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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.

168,657 papers · 148 categories

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148296444592 · Jun 202019922001200920172026
48 results for subquadratic time

Improved efficient robust regression with near-linear time and subquadratic samples.

problem Robust linear regression with unknown covariance matrix under Gaussian covariates.
method Near-linear time algorithm using subquadratic samples, complemented by SQ and polynomial lower bounds.
result Achieves prediction error O(εκ)O(\sqrt{εκ}) for εκ1εκ\lesssim 1, improving over prior works.

New method trains shallow neural networks with subquadratic width scaling.

problem Training shallow neural networks with optimal width scaling.
method Polyak-Lojasiewicz condition, smoothness, standard data assumptions, random matrix theory.
result Subquadratic scaling on network width with standard initialization strategies.

We prove an interior Schauder estimate for the Laplacian on metric products of two dimensional cones with a Euclidean factor, generalizing the work of Donaldson and reproving the Schauder estimate of Guo-Song. We characterize the space of homogeneous subquadratic harmonic functions on products of cones, and identify sc…

2020-02-18abs ↗pdf ↗

This work addresses dynamic KDE data structures with robustness to adversarial queries.

problem Efficient KDE data structures for dynamic changing data distributions.
method Developed a theoretical framework for KDE data structures that support subquadratic space, sublinear updates, and adaptive queries.
result Theoretical framework and practical implementation of KDE data structures robust to adversarial queries.

When performing regression on a dataset with pp variables, it is often of interest to go beyond using main linear effects and include interactions as products between individual variables. For small-scale problems, these interactions can be computed explicitly but this leads to a computational complexity of at least $…

2016-10-17abs ↗pdf ↗

New algorithms speed up attention computation for large models by limiting matrix entries.

problem Efficiently compute attention matrices for large language models.
method Developed algorithms that exploit the structure of the attention matrix AA to achieve subquadratic time complexity.
result There is a sharp transition at B=Θ(logn)B = Θ(\sqrt{\log n}) for efficient computation of attention matrices.

We study the non Ricci flat gradient steady Kähler Ricci soliton with non-negative Ricci curvature and weak integrability condition of the scalar curvature SS, namely limrr1BrS=0\underline{\lim}_{r\to \infty} r^{-1}\int_{B_r} S=0, and show that it is a quotient of Σ×Cn1k×NkΣ\times \mathbb{C}^{n-1-k}\times N^k, where ΣΣ and NN denot…

2019-08-27abs ↗pdf ↗

In this paper we propose a Bayesian nonparametric approach to modelling sparse time-varying networks. A positive parameter is associated to each node of a network, which models the sociability of that node. Sociabilities are assumed to evolve over time, and are modelled via a dynamic point process model. The model is a…

2016-07-06abs ↗pdf ↗

New algorithm solves unbalanced optimal transport on trees in quasi-linear time.

problem Efficiently solving unbalanced optimal transport problems on trees.
method Proposed an algorithm that solves a more general unbalanced optimal transport problem exactly in quasi-linear time on a tree metric.
result Solves unbalanced optimal transport on trees in quasi-linear time (less than one second for a tree with one million nodes).

We study the number and the length of systoles on complete finite area orientable hyperbolic surfaces. In particular, we prove upper bounds on the number of systoles that a surface can have (the so-called kissing number for hyperbolic surfaces). Our main result is a bound which only depends on the topology of the surfa…

2014-08-26abs ↗pdf ↗

New findings show GD converges to a linear interpolator even with quadratic loss function under certain conditions.

problem Understanding convergence of Gradient Descent with quadratic loss functions.
method Parameterized linear regression with quadratic loss function, empirical and theoretical analysis.
result Gradient Descent converges to a linear interpolator even with quadratic loss function under the Edge of Stability regime.

Research shows quadratic growth in derivative maxima for certain interval diffeos with parabolic fixed points.

problem Analyzing the growth of derivative maxima for C2C^2 interval diffeomorphisms with parabolic fixed points.
method Examining C2C^2 diffeomorphisms with only parabolic fixed points, focusing on tangency and repelling behavior.
result Maximal growth of derivative maxima is exactly quadratic for diffeomorphisms with a non-quadratic tangency to identity at a repelling fixed point.

The study proves manifolds with positive scalar curvature can be decomposed into spherical and toroidal pieces.

problem Proving manifolds with positive scalar curvature can be decomposed into simpler pieces.
method Using a topological approach, the researchers prove a decomposition theorem for manifolds with positive scalar curvature and subquadratic decay.
result The manifold MM carries a complete Riemannian metric of uniformly positive scalar curvature, answering a conjecture of Gromov.

LoLCATs improves linearized LLM quality with less memory and compute.

problem Linearizing large language models (LLMs) often degrades model quality and requires expensive training.
method Two-step method: attention transfer and low-rank adaptation.
result Significant improvement in linearizing quality with 20+ points on 5-shot MMLU.

Entity resolution seeks to merge databases as to remove duplicate entries where unique identifiers are typically unknown. We review modern blocking approaches for entity resolution, focusing on those based upon locality sensitive hashing (LSH). First, we introduce kk-means locality sensitive hashing (KLSH), which is b…

2018-10-11abs ↗pdf ↗

The paper extends a Liouville theorem to biharmonic functions on manifolds with nonnegative Ricci curvature.

problem Proving that biharmonic functions with certain growth conditions are constant or harmonic.
method Using a new local L2L^2 estimate for the Laplacian of biharmonic functions combined with a mean value inequality.
result Any biharmonic function of subquadratic growth on a manifold with nonnegative Ricci curvature must be harmonic, and any of sublinear growth must be constant.

