enrich rtc-ref ,
refset with
functions
reach : ref × (ref × ref → bool) → refset;
variables
rrp : ref × ref → bool;
axioms
reachset : ⊦ r1 ∈ reach(r0, rrp) ↔ (rrp ^*)(r0, r1);
used for : s, ls;
end enrich