let X be set ; for p being Real
for f being PartFunc of REAL,REAL st X c= dom f & f | X is uniformly_continuous holds
(p (#) f) | X is uniformly_continuous
let p be Real; for f being PartFunc of REAL,REAL st X c= dom f & f | X is uniformly_continuous holds
(p (#) f) | X is uniformly_continuous
let f be PartFunc of REAL,REAL; ( X c= dom f & f | X is uniformly_continuous implies (p (#) f) | X is uniformly_continuous )
assume
X c= dom f
; ( not f | X is uniformly_continuous or (p (#) f) | X is uniformly_continuous )
then A1:
X c= dom (p (#) f)
by VALUED_1:def 5;
assume A2:
f | X is uniformly_continuous
; (p (#) f) | X is uniformly_continuous
per cases
( p = 0 or p <> 0 )
;
suppose A3:
p = 0
;
(p (#) f) | X is uniformly_continuous now let r be
Real;
( 0 < r implies ex s being Real st
( 0 < s & ( for x1, x2 being Real st x1 in dom ((p (#) f) | X) & x2 in dom ((p (#) f) | X) & abs (x1 - x2) < s holds
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < r ) ) )assume A4:
0 < r
;
ex s being Real st
( 0 < s & ( for x1, x2 being Real st x1 in dom ((p (#) f) | X) & x2 in dom ((p (#) f) | X) & abs (x1 - x2) < s holds
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < r ) )then consider s being
Real such that A5:
0 < s
and
for
x1,
x2 being
Real st
x1 in dom (f | X) &
x2 in dom (f | X) &
abs (x1 - x2) < s holds
abs ((f . x1) - (f . x2)) < r
by A2, Th1;
take s =
s;
( 0 < s & ( for x1, x2 being Real st x1 in dom ((p (#) f) | X) & x2 in dom ((p (#) f) | X) & abs (x1 - x2) < s holds
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < r ) )thus
0 < s
by A5;
for x1, x2 being Real st x1 in dom ((p (#) f) | X) & x2 in dom ((p (#) f) | X) & abs (x1 - x2) < s holds
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < rlet x1,
x2 be
Real;
( x1 in dom ((p (#) f) | X) & x2 in dom ((p (#) f) | X) & abs (x1 - x2) < s implies abs (((p (#) f) . x1) - ((p (#) f) . x2)) < r )assume that A6:
x1 in dom ((p (#) f) | X)
and A7:
x2 in dom ((p (#) f) | X)
and
abs (x1 - x2) < s
;
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < rA8:
x2 in X
by A7, RELAT_1:57;
x1 in X
by A6, RELAT_1:57;
then abs (((p (#) f) . x1) - ((p (#) f) . x2)) =
abs ((p * (f . x1)) - ((p (#) f) . x2))
by A1, VALUED_1:def 5
.=
abs (0 - (p * (f . x2)))
by A1, A3, A8, VALUED_1:def 5
.=
0
by A3, ABSVALUE:2
;
hence
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < r
by A4;
verum end; hence
(p (#) f) | X is
uniformly_continuous
by Th1;
verum end; suppose A9:
p <> 0
;
(p (#) f) | X is uniformly_continuous then A10:
0 < abs p
by COMPLEX1:47;
A11:
0 <> abs p
by A9, COMPLEX1:47;
now let r be
Real;
( 0 < r implies ex s being Real st
( 0 < s & ( for x1, x2 being Real st x1 in dom ((p (#) f) | X) & x2 in dom ((p (#) f) | X) & abs (x1 - x2) < s holds
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < r ) ) )assume
0 < r
;
ex s being Real st
( 0 < s & ( for x1, x2 being Real st x1 in dom ((p (#) f) | X) & x2 in dom ((p (#) f) | X) & abs (x1 - x2) < s holds
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < r ) )then
0 < r / (abs p)
by A10, XREAL_1:139;
then consider s being
Real such that A12:
0 < s
and A13:
for
x1,
x2 being
Real st
x1 in dom (f | X) &
x2 in dom (f | X) &
abs (x1 - x2) < s holds
abs ((f . x1) - (f . x2)) < r / (abs p)
by A2, Th1;
take s =
s;
( 0 < s & ( for x1, x2 being Real st x1 in dom ((p (#) f) | X) & x2 in dom ((p (#) f) | X) & abs (x1 - x2) < s holds
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < r ) )thus
0 < s
by A12;
for x1, x2 being Real st x1 in dom ((p (#) f) | X) & x2 in dom ((p (#) f) | X) & abs (x1 - x2) < s holds
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < rlet x1,
x2 be
Real;
( x1 in dom ((p (#) f) | X) & x2 in dom ((p (#) f) | X) & abs (x1 - x2) < s implies abs (((p (#) f) . x1) - ((p (#) f) . x2)) < r )assume that A14:
x1 in dom ((p (#) f) | X)
and A15:
x2 in dom ((p (#) f) | X)
and A16:
abs (x1 - x2) < s
;
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < rA17:
x2 in X
by A15, RELAT_1:57;
A18:
x1 in X
by A14, RELAT_1:57;
then A19:
abs (((p (#) f) . x1) - ((p (#) f) . x2)) =
abs ((p * (f . x1)) - ((p (#) f) . x2))
by A1, VALUED_1:def 5
.=
abs ((p * (f . x1)) - (p * (f . x2)))
by A1, A17, VALUED_1:def 5
.=
abs (p * ((f . x1) - (f . x2)))
.=
(abs p) * (abs ((f . x1) - (f . x2)))
by COMPLEX1:65
;
x2 in dom (p (#) f)
by A15, RELAT_1:57;
then
x2 in dom f
by VALUED_1:def 5;
then A20:
x2 in dom (f | X)
by A17, RELAT_1:57;
x1 in dom (p (#) f)
by A14, RELAT_1:57;
then
x1 in dom f
by VALUED_1:def 5;
then
x1 in dom (f | X)
by A18, RELAT_1:57;
then
(abs p) * (abs ((f . x1) - (f . x2))) < (r / (abs p)) * (abs p)
by A10, A13, A16, A20, XREAL_1:68;
hence
abs (((p (#) f) . x1) - ((p (#) f) . x2)) < r
by A11, A19, XCMPLX_1:87;
verum end; hence
(p (#) f) | X is
uniformly_continuous
by Th1;
verum end; end;