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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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481216 · May 202319922001200920172026
48 results for Calabi ansatz

The modified J-flow with Calabi ansatz shows convergence or blow-up behavior based on topological constants.

problem Analyzing the behavior of the modified J-flow with Calabi ansatz.
method Using the Calabi symmetry and studying the singularities of the flow.
result The modified J-flow with Calabi ansatz converges to a solution away from a variety, and blows up along the variety.

Invariant Kähler metrics on line bundles are derived from the Calabi ansatz.

problem Finding invariant scalar-flat Kähler metrics on line bundles over generalized flag varieties.
method Proved using the Calabi ansatz and uniqueness in each Kähler class.
result Existence of a unique scalar-flat Kähler metric in each Kähler class.

The abstract discusses special Lagrangians and their flow, proving conjectures and observing related phenomena.

problem Existence and long-time existence of special Lagrangian representatives and Lagrangian mean curvature flow.
method Gibbons-Hawking ansatz, circle-invariant hyperkaehler 4-manifolds, Calabi-Yau 2-folds, Thomas conjecture, Thomas-Yau conjecture.
result Proves versions of the Thomas conjecture and Thomas-Yau conjecture.

Study Kähler-Einstein edge metrics on Hirzebruch surfaces, verifying a conjecture and finding a rigid singularity.

problem Verifying a conjecture about Kähler-Einstein edge metrics on Hirzebruch surfaces.
method Using the Calabi ansatz, constructing a family of metrics and studying their angle deformation.
result Verification of a conjecture and finding a rigid singularity.

Method finds approximate Ricci-flat metrics on Calabi-Yau manifolds.

problem Finding analytic Kähler potentials for Calabi-Yau manifolds.
method Numerically calculating Ricci-flat Kähler potentials via machine learning and fitting to Donaldson's Ansatz.
result Simple analytic expressions for approximately Ricci-flat Kähler potentials are found, including explicit dependence on complex structure parameter.

We use a generalization of the Gibbons-Hawking ansatz to study the behavior of certain non-compact Calabi-Yau manifolds in the large complex structure limit. This analysis provides an intermediate step toward proving the metric collapse conjecture for toric hypersurfaces and complete intersections.

2003-04-08abs ↗pdf ↗

In the present paper we provide a description of complete Calabi-Yau metrics on the canonical bundle of generalized complex flag manifolds. By means of Lie theory we give an explicit description of complete Ricci-flat Kähler metrics obtained through the Calabi ansatz technique. We use this approach to provide several e…

2017-09-22abs ↗pdf ↗

We study and construct non-abelian hermitian Yang-Mills (HYM) instantons on Calabi-Yau cones. By means of a particular isometry preserving ansatz, the HYM equations are reduced to a novel Higgs-Yang-Mills flow on the Einstein-Kahler base. For any 2d-dimensional Calabi-Yau cone, we find explicit solutions of the flow eq…

2009-10-06abs ↗pdf ↗

Existence of Ricci flat metric on Kummer K3 surface proven.

problem Proving existence of Ricci flat metric on Kummer K3 surface.
method General strategy of Donaldson's gluing construction, compact elliptic theory on usual Hölder and Sobolev spaces, explicit isometry to Gibbons-Hawking ansatz.
result Existence of a Ricci flat metric on the Kummer K3 surface.

The paper constructs Einstein metrics on holomorphic bundles.

problem Finding complete conformally Kähler Einstein metrics on holomorphic bundles.
method Explicit momentum construction via ODE methods and Calabi ansatz.
result Non-trivial complete conformally Kähler Einstein metrics on certain holomorphic bundles are found.

