{"title":"CellMCD+: An improved outlier-resistant cellwise minimum covariance determinant method","authors":"Prabhu Babu , Petre Stoica","doi":"10.1016/j.spl.2025.110366","DOIUrl":"10.1016/j.spl.2025.110366","url":null,"abstract":"<div><div>In this letter, we revisit the recently proposed cell outlier-resistant method cellMCD (minimum covariance determinant) and derive a version of it called cellMCD+ that has better performance. We illustrate the performance gain of cellMCD+ via numerical simulations in the case of estimating low-rank structured covariance matrices.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"220 ","pages":"Article 110366"},"PeriodicalIF":0.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143202388","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":"Properties of the generalized inverse Gaussian with applications to Monte Carlo simulation and distribution function evaluation","authors":"Víctor Peña , Michael Jauch","doi":"10.1016/j.spl.2025.110359","DOIUrl":"10.1016/j.spl.2025.110359","url":null,"abstract":"<div><div>We introduce two mixture representations for the generalized inverse Gaussian (GIG) distribution. One mixture representation expresses the GIG as a continuous mixture of inverse Gaussians. The other reveals a relationship between GIGs. These mixture representations lead to new sampling methods and an exact algorithm for evaluating the distribution function of the GIG for half-integer <span><math><mi>p</mi></math></span>.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"220 ","pages":"Article 110359"},"PeriodicalIF":0.9,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135861","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":"Mean-field fractional BSDEs with locally monotone coefficients","authors":"Zongkui Fu , Dandan Fei","doi":"10.1016/j.spl.2025.110361","DOIUrl":"10.1016/j.spl.2025.110361","url":null,"abstract":"<div><div>In this paper, we study mean-field backward stochastic differential equations (BSDEs) driven by fractional Brownian motion with Hurst parameter <span><math><mi>H</mi></math></span> greater than <span><math><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math></span>. With the help of choosing the suitable approximation sequence, we obtain the existence and uniqueness of solution to mean-field fractional BSDEs with locally monotone coefficients.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"220 ","pages":"Article 110361"},"PeriodicalIF":0.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095414","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":"Poisson approximation and D(un) condition for extremes of transient random walks in random sceneries","authors":"Nicolas Chenavier, Ahmad Darwiche","doi":"10.1016/j.spl.2025.110364","DOIUrl":"10.1016/j.spl.2025.110364","url":null,"abstract":"<div><div>Let <span><math><msub><mrow><mrow><mo>(</mo><msub><mrow><mi>S</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>)</mo></mrow></mrow><mrow><mi>n</mi><mo>≥</mo><mn>0</mn></mrow></msub></math></span> be a transient random walk in the domain of attraction of a stable law and let <span><math><msub><mrow><mrow><mo>(</mo><mi>ξ</mi><mrow><mo>(</mo><mi>s</mi><mo>)</mo></mrow><mo>)</mo></mrow></mrow><mrow><mi>s</mi><mo>∈</mo><mi>Z</mi></mrow></msub></math></span> be a sequence of random variables. Under suitable assumptions, we establish a Poisson approximation result for the point process of exceedances associated with <span><math><msub><mrow><mrow><mo>(</mo><mi>ξ</mi><mrow><mo>(</mo><msub><mrow><mi>S</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>)</mo></mrow><mo>)</mo></mrow></mrow><mrow><mi>n</mi><mo>≥</mo><mn>0</mn></mrow></msub></math></span> and demonstrate that it satisfies the <span><math><mrow><mi>D</mi><mrow><mo>(</mo><msub><mrow><mi>u</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> condition.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"220 ","pages":"Article 110364"},"PeriodicalIF":0.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The asymptotic behaviors for branching α-stable process","authors":"Nana Luan , Li Wang","doi":"10.1016/j.spl.2025.110362","DOIUrl":"10.1016/j.spl.2025.110362","url":null,"abstract":"<div><div>We consider a branching symmetric <span><math><mi>α</mi></math></span>-stable process in which random split takes place at rate <span><math><mrow><mi>β</mi><mo>></mo><mn>0</mn></mrow></math></span>. We obtain results concerning the long-term behavior of the number of particles surpassing <span><math><msup><mrow><mi>e</mi></mrow><mrow><mi>λ</mi><mi>t</mi></mrow></msup></math></span> at time <span><math><mi>t</mi></math></span> for <span><math><mrow><mi>λ</mi><mo>></mo><mn>0</mn></mrow></math></span>. Additionally, we derive the almost sure asymptotic speed of the rightmost particle as a consequence.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"220 ","pages":"Article 110362"},"PeriodicalIF":0.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095415","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":"Logarithmic scale asymptotics for random walks with Weibull-like upper tail distributions","authors":"George Stoica , Deli Li","doi":"10.1016/j.spl.2025.110363","DOIUrl":"10.1016/j.spl.2025.110363","url":null,"abstract":"<div><div>We present new asymptotic results in logarithmic scale for random walks with Weibull-like upper tail distributions. The rate of convergence is essentially dictated by the stretched exponential part of the tail distribution therein.