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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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229458686915 · Jun 202019922001200920172026
48 results for down-closed convex sets

New method tackles online DR-submodular maximization with improved regret guarantees.

problem Online maximization of non-monotone DR-submodular functions over down-closed convex sets.
method 1/e-linearization through exponential reparametrization, surrogate potential, and reduction to online linear optimization.
result Achieves O(T1/2)O(T^{1/2}) static regret with single gradient query per round, improving state of the art.

In this paper, we study fundamental problems of maximizing DR-submodular continuous functions that have real-world applications in the domain of machine learning, economics, operations research and communication systems. It captures a subclass of non-convex optimization that provides both theoretical and practical guar…

2019-09-25abs ↗pdf ↗

DR-submodular continuous functions are important objectives with wide real-world applications spanning MAP inference in determinantal point processes (DPPs), and mean-field inference for probabilistic submodular models, amongst others. DR-submodularity captures a subclass of non-convex functions that enables both exact…

2017-11-04abs ↗pdf ↗

The paper explores different smooth map notions on convex sets and their relationships.

problem Exploring and comparing different smooth map notions on convex sets.
method Constructing a function that doesn't extend to a smooth function on any open neighborhood but does for CkC^k functions.
result Diffeological and Sikorski smoothness notions do not coincide for all convex sets.

This note generalizes the visual angle to convex sets in 3D space.

problem Analyzing geometric properties of convex sets in 3D space.
method Generalizing the visual angle to convex sets in Euclidean space and expressing geometric quantities in terms of integrals of functions related to the solid angle.
result Invariant quantities of the original convex set can be expressed by integrals of functions related to the solid angle.

In an earlier paper we showed that the radial expansion of a hyperbolic convex set in the Poincaré disk about any point inside it results in a hyperbolic convex set. In this work, we generalize this result by showing that the asymmetric expansion of a hyperbolic convex set about any point inside it also results in a hy…

2020-02-11abs ↗pdf ↗

The paper explores connections between perimeter, area, and visual angle of convex sets.

problem Understanding geometric properties of convex sets through visual angle and related measurements.
method Establishing universal formulas and characterizing convex sets of constant width.
result Crofton's formula is the unique universal formula relating visual angle, length, and area.

Study finds a non-locally contractible rr-convex set.

problem Find an rr-convex set which is not locally contractible.
method Constructs a counterexample of a non-locally contractible rr-convex set.
result Proves that the class of supports with positive reach of absolutely continuous distributions includes strictly the class of rr-convex supports.

In this article a class of closed convex sets in the Euclidean nn-space which are the convex hull of their profiles is described. Thus a generalization of Krein-Milman theorem\cite{Lay:1982} to a class of closed non-compact convex sets is obtained. Sufficient and necessary conditions for convexity, affinity and starsh…

2013-01-04abs ↗pdf ↗

We define a class of L-convex-concave subsets of RPn\Bbb{R}P^n, where L is a projective subspace of dimension l in RPn\Bbb{R}P^n. These are sets whose sections by any (l+1)-dimensional space L' containing L are convex and concavely depend on L'. We introduce an L-duality for these sets, and prove that the L-dual to an L-…

2002-03-19abs ↗pdf ↗

Study contractibility of boundaries in convex sets and limit sets of subgroups.

problem Understanding contractibility of boundaries and wildness of limit sets in geometric structures.
method Use sufficient conditions for contractibility, study coarse upper curvature bounds, and analyze interpolation in geodesic metric spaces.
result Conditions for contractibility of boundaries and properties of limit sets are established.

A mean-convex set can be regarded as a barrier for the construction of minimal surfaces. Namely, if we are given a mean-convex set and a null-homotopic Jordan curve on its boundary, then there exists an embedded minimal disk with boundary the given curve contained in the starting mean-convex set. Does a mean-convex set…

2011-12-19abs ↗pdf ↗

Solves equality case in isoperimetric inequality for non-convex domains.

problem Equality case in relative isoperimetric inequality outside convex sets.
method Analyzes non-convex domains to settle the equality case.
result Solves the equality case for relative isoperimetric inequality outside arbitrary convex sets.

An open convex set in real projective space is called divisible if there exists a discrete group of projective automorphisms which acts co-compactly. There are many examples of such sets and a theorem of Benoist implies that many of these examples are strictly convex, have C1C^1 boundary, and have word hyperbolic divid…

2013-08-19abs ↗pdf ↗

New algorithms for differentially private optimization in convex and non-convex settings with near-optimal rates.

problem Differentially private optimization in convex and non-convex settings.
method Developed algorithms for convex and non-convex settings with near-optimal excess population risk.
result Achieved near-optimal rates in near-linear time for convex settings and nearly dimension independent rates for non-convex settings.

The paper studies stability and singularities of a two-convex level set flow.

problem Stability and singularities of a two-convex level set flow.
method Assumes two-convex initial hypersurface and finitely many singular times, then shows the singular set has finitely many connected components.
result Near each connected component of the singular set, the perturbed flow has the same type of singular set.

