Adapting a definition given by Bjerkevik and Lesnick [9] for multiparameter persistence modules, we introduce an p -type extension of the interleaving distance on merge trees. We show that our distance is a metric, and that it upper-bounds the p-Wasserstein distance between the associated barcodes. For each p ∈ [1, ∞], we prove that this distance is stable with respect to cellular sublevel filtrations and that it is the universal (i.e., largest) distance satisfying this stability property. In the p = ∞ case, this gives a novel proof of universality for the interleaving distance on merge trees.
ACM Subject ClassificationMathematics of computing → Algebraic topology; Theory of computation → Unsupervised learning and clustering; Theory of computation → Computational geometry Keywords and phrases merge trees, hierarchical clustering, persistent homology, Wasserstein distances, interleavings Funding Justin Curry: Supported by NSF CCF-1850052 and NASA 80GRC020C0016Acknowledgements While Håvard Bjerkevik was not directly involved in this project, he has had a major influence on it, via his collaboration with ML on presentation distances for multiparameter persistence modules [9]. In particular, Håvard kindly agreed to share an early draft of [9] with our group in July 2020, which inspired many of the ideas in our paper.