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19
Integral transforms and Drinfeld centers in derived algebraic geometry
"... Compact objects are as necessary to this subject as air to breathe. R.W. Thomason to A. Neeman, [N3] Abstract. We study natural algebraic operations on categories arising in algebraic geometry and its homotopytheoretic generalization, derived algebraic geometry. We work with a broad class of derive ..."
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Compact objects are as necessary to this subject as air to breathe. R.W. Thomason to A. Neeman, [N3] Abstract. We study natural algebraic operations on categories arising in algebraic geometry and its homotopytheoretic generalization, derived algebraic geometry. We work with a broad class of derived stacks which we call stacks with air. The class of stacks with air includes in particular all quasicompact, separated derived schemes and (in characteristic zero) all quotients of quasiprojective or smooth derived schemes by affine algebraic groups, and is closed under derived fiber products. We show that the (enriched) derived categories of quasicoherent sheaves on stacks with air behave well under algebraic and geometric operations. Namely, we identify the derived category of a fiber product with the tensor product of the derived categories of the factors. We also identify functors between derived categories of sheaves with integral transforms (providing a generalization of a theorem of Toën [To1] for ordinary schemes over a ring). As a first application, for a stack Y with air, we calculate the Drinfeld center (or synonymously,
Moduli of objects in dgcategories
, 2006
"... To any dgcategory T (over some base ring k), we define a D −stack MT in the sense of [HAGII], classifying certain T opdgmodules. When T is saturated, MT classifies compact objects in the triangulated category [T] associated to T. The main result of this work states that under certain finiteness ..."
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To any dgcategory T (over some base ring k), we define a D −stack MT in the sense of [HAGII], classifying certain T opdgmodules. When T is saturated, MT classifies compact objects in the triangulated category [T] associated to T. The main result of this work states that under certain finiteness conditions on T (e.g. if it is saturated) the D −stack MT is locally geometric (i.e. union of open and geometric substacks). As a consequence we prove the algebraicity of the group of autoequivalences of saturated dgcategories. We also obtain the existence of reasonable moduli for perfect complexes on a smooth and proper scheme, as
Twisted differential String and Fivebrane structures
, 2009
"... Abelian differential generalized cohomology as developed by Hopkins and Singer has been shown by Freed to formalize the global description of anomaly cancellation problems in String theory, such as notably the GreenSchwarz mechanism. On the other hand, this mechanism, as well as the FreedWitten an ..."
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Cited by 7 (7 self)
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Abelian differential generalized cohomology as developed by Hopkins and Singer has been shown by Freed to formalize the global description of anomaly cancellation problems in String theory, such as notably the GreenSchwarz mechanism. On the other hand, this mechanism, as well as the FreedWitten anomaly cancellation, are fundamentally governed by the cohomology classes represented by the relevant nonabelian O(n) and U(n)principal bundles underlying the tangent and the gauge bundle on target space. In this article we unify the picture by describing nonabelian differential cohomology and twisted nonabelian differential cohomology and apply it to these situations. We demonstrate that the FreedWitten mechanism for the Bfield, the GreenSchwarz mechanism for the H3field, as well as its magnetic dual version for the H7field define cocycles in twisted nonabelian differential cohomology that may be addressed, respectively, as twisted Spin(n), twisted String(n) and twisted Fivebrane(n)structures on target space, where the twist in each case is provided by the obstruction to lifting the gauge bundle through a higher connected cover of U(n). We work out the (nonabelian) L∞algebra valued connection data provided by the differential refinements of these twisted cocycles and demonstrate that this reproduces locally the differential form data with the twisted Bianchi identities as known from the
The theory of the invariants obtained from the moduli stacks of stable objects on a smooth polarized surface
, 2002
"... ..."
A SURVEY OF (∞, 1)CATEGORIES
, 2006
"... Abstract. In this paper we give a summary of the comparisons between different definitions of socalled (∞,1)categories, which are considered to be models for ∞categories whose nmorphisms are all invertible for n> 1. They are also, from the viewpoint of homotopy theory, models for the homotopy th ..."
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Abstract. In this paper we give a summary of the comparisons between different definitions of socalled (∞,1)categories, which are considered to be models for ∞categories whose nmorphisms are all invertible for n> 1. They are also, from the viewpoint of homotopy theory, models for the homotopy theory of homotopy theories. The four different structures, all of which are equivalent, are simplicial categories, Segal categories, complete Segal spaces, and quasicategories. 1.
DIFFERENTIAL CHARACTERS AS STACKS AND PREQUANTIZATION
, 2008
"... We generalize geometric prequantization of symplectic manifolds to differentiable stacks. Our approach is atlasindependent and provides a bijection between isomorphism classes of principal S 1bundles (with or without connections) and second cohomology groups of certain chain complexes. ..."
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We generalize geometric prequantization of symplectic manifolds to differentiable stacks. Our approach is atlasindependent and provides a bijection between isomorphism classes of principal S 1bundles (with or without connections) and second cohomology groups of certain chain complexes.
Nonabelian homotopical cohomology,
"... higher fiber bundles with connection, and their σmodel QFTs ..."
Nonabelian homotopical cohomology,
"... higher fiber bundles with connection, and their σmodel QFTs ..."
PRESENTING HIGHER STACKS AS SIMPLICIAL SCHEMES J.P.PRIDHAM
, 905
"... Abstract. We show that an ngeometric stack may be regarded as a special kind of simplicial scheme, namely a Duskin nhypergroupoid in affine schemes, where surjectivity is defined in terms of covering maps, yielding Artin nstacks, DeligneMumford nstacks and nschemes as the notion of covering va ..."
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Abstract. We show that an ngeometric stack may be regarded as a special kind of simplicial scheme, namely a Duskin nhypergroupoid in affine schemes, where surjectivity is defined in terms of covering maps, yielding Artin nstacks, DeligneMumford nstacks and nschemes as the notion of covering varies. This formulation adapts to most HAG contexts, so in particular works for derived nstacks (replacing rings with simplicial rings). We exploit this to describe quasicoherent sheaves and complexes on these stacks, and to draw comparisons with Kontsevich’s dgschemes. As an application, we show how the
Holomorphic generating functions for invariants
, 2006
"... counting coherent sheaves on Calabi–Yau 3folds ..."