| x0 ≠ [], r0 = H[r0].nxt, x0.last ∈ H, path(r0 ' + x0, H), r0 ∈ H, path(r ' + (x2 + x0.last ') + r0 ', H), path(r ' + x + x0.last ', H) ⊦ r0 = r, r0 = null, r = x0.last, r0 = x0.last, dups(x0), r0 ∈ x0, r0 ∈ x2, x0.last ∈ x2, dups(x2), r ∈ x2, x0.last ∈ x, dups(x), r ∈ x |
r0 = H[r0].nxt, x0.last ∈ H, path(r0 ' + x0, H), r0 ∈ H, path(r ' + (x2 + x0.last ') + r0 ', H), path(r ' + x + x0.last ', H) ⊦ r0 = r, r0 = null, r = x0.last, r0 = x0.last, x0 = [], dups(x0), r0 ∈ x0, r0 ∈ x2, x0.last ∈ x2, dups(x2), r ∈ x2, x0.last ∈ x, dups(x), r ∈ x