scholarly journals Factorization of Generalized Theta Functions Revisited

2017 ◽  
Vol 24 (01) ◽  
pp. 1-52
Author(s):  
Xiaotao Sun
Keyword(s):  
Line Bundle ◽  
Moduli Space ◽  
Moduli Spaces ◽  
Theta Functions ◽  
Vanishing Theorems ◽  
Smooth Curves ◽  
Canonical Line Bundle

This survey is based on my lectures given in the last few years. As a reference, constructions of moduli spaces of parabolic sheaves and generalized parabolic sheaves are provided. By a refinement of the proof of vanishing theorems, we show, without using vanishing theorems, a new observation that [Formula: see text] is independent of all of the choices for any smooth curves. The estimate of various codimensions and computation of canonical line bundle of moduli space of generalized parabolic sheaves on a reducible curve are provided in Section 6, which is completely new.

scholarly journals CHEN–RUAN COHOMOLOGY OF SOME MODULI SPACES, II

2010 ◽  
Vol 21 (04) ◽  
pp. 497-522 ◽  
Author(s):  
INDRANIL BISWAS ◽  
MAINAK PODDAR
Keyword(s):  
Riemann Surface ◽  
Line Bundle ◽  
Prime Number ◽  
Moduli Space ◽  
Moduli Spaces ◽  
Vector Bundles ◽  
Line Bundles ◽  
Holomorphic Line Bundle ◽  
Stable Vector Bundles

Let X be a compact connected Riemann surface of genus at least two. Let r be a prime number and ξ → X a holomorphic line bundle such that r is not a divisor of degree ξ. Let [Formula: see text] denote the moduli space of stable vector bundles over X of rank r and determinant ξ. By Γ we will denote the group of line bundles L over X such that L⊗r is trivial. This group Γ acts on [Formula: see text] by the rule (E, L) ↦ E ⊗ L. We compute the Chen–Ruan cohomology of the corresponding orbifold.

scholarly journals SPIN VERLINDE SPACES AND PRYM THETA FUNCTIONS

1999 ◽  
Vol 78 (1) ◽  
pp. 52-76 ◽  
Author(s):  
W. M. OXBURY
Keyword(s):  
Line Bundle ◽  
Moduli Space ◽  
Algebraic Curve ◽  
Theta Functions ◽  
Prym Varieties ◽  
Theta Characteristics

It is shown that the theta functions of level $n$ on the principally polarised Prym varieties of an algebraic curve are dual to the sections of the orthogonal theta line bundle on the moduli space of Spin($n$)-bundles over the curve. As a by-product of our computations, we also note that when $n$ is odd, the Pfaffian line bundle on moduli space has a basis of sections labelled by the even theta characteristics of the curve.

scholarly journals AFFINE GEOMETRY OF STRATA OF DIFFERENTIALS

2017 ◽  
Vol 18 (06) ◽  
pp. 1331-1340 ◽  
Author(s):  
Dawei Chen
Keyword(s):  
Line Bundle ◽  
Algebraic Curve ◽  
Invariant Manifolds ◽  
Affine Variety ◽  
Affine Invariant ◽  
Algebraic Varieties ◽  
Hurwitz Spaces ◽  
Smooth Curves ◽  
Canonical Line Bundle ◽  
Teichmuller Dynamics

Affine varieties among all algebraic varieties have simple structures. For example, an affine variety does not contain any complete algebraic curve. In this paper, we study affine-related properties of strata of $k$ -differentials on smooth curves which parameterize sections of the $k$ th power of the canonical line bundle with prescribed orders of zeros and poles. We show that if there is a prescribed pole of order at least $k$ , then the corresponding stratum does not contain any complete curve. Moreover, we explore the amusing question whether affine invariant manifolds arising from Teichmüller dynamics are affine varieties, and confirm the answer for Teichmüller curves, Hurwitz spaces of torus coverings, hyperelliptic strata as well as some low genus strata.

scholarly journals On moduli spaces of Hitchin pairs

2011 ◽  
Vol 151 (3) ◽  
pp. 441-457 ◽  
Author(s):  
INDRANIL BISWAS ◽  
PETER B. GOTHEN ◽  
MARINA LOGARES
Keyword(s):  
Riemann Surface ◽  
Line Bundle ◽  
Moduli Space ◽  
Moduli Spaces ◽  
Isomorphism Class ◽  
Compact Riemann Surface ◽  
List Type ◽  
Holomorphic Line Bundle ◽  
Type Number ◽  
Additional Hypothesis

