4/10 :
compare with best.pr :
- should give 2*5 +1 = 11 states
- nusmv -po gives 64 states

- are any states in beginning of phase 1 at end of phase 1 too?




--------------
Now:
- run bigger and bigger examples
- run different examples (DME)
- finish fixing up the code
- check a single example step-by-step
- collect statistical information during run
- graphical representation of the intermediate BDDs

Short term:
- look for memory leaks
- variable and process ordering
- dynamic variable ordering
- two-phase pseudo-code

Long term:
- two-phase implementation
- two-phase and saturation
- optimize generation of the transition relation
  (or measure how much time that takes)

Optimizations:
- saturation caching behavior
   - "using" computed tables 
- "union" in saturation
   - is there an efficient way of exploiting
     that lower levels are already saturated 
     (re-read how Ciardo exploits this)
- represent f1' = f1 /\ f2' = ~f2 /\ f3' = f3 as f2' = ~f2

Partial Order:
- static and dynamic partial order (or state based)
