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Related papers: Isospectral Metrics on Projective Spaces

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In this paper we use the relationship between conformal metrics on the sphere and horospherically convex hypersurfaces in the hyperbolic space for giving sufficient conditions on a conformal metric to be radial under some constrain on the…

Differential Geometry · Mathematics 2008-11-17 Jose M. Espinar

We prove that there exists a metric of positive curvature in a three-sphere which admits a given torus knot as a closed geodesic.We also sketch a construction of a metric in a four sphere, very likely of positive curvature, which admits a…

dg-ga · Mathematics 2008-02-03 Alexander Reznikov

We define inductively isometric embeddings of $\mb{P}^n(\mb{R})$ and $\mb{P}^n(\mb{C})$ (with their canonical metrics conveniently scaled) into the standard unit sphere, which present the former as the restriction of the latter to the set…

Differential Geometry · Mathematics 2018-12-27 Santiago R Simanca

We examine homogeneous metrics on spheres and determine which ones have positive sectional curvature. The answer is subtle and surprisingly difficult to prove. In some cases we also determine their pinching constants. This completes the…

Differential Geometry · Mathematics 2009-09-29 Luigi Verdiani , Wolfgang Ziller

We examine three-dimensional metric deformations based on a tetrad transformation through the action the matrices of scalar fields. We describe by this approach to deformation the results obtained by Coll et al. in [1], where it is stated…

General Relativity and Quantum Cosmology · Physics 2015-02-05 Daniela Pugliese , Cosimo Stornaiolo

Three-dimensional isospectral systems are constructed using the framework of supersymmetric quantum mechanics. In case the supercharge of first order in momentum is used, it is proved that the constructed systems reduce to a trivial…

Quantum Physics · Physics 2009-11-13 Yoshihide Yamada

In this paper, we focus on homogeneous spaces which are constructed from two strongly isotropy irreducible spaces, and prove that any geodesic orbit metric on these spaces is naturally reductive.

Differential Geometry · Mathematics 2020-12-15 Huibin Chen , Zhiqi Chen , Fuhai Zhu

Projective metrics on vector spaces over finite fields, introduced by Gabidulin and Simonis in 1997, generalize classical metrics in coding theory like the Hamming metric, rank metric, and combinatorial metrics. While these specific metrics…

Metric Geometry · Mathematics 2025-05-13 Gabor Riccardi , Hugo Sauerbier Couvée

For any positive integer $r$, we construct a smooth complex projective rational surface which has at least $r$ real forms not isomorphic over $\mathbb{R}$.

Algebraic Geometry · Mathematics 2022-02-11 Anna Bot

A projective rectangle is like a projective plane that has different lengths in two directions. We develop the basic theory of projective rectangles including incidence properties, projective subplanes, configuration counts, a partial…

Combinatorics · Mathematics 2024-07-17 Rigoberto Florez , Thomas Zaslavsky

In this work, we present an adaptation of the classical stereographic projection, originally formulated for the sphere, now considering the context of the ellipsoid and the elliptic paraboloid. We begin by constructing the stereographic…

Differential Geometry · Mathematics 2025-06-11 W. F. C. Barboza , T. F. Cruz , R. B. Leal

Let $\mathbb{Q}_3$ be the complex 3-quadric endowed with its standard complex conformal structure. We study the complex conformal geometry of isotropic curves in $\mathbb{Q}_3$. By an isotropic curve we mean a nonconstant holomorphic map…

Differential Geometry · Mathematics 2021-10-07 Emilio Musso , Lorenzo Nicolodi

We contribute to the program of extending computable structure theory to the realm of metric structures by investigating lowness for isometric isomorphism of metric structures. We show that lowness for isomorphism coincides with lowness for…

Logic · Mathematics 2019-11-15 Johanna N. Y. Franklin , Timothy H. McNicholl

We describe a construction of Riemannian metrics of nonnegative sectional curvature on a closed smooth nonorientable 4-manifold with fundamental group of order two that realizes a homotopy class that was not previously known to contain…

Differential Geometry · Mathematics 2018-12-14 Rafael Torres

This paper is concerned with the construction of special metrics on non-compact 4-manifolds which arise as resolutions of complex orbifold singularities. Our study is close in spirit to the construction of the hyperkaehler gravitational…

Differential Geometry · Mathematics 2015-06-26 David M. J. Calderbank , Michael A. Singer

This paper contains an attempt to formulate rigorously and to check predictions in enumerative geometry of curves following from Mirror Symmetry. The main tool is a new notion of stable map. We give an outline of a contsruction of…

High Energy Physics - Theory · Physics 2008-02-03 M. Kontsevich

While the notion of isometric deformations of surfaces is straightforward for surfaces with Euclidean metric, a corresponding notion in isotropic space has been missing. By making Gauss' Theorema Egregium a necessary condition we develop a…

Differential Geometry · Mathematics 2025-04-16 Christian Müller , Helmut Pottmann

We study the structure of stationary and axisymmetric metrics solving the vacuum Einstein equations of General Relativity in four and higher dimensions, building on recent work in hep-th/0408141. We write the Einstein equations in a new…

High Energy Physics - Theory · Physics 2009-11-11 Troels Harmark , Poul Olesen

We develop the structure theory of full isometry groups of locally compact non-positively curved metric spaces. Amongst the discussed themes are de Rham decompositions, normal subgroup structure and characterising properties of symmetric…

Group Theory · Mathematics 2010-01-18 P. -E. Caprace , N. Monod

We present a certified algorithm that takes a smooth algebraic curve in $\mathbb{R}^n$ and computes an isotopic approximation for a generic projection of the curve into $\mathbb{R}^2$. Our algorithm is designed for curves given implicitly…

Symbolic Computation · Computer Science 2025-06-12 Michael Burr , Michael Byrd , Kisun Lee