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We construct a new compactification of the moduli space of maps from pointed nonsingular projective stable curves to a nonsingular projective variety with prescribed ramification indices at the points. It is shown to be a proper…

Algebraic Geometry · Mathematics 2011-06-01 Bumsig Kim , Andrew Kresch , Yong-Geun Oh

Let $X$ be a projective variety with an action of a reductive group $G$. Each ample $G$-line bundle $L$ on $X$ defines an open subset $X^{\rm ss}(L)$ of semi-stable points. Following Dolgachev and Hu, define a GIT-class as the set of…

Algebraic Geometry · Mathematics 2007-05-23 Nicolas Ressayre

To every oriented tree, we associate a moduli problem for sheaves over a projective manifold $X$. We define the corresponding notion of semistability and establish the existence of moduli spaces. Applying the results to the tree *->*, we…

Algebraic Geometry · Mathematics 2007-05-23 Alexander Schmitt

We construct positive-genus analogues of Welschinger's invariants for many real symplectic manifolds, including the odd-dimensional projective spaces and the renowned quintic threefold. In some cases, our invariants provide lower bounds for…

Symplectic Geometry · Mathematics 2018-02-27 Penka Georgieva , Aleksey Zinger

This is the first in a projected series of three papers in which we construct the second flip in the log minimal model program for $\bar{M}_g$. We introduce the notion of a weakly proper algebraic stack, which may be considered as an…

Algebraic Geometry · Mathematics 2015-03-17 Jarod Alper , David Ishii Smyth , Frederick van der Wyck

Let $G$ be a reductive algebraic group over a $p$-adic field or number field $K$, and let $V$ be a $K$-linear faithful representation of $G$. A lattice $\Lambda$ in the vector space $V$ defines a model $\hat{G}_{\Lambda}$ of $G$ over…

Algebraic Geometry · Mathematics 2022-06-03 Milan Lopuhaä-Zwakenberg

Let $C$ be an algebraic smooth complex curve of genus $g>1$. The object of this paper is the study of the birational structure of certain moduli spaces of vector bundles and of coherent systems on $C$ and the comparison of different type of…

Algebraic Geometry · Mathematics 2011-09-27 Michele Bolognesi , Sonia Brivio

We consider geometric invariant theory for \emph{graded additive groups}, groups of the form $\mathbb{G}_a^r\rtimes_w\mathbb{G}_m$ such that the $\mathbb{G}_m$-action on $\mathbb{G}_a^r$ is a scalar multiplication with weight…

Algebraic Geometry · Mathematics 2025-07-17 Yikun Qiao

In this paper we study the geometry of GIT configurations of $n$ ordered points on $\mathbb{P}^1$ both from the the birational and the biregular viewpoint. In particular, we prove that any extremal ray of the Mori cone of effective curves…

Algebraic Geometry · Mathematics 2021-06-14 Michele Bolognesi , Alex Massarenti

We here present rudiments of an approach to geometric actions in noncommutative algebraic geometry, based on geometrically admissible actions of monoidal categories. This generalizes the usual (co)module algebras over Hopf algebras which…

Algebraic Geometry · Mathematics 2009-09-22 Zoran Škoda

Much of arithmetic geometry is concerned with the study of principal bundles. They occur prominently in the arithmetic of elliptic curves and, more recently, in the study of the Diophantine geometry of curves of higher genus. In particular,…

Number Theory · Mathematics 2018-10-17 Minhyong Kim

Let $k$ be a field, let $G$ be a reductive group, and let $V$ be a linear representation of $G$. Let $V//G = Spec(Sym(V^*))^G$ denote the geometric quotient and let $\pi: V \to V//G$ denote the quotient map. Arithmetic invariant theory…

Number Theory · Mathematics 2013-10-30 Manjul Bhargava , Benedict H. Gross , Xiaoheng Wang

A theory of graded manifolds can be viewed as a generalization of differential geometry of smooth manifolds. It allows one to work with functions which locally depend not only on ordinary real variables, but also on $\mathbb{Z}$-graded…

Differential Geometry · Mathematics 2023-03-14 Jan Vysoky

We generalize the classical semi-continuity theorem for GIT (semi)stable loci under variations of linearizations to a relative situation of an equivariant projective morphism from X to an affine base S. As an application to moduli problems,…

Algebraic Geometry · Mathematics 2021-12-09 Lars H. Halle , Klaus Hulek , Ziyu Zhang

We propose Gradient Inversion Transcript (GIT), a novel generative approach for reconstructing training data from leaked gradients. GIT employs a generative attack model, whose architecture is tailored to align with the structure of the…

Machine Learning · Computer Science 2025-05-27 Xinping Chen , Chen Liu

In a natural way, the local diffeomorphisms of a manifold onto itself act on the reference frame bundles of any order and on the bundles associated with them. Due to the transitivity, the invariants by diffeomorphisms of an associated…

Differential Geometry · Mathematics 2017-09-11 Ignacio Sánchez-Rodríguez

Here I give a direct proof that smooth curves with distinct marked points are asymptotically Hilbert stable with respect to a wide range of parameter spaces and linearizations. This result can be used to construct the coarse moduli space of…

Algebraic Geometry · Mathematics 2008-01-09 David Swinarski

We construct the moduli stack of properly balanced vector bundles on semistable curves and we determine explicitly its Picard group. As a consequence, we obtain an explicit description of the Picard groups of the universal moduli stack of…

Algebraic Geometry · Mathematics 2018-06-11 Roberto Fringuelli

We study the action of the group of automorphisms of the projective plane on the Maruyama scheme of sheaves $\mathcal{M}_{P^{2}}(r,c_{1,}c_{2})$ of rank $r$ and Chern classes $c_{1}=0$ and $c_{2}=n$ and obtain sufficient conditions for…

Algebraic Geometry · Mathematics 2007-05-23 Satyajit S Karnik

We study the Borel moment map $\mu_B:T^*(\mathfrak{b}\times \mathbb{C}^n)\rightarrow \mathfrak{b}^*$, given by $(r,s,i,j)\mapsto [r,s]+ij$, and describe our algorithm to construct the geometric invariant theory (GIT) quotients…

Algebraic Geometry · Mathematics 2020-01-28 Mee Seong Im , Meral Tosun