| ∀ q, tree. p0 + q ∈ tree ↔ p0 ∈ tree ∧ q ∈ tree[p0] ⊦ (str + p0) + q ∈ tree ↔ str + p0 ∈ tree ∧ q ∈ tree[str + p0] |
∀ q, tree. p0 + q ∈ tree ↔ p0 ∈ tree ∧ q ∈ tree[p0] ⊦ (str ' + p0) + q ∈ tree ↔ str ' + p0 ∈ tree ∧ q ∈ tree[str ' + p0]
Used simplifier rules: a: ⊦ (p + p0) + p1 = p + p0 + p1; from specification list[path]% ⊦ str + p = str ' + p; (s)