Can we detect gravitational waves generated from inside the event horizon of a black hole?
How does gravity escape a black hole?
Can Hooke's law be derived? Can we derive  from the theory of elasticity? I know it is not a fundamental law and therefore can be derived from more basic considerations. What is the difference between a teaching assistant and an instructor? It seems to me that the terms "Teaching Assistant" and "Instructor" refer to a variety of positions. At some places, a teaching assistant is responsible for things like helping the actual lecturer by handing out papers, grading homework, etc., and instructors hold recitation sessions.  At other places, I saw the term "instructor" referring to the lecturer giving the course, while a teaching assistant is the person doing anything else (recitations, grading etc.).  Is there some widely accepted definition of the two positions?  For context: The question arose because I wasn't sure whether I'm using the correct terms in my CV -- I am a math graduate student, and I would like to make a distinction between jobs in which I only graded course assignments/final exams, and courses in which I held recitation classes* (and also participated in grading the final exams). Is it OK to use "Instructor" for the latter? What should the former be referred to as?  *In the course I'm currently teaching, the recitations are planned and written by the ones giving them (without the professors' supervision). Also, the people giving the recitations are not necessarily grad students (some already hold a PhD). I'm elaborating on that because from what I've seen, some of it could be relevant for the definition of the job. Rogue DHCP Server Can't be found Over the last 3-4 weeks I have been trying to find a rogue DHCP server on my network but have been stumped! It is offering IP Addresses that do not work with my network, so any device that needs a Dynamic Address is getting one from the Rogue DHCP and then that device stops working. I need help to find and destroy this thing! I think it might be a Trojan of some sort.  My Main Router is the only valid DHCP Server and is 192.168.0.1 which offers a range of 192.160.0.150-199, and I have this configured in my AD as Authorized. This ROGUE DHCP claims to be coming from 192.168.0.20 and offering an IP Address in the range of 10.255.255.* which is messing up EVERYTHING on my network unless I assign a static IP Address to it. 192.168.0.20 does not exist on my network.  My network is a single AD Server on Windows 2008R2, 3 other physical servers (1-2008R2 and 2 2012R2) about 4 Hypervisor VM's, 3 laptops and a Windows 7 box.  I can't ping the rogue 192.160.0.20 IP, and I can't see it in the ARP -A output, so I can't get its MAC address. I'm hoping that someone reading this post has come across this before. Proving $\left(1+\dfrac{1}{1^3}\right)\left(1+\dfrac{1}{2^3}\right)\cdots\left(1+\dfrac{1}{n^3}\right)<3$ for all positive integers $n$ Prove that $\left(1+\dfrac{1}{1^3}\right)\left(1+\dfrac{1}{2^3}\right)\cdots\left(1+\dfrac{1}{n^3}\right)&lt;3$   for all positive integers $n$   This problem is copied from Math Olympiad Treasures by Titu Andreescu and Bogdan Enescu.They start by stating that induction wouldn't directly work here since the right hand side stays constant while the left increases.They get rid of this problem by strengthening the hypothesis.$$\left(1+\dfrac{1}{1^3}\right)\left(1+\dfrac{1}{2^3}\right)\cdots\left(1+\dfrac{1}{n^3}\right)\le3-\dfrac{1}{n}$$ and then proceed by induction.  The problem is that I can't find a motivation for the above change.I mean,we could have subtracted a lot of things from the RHS but what should nudge us to try $\dfrac{1}{n}$?The rest of the proof is quite standard,but I can't see how I am supposed to have thought of it.Is it just experience?Or is it a standard technique?A little guidance and motivation will be appreciated. There is a nice property of normal spaces, namely, closed disjoint subsets can be separated by continuous functions into $\mathbb R$.   Then you ask yourself, what about Hausdorff spaces?, are all Hausdorff spaces completely Hausdorff?   Well, if we choose our separating space $X$, that is, the space such that for any Hausdorff $Y$ and any distinct $a,b\in Y$ there is some continuous $f:Y\rightarrow X$ with $f(a)\neq f(b)$, to be completely regular and Hausdorff, this cannot happen by an example of E. Hewitt, Hewitt’s Condensed Corkscrew, call it $\mathbb H$; as any continuous function from $\mathbb H$ into $\mathbb R$ is constant, and any Hausdorff completely regular space $X$ can be embedded into a product of closed intervals $\prod_{i\in I}[0,1]$, and thus any continuous $f:\mathbb H\rightarrow X\subseteq \prod_{i\in I}[0,1]$ is constant, as each $\pi_i\circ f$ is constant, so our candidate to be the separating space $X$ cannot even be $[0,1]$.  My question is, does there exist a Hausdorff space $X$ such that for all Hausdorff spaces $Y$, and any distinct $a,b\in Y$ there exists a continuous $f:Y\to X$ such that $f(a)\neq f(b)$?  