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