let E be RealNormSpace; for F being RealBanachSpace
for A being non empty Subset of E
for B being non empty Subset of F
for Fai being PartFunc of [:E,F:],F st B is closed & [:A,B:] c= dom Fai & ( for x being Point of E
for y being Point of F st x in A & y in B holds
Fai . (x,y) in B ) & ( for y being Point of F st y in B holds
for x0 being Point of E st x0 in A holds
for e being Real st 0 < e holds
ex d being Real st
( 0 < d & ( for x1 being Point of E st x1 in A & ||.(x1 - x0).|| < d holds
||.((Fai /. [x1,y]) - (Fai /. [x0,y])).|| < e ) ) ) & ex k being Real st
( 0 < k & k < 1 & ( for x being Point of E st x in A holds
for y1, y2 being Point of F st y1 in B & y2 in B holds
||.((Fai /. [x,y1]) - (Fai /. [x,y2])).|| <= k * ||.(y1 - y2).|| ) ) holds
( ex g being PartFunc of E,F st
( g is_continuous_on A & dom g = A & rng g c= B & ( for x being Point of E st x in A holds
Fai . (x,(g . x)) = g . x ) ) & ( for g1, g2 being PartFunc of E,F st dom g1 = A & rng g1 c= B & dom g2 = A & rng g2 c= B & ( for x being Point of E st x in A holds
Fai . (x,(g1 . x)) = g1 . x ) & ( for x being Point of E st x in A holds
Fai . (x,(g2 . x)) = g2 . x ) holds
g1 = g2 ) )
let F be RealBanachSpace; for A being non empty Subset of E
for B being non empty Subset of F
for Fai being PartFunc of [:E,F:],F st B is closed & [:A,B:] c= dom Fai & ( for x being Point of E
for y being Point of F st x in A & y in B holds
Fai . (x,y) in B ) & ( for y being Point of F st y in B holds
for x0 being Point of E st x0 in A holds
for e being Real st 0 < e holds
ex d being Real st
( 0 < d & ( for x1 being Point of E st x1 in A & ||.(x1 - x0).|| < d holds
||.((Fai /. [x1,y]) - (Fai /. [x0,y])).|| < e ) ) ) & ex k being Real st
( 0 < k & k < 1 & ( for x being Point of E st x in A holds
for y1, y2 being Point of F st y1 in B & y2 in B holds
||.((Fai /. [x,y1]) - (Fai /. [x,y2])).|| <= k * ||.(y1 - y2).|| ) ) holds
( ex g being PartFunc of E,F st
( g is_continuous_on A & dom g = A & rng g c= B & ( for x being Point of E st x in A holds
Fai . (x,(g . x)) = g . x ) ) & ( for g1, g2 being PartFunc of E,F st dom g1 = A & rng g1 c= B & dom g2 = A & rng g2 c= B & ( for x being Point of E st x in A holds
Fai . (x,(g1 . x)) = g1 . x ) & ( for x being Point of E st x in A holds
Fai . (x,(g2 . x)) = g2 . x ) holds
g1 = g2 ) )
let A be non empty Subset of E; for B being non empty Subset of F
for Fai being PartFunc of [:E,F:],F st B is closed & [:A,B:] c= dom Fai & ( for x being Point of E
for y being Point of F st x in A & y in B holds
Fai . (x,y) in B ) & ( for y being Point of F st y in B holds
for x0 being Point of E st x0 in A holds
for e being Real st 0 < e holds
ex d being Real st
( 0 < d & ( for x1 being Point of E st x1 in A & ||.(x1 - x0).|| < d holds
||.((Fai /. [x1,y]) - (Fai /. [x0,y])).|| < e ) ) ) & ex k being Real st
