Skip to main content

All Questions

Filter by
Sorted by
Tagged with
6 votes
2 answers
339 views

Sum of divisors and LCM in determinants

$\newcommand{\lcm}{\operatorname{lcm}}$Let $\gcd(i,j)$ and $\lcm(i,j)$ be the greatest common divisor and least common multiple of the pair of positive integers $i$ and $j$. Denote the sum of divisors ...
T. Amdeberhan's user avatar
8 votes
1 answer
355 views

The distribution of certain Galois groups

Let $f(x)$ be a polynomial of degree $d$ with integer coefficients. Let $G_p^+$ be the Galois group of the polynomial $f(x)-y$ over $\overline{\mathbb{F}}_p(y)$ and $G_p$ be the Galois group of the ...
Alexander Kalmynin's user avatar
6 votes
2 answers
1k views

Reference for universal elliptic curves

I've seen the following sentence come up in a few papers: Consider the modular curve $Y_1(N)$ and let $E$ be the universal elliptic curve over $Y_1(N)$. This comes up in Deligne's construction of ...
Adithya Chakravarthy's user avatar
2 votes
0 answers
489 views

On quasi-modular forms with integer Fourier coefficients

It is well-known that the ring $M$ of modular forms has the structure $M=\mathbb{C}[E_4,E_6]$, where $E_k$ are the Eisenstein series. It is also known that one can define the concept of quasi-modular ...
Yuji Tachikawa's user avatar
3 votes
1 answer
280 views

Computing mth power residue symbols

Let's say I have a two odd primes, $p, q$ and $K$ is the field $\mathbb{Q}(\zeta_{pq})$. Let's say $\alpha \in \mathcal{O}$ is an arbitrary element in the ring of integers of $K$, $\frak{b} \subset \...
edward cornfoot's user avatar
2 votes
0 answers
156 views

A question on terminology for sequences satisfying $\gcd(a_m,a_n)=a_{\gcd(m,n)}$

How do you refer to those sequences $\{a_{n}\}_{n \in \mathbb{Z}^{+}}$ of integers that satisfy the condition $\text{gcd}(a_{m}, a_{n}) = a_{\text{gcd}(m,n)}$ for every $(m,n) \in \mathbb{Z}^{+} \...
Jamai-Con's user avatar
5 votes
0 answers
104 views

Exponential sums with monomials with divisor-function coefficients

In their paper "Exponential Sums with Monomials," Fouvry and Iwaniec study exponential sums roughly of the form $$ \sum_{m_1 \sim M_1} \cdots \sum_{m_r \sim M_r} c_1(m_1) \cdots c_r(m_r) e\...
Joshua Stucky's user avatar
17 votes
1 answer
1k views

Catalan's constant fast convergent series

NOTE. UPDATE 2 introduces proven series for Catalan's constant that is possibly the fastest currently known. Working with some conjectured continued fractions that were published here, I have found ...
Jorge Zuniga's user avatar
  • 2,836
9 votes
1 answer
400 views

The difference between consecutive primes in arithmetic progressions

Let $\pi(x)=\sum_{p\leq x}$ denote the prime counting function. A well known result of Baker, Harman, and Pintz on prime gaps states that for $x\geq y\geq x^{0.525}$ we have that $$\pi(x+y)-\pi(x)\gg \...
Eric Naslund's user avatar
  • 11.4k
17 votes
2 answers
938 views

Has the following problem, resembling the lonely runner conjecture, been studied?

Given $n$, what is the smallest value $\delta_n$ satisfying the following: For any group of $n$ runners with constant but distinct speeds, starting from the same point and running clockwise along the ...
Arsenii Sagdeev's user avatar
1 vote
0 answers
174 views

Books about number theory and operator algebras

Does anyone know books that covers both operator algebras and number theory. Actually, a number theory books that has operator algebraic approaches.
Peg Leg Jonathan's user avatar
6 votes
1 answer
546 views

On Cramér's theorem about roots of Zeta function

Cramér proved the following theorem (see the announcement in [1] and [2]): Consider the following function: $$V(z)=\sum_k e^{\rho_kz}$$ Where $\rho_k$ runs through non trivial zeta zeros with $Im(\...
TPC's user avatar
  • 790
11 votes
1 answer
2k views

