[erlang-questions] graphs and trees

[mats cronqvist]

  so i've made a directad acyclic graph by calling various functions in
the digraph module. i theory, the resulting graph should be a tree. is
there some snazzy graph theory trick to show that the graph is indeed a
tree?
  disclaimer; i am by training a physicist, and as such uncomfortable
with all data structures more complicated than the fixed-size array. so
no big words please :>

  mats