theorem :: MESFUN17:50

for I, J, K being non empty closed_interval Subset of REAL
for f being PartFunc of [:[:RNS_Real,RNS_Real:],RNS_Real:],RNS_Real
for g being PartFunc of [:[:REAL,REAL:],REAL:],REAL
for E being Element of L-Field st [:[:I,J:],K:] = dom f & f is_continuous_on [:[:I,J:],K:] & f = g holds
Integral1 ((Prod_Measure (L-Meas,L-Meas)),|.(R_EAL g).|) is E -measurable