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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.

168,695 papers · 148 categories

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8162432 · May 202619922001200920172026
48 results for doubly non-negative

Proposes a new method to improve regression models with reweighted samples.

problem Improves regression models' performance under low sample sizes and covariate perturbations.
method Reparametrizes sample weights using a doubly non-negative matrix and solves the reweighted estimate efficiently.
result Adversarial reweighting strategy delivers promising results on various datasets.

Sharp upper bounds found for solutions of a specific equation on Riemannian manifolds.

problem Finding upper bounds for solutions of a specific equation on Riemannian manifolds.
method Proved sharp upper estimates of weak subsolutions to the Leibenson equation on Riemannian manifolds with non-negative Ricci curvature.
result Improved and proved a conjecture about upper bounds for solutions of the Leibenson equation.

The paper examines Einstein doubly warped product manifolds with a semi-symmetric metric connection.

problem Characterizing Einstein doubly warped product manifolds with a semi-symmetric metric connection.
method Deriving curvature formulas and proving necessary and sufficient conditions for a manifold to be a warped product.
result Obtained results for Einstein doubly warped product manifolds and Einstein-like doubly warped product manifolds.

Characterizes and examines gradient solitons on doubly warped product manifolds.

problem Understanding gradient solitons on specific manifold structures.
method Characterizations and examinations of various types of gradient solitons on doubly warped product manifolds.
result Effects of gradient solitons on factor manifolds and specific curvature properties of doubly warped products.

We show that if the connected sum of two knots with coprime Alexander polynomials is doubly slice, then the Ozsváth-Szabó correction terms as smooth double sliceness obstructions vanish for both knots. Recently, Jeffrey Meier gave smoothly slice knots that are topologically doubly slice, but not smoothly doubly slice. …

2016-11-23abs ↗pdf ↗

We define an obstruction for a knot to be Z[Z]-homology ribbon, and use this to provide restrictions on the integers that can occur as the triple linking numbers of derivative links of knots that are either homotopy ribbon or doubly slice. Our main application finds new non-doubly slice knots. In particular this gives …

2018-02-02abs ↗pdf ↗

In this paper we study fundamental geometric properties of doubly warped product immersion which is an extension of warped product immersion. Moreover, we study geometric inequality for doubly warped products isometrically immersed in arbitrary Riemannian manifolds.

2013-10-05abs ↗pdf ↗

We construct an infinite family of smoothly slice knots that we prove are topologically doubly slice. Using the correction terms coming from Heegaard Floer homology, we show that none of these knots is smoothly doubly slice. We use these knots to show that the subgroup of the double concordance group consisting of smoo…

2014-01-06abs ↗pdf ↗

The twisting number of a ribbon knot is at least as large as its doubly slice genus.

problem Proving a lower bound for the twisting number of ribbon knots in terms of their doubly slice genus.
method Analyzing symmetric unions and tangle replacements to establish the bound.
result Ribbon knots have arbitrarily high twisting numbers, matching their doubly slice genus.

In this paper, we introduce horizontal and vertical warped product Finsler manifold. We prove that every C-reducible or proper Berwaldian doubly warped product Finsler manifold is Riemannian. Then, we find the relation between Riemmanian curvatures of doubly warped product Finsler manifold and its components, and consi…

2011-10-31abs ↗pdf ↗

New methods combine machine learning with doubly robust estimators for better treatment effect estimation.

problem Estimating average treatment effects from observational data.
method Doubly robust methods using machine learning techniques.
result Machine learning improves the performance of doubly robust estimators.

New method glues Scherk surfaces into minimal surfaces, limiting possible outcomes.

problem Limiting the outcomes of gluing Scherk surfaces into minimal surfaces.
method Constructing minimal surfaces by stacking and gluing doubly periodic Scherk surfaces.
result Except for special cases, gluing more Scherk surfaces results in known minimal surfaces.

We prove that an odd pretzel knot is doubly slice if it has 2n+12n+1 twist parameters consisting of n+1n+1 copies of aa and nn copies of a-a for some odd integer aa. Combined with the work of Issa and McCoy, it follows that these are the only doubly slice odd pretzel knots.

