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We produce a short and elementary algorithm to compute an upper bound for the canonical dimension of a spit semisimple linear algebraic group. Using this algorithm we confirm previously known bounds by Karpenko and Devyatov as well as we…

Algebraic Geometry · Mathematics 2021-08-19 Kirill Zainoulline

We study sets of solutions to equations over a free group, projections of such sets, and the structure of elementary sets defined over a free group. The structre theory we obtain enable us to answer some questions of A. Tarski's, and…

Group Theory · Mathematics 2007-05-23 Zlil Sela

In this paper we develop the formalism of rational complex Bezier curves. This framework is a simple extension of the CAD paradigm, since it describes arc of curves in terms of control polygons and weights, which are extended to complex…

Numerical Analysis · Mathematics 2025-12-10 A. Canton , L. Fernandez-Jambrina , M. J. Vazquez-Gallo

We find a natural $L_{\omega_1,\omega}$-axiomatisation $\Sigma$ of a structure on the upper half-plane $\mathbb{H}$ as the covering space of modular curves. The main theorem states that $\Sigma$ has a unique model in every uncountable…

Logic · Mathematics 2022-11-29 Boris Zilber , Chris Daw

We explore the canonical Grothendieck topology in some specific circumstances. First we use a description of the canonical topology to get a variant of Giraud's Theorem. Then we explore the canonical Grothendieck topology on the categories…

Algebraic Topology · Mathematics 2019-09-10 Cynthia Lester

We provide sufficient conditions for two subgroups of a hierarchically hyperbolic group to generate an amalgamated free product over their intersection. The result applies in particular to certain geometric subgroups of mapping class groups…

Group Theory · Mathematics 2026-01-07 Giorgio Mangioni

We use the mathematical structure of group algebras and $H^{+}$-algebras for describing certain problems concerning the quantum dynamics of systems of angular momenta, including also the spin systems. The underlying groups are ${\rm SU}(2)$…

Mathematical Physics · Physics 2011-02-22 J. J. Sławianowski , V. Kovalchuk , A. Martens , B. Gołubowska , E. E. Rożko

We study differential forms on an algebraic compactification of a moduli space of metric graphs. Canonical examples of such forms are obtained by pulling back invariant differentials along a tropical Torelli map. The invariant differential…

Algebraic Geometry · Mathematics 2021-11-24 Francis Brown

Rational points in the boundary of a hyperbolic curve over a field with sufficiently nontrivial Kummer theory are the source for an abundance of sections of the fundamental group exact sequence. We follow and refine Nakamura's approach…

Algebraic Geometry · Mathematics 2008-09-02 Jakob Stix

We describe a family of new algorithms for finding the canonical image of a set of points under the action of a permutation group. This family of algorithms makes use of the orbit structure of the group, and a chain of subgroups of the…

Group Theory · Mathematics 2017-12-05 Christopher Jefferson , Eliza Jonauskyte , Markus Pfeiffer , Rebecca Waldecker

Results on matrix canonical forms are used to give a complete description of the higher rank numerical range of matrices arising from the study of quantum error correction. It is shown that the set can be obtained as the intersection of…

Functional Analysis · Mathematics 2011-02-10 Chi-Kwong Li , Nung-Sing Sze

We introduce a quantization of the graded algebra of functions on the canonical cone of an algebraic curve C, based on the theory of formal pseudodifferential operators. When C is a complex curve with Poincar\'e uniformization, we propose…

Algebraic Geometry · Mathematics 2024-04-04 B. Enriquez , A. Odesskii

This paper investigates the representation-theoretic structure of the Koszul cohomology of a smooth projective variety $X$ over an algebraically closed field $k$, admitting an action of a finite group $G$ of order coprime to ${\rm…

Algebraic Geometry · Mathematics 2026-02-19 Kostas Karagiannis , Aristides Kontogeorgis , Konstantia Manousou Sotiropoulou

We study new families of curves that are suitable for efficiently parametrizing their moduli spaces. We explicitly construct such families for smooth plane quartics in order to determine unique representatives for the isomorphism classes of…

Algebraic Geometry · Mathematics 2019-02-06 Reynald Lercier , Christophe Ritzenthaler , Florent Rovetta , Jeroen Sijsling

The notion of formal Siegel modular forms for an arithmetic subgroup $\Gamma$ of the symplectic group of genus $n$ is a generalization of symmetric formal Fourier-Jacobi series. Assuming an upper bound on the affine covering number of the…

Number Theory · Mathematics 2024-07-09 Jan Hendrik Bruinier , Martin Raum

We show how the theory of canonical bases in modified universal enveloping algebras can be used to develop the theory of Chevalley groups over any commutative ring with 1.

Representation Theory · Mathematics 2007-09-11 G. Lusztig

A generalization of classical gauge theory is presented, in the framework of a noncommutative-geometric formalism of quantum principal bundles over smooth manifolds. Quantum counterparts of classical gauge bundles, and classical gauge…

q-alg · Mathematics 2008-11-26 Mico Durdevic

Let S be a finite graph and G be the corresponding free partially commutative group. In this paper we study subgroups generated by vertices of the graph S, which we call canonical parabolic subgroups. A natural extension of the definition…

Group Theory · Mathematics 2007-05-23 A. J. Duncan , I. V. Kazachkov , V. N. Remeslennikov

Given a smooth curve, the canonical representation of its automorphism group is the space of global holomorphic differential 1-forms as a representation of the automorphism group of the curve. In this paper, we study an explicit set of…

Algebraic Geometry · Mathematics 2013-02-07 Ruthi Hortsch

In the paper is we generalize known descriptions of rings of semi-invariants for regular modules over Euclidean and canonical algebras to arbitrary concealed-canonical algebras.

Representation Theory · Mathematics 2012-12-18 Grzegorz Bobinski