Minimal Markov blanket under faithfulness
= Minimal Markov blanket under faithfulness
Under <faithfulness of a directed acyclic graph>, every conditioning set screening a vertex from all remaining vertices contains its graphical <Markov blanket>. A missing adjacent vertex leaves a one-edge active path; a missing other parent of a child leaves the active path $k\to h\leftarrow u$, since the child $h$ is necessarily conditioned. Thus the graphical blanket is the unique smallest screening set.