let X be non empty set ; for S being SigmaField of X
for M being sigma_Measure of S
for E being Element of S
for F being Functional_Sequence of X,ExtREAL st E = dom (F . 0) & F . 0 is nonnegative & F is with_the_same_dom & ( for n being Nat holds F . n is_measurable_on E ) & ( for n, m being Nat st n <= m holds
for x being Element of X st x in E holds
(F . n) . x <= (F . m) . x ) & ( for x being Element of X st x in E holds
F # x is convergent ) holds
ex I being ExtREAL_sequence st
( ( for n being Nat holds I . n = Integral (M,(F . n)) ) & I is convergent & Integral (M,(lim F)) = lim I )
let S be SigmaField of X; for M being sigma_Measure of S
for E being Element of S
for F being Functional_Sequence of X,ExtREAL st E = dom (F . 0) & F . 0 is nonnegative & F is with_the_same_dom & ( for n being Nat holds F . n is_measurable_on E ) & ( for n, m being Nat st n <= m holds
for x being Element of X st x in E holds
(F . n) . x <= (F . m) . x ) & ( for x being Element of X st x in E holds
F # x is convergent ) holds
ex I being ExtREAL_sequence st
( ( for n being Nat holds I . n = Integral (M,(F . n)) ) & I is convergent & Integral (M,(lim F)) = lim I )
let M be sigma_Measure of S; for E being Element of S
for F being Functional_Sequence of X,ExtREAL st E = dom (F . 0) & F . 0 is nonnegative & F is with_the_same_dom & ( for n being Nat holds F . n is_measurable_on E ) & ( for n, m being Nat st n <= m holds
for x being Element of X st x in E holds
(F . n) . x <= (F . m) . x ) & ( for x being Element of X st x in E holds
F # x is convergent ) holds
ex I being ExtREAL_sequence st
( ( for n being Nat holds I . n = Integral (M,(F . n)) ) & I is convergent & Integral (M,(lim F)) = lim I )
let E be Element of S; for F being Functional_Sequence of X,ExtREAL st E = dom (F . 0) & F . 0 is nonnegative & F is with_the_same_dom & ( for n being Nat holds F . n is_measurable_on E ) & ( for n, m being Nat st n <= m holds
for x being Element of X st x in E holds
(F . n) . x <= (F . m) . x ) & ( for x being Element of X st x in E holds
F # x is convergent ) holds
ex I being ExtREAL_sequence st
( ( for n being Nat holds I . n = Integral (M,(F . n)) ) & I is convergent & Integral (M,(lim F)) = lim I )
let F be Functional_Sequence of X,ExtREAL; ( E = dom (F . 0) & F . 0 is nonnegative & F is with_the_same_dom & ( for n being Nat holds F . n is_measurable_on E ) & ( for n, m being Nat st n <= m holds
for x being Element of X st x in E holds
(F . n) . x <= (F . m) . x ) & ( for x being Element of X st x in E holds
F # x is convergent ) implies ex I being ExtREAL_sequence st
( ( for n being Nat holds I . n = Integral (M,(F . n)) ) & I is convergent & Integral (M,(lim F)) = lim I ) )
assume that
A1:
E = dom (F . 0)
and
A2:
F . 0 is nonnegative
and
A3:
F is with_the_same_dom
and
A4:
