Questions tagged [analytic-number-theory]

A beautiful blending of real/complex analysis with number theory. The study involves distribution of prime numbers and other problems and helps giving asymptotic estimates to these.

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Variants of Selberg trace formula

I am familiar with a basic case of Selberg's trace formula, in the case of quotients of upper half plane (for example, see Sections 5.1 - 5.3 of Bergeron's book). Section 5.1 describes a general setup ...
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Accelerating convergence for some double sums

I am interested in the following general double sums, for integers $a\geq 1$ and $b\geq 2$, $$Z(a,b) = \sum_{k,\ell \geq 0} \frac{2k+3}{\binom{k+2}{2}^a} \frac{2\ell+3}{(\binom{k+2}{2}+\binom{\ell+2}{...
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Explanation of a step in a preprinted work

I have been studying this preprinted paper and the references therein. I believe that there are some typos; However, since I am not an expert yet, I would like to make sure I am correct. I do not ...
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duality argument

Throughout my studying for some papers, in particular, the proof of localized Strichart estimates, I encountered the use of the duality argument I could not fully understand. The outline of the ...
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A condition on $(a_{j})_{j\in \mathbb{N}}$ so that for all $x \in \mathbb{R}$ we have $\min_{1 \leq j \leq N}\|a_{j}x\|=o(1)$

Suppose that the sequence $(a_{j})_{j \in \mathbb{N}}$ is an increasing sequence of positive integers that satisfies $$(1)\text{ }\text{ }\text{ }\text{ }\text{ }\text{ } d | a_{d}$$ and $$ (2)\text{ }...
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10 votes
1 answer
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Has this number-theoretic constant been studied?

Unless I made a mistake, the expected value of the largest exponent in the prime factorization of random positive integer (defined in the appropriate way) is $$\eta := \sum_{n=1}^\infty \Big(1-\zeta(n)...
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On probability of coprimality of a list of numbers

We know $r$ randomly chosen integers are coprime with probability $\frac1{\zeta(r)}$. Pick a bound $N$ and pick $k\lceil N^{\alpha}\rceil$ uniformly random integers in $[0,N^{\alpha+\beta}]$ where $\...
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What can be said about the primality of Zsigmondy numbers?

I am cross-posting this from math.stackexchange, as it has received upvotes but no comments/answers after a couple months. Let $\mathcal{Z}(n,a,b)=\frac{\Phi_n(a,b)}{\gcd (\Phi_n(a,b),n)}$ be the $n$-...
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5 votes
2 answers
551 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_{\...
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A question regarding Cramér's proof on prime gaps under the Riemann Hypothesis

Let $p_n$ be the $n$th prime. Assuming the Riemann hypothesis, Harald Cramér proves that $p_n-p_{n-1}\le C(\sqrt p_n \log p_n)$ for sufficiently large $n$. Is there a value known for the constant $C$ ...
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Advanced texts on analytic number theory?

So a friend of mine is very interested in analytic number theory, and is looking for resources past the basic level. He has studied analytic number theory from several books, among them are Hardy’s ...
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Non-negativity of an infinite absolutely convergent sum

The infinite sums involving mobius function and a multiplicative function has got quite interest in past. In particular, sums of the form $$\sum_{d=1}^{\infty}\frac{\mu(d)}{f(d)}$$ for mobius function ...
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4 votes
1 answer
648 views

Is there a way to specify a special kind of reciprocals of natural numbers?

Any number with of a form $\frac{1}{n}$ has a decimal with a repetend of finite length that is never longer than $n$ (provable by Dirichlet principle). (Example: $\frac{92}{99}=0.929292\ldots$ in ...
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Asymptotic behavior of the sum $\sum_{k\le x}\frac{1}{\varphi(k)}$

Suppose $x>0$ and let $f(x)=\sum_{k\le x}\frac{1}{\varphi(k)}$, where $\varphi(k)$ is the Euler totient function. It is well known that $\sum_{k\le x}\frac{1}{k}\sim\log x$. What is the asymptotic ...
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One series converges iff the other converges

