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This is the first of a series of papers on sheaf theory on smooth and topological stacks and its applications. The main result of the present paper is the characterization of the twisted (by a closed integral three-form) de Rham complex on…

K-Theory and Homology · Mathematics 2014-10-01 Ulrich Bunke , Thomas Schick , Markus Spitzweck

We show that every sheaf on the site of smooth manifolds with values in a stable (infinity,1)-category (like spectra or chain complexes) gives rise to a differential cohomology diagram and a homotopy formula, which are common features of…

K-Theory and Homology · Mathematics 2013-11-15 Ulrich Bunke , Thomas Nikolaus , Michael Völkl

Let $\mathcal{F}$ be a coherent sheaf on a complex variety $X$ that has a locally free resolution $E^{\bullet}$. In [19], the authors constructed a pseudomeromorphic current whose support is contained in $supp(E^{\bullet})$ that represents…

Algebraic Geometry · Mathematics 2024-10-17 Zhaobo Tom Han

We give a moduli interpretation of the outer automorphism group Out of a finite dimensional algebra similar to that of the Picard group of a scheme. We deduce that Out^0 is invariant under derived and stable equivalences. This allows us to…

Representation Theory · Mathematics 2010-08-12 Raphael Rouquier

Improved local and global versions of the effective Nullstellensatz for ideal sheaves on non-singular complex varieties are obtained, based on a new invariant motivated by the notion of finite type from the theory of several complex…

Algebraic Geometry · Mathematics 2007-05-23 Gordon Heier

We describe a differential graded Lie algebra controlling infinitesimal deformations of triples $(X,\mathcal{F},\sigma)$, where $\mathcal{F}$ is a coherent sheaf on a smooth variety $X$ over a field of characteristic 0 and $\sigma\in…

Algebraic Geometry · Mathematics 2026-02-05 Donatella Iacono , Marco Manetti

A singular point of a smooth map F: M -> N of manifolds is a point in M at which the rank of the differential dF is less than the minimum of dimensions of M and N. The classical invariant of the set S of singular points of F of a given type…

Geometric Topology · Mathematics 2015-03-14 Rustam Sadykov

Let f : X -> Y be a morphism between normal complex varieties, and assume that Y is Kawamata log terminal. Given any differential form, defined on the smooth locus of Y, we construct a "pull-back form" on X. The pull-back map obtained by…

Algebraic Geometry · Mathematics 2013-07-23 Stefan Kebekus

Let $f : X \rightarrow Y$ be a generically smooth nonconstant morphism between irreducible projective curves, defined over an algebraically closed field, which is \'etale on an open subset of $Y$ that contains both the singular locus of $Y$…

Algebraic Geometry · Mathematics 2024-01-04 Indranil Biswas , Manish Kumar , A. J. Parameswaran

Given an open-closed decomposition of the stratifying poset, we construct a new semi-orthogonal decomposition of the $\infty$-category of constructible sheaves on a stratified space admitting an exit-path $\infty$-category. From this we…

K-Theory and Homology · Mathematics 2026-02-24 Qingyuan Bai , Peter J. Haine

The paper begins by overviewing the basic facts on geometric exceptional collections. Then, we derive, for any coherent sheaf $\cF$ on a smooth projective variety with a geometric collection, two spectral sequences: the first one abuts to…

Algebraic Geometry · Mathematics 2019-05-01 L. Costa , R. M. Miró-Roig

Let $X$ be a smooth, irreducible, projective algebraic surface, and let $\alpha \in \mathbb{Q}[m]_{>0}$ be a polynomial. In this paper, we determine topological and geometric properties of the moduli space of $\alpha$-stable coherent…

Algebraic Geometry · Mathematics 2026-03-23 L. Costa , I. Macías Tarrío , L. Roa-Leguizamón

We prove that the singular support of an element in the derived category of sheaves is $\gamma$-coisotropic, a notion defined in [Vit22]. We prove that this implies that it is involutive in the sense of Kashiwara-Schapira, but being…

Symplectic Geometry · Mathematics 2023-09-18 Stéphane Guillermou , Claude Viterbo

We continue the development of the study of the equisingularity of isolated singularities, in the determinantal case. This version of the paper includes a substantial amount of new material (76% larger). The new material introduces the idea…

Complex Variables · Mathematics 2016-01-05 Terence Gaffney , Antoni Rangachev

In this work more questions arise than answers given, for which of course we do not apologize. The core of this paper is concerned with the construction of a ``constant'' t-structure on the bounded derived category of coherent sheaves…

Algebraic Geometry · Mathematics 2007-05-23 Dan Abramovich , Alexander Polishchuk

A reduced divisor on a nonsingular variety defines the sheaf of logarithmic 1-forms. We introduce a certain coherent sheaf whose double dual coincides with this sheaf. It has some nice properties, for example, the residue exact sequence…

Algebraic Geometry · Mathematics 2007-05-23 Igor V. Dolgachev

The spectral side of the (conjectural) Betti geometric Langlands correspondence concerns sheaves on the character stack of an algebraic curve; in particular, the categories in question are manifestly invariant under deformations of the…

Representation Theory · Mathematics 2023-01-13 David Nadler , Vivek Shende

We study the following generalization of singularity categories. Let X be a quasi-projective Gorenstein scheme with isolated singularities and A a non-commutative resolution of singularities of X in the sense of Van den Bergh. We introduce…

Representation Theory · Mathematics 2017-09-15 Martin Kalck

On conformal manifolds of even dimension $n\geq 4$ we construct a family of new conformally invariant differential complexes. Each bundle in each of these complexes appears either in the de Rham complex or in its dual. Each of the new…

Differential Geometry · Mathematics 2007-05-23 Thomas Branson , A. Rod Gover

In this paper, we introduce new enumerative invariants of curves on Calabi-Yau 3-folds via certain stable objects in the derived category of coherent sheaves. We introduce the notion of limit stability on the category of perverse coherent…

Algebraic Geometry · Mathematics 2019-12-19 Yukinobu Toda