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)...
mathworker21's user avatar
  • 1,355
3 votes
0 answers
158 views

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 $n$-...
Tejas Rao's user avatar
  • 101
2 votes
0 answers
1k views

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 ...
3 votes
0 answers
221 views

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 \...
AndreyF's user avatar
  • 171
4 votes
0 answers
272 views

The Gamma-transform and $p$-adic $L$-functions

I'm currently reading the paper "On the $\mu$-invariant of the $\Gamma$-transform of a rational function" by W Sinnott. In this paper, he gives an alternate proof that $\mu=0$ for abelian ...
Adithya Chakravarthy's user avatar
3 votes
1 answer
251 views

Congruence modulo 2 for q-series

This quest arose from certain calculations with integer partitions (having distinct parts) and the corresponding values of their Dyson ranks. I would like to ask: QUESTION. Is this congruence true ...
T. Amdeberhan's user avatar
-1 votes
1 answer
162 views

Convergence to a constant or not? Reference request [closed]

Consider the function $$f(n) = \log n /(n\ \log\theta(p_n)),$$ where $\theta$ is the first Chebyshev function and $p_n$ is the $n$-th prime. Does $f$ converge to a constant as $n$ grows to infinity, ...
EGME's user avatar
  • 1,018
0 votes
0 answers
196 views

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 ...
toshi's user avatar
  • 130
4 votes
1 answer
462 views

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}{\...
Joshua Stucky's user avatar
3 votes
1 answer
418 views

Counting cubic residues mod p

Given a prime $p=3m+1$, $(p-1)/3$ of the residues mod $p$ are cubic residues. So heuristically, for any given integer $k>1$ not a perfect cube, we would expect that about 1/3 of the primes $\equiv1\...
Charles's user avatar
  • 9,114
2 votes
0 answers
150 views

Closeness of a rational approximation

What is $$p_*:=\inf\big\{p\in\mathbb R\colon\,\inf_{n\in\mathbb N}n^p\,\inf_{k\in\mathbb N} |2\sqrt{3n}-9\pi/4-k\pi|>0\big\},$$ where $\mathbb N:=\{1,2,\dots\}$? In other words, I would like to ...
Iosif Pinelis's user avatar
4 votes
1 answer
233 views

About colossally abundant numbers - reference request

This post contains three related questions: In the OEIS sequence 073751 ( https://oeis.org/A073751/ ) there is a short Mathematica program that is said to produce the prime factors of successive ...
EGME's user avatar
  • 1,018
1 vote
0 answers
192 views

Uniform distribution mod $1$ vs independence of random variables

Let $a_1, \cdots, a_k \in [0, 1)$ be real numbers such that $1, a_1, \cdots, a_k$ are independent over the rational numbers. By the Weyl equidistribution criterion in $k$-dimensions, we know that the ...
asrxiiviii's user avatar
4 votes
1 answer
206 views

Relative density of primes in certain congruence classes

In "M. B. Nathanson - Elementary Methods in Number Theory" is shown (Theorem 7.14) that if $A$ is a set of positive integers such that $\sum_{a \in A} 1 / a$ converges then the set of ...
Hhhhhhhhhhh's user avatar
  • 1,042
4 votes
1 answer
263 views

A refinment of Beck's conjecture

Let $\mathcal{O}(n)$ and $\mathcal{D}(n)$ denote the set of all integer partitions of $n$ into odd parts and distinct parts, respectively. Let $o(n)=\#\mathcal{O}(n)$ and $d(n)=\#\mathcal{D}(n)$. ...
T. Amdeberhan's user avatar
1 vote
1 answer
186 views

Connection between central factorial numbers and the Stern–Brocot tree

Consider the central factorial numbers of even indices formed by $$U(n,k)=\frac1{(2k)!}\sum_{i=0}^{2k}(-1)^i\binom{2k}i(k-i)^{2n}.$$ Let $u(n,k):=U(n,k)\mod 2$. Define the triangle of numbers $$A(r,j)=...
T. Amdeberhan's user avatar
5 votes
1 answer
210 views

