This was part of New Directions in Algebraic Statistics 

One-dimensional Models of ML Degree One: Algebraic Statistics Meets Cauchy-Riemann Geometry

Carlos Amendola, Technische Universität Berlin

Friday, July 25, 2025



Slides
Abstract: A prominent success story in algebraic statistics is the study of maximum likelihood (ML) estimation for statistical models as an algebraic optimization problem. The algebraic complexity of this problem is measured by a model invariant known as the ML degree. When the ML degree is one, the statistical model admits a rational maximum likelihood estimator as a function of the data. A classification of ML degree one discrete models which are themselves one-dimensional was started by Bik and Marigliano, where they conjectured the degree of any such model is bounded above by a linear function in the size of its support. We prove this conjecture, therefore showing that there are only finitely many fundamental such models for any given number of states. We show how the enumeration of fundamental models is closely related to counting classes of monomial maps between unit spheres, a topic extensively studied by Cauchy-Riemann geometry. In this way, we unveil a promising new direction for algebraic statistics. Based on joint work with Viet Duc Nguyen and Janike Oldekop.