English
If A and B have the same membership for all n > 0, then their Schnirelmann densities are equal.
Русский
Если множества A и B совпадают по принадлежности для всех n > 0, то их плотности Шниррельмана равны.
LaTeX
$$\\forall n>0,\\ (n \\in A \\iff n \\in B) \\Rightarrow \\operatorname{schnirelmannDensity}(A) = \\operatorname{schnirelmannDensity}(B)$$
Lean4
theorem schnirelmannDensity_congr' {B : Set ℕ} [DecidablePred (· ∈ B)] (h : ∀ n > 0, n ∈ A ↔ n ∈ B) :
schnirelmannDensity A = schnirelmannDensity B := by rw [schnirelmannDensity, schnirelmannDensity]; congr;
ext ⟨n, hn⟩; congr 3; ext x; simp_all