A sharp coefficient-uniform count for geometrically irreducible affine hypersurfaces over prime fields, proved by plane-section averaging.
Numerical absorption of bad and zero plane sections above the cutoff p>27*d^4. The leading term remains exactly p^(m-1).
theorem
CCDN.affine_hypersurface_finite_field_bound
{n : ℕ}
(p : ℕ)
[Fact (Nat.Prime p)]
(f : MvPolynomial (Fin (n + 3)) (ZMod p))
(hf : Irreducible ((MvPolynomial.map (algebraMap (ZMod p) (AlgebraicClosure (ZMod p)))) f))
(hsize : stepanovThreshold ↑f.totalDegree < ↑p)
:
A geometrically irreducible affine hypersurface f = 0 in n + 3 variables over ZMod p,
with p above the threshold 27 * (deg f) ^ 4, has at most
p ^ (n + 2) + hypersurfaceResidueConstant * (deg f) ^ 2 * p ^ (n + 1) * √p points.