# Questions tagged [nt.number-theory]

Prime numbers, diophantine equations, diophantine approximations, analytic or algebraic number theory, arithmetic geometry, Galois theory, transcendental number theory, continued fractions

15,637
questions

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111
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### Does there exist an $L$-function for any subset of $\mathbb{N}$?

Consider the following prime sum:
\begin{aligned}
\sum _{p}{\frac {\cos(x\log p)}{p^{1/2}}}
\end{aligned}
whose spikes appear at the Riemann $\zeta$ zeros as shown here.
Taking these detected spikes (...

0
votes

0
answers

160
views

### Is the integer factorization into prime numbers normally distributed?

Let $P_1(n) := 1$ if $n=1$ and $\max_{q|n, \text{ }q\text{ prime}} q$ otherwise, denote the largest prime divisor of $n$.
Let us define some rooted trees $T_{n,m}$ for $1 \le m \le n$ by:
$T_{n,m}$ ...

3
votes

0
answers

46
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### $R$-recursion for the A249833 (similar to A235129)

Let $a(n)$ be A249833 i.e. an integer sequence such that its exponential generating function $A(x)$ satisfies
$$
A(x) = 1 + \int A(x) + (A(x))^2\log A(x)\,dx
$$
The sequence begins with
$$
1, 1, 2, 7, ...

2
votes

0
answers

100
views

### Computing the Dieudonné module of $\mu_p$ from Fontaine's Witt Covector

In Groupes $p$-divisibles sur les corps locaux, Fontaine introduced a uniform construction of Dieudonné modules through the definition of the Witt covector. Consider a perfect field $k$ of ...

0
votes

0
answers

172
views

### On fifth powers forming a Sidon set

We call a set of natural numbers $\mathcal S$ to be a Sidon Set if $a+b=c+d$ for $a,b,c,d\in \mathcal S$ implies $\{a,b\}=\{c,d\}$. In other words, all pairwise sums are distinct.
Erdős conjectured ...

0
votes

0
answers

98
views

### What is the logic behind the Extended Euclidean Algorithm procedure? [closed]

Thank you beforehand for reading my question.
In the terms that I'd want to understand the Extended version of the Euclidean Algorithm, I understand the Euclidean Algorithm as follows:
You find the ...

0
votes

1
answer

179
views

### Is there any use of logarithmic derivatives of modular forms?

Does taking the logarithmic derivative of a modular form have any uses, such as identifying patterns in its coefficients or possible zeros of its corresponding L function?

4
votes

1
answer

240
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### Is there an elliptic curve analogue to the 4-term exact sequence defining the unit and class group of a number field?

Let $K$ be a number field. One has the following exact sequence relating the unit group and ideal class group $\text{cl}(K)$:
$$1\to \mathcal{O}_K^\times\to K^\times \to J_K\to \text{cl}(K)\to 1$$
...

4
votes

0
answers

76
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### Buchi's conditional proof of the non-existence of finite algorithm to decide solubility of system of diagonal quadratic form equations in integers

I am doing some literature review regarding Buchi's problem. In particular, I am reading the relevant section in this survey paper by Mazur (Questions of Decidability and Undecidability in Number ...

4
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0
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107
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### Taking integer values of a sequence of Beurling primes

Let $P=(p_j)_{j=1}^\infty$ be an increasing sequence of real numbers with $1<p_1$ and $\lim_{j\to\infty}p_j=\infty$. As mentioned in [1], Beurling proved that if the multiplicative group $N_P$ ...

0
votes

0
answers

131
views

### what is the current best estimation for the upper bound of the exponential sum for an arbitrary irrational number $\alpha$

I would like to know what the current best estimation for the upper bound of the exponential sum
$$\left|\sum_{n=1}^N \exp \left(2 \pi i\alpha\left(x_0+x_1 n+\ldots+x_d n^d\right)\right)\right|=\left|\...

2
votes

1
answer

187
views

### '$\times$' or '$\otimes$' when writing $L$-functions?

Recently, I came across the Langlands correspondence theorem, there is the following line:
$$L(s,\pi(\sigma) \times \pi(\tau)) = L(s,\sigma \otimes \tau), $$
where $\sigma$ and $\tau$ are ...