In Show that $\sum\limits_pa_p$ converges iff $\sum\limits_{n}\frac{a_n}{\log n}$ converges it is said that this sequence of partial sums converges $$ \begin{split} \sum_{1<n\leq N}\frac{a_{n}}{\...
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$\lim_{x\to \infty} \left(\sum_{n\leq x} (\log n)^k/n - \int_1^x (\log t)^k/t\right) = \text{?}$

It is easy to see (by Euler-Maclaurin, say, or just by thinking of a graph) that $$\lim_{x\to \infty} \sum_{n\leq x} \frac{(\log n)^k}{n} = \int_1^x \frac{(\log t)^k}{t} + C + O\left(\frac{(\log x)^k}{...
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12 votes
5 answers
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Resources where I can find open problems in number theory along with their level of difficulty

I have completed my master's in mathematics a couple of years ago and due to very strong personal and professional reasons I couldn't get admitted to grad school despite having a good academic ...
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Convergence of zeta Euler product with additional term

Let's consider the following Euler product ($s=\sigma+it)$: $$ P(s)=\prod_{p \; \text{prime}} \frac{1}{1-p^{-s}} \; e^{-p^{-s}}$$ So for $\sigma>1$, it is clear the product converges and we have: $$...
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Reference request Re Vinogradov's ternary Goldbach proof

I believe that I.M. Vinogradov's proof of the ternary Goldbach conjecture used the observation that the number of ways $n$ can be written as a sum of three primes equals $$ \int_0^1 \sum_{p , q , r \...
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Question about the definition of divisor sum functions at 0

I was working on convolution sums of divisor sum functions, and found it very curious that some authors would define the function at 0 as: $$\sigma_k(0):= {1\over 2}\zeta(-k)$$ But I cannot understand ...
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Complexity of small near-reciprocals at $\frac34+\epsilon$ exponent - square free smooth number case

Let $q$ be large composite square free $O(\operatorname{polylog}(T))$-smooth number in $[T,2T]$ where $T$ is a parameter. According to the paper https://arxiv.org/abs/1103.2879 we can have many ...
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Complexity of small near-reciprocals at $\frac34+\epsilon$ exponent - prime power number case

Let $q=p^r$ be large prime power of prime $p$ with $q\in[T,2T]$ where $T$ is a parameter. According to the paper https://arxiv.org/abs/1103.2879 we can have many integer pairs $a,b$ satisfying $ab\...
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Complexity of small near-reciprocals at $\frac34+\epsilon$ exponent - prime number case

Let $p$ be large prime in $[T,2T]$ where $T$ is a parameter. According to the paper https://arxiv.org/abs/1103.2879 we can have many integer pairs $a,b$ satisfying $ab\equiv c\bmod p$ such that $|c|$ ...
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2 votes
1 answer
181 views

Small near-reciprocals

Let $p$ be large prime in $[T,2T]$ where $T$ is a parameter. Can we have an integer pair $a,b$ satisfying $ab\equiv c\bmod p$ such that $|c|$ is of size $O(\operatorname{polylog}(T))$ and $a,b$ are ...
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0 votes
1 answer
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Constructing an integer with small residues for two distinct primes in polynomial time

Given two primes $p,q\in[T,2T]$, how many integers $m$ of size $O(T^{3/2+\epsilon})$ are there such that the residues $m\bmod p$ and $m\bmod q$ are both $O(polylog(T))$? Looking for an answer Is it ...
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1 vote
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Simultaneous small near-reciprocals at two distinct primes

Let $p$ and $q$ be large primes in $[T,2T]$ where $T$ is a parameter. Can we have same integer pair $a,b$ satisfying $ab\equiv c'\bmod p$ and $ab\equiv c''\bmod q$ such that both $|c'|$ and $|c''|$ ...
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On general 'explicit' expression for constant term in finite sum of function of primes

Consider the following finite sum $$\sum_{p\leq x}f(p) = S(x)+C$$ Here, $f(x)$ is smooth $p$ is prime $S(x)$(=smooth+oscillation) is also a 'function'; $C$ is a constant We also know the following $$\...
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2 votes
1 answer
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The monodromy in the proof of Little Picard via Klein's $J$

First of all, my question is in the context of formalising proofs in the proof assistant Isabelle/HOL, so my questions are a bit guided by what material we have in the complex analysis library there. ...
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8 votes
2 answers
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The smallest volume possible for a lattice with integer distances?

