English
The negation of MulDissociated is characterized by the existence of two finite subsets with equal products (and not equal as sets).
Русский
Ложность MulDissociated характеризуется существованием двух конечных подмножеств с равными произведениями (и различными как множества).
LaTeX
$$$$ \neg \mathrm{MulDissociated}(s) \iff \exists t,u:\; t,u \subseteq s \land t \neq u \land \prod t = \prod u. $$$$
Lean4
@[to_additive (attr := simp)]
theorem not_mulDissociated :
¬MulDissociated s ↔ ∃ t : Finset α, ↑t ⊆ s ∧ ∃ u : Finset α, ↑u ⊆ s ∧ t ≠ u ∧ ∏ x ∈ t, x = ∏ x ∈ u, x := by
simp [MulDissociated, InjOn]; aesop