2019-04-29abs ↗pdf ↗

Characterizes certain Kähler manifolds with doubly-warped product structures.

problem Understanding Kähler manifolds with specific geometric properties.
method Obata-type characterization for Kähler manifolds with doubly-warped product structures.
result Complete description of Kähler doubly-warped product structures with Einstein metrics.

Using Traizet's regeneration method, we prove that for each positive integer n there is a family of embedded, doubly periodic minimal surfaces with parallel ends in Euclidean space of genus 2n-1 and 4 ends in the quotient by the maximal group of translations. The genus 2n-1 family converges smoothly to 2n copies of Sch…

2016-04-21abs ↗pdf ↗

A knot in the 3-sphere is called doubly slice if it is a slice of an unknotted 2-sphere in the 4-sphere. We give a bi-sequence of new obstructions for a knot being doubly slice. We construct it following the idea of Cochran-Orr-Teichner's filtration of the classical knot concordance group. This yields a bi-filtration o…

2004-11-06abs ↗pdf ↗

We consider the question of existence of embedded doubly periodic minimal surfaces in Euclidean 3-space with Scherk-type ends, surfaces that topologically are Scherk's doubly periodic surface with handles added in various ways. We extend the existence results of H. Karcher and F. Wei to more cases, and we find other ca…

2009-12-25abs ↗pdf ↗

A knot in the three-sphere is doubly slice if it is the cross-section of an unknotted two-sphere in the four-sphere. For low-crossing knots, the most complete work to date gives a classification of doubly slice knots through 9 crossings. We extend that work through 12 crossings, resolving all but four cases among the 2…

2015-04-13abs ↗pdf ↗

Corrects mismatch in consistency of nuisance estimators for doubly robust methods.

problem Mismatch in consistency of nuisance estimators in doubly robust methods.
method Calibrated debiased machine learning (calibrated DML) with isotonic regression adjustment.
result Calibrated DML yields doubly robust asymptotic normality with slower convergence of nuisance estimators.

We prove the existence of a family of embedded doubly periodic minimal surfaces of (quotient) genus gg with orthogonal ends that generalizes the classical doubly periodic surface of Scherk and the genus-one Scherk surface of Karcher. The proof of the family of immersed surfaces is by induction on genus, while the proo…

2010-07-30abs ↗pdf ↗

Pairs of elements in quaternionic hyperbolic space have zero measure of being strongly doubly reversible.

problem Characterizing pairs of elements in quaternionic hyperbolic space that are strongly doubly reversible.
method Analyzing conjugacy conditions and using Haar measure.
result The set of strongly doubly reversible pairs has Haar measure zero in $\PSp(n,1) imes \PSp(n,1)$.

We develop a theory of chain complex double-cobordism for chain complexes equipped with Poincaré duality. The resulting double-cobordism groups are a refinement of Ranicki's torsion algebraic LL-groups for localisations of a commutative ring with involution. The refinement is analogous to the difference between metabo…

2015-08-05abs ↗pdf ↗

Constructs a family of genus three minimal surfaces with parallel ends.

problem Creating embedded doubly periodic minimal surfaces with specific topological properties.
method Constructs a one-parameter family of surfaces with given Weierstrass data and solves the period problem.
result Solves the two dimensional period problem for the constructed surfaces.

Most known examples of doubly periodic minimal surfaces in R3\mathbb{R}^3 with parallel ends limit as a foliation of R3\mathbb{R}^3 by horizontal noded planes, with the location of the nodes satisfying a set of balance equations. Conversely, for each set of points providing a balanced configuration, there is a correspo…

2016-04-26abs ↗pdf ↗

Doubly-stochastic normalization improves robustness to heteroskedastic noise.

problem Robustness to heteroskedastic noise in affinity matrix construction.
method Doubly-stochastic normalization of the Gaussian kernel.
result Doubly-stochastic normalization converges to clean matrix with rate m1/2m^{-1/2} under heteroskedastic noise.

Obstructs Legendrian knots from being slices of concordances using doubly slice genus.

problem Obstructing Legendrian knots from being slices of concordances.
method Uses Eliashberg and Polterovitch's result on doubly slice genus as an obstruction.
result Obstructs Legendrian knots from being slices of concordances, including examples of Pretzel knots.