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arXiv research

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.

168,694 papers · 148 categories

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119239358477 · Jun 202019922001200920172026
48 results for shrinking estimators

The study examines four-dimensional gradient Ricci solitons and their properties.

problem Characterizing four-dimensional complete gradient shrinking Ricci solitons.
method Proving properties and providing curvature estimates for solitons under specific conditions.
result Conditions for four-dimensional complete gradient shrinking Ricci solitons.

Sharp Li-Yau equality proven for shrinking Ricci solitons without curvature assumptions.

problem Classifying shrinking Ricci solitons without curvature or volume restrictions.
method Proving the sharp Li-Yau equality for conjugate heat kernel on shrinking Ricci solitons.
result Several estimates and classification of four-dimensional, non-compact shrinking Ricci solitons.

Study on 4D Ricci solitons with specific curvature properties.

problem Characterizing 4D complete gradient shrinking Ricci solitons with half positive isotropic curvature.
method Curvature estimates, strong maximum principle, classification arguments.
result New classification results for gradient shrinking Kähler-Ricci solitons and 4D complete gradient shrinking Ricci solitons with half nonnegative isotropic curvature.

It is shown that the diameter of a compact shrinking Ricci soliton has a universal lower bound. This is proved by extending universal estimates for the first non-zero eigenvalue of Laplacian on compact Riemannian manifolds with lower Ricci curvature bound to a twisted Laplacian on compact shrinking Ricci solitons.

2010-07-11abs ↗pdf ↗

New classification for higher-dimensional shrinking Ricci solitons with positive isotropic curvature.

problem Classifying shrinking gradient Ricci solitons with positive isotropic curvature in higher dimensions.
method Combining pinching estimates and WPIC1 curvature conditions.
result A complete ancient solution to the Ricci flow in dimensions n9n\geq9 with uniformly PIC must be weakly PIC2.

In this paper we derive a precise estimate on the growth of potential functions of complete noncompact shrinking solitons. Based on this, we prove that a complete noncompact gradient shrinking Ricci soliton has at most Euclidean volume growth. The latter result can be viewed as an analog of the well-known theorem of Bi…

2009-03-23abs ↗pdf ↗

The gradient shrinking ρρ-Einstein soliton is a triple (Mn,g,f)(M^n,g,f) such that Rij+fij=(ρR+λ)gij,R_{ij}+f_{ij}=(ρR+λ) g_{ij}, where (Mn,g)(M^n,g) is a Riemannian manifold, λ>0,ρR{0}λ>0, ρ\in\mathbb{R}\setminus\{0\} and ff is the potential function on MnM^n. In this paper, using algebraic curvature estimates and the Yamabe-Sobolev inequality, w…

2016-12-27abs ↗pdf ↗

Paper proves a Liouville theorem for solitons with constant curvature.

problem Understanding harmonic functions on specific geometric structures.
method Proved a Liouville theorem without gradient estimates.
result Finite dimensionality of harmonic functions with polynomial growth.

The paper estimates eigenvalues for specific differential operators on curved spaces.

problem Estimating eigenvalues for a class of elliptic differential operators on Riemannian manifolds.
method Analyzes eigenvalue estimates for a broader class of elliptic differential operators in divergence form.
result Provides eigenvalue estimates for Gaussian shrinking solitons and specific domains.

We prove that a nn-dimensional, 4n64 \leq n \leq 6, compact gradient shrinking Ricci soliton satisfying a Ln/2L^{n/2}-pinching condition is isometric to a quotient of the round Sn\mathbb{S}^{n}. The proof relies mainly on sharp algebraic curvature estimates, the Yamabe-Sobolev inequality and an improved rigidity result f…

2015-09-24abs ↗pdf ↗

In the first part of the paper we derive integral curvature estimates for complete gradient shrinking Ricci solitons. Our results and the recent work of Lopez-Rio imply rigidity of gradient shrinking Ricci solitons with harmonic Weyl tensor. In the second part of the paper we address the issue of existence of harmonic …

2009-10-06abs ↗pdf ↗

PRESTO improves rare event prediction by shrinking towards proportional odds model.

problem Difficult to predict rare events due to class imbalance.
method PRESTO relaxes proportional odds model by estimating separate weights for transitions between categories, imposing L1 penalty to shrink towards proportional odds.
result PRESTO consistently estimates decision boundary weights under sparsity assumption, improving rare probability estimation.

