{"title":"Minimax estimation of smooth optimal transport maps","authors":"Jan-Christian Hütter, P. Rigollet","doi":"10.1214/20-AOS1997","DOIUrl":"https://doi.org/10.1214/20-AOS1997","url":null,"abstract":"Brenier's theorem is a cornerstone of optimal transport that guarantees the existence of an optimal transport map $T$ between two probability distributions $P$ and $Q$ over $mathbb{R}^d$ under certain regularity conditions. The main goal of this work is to establish the minimax estimation rates for such a transport map from data sampled from $P$ and $Q$ under additional smoothness assumptions on $T$. To achieve this goal, we develop an estimator based on the minimization of an empirical version of the semi-dual optimal transport problem, restricted to truncated wavelet expansions. This estimator is shown to achieve near minimax optimality using new stability arguments for the semi-dual and a complementary minimax lower bound. Furthermore, we provide numerical experiments on synthetic data supporting our theoretical findings and highlighting the practical benefits of smoothness regularization. These are the first minimax estimation rates for transport maps in general dimension.","PeriodicalId":8032,"journal":{"name":"Annals of Statistics","volume":" ","pages":""},"PeriodicalIF":4.5,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47995177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Annals of StatisticsPub Date : 2021-04-01Epub Date: 2021-04-02DOI: 10.1214/20-aos1973
Fredrik Sävje, Peter Aronow, Michael Hudgens
{"title":"AVERAGE TREATMENT EFFECTS IN THE PRESENCE OF UNKNOWN INTERFERENCE.","authors":"Fredrik Sävje, Peter Aronow, Michael Hudgens","doi":"10.1214/20-aos1973","DOIUrl":"10.1214/20-aos1973","url":null,"abstract":"<p><p>We investigate large-sample properties of treatment effect estimators under unknown interference in randomized experiments. The inferential target is a generalization of the average treatment effect estimand that marginalizes over potential spillover effects. We show that estimators commonly used to estimate treatment effects under no interference are consistent for the generalized estimand for several common experimental designs under limited but otherwise arbitrary and unknown interference. The rates of convergence depend on the rate at which the amount of interference grows and the degree to which it aligns with dependencies in treatment assignment. Importantly for practitioners, the results imply that if one erroneously assumes that units do not interfere in a setting with limited, or even moderate, interference, standard estimators are nevertheless likely to be close to an average treatment effect if the sample is sufficiently large. Conventional confidence statements may, however, not be accurate.</p>","PeriodicalId":8032,"journal":{"name":"Annals of Statistics","volume":"49 2","pages":"673-701"},"PeriodicalIF":4.5,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8372033/pdf/nihms-1683738.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39334102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Necessary and sufficient conditions for variable selection consistency of the LASSO in high dimensions","authors":"S. Lahiri","doi":"10.1214/20-AOS1979","DOIUrl":"https://doi.org/10.1214/20-AOS1979","url":null,"abstract":"This paper investigates conditions for variable selection consistency of the LASSO in high dimensional regression models and gives necessary and sufficient conditions for the same, potentially allowing the model dimension p to grow arbitrarily fast as a function of the sample size n. These conditions require both upper and lower bounds on the growth rate of the penalty parameter. It turns out that a variant of the irrepresentable Condition (IRC) of Zhao and Yu (2006), herein called the lower irrepresentable Condition (or LIRC), is determined by the lower bound considerations while the upper bound considerations lead to a new condition, called the upper irrepresentable Condition (or UIRC) in this paper. It is shown that the LIRC together with the UIRC is necessary and sufficient for the variable selection consistency of the LASSO, thereby settling a conjecture of (Zhao and Yu, 2006). Further, it is shown that under some mild regularity conditions, the penalty parameter must necessarily tend to infinity at a certain minimal rate to ensure variable selection consistency of the LASSO and that the corresponding LASSO estimators of the nonzero regression parameters can not be √ nconsistent (even for individual parameters). Thus, under fairly general conditions, the LASSO with a single choice of the penalty parameter can not achieve both variable selection consistency and √ n-consistency simultaneously. MSC 2010 subject classifications: Primary62E20; secondary 62J05.","PeriodicalId":8032,"journal":{"name":"Annals of Statistics","volume":" ","pages":""},"PeriodicalIF":4.5,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43542740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Annals of StatisticsPub Date : 2021-02-01Epub Date: 2021-01-29DOI: 10.1214/20-aos1963
