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Any affine map on the (n+1)-dimensional Euclidean space gives rise to a natural map on the n-dimensional sphere whose dynamical aspects are not so well-studied in the literature. We explore the dynamical aspects of these maps by…

Dynamical Systems · Mathematics 2023-09-12 Manoj Choudhuri , Gianluca Faraco , Alok Kumar Yadav

We present a full geometric characterization of the $1$-dimensional (semialgebraic) images $S$ of either $n$-dimensional closed balls $\overline{\mathcal B}_n\subset{\mathbb R}^n$ or $n$-dimensional spheres ${\mathbb S}^n\subset{\mathbb…

Algebraic Geometry · Mathematics 2025-07-09 José F. Fernando

We say that a metric graph is uniformly bounded if the degrees of all vertices are uniformly bounded and the lengths of edges are pinched between two positive constants; a metric space is approximable by a uniform graph if there is one…

Metric Geometry · Mathematics 2013-06-25 Dmitri Burago , Sergei Ivanov

Let S be a compact surface, and M be the double of a handlebody. Given a homotopy class of maps from S to M inducing an isomorphism of fundamental groups, we describe a canonical uniformly lipschitz retraction of the sphere graph of M to…

Geometric Topology · Mathematics 2016-07-27 Brian H. Bowditch , Francesca Iezzi

We introduce and study a class of Thurston maps from the 2-sphere to itself which we call nearly Euclidean Thurston (NET) maps. These are simple generalizations of Euclidean Thurston maps.

Dynamical Systems · Mathematics 2012-04-17 James W. Cannon , William J. Floyd , Walter R. Parry , Kevin M. Pilgrim

We construct an explicit family of stable proper weak biharmonic maps from the unit ball $B^m$, $m\geq 5$, to Euclidean spheres. To the best of the authors knowledge this is the first example of a stable proper weak biharmonic map from at…

Differential Geometry · Mathematics 2025-07-10 Volker Branding , Anna Siffert

We prove that holomorphic maps from an open subset of a complex smooth projective curve to a complex smooth projective rationally simply connected variety can be approximated by algebraic maps for the compact-open topology. This theorem can…

Algebraic Geometry · Mathematics 2025-08-22 Olivier Benoist , Olivier Wittenberg

Let X be a closed surface of genus two embedded in the 3-sphere. Then X inherits a metric and an orientation, which give an almost complex structure, which automatically integrates to a genuine complex structure, making X a Riemann surface.…

Complex Variables · Mathematics 2016-07-22 Neil Strickland

Let $X$ be an analytic subset of $U\times C^n$ of pure dimension $k$ such that the projection of $X$ onto $U$ is a proper mapping, where $U$ is a Runge domain in $C^k$. We show that $X$ can be approximated by algebraic sets.

Complex Variables · Mathematics 2009-05-13 Marcin Bilski

In this paper we first prove a characterization formula for biharmonic maps in Euclidean spheres and, as an application, we construct a family of biharmonic maps from a flat $2$-dimensional torus $\mathbb{T}$ into the $3$-dimensional unit…

Differential Geometry · Mathematics 2022-05-27 Rareş Ambrosie , Cezar Oniciuc , Ye-Lin Ou

We prove a generalisation of Rudin's theorem on proper holomorphic maps from the unit ball to the case of proper holomorphic maps from pseudoellipsoids.

Complex Variables · Mathematics 2014-03-04 Cristina Giannotti , Andrea Spiro

Special generic maps are smooth maps between smooth manifolds with only definite fold points as their singularities. The problem of whether a closed $n$-manifold admits a special generic map into Euclidean $p$-space for $1 \leq p \leq n$…

Geometric Topology · Mathematics 2020-09-15 Dominik Wrazidlo

We investigate the problem of approximating a regular Sasakian structure by CR immersions in a standard sphere. Namely, we show that this is always possible for compact Sasakian manifolds. Moreover, we prove an approximation result for…

Differential Geometry · Mathematics 2024-02-21 Giovanni Placini

Consider an analytic map of a neighborhood of 0 in a vector space to a Euclidean space. Suppose that this map takes all germs of lines passing through 0 to germs of circles. Such a map is called rounding. We introduce a natural equivalence…

Metric Geometry · Mathematics 2007-05-23 Vladlen Timorin

In this work we compare the semialgebraic subsets that are images of regulous maps with those that are images of regular maps. Recall that a map f : R n $\rightarrow$ R m is regulous if it is a rational map that admits a continuous…

Algebraic Geometry · Mathematics 2017-11-29 José Fernando , Goulwen Fichou , Ronan Quarez , Carlos Ueno

We prove that if E a subset of an n-dimensional manifold, then every continuous R^n-valued map on E that is zero-free on the interior of E can be approximated in the fine topology, and hence, in particular, in the uniform topology, by a…

General Topology · Mathematics 2026-01-12 Alexander J. Izzo

We present robust algorithms for set operations and Euclidean transformations of curved shapes in the plane using approximate geometric primitives. We use a refinement algorithm to ensure consistency. Its computational complexity is…

Computational Geometry · Computer Science 2012-10-03 Victor Milenkovic , Elisha Sacks , Steven Trac

In this article, using the computer, are enumerated all locally-rigid packings by $N$ congruent circles (spherical caps) on the unit sphere ${\Bbb S}^2 $ with $N < 12.$ This is equivalent to the enumeration of irreducible spherical contact…

Metric Geometry · Mathematics 2013-12-20 Oleg Musin , Alexey Tarasov

Given topological spaces X and Y, a fundamental problem of algebraic topology is understanding the structure of all continuous maps X -> Y . We consider a computational version, where X, Y are given as finite simplicial complexes, and the…

Computational Geometry · Computer Science 2014-01-31 Martin Čadek , Marek Krčál , Jiří Matoušek , Francis Sergeraert , Lukáš Vokřínek , Uli Wagner

It is known that every closed curve of length \leq 4 in R^n (n>0) can be surrounded by a sphere of radius 1, and that this is the best bound. Letting S denote the circle of circumference 4, with the arc-length metric, we here express this…

Metric Geometry · Mathematics 2021-10-15 George M. Bergman