Lebesgue Outer Measure is not Finitely Additive.

594 Views Asked by At

We know that Lebesgue Outer Measure is countably sub-additive. It is not even finitely additive. I am trying to find two sets of real numbers which are disjoint and yet $\mu ^*(A\cup B) = \mu^*(A) +\mu^*(B)$ doesn't hold.