theorem :: MESFUNC6:104
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,REAL
for r being Real
for B being Element of S st f is_integrable_on M holds
( f | B is_integrable_on M & Integral_on (M,B,(r (#) f)) = r * (Integral_on (M,B,f)) )