Results using a certain kind of identity

Recently, I've been reading about asymptotics for smooth numbers as well as smooth numbers in arithmetic progressions. One of the ideas I find especially pleasing among some of these results is the ...
Joshua Stucky's user avatar
0 votes
0 answers
157 views

On the mean value of Dirichlet L-function

Could you please provide a link to the source? $$\sum_{\chi\neq \chi_0}\int_{0}^{T}|L(1/2+it,\chi)|^4dt\ll (qT)^{1+\varepsilon},$$ where $\chi_0$ is the principal character modulo $q$, and $L(s,\chi)$ ...
user155294's user avatar
4 votes
1 answer
271 views

The highest power of $2$ dividing a polynomial evaluated at $x=3$

Let $\nu_2(a)$ be the $2$-adic valuation of an integer $x$, i.e. the largest power $t$ such that $2^t$ divides $x$. Define the operator $D=x\frac{d}{dx}$ and the polynomial $\Phi_k(x)=\frac{x^{k+1}-1}{...
T. Amdeberhan's user avatar
1 vote
0 answers
229 views

A sum involving the Jacobi symbols

Let $n>1$ be an odd integer and let $(\frac{\cdot}{n})$ be the Jacobi symbol. For an integer $a$, define $$S_a=\sum_{x=0}^{n-1}\left(\frac{x^2-a^2}{n}\right).$$ Are there any results on the ...
Beginner's user avatar
14 votes
1 answer
424 views

Unpublished result of Rosser in Sieve Methods book

Erdős and Selfridge (1971) state that the following is "implied by an unpublished result of Rosser" which they claim appears in a forthcoming book on sieve methods by Halberstam and Richert. ...
Bjørn Kjos-Hanssen's user avatar
2 votes
0 answers
115 views

Reference request: "A result of Siegel" related to Ramanujan-Nagell type equations

Wikipedia refers to the Diophantine equation $ x^2 + D = AB^n $ as an "equation of Ramanujan–Nagell type". It also says that "A result of Siegel implies that the number of solutions in ...
Eric Nathan Stucky's user avatar
9 votes
0 answers
462 views

Who realized the finite fields $\mathbb F_{p^n}$ first? Gauss or Galois?

Let $p$ be a prime, and let $n$ be a positive integer. The finite field $\mathbb F_{p^n}$ is often called a Galois field and denoted by $\mathrm{GF}(p^n)$ by researchers on coding theory. On the other ...
Zhi-Wei Sun's user avatar
  • 15.6k
18 votes
2 answers
3k views

Only odd primes?

For $k \ge 2$, let $$u = \{\lfloor{(k - \sqrt{k})n}\rfloor : n \ge 1\}$$ $$v = \{\lfloor{(k + \sqrt{k})n}\rfloor : n \ge 1\}.$$ My computer suggests that $u$ and $v$ are disjoint if and only if $k$ is ...
Clark Kimberling's user avatar
4 votes
1 answer
239 views

Yet, another numerical variant of the Vandermonde matrix

In my earlier (soft) MO post, an elementary response was given by Ofir Gorodetsky in regard to the determinant of the symbolic counterpart to the numerical matrix $\mathbf{M}_n=(i^j-j^i)_{i,j}^{1,n}$. ...
T. Amdeberhan's user avatar
2 votes
1 answer
413 views

Resources and outstanding conjectures about the Epstein zeta function

I am looking for a reference to the Epstein zeta function. For the Riemann zeta function, there is Titchmarsh's treatment. However, I do not know of any references regarding the Epstein zeta function ...
user859588's user avatar
4 votes
0 answers
186 views

A problem in the spirit of P. Borwein's polynomials

A well-known conjecture (now a theorem) of P. Borwein (see Wang and Krattenthaler - An asymptotic approach to Borwein-type sign pattern theorems) states: For all positive integers $n$, the sign ...
T. Amdeberhan's user avatar
1 vote
0 answers
84 views

Sum of fractional parts over coprime residues

Let $q$ be a positive integer and $\theta$ a real number with $0 \leq \theta < 1$. Consider the two sums $$ S_\theta^\pm(q)=\sum_{\substack{r=1\\ (r,q)=1}}^{q-1} \left\{\theta\pm\frac{r}{q} \right\}...
Joshua Stucky's user avatar
10 votes
2 answers
849 views

Schur's proof of Hilbert's inequality: streamlining?

