scholarly journals Automorphism group of the moduli space of parabolic bundles over a curve

2021 ◽  
Vol 393 ◽  
pp. 108070
Author(s):  
David Alfaya ◽  
Tomás L. Gómez
Keyword(s):  
Automorphism Group ◽  
Moduli Space ◽  
Parabolic Bundles

scholarly journals Non-singular plane curves with an element of “large” order in its automorphism group

2016 ◽  
Vol 26 (02) ◽  
pp. 399-433 ◽  
Author(s):  
Eslam Badr ◽  
Francesc Bars
Keyword(s):  
Automorphism Group ◽  
Moduli Space ◽  
Plane Curves ◽  
Closed Field ◽  
Fixed Degree ◽  
Plane Model ◽  
Zero Characteristic ◽  
Large Order ◽  
Nontrivial Group ◽  
Genus Formula

Let [Formula: see text] be the moduli space of smooth, genus [Formula: see text] curves over an algebraically closed field [Formula: see text] of zero characteristic. Denote by [Formula: see text] the subset of [Formula: see text] of curves [Formula: see text] such that [Formula: see text] (as a finite nontrivial group) is isomorphic to a subgroup of [Formula: see text] and let [Formula: see text] be the subset of curves [Formula: see text] such that [Formula: see text], where [Formula: see text] is the full automorphism group of [Formula: see text]. Now, for an integer [Formula: see text], let [Formula: see text] be the subset of [Formula: see text] representing smooth, genus [Formula: see text] curves that admit a non-singular plane model of degree [Formula: see text] (in this case, [Formula: see text]) and consider the sets [Formula: see text] and [Formula: see text]. In this paper we first determine, for an arbitrary but a fixed degree [Formula: see text], an algorithm to list the possible values [Formula: see text] for which [Formula: see text] is non-empty, where [Formula: see text] denotes the cyclic group of order [Formula: see text]. In particular, we prove that [Formula: see text] should divide one of the integers: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] or [Formula: see text]. Secondly, consider a curve [Formula: see text] with [Formula: see text] such that [Formula: see text] has an element of “very large” order, in the sense that this element is of order [Formula: see text], [Formula: see text], [Formula: see text] or [Formula: see text]. Then we investigate the groups [Formula: see text] for which [Formula: see text] and also we determine the locus [Formula: see text] in these situations. Moreover, we work with the same question when [Formula: see text] has an element of “large” order: [Formula: see text], [Formula: see text] or [Formula: see text] with [Formula: see text] an integer.

scholarly journals On Automorphisms of Moduli Spaces of Parabolic Vector Bundles

2019 ◽  
Author(s):  
Carolina Araujo ◽  
Thiago Fassarella ◽  
Inder Kaur ◽  
Alex Massarenti
Keyword(s):  
Automorphism Group ◽  
Moduli Space ◽  
Moduli Spaces ◽  
Vector Bundles ◽  
Automorphism Groups ◽  
Weight Vector ◽  
Fano Variety ◽  
Real Numbers ◽  
Isolated Singularities

AbstractFix $n\geq 5$ general points $p_1, \dots , p_n\in{\mathbb{P}}^1$ and a weight vector ${\mathcal{A}} = (a_{1}, \dots , a_{n})$ of real numbers $0 \leq a_{i} \leq 1$. Consider the moduli space $\mathcal{M}_{{\mathcal{A}}}$ parametrizing rank two parabolic vector bundles with trivial determinant on $\big ({\mathbb{P}}^1, p_1,\dots , p_n\big )$ that are semistable with respect to ${\mathcal{A}}$. Under some conditions on the weights, we determine and give a modular interpretation for the automorphism group of the moduli space $\mathcal{M}_{{\mathcal{A}}}$. It is isomorphic to $\left (\frac{\mathbb{Z}}{2\mathbb{Z}}\right )^{k}$ for some $k\in \{0,\dots , n-1\}$ and is generated by admissible elementary transformations of parabolic vector bundles. The largest of these automorphism groups, with $k=n-1$, occurs for the central weight ${\mathcal{A}}_{F}= \left (\frac{1}{2},\dots ,\frac{1}{2}\right )$. The corresponding moduli space ${\mathcal M}_{{\mathcal{A}}_F}$ is a Fano variety of dimension $n-3$, which is smooth if $n$ is odd, and has isolated singularities if $n$ is even.

scholarly journals THE GENERIC FIBRE OF MODULI SPACES OF BOUNDED LOCAL G-SHTUKAS

2021 ◽  
pp. 1-80
Author(s):  
Urs Hartl ◽  
Eva Viehmann
Keyword(s):  
Automorphism Group ◽  
Moduli Space ◽  
Moduli Spaces ◽  
Function Field ◽  
Period Map ◽  
Generic Fibre ◽  
Divisible Groups

Abstract Moduli spaces of bounded local G-shtukas are a group-theoretic generalisation of the function field analogue of Rapoport and Zink’s moduli spaces of p-divisible groups. In this article we generalise some very prominent concepts in the theory of Rapoport-Zink spaces to our setting. More precisely, we define period spaces, as well as the period map from a moduli space of bounded local G-shtukas to the corresponding period space, and we determine the image of the period map. Furthermore, we define a tower of coverings of the generic fibre of the moduli space, which is equipped with a Hecke action and an action of a suitable automorphism group. Finally, we consider the $\ell $ -adic cohomology of these towers. Les espaces de modules de G-chtoucas locaux bornés sont une généralisation des espaces de modules de groupes p-divisibles de Rapoport-Zink, au cas d’un corps de fonctions local, pour des groupes plus généraux et des copoids pas nécessairement minuscules. Dans cet article nous définissons les espaces de périodes et l’application de périodes associés à un tel espace, et nous calculons son image. Nous étudions la tour au-dessus de la fibre générique de l’espace de modules, équipée d’une action de Hecke ainsi que d’une action d’un groupe d’automorphismes. Enfin, nous définissons la cohomologie $\ell $ -adique de ces tours.

