**1**

vote

**0**answers

15 views

### degeneration of reductive group

If $A$ is a mixed characteristic complete DVR (I'm only actually interested in $\mathbf{Z}_p$) and $G/A$ is a group scheme whose generic fibre is connected reductive and split, is the special fibre ...

**1**

vote

**1**answer

115 views

### Are there infinitely many $k$ for which $\sigma(k)/k $ is a square?

I would like to know if there are infinitely many $k$ for which
$$\sigma(k)/k=n^2$$ such that: $m=kn$ with $m,n>0 $ ?
Note: $\sigma(\frac{m}{ n})$ is the sum of divisors function of ...

**1**

vote

**0**answers

56 views

### binomial coefficients and irrationals

The following, probably either currently impossible to deal with, or
having a negative solution, arose from an ergodic theory question,
presumably itself currently intractible. I am not a number ...

**1**

vote

**0**answers

87 views

### Probability of correlated residues

Given $N,c\in\Bbb N$, where $c\ll(\log N)^{1/b}$ for any $b>1$ is fixed, what is the probability that given $A_1,A_2,A_3\in\Bbb N$ with ...

**1**

vote

**1**answer

216 views

### Weierstrass form of genus one $y^{10} z^{30} - 8000 y^{4} z^{20} + 12800000 z^{20} + 1600 y^{2} z^{10} - 64=0$

Related to the n-conjecture.
We are looking for Weierstrass form and map from it of the genus one curve:
$$ y^{10} z^{30} - 8000 y^{4} z^{20} + 12800000 z^{20} + 1600 y^{2} z^{10} - 64=0 $$
It is ...

**2**

votes

**1**answer

181 views

### Counting function for prime pair with bounded gaps between them [duplicate]

I'll start by noting that I am not at all an expert on number theory. However I do use it in a proof and would like your assistance if possible.
Yitang Zhang breakthrough result established that ...

**2**

votes

**0**answers

146 views

### Is the twisted symmetric fifth power $L$-function holomorphic?

Let $\pi$ be a Maass cusp form for SL($2,\mathbb Z$). Let $\omega$ be a primitive Dirichlet character.
Let us consider the $L-$ function
$$L(s,Sym^5 \pi \times \omega)$$ or $L(s,Sym^6 \pi \times ...

**6**

votes

**1**answer

359 views

### Pure motives and compatible systems of $\ell$-adic representations

I am trying to understand the statement of the conjectures of Deligne on special values of certain $L$-functions, from his article titled, "Valuers de Fonctions L et periodes d'integrales" which ...

**0**

votes

**0**answers

71 views

### Finite-index subgroups of the ideles

Let $k$ be a number field and denote by $J_k$ the idele group of $k$. Recall that the finite-index open subgroups of $J_k$ which contain $k^*$ are very important in class field theory. My question ...

**13**

votes

**1**answer

502 views

### Elementary Proof of Infinitely many primes $\mathfrak{p} \in \mathbb{Z}[i]$ in the sector $\theta < \arg \mathfrak{p} <\phi $

A quick look at the primes in $\mathbb{Z}[i]$ suggests they might be evenly distributed by angle if we zoom out on a coarse enough scale.
I would like ask about the much weaker statement forgetting ...

**-1**

votes

**0**answers

159 views

### Straight line complexity of $k!a$ where $(a,p)=1$

In Qi Cheng's paper, an algorithm is provided to calculate $k!a$ at some random $a∈ℕ$ ($a$ is not input to algorithm, only $k$ is), what is the probability that given a prime $p$ such that ...

**11**

votes

**1**answer

277 views

### Automorphisms of finite order in $Out(\widehat{F_2})$

Let $\widehat{F_2}$ be the pro-$\ell$ completion of the free group of rank 2, where $\ell$ is some prime.
Every outer automorphism of $F_2$ induces an outer automorphism of $\widehat{F_2}$, hence an ...

