let n be non zero Nat; for f being PartFunc of (CarProduct ((Seg n) --> REAL)),ExtREAL
for g being PartFunc of (REAL n),ExtREAL
for A being Element of Prod_Field (L-Field n) st g = f * ((CarProd ((Seg n) --> REAL)) ") & A = dom f & f is A -measurable holds
Integral ((XL-Meas n),g) = Integral ((Prod_Measure (L-Meas n)),f)
let f be PartFunc of (CarProduct ((Seg n) --> REAL)),ExtREAL; for g being PartFunc of (REAL n),ExtREAL
for A being Element of Prod_Field (L-Field n) st g = f * ((CarProd ((Seg n) --> REAL)) ") & A = dom f & f is A -measurable holds
Integral ((XL-Meas n),g) = Integral ((Prod_Measure (L-Meas n)),f)
let g be PartFunc of (REAL n),ExtREAL; for A being Element of Prod_Field (L-Field n) st g = f * ((CarProd ((Seg n) --> REAL)) ") & A = dom f & f is A -measurable holds
Integral ((XL-Meas n),g) = Integral ((Prod_Measure (L-Meas n)),f)
let A be Element of Prod_Field (L-Field n); ( g = f * ((CarProd ((Seg n) --> REAL)) ") & A = dom f & f is A -measurable implies Integral ((XL-Meas n),g) = Integral ((Prod_Measure (L-Meas n)),f) )
assume that
A1:
g = f * ((CarProd ((Seg n) --> REAL)) ")
and
A2:
A = dom f
and
A3:
f is A -measurable
; Integral ((XL-Meas n),g) = Integral ((Prod_Measure (L-Meas n)),f)
product ((Seg n) --> REAL) = REAL n
by SRINGS_5:8;
hence
Integral ((XL-Meas n),g) = Integral ((Prod_Measure (L-Meas n)),f)
by A1, A2, A3, Th12, Th32; verum