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,REAL
for A, B being Element of S st f is_integrable_on M & A misses B holds
Integral M,(f | (A \/ B)) = (Integral M,(f | A)) + (Integral M,(f | B))

let S be SigmaField of X; :: thesis: for M being sigma_Measure of S
for f being PartFunc of X,REAL
for A, B being Element of S st f is_integrable_on M & A misses B holds
Integral M,(f | (A \/ B)) = (Integral M,(f | A)) + (Integral M,(f | B))

let M be sigma_Measure of S; :: thesis: for f being PartFunc of X,REAL
for A, B being Element of S st f is_integrable_on M & A misses B holds
Integral M,(f | (A \/ B)) = (Integral M,(f | A)) + (Integral M,(f | B))

let f be PartFunc of X,REAL ; :: thesis: for A, B being Element of S st f is_integrable_on M & A misses B holds
Integral M,(f | (A \/ B)) = (Integral M,(f | A)) + (Integral M,(f | B))

let A, B be Element of S; :: thesis: ( f is_integrable_on M & A misses B implies Integral M,(f | (A \/ B)) = (Integral M,(f | A)) + (Integral M,(f | B)) )
assume A1: ( f is_integrable_on M & A misses B ) ; :: thesis: Integral M,(f | (A \/ B)) = (Integral M,(f | A)) + (Integral M,(f | B))
then R_EAL f is_integrable_on M by Def9;
hence Integral M,(f | (A \/ B)) = (Integral M,(f | A)) + (Integral M,(f | B)) by A1, MESFUNC5:104; :: thesis: verum