The relevant gcd divides the exponent
ProvedWeil.gcdDeg_dvd_rightexponential-sumsfinite-fieldsgauss-sumsnumber-theoryweil-bound
For a finite field and , divides .
Preamble
import Mathlib.NumberTheory.GaussSum import Mathlib.NumberTheory.LegendreSymbol.QuadraticChar.GaussSum import Mathlib.NumberTheory.MulChar.Lemmas import Mathlib.GroupTheory.SpecificGroups.Cyclic import Mathlib.GroupTheory.Index import Mathlib.Analysis.SpecialFunctions.Complex.CircleAddChar import Mathlib.Analysis.SpecialFunctions.Sqrt import Mathlib.Analysis.RCLike.Basic import Mathlib.Analysis.Complex.Basic import Mathlib.Algebra.Field.GeomSum import Mathlib.Algebra.Order.BigOperators.Group.Finset set_option autoImplicit false set_option linter.unusedSectionVars false set_option linter.unusedVariables false universe u_1 u_2 open AddChar MulChar Finset
Formal statement
namespace Weil
theorem gcdDeg_dvd_right : ∀ {F : Type u_1} [inst : Field F] [inst_1 : Fintype F] [inst_2 : DecidableEq F] (d : ℕ), Nat.gcd (Fintype.card Fˣ) d ∣ d := by sorry
end WeilSource
Lidl & Niederreiter, Finite Fields, 2nd ed., Cambridge, Ch. 5 (Exponential Sums), Theorems 5.4, 5.11, 5.15, 5.30, 5.38