let lvh_equals lvh1 lvh2 =
if not(LvExpHash.length lvh1 = LvExpHash.length lvh2)
then false
else LvExpHash.fold (fun lv e b ->
if not b then b else
try let e2 = LvExpHash.find lvh2 lv in
if not(compareExpStripCasts e e2)
then false
else true
with Not_found -> false)
lvh1 true