2
votes

0
answers

84
views

### $R$-recursion for the A235129

Let $a(n)$ be A235129 i.e. an integer sequence such that its exponential generating function $A(x)$ satisfies
$$
A'(x) = 1 + A(x)\exp(A(x))
$$
The sequence begins with
$$
1, 1, 3, 12, 64, 424, 3358, ...

6
votes

0
answers

381
views

+50

### Genus of a number field

I'm reading Algebraic Number Theory by Neukirch. In chapter 3, he defines the genus of a number field as
$$ g = \log \frac{ |\mu (K)| \sqrt{|d_K|}}{2^{r} (2\pi)^{s}} $$ where $|\mu(K)|$ is its ...

-6
votes

0
answers

125
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### How is research on Modular Forms usually conducted? [closed]

I have just started working on modular forms through an introductory course and let led me to think how is research on them conducted. For example, what exactly do you research about modular forms, is ...

4
votes

0
answers

121
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### Sequence of digits of powers of two

Elementary number theory tells us a lot about the final digits of the powers of two, and ergodic theory (more specifically the theory of equidistribution of points in the orbit of an irrational ...

2
votes

0
answers

159
views

### Can all modular forms be written as Eta Quotients?

I have been going through a couple of introductory courses in modular forms and am quite curious whether all modular forms can be written as eta quotients of the Dedekind eta function?

5
votes

0
answers

209
views

### Video abstracts for mathematical papers

I recently published a video abstract of a manuscript of mine (number theory), finding that more people are interested in its content than when I uploaded the preprint on arXiv.
Now, my main question ...

5
votes

2
answers

391
views

### On the number of distinct prime factors of $p^2+p+1$

Is it true that, for each positive integer $c$, there exists a prime number $p$ such that $p^2+p+1$ is divisible by at least $c$ distinct primes?

3
votes

0
answers

81
views

### Is there a closed form for the Rudin-Shapiro sequence?

The Rudin-Shapiro sequence is defined as follows:
Let $a_n=\sum\epsilon_i\epsilon_{i+1}$ where $\epsilon_1,\epsilon_2...$ are the digits in the binary expansion of $n$. $WS(n)$, the $n$th term of the ...

4
votes

2
answers

537
views

### Computing hypergeometric function at 1

I'm looking to compute
$${}_ 3F_ 2\biggl(\begin{matrix} -m-1/2,\ -m,\ k-m+1/2 \cr
1/2-m,\ k-m+3/2\end{matrix};1\biggr)$$
for $m,k > 0$ are positive integers and $0 < k < m$. I'm wondering if ...

3
votes

0
answers

82
views

### A question on the averages of Kloosterman sums

Sorry to disturb. Recently, I encountered a puzzle on the sums involving two Kloosterman sums. That is,
For any $h, q_1,q_2\in \mathbb{N}$ with $(q_1,q_2)=1$ and $Q>1$, how two get a bound
$$\sum_{...

8
votes

1
answer

586
views

### Does this partial sum over primes spike at all zeta zeros?

Below is a plot of $\exp \sum _p^x -\frac{\cos \left(x \log \
p\right)}{\sqrt{p}}$, where $p$ runs over the primes, and the $x$-values of the Riemann $\zeta$ zeros are marked with dashed lines:
Below ...

0
votes

0
answers

57
views

### Decrease of $(1/\zeta)^{(r)}(\sigma + i T)$ as $\sigma\to -\infty$?

What is a standard reference for the simple fact that, for $T$ fixed and $\sigma\to -\infty$,
every derivative $|(1/\zeta)^{(r)}(\sigma+i T)|$ of the Riemann zeta function decreases faster than any ...

2
votes

0
answers

109
views

### Can K$_3$ of finite fields be related to Teichmüller cocycles?

This is sort of a blind shot, but...
For a ring $R$, its third algebraic K-group is given by $\operatorname K_3(R)=H_3(\operatorname{St}(R))$.
To simplify matters, let $R$ be a finite field $\mathbb ...

