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6 votes
1 answer
292 views

Prime number theorem via large sieve type sums

We know that the prime number theorem is equivalent to the statement $$ M(x)=\sum_{n\le x}\mu(n)=o(x). $$ By using Ramanujan sums, we can write $M(x)$ as $$ M(x)=\sum_{q\le x}\sum_{\substack{0\lt a\le ...
Itachi's user avatar
  • 178
1 vote
0 answers
191 views

Prerequisites for Chen's theorem?

I am an undergraduate theoretical physics student, and I am trying to understand Chen's theorem. But when I tried to read Chen Jingrun's 1973 paper (https://www.sciengine.com/Math%20A0/doi/10.1360/...
Ben's user avatar
  • 11
2 votes
1 answer
226 views

Sieve Method works for variant question?

There are multiple results on the sieve method, and I wanted to ask about the following variant (to know if it is trivial by one of the current versions of the sieve method, or seems a challenging ...
Stijn Cambie's user avatar
7 votes
1 answer
276 views

From $\Lambda_k$ and $\Lambda$ to $\mu$ (or $\lambda$)

Let $\{a_n\}_{n=1}^\infty$, $a_n \in \mathbb{C}$, $|a_n|\leq 1$. Let $\Lambda_k = \mu \ast \log^k$; in particular, $\Lambda_1$ equals the von Mangoldt function $\Lambda$. Suppose that we have ...
H A Helfgott's user avatar
  • 20.2k
7 votes
4 answers
793 views

Must bounded sequences be well-distributed to most *composite* moduli?

Let $\{a_n\}_{n=1}^N$, $|a_n|\leq 1$. Let $Q=\sqrt{N}$. Then $a_n$ is well-distributed modulo most prime $p\leq Q$, in the following sense: $$\sum_{p\leq Q} \frac{1}{p} \left(\frac{1}{N/p} \sum_{\...
H A Helfgott's user avatar
  • 20.2k
5 votes
1 answer
750 views

Sum of reciprocals of rough numbers

Let $x$ and $y$ be given real numbers. We may suppose that $2\leqslant x \leqslant y$ and that $u:= \log(y)/\log(x)$ remains bounded in a compact set away from $1$ as $x,y\to\infty$. An integer $n$ is ...
Krishnarjun's user avatar
1 vote
0 answers
95 views

Sieve theory obstruction: prime-sparse and nearly full-differenced sets?

Let $D(A) = {|a-b| : a, b \in A}$ denote the difference set of $A \subseteq \mathbb{Z}$. A set $A \subseteq (x/2, x]$ is almost full-differenced if $|D(A)| \geq \frac{x}{2} - \log x$. Let $C_x$ denote ...
Ganesh Gayatri's user avatar
5 votes
2 answers
651 views

The twin prime problem and the Jurkat-Richert Theorem

Where does the Jurkat-Richert Theorem for linear sieves fail when applied to the twin prime problem? I'm reading the last two chapters of Additive Number Theory The Classical Bases. The Jurkat-...
Nicky's user avatar
  • 365
0 votes
1 answer
222 views

Trying to understand last part of the proof of normalized prime gap

We know that $$\liminf_{n\to\infty}{\frac{p_{n+1}-p_n}{\log p_n}}=0.$$ I'm trying to figure out the proof and I have read a lot of documents, I asked a question here. Still I can't see what's going on....
Arda Yonet's user avatar
4 votes
2 answers
479 views

Understanding the proof of Goldston–Pintz–Yíldírím's theorem

I hope this question fits the mission of this site. In "Primes in Tuples I" theorem 2 says, $$\liminf_{n\to\infty}{\frac{p_{n+1}-p_n}{\log p_n}}=0.$$ After a sieving progress you get $$h>\...
Arda Yonet's user avatar
1 vote
1 answer
160 views

Are there infinitely many primes $p$ such that $p +2$ has at most two distinct prime factors?

using lower bound sieve, one can show that there are infinitely many prime $p$ such that $p+2$ has at most four distinct prime factors [Theorem 10.2.1, 1]. Has there been any improvement of the above ...
Nicky's user avatar
  • 365
2 votes
0 answers
179 views

A Brun-Titchmarsh type result for divisor sums; asymptotic/improved bound

In Shiu's work ('A Brun-Titchmarsh theorem for multiplicative functions') he proved that if $r\le x$ is a natural number, we have $$\sum_{r<n\le x}d(n)d(n-r)\ll x\log^2x\sum_{d|r}\frac{1}{d}.$$ I ...
user avatar
4 votes
1 answer
286 views

