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1 vote
1 answer
140 views

Given the primes, how many numbers are there?

I have a concrete question and a more abstract version of the same. There are lots of theorems that take information on the number of elements and translate it to information on the primes; I’m ...
Charles's user avatar
  • 32.3k
-1 votes
1 answer
70 views

How to give this sum a bound?

Let $x,y\in\mathbb{Z},$ consider the sum below $$\sum_{x,y\in\mathbb{Z}\\ x\neq y}\frac{1}{|x-y|^{4}}\Bigg|\frac{1}{|x|^{4}}-\frac{1}{|y|^{4}}\Bigg|,$$ is there anything I could do to give this sum a ...
Chang's user avatar
  • 329
7 votes
1 answer
711 views

What's the easiest way to prove the Riemann Zeta function has any zeros at all on the critical line?

I learned in my intro to complex analysis class that the Riemann Zeta has trivial zeros at the negative even integers; this follows from the Riemann Zeta Reflection identity and the behavior of the $\...
Faraz Masroor's user avatar
2 votes
1 answer
53 views

The "Euler Product formula" for general multiplicative functions

For the totient function $\phi$, we have the well known "Euler's product formula" (as named on Wikipedia) $$\phi(n) = n \prod_{p | n} \left( 1 - \frac{1}{p} \right)$$ This is easy to show ...
Instagram-creative_math_'s user avatar
1 vote
0 answers
57 views

Periodic zeta function

Let $e(x)=e^{2\pi ix}$ and let $$F(x,s)=\sum _{n=1}^\infty \frac {e(nx)}{n^s}$$ be the periodic zeta function. What is the functional equation for the periodic zeta function ?: I can find a statement ...
tomos's user avatar
  • 1,662
1 vote
1 answer
55 views

$H(x)$ approximates $\pi(x)$ pretty well. But what are the drawbacks, when compared with Riemann's $R(x)$?

I'm aware of the Gram series which is equivalent to $R(x)$ (Riemann prime counting function): $$ R(x)=\sum_{n=1}^\infty \frac{\mu(n)}{n}li(x^{1/n}). $$ Over the interval $x=2$ to $x=10^4$ the average ...
zeta space's user avatar
3 votes
0 answers
45 views

Number of representations of an integer by a binary quadratic form

In a paper by Heath-Brown, upon having to estimate the number of solutions $(x,y)\in\mathbb Z^2\cap[-B,B]^2$ to the equation $Q(x,y)=k$ with $Q$ an integer-coefficient non-degenerate quadratic form ...
Simon Pitte's user avatar
0 votes
0 answers
39 views

Normal Order of Distinct Prime Factor $\omega(n)$

Define $\omega(n)$ as number of distinct prime factors $n$ has, that is if $n=p_1^{a_1}... p_k^{a_k}$, then $\omega(n)=k$. It is commonly understood that normal order of $\omega(n)$ is $\log\log(n)$, ...
spicychicken's user avatar
1 vote
1 answer
63 views

Write the sum in terms of the Riemann zeta function

I believe it is a question from JHMT. Write the sum $\sum_{a=1}^\infty\sum_{b=1}^\infty\frac{gcd(a,b)}{(a+b)^3}$ in terms of Riemann zeta function. The answer should be $-Z(2)+\frac{Z(2)^2}{Z(3)}$...
user1200034's user avatar
1 vote
1 answer
87 views

The sum $f(x)= \sum_{p \le x} e^{\frac{1}{p\log p}}$ is very close to $\pi(x)$. Why is that?

The prime counting function $\pi(x)$ counts the number of primes less than a given $x$. There are other counting functions like Chebyshev's functions which count sums of logarithms of primes up to a ...
zeta space's user avatar
1 vote
1 answer
72 views

A special kind of Poisson summation formula

There is a Poisson summation formula as follows: Let $V$ be a smooth function with compact support on $\mathbb{R}$. For $X > 1$ and $q > 1$, we have $$\sum_{n\equiv a~\mathrm{ mod }~q}{V}\left( ...
XUSEN's user avatar
  • 39
4 votes
0 answers
127 views

If $\zeta(5)=\frac{a}{b}\in\mathbb{Q}$ then $b\neq p^k$

If $\zeta(5)=\frac{a}{b}\in\mathbb{Q}$ then prove that $b\neq p^k$ where $p$ is any prime and $k\in\mathbb{N}$ Take $a,b\in\mathbb{N}$ such that $(a,b)=1$. Now if $b=p^k$ then $$p^k\zeta(5)=a$$ So, by ...
Max's user avatar
  • 928
4 votes
1 answer
140 views

Closed form of $\int_{(0,1)^5} \frac{xyuvw}{(1-(1-xy)u)(1-(1-xy)v)(1-(1-xy)w))}\, dx\,dy\,du\,dv\,dw$

I need closed form for the integral $$I:=\int_{(0,1)^5} \frac{xyuvw}{(1-(1-xy)u)(1-(1-xy)v)(1-(1-xy)w))} \, dx\,dy\,du\,dv\,dw$$ Then $$0<I<\int_{(0,1)^5} \frac{1}{(1-(1-xy)u)(1-(1-xy)v)(1-(1-xy)...
Max's user avatar
  • 928
4 votes
1 answer
192 views

Does this function in $3$b$1$b has a name?

I was watching this video from $3$Blue$1$Brown channel, at minute 21:00 he introduced the following function: $$ \chi(n)= \begin{cases} 0 & \text{if } n=2k \\ 1 & \text{if } n=4k+1\\ -1 & \...
MR_BD's user avatar
  • 6,100
0 votes
0 answers
94 views

Expressing a function in terms of the nontrivial zeros of the Riemann zeta function

Consider the function $\phi(x)$: $$ \phi(x)=\sum_{n=1}^{\infty}\frac{\mu(n)}{n^{2}}\left(\left\{ \frac{x}{n}\right\}-\frac{1}{2}\right)$$ $\left\{\cdot\right\}$ being the fractional part function. ...
Mohammad Al Jamal's user avatar

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