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,ExtREAL st ex A being Element of S st
( A = dom f & f is A -measurable ) & f is nonnegative holds
0 <= Integral (M,f)
let S be SigmaField of X; for M being sigma_Measure of S
for f being PartFunc of X,ExtREAL st ex A being Element of S st
( A = dom f & f is A -measurable ) & f is nonnegative holds
0 <= Integral (M,f)
let M be sigma_Measure of S; for f being PartFunc of X,ExtREAL st ex A being Element of S st
( A = dom f & f is A -measurable ) & f is nonnegative holds
0 <= Integral (M,f)
let f be PartFunc of X,ExtREAL; ( ex A being Element of S st
( A = dom f & f is A -measurable ) & f is nonnegative implies 0 <= Integral (M,f) )
assume that
A1:
ex A being Element of S st
( A = dom f & f is A -measurable )
and
A2:
f is nonnegative
; 0 <= Integral (M,f)
0 <= integral+ (M,f)
by A1, A2, Th79;
hence
0 <= Integral (M,f)
by A1, A2, Th88; verum