∀ m, m0. m + m0 < # x0 → (x0 from m)[m0] = x0[m + m0] ∨ x0 = [], m + m0 < #(a + x0) ⊦ (a + x0 from m)[m0] = (a + x0)[m + m0], a + x0 = []
Used simplifier rules: list freely generated by [], +;;