The main purpose of this paper is to investigate the curvature behavior of four dimensional shrinking gradient Ricci solitons. For such soliton MM with bounded scalar curvature SS, it is shown that the curvature operator Rm\mathrm{Rm} of MM satisfies the estimate RmcS|\mathrm{Rm}|\le c\,S for some constant cc. Moreov…

2014-10-14abs ↗pdf ↗

The study pinches the rigidity of self-shrinking surfaces in mean curvature flow.

problem Rigidity of self-shrinking hypersurfaces in mean curvature flow.
method Spectral upper-pinching theorem and weighted Poincaré estimate.
result Self-shrinking hypersurfaces are restricted to specific forms under certain conditions.

In this paper, we classify n-dimensional (n>3) complete Bach-flat gradient shrinking Ricci solitons. More precisely, we prove that any 4-dimensional Bach-flat gradient shrinking Ricci soliton is either Einstein, or locally conformally flat hence a finite quotient of the Gaussian shrinking soliton R4R^4 or the round cyl…

2011-05-16abs ↗pdf ↗

The least absolute shrinkage and selection operator (lasso) and ridge regression produce usually different estimates although input, loss function and parameterization of the penalty are identical. In this paper we look for ridge and lasso models with identical solution set. It turns out, that the lasso model with shri…

2014-01-10abs ↗pdf ↗

In [Cheeger-Tian 2005], Cheeger-Tian proved an εε-regularity theorem for 44-dimensional Einstein manifolds without volume assumption. They conjectured that similar results should hold for critical metrics with constant scalar curvature, shrinking Ricci solitons, Ricci flows in 44-dimensional manifolds and higher dim…

2017-07-18abs ↗pdf ↗

R2D2-Net improves Bayesian neural networks by preventing over-shrinkage of important weights.

problem Bayesian neural networks struggle with choosing appropriate priors, leading to over-shrinkage or poor predictive performance.
method Proposes R2D2-Net with an R^2-induced Dirichlet Decomposition prior and variational Gibbs inference algorithm.
result R2D2-Net effectively shrinks irrelevant coefficients while preventing key features from over-shrinkage.

We give two new proofs of Perelman's theorem that shrinking breathers of Ricci flow on closed manifolds are gradient Ricci solitons, using the fact that the singularity models of type I solutions are shrinking gradient Ricci solitons and the fact that non-collapsed type I ancient solutions have rescaled limits being sh…

2017-05-23abs ↗pdf ↗

We prove the following: Let (M,g,X) be a noncompact four dimensional shrinking soliton with bounded nonnegative curvature operator, then (M,g) is isometric to R^4 or a finite quotient of S^2xR^2 or S^3xR. In the process we also show that a complete shrinking soliton (M,g,X) with bounded curvature is gradient and k-nonc…

2007-10-30abs ↗pdf ↗

Complete shrinking soliton found on a specific complex surface.

problem Classifying complete shrinking gradient Kähler-Ricci solitons in two complex dimensions.
method Proved existence of a unique soliton with bounded scalar curvature on a specific blowup.
result Complete classification of such solitons in two complex dimensions.

We develop some estimates under the Ricci flow and use these estimates to study the blowup rates of curvatures at singularities. As applications, we obtain some gap theorems: supXRic\displaystyle \sup_X |Ric| and supXRmsupXR\displaystyle \sqrt{\sup_X |Rm|} \cdot \sqrt{\sup_X |R|} must blowup at least at the rate of type-I. Our estim…

2011-07-26abs ↗pdf ↗