Thanks. Travel on a Schengen visa stating EEA family member without spouse? Interpretation of interaction term What are the alternatives to Notepad++ on Ubuntu? How do I pipe terminal standard output (stdout) to the clipboard? For example,   Say I want to list the contents of a folder and directly paste them into a chat window for a friend to see.    I realize I could do ls &gt; filename.txt to create a file (filename.txt) with those contents; I'd then have to open or print the file and manually select and copy the text block (which can be annoying/tedious.)  I clearly could also select and copy the output of ls directly from within the terminal window.  It would be much faster/easier to simply pipe standard output to the clipboard.  What terminal command allows me to do this? I am trying to auto-mount my NFS drives, but it doesn't work too well sadly.  What does work is mounting from CLI:  me@client:/$ sudo mount 192.168.178.4:/mountdir /mnt/mountdir me@client:/$ mount -t nfs 192.168.178.4:/mountdir on /mnt/mountdir type nfs (rw,addr=192.168.178.4)   when I try to add mountdir in the fstab, I cannot mount it due to "protocol not supported" (which seems strange as I can mount it)  $ sudo mount films_d3 mount.nfs: Protocol not supported   So there might be something wrong with my fstab entry. This is my current entry:  192.168.178.4:/mountdir /mnt/mountdir  nfs auto,_netdev,noatime,nolock,bg,nfsvers=4,intr,tcp,actimeo=1800 0 0   During startup I also get this error twice: I was trying to fix the mount-from-fstab first, then worry about that, but nevertheless this might be a different problem:  init: idmapd-mounting (/mnt/kazemat/films_d3) main process (445) killed by TERM signal   This seems to be before the eth0 is initialised, while I thought the "_netdev" option would make the entry wait for the network to be up?  can anywone see the mistake in my fstab entry? What is the best way to add options to a select from a JavaScript object with jQuery? What is the best method for adding options to a &lt;select&gt; from a JavaScript object using jQuery?  I'm looking for something that I don't need a plugin to do, but I would also be interested in the plugins that are out there.  This is what I did:  selectValues = { "1": "test 1", "2": "test 2" };  for (key in selectValues) {   if (typeof (selectValues[key] == 'string') {     $('#mySelect').append('&lt;option value="' + key + '"&gt;' + selectValues[key] + '&lt;/option&gt;');   } }   A clean/simple solution:  This is a cleaned up and simplified :  $.each(selectValues, function(key, value) {      $('#mySelect')           .append($('&lt;option&gt;', { value : key })           .text(value)); });   Changes from matdumsa's: (1) removed the close tag for the option inside append() and (2) moved the properties/attributes into an map as the second parameter of append(). Rewrite rules goes away Is there a way to scale up the bevel object on one end of a curve, a little bit over each point?  I notice the vertex "weight" slider will tweak how much influence each vertex has on the others, is there something like this that can scale the bevel object up a little bit?  Preferably with the option to constrain X,Y,Z independently How to remove the URL from the printing page? I want to remove the URL that gets printed on the bottom of the page.   like:  yomari.com/.../main.php?sen_n   How can it be omitted or prevent from getting printed?  To be more specific, is there any way I can prevent the page URL, date and the page title being printed along, while printing the web page? How to fix broken taskbar icons in Windows 7 Consider a sequence of $n$ Bernoulli trials with $P(\text{success})=p$. Let $X_i$ and $X_j$ be indicator variables of the number of "success" in $i$th and $j$th runs. Given the total number of success was $m$, $m&lt;n$. I am asked to compute the correlation coefficient for $X_i$ and $X_j$.  Now I know the formula for correlation coefficient, but to compute the co-variance I will need to find $E(X_i)$ and $E(X_j)$ first. By definition does $E(X_i)=p_i$ and $E(X_j)=p_j$? I feel this seems a bit too easy but I can't see whats wrong with it. A correct preposition - account closed due/by/at 12th of May Is it possible to check out subdirectories of a repository in Git?  Imagine I am setting up a new WordPress installation. I will create two new directories for my plugin and theme customization:   wordpress/wp-content/plugins/myplugins/  wordpress/wp-content/themes/mytheme/   I want to maintain these directories via Git. In Subversion, I would accomplish this by having trunk/myplugins/ and trunk/mytheme/ directories and checking out subdirectories. Does Git have a way to accomplish the same task using a single repository?  I could just be missing the boat on some Git paradigm, as a long time SVN user with little exposure to Git.  Edit:  storing different content is an interesting way to handle this. Ignore citations in captions in list of figures when numbering When using the \cite command in figure captions and the ieeetr bibliography style, then  BibTeX numbers the citations as appearing earlier than they do in reality (i.e. the first citation in the document ends up being [42]).  Is there any way to get BibTeX to ignore the \listoffigures section when numbering? Is "data" treated as singular or plural in formal contexts?