A key observation underlying the development of UEM is that hard EM (or CoDL) finds a distribution with zero entropy while EM (or PR) finds a distribution with the same entropy as P θ (or close to it).
we modify the objective of the E-step of EM 3as where KL(q, p; γ) is a modified KL divergence: In other words, UEM projects P θ (h|x) on the space of feasible distributions Q w.r.t.