Let $\Lambda \subset\mathbb{R}^n$ be a lattice satisfying $\|x-y\|_2^2 \in \mathbb{Z}$ for all $x,y\in\Lambda$. How small can $\text{vol}(\Lambda)=\det(\Lambda)$ be? For example, in dimension $2$, the ...
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-1 votes
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Is there an superpolynomial integral point degree $2$ family satisfying Coppersmith's bounds?

Is there an irreducible degree $2$ bivariate curve (so of genus $0$) which satisfies Coppersmith's bounds but has superpolynomial number of integral points satisfying the bounds (allowed by Falting's ...
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2 votes
2 answers
172 views

Asymptotic estimate for $\sum_{\substack{ab\le x \\ a,b\in A}}f(a)f(b)$

Suppose that $A\subseteq \mathbb{N}$ and suppose that you have an estimate of the form $$ \sum_{\substack{a\le x \\ a\in A}}f(a) \sim g(x). $$ With this information is it possible to get an asymptotic ...
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Sum of squares squared in an arithmetic progression

Let $r(n)$ be the number of ways to write $n$ as a sum of two squares and $(a,q)=1$. What is known about $$ \sum_{n \le x,n \equiv a (\text{mod} \, q)} r(n)^2 \quad? $$ I am looking for uniform ...
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-1 votes
1 answer
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Could you please confirm or deny two identities involving weighted Stirling numbers of the second kind?

In the paper [1] below, among other things, Carlitz introduced weighted Stirling numbers of the second kind $R(n,k,r)$. He also proved that the numbers $R(n,k,r)$ can be generated by \begin{equation*}%...
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4 votes
1 answer
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Generalizations of the Brun-Titchmarsh theorem

Let $\pi(x;q,a)$ count the number of primes $\leq x$ congruent to $a$ mod $q$. The Brun-Titchmarsh Theorem states that for all $q< x$, $(a,q)=1$, we have $$ \tag{1} \pi(x;q,a) \leq \frac{2x}{\...
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3 votes
1 answer
52 views

Analytic approximation of the step function in $L^p$ norm

Motivation: Euler-Maclaurin formula uses calculus to estimate discrete sums. I wonder what one can do by reverse engineering. A concrete problem I ran into is the following. Question: Let $\chi: \...
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3 votes
1 answer
214 views

Around the equation $\sigma\left(\square\right)=\text{prime}$: counterexamples or a proof for some of these conjectures

For integers $A,B\geq 1$ we define the difference $\sigma(A)\sigma(B)-\sigma(AB)$, denoting it as $[A,B]$, where $\sigma(n)=\sum_{1\leq d\mid n}d$ denotes the sum of divisors function. It is possible ...
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3 votes
0 answers
304 views

Proof of an explicit formula for $\pi_0(x)$

Let $\pi(x)$ denote the prime counting function and $$\pi_0(x) = \lim_{\epsilon \to 0} \frac{\pi(x+\epsilon)+\pi(x-\epsilon)}{2}.$$ I've seen noted in a few references the explicit formula $$\pi_0(x) =...
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9 votes
1 answer
260 views

Is $\frac{1}{L(1+it)}$ unbounded?

Let $\chi$ be a Dirichlet character and $L(s, \chi)$ be the corresponding L-function. Is $$\frac{1}{L(1+it, \chi)}$$ unbounded for $t \in \mathbb{R}$? I'm aware that this is true if $L=\zeta$, but I'm ...
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2 votes
2 answers
305 views

Estimate $ \sum_{\substack{n\leq x\\ n\in Q\\}}\log n$ and $\sum_{\substack{n\leq x\\ n\in Q\\}} n$ where $Q$ is the square-free numbers

Let $Q$ be the set of squarefree numbers. I'd like to know estimates of following sums: $$ \sum_{\substack{n\leq x\\ n\in Q\\}}\log n \qquad\text{and}\qquad \sum_{\substack{n\leq x\\ n\in Q\\}} n. $$ ...
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2 votes
2 answers
177 views

