On chordal phylogeny graphs

An acyclic digraph in which every vertex has indegree at most i and outdegree j is called an (i,j) for some positive integers j. Lee et al. (2017) studied the phylogeny graphs of (2,2) digraphs gave sufficient conditions necessary a to have chordal graph. Their work was motivated by problems related evidence propagation Bayesian network it useful know moral (phylogeny are theory). In this paper, we extend their work. We completely characterize graph (1,i) (i,1) digraph, respectively, any integer i. Then, study (2,j) show that D if underlying Especially, as long chordal, its not only but also planar.