Mixtures of Discrete Decomposable Graphical Models

Abstract

We study mixtures of decomposable graphical models, focusing on their ideals and dimensions. For mixtures of clique stars, we characterize the ideals in terms of ideals of mixtures of independence models. We also give a recursive formula for their ML degrees. Finally, we prove that second secant varieties of all other decomposable graphical models have the expected dimension.

To appear in Algebraic Statistics