Local Open Scope logic.
(******************************************  Basic lemmas about local_facts, isptr, offset_zero  ******************************************)

(******************************************  Lemmas about mapsto and mapsto_.  ******************************************)
Lemma mapsto_local_facts:
forall sh t v1 v2,  mapsto sh t v1 v2 |-- !! (isptr v1 /\ tc_val' t v2).