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A Stronger Calculus of Intervention for Max-Linear Bayesian Networks
Proceedings of the 42nd Conference on Uncertainty in Artificial Intelligence, PMLR 337:6342-6365, 2026.
Abstract
Max-linear {Bayesian} networks (MLBNs) are a novel class of directed acyclic graphical models which are of interest to statistics and data science due to their relevance to causality and probabilistic inference, particularly of extreme events. Interestingly, MLBNs encode strictly more conditional independence than general structural causal models. Because of this, MLBNs are {Markov} to a strengthening of the $d$-separation criterion called $\ast$-separation. As many tools for causal inference (most notably, Judea {Pearl}’s $do$-calculus) are based on $d$-separation, we address the natural question of whether assuming Markovianity to $\ast$-separation can lead to additional causal effect identifiability under intervention. We answer this question in the affirmative and develop a stronger version of the $do$-calculus rules for models which are {Markov} to $\ast$-separation. However, we note that restrictions inherent to the max-linear setting (in particular, that they give rise to non strictly positive joint probability distributions) mean that our calculus is only applicable to specific kinds of policy intervention.