English
Related papers

Related papers: A note on \'etale endomorphisms of normal schemes

200 papers

Let $X$ be a complex projective bundle. We prove that $X$ admits an endomorphism of degree $>1$ and commuting with the projection to the base, if and only if $X$ trivializes after a finite covering. When $X$ is the projectivization of a…

Algebraic Geometry · Mathematics 2007-05-23 Ekaterina Amerik

We examine varieties of epigroups as unary semigroups, that is semigroups equipped with an additional unary operation of pseudoinversion. The article contains two main results. The first of them indicates a countably infinite family of…

Group Theory · Mathematics 2020-01-22 S. V. Gusev , B. M. Vernikov

The aim of this article is to prove that, under certain conditions, an affine flat normal scheme that is of finite type over a local Dedekind scheme in mixed characteristic admits infinitely many normal effective Cartier divisors. For the…

Commutative Algebra · Mathematics 2026-03-03 Jun Horiuchi , Kazuma Shimomoto

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 define a theory of etale motives over a noetherian scheme. This provides a system of categories of complexes of motivic sheaves with integral coefficients which is closed under the six operations of Grothendieck. The rational part of…

Algebraic Geometry · Mathematics 2019-02-20 Denis-Charles Cisinski , Frédéric Déglise

In the study of homology cobordisms, knot concordance and link concordance, the following technical problem arises frequently: let $\pi$ be a group and let $M \to N$ be a homomorphism between projective $\Z[\pi]$-modules such that $\Z_p…

Geometric Topology · Mathematics 2010-12-02 Stefan Friedl , Mark Powell

Given a surjective ring homomorphism, we study when the induced group homomorphism on unit groups is surjective. To this end, we introduce notions of generalized inverses and units, as well as a class of rings such that the set of closed…

Commutative Algebra · Mathematics 2017-10-17 Justin Chen

Baer's Criterion of injectivity implies that injectivity of a module is a factorization property w.r.t. a single monomorphism. Using the notion of a cotorsion pair, we study generalizations and dualizations of factorization properties in…

Rings and Algebras · Mathematics 2019-12-10 Jan Šaroch , Jan Trlifaj

We formulate analogues, for Noetherian local $\mathbb Q$-algebras which are not necessarily regular, of the injectivity part of Gersten's conjecture in algebraic $K$-theory, and prove them in various cases. Our results suggest that the…

Algebraic Geometry · Mathematics 2016-07-22 Amalendu Krishna , Matthew Morrow

For a non-isotrivial family of surfaces of general type over a complex projective curve, we give upper bounds for the degree of the direct images of powers of the relative dualizing sheaf. They imply that, fixing the curve and the possible…

Algebraic Geometry · Mathematics 2009-10-31 E. Bedulev , E. Viehweg

Let S be a closed orientable surface of genus at least two, and let C be an arbitrary (complex) projective structure on S. We show that there is a decomposition of S into pairs of pants and cylinders such that the restriction of C to each…

Geometric Topology · Mathematics 2010-12-30 Shinpei Baba

We formulate a lattice theoretical Jordan normal form theorem for certain nilpotent lattice maps satisfying the so called JNB conditions. As an application of the general results, we obtain a transparent Jordan normal base of a nilpotent…

Rings and Algebras · Mathematics 2007-05-23 Jeno Szigeti

We prove new automorphy lifting theorems for residually reducible Galois representations of unitary type in which the residual representation is permitted to have an arbitrary number of irreducible constituents.

Number Theory · Mathematics 2020-08-14 Patrick B. Allen , James Newton , Jack A. Thorne

We make explicit certain results around the Galois correspondence in the context of definable automorphism groups, and point out the relation to some recent papers dealing with the Galois theory of algebraic differential equations when the…

Logic · Mathematics 2016-07-20 Omar Leon Sanchez , Anand Pillay

We construct injective hulls and projective covers in categories of generalized uniform hypergraphs which generalizes the constructions in the category of quivers and the category of undirected graphs. While the constructions are not…

Combinatorics · Mathematics 2018-07-26 Martin Schmidt

We associate to any irreducible germ S of complex quasi-ordinary hypersurface an analytically invariant semigroup. We deduce a direct proof (without passing through their embedded topological invariance) of the analytical invariance of the…

Complex Variables · Mathematics 2007-05-23 Patrick Popescu-Pampu

It is well known that if G is a finite group then the group of endotrivial modules is finitely generated. In this paper we prove that for an arbitrary finite group scheme G, and for any fixed integer n > 0, there are only finitely many…

Group Theory · Mathematics 2011-04-04 Jon F. Carlson , Daniel K. Nakano

We define the notion of an additive model category, and we prove that any additive, stable, combinatorial model category has a natural enrichment over symmetric spectra based on simplicial abelian groups. As a consequence, every object in…

Algebraic Topology · Mathematics 2007-05-23 Daniel Dugger , Brooke Shipley

For a complex polynomial in two variables we study the morphism induced in homology by the embedding of an irregular fiber in a regular neighborhood of it. We give necessary and sufficient conditions for this morphism to be injective,…

Algebraic Geometry · Mathematics 2007-05-23 Arnaud Bodin

Let $X$ be a normal compact K\"ahler space of dimension $n$. A surjective endomorphism $f$ of such $X$ is int-amplified if $f^*\xi-\xi=\eta$ for some K\"ahler classes $\xi$ and $\eta$. First, we show that this definition generalizes the…

Algebraic Geometry · Mathematics 2022-03-15 Guolei Zhong