On Information-Theoretic Characterizations of Markov Random Fields and Subfields

Autor: Qi Chen, Chao Chen, Raymond W. Yeung, Pierre Moulin, Ali Al-Bashabsheh
Rok vydání: 2019
Předmět:
Zdroj: IEEE Transactions on Information Theory. 65:1493-1511
ISSN: 1557-9654
0018-9448
Popis: Let $X_i, i \in V$ form a Markov random field (MRF) represented by an undirected graph $G = (V,E)$, and $V'$ be a subset of $V$. We determine the smallest graph that can always represent the subfield $X_i, i \in V'$ as an MRF. Based on this result, we obtain a necessary and sufficient condition for a subfield of a Markov tree to be also a Markov tree. When $G$ is a path so that $X_i, i \in V$ form a Markov chain, it is known that the $I$-Measure is always nonnegative and the information diagram assumes a very special structure Kawabata and Yeung (1992). We prove that Markov chain is essentially the only MRF such that the $I$-Measure is always nonnegative. By applying our characterization of the smallest graph representation of a subfield of an MRF, we develop a recursive approach for constructing information diagrams for MRFs. Our work is built on the set-theoretic characterization of an MRF in Yeung, Lee, and Ye (2002).
Databáze: OpenAIRE