Author:
(1) Yitang Zhang.
Appendix A. Some Euler products
Appendix B. Some arithmetic sums
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.