On the Mobius Function of a Finite Group

I will present the results of Hawkes, Isaacs, and Ozaydin from their paper “On the Mobius Function of a Finite Group.”  I will discuss some results in the literature prior to this paper and how the authors’ results generalize previous theorems.  I will end with a theorem of the authors relating the Mobius number of the subgroup lattice of a finite solvable group to the Mobius number of its conjugacy class subgroup poset.