Loops
We can try to unroll this into
- {P ? ? B} S {Q} ? {P ? B} S {Q ? ?B} ?{P ? B} S {Q ? B} S {Q ? ?B} ? …
But we don’t know how far to unroll, since we don’t know how many times the loop can execute
- We’re essentially looking for a fixed point of the loop
For the moment, let’s ignore the newest problem we have: dealing with termination