for n being Nat holds F . n is_measurable_on E
and
A5:
for n, m being Nat st n <= m holds
for x being Element of X st x in E holds
(F . n) . x <= (F . m) . x
and
A6:
for x being Element of X st x in E holds
F # x is convergent
; ex I being ExtREAL_sequence st
( ( for n being Nat holds I . n = Integral (M,(F . n)) ) & I is convergent & Integral (M,(lim F)) = lim I )
A7:
lim F is_measurable_on E
by A1, A3, A4, A6, MESFUNC8:25;
A8:
for n being Nat holds F . n is nonnegative
per cases
( ex n being Nat st M . (E /\ (eq_dom ((F . n),+infty))) <> 0 or for n being Nat holds M . (E /\ (eq_dom ((F . n),+infty))) = 0 )
;
suppose
ex
n being
Nat st
M . (E /\ (eq_dom ((F . n),+infty))) <> 0
;
ex I being ExtREAL_sequence st
( ( for n being Nat holds I . n = Integral (M,(F . n)) ) & I is convergent & Integral (M,(lim F)) = lim I )then consider N being
Nat such that A9:
M . (E /\ (eq_dom ((F . N),+infty))) <> 0
;
A10:
E = dom (F . N)
by A1, A3, MESFUNC8:def 2;
then reconsider EE =
E /\ (eq_dom ((F . N),+infty)) as
Element of
S by A4, MESFUNC1:33;
A11:
EE c= E
by XBOOLE_1:17;
then A12:
F . N is_measurable_on EE
by A4, MESFUNC1:30;
EE c= dom (F . N)
by A1, A3, A11, MESFUNC8:def 2;
then A13:
EE = dom ((F . N) | EE)
by RELAT_1:62;
then
EE = (dom (F . N)) /\ EE
by RELAT_1:61;
then A14:
(F . N) | EE is_measurable_on EE
by A12, MESFUNC5:42;
then A16:
EE c= eq_dom (
((F . N) | EE),
+infty)
by TARSKI:def 3;
for
x being
set st
x in eq_dom (
((F . N) | EE),
+infty) holds
x in EE
by A13, MESFUNC1:def 15;
then
eq_dom (
((F . N) | EE),
+infty)
c= EE
by TARSKI:def 3;
then
EE = eq_dom (
((F . N) | EE),
+infty)
by A16, XBOOLE_0:def 10;
then A17:
M . (EE /\ (eq_dom (((F . N) | EE),+infty))) <> 0
by A9;
F . N is_measurable_on E
by A4;
then A18:
Integral (
M,
((F . N) | EE))
<= Integral (
M,
((F . N) | E))
by A8, A10, A11, MESFUNC5:93;
reconsider N1 =
N as
Element of
NAT by ORDINAL1:def 12;
deffunc H1(
Element of
NAT )
-> Element of
ExtREAL =
Integral (
M,
(F . $1));
consider I being
Function of
NAT,
ExtREAL such that A19:
for
n being
Element of
NAT holds
I . n = H1(
n)
from FUNCT_2:sch 4();
reconsider I =
I as
ExtREAL_sequence ;
A20:
0 < M . (E /\ (eq_dom ((F . N),+infty)))
by A9, SUPINF_2:51;
A21:
for
n being
Nat holds
I . n = Integral (
M,
(F . n))
take
I
;
( ( for n being Nat holds I . n = Integral (M,(F . n)) ) & I is convergent & Integral (M,(lim F)) = lim I )A22:
dom (lim F) = dom (F . 0)
by MESFUNC8:def 9;
for
x being
set st
x in dom (lim F) holds
(lim F) . x >= 0
then A25:
lim F is
nonnegative
by SUPINF_2:52;
A26:
E = dom (lim F)
by A1, MESFUNC8:def 9;
A27:
EE c= E /\ (eq_dom ((lim F),+infty))
proof
let x be
set ;
TARSKI:def 3 ( not x in EE or x in E /\ (eq_dom ((lim F),+infty)) )
assume A28:
x in EE
;
x in E /\ (eq_dom ((lim F),+infty))
then reconsider x1 =
x as
Element of
X ;
x in eq_dom (
(F . N),
+infty)
