| ⊦ dups(y + z), a ∈ y, a ∈ z, ∃ y0, a1, z0. a ' + y + a ' + z = y0 + a1 ' + z0 ∧ a1 ∈ y0 ∧ ¬ dups(y0) |
Used simplifier rules: dups-cons: ⊦ dups(a ' + x) ↔ dups(x) ∨ a ∈ x;%app-05: ⊦ dups(x) → dups(x + y);%a: ⊦ (x + y) + z = x + y + z; from specification list% ⊦ ¬ a ∈ x → (a ∈ b ' + x ↔ a = b); (s) Used terms: a ' + y, a, z