Yuxin Chen, Chen Cheng, Jianqing Fan
{"title":"ASYMMETRY HELPS: EIGENVALUE AND EIGENVECTOR ANALYSES OF ASYMMETRICALLY PERTURBED LOW-RANK MATRICES.","authors":"Yuxin Chen, Chen Cheng, Jianqing Fan","doi":"10.1214/20-aos1963","DOIUrl":"10.1214/20-aos1963","url":null,"abstract":"<p><p>This paper is concerned with the interplay between statistical asymmetry and spectral methods. Suppose we are interested in estimating a rank-1 and symmetric matrix <math> <mrow> <msup><mstyle><mi>M</mi></mstyle> <mo>⋆</mo></msup> <mo>∈</mo> <msup><mi>ℝ</mi> <mrow><mi>n</mi> <mo>×</mo> <mi>n</mi></mrow> </msup> </mrow> </math> , yet only a randomly perturbed version <b><i>M</i></b> is observed. The noise matrix <b><i>M</i></b> - <b><i>M</i></b> <sup>⋆</sup> is composed of independent (but not necessarily homoscedastic) entries and is, therefore, not symmetric in general. This might arise if, for example, we have two independent samples for each entry of <b><i>M</i></b> <sup>⋆</sup> and arrange them in an <i>asymmetric</i> fashion. The aim is to estimate the leading eigenvalue and the leading eigenvector of <b><i>M</i></b> <sup>⋆</sup>. We demonstrate that the leading eigenvalue of the data matrix <b><i>M</i></b> can be <math><mrow><mi>O</mi> <mo>(</mo> <msqrt><mi>n</mi></msqrt> <mo>)</mo></mrow> </math> times more accurate (up to some log factor) than its (unadjusted) leading singular value of <b><i>M</i></b> in eigenvalue estimation. Moreover, the eigen-decomposition approach is fully adaptive to heteroscedasticity of noise, without the need of any prior knowledge about the noise distributions. In a nutshell, this curious phenomenon arises since the statistical asymmetry automatically mitigates the bias of the eigenvalue approach, thus eliminating the need of careful bias correction. Additionally, we develop appealing non-asymptotic eigenvector perturbation bounds; in particular, we are able to bound the perterbation of any linear function of the leading eigenvector of <b><i>M</i></b> (e.g. entrywise eigenvector perturbation). We also provide partial theory for the more general rank-<i>r</i> case. The takeaway message is this: arranging the data samples in an asymmetric manner and performing eigen-decomposition could sometimes be quite beneficial.</p>","PeriodicalId":8032,"journal":{"name":"Annals of Statistics","volume":"49 1","pages":"435-458"},"PeriodicalIF":4.5,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8300484/pdf/nihms-1639565.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39218981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A rule of thumb: Run lengths to false alarm of many types of control charts run in parallel on dependent streams are asymptotically independent","authors":"M. Pollak","doi":"10.1214/20-AOS1968","DOIUrl":"https://doi.org/10.1214/20-AOS1968","url":null,"abstract":"Consider a process that produces a series of independent identically distributed vectors. A change in an underlying state may become manifest in a modification of one or more of the marginal distributions. Often, the dependence structure between coordinates is unknown, impeding surveillance based on the joint distribution. A popular approach is to construct control charts for each coordinate separately and raise an alarm the first time any (or some) of the control charts signals. The difficulty is obtaining an expression for the overall average run length to false alarm (ARL2FA).We argue that despite the dependence structure, when the process is in control, for large ARLs to false alarm, run lengths of many types of control charts run in parallel are asymptotically independent. Furthermore, often, in-control run lengths are asymptotically exponentially distributed, enabling uncomplicated asymptotic expressions for the ARL2FA.We prove this assertion for certain Cusum and Shiryaev–Roberts-type control charts and illustrate it by simulations.","PeriodicalId":8032,"journal":{"name":"Annals of Statistics","volume":"49 1","pages":"557-567"},"PeriodicalIF":4.5,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47932043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Wordlength enumerator for fractional factorial designs","authors":"Yu Tang, Hongquan Xu","doi":"10.1214/20-AOS1955","DOIUrl":"https://doi.org/10.1214/20-AOS1955","url":null,"abstract":"While the minimum aberration criterion is popular for selecting good designs with qualitative factors under an ANOVA model, the minimum $beta$-aberration criterion is more suitable for selecting designs with quantitative factors under a polynomial model. In this paper, we propose the concept of wordlength enumerator to