Density of primes $p$ where $p-1$ has a prime factor exceeding $p^{2/3}$

Fouvry proved* that primes $p$ such that the greatest prime factor, $q$, of $p-1$ is greater than $p^{2/3}$ have positive density in the primes. (The sequence is A073024 in the OEIS.) Are there any ...
Charles's user avatar
  • 9,114
1 vote
1 answer
244 views

Large sieve type inequality

Let $S_x(t)=\sum_{n\le x} a_n e(nt)$, where $e(x)=e^{2\pi i x}$. Then, the large sieve inequality tells us that $$ \sum_{q\le Q} \sum_{\substack{0\lt a \lt q \\ (a,q)=1}}|S_x(a/q)|^2 \le (Q^2+4\pi x)\...
Itachi's user avatar
  • 178
1 vote
0 answers
148 views

Counting prime factors of polynomial functions

Let $\Omega(n)$ denote the number of prime factors (counted with multiplicity) of a non-zero integer $n$. For $f \in \mathbb Z[X]$ non-zero, let $$m(f) = \liminf_{n \to \infty} \Omega(f(n))$$ (1) Is $...
Jens Reinhold's user avatar
4 votes
2 answers
257 views

Sum of $\frac{1}{(\delta_1,\delta_2)}$ with congruence restrictions

In the course of my work, I encountered the following sum ($(x,y)$ stands for the GCD of $x$ and $y$): $$L(Q)=\sum_{\substack{\delta_1,\delta_2\leq Q\\\delta_1\equiv0\ (a)\\\delta_2\equiv0\ (b)}}\frac{...
Tom Glover's user avatar
3 votes
0 answers
76 views

Divisor of given order in short intervals

Is the following Open question or Conjecture already known, or eventually settled ? Open question : For sufficiently large $x$ there is at least a positive integer in the interval $[x,x+\log^2(x)]$ ...
G. Melfi's user avatar
  • 433
3 votes
1 answer
293 views

Best available bounds for $\pi(Y)-\pi(Y-X)$?

I don't know much (anything) about sieves, but as I read the section on the Selberg upper bound sieve from Greaves's Sieves in Number Theory, there is a theorem 4 which says that If $Y\ge X \ge 2$, ...
user859588's user avatar
1 vote
0 answers
94 views

Large sieve inequality-like sum without the square

Let $S(\alpha) = \sum_{n\leq N} w(n) e^{2\pi i \alpha n}$ for some function $w$ defined on $\mathbb{R}$. Suppose $\alpha_1, \ldots, \alpha_R$ are real numbers that are $\delta$-spaced modulo $1$, for ...
SJY's user avatar
  • 579
0 votes
0 answers
54 views

On the upper bound estimation of $D(N)$ in Chen Jingrun's theorem

What are the current research results on the estimation of the upper bound of $D(N)$ in Chen Jingrun's theorem? Including but not limited to Chen Jingrun's improvement 7.8342 and Wu Jie's improvement ...
RL433's user avatar
  • 1
9 votes
1 answer
825 views

Status of current research in Sieve Theory

I have done a course in Sieve Theory from the notes of Prof. Rudnick. Before this, I did 2 courses in Number Theory from the 2 volumes of Apostol. I don't have any guidance by professor as I am living ...
Arnold's user avatar
  • 793
5 votes
2 answers
701 views

Specific application of Cauchy-Schwarz and Large Sieve

Im reading a paper by Matomaki here, and the following is stated (I'm paraphrasing): "By the Cauchy-Schwarz inequality and the large sieve, we have $$\sum_{q \leq Q}\frac{q}{\phi(q)}\sum_{\...
CBagshaw's user avatar
  • 153
5 votes
1 answer
214 views

Remainder terms of congruence sums in sets of positive density

Let $\mathcal{A} \subset \mathbb{N}$ be an infinite sequence with positive density, in the sense that $$ \tag{1} \lim_{x\to\infty} \frac{|\mathcal{A} \cap x|}{x} = c > 0, $$ and define the ...
Joshua Stucky's user avatar
10 votes
0 answers
350 views

Are there are any attempts utilising sieve theory to attack the general $a p \pm 1$ problem?

