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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.

168,657 papers · 148 categories

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14284155 · May 202619922001200920172026
48 results for strictly nef subsheaf

Projective manifolds with specific bundles are isomorphic to simpler spaces.

problem Characterizing projective manifolds with tangent bundles containing strictly nef subsheaves.
method Analyzing the structure of the tangent bundle and using properties of strictly nef subsheaves.
result Projective manifolds with the described bundles are isomorphic to projective bundles over hyperbolic manifolds or projective spaces.

In this paper, we show that if the tangent bundle of a smooth projective variety is strictly nef, then it is isomorphic to a projective space; if a projective variety XnX^n (n>4)(n>4) has strictly nef Λ2TXΛ^2 TX, then it is isomorphic to Pn\mathbb{P}^n or quadric Qn\mathbb{Q}^n. We also prove that on elliptic curves, strict…

2016-09-22abs ↗pdf ↗

In this paper, we study smooth complex projective varieties XX such that some exterior power rTX\bigwedge^r T_X of the tangent bundle is strictly nef. We prove that such varieties are rationally connected. We also classify the following two cases. If TXT_X is strictly nef, then XX isomorphic to the projective space $\…

2018-01-28abs ↗pdf ↗

The paper studies algebraic fibre spaces with specific properties and proves key results about their structure.

problem Analyzing properties of algebraic fibre spaces with strictly nef relative anti-log canonical divisors.
method Using projective klt pairs and fibration techniques, the paper proves locally constant fibration properties and rational connectedness.
result The fibration is locally constant with rationally connected fibers, and the base is a canonically polarized hyperbolic projective manifold.

The paper proves structures for complex projective varieties with certain tangent bundle properties.

problem Characterizing complex projective varieties based on properties of their tangent bundles.
method Analyzing the positivity of exterior powers of tangent bundles and using étale covers.
result Complex projective varieties with nef exterior powers of tangent bundles are Fano fiber spaces over Abelian varieties.

Study positive characteristic Fano 4-folds with nef tangent bundles.

problem Positive characteristic version of the Campana-Peternell conjecture for Fano 4-folds.
method Analyzes Fano 4-folds with nef tangent bundles in positive characteristic.
result Affirmative answer for Fano 4-folds with Picard number > 1 and nef tangent bundle.

Given a (meromorphic) fibration f:XYf:X\to Y where XX and YY are compact complex manifolds of dimensions nn and mm, we define LfL_f to be the invertible subsheaf of the sheaf of holomorphic mm-forms of XX given by the saturation of fKYf^*K_Y, where KYK_Y is the canonical sheaf of YY. We define the Kodaira dimension…

2002-11-04abs ↗pdf ↗

New proof of LL^\infty estimates for Monge-Ampère and Hessian equations on nef classes.

problem Estimating solutions to Monge-Ampère and Hessian equations on nef classes.
method Applying PDE approach to Kähler manifolds to nef classes.
result New proofs of estimates for Monge-Ampère and Hessian equations.

Fundamental groups of certain Kähler orbifolds have polynomial growth.

problem Understanding the fundamental groups of specific types of orbifolds.
method Analyzing the orbifold fundamental group with respect to the nef anticanonical bundle.
result The orbifold fundamental group has polynomial growth.

Study Miyaoka-Yau inequality for certain projective manifolds.

problem Proving Miyaoka-Yau inequality for specific types of manifolds.
method Using recent work by K.~Zhang and delta-invariant introduced by Fujita and Odaka.
result Established Miyaoka-Yau type inequality for projective manifolds with nef anti-canonical line bundle.

The paper proves inequalities for orbifold second Chern classes in Fujiki's class.

problem Inequalities for orbifold second Chern classes of compact normal analytic varieties.
method Generic nefness theorems for tangent and cotangent sheaves, and an orbifold Bogomolov--Gieseker inequality for mixed polarizations.
result Semipositivity of the orbifold second Chern class for varieties with nef anti-canonical divisor.

The paper studies fundamental groups of compact Kahler varieties with nef anti-canonical bundles.

problem Understanding the fundamental groups of compact Kahler varieties with specific properties.
method Application of geometric analytic theory of Kahler spaces and study of Albanese maps.
result The fundamental group of compact Kahler varieties with nef anti-canonical bundle is almost Abelian.

The paper studies foliations on smooth projective varieties and their properties.

problem Characterizing and understanding foliations on smooth projective varieties.
method Develops a structure theorem for smooth projective varieties with almost nef regular foliations, using a smooth morphism and MRC fibration.
result An almost nef regular foliation on a smooth projective variety can be decomposed into a numerically flat regular foliation and a smooth morphism.

Study of tangent bundle positivity on complex projective varieties.

problem Positivity of the second exterior power of tangent bundles on smooth complex projective varieties.
method Analyzes properties of tangent bundles and uses algebraic geometry techniques.
result Proves that up to a finite cover, the Albanese map is a locally trivial fibration with nef fibers.

The paper proves conditions for solutions of JJ-equation and deformed Hermitian-Yang-Mills equation on holomorphic submersions.

problem Conditions for existence of solutions of JJ-equation and deformed Hermitian-Yang-Mills equation on holomorphic submersions.
method Adiabatic limit technique
result Conditions for existence of solutions of JJ-equation and deformed Hermitian-Yang-Mills equation on holomorphic submersions.