This note gives a simple formula for the unique asymptotically conical Calabi-Yau metrics on the canonical bundle of a flag variety known to exist by the work of R. Goto and others. This is done by generalizing the well known Calabi Ansatz to general Kähler classes. We give some examples of explicit families, in partic…

2018-07-19abs ↗pdf ↗

An ansatz of Calabi allows construction of Kahler metrics in an Hermitian disk bundle over a Kahler manifold. We attempt to give a definitive treatment of this ansatz, with the following results: We give curvature conditions on the disk bundle that guarantee existence of families of complete Kahler metrics of constant …

1998-11-05abs ↗pdf ↗

In this note we use the Calabi ansatz, in the context of metrics with conical singularities along a divisor, to produce regular Calabi-Yau cones and Kähler-Einstein metrics of negative Ricci with a cuspidal point. As an application, we describe singularities and cuspidal ends of the completions of the complex hyperboli…

2018-04-18abs ↗pdf ↗

Joyce's criterion for sLag smoothings extended to non-compact, non-transverse intersections.

problem Existence of special Lagrangian smoothings for non-compact, non-transverse intersections.
method Leung-Yau-Zaslow transform, deformed Hermitian Yang-Mills connections, Calabi ansatz, mean curvature flow, Bridgeland stability conditions.
result Existence of sLag smoothings on stable loci with slope inequality.

Study of singularity formation in dHYM flow on a blown-up CP^3.

problem Analyzing singularity formation in the dHYM flow on a blown-up CP^3.
method Using Calabi ansatz, the paper studies the singularity formation of the dHYM cotangent flow on the one-point blow up of CP^3.
result An explicit example of singularity formation along the exceptional divisor, with a limit satisfying the corresponding singular dHYM equation.

We study the limiting behavior of the Kahler-Ricci flow on P(OPnOPn(1)(m+1))\mathbb{P}(\mathcal{O}_{\mathbb{P}^n} \oplus \mathcal{O}_{\mathbb{P}^n}(-1)^{\oplus (m+1)}), assuming the initial metric satisfies the Calabi symmetry. We show that the flow either shrinks to a point, collapses to Pn\mathbb{P}^n or contracts a subvariety of c…

2010-11-07abs ↗pdf ↗

We consider cones over manifolds admitting real Killing spinors and instanton equations on connections on vector bundles over these manifolds. Such cones are manifolds with special (reduced) holonomy. We generalize the scalar ansatz for a connection proposed by Harland and Nolle in such a way that instantons are parame…

2012-03-12abs ↗pdf ↗

In this note we prove that a special family of Killing potentials on certain Hirzebruch complex surfaces, found by Futaki and Ono, gives rise to new conformally Kähler, Einstein-Maxwell metrics. The correspondent Kähler metrics are ambitoric but they are not given by the Calabi ansatz. This answers in positive question…

2020-01-30abs ↗pdf ↗

We extend Calabi ansatz over Kähler-Einstein manifolds to Sasaki-Einstein manifolds. As an application we prove the existence of a complete scalar-flat Kähler metric on Kähler cone manifolds over Sasaki-Einstein manifolds. In particular there exists a complete scalar-flat Kähler metric on the toric Kähler cone manifold…

2007-03-05abs ↗pdf ↗

In the present work we provide a constructive method to describe contact structures on compact homogeneous contact manifolds. The main feature of our approach is to describe the Cartan-Ehresmann connection (gauge field) for principal circle bundles over complex flag manifolds by using elements of representation theory …

2018-01-09abs ↗pdf ↗

We construct gradient Kähler-Ricci solitons on Ricci-flat Kähler cone manifolds and on line bundles over toric Fano manifolds. Certain shrinking and expanding solitons are pasted together to form eternal solutions of the Ricci flow. The method we employ is the Calabi ansatz over Sasaki-Einstein manifolds, and the resul…

2009-10-20abs ↗pdf ↗

We review some previous results about the Calabi-Yau equation on the Kodaira-Thurston manifold equipped with an invariant almost-Kaehler structure and assuming the volume form invariant by the action of a torus. In particular, we observe that under some restrictions the problem is reduced to a Monge-Ampère equation by …

2016-09-04abs ↗pdf ↗

Solves a conjecture about hyperKähler manifolds using quaternionic Monge-Ampère equation.

problem Proving the solvability of a conjecture about hyperKähler manifolds with torsion.
method Solving quaternionic Monge-Ampère equation on hyperKähler manifolds without assuming flatness.
result Proves the conjecture for hyperKähler manifolds with trivial canonical bundle.

Constructs complete metrics and solitons on complex vector bundles.

problem Finding complete metrics and solitons on complex vector bundles.
method Employing the theory of hamiltonian 2-forms and constructing metrics on total spaces of vector bundles.
result Obtains new examples of asymptotically conical Kähler shrinkers, Calabi-Yau metrics, and steady solitons.