AbstractLetXbe a compact Riemann surfaceXof genus at–least two. Fix a holomorphic line bundleLoverX. Letbe the moduli space of Hitchin pairs (E, φ ∈H0(End0(E) ⊗L)) overXof rankrand fixed determinant of degreed. The following conditions are imposed:(i)deg(L) ≥ 2g−2,r≥ 2, andL⊗rKX⊗r;(ii)(r, d) = 1; and(iii)ifg= 2 thenr≥ 6, and ifg= 3 thenr≥ 4.We prove that that the isomorphism class of the varietyuniquely determines the isomorphism class of the Riemann surfaceX. Moreover, our analysis shows thatis irreducible (this result holds without the additional hypothesis on the rank for low genus).

scholarly journals Moduli spaces of the stable vector bundles over abelian surfaces

1980 ◽  
Vol 77 ◽  
pp. 47-60 ◽  
Author(s):  
Hiroshi Umemura
Keyword(s):  
Line Bundle ◽  
Moduli Space ◽  
Moduli Spaces ◽  
Vector Bundles ◽  
Ample Line Bundle ◽  
Abelian Surfaces ◽  
Singular Variety ◽  
Stable Bundles ◽  
Stable Vector Bundles ◽  
Closed Subvariety

Let X be a projective non-singular variety and H an ample line bundle on X. The moduli space of H-stable vector bundles exists by Maruyama [4]. If X is a curve defined over C, the structure of the moduli space (or its compactification) M(X, d, r) of stable vector bundles of degree d and rank r on X is studied in detail. It is known that the variety M(X, d, r) is irreducible. Let L be a line bundle of degree d and let M(X, L, r) denote the closed subvariety of M(X, d, r) consisting of all the stable bundles E with det E = L.

scholarly journals On the Negativity of Moduli Spaces for Polarized Manifolds

2021 ◽  
Author(s):  
Kang Zuo
Keyword(s):  
Line Bundle ◽  
Moduli Spaces ◽  
Complex Analysis ◽  
Projective Varieties ◽  
Canonical Line Bundle ◽  
Characteristic Varieties ◽  
Almost All ◽  
Complex Projective ◽  
Made In

AbstractGiven a log base space (Y, S), parameterizing a smooth family of complex projective varieties with semi-ample canonical line bundle, we briefly recall the construction of the deformation Higgs sheaf and the comparison map on (Y, S) made in the work by Viehweg–Zuo. While almost all hyperbolicities in the sense of complex analysis such as Brody, Kobayashi, big Picard and Viehweg hyperbolicities of the base U = Y ∖ S (under some technical assumptions) follow from the negativity of the kernel of the deformation Higgs bundle we pose a conjecture on the topological hyperbolicity on U. In order to study the rigidity problem we then introduce the notions of the length and characteristic varieties of a family f : X → Y, which provide an infinitesimal characterization of products of sub log pairs in (Y, S) and an upper bound for the number of subvarieties appearing as factors in such a product. We formulate a conjecture on a characterization of non-rigid families of canonically polarized varieties.

scholarly journals AUTOMORPHISMS OF MODULI SPACES OF SYMPLECTIC BUNDLES

2012 ◽  
Vol 23 (05) ◽  
pp. 1250052 ◽  
Author(s):  
INDRANIL BISWAS ◽  
TOMAS L. GÓMEZ ◽  
VICENTE MUÑOZ
Keyword(s):  
Automorphism Group ◽  
Line Bundle ◽  
Moduli Space ◽  
Moduli Spaces ◽  
Symplectic Form ◽  
Projective Curve ◽  
Smooth Complex ◽  
Complex Projective ◽  
Complex Projective Curve

Let X be an irreducible smooth complex projective curve of genus g ≥ 4. Fix a line bundle L on X. Let MSp(L) be the moduli space of semistable symplectic bundles (E, φ : E ⊗ E → L) on X, with the symplectic form taking values in L. We show that the automorphism group of MSp(L) is generated by the automorphisms of the form E ↦ E ⊗ M, where [Formula: see text], together with the automorphisms induced by automorphisms of X.

