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In Mergelyan type approximation we uniformly approximate functions on compact sets K by polynomials or rational functions or holomorphic functions on varying open sets containing K. In the present paper we consider analogous approximation,…

Complex Variables · Mathematics 2020-06-04 Sotiris Armeniakos , Giorgos Kotsovolis , Vassili Nestoridis

Let G/H be a pseudo-Riemannian semisimple symmetric space. The tangent bundle T(G/H) contains a maximal G-invariant neighbourhood of the zero section where the adapted complex structure exists. Such neighbourhood is endowed with a canonical…

Complex Variables · Mathematics 2007-05-23 Laura Geatti

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

The purpose of this paper is to present, for all $n\ge 3$, very simple examples of continuous maps $f:M^{n-1} \to M^{n}$ from closed $(n-1)$-manifolds $M^{n-1}$ into closed $n$-manifold $M^n$ such that even though the singular set $S(f)$ of…

Geometric Topology · Mathematics 2009-05-22 D. Repovš , W. Rosicki , A. Zastrow , M. Željko

Using methods from the theory of uniform algebras, we give a simple proof of an approximation result of Sahutoglu and Tikaradze with $L^\infty$-pseudoconvex domains replaced by the open sets for which Gleason's problem is solvable.

Complex Variables · Mathematics 2021-07-20 Timothy G. Clos , Alexander J. Izzo

This paper deals with the existence of algebraic structures on compact Nash sets. We introduce the algebraic-topological notion of asymmetric Nash cobordism between compact Nash sets, and we prove that a compact Nash set is…

Algebraic Geometry · Mathematics 2016-11-21 Riccardo Ghiloni , Alessandro Tancredi

Let X be a complex nonsingular affine algebraic variety, K a holomorphically convex subset of X, and Y a homogeneous variety for some complex linear algebraic group. We prove that a holomorphic map f:K-->Y can be uniformly approximated on K…

Complex Variables · Mathematics 2020-12-23 Jacek Bochnak , Wojciech Kucharz

We prove that every continuous mapping from a separable infinite-dimensional Hilbert space $X$ into $\mathbb{R}^{m}$ can be uniformly approximated by $C^\infty$ smooth mappings {\em with no critical points}. This kind of result can be…

Differential Geometry · Mathematics 2007-05-23 Daniel Azagra , Manuel Cepedello Boiso

Let $X$ be a compact metric space which is locally absolutely retract and let $\phi: C(X)\to C(Y, M_n)$ be a unital homomorphism, where $Y$ is a compact metric space with ${\rm dim}Y\le 2.$ It is proved that there exists a sequence of $n$…

Operator Algebras · Mathematics 2009-09-10 Huaxin Lin

Constructing a similarity graph from a set $X$ of data points in $\mathbb{R}^d$ is the first step of many modern clustering algorithms. However, typical constructions of a similarity graph have high time complexity, and a quadratic space…

Data Structures and Algorithms · Computer Science 2023-10-24 Peter Macgregor , He Sun

Given a closed semi-algebraic set $X \subset \mathbb{R}^n$ and a continuous semi-algebraic mapping $G \colon X \to \mathbb{R}^m,$ it will be shown that there exists an open dense semi-algebraic subset $\mathscr{U}$ of $L(\mathbb{R}^n,…

Algebraic Geometry · Mathematics 2021-04-05 Si Tiep Dinh , Zbigniew Jelonek , Tien Son Pham

For a well-studied family of domination-type problems, in bounded-treewidth graphs, we investigate whether it is possible to find faster algorithms. For sets $\sigma,\rho$ of non-negative integers, a $(\sigma,\rho)$-set of a graph $G$ is a…

Computational Complexity · Computer Science 2023-06-07 Jacob Focke , Dániel Marx , Fionn Mc Inerney , Daniel Neuen , Govind S. Sankar , Philipp Schepper , Philip Wellnitz

This paper addresses the approximation of fractional harmonic maps. Besides a unit-length constraint, one has to tackle the difficulty of nonlocality. We establish weak compactness results for critical points of the fractional Dirichlet…

Numerical Analysis · Mathematics 2021-04-21 Harbir Antil , Sören Bartels , Armin Schikorra

This paper introduces the Simultaneous assignment problem. Let us given a graph with a weight and a capacity function on its edges, and a set of its subgraphs along with a degree upper bound function for each of them. We are also given a…

Data Structures and Algorithms · Computer Science 2023-01-24 Péter Madarasi

In the maximum coverage problem, we are given subsets $T_1, \ldots, T_m$ of a universe $[n]$ along with an integer $k$ and the objective is to find a subset $S \subseteq [m]$ of size $k$ that maximizes $C(S) := \Big|\bigcup_{i \in S}…

Data Structures and Algorithms · Computer Science 2021-05-04 Siddharth Barman , Omar Fawzi , Paul Fermé

In this letter we proved this theorem: \emph{if $F$ be a holomorphic mapping of $T_{\Omega}$ to a mapping manifold $X$ such that for every compact subset $K\subset \Omega$ the mapping $F$ is uniformly continues on $T_{K}$ and $F(T_{K})$ is…

Classical Analysis and ODEs · Mathematics 2010-11-29 Ali Reza Khatoon Abadi , H. R. Rezazadeh , F. Golgoii

We study the problem of approximating the cone of positive semidefinite (PSD) matrices with a cone that can be described by smaller-sized PSD constraints. Specifically, we ask the question: "how closely can we approximate the set of…

Optimization and Control · Mathematics 2022-09-08 Dogyoon Song , Pablo A. Parrilo

The aim of this paper is to investigate the links between ${\cal T}_C$-class algorithms, CQ Algorithm and shrinking projection methods. We show that strong convergence of these algorithms are related to coherent ${\cal T}_C$-class sequences…

Optimization and Control · Mathematics 2009-09-21 Jean-Philippe Chancelier

Semi-supervised semantic segmentation aims to utilize limited labeled images and abundant unlabeled images to achieve label-efficient learning, wherein the weak-to-strong consistency regularization framework, popularized by FixMatch, is…

Computer Vision and Pattern Recognition · Computer Science 2023-12-15 Wentao Pan , Zhe Xu , Jiangpeng Yan , Zihan Wu , Raymond Kai-yu Tong , Xiu Li , Jianhua Yao

We study geometric variations of the discriminating code problem. In the \emph{discrete version} of the problem, a finite set of points $P$ and a finite set of objects $S$ are given in $\mathbb{R}^d$. The objective is to choose a subset…

Computational Geometry · Computer Science 2023-06-30 Sanjana Dey , Florent Foucaud , Subhas C Nandy , Arunabha Sen