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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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2457 · Sep 201919922001200920172026
48 results for nef divisors

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 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.

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.

In this paper, we study a projective klt pair (X,Δ)(X, Δ) with the nef anti-log canonical divisor (KX+Δ)-(K_X+Δ) and its maximally rationally connected fibration ψ:XYψ: X \dashrightarrow Y. We prove that the numerical dimension of the anti-log canonical divisor (KX+Δ)-(K_X+Δ) on XX coincides with that of the anti-log canonical div…

2019-10-15abs ↗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 extends intersection theory for b-divisors, proving monotonicity and volume inequalities.

problem Intersection theory for b-divisors and monotonicity of intersection products.
method Developed general intersection theory of nef b-divisors, defined restricted volume, proved monotonicity.
result Proved quantitative monotonicity of intersection product and new volume inequalities.

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.

In this paper, we show that the canonical divisor of a smooth toroidal compactification of a complex hyperbolic manifold must be nef if the dimension is greater or equal to three. Moreover, if n3n\geq 3 we show that the numerical dimension of the canonical divisor of a smooth nn-dimensional compactification is always …

2015-02-22abs ↗pdf ↗

The Miyaoka-Yau inequality is proven for certain singular varieties with big canonical or anticanonical divisors.

problem Establishing the Miyaoka-Yau inequality for singular varieties with specific divisors.
method Defining the non-pluripolar product and establishing the Bogomolov-Gieseker type inequality for Higgs sheaves; investigating second Chern class inequalities.
result Proven the Miyaoka-Yau inequality for projective klt varieties with big canonical or anticanonical divisors.

The paper classifies minimal projective varieties satisfying a specific equality.

problem Classifying minimal projective varieties with a specific equality.
method Established a structure theorem for minimal projective klt varieties satisfying Miyaoka's equality.
result Minimal projective klt varieties with Miyaoka's equality have semi-ample canonical divisors and specific Kodaira dimensions.

We generalize the maximal time existence of Kähler-Ricci flow in Tian-Zhang and Song-Tian to conical case. Furthermore, if the twisted canonical bundle KM+(1β)[D]K_{M}+(1-β)[D] is big or big and nef, we can expect more on the limit behaviors of such conical Kähler-Ricci flow. Moreover, the results still hold for simple normal …

2014-11-26abs ↗pdf ↗

Fix a K3 lattice ΛΛ of rank two and LΛL\inΛ a big and nef divisor that is positive enough. We prove that the generic ΛΛ-polarised K3 surface has an integral nodal rational curve in the linear system L|L|, in particular strengthening previous work of the first named author. The technique is by degeneration, and also …

2019-07-02abs ↗pdf ↗

The goal of this paper is to study the geometry of cusped complex hyperbolic manifolds through their compactifications. We characterize toroidal compactifications with non-nef canonical divisor. We derive effective very ampleness results for toroidal compactifications of finite volume complex hyperbolic manifolds. We e…

2012-12-03abs ↗pdf ↗

Let O(D)\mathcal{O}(D) be an equivariant line bundle which is big and nef on a complex projective nonsingular toric variety XX. Given a continuous toric metric \|\cdot\| on O(D)\mathcal{O}(D), we define the energy at equilibrium of (X,φDˉ)(X,φ_{\bar{D}}) where φDˉφ_{\bar{D}} is the weight of the metrized toric divisor $\bar{D…

2016-03-07abs ↗pdf ↗

Study on Kähler-Einstein metrics on quasi-projective manifolds.

problem Constructing and analyzing Kähler-Einstein metrics on quasi-projective manifolds.
method Utilizes singular Kähler-Einstein metrics and conic Kähler-Einstein metrics of negative curvature.
result Established the weak convergence of conic Kähler-Einstein metrics to singular Kähler-Einstein metrics.

Criterion for projectivisation on klt spaces, characterizing quotients and stability.

problem Characterizing finite quotients of projective spaces and Abelian varieties.
method Criterion based on reflexive sheaves and stability conditions.
result Characterization of finite quotients using Q\mathbb{Q}-Chern class inequalities and stability condition.

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.

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 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.

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.

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.

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.

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.

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.