let X be non empty set ; for S being SigmaField of X
for M being sigma_Measure of S
for f, g being PartFunc of X,COMPLEX st f is_integrable_on M & g is_integrable_on M holds
f + g is_integrable_on M
let S be SigmaField of X; for M being sigma_Measure of S
for f, g being PartFunc of X,COMPLEX st f is_integrable_on M & g is_integrable_on M holds
f + g is_integrable_on M
let M be sigma_Measure of S; for f, g being PartFunc of X,COMPLEX st f is_integrable_on M & g is_integrable_on M holds
f + g is_integrable_on M
let f, g be PartFunc of X,COMPLEX; ( f is_integrable_on M & g is_integrable_on M implies f + g is_integrable_on M )
assume that
A1:
f is_integrable_on M
and
A2:
g is_integrable_on M
; f + g is_integrable_on M
A3:
Im g is_integrable_on M
by A2;
Im f is_integrable_on M
by A1;
then
(Im f) + (Im g) is_integrable_on M
by A3, MESFUNC6:100;
then A4:
Im (f + g) is_integrable_on M
by Th5;
A5:
Re g is_integrable_on M
by A2;
Re f is_integrable_on M
by A1;
then
(Re f) + (Re g) is_integrable_on M
by A5, MESFUNC6:100;
then
Re (f + g) is_integrable_on M
by Th5;
hence
f + g is_integrable_on M
by A4; verum