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The local Markov condition for a DAG to be an independence map of a probability distribution is well known. For DAGs with latent variables, represented as bi-directed edges in the graph, the local Markov property may invoke exponential…

Artificial Intelligence · Computer Science 2012-07-09 Changsung Kang , Jin Tian

We introduce priors and algorithms to perform Bayesian inference in Gaussian models defined by acyclic directed mixed graphs. Such a class of graphs, composed of directed and bi-directed edges, is a representation of conditional…

Methodology · Statistics 2012-07-02 Ricardo Silva , Zoubin Ghahramani

Recent work has explored data thinning, a generalization of sample splitting that involves decomposing a (possibly matrix-valued) random variable into independent components. In the special case of a $n \times p$ random matrix with…

Methodology · Statistics 2025-12-16 Ameer Dharamshi , Anna Neufeld , Lucy L. Gao , Daniela Witten , Jacob Bien

We investigate parameter identifiability of spectral distributions of random matrices. In particular, we treat compound Wishart type and signal-plus-noise type. We show that each model is identifiable up to some kind of rotation of…

Probability · Mathematics 2021-06-07 Tomohiro Hayase

We compute analytically the probability of large fluctuations to the left of the mean of the largest eigenvalue in the Wishart (Laguerre) ensemble of positive definite random matrices. We show that the probability that all the eigenvalues…

Statistical Mechanics · Physics 2009-11-13 Pierpaolo Vivo , Satya N. Majumdar , Oriol Bohigas

It is shown that a Wishart matrix of standard complex normal random variables is asymptotically freely independent of an independent random matrix, under minimal conditions, in two different sense of asymptotic free independence.

Probability · Mathematics 2018-02-06 Arijit Chakrabarty , Sukrit Chakraborty , Rajat Subhra Hazra

A linear structural equation model relates random variables of interest and corresponding Gaussian noise terms via a linear equation system. Each such model can be represented by a mixed graph in which directed edges encode the linear…

Statistics Theory · Mathematics 2012-10-04 Rina Foygel , Jan Draisma , Mathias Drton

Our article considers a Gaussian variational approximation of the posterior density in a high-dimensional state space model. The variational parameters to be optimized are the mean vector and the covariance matrix of the approximation. The…

Methodology · Statistics 2020-02-20 Matias Quiroz , David J. Nott , Robert Kohn

The accuracy of probability distributions inferred using machine-learning algorithms heavily depends on data availability and quality. In practical applications it is therefore fundamental to investigate the robustness of a statistical…

Machine Learning · Statistics 2018-10-01 Christiane Goergen , Manuele Leonelli

A fundamental and challenging problem in spectral graph theory is to characterize which graphs are uniquely determined by their spectra. In Wang [J. Combin. Theory, Ser. B, 122 (2017): 438-451], the author proved that an $n$-vertex graph…

Combinatorics · Mathematics 2024-10-04 Wei Wang , Wei Wang , Fuhai Zhu

Covariate adjustment is a commonly used method for total causal effect estimation. In recent years, graphical criteria have been developed to identify all valid adjustment sets, that is, all covariate sets that can be used for this purpose.…

Statistics Theory · Mathematics 2022-05-11 Leonard Henckel , Emilija Perković , Marloes H. Maathuis

In this paper we consider non-asymptotic behavior of the real compound Wishart matrices that generalize the classical real Wishart distribution. In particular, we consider matrices of the form 1/nXBX', where X consists of real centered…

Applications · Statistics 2014-03-13 Ilya Soloveychik

The gamma distribution arises frequently in Bayesian models, but there is not an easy-to-use conjugate prior for the shape parameter of a gamma. This inconvenience is usually dealt with by using either Metropolis-Hastings moves, rejection…

Computation · Statistics 2018-08-01 Jeffrey W. Miller

We discuss a new leading-order parameterization of generalized parton distributions of the proton, which is based on the idea of duality. In its minimal version, the parameterization is defined by the usual quark singlet parton…

High Energy Physics - Phenomenology · Physics 2009-01-07 V. Guzey , M. V. Polyakov

We introduce a general, flexible, parametric survival modelling framework which encompasses key shapes of hazard function (constant, increasing, decreasing, up-then-down, down-then-up), various common survival distributions (log-logistic,…

Methodology · Statistics 2019-01-11 Kevin Burke , M. C. Jones , Angela Noufaily

Geostatistical modeling for continuous point-referenced data has been extensively applied to neuroimaging because it produces efficient and valid statistical inference. However, diffusion tensor imaging (DTI), a neuroimaging characterizing…

Directed acyclic graph (DAG) models are widely used to represent causal relationships among random variables in many application domains. This paper studies a special class of non-Gaussian DAG models, where the conditional variance of each…

Machine Learning · Statistics 2021-11-03 Wei Zhou , Xin He , Wei Zhong , Junhui Wang

The joint distribution of two off-diagonal Wishart matrix elements was useful in recent work on geometric probability [Finch 2010]. Not finding such formulas in the literature, we report these here.

Statistics Theory · Mathematics 2015-12-18 Steven Finch

Based on a student research project this article gives a short review on Wishart processes. A Wishart procces is a matrix valued continuous time stochastic process with a marginal Wishart distribution. The Wishart distribution is a matrix…

Probability · Mathematics 2012-01-17 Oliver Pfaffel

Modeling returns on large portfolios is a challenging problem as the number of parameters in the covariance matrix grows as the square of the size of the portfolio. Traditional correlation models, for example, the dynamic conditional…

Methodology · Statistics 2024-06-25 Lupe Shun Hin Chan , Amanda Man Ying Chu , Mike Ka Pui So