Definition permMapJoin (pmap1 pmap2 pmap3: access_map) :=
forall b ofs,
permjoin ((pmap1 !! b) ofs) ((pmap2 !! b) ofs) ((pmap3 !! b) ofs).

Lemma permMapJoin_order:
forall p1 p2 p3
(Hjoin: permMapJoin p1 p2 p3),
forall b ofs,
Mem.perm_order'' (p3 !! b ofs) (p1 !! b ofs) /\
Mem.perm_order'' (p3 !! b ofs) (p2 !! b ofs).