| dups((a ' + x0) -1l n), ∀ n0. ¬ dups(x0 -1l n0) ⊦ a ∈ x0, dups(x0) |
n = n1 +1, dups((a ' + x0) -1l n), ∀ n0. ¬ dups(x0 -1l n0) ⊦ a ∈ x0, dups(x0)
Used simplifier rules: delpos-base: ⊦ (a ' + x) -1l 0 = x;%nat freely generated by 0, +1;;%a: ⊦ (x + y) + z = x + y + z; from specification list