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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.

169,341 papers · 148 categories

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2965928881,184 · Jun 202019922001200920182026
48 results for complex 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 ↗

The paper examines conditions for the Kobayashi metric to be Gromov hyperbolic on complex convex sets.

problem Conditions for the Kobayashi metric to be Gromov hyperbolic on complex convex sets.
method Develops necessary and sufficient conditions for Gromov hyperbolicity, extends results to C1C^1-smooth boundaries, and provides counterexamples.
result Gromov hyperbolicity of Kobayashi metric on C\mathbb{C}-convex sets with C1C^1-smooth boundary, and counterexamples showing boundary regularity is necessary.

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.

Lower bounds for geodesically convex optimization show curvature negatively impacts complexity.

problem Understanding the impact of curvature on the query complexity of geodesically convex optimization.
method Building on recent lower bounds, the study proposes and proves new lower bounds for various settings of geodesically convex optimization.
result Negative curvature is detrimental to the complexity of geodesically convex optimization.

Paper improves privacy in ERM with faster algorithms and broader applicability.

problem Privacy-preserving machine learning with empirical risk minimization.
method Develops faster algorithms for differentially private ERM in various settings.
result Achieves optimal or near-optimal utility bounds with less gradient complexity.

Develops theory of relatively geometric actions on CAT(0) cube complexes.

problem Understand actions of relatively hyperbolic groups on CAT(0) cube complexes.
method Introduces and studies relatively geometric actions, proving key results.
result Proves full relatively quasi-convex subgroups are convex compact.

New research shows parallel optimization is ineffective for convex problems.

problem The inefficiency of parallel optimization methods for convex problems.
method Lower bounds analysis in the local oracle model of computation.
result Parallel and randomized algorithms cannot speed up convex optimization in various geometries and objective functions.

Improved variance reduction for Riemannian non-convex optimization with adaptive batch size.

problem Optimizing non-convex functions on Riemannian manifolds.
method Batch size adaptation in R-SVRG, R-SRG, and R-SPIDER.
result Achieves lower total complexities for various non-convex functions.

New method solves complex optimization problems faster.

problem Minimizing a convex smooth objective over the optimal solution set of another convex smooth problem.
method Uses a cutting plane approach to approximate the lower-level problem and an accelerated gradient method to update the upper-level objective.
result Shows that the method requires at most O(max{1/εf,1/εg})\mathcal{O}(\max\{1/\sqrt{ε_{f}}, 1/ε_g\}) iterations to achieve εfε_f-suboptimality and εgε_g-infeasibility.

New algorithms ensure reproducibility and optimal convergence in convex optimization.

problem Trade-off between reproducibility and convergence rate in convex optimization.
method Regularization-based algorithms for smooth convex minimization and minimax optimization.
result Achieves optimal reproducibility and near-optimal gradient complexity for various oracle settings.

New methods solve complex optimization problems without strong convexity assumptions.

problem Complex bilevel optimization problems with minimax lower-level structures.
method Penalty-based first-order methods for bilevel minimax optimization.
result Achieves εε-KKT point with improved oracle complexity.

For a strongly pseudo-convex complex Finsler manifold M, a bundle U of adapted unitary frames is canonically defined. A non-linear Hermitian connection on U, invariant under local biholomorphic isometries, is given and it proved to be unique. By means of such connection, an absolute parallelism on U is determined and a…

1999-10-07abs ↗pdf ↗

New findings show Rademacher complexities are not crucial for learning complexities.

problem Understanding the sample complexity of learning with squared loss in convex classes.
method Novel learning procedure combining mean estimation and Talagrand's generic chaining method.
result Sample complexity is determined by the limiting Gaussian process, not Rademacher complexities.

Optimizes average of convex functions with tight bounds.

problem Minimizing the average of m convex functions with gradient and prox oracles.
method Tight upper and lower bounds on complexity for deterministic and randomized optimization.
result Optimal methods for smooth and non-smooth functions, showing significant gap between deterministic and randomized settings.

A generalized optimistic method for saddle point problems with improved complexity.

problem Solving convex-concave saddle point problems efficiently.
method Proposes a generalized optimistic method that includes the optimistic gradient method as a special case, handling constrained saddle point problems with composite objective functions and arbitrary norms.
result Best-known global iteration complexity bounds for first-, second-, and higher-order methods.

Paper solves a complex equation for unbounded convex sets.

problem Solving the LpL_p dual Minkowski problem for unbounded closed sets.
method Using variational properties of Monge-Ampère functionals, the paper proves existence, regularity, and uniqueness of solutions.
result Existence, regularity, and uniqueness of solutions to the Monge-Ampère type equation for p1p \geq 1.

Constructs hyperbolic reflection groups with 3D limit sets.

problem Existence of convex cocompact groups with specific limit sets.
method Inputting a simplicial complex into a construction process yields a hyperbolic reflection group.
result Answers Kapovich's question affirmatively by creating a thin subgroup of an arithmetic lattice.