scholarly journals Finite Generation of the Algebra of Type A Conformal Blocks via Birational Geometry

2018 ◽  
Author(s):  
Han-Bom Moon ◽  
Sang-Bum Yoo
Keyword(s):  
Moduli Space ◽  
Type A ◽  
Projective Line ◽  
Birational Geometry ◽  
Finite Generation ◽  
Conformal Blocks ◽  
Parabolic Bundles ◽  
Mori Dream Space ◽  
Birational Model ◽  
Effective Cone

Abstract We study the birational geometry of the moduli space of parabolic bundles over a projective line, in the framework of Mori’s program. We show that the moduli space is a Mori dream space. As a consequence, we obtain the finite generation of the algebra of type A conformal blocks. Furthermore, we compute the H-representation of the effective cone that was previously obtained by Belkale. For each big divisor, the associated birational model is described in terms of moduli space of parabolic bundles.

scholarly journals Hyperelliptic Curves with Extra Involutions

2005 ◽  
Vol 8 ◽  
pp. 102-115 ◽  
Author(s):  
J. Gutierrez ◽  
T. Shaska
Keyword(s):  
Automorphism Group ◽  
Moduli Space ◽  
Hyperelliptic Curves ◽  
Rational Model ◽  
Field Of Moduli ◽  
Field Of Definition

AbstractThe purpose of this paper is to study hyperelliptic curves with extra involutions. The locusLgof such genus-ghyperelliptic curves is ag-dimensional subvariety of the moduli space of hyperelliptic curvesHg. The authors present a birational parameterization ofLgvia dihedral invariants, and show how these invariants can be used to determine the field of moduli of points p ∈ Lg. They conjecture that for p ∈Hgwith |Aut(p)| > 2, the field of moduli is a field of definition, and they prove this conjecture for any point p ∈Lgsuch that the Klein 4-group is embedded in the reduced automorphism group ofp. Further, forg= 3, they show that for every moduli point p ∈H3such that |Aut(p)| > 4, the field of moduli is a field of definition. A rational model of the curve over its field of moduli is provided.

PARABOLIC VECTOR BUNDLES AND HERMITIAN-YANG-MILLS CONNECTIONS OVER A RIEMANN SURFACE

1993 ◽  
Vol 04 (03) ◽  
pp. 467-501 ◽  
Author(s):  
JONATHAN A. PORITZ
Keyword(s):  
Riemann Surface ◽  
Vector Bundle ◽  
Sobolev Space ◽  
Moduli Space ◽  
Vector Bundles ◽  
Weighted Sobolev Space ◽  
Conjugacy Classes ◽  
Stable Bundle ◽  
Yang Mills ◽  
Parabolic Bundles

We study a certain moduli space of irreducible Hermitian-Yang-Mills connections on a unitary vector bundle over a punctured Riemann surface. The connections used have non-trivial holonomy around the punctures lying in fixed conjugacy classes of U (n) and differ from each other by elements of a weighted Sobolev space; these connections give rise to parabolic bundles in the sense of Mehta and Seshadri. We show in fact that the moduli space of stable parabolic bundles can be identified with our moduli space of HYM connections, by proving that every stable bundle admits a unique unitary gauge orbit of Hermitian-Yang-Mills connections.

scholarly journals LOCAL STRUCTURE OF MODULI SPACES

2011 ◽  
Vol 22 (12) ◽  
pp. 1683-1709
Author(s):  
FRANCOIS-XAVIER MACHU
Keyword(s):  
Automorphism Group ◽  
Moduli Space ◽  
Moduli Spaces ◽  
Local Structure ◽  
Slice Theorem ◽  
Meromorphic Connections

We provide a sketch of the GIT construction of the moduli spaces for the three classes of connections: the class of meromorphic connections with fixed divisor of poles D and its subclasses of integrable and integrable logarithmic connections. We use the Luna Slice Theorem to represent the germ of the moduli space as the quotient of the Kuranishi space by the automorphism group of the central fiber. This method is used to determine the singularities of the moduli space of connections in some examples.

scholarly journals Integrable Systems and Torelli Theorems for the Moduli Spaces of Parabolic Bundles and Parabolic Higgs Bundles

2016 ◽  
Vol 68 (3) ◽  
pp. 504-520
Author(s):  
Indranil Biswas ◽  
Tomás L. Gómez ◽  
Marina Logares
Keyword(s):  
Moduli Space ◽  
Moduli Spaces ◽  
Integrable Systems ◽  
Algebraic Curve ◽  
Higgs Bundles ◽  
Parabolic Bundles ◽  
Smooth Complex ◽  
Torelli Theorem ◽  
Complex Projective

AbstractWe prove a Torelli theorem for the moduli space of semistable parabolic Higgs bundles over a smooth complex projective algebraic curve under the assumption that the parabolic weight systemis generic. When the genus is at least two, using this result we also prove a Torelli theoremfor the moduli space of semistable parabolic bundles of rank at least two with generic parabolic weights. The key input in the proofs is a method of J.C. Hurtubise.

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