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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.

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48 results for log canonical

Counterexample disproves log canonical Beauville--Bogomolov decomposition.

problem Disproving the log canonical Beauville--Bogomolov decomposition.
method Constructing a specific log canonical, K-trivial variety with non-birational fibers.
result Provides a counterexample to the Beauville--Bogomolov decomposition in the log canonical setting.

Constructs Kahler-Einstein metrics near isolated log canonical singularities.

problem Constructing metrics near singularities in complex geometry.
method Constructs Kahler-Einstein metrics with negative scalar curvature near isolated log canonical singularities.
result Metrics are complete near the singularity if the underlying space has complex dimension 2 or if the singularity is smoothable.

We establish the existence of the K"ahler-Ricci flow on projective varieties with log canonical singularities. This generalizes some of the existence results of Song-Tian \cite{ST3} in case of projective varieties with klt singularities. We also prove that the normalized K"ahler-Ricci flow will converge to the \ka-Eins…

2019-06-11abs ↗pdf ↗

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.

Evaluation of the marginal likelihood plays an important role in model selection problems. The widely applicable Bayesian information criterion (WBIC) and singular Bayesian information criterion (sBIC) give approximations to the log marginal likelihood, which can be applied to both regular and singular models. When the…

2019-06-04abs ↗pdf ↗

We compute the log canonical thresholds of non-negatively curved singular hermitian metrics on ample linearized line bundles on bi-equivariant group compactifications of complex reductive groups. To this end, we associate to any such metric a convex function whose asymptotic behavior determines the log canonical thresh…

2015-10-17abs ↗pdf ↗

Study shows polystability of tangent and canonical sheaves on Kähler-Einstein log Fano pairs.

problem Stability of tangent and canonical sheaves on Kähler-Einstein log Fano pairs.
method Analysis of adapted tangent and canonical sheaves under singular Kähler-Einstein metrics.
result Adapted tangent and canonical sheaves are polystable.

The paper extends deformation theory to Calabi-Yau varieties with isolated log canonical singularities.

problem Deformation theory of Calabi-Yau varieties with log canonical singularities.
method Study of higher Du Bois and rational singularities, focusing on 0-liminal singularities.
result Existence of first order smoothings for isolated 0-liminal hypersurface singularities.

Analyzes structure of log smooth pairs when equality holds in Bogomolov-Gieseker inequality.

problem Analyzing log smooth pairs under equality in Bogomolov-Gieseker inequality.
method Examines structure when equality holds in the Bogomolov-Gieseker inequality for semistable logarithmic tangent bundle and canonical extension sheaf.
result Provides insights into the structure of log smooth pairs under specific conditions.

Holomorphic vector fields and anti-canonical divisors on complex manifolds are studied.

problem Existence of non-trivial holomorphic vector fields on compact complex manifolds.
method Vanishing result for measure preserving holomorphic vector fields, Gibbs stability, and log terminal singularities.
result No non-trivial holomorphic vector fields on compact complex manifolds with big anti-canonical line bundle.

Sharp inequalities for weighted log canonical thresholds derived.

problem Understanding weighted log canonical thresholds in complex analysis.
method Combining integrability estimates, complex line restrictions, and pluripotential theory.
result Uniform control of difference quotients and explicit lower bounds derived.

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.

We study global log canonical thresholds of cubic surfaces with canonical singularities, and we prove the existence of a Kahler-Einstein metric on two singular cubic surfaces.

2007-06-19abs ↗pdf ↗

Proves orbifold singularities for Ricci-flat metrics on certain Kähler varieties.

problem Regularity of singular Ricci-flat Kähler metrics on Kähler varieties with log terminal singularities.
method Analyzes orbifold singularities of metrics restricted to the orbifold locus.
result Singular Ricci-flat Kähler metrics on Kähler varieties with log terminal singularities have orbifold singularities.

