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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.

168,742 papers · 148 categories

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48 results for unrestricted link function

New method optimizes policies without assuming known link functions between preferences and rewards.

problem Policy alignment with unknown and unrestricted link functions.
method Formulates an ff-divergence-constrained reward maximization problem, learning policies directly.
result Induces a semiparametric single-index binary choice model for policy alignment.

We study learning problems involving arbitrary classes of functions FF, distributions XX and targets YY. Because proper learning procedures, i.e., procedures that are only allowed to select functions in FF, tend to perform poorly unless the problem satisfies some additional structural property (e.g., that FF is co…

2017-07-17abs ↗pdf ↗

New tests for VaR and ES forecast encompassing using flexible link functions.

problem Testing forecast encompassing for Value at Risk and Expected Shortfall.
method Flexible link functions for testing convex forecast combinations and nonstandard asymptotic theory for boundary parameters.
result Tests based on new link functions outperform unrestricted linear link functions for one-step and multi-step forecasts.

Neural networks are vulnerable to adversarially-constructed perturbations of their inputs. Most research so far has considered perturbations of a fixed magnitude under some lpl_p norm. Although studying these attacks is valuable, there has been increasing interest in the construction of (and robustness to) unrestricted…

2019-05-07abs ↗pdf ↗

New algorithms ensure fair selection in combinatorial semi-bandit with unrestricted delays.

problem Fair selection in stochastic combinatorial semi-bandit with delayed feedback.
method Introduced merit-based fairness constraints and new bandit algorithms for reward and fairness.
result Achieved sublinear expected reward and fairness regrets with dependence on delay distribution quantiles.

Study compares adaptive vs fixed query learning methods.

problem Comparing adaptive and fixed query learning methods for task approximation.
method Examined in-context and agentic learning in two settings: unrestricted and realizable.
result Adaptivity does not hinder performance in unrestricted setting but can in realizable setting.

Adversarial examples are typically constructed by perturbing an existing data point within a small matrix norm, and current defense methods are focused on guarding against this type of attack. In this paper, we propose unrestricted adversarial examples, a new threat model where the attackers are not restricted to small…

2018-05-21abs ↗pdf ↗

Study of unrestricted virtual braid groups and their properties.

problem Characterize and describe homomorphisms of unrestricted virtual braid groups.
method Analyzing homomorphisms to symmetric groups and finite groups, characterizing images, proving characteristic subgroups, determining automorphism groups, and studying residual properties.
result Complete description of homomorphisms from UVBnUVB_n to SnS_n for n5n\geq 5.

We propose a novel approach for generating unrestricted adversarial examples by manipulating fine-grained aspects of image generation. Unlike existing unrestricted attacks that typically hand-craft geometric transformations, we learn stylistic and stochastic modifications leveraging state-of-the-art generative models. …

2019-11-20abs ↗pdf ↗

Generative models create indistinguishable adversarial objects for object detection.

problem Creating unrestricted adversarial examples for object detection.
method Search over latent space of GAN for adversarial objects.
result Generated adversarial objects are indistinguishable from non-adversarial objects and transferable.

New methods reduce extrapolation errors in feature importance.

problem Flawed feature importance methods using unrestricted permutations lead to extrapolation errors.
method Three new approaches: conditional model reliance, Knockoffs with Gaussian transformation, and restricted ALE plot designs.
result Theoretical and numerical results show our strategies reduce/eliminate extrapolation.

The study extends classical results on harmonic functions to Riemannian manifolds with non-tangential boundary limits.

problem Extending classical results on harmonic functions to Riemannian manifolds with non-tangential boundary limits.
method Investigated the restricted mean-value property on Riemannian manifolds, focusing on non-tangential boundary behavior.
result Extended a classical result of Fenton to non-positively curved Harmonic manifolds of purely exponential volume growth.

Recently, it is proven that generalized Robertson-Walker space-times in all orthogonal subspaces of Gray's decomposition but one(unrestricted) are perfect fluid space-times. GRW space-times in the unrestricted subspace are identified by having constant scalar curvature. Generalized quasi-Einstein GRW space-times have a…

2019-04-27abs ↗pdf ↗

We consider an insurance entity endowed with an initial capital and a surplus process modelled as a Brownian motion with drift. It is assumed that the company seeks to maximise the cumulated value of expected discounted dividends, which are declared or paid in a foreign currency. The currency fluctuation is modelled as…

2016-03-24abs ↗pdf ↗

Motivated by the resurgence of neural networks in being able to solve complex learning tasks we undertake a study of high depth networks using ReLU gates which implement the function xmax{0,x}x \mapsto \max\{0,x\}. We try to understand the role of depth in such neural networks by showing size lowerbounds against such network …

2017-11-08abs ↗pdf ↗

This paper tackles the computational complexity of finding approximate stationary points in non-convex optimization.

problem Finding approximate stationary points in non-convex optimization problems.
method PLS-completeness, zero-order algorithms, and gradient queries.
result The query complexity of finding approximate stationary points is Θ(1/ε) for d=2.

