| H[r0].nxt = H[x.last].nxt, r0 ∈ H, r0 ∈ x, path(r ' + x, H), reachable(r, r0, H), H[r0].nxt ∈ H, x.last ∈ H ⊦ H[r0].nxt = null, reachable(r0, x.last, H) |
⊦ r ∈ x0 ↔ (∃ x1, x2. x0 = x1 + (r + x2))
H[r0].nxt = H[x.last].nxt, r0 ∈ H, ∃ x1, x2. x = x1 + (r0 + x2), path(r ' + x, H), reachable(r, r0, H), H[r0].nxt ∈ H, x.last ∈ H ⊦ H[r0].nxt = null, reachable(r0, x.last, H)
Used terms: x, r0