A general class of Lorentzian metrics, M0xR2M_0 x R^2, ds2=<.,.>+2dudv+H(x,u)du2ds^2 = <.,.> + 2 du dv + H(x,u) du^2, with (M0,<.,.>(M_0, <.,.> any Riemannian manifold, is introduced in order to generalize classical exact plane fronted waves. Here, we start a systematic study of their main geodesic properties: geodesic completeness, geodesic connected…

2002-11-05abs ↗pdf ↗

Alternating Minimization is a widely used and empirically successful heuristic for matrix completion and related low-rank optimization problems. Theoretical guarantees for Alternating Minimization have been hard to come by and are still poorly understood. This is in part because the heuristic is iterative and non-conve…

2013-12-03abs ↗pdf ↗

The paper explores efficient graph algorithms on geometric graphs and their computational limits.

problem Efficiently solving spectral graph theory problems on geometric graphs.
method Investigates algorithms and hardness results for multiplying vectors, finding spectral sparsifiers, and solving Laplacian systems on K\mathsf{K}-graphs.
result Formal limitations on subquadratic time algorithms for spectral graph theory problems on geometric graphs, including the Gaussian kernel and Neural tangent kernels.

LaPSRL achieves optimal regret for isoperimetric RL distributions.

problem Designing RL algorithms with sublinear regret for non-log-concave distributions.
method Posterior Sampling (PSRL) and Langevin sampling (LaPSRL) for isoperimetric distributions.
result LaPSRL achieves order-optimal regret and subquadratic complexity.

The paper examines functional properties on manifolds with very negative curvature.

problem Functional properties on manifolds with very negative curvature.
method New Hardy-type inequalities and first and second order inequalities.
result Functional properties typically hold in manifolds with polynomially growing negative curvature.

We improve prediction risk estimation for large datasets using sketching and ridge regression.

problem Estimating prediction risks for large datasets efficiently and accurately.
method Random matrix theory, generalized cross validation, sketched ridge regression ensembles, and ensemble trick.
result Consistent risk estimation and prediction intervals for large-scale datasets.

We consider the problem of performing linear regression over a stream of dd-dimensional examples, and show that any algorithm that uses a subquadratic amount of memory exhibits a slower rate of convergence than can be achieved without memory constraints. Specifically, consider a sequence of labeled examples $(a_1,b_1)…

2019-04-18abs ↗pdf ↗

This paper examines how adversarial perturbations affect model performance and equilibrium learning.

problem Adversarial perturbations and covariate shifts impact model performance and equilibrium learning.
method Characterizes the extrapolation region in regression and classification, analyzes dynamics of adversarial learning games.
result Establishes two directional convergence results: a blessing in regression and a curse in classification.

Analyzes intrinsic time in financial markets, linking it to physical time.

problem Understanding the intrinsic nature of time in financial data.
method Presented an analytic relationship linking intrinsic and physical time, using empirical scaling laws.
result A novel empirical scaling law relating intrinsic time variability to overshoots.

Proposes a method to allocate time budgets in mixed criticality systems.

problem Managing execution time variability in mixed criticality systems.
method Quantifies execution time variability using statistical dispersion parameters and proposes a heuristic to allocate time budgets.
result The proposed heuristic reduces the probability of exceeding allocated budgets.

Modeling regime shifts in co-evolving time series with interactions and time-dependency.

problem Discovering and modeling regime shifts in multiple time series with relationships and time-dependent behaviors.
method Modeling interactions and time-dependency in co-evolving time series using a mapping grid and dynamic network representation for regime identification and time-dependent Cox regression for regime transition probabilities.
result A principled approach for modeling interactions and time-dependency in co-evolving time series.

Logarithmic regret for continuous-time reinforcement learning.

problem Continuous-time Markov decision processes with unknown transition probabilities and holding times.
method Upper confidence reinforcement learning, mean holding time estimation, stochastic comparison of point processes.
result Logarithmic regret bound achieved in finite time.

We provide the proof that the space of time series data is a Kolmogorov space with T0T_{0}-separation axiom using the loop space of time series data. In our approach we define a cyclic coordinate of intrinsic time scale of time series data after empirical mode decomposition. A spinor field of time series data comes fro…

2016-06-10abs ↗pdf ↗

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 apply the theory of continuous time random walks to study some aspects of the extreme value problem applied to financial time series. We focus our attention on extreme times, specifically the mean exit time and the mean first-passage time. We set the general equations for these extremes and evaluate the mean exit ti…

2004-06-23abs ↗pdf ↗

We investigate the waiting-time distribution of the absolute return in the Korean stock-market index KOSPI. We define the waiting time as a time interval during which the normalized absolute return remains continuously below a threshold rcr_c. Through an exponential bin plot, we observe that the waiting-time distributi…

2005-08-30abs ↗pdf ↗

EDICT learns evidential distributions for irregular time series, improving predictions and uncertainty quantification.

problem Challenges in predicting and characterizing uncertainty for irregular time series data.
method EDICT (Evidential Distributions for Irregular Time Series) learns a continuous-time evidential distribution.
result EDICT achieves competitive performance on time series classification tasks and provides better uncertainty quantification.