The local exponent at a possibly singular plane reduction, bounded by the residue-point count plus the singular correction.
theorem
CCDN.singular_reduction_minorGcd_card_bound
{s N p : ℕ}
[Fact (Nat.Prime p)]
(hs : 0 < s)
(f : MvPolynomial (Fin 2) ℤ)
(g : Fin N → MvPolynomial (Fin 2) ℤ)
(z : Fin s → Fin 2 → ℤ)
(hz : ∀ (i : Fin s), (MvPolynomial.eval (z i)) f = 0)
(hf : Irreducible ((MvPolynomial.map (Int.castRingHom (ZMod p))) f))
(hchar : f.totalDegree < p)
:
have m := Nat.card (PlaneResidue f p) + f.totalDegree ^ 2 * (f.totalDegree - 1);
0 < m ∧ ∃ (e : ℕ),
↑s ^ 2 / (2 * ↑m) - ↑s ≤ ↑e ∧ ↑p ^ e ∣ Int.Matrix.minorGcd (Matrix.of fun (i : Fin s) (k : Fin N) => (MvPolynomial.eval (z i)) (g k))
The local exponent can be bounded using the reduced point count and the proved degree-dependent singular correction.