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
15,955
questions
1
vote
0
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128
views
What is the possible reminders modulo 4 of an "odd part" of a polynomial?
Let $f(x)$ be a polynomial with integer coefficients. Let $f(x) = 2^k \cdot m$ where $m$ is odd. The questions are
What are the possible values of $m \mod 4$ (1, 3 or both)? I want the algorithm ...
- 935
3
votes
1
answer
673
views
Infinite dimensional lattice for integers and the Riemann hypothesis?
It is known that for each finite set of primes $p$ we have: $\log(p)$ are linear independent over the rational numbers.
We have $\log(ab) = \log(a)+\log(b)$ and $\log(n) = \sum_{p |n}v_p(n) \log(p)$.
...
- 2,462
4
votes
1
answer
179
views
For which quadratic number field, the algebraic integers are cusps for some Coxeter group?
Let $H^2=\{(x,y)\mid y>0\}$ be the hyperbolic upper-half plane.
Let $K=Q(\sqrt{d})$ be a quadratic number field, and $\mathcal{O}_K$ be the ring of algebraic integers in it.
Let $\Gamma=\Delta(p,q,...
- 545
1
vote
1
answer
188
views
Classification of L functions and Dirichlet series by poles
I am interested in the connection between particular Dirichlet series' abscissa of convergence and the poles of L-functions.
Let $D(z) = \sum_{n=1}^\infty\frac{a_n}{n^z}$ be a Dirichlet series ...
2
votes
0
answers
118
views
Imaginary quadratic fields with prime class number
Let $K$ be an imaginary quadratic field, with class number equal to an odd prime, say $h_K = p$.
In the proof Proposition 2.4 of this paper, Fukuda and Komatsu write,
"Since $h_K = p$, there ...
- 697
2
votes
2
answers
211
views
Conditional convergence of exponential sums related to a Hecke modular form
Definition
Consider the Fourier coefficients $\psi(n)$ of the modular form $\eta^4(6\tau)$,
which are defined in terms of $q=\exp(i2\pi\tau)$ by the identity:
$$\eta^4(6\tau) = q \prod_1^\infty (1-q^{...
2
votes
1
answer
368
views
The Fourier transform of the Liouville function?
The Liouville function in number theory is defined as:
$$\lambda(n) := (-1)^{\Omega(n)} \text{ where } \Omega(n) := \sum_{p|n} v_p(n)$$
Taking the discrete time Fourier transform and then taking the ...
- 2,462
2
votes
0
answers
225
views
Proof of Remark 6.14(b) of Milne's Arithmetic duality theorems'
Let $E/\mathbb{Q}$ be an elliptic curve.Let $\operatorname{Sha}(E/\Bbb{Q})$ be a Tate-Shafarevich group.
Milne's 'Arithmetic Duality Theorems' Remark 6.14(b) describe the following exact sequence.
...
- 1,405
4
votes
0
answers
89
views
Anisotropic semisimple groups with no real compact factor
Let $F$ be a number field, and let $G$ be a semi-simple connected, anisotropic algebraic group over $F$ which is $F$-simple (or almost simple, the question is agnostic to isogenies). Suppose further ...
- 2,814
2
votes
0
answers
111
views
What are the terms given by $\int_0^1\int_0^1 x^py^q \sin(\pi xy) (xy)^{xy} (1-xy)^{1-xy} \, dx \, dy$?
For a positive integer $n$ the terms given by
\begin{align}
& -\int_0^1 x^n \sin(\pi x) x^x (1-x)^{1-x} \, dx \\[8pt]
= {} & \int_0^1\int_0^1 (xy)^n \sin(\pi xy) (xy)^{xy} \frac{(1-xy)^{1-xy}}...
- 521
7
votes
0
answers
366
views
Subgroups of ${\rm GL}_{2}(\mathbb{Z}/2^{n} \mathbb{Z})$
Assume that $n \geq 3$. Is there a subgroup $H \leq {\rm GL}_{2}(\mathbb{Z}/2^{n} \mathbb{Z})$ whose order is a power of $2$ so that
$\bullet$ $\det : H \to (\mathbb{Z}/2^{n} \mathbb{Z})^{\times}$ is ...
- 20k
6
votes
2
answers
726
views
Prove positivity of a binomial sum
Some problems appear easy on the face of it, but perhaps they are not. Here is an instance of a certain calculation which is slightly reformulated from its original encounter in a current work. I have ...
