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Given a smooth scheme X with an action by an affine algebraic group G, we give a formula to compute the Nisnevich sheaf of the motivic connected components of the quotient stack [X/G] in the case of an orbifold. We apply it to identify all…

Algebraic Geometry · Mathematics 2024-12-09 Neeraj Deshmukh , Suraj Yadav

We generalise Kahn, Miyazaki, Saito, Yamazaki's theory of modulus pairs to pairs $(X, D)$ consisting of a qcqs scheme $X$ equipped with an effective Cartier divisor $D$ representing a ramification bound. We develop theories of sheaves on…

Algebraic Geometry · Mathematics 2021-06-25 Shane Kelly , Hiroyasu Miyazaki

We prove the existence of fine moduli spaces of simple coherent sheaves on families of irreducible curves. Our proof is based on the existence of a universal upper bound of the Castelnuovo-Mumford regularity of such sheaves, which we…

Algebraic Geometry · Mathematics 2013-05-03 Igor Burban , Bernd Kreussler

We give a criterion for the projectivisation of a reflexive sheaf on a klt space to be induced by a projective representation of the fundamental group of the smooth locus. This criterion is then applied to give a characterisation of finite…

Algebraic Geometry · Mathematics 2022-07-25 Daniel Greb , Stefan Kebekus , Thomas Peternell

We use the theory of cubic structures to give a fixed point Riemann-Roch formula for the equivariant Euler characteristics of coherent sheaves on projective flat schemes over Z with a tame action of a finite abelian group. This formula…

Number Theory · Mathematics 2007-05-23 T. Chinburg , G. Pappas , M. Taylor

We study the infinitesimal rigidity of equivariant minimal maps from the universal cover of a smooth oriented surface (possibly non-compact) into a Riemannian symmetric space, focusing on representations arising from cyclic harmonic…

Differential Geometry · Mathematics 2026-05-12 Qiongling Li , Junming Zhang

We develop the theory of geometric Eisenstein series and constant term functors for $\ell$-adic sheaves on stacks of bundles on the Fargues-Fontaine curve. In particular, we prove essentially optimal finiteness theorems for these functors,…

Number Theory · Mathematics 2024-09-17 Linus Hamann , David Hansen , Peter Scholze

In this thesis we give two applications of Ayoub's motivic nearby cycles functor: First we give a generalization of Grothendieck's classical local monodromy theorem. In the classical setup we show that the inertia group acts…

Algebraic Geometry · Mathematics 2023-05-08 Benedikt Preis

Let $k$ be a field of characteristic zero containing all roots of unity and $K=k((t))$. We build a ring morphism from the Grothendieck group of semi-algebraic sets over $K$ to the Grothendieck group of motives of rigid analytic varieties…

Algebraic Geometry · Mathematics 2017-07-21 Arthur Forey

We prove a rigidity property in non-Archimedean dynamics, reminiscent of Zdunik theorem in complex dynamics: every rational map whose equilibrium measure charges an interval in the Berkovich projective line is affine Bernoulli. Our proof is…

Dynamical Systems · Mathematics 2026-01-27 Charles Favre , Juan Rivera-Letelier

We identify a close relationship between stable sheaf cohomology for polynomial functors applied to the cotangent bundle on projective space, and Koszul--Ringel duality on the category of strict polynomial functors as described in the work…

Representation Theory · Mathematics 2025-09-12 Claudiu Raicu , Keller VandeBogert

Let $f\colon\mathbb{T}^d\to\mathbb{T}^d$ be an Anosov diffeomorphism whose linearization $A\in{\rm GL}(d,\mathbb{Z})$ is irreducible. Assume that $f$ is also absolutely partially hyperbolic where a weak stable subbundle is considered as the…

Dynamical Systems · Mathematics 2022-07-05 Andrey Gogolev , Yi Shi

We generalize the notion of a small sheaf of sets over a topological space or manifold to define the notion of a small stack of groupoids over an \'etale topological or differentiable stack. We then provide a construction analogous to the…

Algebraic Topology · Mathematics 2012-03-28 David Carchedi

In this work we prove a sharp quantitative form of Liouville's theorem, which asserts that, for all $n\geq 3$, the weakly conformal maps of $\mathbb S^{n-1}$ with degree $\pm 1$ are M\"obius transformations. In the case $n=3$ this estimate…

Analysis of PDEs · Mathematics 2023-06-01 André Guerra , Xavier Lamy , Konstantinos Zemas

We construct a perfect version of Morel--Voevodsky's motivic homotopy category over a perfect base scheme in positive characteristic. By checking the axioms of a coefficient system, we establish a six-functor formalism. We show that…

Algebraic Geometry · Mathematics 2025-10-03 Christian Dahlhausen , Jeroen Hekking , Storm Wolters

We investigate the positivity and extension of invertible sheaves on group homogeneous spaces over coherent bases. Bypassing the failure of standard limit arguments and the classical Weil--Cartier correspondence, we develop a valuative…

Algebraic Geometry · Mathematics 2026-03-24 Ning Guo

We solve a motivic version of the Adams conjecture with the exponential characteristic of the base field inverted. In the way of the proof we obtain a motivic version of mod k Dold theorem and give a motivic version of Brown's trick…

K-Theory and Homology · Mathematics 2025-05-09 Alexey Ananyevskiy , Elden Elmanto , Oliver Röndigs , Maria Yakerson

We construct the motive of an algebraic stack in the Nisnevich topology. For stacks which are Nisnevich locally quotient stacks, we give a presentation of the motive in terms of simplicial schemes. We also show that for quotient stacks the…

Algebraic Geometry · Mathematics 2023-06-21 Utsav Choudhury , Neeraj Deshmukh , Amit Hogadi

We show a stability-type theorem for foliations on projective spaces which arise as pullbacks of foliations with a split tangent sheaf on weighted projective spaces. As a consequence, we will be able to construct many irreducible components…

Algebraic Geometry · Mathematics 2025-01-14 Javier Gargiulo Acea , Ariel Molinuevo , Federico Quallbrunn , Sebastián Lucas Velazquez

We discuss two extensions of results conjectured by Nick Kuhn about the non-realization of unstable algebras as the mod $p$ singular cohomology of a space, for $p$ a prime. The first extends and refines earlier work of the second and fourth…

Algebraic Topology · Mathematics 2015-02-06 Nguyen The Cuong , Gérald Gaudens , Geoffrey Powell , Lionel Schwartz