Search Results for author: Facundo Mémoli

Found 18 papers, 5 papers with code

Geometry and Stability of Supervised Learning Problems

no code implementations4 Mar 2024 Facundo Mémoli, Brantley Vose, Robert C. Williamson

We introduce a notion of distance between supervised learning problems, which we call the Risk distance.

The Weisfeiler-Lehman Distance: Reinterpretation and Connection with GNNs

no code implementations1 Feb 2023 Samantha Chen, Sunhyuk Lim, Facundo Mémoli, Zhengchao Wan, Yusu Wang

This new interpretation connects the WL distance to the literature on distances for stochastic processes, which also makes the interpretation of the distance more accessible and intuitive.

Weisfeiler-Lehman meets Gromov-Wasserstein

no code implementations5 Feb 2022 Samantha Chen, Sunhyuk Lim, Facundo Mémoli, Zhengchao Wan, Yusu Wang

The WL distance is polynomial time computable and is also compatible with the WL test in the sense that the former is positive if and only if the WL test can distinguish the two involved graphs.

Isomorphism Testing

Robust Hierarchical Clustering for Directed Networks: An Axiomatic Approach

no code implementations16 Aug 2021 Gunnar Carlsson, Facundo Mémoli, Santiago Segarra

We begin by introducing three practical properties associated with the notion of robustness in hierarchical clustering: linear scale preservation, stability, and excisiveness.

Clustering

The ultrametric Gromov-Wasserstein distance

1 code implementation14 Jan 2021 Facundo Mémoli, Axel Munk, Zhengchao Wan, Christoph Weitkamp

In this paper, we investigate compact ultrametric measure spaces which form a subset $\mathcal{U}^w$ of the collection of all metric measure spaces $\mathcal{M}^w$.

Metric Geometry Populations and Evolution

The Gaussian Transform

no code implementations21 Jun 2020 Kun Jin, Facundo Mémoli, Zhengchao Wan

Our contribution is twofold: (1) theoretically, we establish firstly that GT is stable under perturbations and secondly that in the continuous case, each point possesses an asymptotically ellipsoidal neighborhood with respect to the GT distance; (2) computationally, we accelerate GT both by identifying a strategy for reducing the number of matrix square root computations inherent to the $\ell^2$-Wasserstein distance between Gaussian measures, and by avoiding redundant computations of GT distances between points via enhanced neighborhood mechanisms.

Denoising

Motivic clustering schemes for directed graphs

no code implementations1 Jan 2020 Facundo Mémoli, Guilherme Vituri F. Pinto

Motivated by the concept of network motifs we construct certain clustering methods (functors) which are parametrized by a given collection of motifs (or representers).

Clustering

Persistent Homotopy Groups of Metric Spaces

1 code implementation28 Dec 2019 Facundo Mémoli, Ling Zhou

We pay particular attention to the case of fundamental groups, for which we obtain a more precise description.

Algebraic Topology Computational Geometry 53C23, 51F99, 55N35

On $p$-metric spaces and the $p$-Gromov-Hausdorff distance

1 code implementation2 Dec 2019 Facundo Mémoli, Zane Smith, Zhengchao Wan

For each given $p\in[1,\infty]$ we investigate certain sub-family $\mathcal{M}_p$ of the collection of all compact metric spaces $\mathcal{M}$ which are characterized by the satisfaction of a strengthened form of the triangle inequality which encompasses, for example, the strong triangle inequality satisfied by ultrametric spaces.

Metric Geometry

The Wasserstein transform

no code implementations17 Oct 2018 Facundo Mémoli, Zane Smith, Zhengchao Wan

We introduce the Wasserstein transform, a method for enhancing and denoising datasets defined on general metric spaces.

Denoising

The Gromov-Wasserstein distance between networks and stable network invariants

1 code implementation13 Aug 2018 Samir Chowdhury, Facundo Mémoli

We define a metric---the Network Gromov-Wasserstein distance---on weighted, directed networks that is sensitive to the presence of outliers.

Discrete Mathematics Metric Geometry

Hierarchical Clustering of Asymmetric Networks

no code implementations21 Jul 2016 Gunnar Carlsson, Facundo Mémoli, Alejandro Ribeiro, Santiago Segarra

This paper considers networks where relationships between nodes are represented by directed dissimilarities.

Clustering

Excisive Hierarchical Clustering Methods for Network Data

no code implementations21 Jul 2016 Gunnar Carlsson, Facundo Mémoli, Alejandro Ribeiro, Santiago Segarra

We introduce two practical properties of hierarchical clustering methods for (possibly asymmetric) network data: excisiveness and linear scale preservation.

Clustering

Admissible Hierarchical Clustering Methods and Algorithms for Asymmetric Networks

no code implementations21 Jul 2016 Gunnar Carlsson, Facundo Mémoli, Alejandro Ribeiro, Santiago Segarra

This paper characterizes hierarchical clustering methods that abide by two previously introduced axioms -- thus, denominated admissible methods -- and proposes tractable algorithms for their implementation.

Clustering

The Shape of Data and Probability Measures

1 code implementation15 Sep 2015 Diego Hernán Díaz Martínez, Facundo Mémoli, Washington Mio

We introduce the notion of multiscale covariance tensor fields (CTF) associated with Euclidean random variables as a gateway to the shape of their distributions.

Clustering

Hierarchical Quasi-Clustering Methods for Asymmetric Networks

no code implementations17 Apr 2014 Gunnar Carlsson, Facundo Mémoli, Alejandro Ribeiro, Santiago Segarra

This paper introduces hierarchical quasi-clustering methods, a generalization of hierarchical clustering for asymmetric networks where the output structure preserves the asymmetry of the input data.

Clustering

Axiomatic Construction of Hierarchical Clustering in Asymmetric Networks

no code implementations31 Jan 2013 Gunnar Carlsson, Facundo Mémoli, Alejandro Ribeiro, Santiago Segarra

Our construction of hierarchical clustering methods is based on defining admissible methods to be those methods that abide by the axioms of value - nodes in a network with two nodes are clustered together at the maximum of the two dissimilarities between them - and transformation - when dissimilarities are reduced, the network may become more clustered but not less.

Clustering

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