Polynomial Semantics of Tractable Probabilistic Circuits

Oliver Broadrick, Honghua Zhang, Guy Van den Broeck

Keywords: Probabilistic Inference, Marginal Inference, Tractable Models, Probabilistic Circuits, Arithmetic Circuits, Expressive-Efficiency

Abstract: Probabilistic circuits compute multilinear polynomials that represent probability distributions. They are tractable models that support efficient marginal inference. However, various polynomial semantics have been considered in the literature (e.g., network polynomials, likelihood polynomials, generating functions, Fourier transforms, and characteristic polynomials). The relationships between these polynomial encodings of distributions is largely unknown. In this paper, we prove that for binary distributions, each of these probabilistic circuit models is equivalent in the sense that any circuit for one of them can be transformed into a circuit for any of the others with only a polynomial increase in size. They are therefore all tractable for marginal inference on the same class of distributions. Finally, we explore the natural extension of one such polynomial semantics, called probabilistic generating circuits, to categorical random variables, and establish that marginal inference becomes #P-hard.

List Of Authors: Broadrick, Oliver and Zhang, Honghua and Van den Broeck, Guy

Submission Number: 739