Paper solves Minkowski problem for non-compact convex sets with asymptotic boundary conditions.

problem Solving Minkowski problem for non-compact convex sets with asymptotic boundary conditions.
method Combining covolume, Hadamard variational formula, and geometric interpretation.
result Solved Minkowski problem for non-compact convex sets under asymptotic conditions.

A spherical set is called convex if for every pair of its points there is at least one minimal geodesic segment that joins these points and lies in the set. We prove that for n >= 3 a complete locally-convex (topological) immersion of a connected (n-1)-manifold into the n-sphere is a surjection onto the boundary of a c…

2007-08-23abs ↗pdf ↗

The usual notion of set-convexity, valid in the classical Euclidean context, metamorphoses into several distinct convexity types in the more general Riemannian setting. By studying this phenomenon in reverse, we characterize complete manifolds for which certain convexity types are assumed a priori to coincide.

2016-11-26abs ↗pdf ↗

Characterizes convex cocompact actions in projective space with dynamical properties.

problem Understanding convex cocompact group actions in projective space.
method Dynamical characterization and expansion property analysis.
result Equivalence of convex cocompactness to an expansion property in different Grassmannians.

Optimal hidden-target learning for online inventory optimization on general convex sets.

problem Online inventory optimization (OIO) on arbitrary bounded convex capacity sets.
method Maintaining a hidden target and projecting it onto the feasible order-up-to set.
result The method improves the best known regret guarantee for OIO on general convex sets from inverse to inverse-square-root dependence on the common-demand probability.

The paper proves a rigidity theorem for non-compact convex sets in hyperbolic 3-space.

problem Determining a closed convex set in hyperbolic 3-space by its boundary metric.
method Pogorelov's rigidity theorem, Hausdorff measure, and complex analysis techniques.
result The intrinsic path metric on the boundary determines a closed convex set up to isometry under certain conditions.

Paper extends capillary convex body results to anisotropic setting with Alexandrov-Fenchel inequalities.

problem Extending capillary convex body results to anisotropic setting.
method Developed theory for anisotropic capillary convex bodies in half-space and established Alexandrov-Fenchel inequality for mixed volumes.
result Established a general Alexandrov-Fenchel inequality for mixed volumes of anisotropic capillary convex bodies, weakening and extending previous results.

The paper studies invariant convex sets in representations with nontrivial copolarity.

problem Understanding the face structure of invariant convex sets in representations with nontrivial copolarity.
method Proves that the face structure of an invariant convex set is determined by its intersection with a fat section, and that a face is exposed if and only if the corresponding face of the intersection is exposed.
result The face structure of invariant convex sets is completely determined by their intersections with fat sections, and exposed faces are preserved.

Efficient algorithms for online convex optimization with limited switching decisions.

problem Online convex optimization with limited switching decisions.
method Presented computationally efficient algorithms for both general and strongly convex losses.
result Regret bounds of O(T/S)O(T/S) for general convex losses and O~(T/S2)\widetilde O(T/S^2) for strongly convex losses.

Two groups with specific limit sets in hyperbolic spaces are identified.

problem Identifying convex cocompact subgroups with specific limit sets in real hyperbolic spaces.
method Examples of subgroups generated by reflections and rotations with limit sets as Pontryagin spheres and Menger curves.
result Examples of convex cocompact subgroups with limit sets as Pontryagin spheres and Menger curves are found.

In this paper we have generalized the notion of λλ-radial contraction in complete Riemannian manifold and developed the concept of pλp^λ-convex function. We have also given a counter example proving the fact that in general λλ-radial contraction of a geodesic is not necessarily a geodesic. We have also deduced some r…

2017-10-15abs ↗pdf ↗

We prove some results concerning the boundary of a convex set in $\H^n$. This includes the convergence of curvature measures under Hausdorff convergence of the sets, the study of normal points, and, for convex surfaces, a generalized Gauss equation and some natural characterizations of the regular part of the Gaussian …

2017-10-05abs ↗pdf ↗

Many classical algorithms are found until several years later to outlive the confines in which they were conceived, and continue to be relevant in unforeseen settings. In this paper, we show that SVRG is one such method: being originally designed for strongly convex objectives, it is also very robust in non-strongly co…

2015-06-05abs ↗pdf ↗

The paper studies convexity of products of squared Euclidean distances.

problem Convexity of products of squared Euclidean distances.
method Proved a convexity principle and applied it to products of squared distances, computed Hessian-positive regions and exact convexity levels.
result Computed exact convexity and quasiconvexity truncation levels for the two-centre model.

New algorithm exploits curvature of feasible sets for fast online convex optimization.

problem Online convex optimization with fast rates.
method Adapting FTL algorithm to curvature of feasible sets.
result Achieves logarithmic regret bound of O(ρlogT)O(ρ\log T) in stochastic environments.

Non-compact convex sets in hyperbolic 3-space are rigid under isometries.

problem Rigidity of non-compact convex sets in hyperbolic 3-space
method Proving rigidity using Pogorelov's theorem and properties of locally convex surfaces
result Any intrinsic isometry between the boundaries of two non-compact closed convex subsets extends to a global isometry of the ambient space