by A28, XBOOLE_0:def 4;
then
(F . N) . x1 = +infty
by MESFUNC1:def 15;
then A29:
(F # x1) . N = +infty
by MESFUNC5:def 13;
A30:
x in E
by A28, XBOOLE_0:def 4;
for
n,
m being
Element of
NAT st
m <= n holds
(F # x1) . m <= (F # x1) . n
then A31:
F # x1 is
non-decreasing
by RINFSUP2:7;
then A32:
(F # x1) ^\ N1 is
non-decreasing
by RINFSUP2:26;
((F # x1) ^\ N1) . 0 = (F # x1) . (0 + N)
by NAT_1:def 3;
then
for
n being
Element of
NAT holds
+infty <= ((F # x1) ^\ N1) . n
by A29, A32, RINFSUP2:7;
then
(F # x1) ^\ N1 is
convergent_to_+infty
by RINFSUP2:32;
then A33:
lim ((F # x1) ^\ N1) = +infty
by Th7;
A34:
sup (F # x1) = sup ((F # x1) ^\ N1)
by A31, RINFSUP2:26;
lim (F # x1) = sup (F # x1)
by A31, RINFSUP2:37;
then
lim (F # x1) = +infty
by A32, A34, A33, RINFSUP2:37;
then
(lim F) . x1 = +infty
by A1, A22, A30, MESFUNC8:def 9;
then
x in eq_dom (
(lim F),
+infty)
by A26, A30, MESFUNC1:def 15;
hence
x in E /\ (eq_dom ((lim F),+infty))
by A30, XBOOLE_0:def 4;
verum
end; A35:
for
n,
m being
Element of
NAT st
m <= n holds
I . m <= I . n
proof
let n,
m be
Element of
NAT ;
( m <= n implies I . m <= I . n )
A36:
F . m is_measurable_on E
by A4;
assume
m <= n
;
I . m <= I . n
then A37:
for
x being
Element of
X st
x in E holds
(F . m) . x <= (F . n) . x
by A5;
A38:
E = dom (F . m)
by A1, A3, MESFUNC8:def 2;
A39:
E = dom (F . n)
by A1, A3, MESFUNC8:def 2;
F . n is_measurable_on E
by A4;
then
Integral (
M,
((F . m) | E))
<= Integral (
M,
((F . n) | E))
by A8, A38, A39, A36, A37, Th15;
then
Integral (
M,
(F . m))
<= Integral (
M,
((F . n) | E))
by A38, RELAT_1:68;
then
Integral (
M,
(F . m))
<= Integral (
M,
(F . n))
by A39, RELAT_1:68;
then
I . m <= Integral (
M,
(F . n))
by A19;
hence
I . m <= I . n
by A19;
verum
end; then A40:
I is
non-decreasing
by RINFSUP2:7;
then A41:
I ^\ N1 is
non-decreasing
by RINFSUP2:26;
F . N is
nonnegative
by A8;
then
Integral (
M,
((F . N) | EE))
= +infty
by A13, A14, A17, Th13, MESFUNC5:15;
then
+infty <= Integral (
M,
(F . N))
by A10, A18, RELAT_1:69;
then A42:
Integral (
M,
(F . N))
= +infty
by XXREAL_0:4;
for
k being
Element of
NAT holds
+infty <= (I ^\ N1) . k
then
I ^\ N1 is
convergent_to_+infty
by RINFSUP2:32;
then A43:
lim (I ^\ N1) = +infty
by Th7;
E /\ (eq_dom ((lim F),+infty)) is
Element of
S
by A7, A26, MESFUNC1:33;
then A44:
M . (E /\ (eq_dom ((lim F),+infty))) <> 0
by A27, A20, MEASURE1:31;
A45:
sup I = sup (I ^\ N1)
by A40, RINFSUP2:26;
lim I = sup I
by A40, RINFSUP2:37;
then
lim I = +infty
by A41, A45, A43, RINFSUP2:37;
hence
( ( for
n being
Nat holds
I . n = Integral (
M,
(F . n)) ) &
I is
convergent &
Integral (
M,
(lim F))
= lim I )
by A7, A21, A40, A26, A25, A44, Th13, RINFSUP2:37;
verum end; suppose A46:
for
n being
Nat holds
M . (E /\ (eq_dom ((F . n),+infty))) = 0
;
ex I being ExtREAL_sequence st
