Understanding the Role of Analytic Lemmas in Dirichlet L-Functions

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Author:

(1) Yitang Zhang.

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Table of Links

Abstract & Introduction
Notation and outline of the proof
The set Ψ1
Zeros of L(s, ψ)L(s, χψ) in Ω
Some analytic lemmas
Approximate formula for L(s, ψ)
Mean value formula I
Evaluation of Ξ11
Evaluation of Ξ12
Proof of Proposition 2.4
Proof of Proposition 2.6
Evaluation of Ξ15
Approximation to Ξ14
Mean value formula II
Evaluation of Φ1
Evaluation of Φ2
Evaluation of Φ3
Proof of Proposition 2.5

Appendix A. Some Euler products

Appendix B. Some arithmetic sums

References

5. Some analytic lemmas


The proofs of (5.3) and (5.4) are similar.


Lemma 5.2. Let ψ and s be as in Lemma 5.1. Then


Proof. The left side is


By (2.6) and the Stirling formula, for |w| < 5α,


Hence, for 1 ≤ j ≤ 3,


The result now follows since


Recall that ϑ(s) and ω(s) are given by (2.3) and (2.15) respectively. It is known that


For t > 1 we have


where


Let


and


Note that


Proof. By the Mellin transform (see [1], Lemma 2) we have


with


By the relation


and Cauchy’s theorem, the proof of (5.8) is reduced to showing that


for 1 ≤ j ≤ 5, where Lj denote the segments


This yields (5.12) with j = 3 .


As a consequence of Lemma 5.3, the Mellin transform


is analytic for σ > 0.


Lemma 5.4. (i). If 1/2 ≤ σ ≤ 2, then


(ii). If |s − 1| < 10α, then


Proof. (i). Using partial integration twice we obtain


By (5.10) we have


Thus some upper bounds for ∆′′(x) analogous to Lemma 5.3 can be obtained, and (i) follows.


Throughout the rest of this paper we assume that (A) holds. This assumption will not be repeated in the statements of the lemmas and propositions in the sequel.


The next two lemmas are weaker forms of the Deuring-Heillbronn Phenomenon.


Lemma 5.7. We have


Proof. The right side of the equality


Lemma 5.8. If


then


where


Proof. This follows from the relation



(A) and a simple bound for L ′′(w, χ).


Proof. It is known that



so that


By (9.1) and the condition |s − ρ| ≫ α for any ρ,


so that


Further, by (5.16) and Proposition 2.2 (iii),


Combining theses estimates we obtain the result. In the case σ < 1/2 the proof is analogous.


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This paper is available on arxiv under CC 4.0 license.

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