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Rene Rühr

Publications and source records attributed to Rene Rühr.

9 recordsLinked to original sources
arXiv2019

Effective counting on translation surfaces

We prove an effective version of a celebrated result of Eskin and Masur: for any affine invariant manifold of translation surfaces, almost every translation surface has quadratic growth for the saddle connection holonomy vectors, with an effective bound of the error. We also provide effective versions of counting in sectors and in ellipses.

math.DS↗
arXiv2019

Effective counting for discrete lattice orbits in the plane via Eisenstein series

We prove effective bounds on the rate in the quadratic growth asymptotics for the orbit of a non-uniform lattice of SL(2,R), acting linearly on the plane. This gives an error bound in the count of saddle connection holonomies, for some Veech surfaces. The proof uses Eisenstein series and relies on earlier work of many authors (notably Selberg). Our results improve earlier error bounds for counting in sectors and in smooth star shaped domains.

math.DS↗
arXiv2019

Metric Diophantine approximation with congruence conditions

We prove a version of the Khinchine--Groshev theorem for Diophantine approximation of matrices subject to a congruence condition. The proof relies on an extension of the Dani correspondence to the quotient by a congruence subgroup. This correspondence together with a multiple ergodic theorem are used to study rational approximations in several congruence classes simultaneously. The result in this part holds in the generality of weighted approximation but is restricted to simple approximation functions.

math.NT↗
arXiv2018

Counting saddle connections in a homology class modulo $q$

We give effective estimates for the number of saddle connections on a translation surface that have length $\leq L$ and are in a prescribed homology class modulo $q$. Our estimates apply to almost all translation surfaces in a stratum of the moduli space of translation surfaces, with respect to the Masur-Veech measure on the stratum.

math.DS↗
arXiv2016

Distribution of Shapes of orthogonal Lattices

It was recently shown by Aka, Einsiedler and Shapira that if d>2, the set of primitive vectors on large spheres when projected to the d-1-dimensional sphere coupled with the shape of the lattice in their orthogonal complement equidistribute in the product space of the sphere with the space of shapes of d-1-dimensional lattices. Specifically, for d=3,4,5 some congruence conditions are assumed. By using recent advances in the theory of unipotent flows, we effectivize the dynamical proof to remove those conditions for d=4,5. It also follows that equidistribution takes place with a polynomial error term with respect to the length of the primitive points.

math.DS↗
arXiv2016

A badly expanding set on the $2$-torus

We give a counterexample to a conjecture stated in Linial and London 2006 regarding expansion on $\mathbb{T}^2$ under $\begin{bmatrix}1&1\\ 0&1\end{bmatrix}$ and $\begin{bmatrix}1&0\\ 1&1\end{bmatrix}$.

math.CO↗
arXiv2014

Effectivity of Uniqueness of the Maximal Entropy Measure on $p$-adic homogeneous spaces

We consider the dynamical system given by a diagonalizable element $a$ of a closed linear unimodular algebraic subgroup $G$ of the special linear group over the $p$-adic numbers acting by translation on a finite volume quotient $X$. Assuming that this action is exponentially mixing (e.g.\ if $G$ is simple) we give an effective version (in terms of $K$-finite vectors of the regular representation) of the following statement: If $μ$ is an $a$-invariant probability measure with measure-theoretical entropy close to the topological entropy of $a$ then $μ$ is close to the unique $G$-invariant probability measure of $X$.

math.DS↗