Séminaire Datashape
Manifold Learning between Mathematics and the Sciences
09
Oct. 2024
Intervenant : Marina Meila
Institution : University of Washington
Heure : 13h30 - 14h30
Lieu : 2L8

This talk will extend Manifold Learning in two directions.

First, we ask if it is possible, in the case of scientific data where quantitative prior knowledge is abundant, to explain a data manifold by new coordinates, chosen from a set of scientifically meaningful functions?

 Second, we ask how popular Manifold Learning tools and their applications can be recreated in the space of  vector fields and flows on a manifold. For this, we need to transport= advanced differential geometric and topological concepts into a data-driven framework.

Central to this approach is the order 1-Laplacian of a manifold, $\Delta_1$, whose eigen-decomposition into gradient, harmonic, and curl, known as the Helmholtz-Hodge Decomposition, provides a basis for all vector fields on a manifold. We present an estimator for $\Delta_1$, and based on it we develop a variety of applications. Among them, visualization of the principal harmonic, gradient or curl flows on a manifold, smoothing and semi-supervised learning of vector fields, 1-Laplacian regularization. In topological data analysis, we describe the 1st-order analogue of spectral clustering, which amounts to  prime manifold decomposition. Furthermore, from this decomposition a new algorithm for finding shortest independent loops follows. The algorithms are illustrated on a variety of real data sets.

Joint work with  Yu-Chia Chen, Samson Koelle, Vlad Murad, Weicheng Wu, Hanyu Zhang and Ioannis Kevrekidis

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