- 41.8k
1
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0
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63
views
On a numbers $k$ with specific $2$-adic valuation
Let $a(n)$ be A002326 (i.e., multiplicative order of $2 \operatorname{mod} 2n+1$).
Let $b(n)$ be A179382 (i.e., the smallest period of pseudo-arithmetic progression with initial term $1$ and ...
- 3,474
3
votes
1
answer
157
views
Kernel of a map of Tate algebras
Let $A$ and $B$ be a pair of noetherian Tate algebras over $\mathbb{Q}_p$, and assume $\text{dim}_{\text{Krull}}(B) > \text{dim}_{\text{Krull}}(A)$. Is it true that any morphism $B \longrightarrow ...
- 1,651
2
votes
1
answer
168
views
Modified Gauss Sum when the characters have different period
Let $\chi$ be a Dirichlet character mod q, and
\begin{eqnarray}
t(\chi)=\sum_{n=1}^{q}\chi(n)e(\frac{n}{2q}).
\end{eqnarray}
Do we have a bound or formula for $t(\chi)$ similar to that of the usual ...
- 53
4
votes
0
answers
168
views
Bezout-type theorem for $p$-adic analytic plane curves
Let $p$ be a prime, and let $f,g \in \mathbb{Z}_p[[x,y]]$ be power series convergent on all of $\mathbb{Z}_p$. Suppose that the intersection of the analytic plane curves cut out by $f$ and $g$ is ...
3
votes
1
answer
188
views
Generators of the ideal class group
Theorem 4 of Eric Bach's "Explicit bounds for primality testing and related problems" states the following:
Let $K$ be a number field of degree greater than 1. Let $d$ be the absolute value ...
- 33
6
votes
2
answers
453
views
Difficult elliptic curves for $a^4+b^4+c^4+d^4 = (a+b+c+d)^4$?
Similar to the case $x^4+y^4+z^4 = 1$ discussed in this MO post, define the system,
$$x^4+y^4+z^4+1 = (x+y+z+1)^4\tag1$$
$$\frac{x^2+x+1}{(x+y+1)(x+z+1)}=u\tag2$$
$$\frac{y^2+y+1}{(y+z+1)(y+x+1)}=v\...
- 12.1k
0
votes
0
answers
94
views
Formula for individual term of the Proth numbers
Let $a(n)$ be A080075 i.e. Proth numbers: of the form $k2^m + 1$ for $k$ odd, $m \geqslant 1$ and $2^m > k$.
The sequence begins with
$$
3, 5, 9, 13, 17, 25, 33, 41, 49, 57, 65, 81, 97, 113, 129
$$...
- 3,474
12
votes
1
answer
611
views
On the equation $9x^3+y^3=z^2+3$
The question is whether there exist integers $x,y,z$ such that
$$
9x^3+y^3=z^2+3.
$$
This is one of the nicest (if not the nicest one!) cubic equations for which I do not know whether integer ...
- 5,957
0
votes
1
answer
148
views
Coefficients of 0,1-polynomials factorization
Let $n\in\mathbb{N}$ and $P_{n}$ is $0,1$-polynomial whose coefficients are binary digits of $n$.
Let $Q_{1}(x) \cdot Q_{2}(x) \cdots Q_{m}(x)$ - polynomial factorization (over integers) of $P_{n}$.
...
- 462
0
votes
1
answer
151
views
“Smallest” non-zero linear combination of vectors to obtain a non-negative vector
We say that a vector $\mathbf{x}$ in $\mathbb{Z}^j$ is non-negative if it is of the form
\begin{bmatrix}
x_1 \\
x_2 \\
\vdots \\
x_j \\
\end{bmatrix}
where $x_{j} \geq 0$.
Suppose that ...
- 225
2
votes
1
answer
281
views
Sets of integers "a little less dense" than the set of prime numbers
Given a set $A \subseteq \mathbb{N}$ of positive integers, put
$$
S_A: \mathbb{N} \rightarrow \mathbb{R}, \ \ \ \
N \mapsto \sum_{n \in A \cap \{1, \dots, N\}} \frac{1}{n}.
$$
There are obvious ...
- 19.5k
2
votes
0
answers
69
views
Possible subsequence of the A110978
Let $a(n)$ be A110978 i.e. odd integers that are nonprime, such that there exist two factors of each number that when multiplied together in binary base, do not ever require the use of a "carry&...
