let a be Complex; :: thesis: for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for f being PartFunc of X,COMPLEX st f in L1_CFunctions M holds
a (#) f in L1_CFunctions M

let X be non empty set ; :: thesis: for S being SigmaField of X
for M being sigma_Measure of S
for f being PartFunc of X,COMPLEX st f in L1_CFunctions M holds
a (#) f in L1_CFunctions M

let S be SigmaField of X; :: thesis: for M being sigma_Measure of S
for f being PartFunc of X,COMPLEX st f in L1_CFunctions M holds
a (#) f in L1_CFunctions M

let M be sigma_Measure of S; :: thesis: for f being PartFunc of X,COMPLEX st f in L1_CFunctions M holds
a (#) f in L1_CFunctions M

let f be PartFunc of X,COMPLEX; :: thesis: ( f in L1_CFunctions M implies a (#) f in L1_CFunctions M )
set W = L1_CFunctions M;
assume f in L1_CFunctions M ; :: thesis: a (#) f in L1_CFunctions M
then ex f1 being PartFunc of X,COMPLEX st
( f1 = f & ex ND being Element of S st
( M . ND = 0 & dom f1 = ND ` & f1 is_integrable_on M ) ) ;
then consider ND being Element of S such that
A1: M . ND = 0 and
A2: ( dom f = ND ` & f is_integrable_on M ) ;
( dom (a (#) f) = ND ` & a (#) f is_integrable_on M ) by A2, MESFUN6C:40, VALUED_1:def 5;
hence a (#) f in L1_CFunctions M by A1; :: thesis: verum