| a ' + prefixn(n, x) = prefixn(n + 1, x1), x1 = a0 + x0, a ∈ prefixn(n + 1, x1), ∀ n, x1. prefixn(n + 1, x) = prefixn(n + 1, x1) → prefixn(n, x) = prefixn(n, x1) ⊦ prefixn(n, a ' + x) = prefixn(n, x1) |
prefixn(n, x) = prefixn(n, x0), ∀ n, x1. prefixn(n + 1, x) = prefixn(n + 1, x1) → prefixn(n, x) = prefixn(n, x1) ⊦ prefixn(n, a0 ' + x) = prefixn(n, a0 ' + x0)
Used simplifier rules: ⊦ a ∈ b ' + x ↔ a = b ∨ a ∈ x; (s)% ⊦ a ' + x = b ' + y ↔ a = b ∧ x = y; (ws)%c: ⊦ m + n = n + m; from specification nat-basic%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic%a: ⊦ (x + y) + z = x + y + z; from specification list% ⊦ prefixn(n + 1, a ' + x) = a ' + prefixn(n, x); (s)% ⊦ a + x = a ' + x; (s)