{"title":"Minimax optimality of kernel ridge regression when kernel eigenvalues decay polynomially or exponentially","authors":"Kwan-Young Bak , Woojoo Lee","doi":"10.1016/j.spl.2025.110526","DOIUrl":"10.1016/j.spl.2025.110526","url":null,"abstract":"<div><div>We investigate the minimax optimality of the kernel ridge regression by quantifying the estimation complexity owing to the dimensionality under the polynomial or exponential decay rates of the kernel function’s eigenvalues. Based on this result, we elucidate why certain <span><math><mi>d</mi></math></span>-dimensional spaces allow us to bypass the curse of dimensionality in nonparametric function estimation, because the convergence rates are bounded by those of the univariate case, with a logarithmic factor raised to a power determined by the dimension. Our results reveal that convergence rates with logarithmic factors are generally uniformly unimprovable.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"227 ","pages":"Article 110526"},"PeriodicalIF":0.7,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144891864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A-optimal design for Becker’s minimum polynomial with upper and lower bound constraints","authors":"Junpeng Li , Guanghui Li , Chongqi Zhang","doi":"10.1016/j.spl.2025.110534","DOIUrl":"10.1016/j.spl.2025.110534","url":null,"abstract":"<div><div>This paper investigates the <span><math><mi>A</mi></math></span>-optimal design of Becker’s minimum polynomial of order 2 with upper and lower bound constraints. It also provides the necessary results to obtain the <span><math><mi>A</mi></math></span>-optimal designs on <span><math><mi>L</mi></math></span>-simplex and <span><math><mi>U</mi></math></span>-simplex.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"227 ","pages":"Article 110534"},"PeriodicalIF":0.7,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144892979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A note on the geodesic normal distribution on the sphere","authors":"José E. Chacón , Andrea Meilán-Vila","doi":"10.1016/j.spl.2025.110532","DOIUrl":"10.1016/j.spl.2025.110532","url":null,"abstract":"<div><div>This paper presents an alternative formulation of the geodesic normal distribution on the sphere, building on the work of <span><span>Hauberg (2018)</span></span>. While the isotropic version of this distribution is naturally defined on the sphere, the anisotropic version requires projecting points from the sphere onto the tangent space. In contrast, our approach removes the dependence on the tangent space and defines the geodesic normal distribution directly on the sphere. Moreover, we demonstrate that the density contours of this distribution are exactly ellipses on the sphere, providing intriguing alternative characterizations for describing this locus of points.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"227 ","pages":"Article 110532"},"PeriodicalIF":0.7,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144908721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Limit theorems for renewal processes with infinite mean interarrival time under random inspection","authors":"Diana Rauwolf","doi":"10.1016/j.spl.2025.110527","DOIUrl":"10.1016/j.spl.2025.110527","url":null,"abstract":"<div><div>Analogues to fundamental asymptotic relations in renewal theory are considered under the assumption that the time is a random variable and that the interarrival times have infinite mean. Limits are given for interarrival times with regularly varying tail and for sequences of parameters of the respective random-time distribution under mild conditions. An application to alternating renewal processes is shown.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"227 ","pages":"Article 110527"},"PeriodicalIF":0.7,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144878116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Asymptotic behavior of finite-time ruin probabilities in a bidimensional compound risk model","authors":"Jinjin Zhang , Yang Yang , Lin Xu","doi":"10.1016/j.spl.2025.110529","DOIUrl":"10.1016/j.spl.2025.110529","url":null,"abstract":"<div><div>Consider a bidimensional compound risk model with stochastic premiums and returns, in which an insurer makes both risk-free and risky investments in two lines of business, and an accident may cause more than one claim. In this model, we allow that the two log-price processes are both real-valued Lévy processes, the claim numbers from the same business line, the two accident arrival processes and the two premium processes from two business lines are, respectively, arbitrarily dependent, and the premium processes are also arbitrarily dependent on all other random sources except the log-price processes. Under the condition that all claims from the same line are pairwise quasi-asymptotically independent and consistently varying-tailed, this paper establishes the asymptotic formulas for two types of finite-time ruin probabilities.