**5**

votes

**0**answers

159 views

### Examples of Rankin-Selberg L-functions from Eisenstein series

I've been digging for awhile to not much success, so I figure I would try here:
I am looking for some references which compute explicitly examples of Rankin-Selberg L-functions from the constant ...

**-2**

votes

**0**answers

108 views

### question on collatz trajectories/pattern in form $2^n - 1$ [closed]

I recently noticed this remarkable general "wedge" pattern in base 2 for Collatz iterates starting with values $2^n - 1$, displayed here for $n=20$.
Has this been noticed or analyzed before?
...

**-3**

votes

**0**answers

77 views

### How can I solve a diophantine equation with 3 variables? [closed]

My equation looks like:
$$
x + 17y + 289z = 3367
$$
where
$$
20 < x, y, z <100
$$
Is it possible to come up with a list of possible solutions? I do not know where to begin. I know I can't use ...

**1**

vote

**1**answer

296 views

### Analytic Number Theory without Pigeonhole Principle [closed]

I don't know if this is an appropriate question for this website, but I will try my luck.
I am an undergraduate student, and recently I became interested in analytic number theory. When I started ...

**7**

votes

**1**answer

348 views

### What is the normal closure of $GL_2(\mathbb{Z})$ inside $GL_2(\mathbb{Z}_\ell)$?

This weird problem popped up in my research:
Let $\ell$ be a prime. Is there a description of the smallest normal subgroup of $GL_2(\mathbb{Z}_\ell)$ containing $GL_2(\mathbb{Z})$?
Is there a ...

**7**

votes

**0**answers

231 views

### Residue class sufficiency sets for the Collatz conjecture

I have recently managed to show a sequence of sufficiency sets for the Collatz conjecture whose natural density approaches 0 (the set theoretic limit approaches the set $\{1\}$). It is an extension of ...

**5**

votes

**1**answer

198 views

### Is $\liminf \frac{\sigma_{k}(n)}{n}$ finite for every $k$?

Can someone show me how to prove that $$\liminf_{n \to \infty} \frac{\sigma_{k}(n)}{n} < \infty$$ for every natural number $k$? Or is this problem open?
Here, ...

**6**

votes

**0**answers

317 views

### “Forthcoming paper” of Goldston-Graham-Pintz-Yıldırım

The above-named authors of [1] and its (significantly different) published version [2] write:
In a forthcoming paper, we will show how the methods here can be extended to prove corresponding ...

**2**

votes

**3**answers

324 views

### Integral points on a particular family of curves

This is a follow-up to this question (and comments thereon). Namely, it follows from Felipe Voloch's comment that for any $n>2$ there is a finite set of integral $(x, y),$ such that
$$
...

**3**

votes

**1**answer

125 views

### Given n and q, how to find p so q$\neq$n-th power (mod p)?

Reasonable exceptions allowed on $q$. Example solution: $n=2$.
Suppose $q$ is odd. Let $p$ be so $pq\equiv -1$ (mod 8). Then $q\neq$ 2nd power (mod $p$) is the same as ...

**10**

votes

**1**answer

394 views

### When is the image of an integral polynomial contained in the image of another?

Suppose $f$ and $g$ are polynomials with integral coefficients and $f(\mathbb Z)\subset g(\mathbb Z)$. Is there any relation between $f$ and $g$?
For instance, this happens if $f=g\circ h$ for some ...

**0**

votes

**2**answers

211 views

### Intersection of two lattices

Suppose that $\Lambda_1, \Lambda_2$ are two sub-lattices of $\mathbb{Z}^n$ of full rank, defined by congruence modulo a prime $p$. That is, there exist two vectors with integer entries $\mathbf{a}, ...

**-2**

votes

**0**answers

137 views

### What would both Goldbach's conjecture and GRH tell us about the distribution of k-central numbers?

Assume Goldbach's conjecture. Then for all integer $n$ greater than 1, there exists a non negative integer $r$ such that both $n+r$ and $n-r$ are prime. I call such an $r$ a primality radius of $n$, ...