8
votes

1
answer

580
views

### Arithmetic sequences and Artin's conjecture

(Sorry if this is a naive question; it is not my area!)
Consider the following strengthening of Artin's conjecture on primitive roots (and Dirichlet's theorem) for the case of $n=2$: every arithmetic ...

-1
votes

0
answers

359
views

### Are these finite semirings known?

I am trying to prove the properties below, and by doing this, I hope to find a way to speed up the computation of the below defined addition and multiplication. I am also interested if these finite ...

3
votes

0
answers

85
views

### Meaning of dagger cohomology $H^{1 \dagger}(G^\dagger)$ in "Frobenius and Monodromy Operators" by Coleman and Iovita

Let $G$ be an abelian variety with good reduction over a finite extension $K$ of $\mathbb{Q}_p$. In equation (2.4) on page 179 of my edition of "The Frobenius and monodromy operators for curves ...

-4
votes

0
answers

189
views

### EC primes the heuristic says something different from the reality [closed]

Ec-primes are primes of the form $(2^n-1)\cdot 10^d+2^{n-1}-1=ec(n)$, where d Is the Number of decimal digits of $2^{n-1}$.
Up to $n=10^5$, there are 30 primes of this type.
A rough heuristic says 18 ...

2
votes

2
answers

242
views

### $L^1$ norm for a product of cosines

Let $k$ be an integer and consider the function
$$
f(t)=\prod_{i=1}^{k} \cos(3^{i-1}\pi t).
$$
I'm interested in finding bounds for $\int_{0}^{1}|f(t)|dt$ in terms of $k$. The first idea that comes to ...

2
votes

0
answers

41
views

### Simultaneous computation of the three Weber modular functions

Recall that the three classical Weber modular functions are defined by
$f(\tau)=e^{-\pi i/24}\eta((\tau+1)/2)/\eta(\tau)$,
$f_1(\tau)=\eta(\tau/2)/\eta(\tau)$, and
$f_2(\tau)=\sqrt{2}\eta(2\tau)/\eta(\...

5
votes

0
answers

469
views

### Theorem 7.11 in Scholze's $p$-adic Hodge Theory

I was trying to understand the statement and proof of Theorem 7.11 in Scholze's paper "$p$-adic Hodge Theory for Rigid-Analytic Varieties". I'll reproduce part of the statement below:
Let $...

2
votes

2
answers

569
views

### Can any Hurwitz zeta function be written as an Euler product?

I am attempting to understand the behavior of Hurwitz zeta functions and for what $a$ do they have an analytic continuation. Is it possible to write any Hurwitz zeta as an Euler product or are there ...

1
vote

1
answer

95
views

### Existence of tamely ramified tower of extension over $\mathbb{Q}_p$

Let $p$ be a prime. There exist following containment : $$\mathbb{Q}_p \subset \mathbb{Q}_p^{\rm nr} \subset \mathbb{Q}_p^{\rm tr} \subset \overline{\mathbb{Q}}_p$$
Here $\mathbb{Q}_p^{\rm nr}$ and $\...

6
votes

2
answers

601
views

### Number of divisors which are at most $n$

I’m interested in the function $\tau_n:\mathbb{N}\to\{1,2,3,\cdots, n\}$ defined by
$$\tau_n(x)=\sum_{k=1}^n \mathbf{1}_{k\mid x},$$
the number of divisors of $x$ which are at most $n$. Question 6 of ...

4
votes

0
answers

240
views

### An algebraic version of the implicit function theorem for integers

$ \def \x {\boldsymbol x}
\def \a {\boldsymbol a}
\def \Z {\mathbb Z} $
The famous version of the implicit function theorem (IFT) starts with the assumption of continuous differentiability on the ...

5
votes

1
answer

339
views

### Closed-form for the number of partitions of $n$ avoiding the partition $(4,3,1)$

Let $a(n)$ be A309099 i.e. the number of partitions of $n$ avoiding the partition $(4,3,1)$.
We say a partition $\alpha$ contains $\mu$ provided that one can delete rows and columns from (the Ferrers ...

9
votes

1
answer

361
views

### How fast can elliptic curve rank grow in towers of number fields?

Fix $E/K$ an elliptic curve over a number field $K$. For various towers of finite field extensions $K=K_0 \subset K_1 \subset K_2\subset\cdots$ how fast can $\operatorname{rank}(E(K_n))$ grow in ...

