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A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,742 papers · 148 categories

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48 results for normal sheaf

PolyNSD improves Neural Sheaf Diffusion with polynomial operators and spectral rescaling.

problem Limitations of common Neural Sheaf Diffusion implementations, including scalability and stability issues.
method Introduces Polynomial Neural Sheaf Diffusion (PolyNSD) with a degree-K polynomial propagation operator and spectral rescaling.
result PolyNSD achieves state-of-the-art results on both homophilic and heterophilic benchmarks with reduced runtime and memory requirements.

We introduce a weak concept of Morita equivalence, in the birational context, for Poisson modules on complex normal Poisson projective varieties. We show that Poisson modules, on projective varieties with mild singularities, are either rationally Morita equivalent to a flat partial holomorphic sheaf, or a sheaf with a …

2019-08-06abs ↗pdf ↗

The paper shows how certain complex projective varieties can be broken down into simpler types.

problem Understanding the structure of complex projective varieties with pseudo-effective tangent sheaves.
method Developed a theory of pseudo-effective sheaves and applied the minimal model program.
result Projective klt varieties with pseudo-effective tangent sheaves can be decomposed into Fano varieties and Q-abelian varieties.

Study excess logarithmic residues for foliations to bound invariant hypersurfaces and test log canonicity.

problem Bounding invariant hypersurfaces and testing log canonicity of singularities.
method Introduce excess logarithmic residues, prove residue formula, derive Poincaré-type bound, and use them to recover log discrepancies.
result Componentwise logarithmic residues of a lifted foliation along the exceptional divisor recover log discrepancies of singularities.

Let SS be a smooth projective variety and ΔΔ a simple normal crossing Q\mathbb{Q}-divisor with coefficients in (0,1](0,1]. For any ample Q\mathbb{Q}-line bundle LL over SS, we denote by E(L)\mathscr{E}(L) the extension sheaf of the orbifold tangent sheaf TS(log(Δ))T_S(-\log(Δ)) by the structure sheaf OS\mathcal{O}_S with the …

2018-03-05abs ↗pdf ↗

On a Weinstein manifold, we define a constructible co/sheaf of categories on the skeleton. The construction works with arbitrary coefficients, and depends only on the homotopy class of a section of the Lagrangian Grassmannian of the stable symplectic normal bundle. The definition is as follows. Take any, possibly high …

2017-07-24abs ↗pdf ↗

In the framework of Abstract Differential Geometry, we show that to a given principal sheaf and a representation of its stuctural sheaf in AnA^n, where A is a sheaf of associative, commutative, unital algebras (over R or C), we associate a vector sheaf. Moreover, under some natural assumptions on the compatibility of t…

1998-10-13abs ↗pdf ↗

An analytic approach and description are presented for the moduli cotangent sheaf for suitable stable curve families including noded fibers. For sections of the square of the relative dualizing sheaf, the residue map at a node gives rise to an exact sequence. The residue kernel defines the vanishing residue subsheaf. F…

2012-04-17abs ↗pdf ↗

HSSE framework embeds single-cell RNA-seq data at multiple scales.

problem Capturing heterogeneous local structure in single-cell RNA-seq data.
method Hierarchical sheaf spectral embedding (HSSE) framework.
result HSSE achieves competitive or improved performance in single-cell RNA-seq data representation learning.

We study the cohomology theory of sheaf complexes for open embeddings of topological spaces and related subjects. The theory is situated in the intersection of the general Cech theory and the theory of derived categories. That is to say, on the one hand the cohomology is described as the relative cohomology of the sect…

2018-10-15abs ↗pdf ↗

In this paper, we study the asymptotic behavior of the Hermitian-Yang-Mills flow on a reflexive sheaf. We prove that the limiting reflexive sheaf is isomorphic to the double dual of the graded sheaf associated to the Harder-Narasimhan-Seshadri filtration, this answers a question by Bando and Siu.

2017-04-24abs ↗pdf ↗

Investigates admissible metrics on compact Kähler varieties and their stability.

problem Existence of admissible metrics on compact Kähler varieties and their stability.
method Analyzes admissible Hermitian metrics and Hermitian-Yang-Mills metrics on slope stable coherent sheaves.
result Existence of admissible metrics and Hermitian-Yang-Mills metrics under certain conditions.

Study deformations of compact Calabi-Yau conifolds with singularities.

problem Understanding deformations of compact Calabi-Yau conifolds with singularities.
method Analyzes the obstructions and local triviality of deformations under specific topological and geometric hypotheses.
result Obstruction to deformations concentrates at singularities, generalizing previous results.

Given a smooth GG-vector bundle EME \to M with a connection \nabla, we propose the construction of a sheaf of vertex algebras Ech(E,)\mathcal{E}^{ch(E,\nabla)}, which we call a \textit{chiral vector bundle}. Ech(E,)\mathcal{E}^{ch(E,\nabla)} contains as subsheaves the sheaf of superalgebras ΩΓ(SEΛE)Ω\otimes Γ(SE \otimes ΛE) and the…

2010-04-19abs ↗pdf ↗

Study exact Lagrangian cobordisms in cotangent bundles, proving bounds on sheaf interleaving distance and shadow distance.

problem Understanding Lagrangian cobordisms and their properties in cotangent bundles.
method Use microlocal theory of sheaves, sheaf quantization, and cone decompositions.
result Interleaving distance of sheaves is bounded by the shadow distance of the cobordism.