It is currently an open question if there are infinitely many primes $p$ such that $2p + 1$ is prime (Sophie Germain primes) or that at least one of $24p \pm 1$ is prime. Could Zhang's method, or the ...
KStar's user avatar
  • 533
3 votes
2 answers
465 views

Least number coprime to a given integer

For a positive integer $n$ let $$f(n):=\min\{m\in \mathbb N: m>1, \gcd(m,n)=1\} .$$ Equivalently, $f(n) $ is the smallest prime not dividing $n$. Is there any upper bound literature for this? It is ...
Dr. Pi's user avatar
  • 3,062
3 votes
0 answers
232 views

Numbers made up of primes from a given set

Take a set $\mathcal P$ of primes and denote by $\langle \mathcal P\rangle $ the set of all natural numbers composed of primes from $\mathcal P$. If \[ \sum _{p\in \mathcal P}\frac {1}{p}\] converges ...
tomos's user avatar
  • 1,381
5 votes
0 answers
326 views

Counting primes, twin primes, cousin primes: unusual approach, connection to some conjectures

I am investigating the following sieve-like algorithm. Let $S_N=\{1,\dots,N\}$. For all primes $p$ with $p_0\leq p \leq M$, we remove from $S_N$ the following elements: all numbers $n\in S_N$ such ...
Vincent Granville's user avatar
13 votes
1 answer
777 views

Large sieve inequality for sparse trigonometric polynomials

Let $S(\alpha) = \sum_{n\leq N}f(n) e^{2\pi i \alpha n}$ for some arithmetic function $f$. Suppose $\alpha_1, \ldots, \alpha_R$ are real numbers that are $\delta$-spaced modulo $1$, for some $0 < \...
user152169's user avatar
3 votes
0 answers
252 views

Counting twin primes with a sieve-like algorithm

The sequence A002822, denoted as $S$, represents all the twin primes except $\{3, 5\}$. Other than that exception, $k$ and $k+2$ are twin primes iff $(k+1)/6\in S$. Let $S(N)$ be the subset of $S$ ...
Vincent Granville's user avatar
5 votes
0 answers
130 views

On Ford's "The distribution of integers with a divisor in a given interval"

Let $H(x,y,z)$ denote the number of positive integers of size at most $x$ which have a divisor in the range $(y,z]$. In his famous "The distribution of integers with a divisor in a given interval&...
Kurisuto Asutora's user avatar
6 votes
1 answer
636 views

The history and original paper of the Rosser–Iwaniec sieve

I'm trying to find Rosser's original paper where he introduces his eponymous sieve. I've already found https://arxiv.org/pdf/math/0505521 (where the reference isn't given, but where it is indicated ...
Cloudscape's user avatar
11 votes
2 answers
744 views

Improving the error term in a classic sieving problem

I'm new to asking questions on MathOverflow, so forgive me if this question is not the kind of thing to be asked here. Let $q$ be a positive integer and let $N$ be an integer with $1 \leq N \leq q$. ...
Joshua Stucky's user avatar
-1 votes
1 answer
258 views

A number theoretical identity of exponential sum

I try to understand a number theoretical identity used by Jan-Christoph Schlage-Puchta in this answer. He defined the function $$S(\alpha)=\sum_{n\leq N}\Lambda(n) e(n\alpha)$$ where $\Lambda(n)$ is ...
user267839's user avatar
  • 6,018
3 votes
0 answers
173 views

Kubilius model in higher sieve dimension?

The Kubilius model, based on the fundamental lemma of sieve theory, let us approximate the probability of events depending on the variables $X_p$, $p\leq y$, where $X_p=1$ if $p|n$ ($n$ a random ...
H A Helfgott's user avatar
  • 20.2k
1 vote
1 answer
265 views

"Halfway" approach to Landau's 4th problem (special case of Bateman-Horn)

Landau's 4th problem asks if $n^2 + 1$ is prime for infinitely many $n \in \Bbb{Z}$. It is known that $n^2 + 1$ can only be divisible by Pythagorean primes, and that for any $p$ congruent to $1 \pmod ...
Rivers McForge's user avatar
11 votes
2 answers
1k views

What is the significance of Friedlander-Iwaniec and related theorems?