**7**

votes

**2**answers

281 views

### Field of definition of dominant morphisms

Let $k$ be an algebraically closed field and $k_0$ a sub-field. Let $X,Y$ be two projective varieties defined over $k_0$. Suppose that that there exists a dominant morphism $f$ between $X_k=X\otimes ...

**2**

votes

**0**answers

84 views

### Distribution of residue classes of totients of (univariate) polynomials

Let $\phi$ denote Euler's totient function and $f$ a non-constant univariate polynomial with integer coefficients such that $f(u) \in \mathbf N^+$ for all $u \in \mathbf N^+$ (assume $f$ is ...

**4**

votes

**1**answer

164 views

### Equidistribution of representations by a binary cubic form

Let $f(x,y)\in\mathbb{Z}[x,y]$ be a binary cubic form with nonzero discriminant, and for a positive integer $m$ consider the integral representations $f(x,y)=m$. Assume that the number of ...

**12**

votes

**2**answers

402 views

### Number of nonzero terms in polynomial expansion (lower bounds)

Let $f(x) = a_1x^{z_1} + a_2x^{z_2} + \cdots + a_kx^{z_k}$ be a polynomial with coefficients $(a_1, \ldots, a_k) \in \mathbb{F}_q^*$ and $z_i$ are distinct positive integers. If I need to compute the ...

**9**

votes

**2**answers

421 views

### Intuition behind Kronecker's congruence?

The modular polynomial is defined by$$\Phi_n(X, \tau) = \prod_{\tau} (X - j(\tau)),$$where $j$ is the elliptic modular function and $\tau$ is running through classes of imaginary quadratic integers of ...

**14**

votes

**1**answer

278 views

### Why there are only finitely many $\overline{\mathbb{Q}}$-isomorphism classes of elliptic curves with CM by $\mathcal{O}$?

For someone who does not have a very extensive knowledge of number theory, what is a good intuitive explanation as to why there are only finitely many $\overline{\mathbb{Q}}$ isomorphism classes of ...

**0**

votes

**0**answers

92 views

### A question on integers relatively prime to their Euler totien function

For the problem I am working on I have realised that some of the proofs could be slightly simplified if a certain number theoretic question has a positive solution. Now, the problem is in finite group ...

**0**

votes

**1**answer

87 views

### Computation of Hilbert symbol of order 4

We have explicit expressions for the quadratic Hilbert symbol over $\mathbb Q$, for example $\left(\dfrac{x,y}2\right)_2=(-1)^{\frac{x-1}2\frac{y-1}2} (x,y\ne2)$. Are similar expressions known for ...

**13**

votes

**0**answers

233 views

### Result of Deuring, intuitive way to see it's true/quickest way to prove?

There is the following result of Deuring that goes as follows:
Let $E/L$ be an elliptic curve defined over a number field $L$ with complex multiplication by an order $\mathcal{O}$ in an imaginary ...

**8**

votes

**2**answers

845 views

+50

### Is there a fixed integer $x>1$ satisfing ${\sigma}^{k}(x)\equiv 0\pmod{x}$ for all positive integers $k$?

This question related to this question from SE. I'm interested to know if there exists an integer $x>1$ that satisfies $${\sigma}^{k}(x)\equiv 0\pmod{x}$$
for all positive integers $k$.
Note. ...

**4**

votes

**0**answers

182 views

### Unirationality over $\mathbb{Q}$

It is known that all smooth projective quartic hypersurfaces of suitably large dimension are unirational over $\overline{\mathbb{Q}}$. Are there any results regarding unirationality over $\mathbb{Q}$ ...

**5**

votes

**1**answer

262 views

### Representations of the unit group in a ring of integers

Let $K/\mathbb{Q}$ be a finite extension of degree $d > 1$. Suppose that $\omega_1, \cdots, \omega_d$ is a basis for $K$ over $\mathbb{Q}$. Further, we assume that $\omega_1, \cdots, \omega_d \in ...

