Research
I use algebra, geometry and combinatorics to understand statistical models: what they look like, how to represent them, and when their estimators have closed-form solutions.
Staged trees and context-specific models
Staged trees represent statistical models in which some independences hold only in certain contexts. I study their defining equations, when two trees describe the same model, and how to learn them from observational and interventional data.
Graphical and causal models
Graphical models encode dependence between random variables with a graph. I study their algebraic structure, from discrete models with interventions to Gaussian polytrees, and recently to quantum many-body systems.
Maximum likelihood and algebraic optimization
Which discrete statistical models have a maximum likelihood estimator given by a rational formula? This question connects statistics with toric geometry and polytopes. I also study related optimization problems, such as finding the closest point to a model in polyhedral norms.
Geometric modeling and implicitization
Curves and surfaces in computer-aided design are given by parametrizations. Finding their implicit equations uses syzygies and free resolutions from commutative algebra.
Software
staged-tree
A formalization of staged trees in the Lean 4 proof assistant.
Rational MLE
Code accompanying Discrete statistical models with rational MLE.