Coefficient of a product of finite single-coordinate monomial sums
ProvedOAI.PiExponent.FinitePeriodCollision.coeff_prod_single_coordinate_monomial_sumirrationality-measurenumber-theoryopenai-pi-exponent-017
The coefficient of a product of finite single-coordinate monomial sums is the product of the requested coefficients, with zero whenever a requested exponent is absent.
Preamble
import Mathlib.Algebra.MvPolynomial.Basic open scoped BigOperators
Formal statement
theorem OAI.PiExponent.FinitePeriodCollision.coeff_prod_single_coordinate_monomial_sum
{σ : Type} [Fintype σ] [DecidableEq σ] {R : Type} [CommSemiring R]
(S : σ → Finset ℕ) (c : σ → ℕ → R) (A : σ → ℕ) :
(∏ i, ∑ n ∈ S i,
MvPolynomial.monomial (Finsupp.single i n) (c i n)).coeff
(Finsupp.equivFunOnFinite.symm A) =
∏ i, if A i ∈ S i then c i (A i) else 0 := by sorrySource