Markov Mixed Membership Models

Abstract

We present a Markov mixed membership model (Markov M3) for grouped data that learns a fully connected graph structure among mixing components. A key feature of Markov M3 is that it interprets the mixed membership assignment as a Markov random walk over this graph of nodes. This is in contrast to tree-structured models in which the assignment is done according to a tree structure on the mixing components. The Markov structure results in a simple parametric model that can learn a complex dependency structure between nodes, while still maintaining full conjugacy for closed-form stochastic variational inference. Empirical results demonstrate that Markov M3 performs well compared with tree structured topic models, and can learn meaningful dependency structure between topics.