- 3,474
2
votes
0
answers
197
views
Squares whose differences are squares
EDIT. I've just noticed a thread from 2011 in the "Related" column on the right (click me), where a closely related question is being discussed (the main difference seems to be that, in ...
- 9,636
4
votes
2
answers
319
views
Number of Salem–Spencer subsets of $\{1,2,3,\dots ,n\}$
I was wondering about sets that do not contain any $3$-term AP, and came to know that the official name of such a set is Salem–Spencer set. I was considering the question of counting the number of ...
- 781
5
votes
0
answers
175
views
Empirical bounds on $\left|\frac{\zeta'(1+it)}{\zeta(1+it)}\right|$
It is reasonable to expect that $$\left|\frac{\zeta'(1+it)}{\zeta(1+it)}\right| < 2 \log \log t$$
for all $t\geq 4$ (say): a somewhat stronger bound is known for $t\geq 10^{165}$ or so (Theorem 5 ...
- 19.4k
0
votes
0
answers
43
views
How to find A(i, d)?
Let $s(n)$ denote the digit sum of a natural number $n$. For $i, d\in \mathbb{N}$ define $$A(i, d) = \limsup_{m\to \infty}\frac{|\{n\leq m | s(n)\equiv i\mod d\}|}{m}.$$ Compute $A(i, d)$ for all $i, ...
- 11
1
vote
1
answer
156
views
Density of a set of numbers whose prime factors are defined by congruences
Let $S$ be the set of positive integers not divisible by $3$ where if $p$ is a prime factor of $n \in S$ and $p \equiv 1\bmod 3$ then $p^2$ does not divide $n$, but if $p\equiv2 \bmod 3$ then $p^2$ ...
3
votes
0
answers
239
views
On thickness of binary polynomials
OEIS A169945 introduces the concept of thickness of a polynomial as the magnitude of the largest coefficient in the expansion of the square of the polynomial. Considering the $2^{n+1}$ polynomials $p(...
- 781
2
votes
0
answers
131
views
Prime splitting in the division field of an elliptic curve
Let $E/\mathbb{Q}$ be an elliptic curve with good reduction at two distinct primes $p, \ell$. Suppose the mod $\ell$ Galois representation associated to $E$ is surjective. Let $K=\mathbb{Q}(E[\ell])$ ...
- 1,412
26
votes
1
answer
995
views
Is every polynomial of the form $2x^{2n} -x^n +1$ irreducible over $\mathbb{Z}$?
Is every polynomial of the form $2x^{2n} - x^n +1$ irreducible for $n>0$?
Motivation: A few years ago a student asked if $29$ was the largest number which is prime and one more than a perfect ...
- 6,100
4
votes
4
answers
427
views
A cubic equation, and integers of the form $a^2+192b^2$
This question resembles my previous question A cubic equation, and integers of the form $a^2+32b^2$ , but seems to be more difficult.
We are trying to determine whether there are any integers $x,y,z$ ...
- 5,957
1
vote
1
answer
109
views
If $p^k m^2$ is an odd perfect number with special prime $p$, then must $m^2 - p^k = s^2 - t^2$ hold for some $s$ and $t$?
My present question is as is in the title:
If $p^k m^2$ is an odd perfect number with special prime $p$, then must $m^2 - p^k = s^2 - t^2$ hold for some $s$ and $t$?
It is known that $m^2 - p^k$ is ...
- 1,008
1
vote
1
answer
134
views
Iwahori action on the $p$-ordinary line of a principal series representation
$\DeclareMathOperator\GL{GL}\DeclareMathOperator\diag{diag}\DeclareMathOperator\Ind{Ind}\newcommand\Iw{\mathrm{Iw}}\DeclareMathOperator\ord{ord}$Let $F$ be a $p$-adic local field, i.e. a finite ...
- 579
0
votes
0
answers
59
views
Upper bound for an additional Product formula
We have three sequences of positive integers $l$, $p$ and $q$ such that:
$$
p_1 \geq p_2 \geq \cdots \geq p_k\text{ and } q_1 \geq q_2 \geq \cdots \geq q_k \geq \cdots \geq q_h \text{ where: } k < ...
3
votes
0
answers
216
views
Number of zeros of the zeta function along horizontal lines
Are there any known results about the number of zeros of the zeta function along horizontal lines of the complex plane? The Riemann hypothesis states that for any such line the number is at most 1, ...
