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We prove a symmetric version of B\'ezout's theorem. More precisely, we show that the symmetric orbit type of a transverse intersection of complex symmetric hypersurfaces in projective space is determined by the degrees. In the projective…

Algebraic Geometry · Mathematics 2024-10-01 Samuel Lidz , Zachary Lihn , Adam Melrod

We extend the notions of complete intersection dimension and lower complete intersection dimension to the category of complexes with finite homology and verify basic properties analogous to those holding for modules. We also discuss the…

Commutative Algebra · Mathematics 2007-05-23 Sean Sather-Wagstaff

We describe an analogue of the notion of a perverse sheaf in the setting of the derived category of coherent sheaves on an algebraic stack. Under strong additional assumptions the construction of coherent "intersection cohomology" complexes…

Algebraic Geometry · Mathematics 2021-02-04 Dmitry Arinkin , Roman Bezrukavnikov

We consider a hyperplane arrangement in $\mathbb{C}^n$ defined over $\mathbb{R}$, and the associated natural stratification of $\mathbb{C}^n$. The category of perverse sheaves smooth with respect to this stratification was described by…

Representation Theory · Mathematics 2020-11-17 Asilata Bapat

This paper presents a combinatorial analog of topological complexity for finite spaces. We demonstrate that this coincides with the genuine topological complexity of the original finite space, and constitutes an upper bound for the…

Combinatorics · Mathematics 2019-03-22 Kohei Tanaka

In this paper we illustrate an algorithmic procedure which allows to build projective wonderful models for the complement of a toric arrangement in a n-dimensional algebraic torus T. The main step of the construction is a combinatorial…

Algebraic Geometry · Mathematics 2016-09-01 Corrado De Concini , Giovanni Gaiffi

Let $f:\CN \rightarrow \C $ be a polynomial, which is transversal (or regular) at infinity. Let $\U=\CN\setminus f^{-1}(0)$ be the corresponding affine hypersurface complement. By using the peripheral complex associated to $f$, we give…

Algebraic Topology · Mathematics 2016-01-20 Yongqiang Liu , Laurentiu Maxim

The real intersection cohomology of a toric variety is described in a purely combinatorial way using methods of elementary commutative algebra only. We define, for arbitrary fans, the notion of a ``minimal extension sheaf'' on the fan as an…

Algebraic Geometry · Mathematics 2009-10-31 Karl-Heinz Fieseler

We study the arithmetic of complete intersections in projective space over number fields. Our main results include arithmetic Torelli theorems and versions of the Shafarevich conjecture, as proved for curves and abelian varieties by…

Algebraic Geometry · Mathematics 2016-08-02 Ariyan Javanpeykar , Daniel Loughran

We introduce techniques of Suslin, Voevodsky, and others into the study of singular varieties. Our approach is modeled after Goresky-MacPherson intersection homology. We provide a formulation of perversity cycle spaces leading to perversity…

K-Theory and Homology · Mathematics 2019-02-20 Eric M. Friedlander , Joseph Ross

We describe a class of affine toric varieties $V$ that are set-theoretically minimally defined by codim $V+1$ binomial equations over fields of any characteristic.

Algebraic Geometry · Mathematics 2007-05-23 Margherita Barile

We show that the variable cohomology of a general complete intersection of quadrics can be identified with the intersection cohomology of a double covering. As a consequence, we show that the middle cohomology of a general complete…

Algebraic Geometry · Mathematics 2023-05-24 Jan Nagel

We define and study twisted Alexander-type invariants of complex hypersurface complements. We investigate torsion properties for the twisted Alexander modules and extend classical local-to-global divisibility results to the twisted setting.…

Algebraic Topology · Mathematics 2016-05-24 Laurentiu Maxim , Kaiho Tommy Wong

Let X be a smooth toric variety stratified by the torus action. This paper is a presentation of a description of the category Perv_X of perverse sheaves on X relatively to the fixed stratification. We define a category of representations of…

Algebraic Geometry · Mathematics 2010-03-17 Delphine Dupont

Let $A$ be a coherent algebra and $B$ be a finite-dimensional Gorenstein algebra over a field $k$. We describe finitely presented Gorenstein projective $A\otimes_k B$-modules in terms of their underlying onesided modules. Moreover, if the…

Representation Theory · Mathematics 2016-02-02 Dawei Shen

Let X be a scheme of finite type over a Noetherian base scheme S admitting a dualizing complex, and let U be an open subset whose complement has codimension at least 2. We extend the Deligne-Bezrukavnikov theory of perverse coherent sheaves…

Representation Theory · Mathematics 2017-01-03 Pramod N. Achar , Daniel S. Sage

We study homological properties of a locally complete intersection ring by importing facts from homological algebra over exterior algebras. One application is showing that the thick subcategories of the bounded derived category of a locally…

Commutative Algebra · Mathematics 2021-09-21 Jian Liu , Josh Pollitz

For a particular class of pseudo manifolds, we show that the intersection cohomology groups for any perversity may be naturally represented by extended weighted $L^2$ harmonic forms for a complete metric on the regular stratum with respect…

Geometric Topology · Mathematics 2017-01-12 E. Hunsicker

We generalized the construction of deformations of affine toric varieties of K. Altmann and our previous construction of deformations of weak Fano toric varieties to the case of arbitrary toric varieties by introducing the notion of…

Algebraic Geometry · Mathematics 2011-02-25 Anvar Mavlyutov

The anticanonical complex generalizes the Fano polytope from toric geometry and has been used to study Fano varieties with torus action so far. We work out the case of complete intersections in toric varieties defined by non-degenerate…

Algebraic Geometry · Mathematics 2025-07-01 Juergen Hausen , Christian Mauz , Milena Wrobel