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In this article we aim to develop from first principles a theory of sum sets and partial sum sets, which are defined analogously to difference sets and partial difference sets. We obtain non-existence results and characterisations. In…

Combinatorics · Mathematics 2012-06-26 Robert S. Coulter , Todd Gutekunst

We generalize to the super context, the known fact that if an affine algebraic group $G$ over a commutative ring $k$ acts freely (in an appropriate sense) on an affine scheme $X$ over $k$, then the dur sheaf $X\tilde{\tilde{/}}G$ of…

Algebraic Geometry · Mathematics 2021-08-10 Akira Masuoka , Taiki Shibata , Yuta Shimada

This paper extends the affine Springer theory developed by Bouthier, Kazhdan, and the second author (see [BKV]) to the mixed characteristic case. In particular, we introduce a theory of perfectly placid perfect infinity stacks and establish…

Representation Theory · Mathematics 2026-01-16 Noam Nissan , Yakov Varshavsky

We give a complete description of the cone of Betti diagrams over a standard graded hypersurface ring of the form k[x,y]/<q>, where q is a homogeneous quadric. We also provide a finite algorithm for decomposing Betti diagrams, including…

Commutative Algebra · Mathematics 2018-04-30 Christine Berkesch , Jesse Burke , Daniel Erman , Courtney Gibbons

We give several related versions of global Grothendieck Duality for unbounded complexes on noetherian formal schemes. The proofs, based on a non-trivial adaptation of Deligne's method for the special case of ordinary schemes, are reasonably…

alg-geom · Mathematics 2008-02-03 Leovigildo Alonso , Ana Jeremias , Joseph Lipman

We show that affine subspaces of Euclidean space are of Khintchine type for divergence under certain multiplicative Diophantine conditions on the parametrizing matrix. This provides evidence towards the conjecture that all affine subspaces…

Number Theory · Mathematics 2020-02-18 Daniel C. Alvey

We describe a new relation between the topology of hypersurface complements, Milnor fibers and degree of gradient mappings. In particular we show that any projective hypersurface has affine parts which are bouquets of spheres. The main…

Algebraic Topology · Mathematics 2007-05-23 Alexandru Dimca , Stefan Papadima

We prove the equidimensionality of affine Deligne-Lusztig varieties in mixed characteristic. This verifies a conjecture made by Rapoport and implies that the results of Nie and Zhou-Zhu can be extended to the whole irreducible components of…

Algebraic Geometry · Mathematics 2025-08-14 Yuta Takaya

In this article we prove in main Theorem A that any infinity type real hyperplane arrangement $\mathcal{H}_n^m$ (Definition 2.11) with the associated normal system $\mathcal{N}$ (Definitions [2.2,2.4] can be represented isomorphically…

Combinatorics · Mathematics 2026-01-21 C. P. Anil Kumar

We establish a Lefschetz hyperplane theorem for the Berkovich analytifications of Jacobians of curves over an algebraically closed non-Archimedean field. Let $J$ be the Jacobian of a curve $X$, and let $W_d \subset J$ be the locus of…

Algebraic Geometry · Mathematics 2020-03-24 Tif Shen

We define the abelian fundamental group with modulus of a regular flat scheme over a discrete valuation ring, taking into account wild ramification along a divisor. Our definition provides a mixed-characteristic analogue of the abelian…

Algebraic Geometry · Mathematics 2025-10-24 Ryosuke Ooe

We investigate flat morphisms of schemes of positive characteristic whose relative Frobenius is an isomorphism, which we call pristine. We show that these give rise to a natural Grothendieck topology that is fine tuned for the localization…

Algebraic Geometry · Mathematics 2026-03-20 Javier Carvajal-Rojas , Axel Stäbler

An effective algorithm of determining Gromov--Witten invariants of smooth hypersurfaces in any genus (subject to a degree bound) from Gromov--Witten invariants of the ambient space is proposed. The Appendix is joint with E. Schulte-Geers.

Algebraic Geometry · Mathematics 2021-08-05 Honglu Fan , Yuan-Pin Lee

We prove that affine maps are uniquely extremal quasiconformal maps on the complement of a well distribute set in the complex plane answering a conjecture from \cite{markovic}. We construct the required Reich sequence using Bergman…

Complex Variables · Mathematics 2025-03-20 Qiliang Luo , Vladimir Marković

We prove a general inequality for estimating the number of points of arbitrary complete intersections over a finite field. This extends a result of Deligne for nonsingular complete intersections. For normal complete intersections, this…

Algebraic Geometry · Mathematics 2009-09-15 Sudhir R. Ghorpade , Gilles Lachaud

The Hilbert scheme of $n$ points in the affine plane contains the open subscheme parametrizing $n$ distinct points in the affine plane, and the closed subscheme parametrizing ideals of codimension $n$ supported at the origin of the affine…

Algebraic Geometry · Mathematics 2014-07-03 Mathias Lederer

In a previous paper {GN2} an effective solution of the lattice point counting problem in general domains in semisimple S-algebraic groups and affine symmetric varieties was established. The method relies on the mean ergodic theorem for the…

Number Theory · Mathematics 2019-02-20 Alexander Gorodnik , Amos Nevo

We introduce a new fundamental group scheme for varieties defined over an algebraically closed field of positive characteristic and we use it to study generalization of some of C. Simpson's results to positive characteristic. We also study…

Algebraic Geometry · Mathematics 2015-03-24 Adrian Langer

Building on results of Arthur and Mok, we extend to (finite volume) complex and quaternionic hyperbolic manifolds the results of arXiv:1004.1085. For the spherical spectrum our results are optimal. Finally, as an application we prove a…

Number Theory · Mathematics 2014-06-17 Nicolas Bergeron , Laurent Clozel

We prove a case of the Grothendieck-Serre conjecture: let $R$ be a Noetherian semilocal flat algebra over a Dedekind domain such that all fibers of $R$ are geometrically regular; let $G$ be a simply-connected reductive $R$-group scheme…

Algebraic Geometry · Mathematics 2023-11-20 Roman Fedorov