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We tour several Euclidean properties of Poncelet triangles inscribed in an ellipse and circumscribing the incircle, including loci of triangle centers and envelopes of key objects. We also show that a number of degenerate behaviors are…

Dynamical Systems · Mathematics 2025-12-29 Mark Helman , Ronaldo A. Garcia , Dan Reznik

The goal of this paper is an analysis of the geometry of billiards in ellipses, based on properties of confocal central conics. The extended sides of the billiards meet at points which are located on confocal ellipses and hyperbolas. They…

Metric Geometry · Mathematics 2021-05-20 H. Stachel

The overlap graphs of subtrees in a tree (SOGs) generalise many other graphs classes with set representation characterisations. The complexity of recognising SOGs in open. The complexities of recognising many subclasses of SOGs are known.…

Computational Complexity · Computer Science 2022-02-04 Jessica Enright , Martin Pergel

Amoebas are projections of complex algebraic varieties in the algebraic torus under a Log-absolute value map, which have connections to various mathematical subjects. While amoebas of hypersurfaces have been intensively studied in recent…

Combinatorics · Mathematics 2017-02-07 Martina Juhnke-Kubitzke , Timo de Wolff

Geometric algebra is an optimal frame work for calculating with vectors. The geometric algebra of a space includes elements that represent all the its subspaces (lines, planes, volumes, ...). Conformal geometric algebra expands this…

Computer Vision and Pattern Recognition · Computer Science 2013-06-07 Eckhard Hitzer

We show that the relations which define the algebras of the quantum Euclidean planes $\b{R}^N_q$ can be expressed in terms of projections provided that the unique central element, the radial distance from the origin, is fixed. The resulting…

Quantum Algebra · Mathematics 2015-06-26 Giovanni Landi , John Madore

We study geometric structures on the complement of a toric mirror arrangement associated with a root system. Inspired by those special hypergeometric functions found by Heckman-Opdam, as well as the work of Couwenberg-Heckman-Looijenga on…

Algebraic Geometry · Mathematics 2018-08-31 Dali Shen

Enumerative algebraic geometry deals with problems of counting geometric objects defined algebraically, An important class of enumerative problems is that of counting curves: given a class of curves in some projective variety defined by…

Algebraic Geometry · Mathematics 2019-03-05 Yaniv Ganor

We introduce the spherical wedge billiard, a dynamical system consisting of a particle moving along a geodesic on a closed non-Euclidean surface of a spherical wedge. We derive the analytic form of the corresponding Poincar\'e map and find…

Chaotic Dynamics · Physics 2022-11-09 Tomáš Tyc , Darek Cidlinský

The Reeb space of a smooth function is a topological and combinatoric object and fundamental and important in understanding topological and geometric properties of the manifold of the domain. It is the graph and a topological space endowed…

General Topology · Mathematics 2024-12-29 Naoki Kitazawa

Consider a smooth map from a neighborhood of the origin in a real vector space to a neighborhood of the origin in a Euclidean space. Suppose that this map takes all germs of lines passing through the origin to germs of Euclidean circles, or…

Metric Geometry · Mathematics 2007-05-23 Vladlen Timorin

Various algebraic structures in geometry and group theory have appeared to be governed by certain universal rings. Examples include: the cohomology rings of Hilbert schemes of points on projective surfaces and quasi-projective surfaces; the…

Quantum Algebra · Mathematics 2007-05-23 Weiqiang Wang

The torus T of projective space also acts on the Hilbert scheme of subschemes of projective space. The T-graph of the Hilbert scheme has vertices the fixed points of this action, and edges connecting pairs of fixed points in the closure of…

Algebraic Geometry · Mathematics 2023-12-07 Diane Maclagan , Rob Silversmith

The enduring legacy of Euclidean geometry underpins classical machine learning, which, for decades, has been primarily developed for data lying in Euclidean space. Yet, modern machine learning increasingly encounters richly structured data…

We investigate the structure of the generalized Weierstrass semigroups at several points on a curve defined over a finite field. We present a description of these semigroups that enables us to deduce properties concerned with the…

Algebraic Geometry · Mathematics 2025-01-17 Julio José Moyano-Fernández , Wanderson Tenório , Fernando Torres

We show that every multilinear map between Euclidean spaces induces a unique, continuous, Minkowski multilinear map of the corresponding real cones of zonoids. Applied to the wedge product of the exterior algebra of a Euclidean space, this…

Metric Geometry · Mathematics 2024-01-10 Paul Breiding , Peter Bürgisser , Antonio Lerario , Léo Mathis

Given a reflection group $G$ acting on a complex vector space $V$, a reflection map is the composition of an embedding $X \hookrightarrow V$ with the orbit map $V\to\mathbb C^p$ that maps a $G$-orbit to a point. Reflection maps can be very…

Algebraic Geometry · Mathematics 2017-10-24 G. Peñafort-Sanchis

Let a $R$-body be a closed set, complement of union of open balls of radius $R$ in the Euclidean space. Properties generalizing similar ones for convex sets are proved for the family of $R$-bodies; properties for the family of sets…

Metric Geometry · Mathematics 2024-06-25 Marco Longinetti , Paolo Manselli , Adriana Venturi

Regions-based theories of space aim -- among others -- to define points in a geometrically appealing way. The most famous definition of this kind is probably due to Whitehead. However, to conclude that the objects defined are points indeed,…

Logic · Mathematics 2023-10-03 Rafał Gruszczyński

We introduce a new class of surfaces in Euclidean $3$-space, called surfaces of osculating circles, using the concept of osculating circle of a regular curve. These surfaces contain a uniparametric family of planar lines of curvature. In…

Differential Geometry · Mathematics 2021-12-08 Rafael López , Cetin Camci , Ali Ucum , Kazim Ilarslan