( ( for n being Nat holds I . n = Integral (M,(F . n)) ) & I is convergent & Integral (M,(lim F)) = lim I )defpred S1[
Element of
NAT ,
set ]
means $2
= E /\ (eq_dom ((F . $1),+infty));
A47:
for
n being
Element of
NAT ex
A being
Element of
S st
S1[
n,
A]
consider L being
Function of
NAT,
S such that A48:
for
n being
Element of
NAT holds
S1[
n,
L . n]
from FUNCT_2:sch 3(A47);
A49:
rng L c= S
by RELAT_1:def 19;
rng L is
N_Sub_set_fam of
X
by MEASURE1:23;
then reconsider E0 =
rng L as
N_Measure_fam of
S by A49, MEASURE2:def 1;
set E1 =
E \ (union E0);
deffunc H1(
Nat)
-> Element of
bool [:X,ExtREAL:] =
(F . $1) | (E \ (union E0));
consider H being
Functional_Sequence of
X,
ExtREAL such that A50:
for
n being
Nat holds
H . n = H1(
n)
from SEQFUNC:sch 1();
deffunc H2(
Element of
NAT )
-> Element of
ExtREAL =
Integral (
M,
((F . $1) | (E \ (union E0))));
consider I being
Function of
NAT,
ExtREAL such that A51:
for
n being
Element of
NAT holds
I . n = H2(
n)
from FUNCT_2:sch 4();
reconsider I =
I as
ExtREAL_sequence ;
A52:
E \ (union E0) c= E
by XBOOLE_1:36;
then A53:
for
n being
Nat holds
F . n is_measurable_on E \ (union E0)
by A4, MESFUNC1:30;
A54:
for
n being
Nat holds
(
dom (H . n) = E \ (union E0) &
H . n is
without-infty &
H . n is
without+infty )
proof
let n be
Nat;
( dom (H . n) = E \ (union E0) & H . n is without-infty & H . n is without+infty )
A55:
dom (H . n) = dom ((F . n) | (E \ (union E0)))
by A50;
E \ (union E0) c= dom (F . n)
by A1, A3, A52, MESFUNC8:def 2;
hence
dom (H . n) = E \ (union E0)
by A55, RELAT_1:62;
( H . n is without-infty & H . n is without+infty )
(F . n) | (E \ (union E0)) is
nonnegative
by A8, MESFUNC5:15;
then
H . n is
nonnegative
by A50;
hence
H . n is
without-infty
by MESFUNC5:12;
H . n is without+infty
for
x being
set st
x in dom (H . n) holds
(H . n) . x < +infty
proof
reconsider n1 =
n as
Element of
NAT by ORDINAL1:def 12;
let x be
set ;
( x in dom (H . n) implies (H . n) . x < +infty )
A56:
L . n = E /\ (eq_dom ((F . n1),+infty))
by A48;
dom L = NAT
by FUNCT_2:def 1;
then A57:
L . n in rng L
by A56, FUNCT_1:3;
assume
x in dom (H . n)
;
(H . n) . x < +infty
then A58:
x in dom ((F . n) | (E \ (union E0)))
by A50;
then A59:
x in E \ (union E0)
by RELAT_1:57;
A60:
x in dom (F . n)
by A58, RELAT_1:57;
assume A61:
(H . n) . x >= +infty
;
contradiction
(H . n) . x = ((F . n) | (E \ (union E0))) . x
by A50;
then
(H . n) . x = (F . n) . x
by A59, FUNCT_1:49;
then
(F . n) . x = +infty
by A61, XXREAL_0:4;
then
x in eq_dom (
(F . n),
+infty)
by A60, MESFUNC1:def 15;
then
x in L . n
by A52, A59, A56, XBOOLE_0:def 4;
then
x in union E0
by A57, TARSKI:def 4;
hence
contradiction
by A59, XBOOLE_0:def 5;
verum
end;
hence
H . n is
without+infty
by MESFUNC5:11;
verum
end;
for
n,
m being
Nat holds
dom (H . n) = dom (H . m)
then reconsider H =
H as
with_the_same_dom Functional_Sequence of
X,
