| ∀ n. dups(restn(n, x0)) ∧ n ≤ # x0 → dups(x0), dups(restn(n, a + x0)), n ≤ #(a + x0) ⊦ dups(a + x0) |
dups(restn(n, a ' + x0)), n ≤ # x0 + 1, ∀ n0. ¬ dups(restn(n0, x0)) ∨ ¬ n0 ≤ # x0 ⊦ a ∈ x0, dups(x0)
Used simplifier rules: rec: ⊦ dups(a ' + x) ↔ ¬ ¬(a ∈ x ∨ dups(x)); from specification list-dup%a: ⊦ (x + y) + z = x + y + z; from specification list%succ: ⊦ m +1 = m + 1; from specification nat-basic2%len-05: ⊦ #(a ' + x) = (# x)+1; from specification list%c: ⊦ a + x = a ' + x; from specification list