theorem Th65: :: MEASUR11:69
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for E being Element of sigma (measurable_rectangles (S1,S2))
for A being Element of S1
for B being Element of S2
for x being Element of X1
for y being Element of X2 st E = [:A,B:] holds
( Integral (M2,(ProjMap1 ((chi (E,[:X1,X2:])),x))) = (M2 . (Measurable-X-section (E,x))) * ((chi (A,X1)) . x) & Integral (M1,(ProjMap2 ((chi (E,[:X1,X2:])),y))) = (M1 . (Measurable-Y-section (E,y))) * ((chi (B,X2)) . y) )