ExtREAL by MESFUNC8:def 2;
defpred S2[
Element of
NAT ,
set ,
set ]
means $3
= (H . ($1 + 1)) - (H . $1);
A62:
for
n being
Element of
NAT for
x being
set ex
y being
set st
S2[
n,
x,
y]
;
consider G being
Function such that A63:
(
dom G = NAT &
G . 0 = H . 0 & ( for
n being
Element of
NAT holds
S2[
n,
G . n,
G . (n + 1)] ) )
from RECDEF_1:sch 1(A62);
A64:
for
n being
Nat holds
G . (n + 1) = (H . (n + 1)) - (H . n)
then
rng G c= PFuncs (
X,
ExtREAL)
by TARSKI:def 3;
then reconsider G =
G as
Functional_Sequence of
X,
ExtREAL by A63, FUNCT_2:def 1, RELSET_1:4;
A69:
for
n being
Nat holds
dom (G . n) = E \ (union E0)
A73:
for
n,
m being
Nat holds
dom (G . n) = dom (G . m)
A74:
for
n being
Nat holds
G . n is
nonnegative
proof
let n be
Nat;
G . n is nonnegative
A75:
(
n <> 0 implies
G . n is
nonnegative )
proof
assume
n <> 0
;
G . n is nonnegative
then consider k being
Nat such that A76:
n = k + 1
by NAT_1:6;
A77:
G . (k + 1) = (H . (k + 1)) - (H . k)
by A64;
for
x being
set st
x in dom (G . (k + 1)) holds
0 <= (G . (k + 1)) . x
proof
let x be
set ;
( x in dom (G . (k + 1)) implies 0 <= (G . (k + 1)) . x )
assume A78:
x in dom (G . (k + 1))
;
0 <= (G . (k + 1)) . x
A79:
dom (G . (k + 1)) = E \ (union E0)
by A69;
(H . k) . x = ((F . k) | (E \ (union E0))) . x
by A50;
then A80:
(H . k) . x = (F . k) . x
by A78, A79, FUNCT_1:49;
(H . (k + 1)) . x = ((F . (k + 1)) | (E \ (union E0))) . x
by A50;
then A81:
(H . (k + 1)) . x = (F . (k + 1)) . x
by A78, A79, FUNCT_1:49;
(F . k) . x <= (F . (k + 1)) . x
by A5, A52, A78, A79, NAT_1:11;
then
((H . (k + 1)) . x) - ((H . k) . x) >= 0
by A81, A80, XXREAL_3:40;
hence
0 <= (G . (k + 1)) . x
by A77, A78, MESFUNC1:def 4;
verum
end;
hence
G . n is
nonnegative
by A76, SUPINF_2:52;
verum
end;
(
n = 0 implies
G . n is
nonnegative )
hence
G . n is
nonnegative
by A75;
verum
end; A83:
for
n1 being
set st
n1 in NAT holds
H . n1 = (Partial_Sums G) . n1
then A95:
for
n being
Nat holds
(
H . n = (Partial_Sums G) . n &
lim H = lim (Partial_Sums G) )
by FUNCT_2:12;
reconsider G =
G as
with_the_same_dom Functional_Sequence of
X,
ExtREAL by A73, MESFUNC8:def 2;
reconsider G =
G as
with_the_same_dom additive Functional_Sequence of
X,
ExtREAL by A74, Th30;
A96:
for
k being
Nat holds
H . k is
real-valued
A98:
for
n being
Nat holds
G . n is_measurable_on E \ (union E0)
proof
let n be
Nat;
G . n is_measurable_on E \ (union E0)
(
n <> 0 implies
G . n is_measurable_on E \ (union E0) )
proof
assume
n <> 0
;
G . n is_measurable_on E \ (union E0)
then consider k being
Nat such that A99:
n = k + 1
by NAT_1:6;
A100:
E \ (union E0) = dom (H . k)
by A54;
A101:
G . (k + 1) = (H . (k + 1)) - (H . k)
by A64;
A102:
H . k is
real-valued
by A96;
A103:
H . k is_measurable_on E \ (union E0)
by A1, A3, A53, A50, Th20, XBOOLE_1:36;
A104:
H . (k + 1) is
real-valued
by A96;
