.| + 1)) )let r be
Real;
( r in ((X /\ Z) /\ X1) /\ Z1 implies ( |.(f1 . r).| < max ((|.x1.| + 1),(|.x2.| + 1)) & |.(f2 . r).| < max ((|.x1.| + 1),(|.x2.| + 1)) ) )A10:
|.x1.| + 1
<= max (
(|.x1.| + 1),
(|.x2.| + 1))
by XXREAL_0:25;
assume
r in ((X /\ Z) /\ X1) /\ Z1
;
( |.(f1 . r).| < max ((|.x1.| + 1),(|.x2.| + 1)) & |.(f2 . r).| < max ((|.x1.| + 1),(|.x2.| + 1)) )then A11:
r in (X /\ Z) /\ (X1 /\ Z1)
by XBOOLE_1:16;
then A12:
r in X /\ Z
by XBOOLE_0:def 4;
then A13:
r in Z
by XBOOLE_0:def 4;
r in X
by A12, XBOOLE_0:def 4;
then
r in Z /\ (dom f1)
by A1, A13, XBOOLE_0:def 4;
then A14:
|.(f1 . r).| <= x1
by A7;
x1 + 0 < |.x1.| + 1
by ABSVALUE:4, XREAL_1:8;
then
|.(f1 . r).| < |.x1.| + 1
by A14, XXREAL_0:2;
hence
|.(f1 . r).| < max (
(|.x1.| + 1),
(|.x2.| + 1))
by A10, XXREAL_0:2;
|.(f2 . r).| < max ((|.x1.| + 1),(|.x2.| + 1))A15:
|.x2.| + 1
<= max (
(|.x1.| + 1),
(|.x2.| + 1))
by XXREAL_0:25;
A16:
r in X1 /\ Z1
by A11, XBOOLE_0:def 4;
then A17:
r in Z1
by XBOOLE_0:def 4;
r in X1
by A16, XBOOLE_0:def 4;
then
r in Z1 /\ (dom f2)
by A2, A17, XBOOLE_0:def 4;
then A18:
|.(f2 . r).| <= x2
by A8;
x2 + 0 < |.x2.| + 1
by ABSVALUE:4, XREAL_1:8;
then
|.(f2 . r).| < |.x2.| + 1
by A18, XXREAL_0:2;
hence
|.(f2 . r).| < max (
(|.x1.| + 1),
(|.x2.| + 1))
by A15, XXREAL_0:2;
verum end;
A19:
0 + 0 < |.x2.| + 1
by COMPLEX1:46, XREAL_1:8;
0 + 0 < |.x1.| + 1
by COMPLEX1:46, XREAL_1:8;
then A20:
0 < max ((|.x1.| + 1),(|.x2.| + 1))
by A19, XXREAL_0:16;
then A21:
0 < 2 * (max ((|.x1.| + 1),(|.x2.| + 1)))
by XREAL_1:129;
for r being Real st 0 < r holds
ex s being Real st
( 0 < s & ( for x1, x2 being Real st x1 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & x2 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & |.(x1 - x2).| < s holds
|.(((f1 (#) f2) . x1) - ((f1 (#) f2) . x2)).| < r ) )
proof
let r be
Real;
( 0 < r implies ex s being Real st
( 0 < s & ( for x1, x2 being Real st x1 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & x2 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & |.(x1 - x2).| < s holds
|.(((f1 (#) f2) . x1) - ((f1 (#) f2) . x2)).| < r ) ) )
assume
0 < r
;
ex s being Real st
( 0 < s & ( for x1, x2 being Real st x1 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & x2 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & |.(x1 - x2).| < s holds
|.(((f1 (#) f2) . x1) - ((f1 (#) f2) . x2)).| < r ) )
then A22:
0 < r / (2 * (max ((|.x1.| + 1),(|.x2.| + 1))))
