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We show that all countable subsets of any pseudocompact quasitopological group in the form of a Korovin orbit are closed, discrete, and $C^\ast$-embedded. Consequently, any infinite pseudocompact Korovin orbit is not homeomorphic to a…

General Topology · Mathematics 2023-08-22 Evgenii Reznichenko , Mikhail Tkachenko

We consider groups of orientation-preserving real analytic diffeomorphisms of the circle which have a finite image under the rotation number function. We show that if such a group is nondiscrete with respect to the $C^1$-topology then it…

Dynamical Systems · Mathematics 2008-11-04 Yoshifumi Matsuda

The tangled closure of a collection of subsets of a topological space is the largest subset in which each member of the collection is dense. This operation models a logical `tangle modality' connective, of significance in finite model…

Logic · Mathematics 2018-11-08 Robert Goldblatt , Ian Hodkinson

We prove that the orbit closure of the determinant is not normal. A similar result is obtained for the orbit closure of the permanent multiplied by a power of a linear form.

Algebraic Geometry · Mathematics 2010-07-13 Shrawan Kumar

We investigate the rotation sets of open billiards in $\mathbb{R}^N$ for the natural observable related to a starting point of a given billiard trajectory. We prove that the general rotation set is convex and the set of all convex…

Dynamical Systems · Mathematics 2015-06-01 Zainab Alsheekhhussain

We study the Zariski closure of points in local deformation rings corresponding to potential semi-stable representations with certain prescribed $p$-adic Hodge theoretic properties. We show in favourable cases that the closure is equal to a…

Number Theory · Mathematics 2020-02-24 Matthew Emerton , Vytautas Paskunas

In this paper we first note a result of birational automorphisms with bounded degree of projective varieties related with the Zariski dense orbit conjecture (ZDO) and the Zariski density of periodic points. Next, we give a reduced result of…

Algebraic Geometry · Mathematics 2023-12-22 Sichen Li

We prove the Zariski dense orbit conjecture in positive characteristic for endomorphisms of $\mathbb{G}_a^N$ defined over $\overline{\mathbb{F}_p}$.

Number Theory · Mathematics 2022-03-01 Dragos Ghioca , Sina Saleh

We establish an analogue of Ratner's orbit closure theorem for any connected closed subgroup generated by unipotent elements in $\operatorname{SO}(d,1)$ acting on the space $\Gamma\backslash \operatorname{SO}(d,1)$, assuming that the…

Dynamical Systems · Mathematics 2024-12-04 Minju Lee , Hee Oh

We investigate the question of whether or not the orbit of a point in A/Q, under the natural action of a subset S of Q, is dense in A/Q. We prove that if the set S is a multiplicative semigroup which contains at least two multiplicatively…

Number Theory · Mathematics 2013-03-08 Alan Haynes , Sara Munday

In this paper we prove the following theorem. Let $f$ be a dominant endomorphism of a smooth projective surface over an algebraically closed field of characteristic $0$. If there is no nonconstant invariant rational function under $f$, then…

Dynamical Systems · Mathematics 2021-04-06 Junyi Xie

We give a short discussion about a weaker form of minimality (called quasi-minimality). We call a system quasi-minimal if all dense orbits form an open set. It is hard to find examples which are not already minimal. Since elliptic behaviour…

Dynamical Systems · Mathematics 2019-06-10 Christian Pries

Let $(X,d,T )$ be a topological dynamical system with the specification property. We consider the non-dense orbit set $E(z_0)$ and show that for any non-transitive point $z_0\in X$, this set $E(z_0)$ is empty or carries full topological…

Dynamical Systems · Mathematics 2024-10-10 Cao Zhao , Jiao Yang , Xiaoyao Zhou

Let $G$ be a real, reductive algebraic group, and let $X$ be a homogeneous space for $G$ with a non-zero invariant density. We give an explicit description of a Zariski open, dense subset of the asymptotics of the tempered support of…

Representation Theory · Mathematics 2017-04-04 Benjamin Harris , Tobias Weich

Let $S$ be a closed surface of genus $g\geq 1$, furnished with an area form $\omega$. We show that there exists an open and dense set ${\mathcal O_r}$ of the space of Hamiltonian diffeomorphisms of class $C^r$, $1\leq r\leq\infty$, endowed…

Dynamical Systems · Mathematics 2023-06-07 Patrice Le Calvez , Martin Sambarino

We give necessary and sufficient conditions for a linear reflection group in the sense of Vinberg to be Zariski-dense in the ambient projective general linear group. As an application, we show that every irreducible right-angled Coxeter…

Geometric Topology · Mathematics 2025-04-03 Jacques Audibert , Sami Douba , Gye-Seon Lee , Ludovic Marquis

We study in this paper the jet schemes of the closure of nilpotent orbits in a finite-dimensional complex reductive Lie algebra. For the nilpotent cone, which is the closure of the regular nilpotent orbit, all the jet schemes are…

Representation Theory · Mathematics 2016-02-17 Anne Moreau , Rupert W. T. Yu

We construct a continuum of non-homeomorphic compact subspaces of the real line R without singleton components. Thus from the purely topological point of view the real line contains not only more closed sets than open sets but also more…

General Topology · Mathematics 2020-04-24 Gerald Kuba

We investigate for which linear-algebraic groups (over the complex numbers or any local field) there exists subgroups which are dense in the Zariski topology, but discrete in the Hausdorff topology. For instance, such subgroups exist for…

alg-geom · Mathematics 2008-02-03 J. Winkelmann

We show that any nonzero orbit under a noncompact, simple, irreducible linear group is dense in the Bohr compactification of the ambient space.

Dynamical Systems · Mathematics 2019-02-20 Roger Howe , Francois Ziegler