Questions on more advanced topics of number theory, such as quadratic residues, primitive roots, prime numbers, non-linear Diophantine equations, etc. Consider first if (elementary-number-theory) might be a more appropriate tag before adding this tag.

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Definition of $p$-Hilbert class field

What is the definition of $p$-Hilbert class field of a number field $K$ for a prime $p$ ?
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1answer
48 views

Proof that $\sqrt{3} \notin \mathbb{Q}(\theta)$ where $\theta^4-2=0$. [on hold]

This is a problem in Robert Ash's lecture notes in Algebraic Number Theory. I have to prove that $\sqrt{3} \notin K=\mathbb{Q}(\theta)$ where $\theta^4-2=0$, using the fact that ...
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2answers
42 views

Prove that to any three numbers positive integers [on hold]

Prove that for any three positive integers, following equality holds $$\operatorname{lcm}(ab , bc , ca ) \cdot \gcd(a , b, c )=abc$$
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0answers
25 views

Does $\zeta(s)^2 \pm \zeta(1-s)^2$ have roots at the $\rho$s?

Maybe a strange (or stupid) question, but does: $$\zeta(s)^2 \pm \zeta(1-s)^2$$ also have roots equal to the non-trivial zeros ($\rho$) ? At first sight you would expect so, however when I tried to ...
2
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3answers
55 views

Is it necessary and sufficient that $6$ divides $n^2$ for the positive integer $n$ to be divisible by $6$? [on hold]

As the title suggests, is it a necessary and sufficient that $6$ divides $n^2$ for the positive integer $n$ to be divisible by $6$? Like, I understand the dictionary definitions of necessary and ...
3
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1answer
78 views

Prove that the number $2^{2^n} + 2^{2^{n - 1}} + 1$ can be expressed as the product of at least $n$ prime factors, not necessarily distinct.

Prove that the number $$2^{2^n} + 2^{2^{n - 1}} + 1$$ can be expressed as the product of at least $n$ prime factors, not necessarily distinct. I have tried out a few smaller numbers of $n$, and I ...
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2answers
55 views

what is the definition of numbers? [duplicate]

Well the question may seem obvious but I can't really find a proper answer to this. Mathematics all seem kind of difficult to understand so please help. I believe it is a quantity. Thanks in advance.i ...
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35 views

Is the field of real algebraic numbers a complete field?

Let $\mathbb{R}_{alg}$ be the field of real algebraic numbers. Is there exist a metric $|\cdot|$ for which $(\mathbb{R}_{alg}, |\cdot|)$ is a complete field (i.e. any Cauchy sequence converges in ...
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0answers
19 views

sextic reciprocity and divisibility question

Regarding the question if $p|(2^{2(p-1)/6}+2^{(p-1)/6}+1) $ where $p$ is a prime of the form $7\mod 8 $ That is how far I got: $2^{(p-1)/6} \mod\ p\equiv x $ if the solution of $x^6\ mod\ ...
5
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1answer
75 views

Counting square free numbers co-prime to $m$

Counting square free numbers $\le N$ is a classical problem which can be solved using inclusion-exclusion problem or using Möbius function (http://oeis.org/A071172). I want to count square free ...
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1answer
37 views

Proving Bezout's Theorem

I need to prove Bezout's Theorem and the recommended method is using the induction on the number of steps before the Euclidean algorithm terminates for a given input pair.$~~~~~~$ I am having hard ...
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1answer
31 views

Expected value of discrete functions. [on hold]

I am doing some research in number theory(High school-so nothing advanced). During this I came across this post. I have not done much statistics. So could someone explain to me why if $\displaystyle ...
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0answers
55 views

Showing that $U_n$ and $U_m$ must have primes between them

Given that $$U_n=\underbrace{1\cdots1}_{n\text{ times}}$$ and $n >2$, how can one show that if $m$ and $n$ have primes between them, then $U_n$ and $U_m$ must also have primes between them? ...
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0answers
14 views

Judge whether a function is $\mathcal{EF}$ or $\mathcal{PRF}$

All of the functions discussed below are total number-theoretic functions. Define two functions: $$ f:\mathbb{N}\to\mathbb{N},f(n)=\lfloor n\cdot e \rfloor \\ g:\mathbb{N}\to\mathbb{N},g(n)=\lfloor ...
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0answers
31 views

Pythagorean triangle with in-radius r: problems

If there is no odd prime divisor of $r$, prove that there is only one Pythagorean triangle with in-radius r. If $r=pq$, the product of two distinct primes, prove that there are four ...
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3answers
28 views

Problems on Pythagorean triangle

Show that there is one (no) Pythagorean triangle whose sides are in arithmetic (geometric) progression. The problem has two parts. There is one Pythagorean triangle whose sides are in arithmetic ...
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2answers
37 views

Show that $a^{16}-b^{16}$ is divisible by $133$ if $a$ and $b$ are both prime to $85$

