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Proof step 201 from proof rem-stays-reachable-aux2 (previous step)

x + H[(r ' + x2).last].nxt ' = x2 + r1 ' + x3, ((r ' + x2).last ' + x0).last = (r ' + x).last, (r ' + x1).last = (r ' + x).last, path(r ' + x2 + r1 ' + x3, H), path((r ' + x2).last ' + x0, H), path(r ' + x1, H), path(r ' + x2, H), (r ' + x).last ∈ H, (r ' + x2).last ∈ H, H[(r ' + x2).last].nxt ∈ H, H[(r ' + x2).last].nxt ∈ x2 ∨ H[(r ' + x2).last].nxt = r1 ∨ H[(r ' + x2).last].nxt ∈ x3 ⊦ (r ' + x2).last = r, H[(r ' + x2).last].nxt = null, dups(x2), dups(x1), dups(x0), r ∈ x2, r ∈ x1, (r ' + x2).last ∈ x0, (r ' + x2).last ∈ x

User applied rule insert rewrite lemma

And obtained the following new goals

Proof step 202:
⊦ x0 ≠ [] → (x1 + x0).last = x0.last
Proof step 203:
x + H[x2.last].nxt ' = x2 + r1 ' + x3, (r ' + x1).last = (r ' + x).last, (x2.last ' + x0).last = (r ' + x).last, path(r ' + x2, H), path(r ' + x1, H), path(x2.last ' + x0, H), path(r ' + x2 + r1 ' + x3, H), H[x2.last].nxt ∈ H, x2.last ∈ H, (r ' + x).last ∈ H, H[x2.last].nxt ∈ x2 ∨ H[x2.last].nxt = r1 ∨ H[x2.last].nxt ∈ x3 ⊦ x2.last = r, H[x2.last].nxt = null, x2 = [], dups(x0), dups(x1), dups(x2), x2.last ∈ x, x2.last ∈ x0, r ∈ x1, r ∈ x2

Rule argument

spec: list-last, inst: reflist name: lapp seq: ⊦ x0 ≠ [] → (x1 + x0).last = x0.last subst: [x0, x1] → [x2, r '] flags: <all paths>

Additional information

Used simplifier rules: ⊦ x0 + [] = x0; (s)%a: ⊦ (x0 + x1) + x2 = x0 + x1 + x2; from specification list[reflist]% ⊦ r '.last = r; (s)% ⊦ [] + x0 = x0; (s) Used terms: x2, r '