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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.

168,932 papers · 148 categories

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12243648 · May 202619922001200920172026
48 results for divisorial contractions

Establishes K"ahler-Ricci flow on log canonical varieties.

problem Existence and convergence of K"ahler-Ricci flow on varieties with log canonical singularities.
method Generalizes previous results for klt singularities, proves convergence, and constructs solutions with flips.
result Existence and convergence of K"ahler-Ricci flow on semi-log canonical models.

We prove the existence and uniqueness of the weak Kahler-Ricci flow on projective varieties with log terminal singularities. It is also shown that the weak Kahler-Ricci flow can be uniquely continued through divisorial contractions and flips if they exist. We then propose an analytic version of the Minimal Model Progra…

2009-09-26abs ↗pdf ↗

Equivalence proven between divisorial stability and quotient log divisorial stability.

problem Equivalence of divisorial stability and log divisorial stability under finite group actions.
method Interpolation technique and equivariant divisorial stability construction.
result Equivariant divisorial stability of a polarized variety is equivalent to log divisorial stability of its quotient.

The paper solves a 5-manifold foliation problem using a Sasaki-Ricci flow.

problem Solving foliation singularities on Sasakian 5-manifolds.
method Applying the Sasaki-Ricci flow to resolve cyclic quotient foliation singularities.
result Proves a Sasaki analogue of the analytic minimal model program.

We introduce a new effective stability named "divisorial stability" for Fano manifolds which is weaker than K-stability and is stronger than slope stability along divisors. We show that we can test divisorial stability via the volume function. As a corollary, we prove that the first coordinate of the barycenter of the …

2015-08-17abs ↗pdf ↗

The paper shows how to destabilize unstable Fano varieties using stability thresholds.

problem Optimally destabilizing K-unstable Fano varieties.
method Using divisorial valuations and special test configurations to induce stability thresholds.
result Fano varieties degenerate to uniquely determined twisted K-polystable varieties.

We prove that among all Kollár components obtained by plt blow ups of a klt singularity o(X,D)o \in (X, D), there is at most one that is (log-)K-semistable. We achieve this by showing that if such a Kollár component exists, it uniquely minimizes the normalized volume function introduced in [Li15a] among all divisorial valu…

2016-04-19abs ↗pdf ↗

We discuss a technique to construct Ricci-flat hermitian metrics on complements of (some) anticanonical divisors of almost homogeneous manifolds and discuss when this metric is complete and Kähler. This construction has a strong interplay with invariance groups of the same dimension as the manifold acting with an open …

2003-07-11abs ↗pdf ↗

Paper rigorously defines Feynman graph integrals on Kähler manifolds.

problem Establishing convergence of Feynman graph integrals on Kähler manifolds.
method Using Getzler's rescaling technique, graph integrands are extended to forms with divisorial-type singularities in the compactification of configuration spaces.
result Feynman graph integrals are rigorously defined as Cauchy principal value integrals.

We compute a closed formula for the class of the closure of the locus of curves in Mg\overline{\mathcal{M}}_g that admit an abelian differential of signature κ=(k1,...,kg2)κ=(k_1,...,k_{g-2}).

2015-09-11abs ↗pdf ↗

We investigate the notion of symplectic divisorial compactification for symplectic 4-manifolds with either convex or concave type boundary. This is motivated by the notion of compactifying divisors for open algebraic surfaces. We give a sufficient and necessary criterion, which is simple and also works in higher dimens…

2014-07-02abs ↗pdf ↗

Proves existence of Kähler-Einstein metrics in big cohomology classes.

problem Existence of Kähler-Einstein metrics in big cohomology classes.
method Using a divisorial stability condition and Fujita-Odaka type delta invariants, building up from scratch the theory of pluripotential theory.
result Uniform Yau-Tian-Donaldson existence theorem for Kähler-Einstein metrics in the big cohomology class setting.

The paper explores positivity and irreducibility in Hurwitz spaces related to differentials of the second kind.

problem Positivity and irreducibility in Hurwitz spaces of certain covers of the projective line.
method Analyzes strata of differentials of the second kind with fixed multiplicities of zeros and poles, and applies this to show positivity and irreducibility in Hurwitz spaces.
result The Hurwitz spaces of degree dd, genus gg covers of P1\mathbb{P}^1 with pure branching at all but possibly one branch point are irreducible under certain conditions.

For any Q\mathbb{Q}-Gorenstein klt singularity (X,o)(X,o), we introduce a normalized volume function vol^\widehat{\rm vol} that is defined on the space of real valuations centered at oo and consider the problem of minimizing vol^\widehat{\rm vol}. We prove that the normalized volume has a uniform positive lower bound by pro…

2015-11-25abs ↗pdf ↗

Study of K-moduli of prime Fano threefolds of genus twelve, proving boundary purely divisorial.

problem Understanding the boundary of K-moduli of prime Fano threefolds of genus twelve.
method Developed a modular relation between Fano threefolds and their anticanonical K3 surfaces, proving forgetful morphism is an open immersion.
result Proved the boundary of K-moduli of V22V_{22} is purely divisorial and consists of four irreducible components.