Show that $a^{16}-b^{16}$ is divisible by $133$ if $a$ and $b$ are both prime to $85$ Since $(85, a)=1(17,5)$ and $(85, b)=(17,5)$ then $a^{16}-1\equiv (mod ~17)$, $a^{4}-1\equiv (mod~ 5)\implies ...
3
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2answers
39 views

Find the last two digits of $33^{100}$

Find the last two digits of $33^{100}$ By Euler's theorem, since $\gcd(33, 100)=1$, then $33^{\phi(100)}\equiv 1 \pmod{100}$. But $\phi(100)=\phi(5^2\times2^2)=40.$ So $33^{40}\equiv 1 ...
3
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4answers
48 views

Find remainder when $777^{777}$ is divided by $16$

Find remainder when $777^{777}$ is divided by $16$. $777=48\times 16+9$. Then $777\equiv 9 \pmod{16}$. Also by Fermat's theorem, $777^{16-1}\equiv 1 \pmod{16}$ i.e $777^{15}\equiv 1 \pmod{16}$. ...
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1answer
15 views

simplification and number system [on hold]

The sum of all digits except the unity that can be substituted at the place of k in order to be divisible by 8 in the number 23487k2 is?
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0answers
31 views

find a method for twin primes and with Golbach conjecture [on hold]

There are infinitely many twin primes. Two primes (p, q) are called twin primes if their difference is 2. Let be the number of primes p such that p<= x and p + 2 is also a prime. a sample ...
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1answer
33 views

Find the missing digit in the number 23104*791

Find the missing digit in the number $23104*791$ if (i) it is divisible by $11$, (ii) it is divisible by $13$, (iii) it is divisible by $63$. (i) $23104*791=231 ...
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0answers
9 views

Where $a, b$ coprime, does $ax + b$ generate infinitely many 2-almost primes, infinitely many 3-almost primes, etc.?

I've seen various references to Dirichlet's theorem on arithmetic progressions claiming that where $a, b$ coprime, $ax + b$ not only generates infinitely many primes, but also infinitely many ...
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1answer
19 views

Show that $x_1x_2\cdots x_n (mod~ m)\equiv (x_1 (mod~m)\cdot x_2 (mod~m)\cdots x_n (mod~m))(mod~ m)$

Show that $x_1x_2\cdots x_n (mod~ m)\equiv (x_1 (mod~m)\cdot x_2 (mod~m)\cdots x_n (mod~m))(mod~ m)$ I know that $a\equiv b (mod ~ m)$, $c\equiv d (mod ~m)$ implies $ac\equiv bd (mod ~m)$ but how ...
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2answers
39 views

In how many ways I can write a number $n$ as sum of $4$ numbers?

The precise problem is in how many ways I can write a number $n$ as sum of $4$ numbers say $a,b,c,d$ where $a \leq b \leq c \leq d$. I know about Jacobi's $4$ square problem which is number of ways ...
4
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2answers
50 views

Use Wilson theorem to show that $63! + 1 \equiv 0 \mod ~ 71$

Use Wilson theorem to show that $63! + 1 \equiv 0 \mod ~ 71$. 71 is prime then Wilson theorem says that $(71-1)!+1=0 \mod ~ 71$ i.e $70!+1\equiv 0 \mod ~ 71$ then how to proceed further?
3
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7answers
77 views

What is the remainder when $6\times7^{32} + 7\times9^{45}$ is divided by $4$?

What is the remainder when $6\times7^{32} + 7\times9^{45}$ is divided by $4$ ? $7 \equiv 3 \pmod 4$ $7^2 \equiv 9 \pmod 4\equiv 1 \pmod 4$ $(7^2)^{16} \equiv 1^{16} \pmod 4$ i.e $7^{32} ...
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1answer
33 views

Find out a process to generate pairs of distinct positive integer $m$, $n$ with $\phi(m) = \phi(n)$.

Find out a process to generate pairs of distinct positive integer $m$, $n$ with $\phi(m) = \phi(n)$. Attempt: The pairs $m=1, ~ n=2$; $m=3, ~n=4$ satisfy the problem. But I need a ...
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0answers
30 views
+50

Understanding an example of a prime-like non-finite additive basis

In this answer on MO, the user Gene S. Kopp gives an example of a relatively "big" set $A\subset \mathbb{N}$ with relatively "small" gaps that fails to be an asymptotic finite basis. I'm having a ...
3
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0answers
22 views

counting function of system of equations and Circle method

I came up with the follwing question while looking on Davenport's book: Analytical Methods for Diophantine equations and Inequalities. When introducing the Circle method gives an example on how to ...
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6answers
396 views

Elementary number theory - prerequisites

Since summer comes with a lot of spare time, I've decided to select a mathematical subject I want to learn as much as possible about over the next three months. That being said, number theory really ...
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4answers
103 views

Given primitive solution to $\frac{1}{a}+\frac{1}{b}=\frac{1}{c}$, show $a+b$ is a perfect square [duplicate]

If $a,b,c$ are positive integers and $\gcd(a,b,c)$ is $1$. Given that $\frac{1}{a} + \frac{1}{b} = \frac{1}{c}$ then prove that $a+b$ is a perfect square. I was trying to get something useful from ...
2
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1answer
40 views

Why is $x^{100} = 1 \mod 1000$ if $x < 1000$ and $\gcd (x,1000) = 1$?

