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Related papers: The Extended Exterior Sphere Condition

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We provide a novel analytical proof of an improved version of [10, Theorem 3.1], showing that the complement of a closed set satisfying the extended exterior sphere condition is nothing but the union of closed balls with lower…

Metric Geometry · Mathematics 2025-04-01 Chadi Nour , Jean Takche

We introduce a variable radius form of the extended exterior sphere condition of [16], and then, we prove that the complement of a closed set satisfying this new property is nothing but the union of closed balls with lower semicontinous…

Metric Geometry · Mathematics 2025-01-22 Chadi Nour , Jean Takche

Parallel to the main results of [13] and [14], which explore the equivalence between prox-regularity, the exterior sphere condition, and $S$-convexity, we present novel characterizations of the $r$-strong convexity property, namely, of the…

Metric Geometry · Mathematics 2025-01-15 Chadi Nour , Jean Takche

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

We present several new characterizations of the spherically supported geometric property introduced in [19], emphasizing its connection with the exterior sphere condition with infinite radius. Moreover, we strengthen and provide a more…

Metric Geometry · Mathematics 2025-12-18 Chadi Nour

We point out that any stable generalized complex structure on a sphere bundle over a closed surface of genus at least two must be of constant type.

Differential Geometry · Mathematics 2025-01-17 Rafael Torres

In this article a class of closed convex sets in the Euclidean $n$-space which are the convex hull of their profiles is described. Thus a generalization of Krein-Milman theorem\cite{Lay:1982} to a class of closed non-compact convex sets is…

Metric Geometry · Mathematics 2013-01-07 M. Beltagy , S. Shenawy

We present a necessary and sufficient condition for the reachable set, i.e., the set of states reachable from a ball of initial states at some time, of an ordinary differential equation to be convex. In particular, convexity is guaranteed…

Optimization and Control · Mathematics 2013-03-01 Gunther Reißig

We prove that an equivalent condition for a uniform space to be coverable is that the images of the natural projections in the fundamental inverse system are uniformly open in a certain sense. As corollaries we (1) obtain a concrete way to…

General Topology · Mathematics 2007-10-11 Conrad Plaut

Throughout, let $R$ be a commutative Noetherian ring. A ring $R$ satisfies Serre's condition $(S_{\ell})$ if for all $P \in \Spec R,$ $\depth R_P \geq \min \{ \ell , \dim R_P \}$. Serre's condition has been a topic of expanding interest. In…

Commutative Algebra · Mathematics 2018-10-11 Brent Holmes

The aim of this note is to present an alternative proof for an already known result relative to the solvability of the Dirichlet problem in Riemannian manifolds (see remark 0.1). In particular, we discuss the p-regularity (regularity…

Analysis of PDEs · Mathematics 2015-04-10 Daniele Valtorta

We generalize Jacod's condition and introduce a new type sufficient condition for the uniform integrability of the general stochastic exponential.

Probability · Mathematics 2020-01-01 Besik Chikvinidze

In this paper, our aim is to obtain a new generalization of the well-kown Rhoades' contractive condition. To do this, we introduce the notion of an $S$-normed space. We extend the Rhoades' contractive condition to $S$-normed spaces and…

General Mathematics · Mathematics 2021-05-28 Nihal TaŞ , Nihal Özgür

A sufficient condition of the convergence of an exotic formal series (a kind of power series with complex exponents) solution to an ODE of a general form is proposed.

Classical Analysis and ODEs · Mathematics 2019-01-01 Renat Gontsov , Irina Goryuchkina

We study the general properties of fluid spheres satisfying the heuristic assumption that their areas and proper radius are equal (the Euclidean condition). Dissipative and non-dissipative models are considered. In the latter case, all…

General Relativity and Quantum Cosmology · Physics 2014-11-20 L. Herrera , N. O. Santos

We treat the circular and elliptic restricted three-body problems in inertial frames as periodically forced Kepler problems with additional singularities and explain that in this setting the main result of [4] is applicable. This guarantees…

Dynamical Systems · Mathematics 2021-02-24 Rafael Ortega , Lei Zhao

High proved the following theorem. If the intersections of any two congruent copies of a plane convex body are centrally symmetric, then this body is a circle. In our paper we extend the theorem of High to spherical, Euclidean and…

Metric Geometry · Mathematics 2018-07-05 J. Jerónimo-Castro , E. Makai,

We study existence of random elements with partially specified distributions. The technique relies on the existence of a positive extension for linear functionals accompanied by additional conditions that ensure the regularity of the…

Probability · Mathematics 2015-01-20 Raphael Lachieze-Rey , Ilya Molchanov

In this paper, we give spectral conditions to guarantee the existence of two edge disjoint cycles and two cycles of the same length. These two results can be seen as spectral analogues of Erd\H{o}s and Posa's size condition and Erd\H{o}s'…

Combinatorics · Mathematics 2021-08-23 Huiqiu Lin , Mingqing Zhai , Yanhua Zhao

The Spectral Excess Theorem (SPET) for distance-regular graphs states that a regular (connected) graph is distance-regular if and only if its spectral-excess equals its average excess. Recently, some local or global approaches to the SPET…

Spectral Theory · Mathematics 2012-05-29 M. A. Fiol
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