( 0 < k & k < 1 & ( for x being Point of E st x in A holds
for y1, y2 being Point of F st y1 in B & y2 in B holds
||.((Fai /. [x,y1]) - (Fai /. [x,y2])).|| <= k * ||.(y1 - y2).|| ) ) holds
( ex g being PartFunc of E,F st
( g is_continuous_on A & dom g = A & rng g c= B & ( for x being Point of E st x in A holds
Fai . (x,(g . x)) = g . x ) ) & ( for g1, g2 being PartFunc of E,F st dom g1 = A & rng g1 c= B & dom g2 = A & rng g2 c= B & ( for x being Point of E st x in A holds
Fai . (x,(g1 . x)) = g1 . x ) & ( for x being Point of E st x in A holds
Fai . (x,(g2 . x)) = g2 . x ) holds
g1 = g2 ) )
let B be non empty Subset of F; for Fai being PartFunc of [:E,F:],F st B is closed & [:A,B:] c= dom Fai & ( for x being Point of E
for y being Point of F st x in A & y in B holds
Fai . (x,y) in B ) & ( for y being Point of F st y in B holds
for x0 being Point of E st x0 in A holds
for e being Real st 0 < e holds
ex d being Real st
( 0 < d & ( for x1 being Point of E st x1 in A & ||.(x1 - x0).|| < d holds
||.((Fai /. [x1,y]) - (Fai /. [x0,y])).|| < e ) ) ) & ex k being Real st
( 0 < k & k < 1 & ( for x being Point of E st x in A holds
for y1, y2 being Point of F st y1 in B & y2 in B holds
||.((Fai /. [x,y1]) - (Fai /. [x,y2])).|| <= k * ||.(y1 - y2).|| ) ) holds
( ex g being PartFunc of E,F st
( g is_continuous_on A & dom g = A & rng g c= B & ( for x being Point of E st x in A holds
Fai . (x,(g . x)) = g . x ) ) & ( for g1, g2 being PartFunc of E,F st dom g1 = A & rng g1 c= B & dom g2 = A & rng g2 c= B & ( for x being Point of E st x in A holds
Fai . (x,(g1 . x)) = g1 . x ) & ( for x being Point of E st x in A holds
Fai . (x,(g2 . x)) = g2 . x ) holds
g1 = g2 ) )
let Fai be PartFunc of [:E,F:],F; ( B is closed & [:A,B:] c= dom Fai & ( for x being Point of E
for y being Point of F st x in A & y in B holds
Fai . (x,y) in B ) & ( for y being Point of F st y in B holds
for x0 being Point of E st x0 in A holds
for e being Real st 0 < e holds
ex d being Real st
( 0 < d & ( for x1 being Point of E st x1 in A & ||.(x1 - x0).|| < d holds
||.((Fai /. [x1,y]) - (Fai /. [x0,y])).|| < e ) ) ) & ex k being Real st
( 0 < k & k < 1 & ( for x being Point of E st x in A holds
for y1, y2 being Point of F st y1 in B & y2 in B holds
||.((Fai /. [x,y1]) - (Fai /. [x,y2])).|| <= k * ||.(y1 - y2).|| ) ) implies ( ex g being PartFunc of E,F st
( g is_continuous_on A & dom g = A & rng g c= B & ( for x being Point of E st x in A holds
Fai . (x,(g . x)) = g . x ) ) & ( for g1, g2 being PartFunc of E,F st dom g1 = A & rng g1 c= B & dom g2 = A & rng g2 c= B & ( for x being Point of E st x in A holds
Fai . (x,(g1 . x)) = g1 . x ) & ( for x being Point of E st x in A holds
Fai . (x,(g2 . x)) = g2 . x ) holds
g1 = g2 ) ) )
assume that
A1:
B is closed
and
A2:
[:A,B:] c= dom Fai
