2. FairFifo
3.
e,e':E. loc(e) = loc(e') 
e <c e' 
e = e' e' <c e
4.
e:E. first(e) 
(e':E. loc(e') = loc(e) 
e' <c e)
5. t :
6. 0<t
7.
i:Id.
7.
first(<i,t-1>)
7.
7. pred(<i,t-1>) <loc <i,t-1>
7. & (
e':E. (pred(<i,t-1>) <loc e' & e' <loc <i,t-1>))
8.
t = 0
9. i : Id
10. isnull(a(i;t-1))
11. first(<i,t-1>)
12.
first(<i,t-1>)
13. pred(<i,t-1>) <loc <i,t-1>
14.
e':E. (pred(<i,t-1>) <loc e' & e' <loc <i,t-1>)
15. e' : E
16. e'' : E
17. pred(<i,t-1>) = e''
18. loc(e'') = loc(e')
19. time(e'')<time(e')
20. loc(e') = i
21. time(e')<t
22. time(e') = t-1
time(e')<t-1