Let VV be a regular neighborhood of a negative chain of 22-spheres (i.e. exceptional divisor of a cyclic quotient singularity), and let Bp,qB_{p,q} be a rational homology ball which is smoothly embedded in VV. Assume that the embedding is simple, i.e. the corresponding rational blow-up can be obtained by just a sequen…

2019-04-09abs ↗pdf ↗

Study shows hypercomplex twistor spaces lack divisors and special metrics.

problem Characterizing properties of hypercomplex twistor spaces.
method Analyzing the general fiber's lack of divisors and curves, proving trascendental degree and absence of special metrics.
result Proves hypercomplex twistor spaces have no divisors, curves, Kähler, or pluriclosed metrics.

Study collapsing Calabi-Yau metrics and flows on fiber spaces.

problem Understanding the behavior of Calabi-Yau metrics and flows during collapsing.
method Analyzing the collapsing of Calabi-Yau metrics and Kähler-Ricci flows on fiber spaces.
result Identify the collapsed Gromov-Hausdorff limit and bounds for Hausdorff measure.

The paper defines two types of hyperbolicity for complex manifolds and proves related results.

problem Defining and studying hyperbolicity for a broader class of complex manifolds.
method Introducing SKT hyperbolicity and Gauduchon hyperbolicity, proving results using SKT and Gauduchon metrics.
result Every SKT hyperbolic manifold is also Kobayashi/Brody hyperbolic and every Gauduchon hyperbolic manifold is divisorially hyperbolic.

The paper explores coalescent contractions in contractible spaces, providing criteria and examples.

problem Existence and absence of coalescent contractions in contractible spaces.
method Analysis of contractible finite simplicial complexes and criteria for coalescent contractions.
result Criteria for contractible finite simplicial complexes that ensure no coalescent contractions.

This is a continuation to the paper [arXiv:1511.08164] in which a problem of minimizing normalized volumes over Q\mathbb{Q}-Gorenstein klt singularities was proposed. Here we consider its relation with K-semistability, which is an important concept in the study of Kähler-Einstein metrics on Fano varieties. In particul…

2015-12-22abs ↗pdf ↗

In an online contract selection problem there is a seller which offers a set of contracts to sequentially arriving buyers whose types are drawn from an unknown distribution. If there exists a profitable contract for the buyer in the offered set, i.e., a contract with payoff higher than the payoff of not accepting any c…

2013-05-15abs ↗pdf ↗

Optimal execution strategy for merger & acquisition contracts with price impact.

problem Optimal execution and pricing of financial derivatives in M&A deals.
method Indifference utility arguments, considering linear and nonlinear contracts.
result Linear contracts are more expensive and vulnerable to manipulation.

This paper develops a method to select a reference contract for multi-contract quoting to minimize execution risk.

problem Minimizing execution risk in multi-contract quoting sequences.
method Develops a diagnostic framework using order-flow Hawkes forecasts and CLF to select a stable reference contract.
result Event-history and LOB-state signals offer complementary views for reference-contract selection.

Improved security of smart contracts by classifying them into four categories.

problem Detecting and classifying vulnerabilities in smart contracts efficiently.
method Used AWD-LSTM for multi-class classification, addressing class imbalance.
result Achieved a weighted average Fbeta score of 90.0%.

Study on contracting maps and their rigidity under curvature constraints.

problem Rigidity of contracting maps between manifolds with positive curvature.
method Analysis of curvature pinching and contracting conditions involving singular values.
result Established the relation between curvature pinching and contracting conditions.

We study locally compact contractive local groups, that is, locally compact local groups with a contractive pseudo-automorphism. We prove that if such an object is locally connected, then it is locally isomorphic to a Lie group. We also prove a related structure theorem for locally compact contractive local groups whic…

2009-09-24abs ↗pdf ↗

This paper presents some partial answers to the following question. QUESTION. If a normal space X is the union of an increasing sequence of open sets U(1), U(2), U(3) ... such that each U(n) contracts to a point in X, must X be contractible? The main results of the paper are: THEOREM 1. If a normal space X is the union…

2016-06-16abs ↗pdf ↗

Study on reinsurance decisions using mean-variance criterion with irreversible contracts.

problem Optimizing reinsurance premiums and contracts in a Stackelberg game with irreversible contracts.
method Unified singular control framework applied to both discrete and continuous time reinsurance contracts.
result A single once-for-all reinsurance contract is preferred over multiple contracts, and the signing time is crucial.

Optimal contracts help principals delegate data collection in decentralized ML.

problem Dealing with information asymmetries in decentralized ML.
method Design of optimal and near-optimal contracts addressing uncertainty in model quality and performance.
result Simple linear contracts achieve 1-1/e fraction of optimal utility.

Optimal contracts are found for agents with quadratic effort costs.

problem Finding optimal contracts in principal-agent problems with quadratic effort costs.
method Modeling the problem using Hamilton-Jacobi-Bellman (HJB) equations and proving the existence of classical solutions.
result Existence of optimal contracts for agents with quadratic effort costs is proven.

Fair insurance contracts are designed to handle default risk using cooperative game theory.

problem Designing fair insurance contracts in the presence of default risk.
method Cooperative game theory to specify premiums and participation in benefit.
result Fair benefit participation emerges as a game outcome involving residual risks.

Paper proposes machine learning for managing complex buyback contracts.

problem Managing complex buyback contracts, especially accelerated share repurchase.
method Proposes a machine learning method to optimally manage buyback contracts.
result Recovery of strategies similar to those obtained with partial differential equations and tree methods, but without the curse of dimensionality.