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We show that points on $C^{1}$ curves which are badly approximable by rationals in a number field form a winning set in the sense of W. M. Schmidt. As a consequence, we obtain a number field version of Schmidt's conjecture.

Dynamical Systems · Mathematics 2019-02-20 Manfred Einsiedler , Anish Ghosh , Beverly Lytle

For any irrational real number xi, let lambda(xi) denote the supremum of all real numbers lambda such that, for each sufficiently large X, the inequalities |x_0| < X, |x_0*xi-x_1| < X^{-lambda} and |x_0*xi^2-x_2| < X^{-lambda} admit a…

Number Theory · Mathematics 2013-01-07 Damien Roy

We study the best coapproximation problem in Banach spaces, by using Birkhoff-James orthogonality techniques. We introduce two special types of subspaces, christened the anti-coproximinal subspaces and the strongly anti-coproximinal…

Functional Analysis · Mathematics 2024-08-14 Shamim Sohel , Souvik Ghosh , Debmalya Sain , Kallol Paul

In [2] we characterized in terms of a quadratic growth condition various metric regularity properties of the subdifferential of a lower semicontinuous convex function acting in a Hilbert space. Motivated by some recent results in [16] where…

Optimization and Control · Mathematics 2015-07-01 Francisco J. Aragón Artacho , Michel H. Geoffroy

We introduce and study some families of groups whose irreducible characters take values on quadratic extensions of the rationals. We focus mostly on a generalization of inverse semi-rational groups, which we call uniformly semi-rational…

Group Theory · Mathematics 2025-07-01 Ángel del Río , Marco Vergani

In this note, we give a new necessary condition for the existence of non-trivial partitions of a finite vector space. Precisely, we prove that, if V is a finite vector space over a field of order q, then the number of the subspaces of…

Combinatorics · Mathematics 2009-02-19 Antonino Giorgio Spera

Let V be a vector space of dimension n over the finite field F_q, where q is odd, and let Symm(V) denote the space of symmetric bilinear forms defined on V x V. We investigate constant rank r subspaces of Symm(V) in this paper. We have…

Rings and Algebras · Mathematics 2016-02-10 Rod Gow

We show that complex Fano hypersurfaces can have arbitrarily large degrees of irrationality. More precisely, if we fix a Fano index e, then the degree of irrationality of a very general complex Fano hypersurface of index e and dimension n…

Algebraic Geometry · Mathematics 2021-11-11 Nathan Chen , David Stapleton

We discuss the use of matrices for providing sequences of rationals that approximate algebraic irrationalities. In particular, we study the regular representation of algebraic extensions, proving that ratios between two entries of the…

Number Theory · Mathematics 2020-03-10 Stefano Barbero , Umberto Cerruti , Nadir Murru

In a complete metric space that is equipped with a doubling measure and supports a Poincar\'e inequality, we study strict subsets, i.e. sets whose variational capacity with respect to a larger reference set is finite, in the case $p=1$.…

Metric Geometry · Mathematics 2019-03-12 Panu Lahti

The degree of irrationality of a projective variety $X$ is defined to be the smallest degree rational dominant map to a projective space of the same dimension. For abelian surfaces, Yoshihara computed this invariant in specific cases, while…

Algebraic Geometry · Mathematics 2021-10-27 Nathan Chen

Over the past few decades, there has been extensive research on scattered subspaces, partly because of their link to MRD codes. These subspaces can be characterized using linearized polynomials over finite fields. Within this context,…

Combinatorics · Mathematics 2024-02-26 D. Bartoli , A. Giannoni , G. Marino

Recently, Ghosh \& Haynes \cite{HG} proved a Khintchine-type result for the problem of Diophantine approximation in certain projective spaces. In this note we complement their result by observing that a Jarn\'{\i}k-type result also holds…

Number Theory · Mathematics 2016-05-25 Stephen Harrap , Mumtaz Hussain

In this paper we introduce a new technique to prove the existence of closed subspaces of maximal dimension inside sets of topological vector sequence spaces. The results we prove cover some sequence spaces not studied before in the context…

Functional Analysis · Mathematics 2015-10-06 Geraldo Botelho , Daniel Cariello , Vinícius Fávaro , Daniel Pellegrino

A \emph{subcube partition} is a partition of the Boolean cube $\{0,1\}^n$ into subcubes. A subcube partition is irreducible if the only sub-partitions whose union is a subcube are singletons and the entire partition. A subcube partition is…

An irrational number $\theta$ is called Diophantine if there exist $c>0$ and $\tau < \infty$ such that $\left| \theta - \frac{p}{q} \right| \ge \frac{c}{q^\tau}$ holds for every $(p,q) \in \mathbb{Z} \times \mathbb{N}$. In this paper, we…

Number Theory · Mathematics 2026-03-02 Geraldo César Gonçalves Ferreira , Sávio Ribas

Basic algebraic and combinatorial properties of finite vector spaces in which individual vectors are allowed to have multiplicities larger than $ 1 $ are derived. An application in coding theory is illustrated by showing that multispace…

Information Theory · Computer Science 2024-09-04 Mladen Kovačević

Two-sided conformally recurrent 4-dimensional self-dual spaces are considered. It is shown that such spaces are equipped with nonexpanding congruences of null strings. The general structure of weak nonexpanding hyperheavenly spaces is…

Mathematical Physics · Physics 2020-09-18 Adam Chudecki

The purpose of this article is to study the anti-coproximinal and strongly anti-coproximinal subspaces of the Banach space of all bounded (continuous) functions. We obtain a tractable necessary condition for a subspace to be stronsgly…

Functional Analysis · Mathematics 2026-02-02 Shamim Sohel , Souvik Ghosh , Debmalya Sain , Kallol Paul

A geometrical construction of superconformal transformations in six dimensional (2,0) superspace is proposed. Superconformal Killing vectors are determined. It is shown that the transformation of the tensor multiplet involves a zero…

High Energy Physics - Theory · Physics 2009-10-31 C. Grojean , J. Mourad