The global log canonical threshold (or Tian's alpha-invariant) plays an important role in the geometry of Fano varieties. Tian showed that Fano manifolds with big alpha-invariant can be equipped with a Kahler-Einstein metric. In recent years Donaldson drafted a programme to determine when a smooth Fano variety X admits…

2013-09-04abs ↗pdf ↗

Classifies normal stable Horikawa surfaces with smoothable singularities.

problem Characterizing surfaces with specific singularities and smoothability criteria.
method Classification and smoothability criterion based on log canonical singularities.
result Provides a criterion for global Q\mathbb{Q}-Gorenstein smoothability of Horikawa surfaces.

We relate the global log canonical threshold of a variety with torus action to the global log canonical threshold of its quotient. We apply this to certain Fano varieties and use Tian's criterion to prove the existence of Kahler-Einstein metrics on them. In particular, we obtain simple examples of Fano threefolds being…

2012-08-17abs ↗pdf ↗

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 XX be a canonically polarized variety, i.e. a complex projective variety such that its canonical class KXK_{X} defines an ample $\Q-$line bundle, and satisfying the conditions G1G_1 and S2S_2. Our main result says that XX admits a Kähler-Einstein metric iff XX has semi-log canonical singularities i.e. iff XX is…

2013-04-08abs ↗pdf ↗

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 ↗

This paper studies a specific blow-up algorithm for sop polynomials and their RLCT.

problem Determining the RLCT of sum-of-products polynomials through blow-up.
method Investigates a specific blow-up algorithm for sop polynomials to resolve their singularities.
result It is possible to resolve the singularities of sop polynomials using a specific blow-up algorithm.

Compact Kahler-Einstein manifolds converge to semi-log canonical models.

problem Compactness of Kahler-Einstein manifolds of negative scalar curvature.
method Gromov-Hausdorff convergence and Weil-Petersson metric extension.
result Convergence to a finite union of complete Kahler-Einstein metric spaces.

Let X be a complex projective variety and D a reduced divisor on X. Under a natural minimal condition on the singularities of the pair (X, D), which includes the case of smooth X with simple normal crossing D, we ask for geometric criteria guaranteeing various positivity conditions for the log-canonical divisor K_X+D. …

2012-07-31abs ↗pdf ↗

Classifies degenerations of complex projective plane with rational singularities.

problem Classifying singularities of complex projective plane.
method Assuming Wahl's conjecture, classifies degenerations using rational homology disk smoothing.
result Classifies surfaces with rational singularities, including new degenerations with non-log canonical singularities.

Paper answers Jin and Rubinstein's question about Fano manifolds.

problem Determining the equality of specific invariants for Fano manifolds.
method Used advanced computational methods including Chatgpt 5.5 pro and Danus system.
result Proved the equality of fixed-level equivariant alpha invariant and global log canonical threshold for Fano manifolds.

Canonical bundle formula due to Kawamata and others has played fundamental roles in algebraic geometry. We show that the canonical bundle formula has analytic characterization in terms of fiberwise integration, which confirms a folklore conjecture. The proof uses L2L^2 metrics and the valuative equivalence of plurisubh…

2019-10-15abs ↗pdf ↗

The paper studies Kähler-Einstein metrics with singularities and their limits.

problem Analyzing Kähler-Einstein metrics with crossing edge singularities and their limits.
method Extending Guenancia's techniques, the paper shows convergence of metrics under specific angle conditions.
result Negatively curved Kähler-Einstein crossing edge metrics converge to mixed cusp and edge metrics smoothly away from the divisor.

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.

Solves Tian's stabilization problem for toric Fano manifolds.

problem Tian's stabilization problem for equivariant global log canonical thresholds.
method Expressed complex singularity exponents in terms of support and gauge functions from convex geometry.
result First general result on Tian's problem.

We survey some recent topics on singularities, with a focus on their connection to the minimal model program. This includes the construction and properties of dual complexes, the proof of the ACC conjecture for log canonical thresholds and the recent progress on the `local stability theory' of an arbitrary Kawamata log…

2017-12-04abs ↗pdf ↗