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Density estimation is an important technique for characterizing distributions given observations. Much existing research on density estimation has focused on cases wherein the data lies in a Euclidean space. However, some kinds of data are…

Machine Learning · Statistics 2021-07-12 James A. Brofos , Marcus A. Brubaker , Roy R. Lederman

The statistical analysis of covariance matrix data is considered and, in particular, methodology is discussed which takes into account the non-Euclidean nature of the space of positive semi-definite symmetric matrices. The main motivation…

Applications · Statistics 2009-10-12 Ian L. Dryden , Alexey Koloydenko , Diwei Zhou

Semi-Riemannian manifolds that satisfy (homogeneous) linear differential conditions of arbitrary order on the curvature are analyzed. They include, in particular, the spaces with (higher-order) recurrent curvature, (higher-order) symmetric…

Differential Geometry · Mathematics 2024-04-24 José M. M. Senovilla

Graph diffusion models have made significant progress in learning structured graph data and have demonstrated strong potential for predictive tasks. Existing approaches typically embed node, edge, and graph-level features into a unified…

Machine Learning · Computer Science 2025-12-12 Yisen Gao , Xingcheng Fu , Qingyun Sun , Jianxin Li , Xianxian Li

We study random points on the real line generated by the eigenvalues in unitary invariant random matrix ensembles or by more general repulsive particle systems. As the number of points tends to infinity, we prove convergence of the…

Probability · Mathematics 2015-11-11 Kristina Schubert , Martin Venker

The statistical analysis of covariance matrices occurs in many important applications, e.g. in diffusion tensor imaging and longitudinal data analysis. We consider the situation where it is of interest to estimate an average covariance…

Methodology · Statistics 2010-10-20 Ian L. Dryden , Alexey Kolydenko , Diwei Zhou , Bai Li

An analogue of the Stefan-Sussmann Theorem on manifolds with boundary is proven for normal distributions. These distributions contain vectors transverse to the boundary along its entirety. Plain integral manifolds are not enough to…

Differential Geometry · Mathematics 2021-09-13 David Perrella , David Pfefferlé , Luchezar Stoyanov

When expressing a distribution in Euclidean space in spherical co-ordinates, derivation with respect to the radial and angular co-ordinates is far from trivial. Exploring the possibilities of defining a radial derivative of the…

Functional Analysis · Mathematics 2018-01-24 Fred Brackx

A {\em 2-Riemannian manifold} is a differentiable manifold exhibiting a 2-inner product on each tangent space. We first study lower dimensional 2-Riemannian manifolds by giving necessary and sufficient conditions for flatness. Afterward we…

Differential Geometry · Mathematics 2012-01-11 C. A. Morales , M. Vilches

In geosciences, the use of classical Euclidean methods is unsuitable for treating and analyzing some types of data, as this may not belong to a vector space. This is the case for correlation matrices, belonging to a subfamily of symmetric…

Applications · Statistics 2021-10-04 Alvaro Riquelme

The Euclidean formulation of quantum gravity can be interpreted in terms of a probability distribution over Riemannian manifolds. In the context of de Sitter gravity, the statistics of the total volume according to this distribution is…

High Energy Physics - Theory · Physics 2026-05-07 David Blanco , Guillem Pérez-Nadal , Bruno Sivilotti

This paper completes the foundations of neatly integrable normal distribution theory on manifolds with boundary. Normal distributions are those which contain vectors transverse to the boundary along its entirety. The theory is observed to…

Differential Geometry · Mathematics 2021-11-29 David Perrella , David Pfefferlé , Luchezar Stoyanov

We consider diffusion on discrete measure spaces as encoded by Markovian semigroups arising from weighted graphs. We study whether the graph is uniquely determined if the diffusion is given up to order isomorphism. If the graph is recurrent…

Functional Analysis · Mathematics 2014-05-14 Matthias Keller , Daniel Lenz , Marcel Schmidt , Melchior Wirth

After reviewing manifold optimization techniques in applications like MIMO communication systems, phased array beamforming, radar, and control theory, we observed that the Complex Circle Manifold (CCM) is widely employed, yet its…

Optimization and Control · Mathematics 2025-08-12 Amirreza Tabrizi , Mohammad Hadi Mirmohammadi

This paper considers a multivariate spatial random field, with each component having univariate marginal distributions of the skew-Gaussian type. We assume that the field is defined spatially on the unit sphere embedded in $\mathbb{R}^3$,…

Statistics Theory · Mathematics 2017-10-05 Alfredo Alegría , Sandra Caro , Moreno Bevilacqua , Emilio Porcu , Jorge Clarke

Distributions, i.e., subsets of tangent bundles formed by piecing together subspaces of tangent spaces, are commonly encountered in the theory and application of differential geometry. Indeed, the theory of distributions is a fundamental…

Differential Geometry · Mathematics 2023-09-20 Andrew D. Lewis

We introduce novel estimators for computing the curvature, tangent spaces, and dimension of data from manifolds, using tools from diffusion geometry. Although classical Riemannian geometry is a rich source of inspiration for geometric data…

Differential Geometry · Mathematics 2026-02-13 Iolo Jones

This is an intuitive survey of extrinsic and intrinsic notions of convergence of manifolds complete with pictures of key examples and a discussion of the properties associated with each notion. We begin with a description of three extrinsic…

Differential Geometry · Mathematics 2013-04-08 Christina Sormani

The n-dimensional Lorentzian manifolds with vanishing second covariant derivative of the Riemann tensor (2-symmetric spacetimes) are characterized and classified. The main result is that either they are locally symmetric or they have a…

Differential Geometry · Mathematics 2008-10-24 José M. M. Senovilla

Consensus algorithms are popular distributed algorithms for computing aggregate quantities, such as averages, in ad-hoc wireless networks. However, existing algorithms mostly address the case where the measurements lie in a Euclidean space.…

Dynamical Systems · Mathematics 2012-02-02 Roberto Tron , Bijan Afsari , René Vidal