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LeanPool.CarlsonFunctions.Carlson.L.Relations

Associated relations and Euler transformation for Carlson's L-function #

Carlson (1987), (3.1), (3.2), (3.4), and (2.6), in regularized form. All Dirichlet parameters and exponents are arbitrary complex numbers. In particular, the inhomogeneous lowering relation requires no division by a parameter or exponent. The proofs differentiate the corresponding R-identities.

theorem DirichletTransform.regCarlsonLContinued_eq_sum_addDirichletUnit {ι : Type u_1} [Fintype ι] (t : ℂ) (b : ι → ℂ) {z : ι → ℂ} (hz : z ∈ carlsonRVariableDomain) :
regCarlsonLContinued t z hz b = ∑ i : ι, b i * regCarlsonLContinued t z hz (addDirichletUnit b i)

Equation (3.1), after Gamma regularization.

theorem DirichletTransform.regCarlsonLContinued_add_one_eq_sum_mul_addDirichletUnit {ι : Type u_1} [Fintype ι] (t : ℂ) (b : ι → ℂ) {z : ι → ℂ} (hz : z ∈ carlsonRVariableDomain) :
regCarlsonLContinued (t + 1) z hz b = ∑ i : ι, b i * z i * regCarlsonLContinued t z hz (addDirichletUnit b i)

Equation (3.2), after Gamma regularization.

theorem DirichletTransform.regCarlsonLContinued_eq_addDirichletUnit {ι : Type u_1} [Fintype ι] (t : ℂ) (b : ι → ℂ) {z : ι → ℂ} (hz : z ∈ carlsonRVariableDomain) (i : ι) :
regCarlsonLContinued t z hz b = (∑ j : ι, b j + t) * regCarlsonLContinued t z hz (addDirichletUnit b i) - t * z i * regCarlsonLContinued (t - 1) z hz (addDirichletUnit b i) + regCarlsonRContinued t z hz (addDirichletUnit b i) - z i * regCarlsonRContinued (t - 1) z hz (addDirichletUnit b i)

Equation (3.4), with parameters raised instead of lowered. The two R-terms are essential: L is not homogeneous in the exponent-dependent coefficients.

theorem DirichletTransform.regCarlsonLContinued_euler {ι : Type u_1} [Fintype ι] (t : ℂ) (b : ι → ℂ) {z : ι → ℂ} (hz : z ∈ carlsonRVariableDomain) :
regCarlsonLContinued t z hz b = (-∏ i : ι, z i ^ (-b i)) * regCarlsonLContinued (-∑ i : ι, b i - t) (fun (i : ι) => (z i)⁻¹) ⋯ b

Equation (2.6): the Euler transformation for L has a minus sign from the reflected exponent. It holds for all complex Dirichlet parameters after regularization.