and
A3:
for x being Point of E
for y being Point of F st x in A & y in B holds
Fai . (x,y) in B
and
A4:
for y being Point of F st y in B holds
for x0 being Point of E st x0 in A holds
for e being Real st 0 < e holds
ex d being Real st
( 0 < d & ( for x1 being Point of E st x1 in A & ||.(x1 - x0).|| < d holds
||.((Fai /. [x1,y]) - (Fai /. [x0,y])).|| < e ) )
and
A5:
ex k being Real st
( 0 < k & k < 1 & ( for x being Point of E st x in A holds
for y1, y2 being Point of F st y1 in B & y2 in B holds
||.((Fai /. [x,y1]) - (Fai /. [x,y2])).|| <= k * ||.(y1 - y2).|| ) )
; ( ex g being PartFunc of E,F st
( g is_continuous_on A & dom g = A & rng g c= B & ( for x being Point of E st x in A holds
Fai . (x,(g . x)) = g . x ) ) & ( for g1, g2 being PartFunc of E,F st dom g1 = A & rng g1 c= B & dom g2 = A & rng g2 c= B & ( for x being Point of E st x in A holds
Fai . (x,(g1 . x)) = g1 . x ) & ( for x being Point of E st x in A holds
Fai . (x,(g2 . x)) = g2 . x ) holds
g1 = g2 ) )
thus
ex g being PartFunc of E,F st
( g is_continuous_on A & dom g = A & rng g c= B & ( for x being Point of E st x in A holds
Fai . (x,(g . x)) = g . x ) )
for g1, g2 being PartFunc of E,F st dom g1 = A & rng g1 c= B & dom g2 = A & rng g2 c= B & ( for x being Point of E st x in A holds
Fai . (x,(g1 . x)) = g1 . x ) & ( for x being Point of E st x in A holds
Fai . (x,(g2 . x)) = g2 . x ) holds
g1 = g2proof
defpred S1[
object ,
object ]
means ( $2
in B &
Fai . ($1,$2)
= $2 );
A6:
for
x,
y1,
y2 being
object st
x in A &
S1[
x,
y1] &
S1[
x,
y2] holds
y1 = y2
by A1, A2, A3, A4, A5, FIXPOINT2;
A7:
for
x being
object st
x in A holds
ex
y being
object st
S1[
x,
y]
proof
let x be
object ;
( x in A implies ex y being object st S1[x,y] )
assume A8:
x in A
;
ex y being object st S1[x,y]
then reconsider x0 =
x as
Point of
E ;
consider y being
Point of
F such that A9:
(
y in B &
Fai . (
x0,
y)
= y )
by A1, A2, A3, A4, A5, A8, FIXPOINT2;
take
y
;
S1[x,y]
thus
S1[
x,
y]
by A9;
verum
end;
consider g being
Function such that A10:
(
dom g = A & ( for
x being
object st
x in A holds
S1[
x,
g . x] ) )
from FUNCT_1:sch 2(A6, A7);
A11:
rng g c= B
then
rng g c= the
carrier of
F
by XBOOLE_1:1;
then
g in PFuncs ( the
carrier of
E, the
carrier of
F)
by A10, PARTFUN1:def 3;
then reconsider g =
g as
PartFunc of
E,
F by PARTFUN1:46;
take
g
;
( g is_continuous_on A & dom g = A & rng g c= B & ( for x being Point of E st x in A holds
Fai . (x,(g . x)) = g . x ) )
for
z0 being
Point of
E for
r being
Real st
z0 in A &
0 < r holds
ex
s being
Real st
(
0 < s & ( for
z1 being
Point of
E st
z1 in A &
||.(z1 - z0).|| < s holds
||.((g /. z1) - (g /. z0)).|| < r ) )
proof
let z0 be
Point of
E;
for r being Real st z0 in A & 0 < r holds
ex s being Real st
( 0 < s & ( for z1 being Point of E st z1 in A & ||.(z1 - z0).|| < s holds