TL;DR: Is there a way to make Schur's (elegant) proof of Hilbert's inequality feel like less of a trick/miracle? Longer version: Let me go quickly over Schur's proof to show what I mean. Actually, let ...
H A Helfgott's user avatar
  • 20.2k
3 votes
1 answer
200 views

Maximum number of edges in a "coprime graph"

Let's define a coprime graph as a simple graph (undirected graph without any self-loops or multiple-edges) in which for all edges $(𝑢, 𝑣)$, the property $\gcd(\mathrm{degree}_u, \mathrm{degree}_v) = ...
Rashad Mammadov's user avatar
0 votes
1 answer
180 views

Name of conjectures similar to Goldbach conjecture

Consider the following """easier""" conjectures: C1. every sum of two semiprimes $n = pq + rs$, $p,q,r,s$ primes, can be expressed as $n = (a + b)/2$; with $a,b$ primes. ...
Marzio De Biasi's user avatar
-2 votes
1 answer
139 views

Congruence modulo 4 for a generating function leads to perfect squares? [duplicate]

Consider the number of integer partitions $p(n)$ of $n$ whose generating function is $$\sum_{n\geq0}p(n)\,x^n=\prod_{k\geq1}\frac1{1-x^k}.$$ Also, the number of partitions into distinct parts $Q(n)$ ...
T. Amdeberhan's user avatar
4 votes
0 answers
214 views

Maximum entropy methods for probabilistic number theory

Might there be a good survey paper on the application of maximum entropy inference for non-trivial problems in probabilistic number theory? So far I am aware of the work of Ioannis Kontoyiannis, an ...
Aidan Rocke's user avatar
  • 3,871
1 vote
1 answer
344 views

Is there a way to tie up even and "newly suggested odd" Riemann zeta values?

Define the sequence $$a_s=(-1)^{\binom{s-1}2}\left(\frac{\pi}2\right)^s\frac1{2\cdot s!}\begin{cases} s\,E_{s-1}, \qquad \text{if $s$ is odd} \\ 2^{2s}B_s, \qquad \,\,\text{if $s$ is even};\end{cases}$...
T. Amdeberhan's user avatar
1 vote
0 answers
159 views

A follow up on Bergeron's conjecture and a question

We say two polynomials satisfy $P(x)\geq Q(x)$ iff $P(x)-Q(x)$ has non-negative coefficients. Recall $(n)_q!=\prod_{j=1}^n(1-q^j)$ and the Gaussian polynomials $\binom{n}k_q=\frac{(n)_q!}{(k)_q!(n-k)...
T. Amdeberhan's user avatar
9 votes
2 answers
547 views

Primes between $x$ and $x+x^\theta$

Iwaniec [1] proved that $$ \pi(x+x^\theta)-\pi(x) < \frac{(2+\varepsilon)x^\theta}{\eta(\theta)\log x},\ x>x_0(\varepsilon,\theta). $$ with $$ \eta(\theta)=\frac{15\theta-2}{9}. $$ (Actually, he ...
Charles's user avatar
  • 9,114
2 votes
3 answers
742 views

Asking for a proof for a sum of products of binomials: an "interesting" identity?

The following identity must have received alternative proofs, including a combinatorial argument by David Callan as found at Bijections for the Identity $4^n = \sum_{k = 0}^n \binom{2k}k\binom{2(n - k)...
T. Amdeberhan's user avatar
3 votes
1 answer
248 views

number of integers $n$ with $\|n \alpha \|$ small?

Let $\alpha \in \mathbb{R}$ and $N$ a positive integer. I am interested in the quantity $$ D(\alpha, N) := \# \{ n \in [1, N]: \| n \alpha \| < 1/N \}, $$ $\| x \|$ denotes the distance to the ...
Johnny T.'s user avatar
  • 3,625

1
3 4
5
6 7
29