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Related papers: Tame class field theory for arithmetic schemes

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For a connected regular scheme X, flat and of finite type over Spec(Z), we construct a reciprocity homomorphism \rho_X: C_X --> \pi_1^\ab(X), which is surjective and whose kernel is the connected component of the identity. The (topological)…

Number Theory · Mathematics 2009-03-17 Moritz Kerz , Alexander Schmidt

We give an intrinsic parametrisation of the set of tamely ramified extensions of a local field with finite residue field and bring to the fore the role played by group cohomology. We show that two natural definitions of the cohomology class…

Number Theory · Mathematics 2017-02-16 Chandan Singh Dalawat , Jung-Jo Lee

We prove a duality theorem for the $p$-adic etale motivic cohomology of a variety $U$ which is the complement of a divisor on a smooth projective variety over $\F_p$. This extends the duality theorems of Milne and Jannsen-Saito-Zhao. The…

Algebraic Geometry · Mathematics 2021-04-08 Rahul Gupta , Amalendu Krishna

Let K be an algebraically closed field of characteristic zero. We study the tame isotropy group Tame_D(K[X,Y]) of locally finite derivations of the polynomial ring K[X,Y], using Van den Essen's classification up to conjugation. For each…

Algebraic Geometry · Mathematics 2026-04-07 Luis Cid , Marcelo Veloso

We show the existence of good hyperplane sections for schemes over discrete valuation rings with good or (quasi) semistable reduction, and the existence of good Lefschetz pencils for schemes with good reduction or ordinary quadratic…

Algebraic Geometry · Mathematics 2009-11-10 Uwe Jannsen , Shuji Saito

We consider the class of complete discretely valued fields such that the residue field is of prime characteristic p and the cardinality of a $p$-base is 1. This class includes two-dimensional local and local-global fields. A new definition…

Number Theory · Mathematics 2015-06-26 Igor B. Zhukov

In this paper we study some special classes of division algebras over a Laurent series field with arbitrary residue field. We call the algebras from these classes as splittable and good splittable division algebras. It is shown that these…

Number Theory · Mathematics 2007-05-23 Alexander Zheglov

We identify a class of symmetric algebras over a complete discrete valuation ring $\mathcal O$ of characteristic zero to which the characterisation of Kn\"orr lattices in terms of stable endomorphism rings in the case of finite group…

Representation Theory · Mathematics 2018-03-16 Florian Eisele , Michael Geline , Radha Kessar , Markus Linckelmann

This paper concerns pairs of models of the theory of the differential field of logarithmic-exponential transseries that are tame as a pair of real closed fields. That is, the smaller model is bounded inside the larger model and there exists…

Logic · Mathematics 2024-08-14 Nigel Pynn-Coates

We introduce three notion of tameness of the Nori fundamental group scheme for a normal quasiprojective variety $X$ over an algebraically closed field. It is proved that these three notions agree if $X$ admits a smooth completion with…

Algebraic Geometry · Mathematics 2025-06-16 Indranil Biswas , Manish Kumar , A. J. Parameswaran

We prove that the the kernel of the reciprocity map for a product of curves over a $p$-adic field with split semi-stable reduction is divisible. We also consider the $K_1$ of a product of curves over a number field.

Number Theory · Mathematics 2007-10-15 Takao Yamazaki

Let $k$ be a field, $X$ a variety with tame quotient singularities and $\tilde{X}\to X$ a resolution of singularities. Any smooth rational point $x\in X(k)$ lifts to $\tilde{X}$ by the Lang-Nishimura theorem, but if $x$ is singular this…

Algebraic Geometry · Mathematics 2023-11-29 Giulio Bresciani

We show that compatible systems of $\ell$-adic sheaves on a scheme of finite type over the ring of integers of a local field are compatible along the boundary up to stratification. This extends a theorem of Deligne on curves over a finite…

Algebraic Geometry · Mathematics 2019-11-13 Qing Lu , Weizhe Zheng

We show that every smooth projective curve over a finite field k admits a finite tame morphism to the projective line over k. Furthermore, we construct a curve with no such map when k is an infinite perfect field of characteristic two. Our…

Algebraic Geometry · Mathematics 2021-10-05 Kiran S. Kedlaya , Daniel Litt , Jakub Witaszek

We study the group Tame($\mathbf A^3$) of tame automorphisms of the 3-dimensional affine space, over a field of characteristic zero. We recover, in a unified and (hopefully) simplified way, previous results of Kuroda, Shestakov, Umirbaev…

Group Theory · Mathematics 2021-10-08 Stéphane Lamy

We develop a theory of residues for arithmetic surfaces, establish the reciprocity law around a point, and use the residue maps to explicitly construct the dualizing sheaf of the surface. These are generalisations of known results for…

Number Theory · Mathematics 2011-01-17 Matthew Morrow

Usually the boundary map in K-theory localization only gives the tame symbol at $K_{2}$. It sees the tamely ramified part of the Hilbert symbol, but no wild ramification. Gillet has shown how to prove Weil reciprocity using such boundary…

K-Theory and Homology · Mathematics 2023-01-18 Oliver Braunling

We develop class field theory of curves over $p$-adic fields which extends the unramified theory of S. Saito. The class groups which approximate abelian \'etale fundamental groups of such curves are introduced in the terms of algebraic…

Number Theory · Mathematics 2008-03-18 Toshiro Hiranouchi

We study for rationally connected varieties $X$ the group of degree 2 integral homology classes on $X$ modulo those which are algebraic. We show that the Tate conjecture for divisor classes on surfaces defined over finite fields implies…

Algebraic Geometry · Mathematics 2012-01-17 Claire Voisin

The theory of reciprocity sheaves due to Kahn-Saito-Yamazaki is a powerful framework to study invariants of smooth varieties via invariants of pairs $(X,D)$ of a variety $X$ and a divisor $D$. We develop a generalization of this theory…

Algebraic Geometry · Mathematics 2024-01-01 Junnosuke Koizumi , Hiroyasu Miyazaki