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Let k be a perfect field and let K/k be a finite extension of fields. An arithmetic noncommutative projective line is a noncommutative space equal to the projectivization of the noncommutative symmetric algebra of a k-central two -sided…

Quantum Algebra · Mathematics 2014-05-30 Adam Nyman

By the quantization condition compact quantizable Kaehler manifolds can be embedded into projective space. In this way they become projective varieties. The quantum Hilbert space of the Berezin-Toeplitz quantization (and of the geometric…

Quantum Algebra · Mathematics 2007-05-23 Martin Schlichenmaier

In shape analysis, the concept of shape spaces has always been vague, requiring a case-by-case approach for every new type of shape. In this paper, we give a general definition for an abstract space of shapes in a manifold. This notion…

Differential Geometry · Mathematics 2015-04-09 Sylvain Arguillère

This paper deals with projective shape analysis, which is a study of finite configurations of points modulo projective transformations. The topic has various applications in machine vision. We introduce a convenient projective shape space,…

Statistics Theory · Mathematics 2007-06-13 Kanti V. Mardia , Vic Patrangenaru

We define symmetric spaces in arbitrary dimension and over arbitrary non-discrete topological fields $\K$, and we construct manifolds and symmetric spaces associated to topological continuous quasi-inverse Jordan pairs and -triple systems.…

Group Theory · Mathematics 2007-05-23 Wolfgang Bertram , Karl-Hermann Neeb

We investigate the enumerative geometry of point configurations in projective space. We define "projective configuration counts": these enumerate configurations of points in projective space such that certain specified subsets are in fixed…

Algebraic Geometry · Mathematics 2026-02-09 Alex Fink , Navid Nabijou , Rob Silversmith

Weighted projective space arises when we consider the usual geometric definition for projective space and allow for non-trivial weights. On its own, this extra freedom gives rise to more than enough interesting phenomena, but it is the fact…

Algebraic Geometry · Mathematics 2020-11-04 Timothy Hosgood

This paper is a self-contained exposition of the geometry of symmetric positive-definite real $n\times n$ matrices $\operatorname{SPD}(n)$, including necessary and sufficent conditions for a submanifold $\mathcal{N}…

Differential Geometry · Mathematics 2024-06-06 Alice Barbara Tumpach , Gabriel Larotonda

Riemannian neural networks, which extend deep learning techniques to Riemannian spaces, have gained significant attention in machine learning. To better classify the manifold-valued features, researchers have started extending Euclidean…

Machine Learning · Computer Science 2024-10-03 Ziheng Chen , Yue Song , Rui Wang , Xiaojun Wu , Nicu Sebe

We prove that the space of convex real projective structures on a surface of genus $g\ge 2$ admits a mapping class group invariant K\"ahler metric where Teichm\"uller space with Weil-Petersson metric is a totally geodesic complex…

Geometric Topology · Mathematics 2016-06-06 Inkang Kim , Genkai Zhang

This article provides an overview of various notions of shape spaces, including the space of parametrized and unparametrized curves, the space of immersions, the diffeomorphism group and the space of Riemannian metrics. We discuss the…

Differential Geometry · Mathematics 2014-10-07 Martin Bauer , Martins Bruveris , Peter W. Michor

One says that a smooth manifold M is a pseudo-Riemannian manifold of signature (p,q) if the tangent bundle TM is equipped with a smooth non-degenerate symmetric inner product g of signature (p,q). Similarly one says that M is an affine…

Differential Geometry · Mathematics 2007-08-10 M. Brozos-Vazquez , P. Gilkey , S. Nikcevic , U. Simon

We define a partition of the space of projectively flat metrics in three classes according to the sign of the Chern scalar curvature; we prove that the class of negative projectively flat metrics is empty, and that the class of positive…

Differential Geometry · Mathematics 2021-03-25 Simone Calamai

We construct Grassmann spaces associated with the incidence geometry of regular and tangential subspaces of a symplectic copolar space, show that the underlying metric projective space can be recovered in terms of the corresponding…

Combinatorics · Mathematics 2012-03-16 M. Prażmowska , K. Prażmowski , M. Żynel

Among plenty of applications, low-dimensional homogeneous spaces appear in cosmological models as both, classical factor spaces of multidimensional geometry and minisuperspaces in canonical quantization. Here a new tool to restrict their…

General Relativity and Quantum Cosmology · Physics 2016-08-31 M. Rainer

In this paper we study the topology of the spaces Hol(M,P{n},k) of (basepoint preserving) holomorphic maps of a given degree k from a Riemann surface M of genus g>0 into the n-th complex projective space P{n}, n>0. Using symmetric products…

alg-geom · Mathematics 2007-05-23 S. Kallel , R. J. Milgram

We study the six-dimensional pseudo-Riemannian spaces with two time-like coordinates that admit non-homothetic infinitesimal projective transformations. The metrics are manifestly obtained and the projective group properties are determined.…

Differential Geometry · Mathematics 2015-06-26 Zolfira Zakirova

We discuss representations of the projective line over a ring $R$ with 1 in a projective space over some (not necessarily commutative) field $K$. Such a representation is based upon a $(K,R)$-bimodule $U$. The points of the projective line…

Algebraic Geometry · Mathematics 2024-02-13 Andrea Blunck , Hans Havlicek

In this paper, we study the problem of facial expression recognition using a novel space-time geometric representation. We describe the temporal evolution of facial landmarks as parametrized trajectories on the Riemannian manifold of…

Computer Vision and Pattern Recognition · Computer Science 2017-07-21 Anis Kacem , Mohamed Daoudi , Boulbaba Ben Amor , Juan Carlos Alvarez-Paiva

Each vector space that is endowed with a quadratic form determines its Clifford algebra. This algebra, in turn, contains a distinguished group, known as the Lipschitz group. We show that only a quotient of this group remains meaningful in…

Metric Geometry · Mathematics 2024-02-02 Hans Havlicek