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"220 ","pages":"Article 110363"},"PeriodicalIF":0.9,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095412","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 simple consensus model for an increasing population of agents with i.i.d incoming opinions","authors":"Ioannis Markou","doi":"10.1016/j.spl.2024.110345","DOIUrl":"10.1016/j.spl.2024.110345","url":null,"abstract":"<div><div>In this short note we study what happens in a symmetric opinion model when we send the total interacting population <span><math><mrow><mi>N</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow></mrow></math></span> to infinity as <span><math><mrow><mi>t</mi><mo>→</mo><mi>∞</mi></mrow></math></span>. We assume that new population enters the system with opinions that are i.i.d random vectors with finite mean and variance. We give sharp conditions on the rate of population growth that is required for convergence to a global consensus in opinions. More particularly, we show that if the total population increases at a rate <span><math><mrow><mi>N</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow><mo>∼</mo><msup><mrow><mi>e</mi></mrow><mrow><msup><mrow><mi>t</mi></mrow><mrow><mi>α</mi></mrow></msup></mrow></msup></mrow></math></span>, then <span><math><mrow><mi>α</mi><mo><</mo><mn>1</mn></mrow></math></span> is necessary and sufficient condition for convergence to the mean of incoming opinions, and the convergence is achieved at an algebraic rate.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"220 ","pages":"Article 110345"},"PeriodicalIF":0.9,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095411","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}
Liuping Hu , Kashinath Chatterjee , Jianhui Ning , Hong Qin
{"title":"Construction of mixed-level designs with minimum discrete discrepancy","authors":"Liuping Hu , Kashinath Chatterjee , Jianhui Ning , Hong Qin","doi":"10.1016/j.spl.2025.110358","DOIUrl":"10.1016/j.spl.2025.110358","url":null,"abstract":"<div><div>Mixed-level designs are widely applicable in various practical fields. In this paper, we introduce new methods for constructing mixed-level designs with minimum discrete discrepancy. Utilizing the minimum discrete discrepancy aberration criterion, we establish a valuable analytical connection between the initial design and the resultant design, demonstrating that a high-quality initial design ensures the quality of the resultant design. Additionally, we derive general lower bounds for the discrete discrepancy, which serve as benchmarks for assessing the uniformity of mixed-level designs. Examples are provided to illustrate the effectiveness of our construction methods and the significance of the newly derived lower bounds.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"219 ","pages":"Article 110358"},"PeriodicalIF":0.9,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161085","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":"Estimation of the optimal treatment regimes with multiple treatments under proportional hazards model","authors":"Yuexin Fang , Xiangyong Tan , Qian Li","doi":"10.1016/j.spl.2025.110357","DOIUrl":"10.1016/j.spl.2025.110357","url":null,"abstract":"<div><div>We propose a novel proportional hazards model that include an unknown baseline covariate effect and the interaction between multiple treatments and covariates on censored survival data. Doubly robust estimating equations constructed by utilizing the A-learning methodology and time-dependent propensity score. The asymptotic properties of the proposed estimators are established under the correct specification of either the baseline effect model or the propensity score model. Extensive simulation studies, along with an application, demonstrate the efficacy of the proposed approach.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"219 ","pages":"Article 110357"},"PeriodicalIF":0.9,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161560","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":"Sylvester’s problem for random walks and bridges","authors":"Hugo Panzo","doi":"10.1016/j.spl.2024.110349","DOIUrl":"10.1016/j.spl.2024.110349","url":null,"abstract":"<div><div>Consider a random walk in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup></math></span> that starts at the origin and whose increment distribution assigns zero probability to any affine hyperplane. We solve Sylvester’s problem for these random walks by showing that the probability that any <span><math><mrow><mi>d</mi><mo>+</mo><mn>2</mn></mrow></math></span> consecutive steps of the walk are in convex position is equal to <span><math><mrow><mn>1</mn><mo>−</mo><mfrac><mrow><mn>2</mn></mrow><mrow><mrow><mo>(</mo><mi>d</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow><mo>!</mo></mrow></mfrac></mrow></math></span>. The analogous result also holds for random bridges of length at least <span><math><mrow><mi>d</mi><mo>+</mo><mn>2</mn></mrow></math></span> whose joint increment distribution is exchangeable.</div></div>","PeriodicalId":49475,"journal":{"name":"Statistics & Probability Letters","volume":"219 ","pages":"Article 110349"},"PeriodicalIF":0.9,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161558","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}