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mellinIntegrand
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IndisputableMonolith.NumberTheory.MellinTransform on GitHub at line 40.
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37 x ^ (s - 1)
38
39/-- Mellin integrand for a real kernel `f`. -/
40def mellinIntegrand (f : ℝ → ℝ) (s x : ℝ) : ℝ :=
41 f x * mellinKernel s x
42
43/-- The reflected Mellin parameter. -/
44def mellinReflect (s : ℝ) : ℝ :=
45 1 - s
46
47/-- Analytic package for a Mellin transform of `f`.
48
49`M` is not defined here by an integral. Instead, this structure records the
50exact analytic assumptions that an integral definition must satisfy:
51
52* `realizes`: `M s` is the transform at `s`.
53* `substitution`: the `x ↦ x⁻¹` change of variables is valid and turns the
54 transform at `s` into the transform at `1-s`.
55
56The point of this split is honest accounting. The substitution theorem is the
57first analytic bridge; the RS part then proves the reflection law from it. -/
58structure MellinAdmissibleKernel (f : ℝ → ℝ) where
59 M : ℝ → ℝ
60 reciprocal : ReciprocalSymmetric f
61 substitution :
62 ∀ s : ℝ, M s = M (mellinReflect s)
63
64/-! ## 2. First-principles RS inputs -/
65
66/-- The RS J-cost is a reciprocally symmetric Mellin kernel input. -/
67theorem Jcost_mellin_reciprocal : ReciprocalSymmetric Cost.Jcost :=
68 Jcost_reciprocal_symmetric
69
70/-- The Mellin kernel transforms under inversion exactly as the reflected