Assignment:
Let m be a sigma-algebra, M_1 and M_2 are measures on m.
a). Is M = M_1 + M_2 a measure?
b). Is M = M_1 - M_2 a measure?
c). Is M = M_1M_2 a measure?
Either prove or disprove by providing a counter example.
Provide complete and step by step solution for the question and show calculations and use formulas.