Doug:

is the notation in
http://edis.win.tue.nl/and-if/and-if-1.0.html
powerful enough to express our graphs?

Problem: the notation is barely readable by humans. Is intended
for exchange.

Would a general purpose NFA (or PDA) simulator be useful?

http://watson2.cs.binghamton.edu/~tools/pda/pdadoc.html

-- Karl