A stochastic model helps maintain insufficiently funded pension funds.

problem Maintaining pension funds that are underfunded and require external financing.
method A time-homogeneous diffusion process with a barrier is used to model the unrestricted reserves value, and a renewal-reward process models the financing effort.
result Expected values and cost evaluations of maintenance are derived, and the approach is applied to a generalized Brownian motion process.

Study improves cryptocurrency price prediction using deep learning with trading and social media indicators.

problem Predicting price movements of cryptocurrencies using deep learning.
method Used deep learning algorithms (MLP, CNN, LSTM, ALSTM) on hourly and daily data of Bitcoin and Ethereum.
result Unrestricted model with trading and social media indicators outperforms restricted model.

We provide a new approach to training neural models to exhibit transparency in a well-defined, functional manner. Our approach naturally operates over structured data and tailors the predictor, functionally, towards a chosen family of (local) witnesses. The estimation problem is setup as a co-operative game between an …

2019-02-26abs ↗pdf ↗

ScoreAG generates unrestricted adversarial images maintaining semantic integrity.

problem Limited robustness evaluations due to p\ell_p-norm constraints.
method Score-Based Adversarial Generation (ScoreAG) using score-based generative models.
result ScoreAG improves robustness assessments across multiple benchmarks.

Least Squares Estimators are suboptimal for 5D convex functions.

problem Suboptimality of Least Squares Estimators in estimating multidimensional convex functions.
method Analysis of natural subclasses of convex functions in random and fixed design settings.
result Risk of LSE is n2/dn^{-2/d} while minimax risk is n4/(d+4)n^{-4/(d+4)} for d5d \geq 5.

Polynomial-time DP algorithm for learning Gaussians with matching sample complexity.

problem Learning Gaussian distributions while maintaining privacy.
method General framework for reducing DP estimation to non-private, polynomial-time algorithm for Gaussian learning.
result Matching sample complexity to information-theoretic upper bound for Gaussian learning.

This paper proposes BAT to balance accuracy and robustness in adversarial training.

problem Balancing accuracy and robustness in adversarial training models.
method Blind adversarial training (BAT) uses a cutoff-scale strategy to adaptively estimate a nonuniform budget for AEs.
result BAT improves the overall robustness of adversarial training models.

PGNs dynamically infer and use graph structures to improve model generalization.

problem Static graph structures inferred by machine learning practitioners are often suboptimal for tasks.
method PGNs augment graphs with dynamically inferred pointers for improved model generalization.
result PGNs outperform unrestricted GNNs and Deep Sets on dynamic graph connectivity tasks.

Paper introduces methods for more reliable probabilistic predictions with confidence intervals.

problem Inaccurate labeling of datasets due to unreliable probabilistic predictions from weak labeling functions.
method Proposes a methodology to provide confidence intervals for label probabilities using uncertainty sets of distributions.
result Improves reliability of probabilistic predictions and provides confidence intervals for label probabilities.

Algorithm tackles large-scale portfolio optimization with higher moments, improving computational efficiency.

problem Optimizing portfolios with higher moments (variance, skewness, kurtosis) for large asset universes is computationally infeasible.
method Developed a structure-exploiting algorithm based on Yau's affine-normal descent, working directly with return matrix.
result Algorithm avoids explicit higher-order tensors and exploits quartic structure for efficient computation.

Study on the Euler-Plateau energy with elastic modulus, focusing on minimizers and critical surfaces.

problem Minimizing the Euler-Plateau energy with elastic modulus.
method Analyzing the energy functional and its minimizers, considering different boundary conditions and topological constraints.
result Potential minimizers are highly dependent on physical rigidity parameters, and the area of critical surfaces can be computed from boundary data.

For links with vanishing pairwise linking numbers, the link components bound pairwise disjoint surfaces in B4B^{4}. In this paper, we describe the set of genera of such surfaces in terms of the hh-function, which is a link invariant from Heegaard Floer homology. In particular, we use the hh-function to give lower bou…

2018-05-05abs ↗pdf ↗

Deep NLP models benefit from underlying structures in the data---e.g., parse trees---typically extracted using off-the-shelf parsers. Recent attempts to jointly learn the latent structure encounter a tradeoff: either make factorization assumptions that limit expressiveness, or sacrifice end-to-end differentiability. Us…

2018-09-03abs ↗pdf ↗

100 years ago exactly, in 1906, Hartogs published a celebrated extension phenomenon (birth of Several Complex Variables), whose global counterpart was stated in full generality later by Osgood (1929): holomorphic functions in a connected neighborhood V(bD) of a connected boundary bD contained in C^n (n >= 2) do extend …

2006-10-31abs ↗pdf ↗

The paper explores fibered and quasi-positive links, introducing new families and invariants.

problem Understanding the structure of LL-space links and their properties.
method Using the H-function as a concordance link invariant.
result Introduced a subfamily of fibered strongly quasi-positive LL-space links and an infinite family of non-quasi-positive LL-space links.

We give a necessary condition for a meromorphic function in several variables to give rise to a Milnor fibration of the local link (respectively of the link at infinity). In the case of two variables we give some necessary and sufficient conditions for the local link (respectively the link at infinity) to be fibred.

2005-07-15abs ↗pdf ↗