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 resource_at_joins phi1 phi2 loc :
joins phi1 phi2 -> joins (phi1 @ loc) (phi2 @ loc).