| x0 ≠ [], ce.nxt = H[H[r0].nxt].nxt, x0.last = H[r0].nxt, path(r ' + x0, H[r0, ce]), path(r ' + x1 + r0 ', H), H[r0].nxt ∈ H, r0 ∈ H, H[r0].nxt ∈ H[r0, ce] ⊦ H[r0].nxt = ce.nxt, H[r0].nxt = null, r = r0, r = H[r0].nxt, r ∈ x0, dups(x0), r ∈ x1, r0 ∈ x1, dups(x1), ∃ x0. path(H[r0].nxt ' + x0 + H[r0].nxt ', H) ∧ ¬ r0 ∈ x0, ∃ x. path(r ' + x + H[r0].nxt ', H) ∧ ¬ r0 ∈ x |
ce.nxt = H[x0.last].nxt, x0.last = H[r0].nxt, path(r ' + x0, H[r0, ce]), path(r ' + x1 + r0 ', H), x0.last ∈ H, r0 ∈ H, x0.last ∈ H[r0, ce] ⊦ x0.last = ce.nxt, x0.last = null, r = r0, r = x0.last, x0 = [], r ∈ x0, dups(x0), r ∈ x1, r0 ∈ x1, dups(x1), ∃ x0. path(H[r0].nxt ' + x0 + H[r0].nxt ', H) ∧ ¬ r0 ∈ x0, ∃ x. path(r ' + x + x0.last ', H) ∧ ¬ r0 ∈ x