An Expression for $\log\zeta(ns)$ derived from the Limit of the truncated Prime $\zeta$ Function - MathOverflow most recent 30 from http://mathoverflow.net2013-05-19T17:24:09Zhttp://mathoverflow.net/feeds/question/119210http://www.creativecommons.org/licenses/by-nc/2.5/rdfhttp://mathoverflow.net/questions/119210/an-expression-for-log-zetans-derived-from-the-limit-of-the-truncated-primeAn Expression for $\log\zeta(ns)$ derived from the Limit of the truncated Prime $\zeta$ Functiondraks2013-01-17T20:47:55Z2013-01-24T20:57:09Z
<p>I think, <a href="http://math.stackexchange.com/q/115230/19341" rel="nofollow">here</a>, I found
$$
P_x(s)=\sum_{p < x} \frac{1}{p^s} =\sum_{n=1}^{\infty}\frac{ \mu (n)}{n}
\sum_{z\in{1,\rho}}(-1)^{1-\delta_{1z}}
\left[
{\rm li}(t^{\frac zn-s})
\right]^{x}_2
\tag{7}
$$</p>
<p>where $\rho$ are <strong>all</strong> the zeros (trivial and non-trivial) of $\zeta$ function. See the linked question for more detail, corrections are welcome.
Further we know, that
$$
P(s)=\sum_{n> 0}\frac {\mu(n)}n{\log\zeta(ns)} .
$$</p>
<p>So my question is </p>
<blockquote>
<p>If
$\lim_{x\to \infty} P_x(s)=P(s) $
then
$$
\log\zeta(ns)=\lim_{x\to \infty}
\sum_{z\in{1,\rho}}(-1)^{1-\delta_{1z}}
\left[
{\rm li}(t^{\frac1n( z-ns)})
\right]^{x}_2
?
$$</p>
</blockquote>
<p>What I got so far is:</p>
<ul>
<li><p>Could $ \displaystyle \log \zeta(s) = s \int_0^\infty \frac{\pi(x)}{x(x^s-1)}\,dx $ be useful somehow?</p></li>
<li><p><a href="http://math.stackexchange.com/a/285413/19341" rel="nofollow">Thanks to robjohn</a> it possible to see that both coincide at least some special values:<br>
If $ns=1$ or $ns=\rho$, one addend in the sum diverges like $\lim_{x\to\infty} \log\left(\frac{\log(x)}{\log(2)}\right)=\infty$. So we get
$$
\begin{eqnarray}
ns=1: & \log(\zeta(1)) &=& +\infty\
ns=\rho: & \log(\zeta(\rho)) &=& -\infty
\end{eqnarray}
$$</p></li>
<li><p>I looked at the series expansion at $s=0$ for ${\rm li}(x^{\frac1n(z-ns)})=$
<a href="http://tinyurl.com/b57ga7j" rel="nofollow">${\rm Ei}((\frac zn-s)\ln(x))$</a> and <a href="http://tinyurl.com/a3tvnml" rel="nofollow">$\log\zeta(ns)$</a>. Assuming I'm not wrong, you'll get the following when you compare the linear terms
$$
\color{grey}{ins}\log(2\pi) \overset{?}{=}
\color{grey}{ins}
\lim_{x\to \infty}\sum_{z\in{1,\rho}}(-1)^{\delta_{1z}}
\left[ \frac{ t^{\frac{z}n}}{z}\right]_2^x ,
$$
which looks a little irritating, since the RHS has to be independent of $x$ an $n$. Does this show that it's wrong at all?</p></li>
</ul>