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Proof step 6 from proof rem-reachable (previous step)

ce.nxt = H[H[r1].nxt].nxt, path(r ' + x, H), r1 ∈ H, H[r1].nxt ∈ H ⊦ (r ' + x).last = H[r1].nxt, H[r1].nxt = null, r1 = null, reachable(r, (r ' + x).last, H[r1, ce])

User applied rule structural induction

And obtained the following new goals

Proof step 7:
ce.nxt = H[H[r1].nxt].nxt, path(r ' + (r0 + x0), H), H[r1].nxt ∈ H, r1 ∈ H, ∀ ce, H, r1, r. ce.nxt = H[H[r1].nxt].nxt ∧ path(r ' + x0, H) ∧ r1 ∈ H ∧ H[r1].nxt ∈ H → (r ' + x0).last = H[r1].nxt ∨ H[r1].nxt = null ∨ r1 = null ∨ reachable(r, (r ' + x0).last, H[r1, ce]) ⊦ (r ' + (r0 + x0)).last = H[r1].nxt, H[r1].nxt = null, r1 = null, reachable(r, (r ' + (r0 + x0)).last, H[r1, ce])

Rule argument

indvar: x

Additional information

Used simplifier rules: path-one: ⊦ path(r ', H) ↔ r ∈ H ∧ r ≠ null;%self-reachable: ⊦ reachable(r, r, H) ↔ r ≠ null ∧ r ∈ H;%reflist freely generated by [], +;;% ⊦ x0 + [] = x0; (s)%a: ⊦ (x0 + x1) + x2 = x0 + x1 + x2; from specification list[reflist]% ⊦ r '.last = r; (s)% ⊦ r ∈ H[r0, ce] ↔ r = r0 ∨ r ∈ H; (ws)