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Related papers: Local properties of good moduli spaces

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We show that near closed points with linearly reductive stabilizer, Artin stacks are formally locally quotient stacks by the stabilizer. We conjecture that the statement holds etale locally and we provide some evidence for this conjecture.…

Algebraic Geometry · Mathematics 2017-12-12 Jarod Alper

The goal of this note is to introduce an interesting question proposed by D. Rydh on an analytic version of the local structure of Artin stacks saying that near points with linearly reductive stabilizers, Artin stacks are \'etale-locally…

Algebraic Geometry · Mathematics 2024-08-27 An Khuong Doan

We develop the theory of associating moduli spaces with nice geometric properties to arbitrary Artin stacks generalizing Mumford's geometric invariant theory and tame stacks.

Algebraic Geometry · Mathematics 2009-10-19 Jarod Alper

Let $\mathcal{X}$ be a smooth Artin stack with properly stable good moduli space $\pi\colon\mathcal{X} \to X$. The purpose of this paper is to prove that a simple geometric criterion can often characterize when the moduli space $X$ is…

Representation Theory · Mathematics 2024-02-16 Dan Edidin , Matthew Satriano , Spencer Whitehead

We develop a theory of good moduli spaces for derived Artin stacks, which naturally generalizes the classical theory of good moduli spaces introduced by Alper. As such, many of the fundamental results and properties regarding good moduli…

Algebraic Geometry · Mathematics 2026-05-15 Eric Ahlqvist , Jeroen Hekking , Michele Pernice , Michail Savvas

Drawing on the theory of Minimal Model Program singularities for foliations, we define relative canonical and log-canonical singularities for algebraic stacks with finite generic stabilisers. We show that if a point has log-canonical…

Algebraic Geometry · Mathematics 2026-03-27 Federico Bongiorno

We provide necessary and sufficient conditions for when an algebraic stack admits a good moduli space and prove a semistable reduction theorem for points of algebraic stacks equipped with a $\Theta$-stratification. These results provide a…

Algebraic Geometry · Mathematics 2024-02-26 Jarod Alper , Daniel Halpern-Leistner , Jochen Heinloth

We prove a general criterion for an algebraic stack to admit a good moduli space. This result may be considered as a weak analog of the Keel-Mori theorem, which guarantees the existence of a coarse moduli space for a separated…

Algebraic Geometry · Mathematics 2012-06-07 Jarod Alper , David Ishii Smyth

This paper is largely concerned with constructing coarse moduli spaces for Artin stacks. The main purpose of this paper is to introduce the notion of stability on an arbitrary Artin stack and construct a coarse moduli space for the open…

Algebraic Geometry · Mathematics 2010-07-05 Isamu Iwanari

We prove that an algebraic stack with affine stabilizers over an arbitrary base is \'etale-locally a quotient stack around any point with a linearly reductive stabilizer. This generalizes earlier work by the authors of this article (stacks…

Algebraic Geometry · Mathematics 2025-04-07 Jarod Alper , Jack Hall , David Rydh

We use techniques of Alper-Hall-Rydh to prove a local structure theorem for smooth morphisms between smooth stacks around points with linearly reductive stabilizers. This implies that the good moduli space of a smooth stack over a base has…

Algebraic Geometry · Mathematics 2026-05-12 Mark Andrea de Cataldo , Andres Fernandez Herrero , Andrés Ibáñez Núñez

In this paper we study the local geometry of the stack of pointed $A_r$-stable curves. In particular, we analyze the deformation theory of $A_r$-stable curves and their automorphism groups in order to study the combinatorics of families of…

Algebraic Geometry · Mathematics 2026-04-01 Davide Gori , Ludvig Modin , Michele Pernice

This informal note provides some elementary examples to motivate the local structural results of [1] on the moduli space of genus one stable maps to projective space. The hope is that these examples will be helpful for graduate students to…

Algebraic Geometry · Mathematics 2011-06-16 Yi Hu

In this note we show that an Artin stack with finite inertia stack is etale locally isomorphic to the quotient of an affine scheme by an action of a general linear group.

Algebraic Geometry · Mathematics 2010-07-05 Isamu Iwanari

Moduli of vector bundles on stacky curves behave similarly to moduli of vector bundles on curves, except there are additional numerical invariants giving many different notions of stability. We apply the existence criterion for good moduli…

Algebraic Geometry · Mathematics 2024-07-08 Chiara Damiolini , Victoria Hoskins , Svetlana Makarova , Lisanne Taams

We prove that every algebraic stack, locally of finite type over an algebraically closed field with affine stabilizers, is \'etale-locally a quotient stack in a neighborhood of a point with a linearly reductive stabilizer group. The proof…

Algebraic Geometry · Mathematics 2021-01-19 Jarod Alper , Jack Hall , David Rydh

We give a complete characterization of degree two rational maps with potential good reduction over local fields. We show this happens exactly when the map corresponds to an integral point in the moduli space. We detail an algorithm by which…

Dynamical Systems · Mathematics 2012-05-15 Diane Yap

We provide a geometric construction of a sequence of modular blowups of the Artin stack parameterizing pre-stable pairs consisting of a genus-two nodal curve and a smooth divisor. The resulting stack locally diagonalizes the tautological…

Algebraic Geometry · Mathematics 2025-09-08 Yi Hu , Jun Li , Jingchen Niu

We prove formal GAGA for good moduli space morphisms under an assumption of "enough vector bundles" (which holds for instance for quotient stacks). This supports the philosophy that though they are non-separated, good moduli space morphisms…

Algebraic Geometry · Mathematics 2015-07-02 Anton Geraschenko , David Zureick-Brown

We give a variant of Artin algebraization along closed subschemes and closed substacks. Our main application is the existence of \'etale, smooth, or syntomic neighborhoods of closed subschemes and closed substacks. In particular, we prove…

Algebraic Geometry · Mathematics 2022-05-19 Jarod Alper , Daniel Halpern-Leistner , Jack Hall , David Rydh
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