0
votes

0
answers

110
views

### Roots in indefinite lattice of K3 surfaces

Anyone who likes $K3$ surfaces cares about lattices of the form $$ (2d)\cdot y^2 - 2x \cdot z$$ (namely the mukai pairing on $H^*_{alg}(K3)$ of picard $1$ with polarization $d$).
Inside we have ...

2
votes

1
answer

119
views

### Cusp forms of weight 2 and level $\Gamma_0(p)$ where $p < 11$

Using Hida theory, we can prove that there is a cusp form of weight 2 and level $\Gamma_0(11)$. Are there ways to prove that there is no cusp forms of weight 2 and level $\Gamma_0(p)$ where $p < 11$...

2
votes

1
answer

181
views

### Generating function over primes in an arithmetic progression

Given a newform $\sum_{n=1}^{\infty}a(n)q^n$. Is the generating function
$$
\sum_{p\equiv a\pmod{m}}a(p)q^p
$$
over the primes $p\equiv a\pmod{m}$ still a modular form? Any help is highly appreciated! ...

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votes

0
answers

98
views

### Is it possible to write any Dirichlet series as a sum of reciprocals of arithmetic progressions? Where the Dirichlet character is primitive and real?

I was wondering since Dirichlet series can often be written as a subtraction or addition of sums of reciprocals of sequences, could you propose such a definition of a Dirichlet series, for any ...

2
votes

0
answers

57
views

### Elementary recursion for the A258173

Let $a(n)$ be A258173 i.e. sum over all Dyck paths of semilength $n$ of products over all peaks $p$ of $y_p$, where $y_p$ is the $y$-coordinate of peak $p$.
A Dyck path of semilength $n$ is a $(x,y)$-...

2
votes

0
answers

128
views

### Zeta zeros and prolate wave operators

Recently, Connes, Consani and Moscovici in https://arxiv.org/abs/2310.18423 have blended two of their results on zeta zeros and the prolate wave operators, which, they say, "suggests the ...

0
votes

1
answer

238
views

### Factorization trees and (continued) fractions?

This question is inspired by trying to understand the lexicographic sorting of the natural numbers in the fractal at this question:
Is $1 = \sum_{n=1}^{\infty} \frac{\pi(p_n^2)-n+2}{p_n^3-p_n}$ , ...

1
vote

0
answers

64
views

### Is there an upper bound on the number of partitions of a finite set of primes into 3 sets the products of 2 of which sum to the product of the third?

Is there an upper bound on the number of partitions of a finite set $S$
of prime numbers into 3 sets $A$, $B$ and $C$ for which the following holds?:
$$
\prod_{p \in A} p \ + \ \prod_{p \in B} p \ = ...

5
votes

2
answers

374
views

### When adding several $\sqrt[n]{p}$ to the rational numbers, what is the degree of field extension?

When adding several $\sqrt[n]{p}$ to the rational numbers, what is the degree of field extension?
For example, does $[\mathbb{Q}(\sqrt[n]{2},\sqrt[m]{3}):\mathbb{Q}]=mn$ hold true? Are there more ...

1
vote

1
answer

118
views

### Unramified composition for every extension

Let $K$ be a number field and $S$ be a finite set of primes. Is it possible to construct a finite extension $M$ of $K$ such that $LM/M$ is unramified at (the primes above) $S$ for all degree $n$ ...

4
votes

1
answer

408
views

### Smallest prime factor of numbers

The literature refers to smooth integers as \begin{equation}\Psi(x,y):=\#\{n\le x:P_1(n)\le y\},\end{equation} where $P_1(n)$ is the largest prime factor of $n$. There are lots of results studying $\...

3
votes

1
answer

552
views

### binomial coefficients are integers because numerator and denominator form pairs?

I've heard of a claim that when calculating the binomial formula with integer input:
$\mathrm{Bin}(n,k):=\prod^k_{i=1}\frac{n+1-i}{i}\in \mathbb{N}\ (\forall n,k\in\mathbb N)$
each denominator divides ...