A finite family of distinct coordinate vectors is separated by a bounded integer linear form on the moment curve (1,t,...,t^(n-1)). The proof avoids an unquantified genericity argument.
theorem
CCDN.polynomial_exists_small_nat_eval_ne_zero
{K : Type u_1}
[Field K]
[CharZero K]
(P : Polynomial K)
(hP : P ≠ 0)
:
∃ k ≤ P.natDegree, Polynomial.eval (↑k) P ≠ 0
In characteristic zero, a nonzero polynomial P does not vanish at some natural number
k ≤ P.natDegree.
theorem
CCDN.exists_bounded_moment_separation
{K : Type u_1}
{ι : Type u_2}
[Field K]
[CharZero K]
[Fintype ι]
{n : ℕ}
(v : ι → Fin n → K)
(hv : Function.Injective v)
:
∃ k ≤ n * Fintype.card ι ^ 2, Function.Injective fun (i : ι) => ∑ j : Fin n, v i j * ↑k ^ ↑j
Bounded integer moment-curve coefficients separate every pair of a finite family of distinct vectors.