| ⊦ ¬ dups(x) ∧ ¬ dups(y) → (dups(x + y) ↔ list2set(x) ∩ list2set(y) ≠ ∅) |
list2set(x) ∩ list2set(y) = ∅, dups(x + y) ⊦ dups(y), dups(x)
Used simplifier rules: dups-02: ⊦ ¬ dups(x + y) → list2set(x) ∩ list2set(y) = ∅;% ⊦ s ∩ s0 = s0 ∩ s;% ⊦ (s ∩ s0) ∩ s1 = s ∩ s0 ∩ s1;% ⊦ (x + y) + z = x + y + z;