Stratified Gaussian graphical models |
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Authors: | Henrik Nyman Johan Pensar Jukka Corander |
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Affiliation: | 1. Department of Mathematics and Statistics, ?bo Akademi University, Turku, Finlandhenrik.nyman@abo.fi;3. Department of Mathematics and Statistics, ?bo Akademi University, Turku, Finland;4. Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland |
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Abstract: | Gaussian graphical models represent the backbone of the statistical toolbox for analyzing continuous multivariate systems. However, due to the intrinsic properties of the multivariate normal distribution, use of this model family may hide certain forms of context-specific independence that are natural to consider from an applied perspective. Such independencies have been earlier introduced to generalize discrete graphical models and Bayesian networks into more flexible model families. Here, we adapt the idea of context-specific independence to Gaussian graphical models by introducing a stratification of the Euclidean space such that a conditional independence may hold in certain segments but be absent elsewhere. It is shown that the stratified models define a curved exponential family, which retains considerable tractability for parameter estimation and model selection. |
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Keywords: | Bayesian model learning Context-specific independence Gaussian graphical model Multivariate normal distribution. |
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