Zobrazeno 1 - 10
of 376
pro vyhledávání: '"Douba, A."'
In this paper, a new classification model based on covariance matrices is built in order to classify buried objects. The inputs of the proposed models are the hyperbola thumbnails obtained with a classical Ground Penetrating Radar (GPR) system. These
Externí odkaz:
http://arxiv.org/abs/2410.07117
Autor:
Douba, Sami, Huang, Junzhi
We show that for each $n \geq 2$, the systoles of closed hyperbolic $n$-manifolds form a dense subset of $(0, +\infty)$. We also show that for any $n\geq 2$ and any Salem number $\lambda$, there is a closed arithmetic hyperbolic $n$-manifold of systo
Externí odkaz:
http://arxiv.org/abs/2404.15927
Autor:
Douba, Sami
We exhibit closed hyperbolic manifolds with arbitrarily small systole in each dimension that are not quasi-arithmetic in the sense of Vinberg, and are thus not commensurable to those constructed by Agol, Belolipetsky--Thomson, and Bergeron--Haglund--
Externí odkaz:
http://arxiv.org/abs/2309.16051
We prove that certain families of compact Coxeter polyhedra in 4- and 5-dimensional hyperbolic space constructed by Makarov give rise to infinitely many commensurability classes of reflection groups in these dimensions.
Comment: Final version, t
Comment: Final version, t
Externí odkaz:
http://arxiv.org/abs/2309.07691
We prove that any hyperbolic group acting properly discontinuously and cocompactly on a $\mathrm{CAT}(0)$ cube complex admits a projective Anosov representation into $\mathrm{SL}(d, \mathbb{R})$ for some $d$. More specifically, we show that if $\Gamm
Externí odkaz:
http://arxiv.org/abs/2309.03695
Autor:
Douba, Sami, Tsouvalas, Konstantinos
Motivated by a question of M. Kapovich, we show that the $\mathbb{Z}^2$ subgroups of $\mathsf{SL}_3(\mathbb{R})$ that are regular in the language of Kapovich--Leeb--Porti, or divergent in the sense of Guichard--Wienhard, are precisely the lattices in
Externí odkaz:
http://arxiv.org/abs/2306.11262
Autor:
Douba, Sami
Motivated by a question of Stover, we discuss an example of a Zariski-dense finitely generated subgroup of $\mathrm{SL}_5(\mathbb{Z})$ that is not finitely presented.
Comment: 4 pages, 1 figure
Comment: 4 pages, 1 figure
Externí odkaz:
http://arxiv.org/abs/2304.12638
Autor:
Bogachev, Nikolay, Douba, Sami
The L\"obell polyhedra form an infinite family of compact right-angled hyperbolic polyhedra in dimension $3$. We observe, through both elementary and more conceptual means, that the ``systoles'' of the L\"obell polyhedra approach $0$, so that these p
Externí odkaz:
http://arxiv.org/abs/2304.12590
Autor:
Douba, Sami, Tsouvalas, Konstantinos
We exhibit Anosov subgroups of $\mathsf{SL}_d(\mathbb{R})$ that do not embed discretely in any rank-$1$ simple Lie group of noncompact type, or indeed, in any finite product of such Lie groups. These subgroups are isomorphic to free products $\Gamma
Externí odkaz:
http://arxiv.org/abs/2210.17549
Autor:
Douba, Sami
For each integer $n \geq 3$, we exhibit a nonuniform arithmetic lattice in $\mathrm{SO}(n,1)$ containing Zariski-dense surface subgroups.
Comment: Typos in the proofs of Lemma 2 and Theorem 1 were corrected, and a remark was appended to account
Comment: Typos in the proofs of Lemma 2 and Theorem 1 were corrected, and a remark was appended to account
Externí odkaz:
http://arxiv.org/abs/2207.04255