| H[r] .nxt ∈ H, r ∈ H, reachable-n(H, m0, H[r] .nxt, r0), reachable-n(H, m + 1, r, r) ⊦ r = null, H[r] .nxt = null, reachable-n(H, m + 1, H[r] .nxt, H[r] .nxt), reachable-n(H, m + 1, r0, r0) |
⊦ reachable-n(H, n + 1, r, r0) ↔ (∃ r1. reachable-n(H, n, r, r1) ∧ reachable-1(H, r1, r0))
H[r] .nxt ∈ H, r ∈ H, reachable-n(H, m0, H[r] .nxt, r0), reachable-n(H, m + 1, r, r) ⊦ r = null, H[r] .nxt = null, ∃ r1. reachable-n(H, m, H[r] .nxt, r1) ∧ reachable-1(H, r1, H[r] .nxt), reachable-n(H, m + 1, r0, r0)
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ m + n = n + m])], [EXTRATERMS : (H[r] .nxt, H[r] .nxt, m, H)]]