by A21, XREAL_1:139;
then consider s being
Real such that A23:
0 < s
and A24:
for
x1,
x2 being
Real st
x1 in dom (f1 | X) &
x2 in dom (f1 | X) &
|.(x1 - x2).| < s holds
|.((f1 . x1) - (f1 . x2)).| < r / (2 * (max ((|.x1.| + 1),(|.x2.| + 1))))
by A3, Th1;
consider g being
Real such that A25:
0 < g
and A26:
for
x1,
x2 being
Real st
x1 in dom (f2 | X1) &
x2 in dom (f2 | X1) &
|.(x1 - x2).| < g holds
|.((f2 . x1) - (f2 . x2)).| < r / (2 * (max ((|.x1.| + 1),(|.x2.| + 1))))
by A4, A22, Th1;
take p =
min (
s,
g);
( 0 < p & ( for x1, x2 being Real st x1 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & x2 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & |.(x1 - x2).| < p holds
|.(((f1 (#) f2) . x1) - ((f1 (#) f2) . x2)).| < r ) )
thus
0 < p
by A23, A25, XXREAL_0:15;
for x1, x2 being Real st x1 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & x2 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & |.(x1 - x2).| < p holds
|.(((f1 (#) f2) . x1) - ((f1 (#) f2) . x2)).| < r
let y1,
y2 be
Real;
( y1 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & y2 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1)) & |.(y1 - y2).| < p implies |.(((f1 (#) f2) . y1) - ((f1 (#) f2) . y2)).| < r )
assume that A27:
y1 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1))
and A28:
y2 in dom ((f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1))
;
( not |.(y1 - y2).| < p or |.(((f1 (#) f2) . y1) - ((f1 (#) f2) . y2)).| < r )
assume A29:
|.(y1 - y2).| < p
;
|.(((f1 (#) f2) . y1) - ((f1 (#) f2) . y2)).| < r
A30:
y2 in ((X /\ Z) /\ X1) /\ Z1
by A28, RELAT_1:57;
then A31:
y2 in (X /\ Z) /\ (X1 /\ Z1)
by XBOOLE_1:16;
then
y2 in X /\ Z
by XBOOLE_0:def 4;
then
y2 in X
by XBOOLE_0:def 4;
then A32:
y2 in dom (f1 | X)
by A1, RELAT_1:62;
A33:
y1 in ((X /\ Z) /\ X1) /\ Z1
by A27, RELAT_1:57;
then A34:
y1 in (X /\ Z) /\ (X1 /\ Z1)
by XBOOLE_1:16;
then
y1 in X /\ Z
by XBOOLE_0:def 4;
then
y1 in X
by XBOOLE_0:def 4;
then A35:
y1 in dom (f1 | X)
by A1, RELAT_1:62;
y2 in X1 /\ Z1
by A31, XBOOLE_0:def 4;
then
y2 in X1
by XBOOLE_0:def 4;
then A36:
y2 in dom (f2 | X1)
by A2, RELAT_1:62;
y1 in X1 /\ Z1
by A34, XBOOLE_0:def 4;
then
y1 in X1
by XBOOLE_0:def 4;
then A37:
y1 in dom (f2 | X1)
by A2, RELAT_1:62;
p <= g
by XXREAL_0:17;
then
|.(y1 - y2).| < g
by A29, XXREAL_0:2;
then A38:
|.((f2 . y1) - (f2 . y2)).| < r / (2 * (max ((|.x1.| + 1),(|.x2.| + 1))))
by A26, A37, A36;
