Our paper, Sequential Transport for Causal Mediation Analysis, with Agathe Fernandes-Machado, Iryna Voitsitska and Ewen Gallic, is now available on https://arxiv.org/abs/2603.15182 We propose sequential transport (ST), a distributional framework for mediation analysis that combines optimal transport (OT) with a mediator directed acyclic graph (DAG). Instead of relying on cross-world counterfactual assumptions, ST constructs unit-level mediator counterfactuals by minimally transporting each mediator, either marginally or conditionally, toward its distribution under an alternative treatment …