Atomic propositions
-------------------
#define p0cs P_0.CS
#define someoneincs (in_critical==1)

Verified properties
-------------------
(1) if P_0 is in CS then it will leave it eventually
#property G(p0cs->F(!p0cs))

(2) if P_0 isn't in CS then it will eventually reach it
#property G((!p0cs)->Fp0cs)

(3) infinitely many times someone critical section
#property GFsomeoneincs