|.(((f1 (#) f2) . y1) - ((f1 (#) f2) . y2)).| =
|.(((f1 . y1) * (f2 . y1)) - ((f1 (#) f2) . y2)).|
by VALUED_1:5
.=
|.((((f1 . y1) * (f2 . y1)) + (((f1 . y1) * (f2 . y2)) - ((f1 . y1) * (f2 . y2)))) - ((f1 . y2) * (f2 . y2))).|
by VALUED_1:5
.=
|.(((f1 . y1) * ((f2 . y1) - (f2 . y2))) + (((f1 . y1) - (f1 . y2)) * (f2 . y2))).|
;
then A39:
|.(((f1 (#) f2) . y1) - ((f1 (#) f2) . y2)).| <= |.((f1 . y1) * ((f2 . y1) - (f2 . y2))).| + |.(((f1 . y1) - (f1 . y2)) * (f2 . y2)).|
by COMPLEX1:56;
A40:
|.((f1 . y1) * ((f2 . y1) - (f2 . y2))).| = |.(f1 . y1).| * |.((f2 . y1) - (f2 . y2)).|
by COMPLEX1:65;
A41:
|.(f2 . y2).| < max (
(|.x1.| + 1),
(|.x2.| + 1))
by A9, A30;
A42:
0 <= |.(f2 . y2).|
by COMPLEX1:46;
A43:
0 <= |.((f1 . y1) - (f1 . y2)).|
by COMPLEX1:46;
A44:
|.(((f1 . y1) - (f1 . y2)) * (f2 . y2)).| = |.(f2 . y2).| * |.((f1 . y1) - (f1 . y2)).|
by COMPLEX1:65;
p <= s
by XXREAL_0:17;
then
|.(y1 - y2).| < s
by A29, XXREAL_0:2;
then
|.((f1 . y1) - (f1 . y2)).| < r / (2 * (max ((|.x1.| + 1),(|.x2.| + 1))))
by A24, A35, A32;
then A45:
|.(((f1 . y1) - (f1 . y2)) * (f2 . y2)).| < (max ((|.x1.| + 1),(|.x2.| + 1))) * (r / (2 * (max ((|.x1.| + 1),(|.x2.| + 1)))))
by A44, A41, A43, A42, XREAL_1:96;
A46:
0 <= |.(f1 . y1).|
by COMPLEX1:46;
A47:
0 <= |.((f2 . y1) - (f2 . y2)).|
by COMPLEX1:46;
|.(f1 . y1).| < max (
(|.x1.| + 1),
(|.x2.| + 1))
by A9, A33;
then
|.((f1 . y1) * ((f2 . y1) - (f2 . y2))).| < (max ((|.x1.| + 1),(|.x2.| + 1))) * (r / (2 * (max ((|.x1.| + 1),(|.x2.| + 1)))))
by A40, A38, A47, A46, XREAL_1:96;
then A48:
|.((f1 . y1) * ((f2 . y1) - (f2 . y2))).| + |.(((f1 . y1) - (f1 . y2)) * (f2 . y2)).| < ((max ((|.x1.| + 1),(|.x2.| + 1))) * (r / (2 * (max ((|.x1.| + 1),(|.x2.| + 1)))))) + ((max ((|.x1.| + 1),(|.x2.| + 1))) * (r / (2 * (max ((|.x1.| + 1),(|.x2.| + 1))))))
by A45, XREAL_1:8;
((max ((|.x1.| + 1),(|.x2.| + 1))) * (r / (2 * (max ((|.x1.| + 1),(|.x2.| + 1)))))) + ((max ((|.x1.| + 1),(|.x2.| + 1))) * (r / (2 * (max ((|.x1.| + 1),(|.x2.| + 1)))))) =
(max ((|.x1.| + 1),(|.x2.| + 1))) * ((r / ((max ((|.x1.| + 1),(|.x2.| + 1))) * 2)) + (r / ((max ((|.x1.| + 1),(|.x2.| + 1))) * 2)))
.=
(r / (max ((|.x1.| + 1),(|.x2.| + 1)))) * (max ((|.x1.| + 1),(|.x2.| + 1)))
by XCMPLX_1:118
.=
r
by A20, XCMPLX_1:87
;
hence
|.(((f1 (#) f2) . y1) - ((f1 (#) f2) . y2)).| < r
by A39, A48, XXREAL_0:2;
verum
end;
hence
(f1 (#) f2) | (((X /\ Z) /\ X1) /\ Z1) is uniformly_continuous
by Th1; verum