Los Angeles Math Circle

5/24: Group A: Expected Value (part II)
Group B: Convolution, Mobius inversion, and why you might find them useful.

Group B: Please go over the proof of the fact that Euler's function phi(n) is multiplicative in preparation for the meeting. We will discover some properties of convolution; prove Mobius inversion formula (via convolution), and use all of these in problem solving.