unify these two criteria. The wordlength enumerator is defined as an average similarity of contrasts among all possible pairs of runs. The wordlength enumerator is easy and fast to compute, and can be used to compare and rank designs efficiently. Based on the wordlength enumerator, we develop simple and fast methods for calculating both the generalized wordlength pattern and the $beta$-wordlength pattern. We further obtain a lower bound of the wordlength enumerator for three-level designs and characterize the combinatorial structure of designs achieving the lower bound. Finally, we propose two methods for constructing supersaturated designs that have both generalized minimum aberration and minimum $beta$-aberration.","PeriodicalId":8032,"journal":{"name":"Annals of Statistics","volume":"49 1","pages":"255-271"},"PeriodicalIF":4.5,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48338113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Correction note: “Optimal two-stage procedures for estimating location and size of the maximum of a multivariate regression function” Ann. Statist. 40 (2012) 2850–2876","authors":"E. Belitser, S. Ghosal, H. Zanten","doi":"10.1214/20-AOS1993","DOIUrl":"https://doi.org/10.1214/20-AOS1993","url":null,"abstract":"We rectify a wrongly stated fact in the paper of Belitser, Ghosal and van Zanten (Ann. Statist.40 (2012) 2850–2876).","PeriodicalId":8032,"journal":{"name":"Annals of Statistics","volume":"49 1","pages":"612-613"},"PeriodicalIF":4.5,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48716846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Correction note: Higher order elicitability and Osband’s principle","authors":"Tobias Fissler, Johanna F. Ziegel","doi":"10.1214/20-AOS2014","DOIUrl":"https://doi.org/10.1214/20-AOS2014","url":null,"abstract":"","PeriodicalId":8032,"journal":{"name":"Annals of Statistics","volume":"49 1","pages":"614-614"},"PeriodicalIF":4.5,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45392545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Convergence of covariance and spectral density estimates for high-dimensional locally stationary processes","authors":"Danna Zhang, W. Wu","doi":"10.1214/20-AOS1954","DOIUrl":"https://doi.org/10.1214/20-AOS1954","url":null,"abstract":"Covariances and spectral density functions play a fundamental role in the theory of time series. There is a well-developed asymptotic theory for their estimates for low-dimensional stationary processes. For high-dimensional nonstationary processes, however, many important problems on their asymptotic behaviors are still unanswered. This paper presents a systematic asymptotic theory for the estimates of time-varying second-order statistics for a general class of high-dimensional locally stationary processes. Using the framework of functional dependence measure, we derive convergence rates of the estimates which depend on the sample size $T$, the dimension $p$, the moment condition and the dependence of the underlying processes.","PeriodicalId":8032,"journal":{"name":"Annals of Statistics","volume":"49 1","pages":"233-254"},"PeriodicalIF":4.5,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43249786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Annals of StatisticsPub Date : 2021-02-01Epub Date: 2021-01-29DOI: 10.1214/20-aos1951
Yinqiu He, Gongjun Xu, Chong Wu, Wei Pan
{"title":"ASYMPTOTICALLY INDEPENDENT U-STATISTICS IN HIGH-DIMENSIONAL TESTING.","authors":"Yinqiu He, Gongjun Xu, Chong Wu, Wei Pan","doi":"10.1214/20-aos1951","DOIUrl":"10.1214/20-aos1951","url":null,"abstract":"<p><p>Many high-dimensional hypothesis tests aim to globally examine marginal or low-dimensional features of a high-dimensional joint distribution, such as testing of mean vectors, covariance matrices and regression coefficients. This paper constructs a family of U-statistics as unbiased estimators of the <i>ℓ</i> <sub><i>p</i></sub> -norms of those features. We show that under the null hypothesis, the U-statistics of different finite orders are asymptotically independent and normally distributed. Moreover, they are also asymptotically independent with the maximum-type test statistic, whose limiting distribution is an extreme value distribution. Based on the asymptotic independence property, we propose an adaptive testing procedure which combines <i>p</i>-values computed from the U-statistics of different orders. We further establish power analysis results and show that the proposed adaptive procedure maintains high power against various alternatives.</p>","PeriodicalId":8032,"journal":{"name":"Annals of Statistics","volume":"49 1","pages":"154-181"},"PeriodicalIF":3.2,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8634550/pdf/nihms-1737820.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39939694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}