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A symplectic structure on the space of nondegenerate and nonparametrized curves in a locally affine manifold is defined. We also consider several interesting spaces of nondegenerate projective curves endowed with Poisson structures. This…

High Energy Physics - Theory · Physics 2009-10-28 L. Guieu , V. Yu. Ovsienko

The notions of nonpositive curved spaces and biautomatic groups are generalizations of the geometric properties of hyperbolic spaces and computational properties of their fundamental groups. Given the mutual origins of these conditions, one…

Group Theory · Mathematics 2011-11-15 Rena M. H. Levitt

We prove autoduality for curves of compact type and, more generally, treelike curves with planar singularities. More precisely, we produce an isomorphism between the generalized Jacobian of such a curve and the connected component of the…

Algebraic Geometry · Mathematics 2012-08-08 Eduardo Esteves , Flávio Rocha

We give a geometric characterisation of those groups that arise as fixed subgroups of finite-order untwisted automorphisms of right-angled Artin groups (RAAGs). They are precisely the fundamental groups of a class of compact special cube…

Group Theory · Mathematics 2026-03-25 Elia Fioravanti

A topological space is almost locally compact if it contains a dense locally compact subspace. We generalize a result from \cite{Ma}, showing that isomorphism on Borel classes of almost locally compact Polish metric structures is always…

Logic · Mathematics 2025-08-12 Maciej Malicki

We give explicit necessary and sufficient conditions for the abstract commensurability of certain families of 1-ended, hyperbolic groups, namely right-angled Coxeter groups defined by generalized theta-graphs and cycles of generalized…

Group Theory · Mathematics 2017-10-06 Pallavi Dani , Emily Stark , Anne Thomas

We establish a structure theorem for the connected automorphism groups of smooth complete toroidal horospherical varieties, that is, toric fibrations over rational homogeneous spaces. The key ingredient is a characterization of the Demazure…

Algebraic Geometry · Mathematics 2026-03-10 Lorenzo Barban , DongSeon Hwang , Minseong Kwon

We first characterize the automorphism groups of Hodge structures of cubic threefolds and cubic fourfolds. Then we determine for some complex projective manifolds of small dimension (cubic surfaces, cubic threefolds, and non-hyperelliptic…

Algebraic Geometry · Mathematics 2023-06-22 Zhiwei Zheng

We adapt a proof of Lascar in order to show the simplicity of the group of automorphisms fixing pointwise all non-generic elements for a class of uncountable models of suitable theories, encompassing both strongly minimal theories as well…

We first give a relative flexible process to construct torsion cohomology classes for Shimura varieties of Kottwitz-Harris-Taylor type with coefficient in a non too regular local system. We then prove that associated to each torsion…

Number Theory · Mathematics 2017-01-03 Pascal Boyer

Let G be a countable group. We proof that there is a model companion for the approximate theory of a Hilbert space with a group G of automorphisms. We show that G is amenable if and only if the structure induced by countable copies of the…

Logic · Mathematics 2007-05-23 Alexander Berenstein

We establish some geometric constraints on compact Coxeter polytopes in hyperbolic spaces and show that these constraints can be a very useful tool for the classification problem of reflective anisotropic Lorentzian lattices and cocompact…

Geometric Topology · Mathematics 2022-03-10 Nikolay Bogachev

We show that any adjoint absolutely simple linear algebraic group over a field of characteristic zero is the automorphism group of some projector on a central simple algebra. Projective homogeneous varieties can be described in these terms;…

Group Theory · Mathematics 2020-04-20 Viktor Petrov , Andrei Semenov

We provide a complete description of the automorphism group $\Aut (W)$ of a Coxeter group $W$ admitting a star-shaped finite Coxeter diagram. We prove that each automorphism decomposes as a product of inner and diagram automorphisms, along…

Group Theory · Mathematics 2026-05-22 Arijit Mahato , Tushar Kanta Naik , A Rameswar Patro

We study domains in complex $n$-space with automorphism group that does not depend on the full $n$ dimensions of the ambient space. A sufficient geometric condition is obtained to guarantee that a domain has such a "thin" automorphism…

Complex Variables · Mathematics 2008-10-28 Jisoo Byun , Steven G. Krantz

In this paper we prove that a pure, regular, totally odd, polarizable weakly compatible system of $l$-adic representations is potentially automorphic. The innovation is that we make no irreducibility assumption, but we make a purity…

Number Theory · Mathematics 2019-02-20 Stefan Patrikis , Richard Taylor

Using elementary graded automorphisms of polytopal algebras (essentially the coordinate rings of projective toric varieties) polyhedral versions of the group of elementary matrices and the Steinberg and Milnor groups are defined. They…

K-Theory and Homology · Mathematics 2007-05-23 Winfried Bruns , Joseph Gubeladze

Self equivalences of classifying spaces of $p$-local compact groups are well understood by means of the algebraic structure that gives rise to them, but explicit descriptions are lacking. In this paper we use a construction of Robinson of…

Algebraic Topology · Mathematics 2015-07-20 Alex Gonzalez , Ran Levi

A classification of homogeneous compact Tits geometries of irreducible spherical type, with connected panels and admitting a compact flag-transitive automorphism group acting continuously on the geometry, has been obtained by Kramer and…

Geometric Topology · Mathematics 2019-10-09 Antonio Pasini

We show the existence of generalized clusters of a finite or even infinite number of sets, with minimal total perimeter and given total masses, in metric measure spaces homogeneous with respect to a group acting by measure preserving…

Analysis of PDEs · Mathematics 2021-12-16 Matteo Novaga , Emanuele Paolini , Eugene Stepanov , Vincenzo Maria Tortorelli