||.((g /. z1) - (g /. z0)).|| < r ) )let r be
Real;
( z0 in A & 0 < r implies ex s being Real st
( 0 < s & ( for z1 being Point of E st z1 in A & ||.(z1 - z0).|| < s holds
||.((g /. z1) - (g /. z0)).|| < r ) ) )
assume A15:
(
z0 in A &
0 < r )
;
ex s being Real st
( 0 < s & ( for z1 being Point of E st z1 in A & ||.(z1 - z0).|| < s holds
||.((g /. z1) - (g /. z0)).|| < r ) )
then A16:
Fai . (
z0,
(g . z0))
= g . z0
by A10;
A17:
g . z0 in rng g
by A10, A15, FUNCT_1:3;
g . z0 = g /. z0
by A10, A15, PARTFUN1:def 6;
then consider s being
Real such that A18:
(
0 < s & ( for
x1 being
Point of
E for
y1 being
Point of
F st
x1 in A &
y1 in B &
Fai . (
x1,
y1)
= y1 &
||.(x1 - z0).|| < s holds
||.(y1 - (g /. z0)).|| < r ) )
by A1, A2, A3, A4, A5, A11, A15, A16, A17, FIXPOINT2;
take
s
;
( 0 < s & ( for z1 being Point of E st z1 in A & ||.(z1 - z0).|| < s holds
||.((g /. z1) - (g /. z0)).|| < r ) )
thus
0 < s
by A18;
for z1 being Point of E st z1 in A & ||.(z1 - z0).|| < s holds
||.((g /. z1) - (g /. z0)).|| < r
let z1 be
Point of
E;
( z1 in A & ||.(z1 - z0).|| < s implies ||.((g /. z1) - (g /. z0)).|| < r )
assume A19:
(
z1 in A &
||.(z1 - z0).|| < s )
;
||.((g /. z1) - (g /. z0)).|| < r
then A20:
Fai . (
z1,
(g . z1))
= g . z1
by A10;
A21:
g . z1 in B
by A10, A19;
g . z1 = g /. z1
by A10, A19, PARTFUN1:def 6;
hence
||.((g /. z1) - (g /. z0)).|| < r
by A18, A19, A20, A21;
verum
end;
hence
g is_continuous_on A
by A10, NFCONT_1:19;
( dom g = A & rng g c= B & ( for x being Point of E st x in A holds
Fai . (x,(g . x)) = g . x ) )
thus
(
dom g = A &
rng g c= B )
by A10, A11;
for x being Point of E st x in A holds
Fai . (x,(g . x)) = g . x
thus
for
x being
Point of
E st
x in A holds
Fai . (
x,
(g . x))
= g . x
by A10;
verum
end;
let g1, g2 be PartFunc of E,F; ( dom g1 = A & rng g1 c= B & dom g2 = A & rng g2 c= B & ( for x being Point of E st x in A holds
Fai . (x,(g1 . x)) = g1 . x ) & ( for x being Point of E st x in A holds
Fai . (x,(g2 . x)) = g2 . x ) implies g1 = g2 )
assume A22:
( dom g1 = A & rng g1 c= B & dom g2 = A & rng g2 c= B & ( for x being Point of E st x in A holds
Fai . (x,(g1 . x)) = g1 . x ) & ( for x being Point of E st x in A holds
Fai . (x,(g2 . x)) = g2 . x ) )
; g1 = g2
for x being object st x in dom g1 holds
g1 . x = g2 . x
proof
let x be
object ;
( x in dom g1 implies g1 . x = g2 . x )
assume A23:
x in dom g1
;
g1 . x = g2 . x
then reconsider y =
x as
Point of
E ;
A24:
g1 . y in rng g1
by A23, FUNCT_1:3;
then reconsider z1 =
g1 . y as
Point of
F ;
A25:
g2 . y in rng g2
by A22, A23, FUNCT_1:3;
then reconsider z2 =
g2 . y as
Point of
F ;
(
Fai . (
y,
z1)
= z1 &
Fai . (
y,
z2)
= z2 &
z1 in B &
z2 in B &
y in A )
by A22, A23, A24, A25;
hence
g1 . x = g2 . x
by A1, A2, A3, A4, A5, FIXPOINT2;
verum
end;
hence
g1 = g2
by A22, FUNCT_1:2; verum