let X be non empty set ; for S being SigmaField of X
for M being sigma_Measure of S
for f being PartFunc of X,REAL
for A being Element of S st ex E being Element of S st
( E = dom f & f is_measurable_on E ) & f is nonnegative holds
0 <= Integral M,(f | A)
let S be SigmaField of X; for M being sigma_Measure of S
for f being PartFunc of X,REAL
for A being Element of S st ex E being Element of S st
( E = dom f & f is_measurable_on E ) & f is nonnegative holds
0 <= Integral M,(f | A)
let M be sigma_Measure of S; for f being PartFunc of X,REAL
for A being Element of S st ex E being Element of S st
( E = dom f & f is_measurable_on E ) & f is nonnegative holds
0 <= Integral M,(f | A)
let f be PartFunc of X,REAL ; for A being Element of S st ex E being Element of S st
( E = dom f & f is_measurable_on E ) & f is nonnegative holds
0 <= Integral M,(f | A)
let A be Element of S; ( ex E being Element of S st
( E = dom f & f is_measurable_on E ) & f is nonnegative implies 0 <= Integral M,(f | A) )
assume that
A1:
ex E being Element of S st
( E = dom f & f is_measurable_on E )
and
A2:
f is nonnegative
; 0 <= Integral M,(f | A)
consider E being Element of S such that
A3:
E = dom f
and
A4:
f is_measurable_on E
by A1;
R_EAL f is_measurable_on E
by A4, Def6;
hence
0 <= Integral M,(f | A)
by A2, A3, MESFUNC5:98; verum