| r ∈ H, legal(H), reachable-n(H, n, r, r0) ⊦ H[r0] .nxt = null, r = null, reachable-1(H, r0, H[r0] .nxt) |
⊦ reachable-1(H, r, r0) ↔ r ≠ null ∧ r0 ≠ null ∧ r ∈ H ∧ r0 ∈ H ∧ H[r] .nxt = r0
r ∈ H, legal(H), reachable-n(H, n, r, r0) ⊦ H[r0] .nxt = null, r = null, r0 ≠ null ∧ H[r0] .nxt ≠ null ∧ r0 ∈ H ∧ H[r0] .nxt ∈ H ∧ H[r0] .nxt = H[r0] .nxt
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (H[r0] .nxt, r0, H)]]