Graph obtained from x by (1) “marrying” (inserting an undirected
ede between) all nodes that have common children, and then replacing all edges
by undirected edges. If x contains bidirected edges, then all sets of
nodes connected by a path containing only bidirected edges are treated like a
single node (see Examples).
# NOT RUN {# returns a complete graphmoralize( "dag{ x->m<-y }" )
# also returns a complete graphmoralize( "dag{ x -> m1 <-> m2 <-> m3 <-> m4 <- y }" )
# }