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"227 ","pages":"Article 110529"},"PeriodicalIF":0.7,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fractional signature: A generalisation of the signature inspired by fractional calculus","authors":"José Manuel Corcuera, Rubén Jiménez","doi":"10.1016/j.spl.2025.110533","DOIUrl":"10.1016/j.spl.2025.110533","url":null,"abstract":"<div><div>In this paper, we propose a novel generalisation of the signature of a path, motivated by fractional calculus, which is able to describe the solutions of linear Caputo controlled FDEs. We also propose another generalisation of the signature, inspired by the previous one, but more convenient to use in machine learning. Finally, we test this last signature in a toy application to the problem of handwritten digit recognition, where significant improvements in accuracy rates are observed compared to those of the original signature.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"227 ","pages":"Article 110533"},"PeriodicalIF":0.7,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Space–time fractional diffusion with stochastic resetting","authors":"Priti, Arun Kumar","doi":"10.1016/j.spl.2025.110528","DOIUrl":"10.1016/j.spl.2025.110528","url":null,"abstract":"<div><div>In this article, we study the space–time fractional diffusion equation (STFDE) which is a generalization of the classical diffusion equation, in the presence of stochastic resetting. The STFDE is formulated by replacing the standard time and space derivatives with the Caputo and Riesz fractional derivatives, respectively, to capture anomalous diffusion behaviors. We derive analytical solutions using Laplace and Fourier transforms, and express them in terms of Fox H-functions. We obtain a closed-form expression for the stationary distribution and prove the finiteness of the mean first passage time. Additionally, we examine how stochastic resetting influences the infinite divisibility of the standard diffusion process, showing that this property is lost once resetting is introduced. The reset mechanism interrupts the Lévy process at random times, effectively altering the jump structure and destroying the self-decomposability required for infinite divisibility.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"227 ","pages":"Article 110528"},"PeriodicalIF":0.7,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Random bridges in spaces of growing dimension","authors":"Bochen Jin","doi":"10.1016/j.spl.2025.110530","DOIUrl":"10.1016/j.spl.2025.110530","url":null,"abstract":"<div><div>We investigate the limiting behaviour of the path of random bridges treated as random sets in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup></math></span> with the Euclidean metric and the dimension <span><math><mi>d</mi></math></span> increasing to infinity. The main result states that, in the square integrable case, the limit (in the Gromov–Hausdorff sense) is deterministic, namely, it is <span><math><mrow><mo>[</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>]</mo></mrow></math></span> equipped with the pseudo-metric <span><math><msqrt><mrow><mrow><mo>|</mo><mi>t</mi><mo>−</mo><mi>s</mi><mo>|</mo></mrow><mrow><mo>(</mo><mn>1</mn><mo>−</mo><mrow><mo>|</mo><mi>t</mi><mo>−</mo><mi>s</mi><mo>|</mo></mrow><mo>)</mo></mrow></mrow></msqrt></math></span>. We also show that, in the heavy-tailed case with summands regularly varying of order <span><math><mrow><mi>α</mi><mo>∈</mo><mrow><mo>(</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>)</mo></mrow></mrow></math></span>, the limiting metric space has a random metric derived from the bridge variant of a subordinator.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"227 ","pages":"Article 110530"},"PeriodicalIF":0.7,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A note on three new bounds of Tsallis entropy","authors":"Panxu Yuan , Zhenfeng Zou","doi":"10.1016/j.spl.2025.110524","DOIUrl":"10.1016/j.spl.2025.110524","url":null,"abstract":"<div><div>Tsallis entropy is a commonly used uncertainty measure in information theory. In this paper, three new bounds of Tsallis entropy are provided for discrete random variables with finite support. This improves the understanding of the information content in complex systems.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"227 ","pages":"Article 110524"},"PeriodicalIF":0.7,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144860661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Borel–Cantelli lemma under m-dependence","authors":"Dawei Lu, Yunpeng Shi, Junhan Zhao","doi":"10.1016/j.spl.2025.110525","DOIUrl":"10.1016/j.spl.2025.110525","url":null,"abstract":"<div><div>Let <span><math><msubsup><mrow><mrow><mo>{</mo><msub><mrow><mi>A</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>}</mo></mrow></mrow><mrow><mi>n</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>∞</mi></mrow></msubsup></math></span> be an <span><math><mi>m</mi></math></span>-dependent sequence of events. In this paper, we proved the second part of the Borel–Cantelli lemma still holds under <span><math><mi>m</mi></math></span>-dependence. Furthermore, we also obtained the quantitative version of this result.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"227 ","pages":"Article 110525"},"PeriodicalIF":0.7,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144860297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}