let check_strong univ transitive graph solver p l =
let pkg_p = CudfAdd.inttovar univ p in
List.iter (fun q ->
let pkg_q = CudfAdd.inttovar univ q in
if p <> q then
if not(G.mem_edge graph pkg_p pkg_q) then
if strong_depends solver p q then
Defaultgraphs.PackageGraph.add_edge ~transitive graph pkg_p pkg_q
) l