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. loc(pred(<i,t-1>)) = i & time(pred(<i,t-1>))<t-1
7. & (
e':E.
7. & (
(loc(pred(<i,t-1>)) = loc(e') & time(pred(<i,t-1>))<time(e')
7. & (
(& loc(e') = i
7. & (
(& time(e')<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. loc(pred(<i,t-1>)) = i & time(pred(<i,t-1>))<t-1
14.
e':E.
14.
(loc(pred(<i,t-1>)) = loc(e') & time(pred(<i,t-1>))<time(e')
14.
(& loc(e') = i
14.
(& time(e')<t-1)
loc(pred(<i,t-1>)) = i Id & time(pred(<i,t-1>))<t