Let $U(1000) =$ the multiplicative group of all integers less than and relative prime to $1000$. "Show that for every $x \in U(1000)$ it is true that $x^{100} = 1 \mod 1000$." Been thinking ...
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0answers
24 views

Proving that there exist products of $a_k \equiv 1 \pmod {a_i}$ [on hold]

Let $n>2$ be an integer. Prove that there exist numbers $a_1, a_2, \ldots ,a_n$ such that $$a_1a_2\cdots \widehat{a_i}\cdots a_n \equiv 1 \pmod{a_i}$$ for $i=1,2,3,\ldots,n$. Here ...
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3answers
57 views

Find solutions to $4x^2\equiv 1\pmod {29}$ [on hold]

Find the solutions to the congruence: $$4x^2\equiv 1\pmod {29},\rm{ie},(2x)^2\equiv 1\pmod{29}$$
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1answer
34 views

Non real complex in metric completions of $\mathbb Q$

Process of completion of $\mathbb Q$ using the absolute value $|x|$ does not touch to the non-real complex numbers which are added to $\mathbb Q$ via extensions fields. However completion of $\mathbb ...
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1answer
31 views

Trouble with a proof: $(p^n - 1 , e)=1$ for $e\in \mathbb{N}$, p prime

I'm having trouble understanding a proof. The Lemma states: For every natural number $e$ there are infinitely many prime powers $q$ with $(q-1,e)=1$. The prove is as follows: Write $e=2^km$, m odd. ...
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0answers
47 views

Transitivity of discriminant for flat algebras

Let $A$ be an finite flat $R$-algebra and $A'$ be an finite flat $A$-algebra such that it is also finite flat as an $R$-algebra. Then we have a notion of discriminant ideals ...
4
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1answer
38 views

Furstenberg theorem and twin primes

The theorem of Furstenberg showing there exists infinitely many primes (and variants, including those stripping away the topological side of things) has been discussed several times on MSE, e.g. in ...
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0answers
14 views

square classes of quadratic extensions of 2-adic fialds

I have a question about square classes of quadratic extensions of 2-adic fields. I appreciate anybody help me to understand. Why all elements of $1+\mathfrak{p}^5$ are square in ...
2
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1answer
23 views

Bibilography: Riemann's hypothesis and positive semi-definite billinear forms

This is a bibliography request: I remember browsing through a book, some years ago, in a library, in which Riemann's hypothesis was proved over some type of fields (I cannot remember what type), the ...
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2answers
65 views

Find the prime number [on hold]

Find all prime numbers $a,b,c$ and positive integers $k$ satisfying the equation $a^2 + b^2 + 16c^2=9k^2+1$. I tried but I didn't came to any result.
2
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1answer
38 views

Does a bijection from the reals to the any binary form?

It is fairly simple to store all rational numbers in a binary format (not base 2) (a language composed of only 1s and 0s, no . marking) by simply storing one integer, a seperator, and another integer. ...
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0answers
23 views

How many tiles are Symmetrical? [on hold]

We have a tape of type $1 * 2015$ had tile from tiles unit square in four different colors so as not exceed two tile of the same color (tile unit square, any tile from type $1*1$) How many tiles are ...
3
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2answers
75 views

$\log \log (\alpha)$ transcendental??

$\log \log (\alpha)$ transcendental?? ($\alpha$ algebraic $\neq 0$ and $1$) I supposed $\log \log (\alpha)=\beta$ , $\beta$ transcendental. Then $\log(\alpha)=e^{\beta}$ and it is know $e^{\beta}$ is ...
12
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2answers
131 views

Sum of Reciprocals of Primes in Imaginary Quadratic Field Diverges (2014 Miklós Schweitzer)

Problem 5 of the 2014 Miklós Schweitzer states: Let $\alpha$ be a non-real algebraic integer of degree two, and let $P$ be the set of irreducible elements of the ring $\mathbb{Z}[\alpha]$. Prove that ...
2
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0answers
32 views

Extend a map to a 1-cocycle

Let $\Gamma=PSL(2,\mathbb{Z})$ be the modular group with the usual presentation $\Gamma=\langle S,U,T|\ S^2=U^3=1, T=US\rangle$ where ...
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0answers
18 views

I attempt integrate another factor 2 in the definition of even perfect numbers

I use the method display by Florian in [1] (in true both statments of this problem are due to Florian at 99%) to compute from $\sigma(2n)-(\sigma(n)+\sigma(n))=2^p$ (where $\sigma$ is the sum of ...
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0answers
28 views

What is general Riemann's Hypothesis? [duplicate]

What makes it so important in analytic number theory?
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0answers
36 views

Why zero to the zero power is 1? [duplicate]

The google calculator say that $0^0=1$. I'm confused. It's well-known $0^0$ is undefined.