enrich
maplet
with
functions
. =>_ : Ref[A] → Heap[A] → Bool;
. =>? : Ref[A] → Heap[A] → Bool;
variables
o : A;
r : Ref[A];
h : Heap[A];
hP : Heap[A] → Bool;
axioms
mapex: r.=>_ = _∃(λ o. r => o);
used for: ls;
mapornull: r.=>? = (r = null ⊃ emp;r.=>_);
used for: ls;
end enrich