- 31
3
votes
1
answer
161
views
Approximating $p$-adic power series by polynomials
Let $p$ be a prime, and let $f \in \mathbb{Z}_p[[x_1,\dots,x_d]]$ be a power series convergent on all of $\mathbb{Z}_p^d$. We make the following definition concerning the approximation of $f$ by ...
4
votes
2
answers
436
views
Reference request - Pillai-Selberg Theorem
I want to find a proof of the following claim. Let $\Omega(n)$ denote the number of prime factors of an integer $n$ counted with multiplicity. Then $\Omega(n)$ equidistributes over residue classes. ...
- 251
2
votes
0
answers
96
views
Extensions of $F$-isocrystals
Let $X$ be a smooth affine scheme over $k$, a finite field. Let $W(k)$ denote the Witt ring, and $K$ its fraction field. Fix a smooth lift of $X$ to $K$ and denote it by $X_K$.
Let $b\in X(k)$ denote ...
- 1,651
2
votes
1
answer
134
views
Existence of an integer coefficients polynomial with prescribed bounds on [0,4]
Is there a polynomial f with integer coefficients that satisfies the following criteria:
f is not constant;
for all $x\in[0,1]$, $1-\frac{1}{x}\leq f(x)\leq \frac{1}{x}$;
For all $x\in [1,4]$, $0\leq ...
- 237
2
votes
1
answer
370
views
Limit of an infinite series with quadratic arguments
I have encountered a limiting process on some infinite series. So, I would like to ask:
QUESTION. Assume $n$ is an even positive integer. Is this true?
$$\lim_{r\rightarrow1^{-}}\sum_{j=1}^{\infty}\...
- 41.8k
17
votes
2
answers
845
views
Understanding absolute Galois group from its representations
Background. A major theme of modern number theory is to study the absolute Galois group $\text{Gal}(\overline{\mathbb Q} / \mathbb Q)$. Galois representation theory attempts to understand $\text{Gal}(\...
- 821
3
votes
1
answer
203
views
Partition numbers and Gaussian binomial coefficient
Let $a(n)$ be A000041 i.e. the number of partitions of $n$ (the partition numbers).
Let $T(n, k)$ be A083906. Here
$$
T(n, k) = [q^k]\sum\limits_{m=0}^{n} \binom{n}{m}_q
$$
where $\binom{n}{m}_q$ ...
- 3,474
3
votes
1
answer
303
views
Rationals polynomials with integers values
I have asked this question here (*), but there are no answer.
Let $q \in \mathbb N \cap [2,+\infty[$ and $P \in \mathbb Q[x]$ with $\forall k \in [0,\deg(P)] \cap \mathbb N, P(q^k) \in \mathbb Z$.
Is ...
- 3,801
1
vote
1
answer
199
views
How to compute the asymptotic constant for the count of $S_3$-sextic number fields?
I am currently reading this paper counting $S_3$-sextic fields
Manjul Bhargava and Melanie Matchett Wood, The density of discriminants of $S_3$-sextic number fields, Proc. Amer. Math. Soc. 136 (2008),...
6
votes
3
answers
882
views
A polynomial identity for $\displaystyle \sum_{k=0} ^m (-1)^ka^{m-k}b^k$
I asked this question on MSE here.
I was solving this problem:
Show that if $\gcd(a, b) = 1$ and $p$ is an odd prime, then $\displaystyle \gcd\left(a+b, \frac{a^p+b^p}{a+b}\right)=1$ or $p$.
This ...
- 227
7
votes
1
answer
300
views
Rational prime factors in the components of powers of Gaussian primes
Let $\pi=a+bi\in \mathbb{Z}[i]$ be a Gaussian prime with $a$ and $b$ nonzero, and $b$ even. For odd rational primes $p=\pi\bar\pi$ and $q\neq p$, define $\pi^{\frac{1}{2}\left(q-\left(\frac{-1}{q}\...
4
votes
0
answers
128
views
Vanishing exponential sums of fractional parts of polynomials
Let $p$ be an integer polynomial and $k$ be a natural number, both fixed. Is it the case that if
$$C(\alpha) = \sum_{i=1}^k e(\alpha \{p(i)/k\})$$
equals 0, then $\alpha$ is an integer? Here, $e(x) = ...
- 41
7
votes
1
answer
389
views
A parametric elliptic curve for $x^4+y^4+z^4 = 1$?
Noam Elkies found that $x^4+y^4+z^4 = 1$ has infinitely many rational points $xyz \neq 0$ using an elliptic curve. We use a different approach that will produce pairs of solutions and a parametric ...
- 12.1k