In this note we prove convexity, in the sense of Colding-Naber, of the regular set of solutions to some complex Monge-Ampere equations with conical singularities along simple normal crossing divisors. In particular, any two points in the regular set can be joined by a smooth minimal geodesic lying entirely in the regul…

2014-03-25abs ↗pdf ↗

New methods optimize complex optimization problems with improved efficiency.

problem Optimizing complex problems with a convex lower-level objective.
method Uses stochastic cutting planes and conditional gradient updates.
result Improves complexity for both convex and non-convex upper-level functions.

Paper studies how to combine regret minimizers for solving complex games.

problem Solving large-scale extensive-form games with constraints.
method Derives a calculus for constructing regret minimizers for composite convex sets.
result Local regret minimizers for simpler sets can be combined into an aggregate for composite sets.

The paper shows how to simplify complex optimization problems into simpler ones.

problem Complex multiobjective optimization problems.
method Proving strongly convex problems are simplicial under certain conditions and demonstrating transformations.
result Strongly convex problems can be simplified into simpler ones via generic linear perturbations.

Deep neural networks help recover two signals from noisy mixtures.

problem Recovering two signals from noisy subgaussian mixtures with prior structural information.
method Used deep generative neural networks (GNNs) to solve the demixing problem for Lipschitz signals.
result Proved a sample complexity bound for nearly optimal recovery error, extending previous results.

New algorithm finds optimal sample complexity for pure exploration with multiple good answers.

problem Determining the optimal number of samples needed to explore multiple good answers in a bandit problem.
method Derive lower bound using game equilibrium, extend Track-and-Stop algorithm to multiple answers.
result New algorithm has asymptotic sample complexity matching the derived lower bound.

For convex domains, automorphism group and limit set properties are described.

problem Characterize the automorphism group and limit set of convex domains.
method Detailed analysis of automorphism group structure and limit set properties for convex domains with C1,εC^{1,ε} boundary.
result The automorphism group has finitely many components and the limit set is homeomorphic to a sphere.

The study of Kähler metrics on domains restricts their boundary geometry.

problem Understanding the geometry of domains with negatively pinched Kähler metrics.
method Analyzing the existence and properties of negatively pinched Kähler metrics on domains.
result The boundary of a convex domain without complex subvarieties of positive domain if it admits a complete Kähler metric with pinched negative holomorphic bisectional curvature.

Suppose ττ is a train track on a surface SS. Let C(τ)C(τ) be the set of isotopy classes of simple closed curves carried by ττ. Masur and Minsky [2004] prove C(τ)C(τ) is quasi-convex inside the curve complex C(S)C(S). We prove the complement, C(S)C(τ)C(S) - C(τ), is quasi-convex.

2014-10-17abs ↗pdf ↗

Paper revisits set membership estimation for linear systems with relaxed disturbance bounds.

problem Set membership estimation for linear systems with disturbances bounded by convex sets.
method Adopted block-martingale small-ball condition and random perturbed control policies to establish convergence rates.
result Established convergence rates for disturbances bounded by general convex sets.

Improved Frank-Wolfe algorithm for constrained convex optimization with nearest extreme point oracle.

problem Constrained smooth convex minimization with limited linear optimization oracle access.
method Frank-Wolfe algorithm with nearest extreme point oracle.
result Improved complexity bounds for specific feasible sets, including linear convergence for 0ext10 ext{--}1 polytopes.

Paper solves minimax optimization gap with near-optimal algorithms.

problem Designing efficient algorithms for smooth and strongly-convex-strongly-concave minimax problems.
method Accelerated proximal point method and accelerated solver for minimax proximal steps.
result First algorithm with gradient complexity matching the lower bound up to logarithmic factors.

Let S be the boundary of a handlebody M. We prove that the set of curves in S that are boundaries of disks in M, considered as a subset of the complex of curves of S, is quasi-convex.

2003-07-07abs ↗pdf ↗

In this paper, we investigate the topology of a class of non-Kähler compact complex manifolds generalizing that of Hopf and Calabi-Eckmann manifolds. These manifolds are diffeomorphic to special systems of real quadrics in Cn\Bbb C^n which are invariant with respect to the natural action of the real torus $(\Bbb S^1)^n…

2004-05-05abs ↗pdf ↗

Study quotients of curve complex actions by mapping class group.

problem Understanding actions of mapping class group on curve complex quotients.
method Cone off uniformly quasi-convex subspaces to form symmetric curve sets, non-maximal train track sets, and compression body disc sets. Analyze actions of mapping class group on these quotients.
result Actions of mapping class group on quotients are strongly WPD, non-elementary, and have infinite diameter.

A new method for distributed optimization reduces communication rounds without minibatches.

problem Efficient training in distributed machine learning with different data distributions.
method A primal-dual method (GA-MSGD) applied to the Lagrangian of distributed optimization.
result Achieves linear convergence in communication rounds for strongly convex objectives.