On p.177 of Number Theory Revealed: A Masterclass by Andrew Granville, the author states that "One can ask for prime values of polynomials in two or more variables." (though he later ...
Favst's user avatar
  • 2,075
-3 votes
1 answer
380 views

References of research papers which lead to starting of Sieve Theory

Question - I am thinking to present one or two papers on Sieve Theory in my masters thesis. I will also present 3 other papers on Riemann Zeta Function which I have studied earlier . But I have no ...
Arnold's user avatar
  • 793
1 vote
0 answers
106 views

Sieve Theory uniform bound in Richert's Lectures on Sieves

I'm not sure how suitable this question is, but I have had no response on Mathematics Stack Exchange. My original question is here: https://math.stackexchange.com/questions/3402938/uniformity-...
VBACODER's user avatar
  • 111
0 votes
0 answers
183 views

Prime counting function estimate sieve of Eratosthenes-Legendre

I'm trying to arrive at estimate 1.17 (page 21) of Koukoulopoulos lecture notes [https://dms.umontreal.ca/~koukoulo/documents/notes/sievemethods.pdf] $$\#\{n \leq x : p|n \Rightarrow p > \sqrt{x}\}...
numbertheorylearner's user avatar
3 votes
1 answer
416 views

Primes with given Hamming weight

If I understand correctly, in the following thread Are There Primes of Every Hamming Weight? two users of the site claim that it has been already proven that, for every sufficiently large $n \in \...
Jamai-Con's user avatar
15 votes
1 answer
1k views

Why do Maynard-Tao weights succeed?

I'm attempting to understand why the Maynard-Tao weights are successful in proving bounded gaps between primes, but the GPY weights are not. These two posts do an excellent job in giving an overview ...
numbertheorylearner's user avatar
3 votes
0 answers
106 views

Friedlander-Iwaniec Flipping moduli

I am reading section 12 (Flipping Moduli) of the paper "The polynomial $X^2+Y^4$ captures its primes" by Friedlander and Iwaniec. At page 997, just below equation (12.7) we start estimating the ...
user133643's user avatar
3 votes
2 answers
386 views

Sieve bound for the sum of two squares

Let $$S(n) = \sum_{p \le n} b(n-p),$$ where $b(a)=1$ is $a$ is a sum of two squares of positive integers and $b(a)=0$ otherwise. Trivially by PNT we have $$S(n) \le \sum_{p \le n}1 \ll \frac{n}{\log n}...
toshi's user avatar
  • 130
5 votes
1 answer
189 views

Almost-prime values attained by a product of quadratic polynomials

Let $F(x) = \prod_{i=1}^{k} (a_i x +b_i)$ be a product of $k$ linear polynomials, where $a_i,b_i$ are integers. Under very reasonable conditions, it is known that a constant $C_k$ exists with the ...
Ofir Gorodetsky's user avatar
2 votes
0 answers
119 views

Almost-prime values attained by polynomials, with extra conditions

Given integers $a_1,\ldots,a_k>0$ and $b_1,\ldots,b_k$, consider the polynomial $f(x) = \prod_{i=1}^{k} (a_i x +b_i) \in \mathbb{Z}[x]$. Suppose that $\{ a_i x+b_i\}_{i=1}^{k}$ are pairwise ...
Ofir Gorodetsky's user avatar
8 votes
1 answer
1k views

Sum of divisors below threshold

Let $\sigma(n)$ denote the sum of divisors of $n$, that is, $$ \sigma(n) = \sum_{d | n} d. $$ It is known that $\sigma$ can have values as large as order $n \log \log n$. However, obviously the sum is ...
Kurisuto Asutora's user avatar
3 votes
1 answer
686 views

Use of weights in the GPY's and Tao-Maynard's work on the twin prime conjecture

I am going through James Maynard's paper, Small Gaps between Primes, and have a number of questions regarding his approach. First, I am wondering why uses weights in his approach. While I generally ...
Sultan Aitzhan's user avatar
2 votes
0 answers
120 views

Sieving the values of an arithmetic sequence which is infinitely many times $1$

I have a sequence of positive integers $a_n$ which assumes infinitely many times the value $1$. I want to estimate the cardinality of the following set: $$\#\{n\leq x : a_n>1 \text{ and } (a_n, \...
The Number Theorist's user avatar
1 vote
1 answer
356 views

Some questions about some examples in "sieve methods" in the book "Opera de Cribro" by Friedlander and Iwaniec

I am reading the book "Opera de Cribro - John B. Friedlander, Henryk Iwaniec" and in pages 5,6 I do not understand why and how they chose $X$, $A(x)$, $A_d(x)$, $g(p)$ and $r_d(x)$. any hints will be ...
asad's user avatar
  • 841
6 votes
0 answers
233 views

admissible tuples vs. prime tuples

Let $\rho^\ast(x)$ denote the maximal length of an admissible sequence in $[1,x]$, i.e. of a sequence which does not cover all the residue classes modulo any $n\geq 2$. Hensley and Richards (1974) ...
GH from MO's user avatar
  • 105k