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