2. in : |R|
IdLnk
3. out : |R|
IdLnk
4. j : |R|
5.
i:|R|.
5. R(source(in(i))) & R(destination(out(i)))
5. & source(out(i)) = i
5. & & destination(in(i)) = i
5. & & in(destination(out(i))) = out(i)
5. & & out(source(in(i))) = in(i)
6.
i,j:|R|. 
k:
. 
x.destination(out(x))^k(i) = j
7. |R|
8. R(source(in(j)))
9. R(destination(out(j)))
10. source(out(j)) = j
11. destination(in(j)) = j
12. in(destination(out(j))) = out(j)
13. out(source(in(j))) = in(j)
destination(in(j)) = j 
|R|
