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Correlation matrices are used in many domains of neurosciences such as fMRI, EEG, MEG. However, statistical analyses often rely on embeddings into a Euclidean space or into Symmetric Positive Definite matrices which do not provide intrinsic…

Differential Geometry · Mathematics 2021-03-09 Yann Thanwerdas , Xavier Pennec

We develop a curvilinear invariant set of the diffusion tensor which may be applied to Diffusion Tensor Imaging measurements on tissues and porous media. This new set is an alternative to the more common invariants such as fractional…

Biological Physics · Physics 2014-01-03 Robin A. Damion , Aleksandra Radjenovic , Eileen Ingham , Zhongmin Jin , Michael E. Ries

We establish the mathematical fundamentals for a unified description of curvature, torsion, and non-metricity 2-forms in the way extending the so-called M\"{o}bius representation of the affine group, which is the method to convert the…

General Relativity and Quantum Cosmology · Physics 2024-10-07 Kyosuke Tomonari

The floating body approach to affine surface area is adapted to a holomorphic context providing an alternate approach to Fefferman's invariant hypersurface measure.

Complex Variables · Mathematics 2007-05-23 David E. Barrett

This contribution is the first in a series of three: it reports on the construction of (a fine sheaf of) diffeomorphism invariant Colombeau algebras on open sets of Eucildean space, which completes earlier approaches. Part II and III will…

Functional Analysis · Mathematics 2007-05-23 Roland Steinbauer

Affine transformation is one of the most common transformations in nature, which is an important issue in the field of computer vision and shape analysis. And affine transformations often occur in both shape and color space simultaneously,…

Computer Vision and Pattern Recognition · Computer Science 2019-11-20 You Hao , Hanlin Mo , Qi Li , He Zhang , Hua Li

In its most general form, the recognition problem in Riemannian geometry asks for the identification of an unknown Riemannian manifold via measurements of metric invariants on the manifold. We introduce a new infinite sequence of…

Differential Geometry · Mathematics 2016-09-06 Karsten Grove , Steen Markvorsen

In this article we introduce a diffeomorphism-invariant Riemannian metric on the space of vector valued one-forms. The particular choice of metric is motivated by potential future applications in the field of functional data and shape…

Differential Geometry · Mathematics 2020-09-04 Martin Bauer , Eric Klassen , Stephen C. Preston , Zhe Su

We present a Riemannian framework for linear and quadratic discriminant classification on the tangent plane of the shape space of curves. The shape space is infinite dimensional and is constructed out of square root velocity functions of…

Invariants withstand transformations and, therefore, represent the essence of objects or phenomena. In mathematics, transformations often constitute a group action. Since the 19th century, studying the structure of various types of…

Symbolic Computation · Computer Science 2024-12-19 Irina A. Kogan

The integrability condition called shape invariance is shown to have an underlying algebraic structure and the associated Lie algebras are identified. These shape-invariance algebras transform the parameters of the potentials such as…

Quantum Physics · Physics 2009-10-30 A. B. Balantekin

Geometric frameworks for analyzing curves are common in applications as they focus on invariant features and provide visually satisfying solutions to standard problems such as computing invariant distances, averaging curves, or registering…

Methodology · Statistics 2025-11-24 Perrine Chassat , Juhyun Park , Nicolas Brunel

Basic aspects of the equiaffine geometry of level sets are developed systematically. As an application there are constructed families of $2n$-dimensional nondegenerate hypersurfaces ruled by $n$-planes, having equiaffine mean curvature…

Differential Geometry · Mathematics 2017-11-06 Daniel J. F. Fox

The metrizability problem for a symmetric affine connection on a manifold, invariant with respect to a group of diffeomorphisms G, is considered. We say that the connection is G-metrizable, if it is expressible as the Levi-Civita connection…

Mathematical Physics · Physics 2012-02-28 Erico Tanaka , Demeter Krupka

The covering of the affine symmetry group, a semidirect product of translations and special linear transformations, in $D \geq 3$ dimensional spacetime is considered. Infinite dimensional spinorial representations on states and fields are…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Djordje Sijacki

This work sets the statistical affine shape theory in the context of real normed division algebras. The general densities apply for every field: real, complex, quaternion, octonion, and for any noncentral and non-isotropic elliptical…

Statistics Theory · Mathematics 2010-12-30 Jose A. Diaz-Garcia , Francisco J. Caro-Lopera

The problem of classification of cubic homogeneous Finslerian 3D metrics with respect to their isometries is considered. It is shown, that there are 6 different general affine types of such metrics. Algebras of isometries are presented in…

Mathematical Physics · Physics 2010-11-25 Sergey S. Kokarev

We introduce a new approach for computing curvature of sub-Riemannian manifolds. Curvature is here meant as symplectic invariants of Jacobi curves of geodesics, as introduced by Zelenko and Li. We describe how they can be expressed using a…

Differential Geometry · Mathematics 2020-03-24 Erlend Grong

Affine invariant points and maps for sets were introduced by Gr\"unbaum to study the symmetry structure of convex sets. We extend these notions to a functional setting. The role of symmetry of the set is now taken by evenness of the…

Functional Analysis · Mathematics 2021-04-06 Ben Li , Carsten Schütt , Elisabeth M. Werner

Graph diffusion models achieve state-of-the-art performance in graph generation but suffer from quadratic complexity in the number of nodes -- and much of their capacity is wasted modeling the absence of edges in sparse graphs. Inspired by…

Machine Learning · Computer Science 2026-05-13 Antoine Siraudin , Christopher Morris