 | next position to jump but consider empty position for null process, used in pi 
next0 :: (Num a, Ord a) => AnProcess ann -> S.Set [a]
next0 ProcessNull {} = S.singleton []
n
next0 :: (Num a, Ord a) => AnProcess ann -> S.Set [a]
next0 ProcessNull {} = S.singleton []
next0 ProcessNull {} = S.singleton []