**0**

votes

**0**answers

42 views

### Does such a morphism necessarily coincide with the degree?

Let $\mathcal{M}$ be the set of elements the Selberg class identical up to a twist (that is, we consider that $F\in\mathcal{M}$ and $F_{\theta}:s\mapsto F(s+i\theta)$ with $\theta\in\mathbb{R}$ are ...

**10**

votes

**2**answers

572 views

### Upper density of the set of $n$'s such that $p(n)$ is prime, where $p$ is polynomial

The starting point for this question is the following (false) statement
$\forall n\in \mathbb{N} (n^2 + n + 41 \text{ is prime}).$
Given a polynomial function $p:\mathbb{N} \to ...

**1**

vote

**0**answers

70 views

### Bounded discrepancy multiplicative functions

A rather specific question, concerning the second remark of Tao in
...

**3**

votes

**1**answer

131 views

### Fourier Transform of Eisenstein Series - Sum of Divisors or Ramanujan Sums?

I am stuck on this computation of the Fourier coefficients of Eisenstein series. For $\Gamma = SL(2, \mathbb{Z})$ and $\Gamma_\infty = \left\{ \left( \begin{array}{cc} 1 & m \\ 0 & 1 ...

**10**

votes

**0**answers

205 views

### Must the sum of the digits of $n^k$ decrease infinitely often, for $n,k\in\mathbb{N}$ and $n$ not a power of $10$?

This is a (rephrased) repost of a question I asked on MSE about 6 months ago, but didn't receive a definitive answer.
Let $S(n)$ be the sum of the digits of $n$ (in base $10$), is it true that for ...

**0**

votes

**0**answers

55 views

### Finite Ramanujan expansions over a finite field

I'm wondering if we could have an analogy in finite fields. After all, the Discrete Fourier Transform (DFT) has been generalized to finite fields as well (with essentially identical properties as in ...

**12**

votes

**2**answers

449 views

### Infinitely many irreducible polynomials of the form f(X^2) + X mod 3?

Are there infinitely many polynomials $f \in \mathbb{F}_3[X]$ for which $f(X^2) + X$ is irreducible?

**5**

votes

**0**answers

185 views

### Genus of $k(T)$ is $0$ without using Riemann-Roch

Let $F$ be a function field with one variable with total constant field $k$, and let $X$ be the set of all places of $F$. How do I show that the genus of $k(T)$ is $0$ without using Riemann-Roch? Is ...

**2**

votes

**1**answer

219 views

### Best known zero-free region for Dirichlet $L$-functions in the $q$-aspect

It is classical that there is a $c > 0$ such that for all Dirichlet characters $\chi$ except for at most one exception, one has that $L(s,\chi)$ has no zeroes for $\sigma > 1 - \frac{c}{\log{q} ...

**0**

votes

**0**answers

99 views

### Is there a rather natural space an automorphism of which is the Mellin transform?

Disclaimer: this question might be a little too vague and thus not suitable for this site despite the soft-question tag. If so, feel free to migrate it to MSE.
I just read this and, trying to find ...

**6**

votes

**1**answer

260 views

### Can one define “Ramanujan Summation” over algebraic number fields?

With some trepidation, I ask to "evaluate" badly divergent sums. Generalizing $\sum n = -\tfrac{1}{12}$ what would be the value of this sum over $\mathbb{Z}[i]$?
$$\sum_{m,n \geq 0} (m+in) ...

**0**

votes

**0**answers

97 views

### A (weak?) lower bound on primes in arithmetic progressions in short intervals

I was wondering if the following could be established by the methods that go into e.g. Linnik:
$\textbf{Claim. } \text{Let $\chi$ be a nonprincipal quadratic character of conductor $q$, and (e.g.) $c ...

**1**

vote

**1**answer

95 views

### On the upper Banach density of the set of positive integers whose base-$b$ representation misses at least one prescribed digit

Let $b$ be a fixed integer $\ge 2$ and $A$ a proper subset of $\{0, \ldots, b-1\}$. Then define $X$ to be the set of all positive integers whose base-$b$ representation consists only of digits from ...