Ask for a proof of an identity involving the product of two Bernoulli numbers

It is well known that the Bernoulli numbers $B_{k}$ for $k\in\{0,1,2,\dotsc\}$ can be generated by \begin{equation*} \frac{z}{\textrm{e}^z-1}=\sum_{k=0}^\infty B_k\frac{z^k}{k!}=1-\frac{z}2+\sum_{k=1}^...
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  • 390
15 votes
0 answers
298 views

Transcendence of sum of reciprocals of factorials

For $A \subseteq \mathbb{N}$, define $\displaystyle x_A = \sum_{n \in A} \frac{1}{n!}$. It is easy to see that for every infinite $A$, $x_A$ is irrational. Question: Is there an infinite $A \subseteq \...
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4 votes
1 answer
260 views

$\zeta(s) = 1 + X^{1-s}/(s-1) + ...$?

Let $s = \sigma+ i t$ with $0\leq \sigma\leq 1$, $|t|\leq X$, where $1\leq X<2$. It is easy to use the Euler-Maclaurin formula to prove a result of the form $$\left|\zeta(s) - 1 - \frac{X^{1-s}}{s-...
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1 vote
2 answers
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Ask for a reference or a proof of an identity involving a finite sum and the Bernoulli numbers

Let $B_{n}$ for $n\ge0$ denote the Bernoulli number generated by \begin{equation*} \frac{z}{\textrm{e}^z-1}=\sum_{n=0}^\infty B_n\frac{z^n}{n!}=1-\frac{z}2+\sum_{n=1}^\infty B_{2n}\frac{z^{2n}}{(2n)!},...
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  • 390
2 votes
0 answers
90 views

Divisibility based on central binomial coefficients

For some prime $p$, it is a standard approach based on Kummer's criterion to bound the number of positive integers $n<X$ for some parameter $X$, such that $p\nmid \binom{2n}{n}$. However, if we ...
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1 vote
1 answer
118 views

How to show something is "true in mean square"?

I am looking at the conjecture, that for every $\varepsilon,B >0$, then $$\Big| \sum_{\substack{n \in \mathbb{N}\\n \leq x}} n^{-it} - \int_1^x u^{-it} du \, \Big| \leq Cx^{1/2}|t|^{\varepsilon}$$ ...
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3 votes
0 answers
153 views

$\zeta(s) = \sum_{n\leq x} n^{-s} - x^{1-s}/(1-s) + ...$ through bounded-order Euler-Maclaurin?

It is a basic classical result (Titchmarsh Thm 4.11; credited to Hardy-Littlewood) that, uniformly for $\Re s \geq \sigma_0>0$, $t\leq 6 x$ (say), $$\zeta(s) = \sum_{n\leq x} \frac{1}{n^s} - \frac{...
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2 votes
1 answer
221 views

Pólya–Vinogradov like inequality for a character sum with Euler factors

Let $M$ be a large positive integer, $d$ an odd positive integer and $f: \mathbb{Z}_{>0} \times \mathbb{Z}_{>0} \to \mathbb{R}$. For a non-principal character $\chi_d = \chi$ with modulus $d$, I ...
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8 votes
0 answers
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The *actual* size of the first quadratic non-residue

Let $p$ be an odd prime and define $n(p)$ be the smallest positive quadratic non-residue modulo $p$. By Ankeny and later effective work of Lamzouri, Li, and Soundararajan we know that under GRH one ...
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1 vote
0 answers
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Integral of $|1/\zeta(\sigma+i T)|$ (or $|(1/\zeta(\sigma+i T))^{(k)}|$) on a horizontal half-line in the left upper quadrant

Let $T_0\geq 20$. Let $L$ be the half-line from $-\infty + i T$ to (say) $-1/2 + i T$. Since $|\zeta(s)|$ is roughly proportional to $(T/2 \pi e)^\sigma$ for $s=\sigma+ i T$ on $L$, it is clear that ...
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0 votes
0 answers
122 views

An estimate of a sum

I'm looking for an estimate of this sum $\sum_{n\leq x} \frac{\mu^2(n)}{\varphi(n)}$ where $\mu$ is the Möbius function and $\varphi$ the Euler's totient function. Thanks a lot.
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