Section Machine.
Context (ge : genv).
Definition same_except_cur (m m' : Mem.mem) :=
Mem.mem_contents m = Mem.mem_contents m' /\
max_access_at m = max_access_at m' /\
Mem.nextblock m = Mem.nextblock m'.

Lemma exclusive_approx R n : exclusive_mpred R -> exclusive_mpred (approx n R).