| ⊦ dups(x + set2list(s)) ↔ s ∩ list2set(x) ≠ ∅, dups(x) |
⊦ ¬ dups(x) ∧ ¬ dups(y) → (dups(x + y) ↔ list2set(x) ∩ list2set(y) ≠ ∅)
Used simplifier rules: dups: ⊦ ¬ dups(set2list(s));%set2set: ⊦ list2set(set2list(s)) = s;% ⊦ s ∩ s0 = s0 ∩ s; Used terms: set2list(s), x