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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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0111 · Sep 200719922001200920172026
23 results for K-unstability

Study finds limits for conical Kähler-Einstein metrics on unstable surfaces.

problem Optimal upper bounds for conical Kähler-Einstein metrics on K-unstable del Pezzo surfaces.
method Established optimal upper bounds for cone angles of Kähler-Einstein metrics with conical singularities.
result Optimal upper bounds for conical Kähler-Einstein metrics on K-unstable del Pezzo surfaces.

Segre varieties' hyperplane sections are unstable under certain conditions.

problem Stability of hyperplane sections of Segre varieties under different conditions.
method Proving instability with respect to any polarization for non-smooth or meqnm eq n cases.
result Normal hyperplane sections of Segre varieties are K-unstable under specified conditions.

The study examines K-polystability on Fano 4-folds with specific Lefschetz defects.

problem Investigating K-polystability on Fano 4-folds with Lefschetz defect at least 2.
method Examining 19 families of Fano 4-folds with Lefschetz defect 3 and 175 families with Lefschetz defect 2, proving K-polystability and instability.
result Exactly 5 out of 19 families of Fano 4-folds with Lefschetz defect 3 are K-polystable, and 5 out of 175 Casagrande-Druel Fano 4-folds with Lefschetz defect 2 are K-polystable.

The paper classifies and computes limits of equivariant compactifications of groups.

problem Classifying and computing limits of equivariant compactifications of groups.
method Equivariant normal R-test configurations and semistable limits.
result Semistable limits of K-unstable Fano group compactifications are computed.

K-polystability of a polarised variety is an algebro-geometric notion conjecturally equivalent to the existence of a constant scalar curvature Kähler metric. When a variety is K-unstable, it is expected to admit a "most destabilising" degeneration. In this note we show that if such a degeneration exists, then the limit…

2019-05-27abs ↗pdf ↗

Reverse Hölder inequalities on Fano metrics with applications to geodesics and singularities.

problem Establishing reverse Hölder inequalities on Kähler metrics of Fano varieties.
method Using log-concavity and properties of Ricci potentials, the inequality is proven for Fano manifolds with log terminal singularities.
result The inequality holds for Fano varieties with log terminal singularities and the constant depends only on p and the dimension of X.

Tian's criterion for K-stability states that a Fano variety of dimension nn whose alpha invariant is greater than nn+1\frac{n}{n+1} is K-stable. We show that this criterion is sharp by constructing singular Fano varieties with alpha invariants nn+1\frac{n}{n+1} that are not K-polystable for sufficiently large nn. We also…

2019-03-12abs ↗pdf ↗

On a K-unstable toric variety we show the existence of an optimal destabilising convex function. We show that if this is piecewise linear then it gives rise to a decomposition into semistable pieces analogous to the Harder-Narasimhan filtration of an unstable vector bundle. We also show that if the Calabi flow exists f…

2007-09-17abs ↗pdf ↗

We examine various examples of horosymmetric manifolds which exhibit interesting properties with respect to canonical metrics. In particular, we determine when the blow-up of a quadric along a linear subquadric admits Kähler-Einstein metrics, providing infinitely many examples of manifolds with no Kähler-Ricci solitons…

2019-11-19abs ↗pdf ↗

We provide an explicit resolution of the Abreu equation on convex labeled quadrilaterals. This confirms a conjecture of Donaldson in this particular case and implies a complete classification of the explicit toric Kähler-Einstein and toric Sasaki-Einstein metrics constructed in [6,22,14]. As a byproduct, we obtain a we…

2009-09-24abs ↗pdf ↗

It is shown that any, possibly singular, Fano variety X admitting a Kahler-Einstein metric is K-polystable, thus confirming one direction of the Yau-Tian-Donaldson conjecture in the setting of Q-Fano varieties equipped with their anti-canonical polarization. The proof exploits convexity properties of the Ding functiona…

2012-05-28abs ↗pdf ↗

The paper explores maximal destabilizers for both K-stability and Chow-stability in unstable situations.

problem Exploring maximal destabilizers for K-stability and Chow-stability in unstable situations.
method Using non-Archimedean pluripotential theory and idealistic assumptions, the paper provides a route to show that maximal K-destabilizers are quantized by maximal Chow-destabilizers.
result Maximal K-destabilizers are quantized by maximal Chow-destabilizers.

Study optimal degenerations of Fano threefolds, proving K-polystability and Kähler-Ricci solitons.

problem Optimal degenerations of K-unstable Fano threefolds.
method Explicitly determined degenerations, finding weighted K-polystable (X0,ξ0)(\mathcal{X}_0, ξ_0), studying moduli spaces.
result One moduli space is isomorphic to the GIT-moduli space of biconic curves, the other is a single point.

New stability concept for Poisson structures leads to constant curvature metrics.

problem Finding constant scalar curvature metrics in generalized Kähler geometry.
method Introducing Poisson K-stability and using infinite-dimensional momentum map techniques.
result Existence of constant scalar curvature symplectic generalized Kähler structures on Kähler-Einstein Fano manifolds.

Introduces Poisson K-stability for Kähler manifolds and proves existence of constant scalar curvature structures.

problem Stability conditions for Poisson structures on Kähler manifolds.
method Infinite-dimensional momentum map techniques.
result Existence of constant scalar curvature symplectic generalized Kähler structures on Kähler-Einstein Fano manifolds.