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We introduce the notion of a poset scheme and study the categories of quasi-coherent sheaves on such spaces. We then show that smooth poset schemes may be used to obtain categorical resolutions of singularities for usual singular schemes.…

Algebraic Geometry · Mathematics 2010-11-30 V. A. Lunts

We classify four-dimensional quasismooth weighted hypersurfaces with small canonical class, and verify a conjecture of Johnson and Kollar on infinite series of quasismooth hypersurfaces with anticanonical hyperplane section in the case of…

Algebraic Geometry · Mathematics 2022-10-28 Gavin Brown , Alexander Kasprzyk

Let $R \to S$ be a cyclically pure map of Noetherian $\mathbb{Q}$-algebras. In this paper, we show that if $S$ has Du Bois singularities, then $R$ has Du Bois singularities. Our result is new even when $R \to S$ is faithfully flat. Our…

Algebraic Geometry · Mathematics 2026-05-20 Charles Godfrey , Takumi Murayama

We prove that there are no pseudoholomorphic theories of anything other than curves, even if one allows more general spaces than almost complex manifolds. The proof is elementary, except for theories of pseudoholomorphic hypersurfaces,…

Differential Geometry · Mathematics 2010-09-29 Benjamin McKay

In this work, we obtain an unexpected geometric characterization of sphericity of a real-analytic Levi-nondegenerate hypersurface $M\subset\mathbb C^{2}$. We prove that $M$ is spherical if and only if its Segre\,(-Webster) varieties satisfy…

Complex Variables · Mathematics 2016-06-28 Ilya Kossovskiy

In this paper, we analyze the Hessian locus associated to a general cubic hypersurface, by describing for every $n$ its singular locus and its desingularization. The strategy is based on strong connections between the Hessian and the…

Algebraic Geometry · Mathematics 2024-06-18 D. Bricalli , F. F. Favale , G. P. Pirola

We show that k-rational singularities of local complete intersections are k-Du Bois. For hypersurfaces, we characterize k-rationality in terms of the minimal exponent. We also establish some local vanishing results for k-rational and k-Du…

Algebraic Geometry · Mathematics 2024-03-19 Mircea Mustata , Mihnea Popa

We consider singular Q-acyclic surfaces with smooth locus of non-general type. We prove that if the singularities are topologically rational then the smooth locus is C^1- or C*-ruled or the surface is up to isomorphism one of two…

Algebraic Geometry · Mathematics 2014-02-21 Karol Palka

A monoid hypersurface is an irreducible hypersurface of degree d which has a singular point of multiplicity d-1. Any monoid hypersurface admits a rational parameterization, hence is of potential interest in computer aided geometric design.…

Algebraic Geometry · Mathematics 2007-05-23 Pål Hermunn Johansen , Magnus Løberg , Ragni Piene

We study a natural generalization of transversally intersecting smooth hypersurfaces in a complex manifold: hypersurfaces, whose components intersect in a transversal way but may be themselves singular. Such hypersurfaces will be called…

Algebraic Geometry · Mathematics 2018-05-02 Eleonore Faber

We study various measures of irrationality for hypersurfaces of large degree in projective space and other varieties. These include the least degree of a rational covering of projective space, and the minimal gonality of a covering family…

Algebraic Geometry · Mathematics 2019-02-20 Francesco Bastianelli , Pietro De Poi , Lawrence Ein , Robert Lazarsfeld , Brooke Ullery

We know that semi-regular sub-varieties satisfy the variational Hodge conjecture i.e., given a family of smooth projective varieties $\pi:\mathcal{X} \to B$, a special fiber $\mathcal{X}_o$ and a semi-regular subvariety $Z \subset…

Algebraic Geometry · Mathematics 2016-12-05 Ananyo Dan , Inder Kaur

We work over an algebraically closed field of positive characteristic. This paper investigates linear representations of Galois groups arising from wild Galois points on projective hypersurfaces. We prove that these Galois groups lift to…

Algebraic Geometry · Mathematics 2025-09-26 Taro Hayashi , Kashu Ito , Atsuya Nakajima , Keika Shimahara

We show that if $f\colon X \to T$ is a surjective morphism between smooth projective varieties over an algebraically closed field $k$ of characteristic $p>0$ with geometrically integral and non-uniruled generic fiber, then $K_{X/T}$ is…

Algebraic Geometry · Mathematics 2026-05-27 Zsolt Patakfalvi

We study area-minimizing hypersurfaces in singular ambient manifolds whose tangent cones have nonnegative scalar curvature on their regular parts. We prove that the singular set of the hypersurface has codimension at least 3 in our…

Differential Geometry · Mathematics 2024-06-27 Yihan Wang

We employ the formalism of vanishing cycles and perverse sheaves to introduce and study the vanishing cohomology of complex projective hypersurfaces. As a consequence, we give upper bounds for the Betti numbers of projective hypersurfaces,…

Algebraic Geometry · Mathematics 2022-09-15 Laurenţiu Maxim , Laurenţiu Păunescu , Mihai Tibăr

In this survey, we report on progress concerning families of projective curves with fixed number and fixed (topological or analytic) types of singularities. We are, in particular, interested in numerical, universal and asymptotically proper…

Algebraic Geometry · Mathematics 2007-05-23 Gert-Martin Greuel , Christoph Lossen , Eugenii Shustin

We have developed in the past several algorithms with intrinsic complexity bounds for the problem of point finding in real algebraic varieties. Our aim here is to give a comprehensive presentation of the geometrical tools which are…

Algebraic Geometry · Mathematics 2009-11-23 B. Bank , M. Giusti , J. Heintz , M. Safey El Din , E. Schost

Real Legendrian subvarieties are classical objects of differential geometry and classical mechanics and they have been studied since antiquity. However, complex Legendrian subvarieties are much more rigid and have more exceptional…

Algebraic Geometry · Mathematics 2013-05-16 Jarosław Buczyński

Classification theory and the study of projective varieties which are covered by rational curves of minimal degrees naturally leads to the study of families of singular rational curves. Since families of arbitrarily singular curves are hard…

Algebraic Geometry · Mathematics 2007-05-23 Stefan Kebekus