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Let $X$ be a smooth projective variety. Define a stable map $f:C\to X$ to be "eventually smoothable" if there is an embedding $X\hookrightarrow\mathbb{P}^N$ such that $(C,f)$ occurs as the limit of a $1$-parameter family of stable maps to…

Algebraic Geometry · Mathematics 2025-02-25 Fatemeh Rezaee , Mohan Swaminathan

We show exactness of the homotopy sequence for the logarithmic fundamental group in the case of log smooth, finitely presented, proper and saturated morphisms of fs log schemes over a field. This generalizes earlier results of Hoshi in the…

Algebraic Geometry · Mathematics 2026-03-23 Mattia Talpo

We prove, under suitable conditions, that there exist wall-crossing and reduction morphisms for moduli spaces of stable log pairs in all dimensions as one varies the coefficients of the divisor.

Algebraic Geometry · Mathematics 2023-01-27 Kenneth Ascher , Dori Bejleri , Giovanni Inchiostro , Zsolt Patakfalvi

We prove that every quasi-projective semi log canonical pair has a quasi-log structure with several good properties. It implies that various vanishing theorems, torsion-free theorem, and the cone and contraction theorem hold for semi log…

Algebraic Geometry · Mathematics 2013-10-29 Osamu Fujino

We study the circumstances under which one can reconstruct a stack from its associated functor of isomorphism classes. This is possible surprisingly often: we show that many of the standard examples of moduli stacks are determined by their…

Algebraic Geometry · Mathematics 2018-06-18 Max Lieblich , Brian Osserman

Given a finite modular tensor category, we associate with each compact surface with boundary a cochain complex in such a way that the mapping class group of the surface acts projectively on its cohomology groups. In degree zero, this action…

Quantum Algebra · Mathematics 2023-09-19 Simon Lentner , Svea Nora Mierach , Christoph Schweigert , Yorck Sommerhaeuser

This is a paper in a series that studies smooth relative Lie algebra homologies and cohomologies based on the theory of formal manifolds and formal Lie groups. In three previous papers, we introduce the notion of formal manifolds and study…

Differential Geometry · Mathematics 2025-01-22 Fulin Chen , Binyong Sun , Chuyun Wang

The Butcher group is a powerful tool to analyse integration methods for ordinary differential equations, in particular Runge--Kutta methods. Recently, a natural Lie group structure has been constructed for this group. Unfortunately, the…

Group Theory · Mathematics 2016-05-12 Geir Bogfjellmo , Alexander Schmeding

Interpreting the syzygy theorem for tame modules over posets in the setting of derived categories of subanalytically constructible sheaves proves two conjectures due to Kashiwara and Schapira concerning the existence of stratifications of…

Algebraic Topology · Mathematics 2023-03-13 Ezra Miller

This paper is devoted to topological phenomena in normal metals with rather complicated Fermi surface. The results of the article are based on the deep topological theorems concerning the geometry of non-compact plane sections of level…

Condensed Matter · Physics 2009-10-30 S. P. Novikov , A. Ya. Maltsev

I extend the definitions of schemes relative to monoids with zero - and therefore, toric geometry - to the world of formal schemes. This expands the usual framework to include, for instance, models for Mumford's degenerating Abelian…

Algebraic Geometry · Mathematics 2015-05-29 Andrew W. Macpherson

Let $\mathbb{G}$ denote a higher rank $\mathbb R$-split simple Lie group of the following type: $SL(n,\mathbb R)$, $SO_o(m,m)$, $E_{6(6)}$, $E_{7(7)}$ and $E_{8(8)}$, where $m\geq 4$ and $n \geq 3$. We study the cohomological equation for…

Dynamical Systems · Mathematics 2018-09-24 James Tanis , Zhenqi Jenny Wang

We study the dynamical properties of irregular model sets and show that the translation action on their hull always admits an infinite independence set. The dynamics can therefore not be tame and the topological sequence entropy is strictly…

Dynamical Systems · Mathematics 2018-11-16 Gabriel Fuhrmann , Eli Glasner , Tobias Jäger , Christian Oertel

We describe a new approach to the definition of the moduli functor of stable varieties. While there is wide agreement as to what classes of varieties should appear, the notion of a family of stable surfaces is quite subtle, as key numerical…

Algebraic Geometry · Mathematics 2009-04-21 Dan Abramovich , Brendan Hassett

This paper proves a result on the existence of finite flat scheme covers of Deligne-Mumford stacks. This result is used to prove that a large class of smooth Deligne-Mumford stacks with affine moduli space are quotient stacks, and in the…

Algebraic Geometry · Mathematics 2016-09-07 Andrew Kresch , Angelo Vistoli

In casual discussion, a stack is often described as a variety (the coarse space) together with stabilizer groups attached to some of its subvarieties. However, this description does not uniquely specify the stack. Our main result shows that…

Algebraic Geometry · Mathematics 2015-03-19 Anton Geraschenko , Matthew Satriano

We give a classification theorem of certain geometric objects, called torsors over the sheaf of K-theory spaces, in terms of Tate vector bundles. This allows us to present a very natural and simple, alternative approach to the Tate central…

K-Theory and Homology · Mathematics 2014-05-06 Sho Saito

We study contact structures on smooth complex projective varieties with a simple normal crossing divisor, generalizing some well-known results concerning the non-logarithmic case. In particular, we describe the structure of elementary log…

Algebraic Geometry · Mathematics 2024-04-02 Adrian Langer

The logarithmic multiplicative group is a proper group object in logarithmic schemes, which morally compactifies the usual multiplicative group. We study the structure of the stacks of logarithmic maps from rational curves to this…

Algebraic Geometry · Mathematics 2020-03-31 Dhruv Ranganathan , Jonathan Wise

On objects of a triangulated category with a stability condition, we construct a topology.

Algebraic Geometry · Mathematics 2007-05-23 So Okada