Figure 3.

Graphical illustration of a Markov blanket in an ancestral graph. a) Data-generative DAG, variables H₁ and H₂ are latent. b) Corresponding ancestral graph. The set of parents, children, and spouses of T are shown in blue. Vertices connected with T or children of T by a bi-directed path and their respective parents are shown in red and are underlined. If the global Markov condition holds for the graph and joint probability distribution, a Markov blanket of T consists of vertices shown in blue and red. All grey vertices will be then independent of T conditioned on the Markov blanket.