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Related papers: Grassmann angles between real or complex subspaces

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The real Grassmannian is both a projective variety (via Pl\"ucker coordinates) and an affine variety (via orthogonal projections). We connect these two representations, and we develop the commutative algebra of the latter variety. We…

Algebraic Geometry · Mathematics 2024-07-08 Karel Devriendt , Hannah Friedman , Bernhard Reinke , Bernd Sturmfels

The purpose of this paper is twofold. On a technical side, we propose an extension of the Hausdorff distance from metric spaces to spaces equipped with asymmetric distance measures. Specifically, we focus on the family of Bregman…

Machine Learning · Computer Science 2025-04-11 Tuyen Pham , Hana Dal Poz Kouřimská , Hubert Wagner

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

Sparsity-based representations have recently led to notable results in various visual recognition tasks. In a separate line of research, Riemannian manifolds have been shown useful for dealing with features and models that do not lie in…

Machine Learning · Computer Science 2015-05-21 Mehrtash Harandi , Richard Hartley , Chunhua Shen , Brian Lovell , Conrad Sanderson

Quantum states defined over a parameter space form a Grassmann manifold. To capture the geometry of the associated gauge structure, gauge-invariant quantities are essential. We employ the projector of a multilevel system to quantify the…

Mesoscale and Nanoscale Physics · Physics 2025-10-30 Shin-Ming Huang , Dimitrios Giataganas

We consider a generalized angle in complex normed vector spaces. Its definition corresponds to the definition of the well known Euclidean angle in real inner product spaces. Not surprisingly it yields complex values as `angles'. This…

Functional Analysis · Mathematics 2015-06-17 Volker W. Thürey

We construct vast families of orthogonal operators obeying pentagon relation in a direct sum of three n-dimensional vector spaces. As a consequence, we obtain pentagon relations in Grassmann algebras, making a far reaching generalization of…

Mathematical Physics · Physics 2013-04-11 Igor G. Korepanov , Nurlan M. Sadykov

We will pursue a way of building up an algebraic structure that involves, in a mathematical abstract way, the well known Grassmann variables. The problem arises when we tried to understand the grassmannian polynomial expansion on the scope…

Mathematical Physics · Physics 2007-05-23 Ricardo M Bentin

Hausdorff relation, topologically identifying points in a given space, belongs to elementary tools of modern mathematics. We show that if subtle enough mathematical methods are used to analyze this relation, the conclusions may be…

Mathematical Physics · Physics 2015-05-19 Michael Heller , Leszek Pysiak , Wieslaw Sasin

In this work, we present a novel and practical approach to address one of the longstanding problems in computer vision: 2D and 3D affine invariant feature matching. Our Grassmannian Graph (GrassGraph) framework employs a two stage procedure…

Computer Vision and Pattern Recognition · Computer Science 2016-02-05 Mark Moyou , John Corring , Adrian Peter , Anand Rangarajan

Flag manifolds are generalizations of projective spaces and other Grassmannians: they parametrize flags, which are nested sequences of subspaces in a given vector space. These are important objects in algebraic and differential geometry,…

Differential Geometry · Mathematics 2021-08-06 Brenden Balch , Chris Peterson , Clayton Shonkwiler

The aim of this paper is to present a short introduction to supergeometry on pure odd supermanifolds. (Pseudo)differential forms, Cartan calculus (DeRham differential, Lie derivative, "inner" product), metric, inner product, Killing's…

Differential Geometry · Mathematics 2010-01-23 Denis Kochan

We identify a region $\Bbb{W}_{\f{1}{3}}$ in a Grassmann manifold $\grs{n}{m}$, not covered by a usual matrix coordinate chart, with the following important property. For a complete $n-$submanifold in $\ir{n+m} \, (n\ge 3, m\ge2)$ with…

Differential Geometry · Mathematics 2011-09-30 J. Jost , Y. L. Xin , Ling Yang

We introduce a theoretical framework for performing statistical tasks---including, but not limited to, averaging and principal component analysis---on the space of (possibly asymmetric) matrices with arbitrary entries and sizes. This is…

Metric Geometry · Mathematics 2020-04-24 Samir Chowdhury , Tom Needham

We derive the equation of matter density perturbations on sub-horizon scales around a flat Friedmann-Lema\^\i tre-Robertson-Walker background for the general Lagrangian density $f(R,\GB)$ that is a function of a Ricci scalar $R$ and a…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-13 Antonio De Felice , Teruaki Suyama

We introduce the orthogonal Grassmannian as a novel kinematic space for describing correlators of massless spinning fields in de Sitter space. By automatically encoding the constraints of conformal symmetry and current conservation, the…

High Energy Physics - Theory · Physics 2026-02-10 Mattia Arundine , Daniel Baumann , Mang Hei Gordon Lee , Guilherme L. Pimentel , Facundo Rost

We determine the invariants characterizing the $Sp(n)$-orbits in the real Grassmannian $Gr^\R(2k,4n)$ of the $2k$-dimensional complex and $\Sigma$-complex subspaces of a $4n$-dimensional Hermitian quaternionic vector space. A…

Differential Geometry · Mathematics 2022-02-01 Massimo Vaccaro

We propose a conjugate gradient type optimization technique for the computation of the Karcher mean on the set of complex linear subspaces of fixed dimension, modeled by the so-called Grassmannian. The identification of the Grassmannian…

Differential Geometry · Mathematics 2012-09-17 Knut Hüper , Martin Kleinsteuber , Hao Shen

There are two basic angles associated with a pair of linear subspaces: the Diximier angle and the Friedrichs angle. The Dixmier angle of the pair of orthogonal complements is the same as the Dixmier angle of the original pair provided that…

Functional Analysis · Mathematics 2021-09-23 Heinz H. Bauschke , Hui Ouyang , Xianfu Wang

We obtain the following version of Lidskii theorem. Let L, M, N be p-dimensional subspaces in R^n. Let \psi_j be the angles between L and M, let \phi_j be the angles between M and N, and let \theta_j be the angles between L and N. Consider…

Differential Geometry · Mathematics 2013-01-15 Yurii A. Neretin