let X be non empty set ; for S being SigmaField of X
for M being sigma_Measure of S
for A being Element of S
for f, g being PartFunc of X,ExtREAL st A c= dom f & f is_measurable_on A & g is_measurable_on A & f is without-infty & g is without-infty holds
(max+ (f + g)) + (max- f) is_measurable_on A
let S be SigmaField of X; for M being sigma_Measure of S
for A being Element of S
for f, g being PartFunc of X,ExtREAL st A c= dom f & f is_measurable_on A & g is_measurable_on A & f is without-infty & g is without-infty holds
(max+ (f + g)) + (max- f) is_measurable_on A
let M be sigma_Measure of S; for A being Element of S
for f, g being PartFunc of X,ExtREAL st A c= dom f & f is_measurable_on A & g is_measurable_on A & f is without-infty & g is without-infty holds
(max+ (f + g)) + (max- f) is_measurable_on A
let A be Element of S; for f, g being PartFunc of X,ExtREAL st A c= dom f & f is_measurable_on A & g is_measurable_on A & f is without-infty & g is without-infty holds
(max+ (f + g)) + (max- f) is_measurable_on A
let f, g be PartFunc of X,ExtREAL; ( A c= dom f & f is_measurable_on A & g is_measurable_on A & f is without-infty & g is without-infty implies (max+ (f + g)) + (max- f) is_measurable_on A )
assume that
A1:
A c= dom f
and
A2:
f is_measurable_on A
and
A3:
g is_measurable_on A
and
A4:
f is without-infty
and
A5:
g is without-infty
; (max+ (f + g)) + (max- f) is_measurable_on A
f + g is_measurable_on A
by A2, A3, A4, A5, Th37;
then A6:
max+ (f + g) is_measurable_on A
by MESFUNC2:27;
A7:
max- f is nonnegative
by Lm1;
A8:
max+ (f + g) is nonnegative
by Lm1;
max- f is_measurable_on A
by A1, A2, MESFUNC2:28;
hence
(max+ (f + g)) + (max- f) is_measurable_on A
by A6, A8, A7, Th37; verum