H . (k + 1) is_measurable_on E \ (union E0)
by A1, A3, A53, A50, Th20, XBOOLE_1:36;
hence
G . n is_measurable_on E \ (union E0)
by A99, A103, A100, A104, A102, A101, MESFUNC2:11;
verum
end;
hence
G . n is_measurable_on E \ (union E0)
by A1, A3, A52, A53, A50, A63, Th20;
verum
end; A105:
E \ (union E0) = dom (G . 0)
by A54, A63;
for
x being
Element of
X st
x in E \ (union E0) holds
G # x is
summable
then consider J being
ExtREAL_sequence such that A107:
for
n being
Nat holds
J . n = Integral (
M,
((G . n) | (E \ (union E0))))
and
J is
summable
and A108:
Integral (
M,
((lim (Partial_Sums G)) | (E \ (union E0))))
= Sum J
by A74, A105, A98, Th51;
for
n being
set st
n in NAT holds
I . n = (Partial_Sums J) . n
then A110:
I = Partial_Sums J
by FUNCT_2:12;
dom (lim (Partial_Sums G)) = dom (H . 0)
by A95, MESFUNC8:def 9;
then
dom (lim (Partial_Sums G)) = E \ (union E0)
by A54;
then A111:
lim I = Integral (
M,
(lim H))
by A95, A108, A110, RELAT_1:68;
take
I
;
( ( for n being Nat holds I . n = Integral (M,(F . n)) ) & I is convergent & Integral (M,(lim F)) = lim I )A112:
for
x being
Element of
X st
x in E \ (union E0) holds
F # x is
convergent
A114:
for
n being
Element of
NAT st
0 <= n holds
(M * L) . n = 0
M * L is
nonnegative
by MEASURE2:1;
then
SUM (M * L) = (Ser (M * L)) . 0
by A114, SUPINF_2:48;
then
SUM (M * L) = (M * L) . 0
by SUPINF_2:44;
then
SUM (M * L) = 0
by A114;
then
M . (union E0) <= 0
by MEASURE2:11;
then A115:
M . (union E0) = 0
by SUPINF_2:51;
A116:
for
n being
Nat holds
I . n = Integral (
M,
(F . n))
for
n,
m being
Element of
NAT st
m <= n holds
I . m <= I . n
proof
let n,
m be
Element of
NAT ;
( m <= n implies I . m <= I . n )
A118:
F . m is
nonnegative
by A8;
A119:
dom (F . m) = E
by A1, A3, MESFUNC8:def 2;
assume
m <= n
;
I . m <= I . n
then A120:
for
x being
Element of
X st
x in dom (F . m) holds
(F . m) . x <= (F . n) . x
by A5, A119;
A121:
dom (F . n) = E
by A1, A3, MESFUNC8:def 2;
A122:
F . n is_measurable_on E
by A4;
A123:
F . n is
nonnegative
by A8;
F . m is_measurable_on E
by A4;
then
integral+ (
M,
(F . m))
<= integral+ (
M,
(F . n))
by A119, A121, A120, A118, A123, A122, MESFUNC5:85;
then
Integral (
M,
(F . m))
<= integral+ (
M,
(F . n))
by A4, A119, A118, MESFUNC5:88;
then
Integral (
M,
(F . m))
<= Integral (
M,
(F . n))
by A4, A121, A123, MESFUNC5:88;
then
I . m <= Integral (
M,
(F . n))
by A116;
hence
I . m <= I . n
by A116;
verum
end; then A124:
I is
non-decreasing
by RINFSUP2:7;
E = dom (lim F)
by A1, MESFUNC8:def 9;
then A125:
Integral (
M,
(lim F))
= Integral (
M,
((lim F) | (E \ (union E0))))
by A7, A115, MESFUNC5:95;
E \ (union E0) c= dom (F . 0)
by A1, XBOOLE_1:36;
hence
( ( for
n being
Nat holds
I . n = Integral (
M,
(F . n)) ) &
I is
convergent &
Integral (
M,
(lim F))
= lim I )
by A125, A50, A116, A124, A112, A111, Th19, RINFSUP2:37;
verum end; end;