High Minima of Gaussian Processes: Overshoots and Minimizer Locations
- URL: http://arxiv.org/abs/2607.20714v1
- Date: Wed, 22 Jul 2026 20:31:36 GMT
- Title: High Minima of Gaussian Processes: Overshoots and Minimizer Locations
- Abstract summary: We show that, conditionally on $M>u$, the scaled overshoot $u(M-u)$ converges, as $utoinfty$, to an exponential random variable with mean $_*2$.<n>The results are illustrated by stationary Gaussian processes, fractional Brownian motion, and fractional Brownian sheet.
- Score: 0.0
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: Let $X(t)$, $t\in K$, be a centred Gaussian process with continuous sample paths on a compact metric space $K$, and let $M=\min_{t\in K}X(t)$. Let $σ_*^2$ denote the minimum covariance energy associated with $X$, and assume that $σ_*^2>0$. Motivated by the results of \cite{chakrabarty2018asymptotic} for smooth Gaussian processes, we show that, conditionally on $M>u$, the scaled overshoot $u(M-u)$ converges, as $u\to\infty$, to an exponential random variable with mean $σ_*^2$. Moreover, every weak subsequential limit of the conditional law of a measurable minimizer of $X$ is an optimal covariance-energy measure. In particular, if this measure is unique, then the conditional law converges weakly to it. The results are illustrated by stationary Gaussian processes, fractional Brownian motion, and fractional Brownian sheet.
Related papers
- Zero-SNR Analyticity of the Scalar MMSE Is Equivalent to Gaussianity [0.7499255435598924]
We prove that the minimum mean-square error $operatornamemmse_X(s)$ is analytic at zero signal-to-noise ratio if and only if $X$ is Gaussian.<n>A zero of $mgeq 2$ splits according to the roots of a Hermitemath and instead contributes a prefactor $n-m/2er_msqrt2n$.
arXiv Detail & Related papers (2026-09-14T05:07:20Z) - Scaling Limits of Constant-Stepsize SGD at Flat Minima [5.608222858044445]
We study Markovian noise generated by a contractive driving chain.<n>For gradient descent (SGD) with a constant stepsize $$, the invariant law of the iterates, centered at a minimizer, describes the behavior of the algorithm over long time horizons.<n>We show that this behavior changes fundamentally for convex objectives $H$ with flat minima and (sub)quadratic tails.
arXiv Detail & Related papers (2026-07-17T17:22:46Z) - Estimation of the sub-Gaussian parameter [7.4076878426925035]
The sub-Gaussian random variable $X$ is defined as $2_* = s_upin mathbbR L()$ where $L() = frac22 log mathbbE eX$ is a weighted cumulant generating function.<n>Despite the ubiquity of sub-Gaussian random variables, the estimation of $2_*$ has received little attention and is not yet well understood.
arXiv Detail & Related papers (2026-06-04T16:48:31Z) - Information-Computation Tradeoffs for Noiseless Linear Regression with Oblivious Contamination [65.37519531362157]
We show that any efficient Statistical Query algorithm for this task requires VSTAT complexity at least $tildeOmega(d1/2/alpha2)$.
arXiv Detail & Related papers (2025-10-12T15:42:44Z) - Proving the Limited Scalability of Centralized Distributed Optimization via a New Lower Bound Construction [57.93371273485736]
We consider a centralized distributed learning setup where all workers jointly find an unbiased bound LDeltaepsilon2,$ better poly-logarithmically in $n$, even in the homogeneous (i.i.d.) case, where all workers access the same distribution.
arXiv Detail & Related papers (2025-06-30T13:27:39Z) - Allocating Variance to Maximize Expectation [2.25491649634702]
We design efficient approximation algorithms for maximizing the expectation of the supremum of families of Gaussian random variables.<n>Such expectation problems occur in diverse applications, ranging from utility auctions to learning mixture models in quantitative genetics.
arXiv Detail & Related papers (2025-02-25T18:59:46Z) - A Unified Framework for Uniform Signal Recovery in Nonlinear Generative
Compressed Sensing [68.80803866919123]
Under nonlinear measurements, most prior results are non-uniform, i.e., they hold with high probability for a fixed $mathbfx*$ rather than for all $mathbfx*$ simultaneously.
Our framework accommodates GCS with 1-bit/uniformly quantized observations and single index models as canonical examples.
We also develop a concentration inequality that produces tighter bounds for product processes whose index sets have low metric entropy.
arXiv Detail & Related papers (2023-09-25T17:54:19Z) - $L^1$ Estimation: On the Optimality of Linear Estimators [64.76492306585168]
This work shows that the only prior distribution on $X$ that induces linearity in the conditional median is Gaussian.
In particular, it is demonstrated that if the conditional distribution $P_X|Y=y$ is symmetric for all $y$, then $X$ must follow a Gaussian distribution.
arXiv Detail & Related papers (2023-09-17T01:45:13Z) - A note on $L^1$-Convergence of the Empiric Minimizer for unbounded
functions with fast growth [0.0]
For $V : mathbbRd to mathbbR$ coercive, we study the convergence rate for the $L1$-distance of the empiric minimizer.
We show that in general, for unbounded functions with fast growth, the convergence rate is bounded above by $a_n n-1/q$, where $q$ is the dimension of the latent random variable.
arXiv Detail & Related papers (2023-03-08T08:46:13Z) - Sparse Signal Detection in Heteroscedastic Gaussian Sequence Models:
Sharp Minimax Rates [1.0309387309011746]
We study the signal detection problem against sparse alternatives, for known sparsity $s$.
We find minimax upper and lower bounds over the minimax separation radius $epsilon*$ and prove that they are always matching.
Our results reveal new phase transitions regarding the behavior of $epsilon*$ with respect to the level of sparsity, to the $Lt$ metric, and to the heteroscedasticity profile of $Sigma$.
arXiv Detail & Related papers (2022-11-15T23:53:39Z) - The Sample Complexity of Robust Covariance Testing [56.98280399449707]
We are given i.i.d. samples from a distribution of the form $Z = (1-epsilon) X + epsilon B$, where $X$ is a zero-mean and unknown covariance Gaussian $mathcalN(0, Sigma)$.
In the absence of contamination, prior work gave a simple tester for this hypothesis testing task that uses $O(d)$ samples.
We prove a sample complexity lower bound of $Omega(d2)$ for $epsilon$ an arbitrarily small constant and $gamma
arXiv Detail & Related papers (2020-12-31T18:24:41Z) - Sample Complexity of Asynchronous Q-Learning: Sharper Analysis and
Variance Reduction [63.41789556777387]
Asynchronous Q-learning aims to learn the optimal action-value function (or Q-function) of a Markov decision process (MDP)
We show that the number of samples needed to yield an entrywise $varepsilon$-accurate estimate of the Q-function is at most on the order of $frac1mu_min (1-gamma)5varepsilon2+ fract_mixmu_min (1-gamma)$ up to some logarithmic factor.
arXiv Detail & Related papers (2020-06-04T17:51:00Z) - Curse of Dimensionality on Randomized Smoothing for Certifiable
Robustness [151.67113334248464]
We show that extending the smoothing technique to defend against other attack models can be challenging.
We present experimental results on CIFAR to validate our theory.
arXiv Detail & Related papers (2020-02-08T22:02:14Z)
This list is automatically generated from the titles and abstracts of the papers in this site.
This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.