Let XX be a complex projective variety with only canonical singularities and with trivial canonical bundle. Let LL be an ample line bundle on XX. Assume that the pair (X,L)(X,L) is the flat limit of a family of smooth polarized Calabi-Yau manifolds. Assume that for each singular point xXx \in X there exist a Kahler-Ein…

2016-07-11abs ↗pdf ↗

Introduces new equations linking Kähler-Einstein and Hermitian-Yang-Mills theories.

problem Existence of solutions to coupled Kähler-Einstein and Hermitian-Yang-Mills equations.
method Moment map interpretation, Futaki invariant, Matsushima-Lichnerowicz theorem, deformation results.
result Nontrivial solutions produced under certain conditions.

Study solutions and singularities of G2-structures flows on specific manifolds.

problem Investigate singularities and solutions of G2-structures flows.
method Explicit solutions and singularities of Ricci-harmonic flow, Ricci-like flows, and negative gradient flow of G2-structures on specific manifolds.
result First examples of Type I singularities of Ricci-harmonic flow and Type IIb and Type III singularities of Ricci-like flows.

We use the twistorial construction of D-instantons in Calabi-Yau compactifications of type II string theory to compute an explicit expression for the metric on the hypermultiplet moduli space affected by these non-perturbative corrections. In this way we obtain an exact quaternion-Kahler metric which is a non-trivial d…

2014-12-28abs ↗pdf ↗

Study geometric operators on Tian-Yau spaces, finding L2L^2 harmonic forms and asymptotic regularity.

problem Analyzing geometric elliptic operators on Tian-Yau spaces.
method Use a-pseudodifferential calculus to determine L2L^2 harmonic forms and asymptotic regularity.
result Determine the space of L2L^2 harmonic forms and refined asymptotic regularity of ALH* structures.

New ansatz for generalized Kähler surfaces derived from hyperKähler ansatz.

problem Deriving a new ansatz for generalized Kähler surfaces.
method Generalized Gibbons-Hawking ansatz for nondegenerate Poisson structure with biholomorphic S1S^1 action.
result Classification of all complete solutions with smallest symmetry group.

Expressive quantum circuits are harder to train due to flatter cost landscapes.

problem Designing quantum circuits that are both expressive and trainable.
method Deriving a relationship between expressibility and gradient magnitude, extending barren plateau phenomenon.
result Highly expressive ansätze exhibit flatter cost landscapes, making them harder to train.

If a Spin(7)Spin(7) manifold N8N^8 admits a free S1S^1 action preserving the fundamental 44-form then the quotient space M7M^7 is naturally endowed with a G2G_2-structure. We derive equations relating the intrinsic torsion of the Spin(7)Spin(7)-structure to that of the G2G_2-structure together with the additional data of a Higg…

2019-09-09abs ↗pdf ↗

We classify superpotentials for cohomogeneity one Ricci solitons, finding new ones and proving non-existence in higher dimensions.

problem Classifying superpotentials for cohomogeneity one Ricci solitons.
method Hamiltonian system analysis and specific ansatz constructions.
result New superpotential found and non-existence proven in higher dimensions.

A new approach to quantum machine learning circuits reduces training difficulties.

problem Challenges in training deep quantum circuits due to flat training landscapes.
method Variable structure approach (VAns) to build ansatzes, applying rules for gate growth and removal.
result VAns successfully mitigates trainability and noise-related issues, improving performance in various applications.

We consider an extension of the results of S. Bando, R. Kobyashi, G. Tian, and S. T. Yau on the existence of Ricci-flat Kähler metrics on quasi-projective varieties Y=X\D with α[D]=c_1(X), α>1. The requirement that D admit a Kähler-Einstein metric is generalized to the condition that the link S in the normal bundle of …

2008-03-02abs ↗pdf ↗

A homogeneous Gibbons-Hawking ansatz is described, leading to 4-dimensional hyperkahler metrics with homotheties. In combination with Blaschke products on the unit disc in the complex plane, this ansatz allows one to construct infinite-dimensional families of such hyperkahler metrics that are, in a suitable sense, comp…

2008-07-01abs ↗pdf ↗