Hyperelliptic Components of the Moduli Spaces of Quadratic Differentials with Prescribed Singularities

具有给定不变量的全纯微分形式的相对周期实现

Relative period realization of holomorphic differentials with prescribed invariants

本文完整描述了黎曼曲面上具有给定零点阶数和超椭圆结构、自旋奇偶性等不变量的全纯微分形式的可实现相对周期表示，回答了Simion Filip的问题。

Combinatorial Classes, Hyperelliptic Loci, and Hodge Integrals

A closed formula is obtained for the integral $\int_{\mathcal{\bar{H}}_g^1}κ_{1}ψ^{2g-2}$ of tautological classes over the locus of hyperelliptic Weierstraß points in the moduli space of curves. As a corollary, a relation between Hodge integrals is obtained. The calculation utilizes the homeomorphism between the moduli space of curves $\mathcal{M}_{g,1}$ and the combinatorial moduli space $\mathcal{M}^{comb}_{g,1}$, a PL-orbifold whose cells are enumerated by fatgraphs. This cell decomposition can be used to naturally construct combinatorial PL-cycles $W_a\subset\mathcal{M}^{comb}_{g,1}$ whose…

Picard groups of moduli spaces of curves with symmetry

We study the Picard groups of moduli spaces of smooth complex projective curves that have a group of automorphisms with a prescribed topological action. One of our main tools is the theory of symmetric mapping class groups. In the first part of the paper, we show that, under mild restrictions, the moduli spaces of smooth curves with an abelian group of automorphisms of a fixed topological type have finitely generated Picard groups. In certain special cases, we are able to compute them exactly. In the second part of the paper, we show that finite abelian level covers of the hyperelliptic locus …

具有 prescribed invariants 的 meromorphic differentials 的 period realization

Period realization of meromorphic differentials with prescribed invariants

本文完整描述了 Riemann 曲面上具有 prescribed zeros 和 poles 阶数、hyperelliptic 结构及 spin parity 的 meromorphic differentials 的可实现 period representations。

The infinite topology of the hyperelliptic locus in Torelli space

Genus $g$ Torelli space is the moduli space of genus $g$ curves of compact type equipped with a homology framing. The hyperelliptic locus is a closed analytic subvariety consisting of finitely many mutually isomorphic components. We use properties of the hyperelliptic Torelli group to show that when $g\geq 3$ these components do not have the homotopy type of a finite CW complex. Specifically, we show that the second rational homology of each component is infinite-dimensional. We give a more detailed description of the topological features of these components when $g=3$ using properties of genu…

双曲面上的对应、组合定理与赫维茨空间

Correspondences on hyperelliptic surfaces, combination theorems, and Hurwitz spaces

本文构造了任意亏格双曲黎曼曲面上结合零亏格富克斯群与布拉施克乘积的对应，给出其解析组合的代数刻画，识别对应模空间为泰希米勒空间与布拉施克空间的乘积，并构造该乘积空间到赫维茨空间的动态自然单射。

GL(2,R)-Invariant Measures in Marked Strata: Generic Marked Points, Earle-Kra for Strata, and Illumination

We classify GL(2,R) invariant point markings over components of strata of Abelian differentials. Such point markings exist only when the component is hyperelliptic and arise from marking Weierstrass points or two points exchanged by the hyperelliptic involution. We show that these point markings can be used to determine the holomorphic sections of the universal curve restricted to orbifold covers of subvarieties of the moduli space of Riemann surfaces that contain a Teichmuller disk. The finite blocking problem is also solved for translation surfaces with dense GL(2,R) orbit.

Connected components of the moduli spaces of Abelian differentials with prescribed singularities

Consider the moduli space of pairs (C,w) where C is a smooth compact complex curve of a given genus and w is a holomorphic 1-form on C with a given list of multiplicities of zeroes. We describe connected components of this space. This classification is important in the study of dynamics of interval exchange transformations and billiards in rational polygons, and in the study of geometry of translation surfaces.

Connecting $p$-gonal loci in the compactification of moduli space

Consider the moduli space $\mathcal{M}_{g}$ of Riemann surfaces of genus $g\geq 2$ and its Deligne-Munford compactification $\bar{\mathcal{M}_{g}}$. We are interested in the branch locus ${\mathcal{B}_{g}}$ for $g>2$, i.e., the subset of $\mathcal{M}_{g}$ consisting of surfaces with automorphisms. It is well-known that the set of hyperelliptic surfaces (the hyperelliptic locus) is connected in $\mathcal{M}_{g}$ but the set of (cyclic) trigonal surfaces is not. By contrast, we show that for $g\geq 5$ the set of (cyclic) trigonal surfaces is connected in $\bar{\mathcal{M}_{g}}$. To do so we exhi…

Moduli spaces of flat tori with prescribed holonomy

We generalise to the genus one case several results of Thurston concerning moduli spaces of flat Euclidean structures with conical singularities on the two dimensional sphere. More precisely, we study the moduli space of flat tori with $n$ cone points and a prescribed holonomy $ρ$. In his paper `Flat Surfaces' Veech has established that under some assumptions on the cone angles, such a moduli space ${\mathcal{F}}_{[ρ]}\subset \mathscr M_{1,n}$ carries a natural geometric structure modeled on the complex hyperbolic space ${\mathbb C}{\mathbb{H} }^{n-1}$ which is not metrically complete. Using s…

Moduli space of meromorphic differentials with marked horizontal separatrices

We study framed translation surfaces corresponding to meromorphic differentials on compact Riemann surfaces, for which a horizontal separatrix is marked for each pole or zero. Such geometric structures naturally appear when studying flat geometry surfaces "near" the Deligne-Mumford boundary.We compute the number of connected components of the corresponding strata, and give a simple topological invariant that distinguishes them. In particular we see that for $g>0$, there are at most two such components, except in the hyperelliptic case.

Combinatorial analysis of the period mapping: topology of 2D fibers

We study the periods mapping from the moduli space of real hyperelliptic curves with marked point on an oriented oval to the euclidean space. The mapping arises in the analysis of Chebyshev construction used in the constrained optimization of the uniform norm of polynomials and rational functions. The decomposition of the moduli space into polyhedra labeled by planar graphs allows to investigate the global topology of low dimensional fibers of the periods mapping.