Study the Albanese map for Kähler manifolds with nef anticanonical bundle.

problem Characterize the structure of the Albanese map for Kähler manifolds with nef anticanonical bundle.
method Analyze two cases: general fiber is Calabi-Yau or projective space. Provide proofs for both cases.
result For the case where the general fiber is Calabi-Yau, the manifold itself must be Calabi-Yau.

We introduce a canonical outer vector field on a Poisson manifold, also due independently to A. Weinstein. We view it as a global section of the sheaf of Poisson vector fields modulo the subsheaf of hamiltonian vector fields. We study this outer derivation mostly in the case of holomorphic Poisson manifolds.

1998-02-03abs ↗pdf ↗

The paper establishes inequalities for Chern classes and numbers on polarized manifolds and nef vector bundles.

problem Chern class and number inequalities on polarized manifolds and nef vector bundles.
method Sharp inequalities derived from polarized pairs and nef vector bundles.
result Bounding Chern numbers of nef vector bundles and classifying compact Kähler manifolds.

Paper proves structure of compact Kähler 3-folds with specific bundles.

problem Characterizing compact Kähler 3-folds with nef anti-canonical bundles.
method Minimal Model Program, positivity of direct image sheaves, Q-conic bundles, orbifold vector bundles.
result Compact Kähler 3-folds with nef anti-canonical bundles are essentially one of three types.

The study of projective varieties with nef anticanonical divisors and log terminal singularities.

problem Understanding the structure and properties of projective varieties with specific divisor conditions.
method Analyzing the Albanese map and MRC fibration for klt projective varieties, showing locally constant fibrations and product decompositions.
result Generalization of results for smooth projective varieties to the klt case, including decomposition into rationally connected and projective varieties with trivial canonical divisor.

Let (X,ω)(X,ω) be a compact Kähler manifold of dimension nn, and θθ be a closed smooth real (1,1)(1,1)-form representing a big and nef cohomology class. We introduce a metric dp,p1d_p, p\geq 1, on the finite energy space Ep(X,θ)\mathcal{E}^p(X,θ), making it a complete geodesic metric space.

2018-08-20abs ↗pdf ↗

The paper proves conditions for minimal compact Kähler manifolds with vanishing second Chern class.

problem Conditions for minimal compact Kähler manifolds with vanishing second Chern class.
method Study of the abundance conjecture and associated Iitaka fibrations.
result For a minimal compact Kähler manifold, the second Chern class vanishes if and only if the cotangent bundle is nef and the canonical bundle has numerical dimension 0 or 1.

The paper shows how compact Kähler manifolds with a special bundle can be broken down into simpler parts.

problem Understanding compact Kähler manifolds with a specific type of anti-canonical bundle.
method Introduced a new approach to extend a strategy from smooth projective varieties to singular Kähler spaces, using a flatness criterion for pseudo-effective sheaves.
result Compact Kähler manifolds with a nef anti-canonical bundle admit a locally trivial fibration with rational connected fibers and a Calabi-Yau base.

The paper classifies certain singular projective varieties with specific properties.

problem Classifying projective klt pairs with nef anti-log canonical divisors.
method Establishes a structure theorem using locally trivial rationally connected fibrations.
result Projective klt pairs can be decomposed into rationally connected and Calabi-Yau varieties.

Study confirms conjecture on Hermitian manifolds with bounded mass.

problem Morse-type integrals in nef (1,1) classes on compact Hermitian manifolds with bounded mass.
method Analyzes conjecture using bounded mass property on compact Hermitian manifolds.
result Confirms Demailly-Păun and Tosatti-Weinkove's conjectures.

The paper establishes lower bounds on Yang-Mills functionals for fibrations.

problem Analyzing the stability and nefness of direct image sheaves in fibrations.
method Generalizing mean curvature and Harder-Narasimhan filtrations to arbitrary polarized fibrations.
result Optimal lower bounds on fibered Yang-Mills functionals in terms of direct image sheaves.

Estimates Lelong numbers of Monge-Ampère products for Kähler manifolds.

problem Estimating Lelong numbers of Monge-Ampère products on Kähler manifolds.
method Analyzes generalized Monge-Ampère products and applies estimates to Chern and Segre currents of pseudoeffective vector bundles.
result Generalizes a recent result about pseudoeffective vector bundles and their nefness.

Let M be a compact, holomorphically symplectic Kahler manifold, and ηη a (1,1)-current which is nef (a limit of Kahler forms). Assume that the cohomology class of ηη is parabolic, that is, its top power vanishes. We prove that all Lelong sets of ηη are coisotropic. When M is generic, this is used to show that all Le…

2009-07-24abs ↗pdf ↗

Paper proves Hermitian-Yang-Mills metrics for stable Kähler bundles.

problem Existence of Hermitian-Yang-Mills metrics for Kähler vector bundles.
method Analyzes slope polystability and uses Kähler currents with singularities.
result Validates existence of Hermitian-Yang-Mills metrics for stable bundles and nef-big currents.

Two types of nonvanishing results are presented for compact Kähler varieties.

problem Deriving geometric consequences from numerical information in Kähler geometry.
method Analyzing non-uniruled varieties and hyperkähler manifolds to establish nonvanishing results for adjoint and nef bundles.
result Strong abundance-type results are obtained in dimension 4.