Book series in which a world is divided into zones and people get transfigured when going from the hub to a zone
Looking for old book, SF, artificial world, different zones for different species that visitors "inhabit"
Does there exist a bijective $f:\mathbb{N} \to \mathbb{N}$ such that $\sum f(n)/n^2$ converges? We know that $\displaystyle\zeta(2)=\sum\limits_{n=1}^{\infty} \frac{1}{n^2} = \frac{\pi^2}{6}$ and it converges.        Does there exists a bijective map $f:\mathbb{N} \to \mathbb{N}$ such that the sum $$\sum\limits_{n=1}^{\infty} \frac{f(n)}{n^2}$$ converges.      If our $s=2$ was not fixed, then can we have a function such that $\displaystyle \zeta(s)=\sum\limits_{n=1}^{\infty} \frac{f(n)}{n^s}$ converges Insert Login IP Ranges using apex in salesforce Is it possible to insert to Login IP ranges via apex? Prove that if a function $f$ has a jump at an interior point of the interval $[a,b]$ then it cannot be the derivative of any function. Prove that if a function $f$ has a jump at an interior point of the interval $[a,b]$ then it cannot be the derivative of any function.  I know that for $f$ is differentiable in $(a,b)$ and that it has one-sided derivative $f_+' (a)≠f_-' (b)$ at the endpoints. If $C$ is a real number between $f_+' (a)$  and $f_-' (b)$, then there exists $c∈(a,b)$ such that $f' (c)=C $. How can I use this to prove the above? Are there any organised resources available from where I can begin my quantum computing studies? I am a computer science student and am currently searching for resources from where I can learn about quantum computers, quantum computing models, their working principles, their gates and some simple quantum algorithms. I want to update Acrobat Reader for Firefox, but the download has the .bin extension. How can I install it? The PS3 version of Portal 2 comes with a code to link it to a Steam account. Apparently this allows you to play on both the PC and PS3 with one purchase.  Can this be used to play co-op between the two platforms? Why do we need to fork to create new processes? "The volume boot has only 0 bytes disk space remaining" After a recent update, I'm getting an alert saying:  The volume boot has only 0 bytes disk space remaining   But my computer has plenty of HD space free. Does anyone know how I resolve this. (If it's relevant, I'm using the whole disk encryption feature of the alternate install image for Ubuntu 12.04). I came across this statement while studying electric currents and I am confused:  "There is no electric field inside a conductor. Hence no current can flow through it".  Is there a fallacy in this statement?  Any help would be appreciated.  The conductor being discussed is ideal. What is the driving force for the current in this case? How can I bypass Activation Lock? Can a person residing in Singapore on a 5-month Employment Pass apply for a Schengen visa? I used node textures in a mesh I exported to .FBX.  I then imported it into Unreal Engine 4 and it didn't import any textures; I clicked the Upload Textures option in Unreal Engine.  Is there something I'm doing wrong or is it Blender? Prove that $$\cos(\pi/11)+\cos(3\pi/11)+\cos(5\pi/11)+\cos(7\pi/11)+\cos(9\pi/11)=1/2$$ using Euler's formula.  Everything I tried has failed so far.  Here is one thing I tried, but obviously didn't work. $$\Re e \{e^{\frac{\pi}{11}i}(1+e^{\frac{2\pi}{11}i}+e^{\frac{4\pi}{11}i}+e^{\frac{6\pi}{11}i}+e^{\frac{8\pi}{11}i}) \}=\frac{1}{2}$$ $$\Re e \{e^{\frac{\pi}{11}i}(1+\sqrt[11]{e^{2\pi i}}+\sqrt[11]{e^{4\pi i}}+\sqrt[11]{e^{6\pi i}}+\sqrt[11]{e^{8\pi i}}) \}=\frac{1}{2}$$ $$\Re e \{e^{\frac{\pi}{11}i}(1+\sqrt[11]{1}+\sqrt[11]{1}+\sqrt[11]{1}+\sqrt[11]{1}) \}=\frac{1}{2}$$ $$\Re e \{5e^{\frac{\pi}{11}i} \}=\frac{1}{2}$$ $$5\cos(\frac{\pi}{11})=\frac{1}{2}$$ Which isn't true :D  Thanks in advance Key uses weak digest algorithm I'am getting this kind of message while updating my ubuntu 16.04 LTS:  W: http://dl.google.com/linux/chrome/deb/dists/stable/Release.gpg: Signature by key 4CCA1EAF950CEE4AB83976DCA040830F7FAC5991 uses weak digest algorithm (SHA1) W: http://dl.google.com/linux/chrome/deb/dists/stable/Release.gpg: Signature by key 3B068FB4789ABE4AEFA3BB491397BC53640DB551 uses weak digest algorithm (SHA1)   Can anyone help me? Modern movie where rich people can buy a personal assistant that sit in a small egg This is a modern movie and rich people can buy this egg with a personal assistant. It's an actual person in it (or a person's mind). I believe it can even operate a toaster.  I believe later in the movie, a person (or their mind) can be transferred to such an egg. As a punishment, they increase the speed of time inside that egg to make the person inside the egg bored to death, so to speak. How to stop HTTPS requests for non-ssl-enabled virtual hosts from going to the first ssl-enabled virtualhost (Apache-SNI) I hope that title is clear.  How do I prevent HTTPS requests for non-ssl-enabled virtual hosts from going to the first ssl-enabled virtualhost (setup is Apache-SNI).  For example, using my abbreviated config below, requests for https://example.com (a non-ssl vhost) are being served by Apache at the ssl-enabled vhost https://example.org. I'd like to disable that behavior and possibly reply with the appropriate HTTP response code (unsure of what that is).  It may not even be possible, but I thought I'd ask.  # I actually have a SNI setup, but it's not demonstrated here. # I don't think it's relevant in this situation.  NameVirtualHost *:80 NameVirtualHost *:443  &lt;VirtualHost *:80&gt;     ServerName example.org &lt;/VirtualHost&gt;  &lt;VirtualHost *:443&gt;     ServerName example.org &lt;/VirtualHost&gt;  &lt;VirtualHost *:80&gt;     ServerName example.com &lt;/VirtualHost&gt;   EDIT: Maybe a mod_rewrite rule in the first ssl-vhost? Why can't I catch Pokemon in Pokemon Go anymore? I'm level 10 on Pokemon Go. I've caught at least 150 Pokemon, and had no problems. Now, every time I try to catch a Pokemon, no matter the level, it just rolls twice in the pokeball, breaks free, then runs away. Can anyone provide some insight on how to fix this problem? I know that there is a precise solution of the equations:  \begin{align}     x + a &amp; = 0 \\     x^2 + a\cdot x + b &amp; = 0 \\     x^3 + a\cdot x^2 + b\cdot x + c &amp; = 0 \\     x^4 + a\cdot x^3 + b\cdot x^2 + c\cdot x + d &amp; = 0 \end{align}  Why there is no solutions for equation of degree $\ge 5$? Euclidean geometry in non-inertial frame HTTP request parameters are not available by request.getAttribute()