Study projective KLT varieties with projectively flat cotangent sheaves.

problem Uniformisation problems on projective varieties with klt singularities.
method Generalising Jahnke-Radloff's work, study torus quotients and varieties with semistable cotangent sheaves and extremal Chern classes.
result Torus quotients are the only klt varieties with semistable cotangent sheaves and extremal Chern classes.

An important part of the classical theory of real or complex manifolds is the theory of (smooth, real analytic or complex analytic) vector bundles. With any vector bundle over a manifold (M,F) the sheaf of its (smooth, real analytic or complex analytic) sections is associated which is a locally free sheaf of F-modules,…

2011-10-18abs ↗pdf ↗

Study jets of flat partial connections in foliations.

problem Characterize and understand flat partial connections in foliations.
method Define and apply jets to flat partial connections in smooth foliations and locally free sheaves, focusing on codimension one and arbitrary codimension foliations.
result Define and apply jets to characterize transversely affine and projective structures in foliations.

We study the geodesics problem in Heisenberg group H (case SR and riemannian). The sheaf of infinitesimal automorphisms of the (2n,2n+1) distribution D over H is an infinite, transitive Lie algebra sheaf.

2005-07-04abs ↗pdf ↗

The paper proves a theorem and characterizes connections over normal varieties.

problem The study addresses the stability and connections over normal varieties.
method The authors prove a complete version of the Donaldson-Uhlenbeck-Yau theorem and use it to show the polystability of reflexive sheaves.
result An admissible Hermitian-Yang-Mills connection defines a polystable reflexive sheaf and gives a lower bound for discriminants.

Let MM be a Riemannian manifold. For pMp\in M, the tensor algebra of the negative part of the (complex) affinization of the tangent space of MM at pp has a natural structure of a meromorphic open-string vertex algebra. These meromorphic open-string vertex algebras form a vector bundle over MM with a connection. We …

2012-05-14abs ↗pdf ↗

We show that the function sheaf of a Z2n\mathbb{Z}_2^n-manifold is a nuclear Fréchet sheaf of Z2n\mathbb{Z}_2^n-graded Z2n\mathbb{Z}_2^n-commutative associative unital algebras. Further, we prove that the components of the pullback sheaf morphism of a Z2n\mathbb{Z}_2^n-morphism are all continuous. These results are essenti…

2018-07-31abs ↗pdf ↗

For a stratified symplectic space, a suitable concept of stratified Kaehler polarization, defined in terms of an appropriate Lie-Rinehart algebra, encapsulates Kaehler polarizations on the strata and the behaviour of the polarizations across the strata and leads to the notion of stratified Kaehler space. This notion es…

2001-04-23abs ↗pdf ↗

Given a CC^\infty real manifold XX and CXm\mathcal{C}^m_X its sheaf of mm-times differentiable real-valued functions, we prove that the sheaf DXm,r\mathcal{D}^{m, r}_X of differential operators of order m\leq m with coefficient functions of class CrC^r can be obtained in terms of the sheaf $\mathcal{H}om_{\mathbb{R}_X}…

2013-02-22abs ↗pdf ↗

The paper addresses deformations of Kähler spaces with vanishing first Chern class.

problem Deformations of Kähler spaces with specific properties.
method Analyzes locally trivial deformation spaces and uses cohomological vanishing conditions.
result Shows that under certain conditions, deformations of Kähler spaces are projective varieties.

Logarithmic connections on principal bundles over normal varieties are studied.

problem Existence and properties of logarithmic connections on principal bundles over normal varieties.
method Introducing logarithmic connections, showing equivalence to covariant derivatives, and proving existence conditions.
result Existence of logarithmic connections on principal bundles over normal varieties is equivalent to certain conditions on the associated vector bundles and adjoint bundles.

Paper studies convergence of Yang-Mills-Higgs flow on Kähler manifolds.

problem Analyzing convergence of Yang-Mills-Higgs flow for twisted Higgs pairs.
method Proves convergence to a reflexive twisted Higgs sheaf outside a closed subset.
result Limiting twisted Higgs sheaf is isomorphic to the double dual of graded twisted Higgs sheaves.

The main goal of this paper is to prove the polystability of the logarithmic tangent sheaf TX(D)\mathscr T_X(-D) of a log canonical pair (X,D)(X,D) whose canonical bundle KX+DK_X+D is ample, generalizing in a significant way a theorem of Enoki. We apply this result and the techniques involved in its proof to get a version of t…

2015-02-12abs ↗pdf ↗

In this paper, we study semistable Higgs sheaves over compact Kähler manifolds, we prove that there is an approximate admissible Hermitian-Einstein structure on a semi-stable reflexive Higgs sheaf and consequently, the Bogomolove type inequality holds on a semi-stable reflexive Higgs sheaf.

2016-01-05abs ↗pdf ↗

We construct master spaces for oriented torsion free sheaves coupled with morphisms into a fixed reference sheaf. These spaces are projective varieties endowed with a natural $\C^*$-action. The fixed point set of this action contains the moduli space of semistable oriented torsion free sheaves and the quot scheme assoc…

1996-07-17abs ↗pdf ↗

Given a Heegaard splitting of a three-manifold Y, we consider the SL(2,C) character variety of the Heegaard surface, and two complex Lagrangians associated to the handlebodies. We focus on the smooth open subset corresponding to irreducible representations. On that subset, the intersection of the Lagrangians is an orie…

2017-08-01abs ↗pdf ↗