Prime scaling changes the geometric bad-prime factor by at most an absolute constant. Outside the scaling prime, the homogeneous models are related by an invertible change of coordinates and a nonzero scalar.
theorem
CCDN.hypersurfaceBadPrimeFactor_scaledHomogenize_le
{n : ℕ}
(f : MvPolynomial (Fin n) ℤ)
(hf : f ≠ 0)
{p : ℕ}
(hp : Nat.Prime p)
:
hypersurfaceBadPrimeFactor (scaledHomogenize f.totalDegree (↑p) f) ≤ Real.exp 1 * hypersurfaceBadPrimeFactor (scaledHomogenize f.totalDegree 1 f)
Prime scaling preserves all geometric bad primes away from the scaling
prime, and therefore multiplies the paper's bad-prime factor by at most e.