scholarly journals On the unirationality of moduli spaces of pointed curves

2021 ◽  
Author(s):  
Hanieh Keneshlou ◽  
Fabio Tanturri
Keyword(s):  
Moduli Space ◽  
Moduli Spaces ◽  
Smooth Curves ◽  
Projective Curves ◽  
G 12 ◽  
G 11 ◽  
Marked Points ◽  
G 13

AbstractWe show that$$\mathcal {M}_{g,n}$$Mg,n, the moduli space of smooth curves of genusgtogether withnmarked points, is unirational for$$g=12$$g=12and$$2 \le n\le 4$$2≤n≤4and for$$g=13$$g=13and$$1 \le n \le 3$$1≤n≤3, by constructing suitable dominant families of projective curves in$$\mathbb {P}^1 \times \mathbb {P}^2$$P1×P2and$$\mathbb {P}^3$$P3respectively. We also exhibit several new unirationality results for moduli spaces of smooth curves of genusgtogether withnunordered points, establishing their unirationality for$$g=11, n=7$$g=11,n=7and$$g=12, n =5,6$$g=12,n=5,6.

scholarly journals Reachable sheaves on ribbons and deformations of moduli spaces of sheaves

2017 ◽  
Vol 28 (12) ◽  
pp. 1750086
Author(s):  
Jean-Marc Drézet
Keyword(s):  
Line Bundle ◽  
Moduli Spaces ◽  
Coherent Sheaf ◽  
Manuscripta Math ◽  
Projective Curve ◽  
Smooth Curves ◽  
Coherent Sheaves ◽  
Moduli Spaces Of Sheaves ◽  
Irreducible Components ◽  
Torsion Free

A primitive multiple curve is a Cohen–Macaulay irreducible projective curve [Formula: see text] that can be locally embedded in a smooth surface, and such that [Formula: see text] is smooth. In this case, [Formula: see text] is a line bundle on [Formula: see text]. If [Formula: see text] is of multiplicity 2, i.e. if [Formula: see text], [Formula: see text] is called a ribbon. If [Formula: see text] is a ribbon and [Formula: see text], then [Formula: see text] can be deformed to smooth curves, but in general a coherent sheaf on [Formula: see text] cannot be deformed in coherent sheaves on the smooth curves. It has been proved in [Reducible deformations and smoothing of primitive multiple curves, Manuscripta Math. 148 (2015) 447–469] that a ribbon with associated line bundle [Formula: see text] such that [Formula: see text] can be deformed to reduced curves having two irreducible components if [Formula: see text] can be written as [Formula: see text] where [Formula: see text] are distinct points of [Formula: see text]. In this case we prove that quasi-locally free sheaves on [Formula: see text] can be deformed to torsion-free sheaves on the reducible curves with two components. This has some consequences on the structure and deformations of the moduli spaces of semi-stable sheaves on [Formula: see text].

Hitchin pairs on reducible curves

2018 ◽  
Vol 29 (03) ◽  
pp. 1850015 ◽  
Author(s):  
Usha N. Bhosle
Keyword(s):  
Moduli Space ◽  
Moduli Spaces ◽  
Disjoint Union ◽  
Higgs Bundles ◽  
Projective Curve ◽  
Birational Morphism ◽  
Smooth Curves ◽  
Irreducible Components ◽  
Proper Map ◽  
The Relationship

We define semistable generalized parabolic Hitchin pairs (GPH) on a disjoint union [Formula: see text] of integral smooth curves and construct their moduli spaces. We define a Hitchin map on the moduli space of GPH and show that it is a proper map. We construct moduli spaces of semistable Hitchin pairs on a reducible projective curve [Formula: see text]. When [Formula: see text] is the normalization of [Formula: see text], we give a birational morphism [Formula: see text] from the moduli space [Formula: see text] of good GPH on [Formula: see text] to the moduli space [Formula: see text] of Hitchin pairs on [Formula: see text] and show that the Hitchin map on [Formula: see text] induces a proper Hitchin map on [Formula: see text]. We determine the fibers of the Hitchin maps. We study the relationship between representations of the (topological) fundamental group of [Formula: see text] and Higgs bundles on [Formula: see text]. We show that if all the irreducible components of [Formula: see text] are smooth, then the Hitchin map is defined on the entire moduli space [Formula: see text].

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