| H[r0] .nxt = null, legal(H), r ∈ H, reachable-n(H, n0, r, r0) ⊦ r = null, reachable(r, r0, H), ∃ r0. reachable(r, r0, H) ∧ H[r0] .nxt = null |
⊦ reachable(r, r0, H) ↔ r ≠ null ∧ r ∈ H ∧ reachable*(H, r, r0)
H[r0] .nxt = null, legal(H), r ∈ H, reachable-n(H, n0, r, r0) ⊦ r = null, r ≠ null ∧ r ∈ H ∧ reachable*(H, r, r0), ∃ r0. reachable(r, r0, H) ∧ H[r0] .nxt = null
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (H, r0, r)]]