Vanishing maximal determinants on a standard-monomial family produce an integer auxiliary outside the original principal ideal.
theorem
CCDN.exists_standard_auxiliary_of_zero_determinants
{n N t M : ℕ}
(f : MvPolynomial (Fin n) ℚ)
(mon : Fin N → Fin n →₀ ℕ)
(hmon : Function.Injective mon)
(hstd : ∀ (j : Fin N), mon j ∈ (Ideal.span {f}).standardExponents MonomialOrder.degLex)
(hdegree : ∀ (j : Fin N), Finsupp.degree (mon j) ≤ M)
(x : Fin t → IntPoint n)
(hdet : ∀ (a : Fin N → Fin t), (evaluationMatrix mon (x ∘ a)).det = 0)
:
∃ (g : MvPolynomial (Fin n) ℤ),
g ≠ 0 ∧ ¬f ∣ (MvPolynomial.map (Int.castRingHom ℚ)) g ∧ g.totalDegree ≤ M ∧ ∀ (i : Fin t), (MvPolynomial.eval (x i)) g = 0
If mon is an injective family of N standard monomials (for the degree-lexicographic order)
of the ideal generated by f over ℚ, all of degree at most M, and every N × N evaluation
determinant of these monomials at points chosen from x vanishes, then there is a nonzero
integer polynomial g of degree at most M, vanishing at every point x i, whose image over
ℚ is not divisible by f.