A class of smooth models satisfying marginal and context specific conditional independencies

作者：Colombi R; Forcina A^*

来源：Journal of Multivariate Analysis, 2014, 126: 75-85.

DOI：10.1016/j.jmva.2014.01.001

• Categorical data
• Marginal log-linear parameterizations
• Smooth parameterizations

We study a class of conditional independence models for discrete data with the property that one or more log-linear interactions are defined within two different marginal distributions and then constrained to 0; all the conditional independence models which are known to be non-smooth belong to this class. We introduce a new marginal log-linear parameterization and show that smoothness may be restored by restricting one or more independence statements to hold conditionally to a restricted subset of the configurations of the conditioning variables. Our results are based on a specific reconstruction algorithm from log-linear parameters to probabilities and fixed point theory. Several examples are examined and a general rule for determining the implied conditional independence restrictions is outlined.

• 出版日期2014-4
• 单位Perugia