I had a situation earlier where I was trying to help someone with an issue. If I upvote all their questions so we can move it to chat, is that ok? They did not have enough rep to chat.
I just noticed that I lost a bunch of points from my reputation score, and I used the "reputation" tab on my user profile page to try and track down the cause.  During my investigation, I noticed there was an unusual event of type "reversal". In the normal place of a question title, it says "voting corrected".     What does this mean, and what caused it?  Did I do something wrong? Why did I lose all of that reputation? Is the system punishing me for leaving too many good answers?  Is there any way to earn it back?
Virtualbox: OS cannot use the new extended disk space (.vdi) I am running Virtualbox. I increased the size of my hard disk (.vdi) from 10G to 15G. Now when I start my Mint vm, the hard disk reports as 7.5g (df) even though i extended it (fdisk -l). I am not sure what is the problem. Can anyone point me the problem?  $ df -h Filesystem      Size  Used Avail Use% Mounted on /dev/sda1     &gt;&gt;7.5G&lt;&lt; 7.1G   61M 100% / udev            1.5G  4.0K  1.5G   1% /dev tmpfs           581M  888K  581M   1% /run none            5.0M     0  5.0M   0% /run/lock none            1.5G   88K  1.5G   1% /run/shm  $ sudo fdisk -l Disk /dev/sda: &gt;&gt;16.1 GB&lt;&lt;, 16106127360 bytes 255 heads, 63 sectors/track, 1958 cylinders, total 31457280 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000c55a4     Device Boot      Start         End      Blocks   Id  System /dev/sda1   *        2048    15728639     7863296   83  Linux /dev/sda2        15730686    16775167      522241    5  Extended /dev/sda5        15730688    16775167      522240   82  Linux swap / Solaris  $ vboxmanage showhdinfo mint.vdi UUID:                 a94931b9-673c-440a-ab6b-2c3eedd0cf93 Accessible:           yes Logical size:         15360 MBytes Current size on disk: 7806 MBytes Type:                 normal (base) Storage format:       VDI Format variant:       dynamic default Location:             /opt/virtualization/vm/mint.vdi function $f(x)=x^{-(1/3)}$ , please check whether my solution is correct? Let $f(x)=x^{-(1/3)}$ and $A$ denote the area of region bounded by $f(x)$ and the X-axis, when $x$ varies from -1 to 1. Which of the following statements is/are TRUE?   f is continuous in [-1, 1] f is not bounded in [-1, 1] A is nonzero and finite     I try to explain :    graph is  :     False , since left limit is not equivalent to right limit. True , since  f(x) rises to $infinite$ at $x=0$. True , since we can calculate it by doing integrating the function I know of 2 basic kinds of default web icons for websites:   : place an .ico formatted file at the root of your site named favicon.ico and most desktop browsers will find it and display it in various contexts (bookmarks, tabs). Can also be added in code, which allows you to specify other names and other graphics types to the file, though there are :  &lt;link rel="shortcut icon" href="/favicon.ico" /&gt; &lt;link rel="icon" href="/favicon.ico" /&gt;  : place a png formatted file called either apple-touch-icon.png or apple-touch-icon-precomposed.png at the root of your site and iPhone OS/iOS versions of Safari will pick those up and store them when the site is added to the Home Screen. Can also be added with code like:  &lt;link rel="apple-touch-icon" href="/custom_icon.png" /&gt;    Are there any other default icon graphics for a website a webmaster can include? What is a good method for short text clustering? I am working on a text clustering problem. The data contains several sentences. Is there a good algorithm which reaches high accuracy on short text?  Can you provide good references?   Algorithms such as KMeans, spectral clustering does not work well for this problem. Embedding $S_n$ into $A_{n+2}$ Can a parallel computer simulate a quantum computer? Is BQP inside NP? Collage of six photos, not Facebook Lookback movie How to sort this JSON Post Link for Tag Info Wiki's display text should be better than "unknown" The displayed text for a [Post Link] where the underlying Id corresponds to a Tag/Info Wiki (where the link redirects successfully) is just &quot;unknown&quot;. For example, if you've ever edited a tag wiki: . It would be nice if this could be better identified. When I get exceptions, it is often from deep within the call stack.  When this happens, more often than not, the actual offending line of code is hidden from me:  tmp.rb:7:in `t': undefined method `bar' for nil:NilClass (NoMethodError)         from tmp.rb:10:in `s'         from tmp.rb:13:in `r'         from tmp.rb:16:in `q'         from tmp.rb:19:in `p'         from tmp.rb:22:in `o'         from tmp.rb:25:in `n'         from tmp.rb:28:in `m'         from tmp.rb:31:in `l'          ... 8 levels...         from tmp.rb:58:in `c'         from tmp.rb:61:in `b'         from tmp.rb:64:in `a'         from tmp.rb:67   That "... 8 levels..." truncation is causing me a great deal of trouble.  I'm not having much success googling for this one:  How do I tell ruby that I want dumps to include the full stack? I'm attempting to install Ubuntu 14.04.1 (the only version I have handy) onto my old Compaq Presario R3000 (this Ubuntu was recommended for this computer). The installation has stalled at about 60% and hasn't moved in an hour.  The message at the bottom says: Configuring bcmwl-kernal-source (i386).  I have no experience with Ubuntu (or with Linux, for that matter), coming from a strictly-Windows background). Can anyone offer some advice? Union of two vector subspaces not a subspace? Is the differentiation operator an open mapping? Consider the vector spaces $C([0, 1])$ and $C^1([0, 1])$ with norm, \begin{align*} \displaystyle \|f\|_\infty=\sup_{x\in [0, 1]}|f(x)|, \end{align*} and let $T:C^1([0, 1])\to C([0, 1])$ the operator given by, \begin{align*} \displaystyle Tf=f'. \end{align*} Is $T$ defined this way an open mapping? If it's, how to prove it? I know the new SPFx will be released for Sharepoint 2016 sometime in the year 2017. But are there any plans to also bring this for Sharepoint 2013?  Are there any possibilities/hacks to add a Sharepoint app created with SPFx in the Sharepoint 2013 app catalog? What the #$@&%*! is that called? ggplot2: facet_wrap strip color based on variable in data set The first given name of an author or editor in my bibliography should be written out, but all further first names should be abbreviated (initials with a period -- and space if there are multiple first names/initials, see below). I am using style=authoryear with BibLaTeX (v. 2.7) and Biber (v. 1.7).  My bibliography looks like this:     Doe, John Arthur Kyle (2013). The secret life of John Doe.   It should look like this:     Doe, John A. K. (2013). The secret life of John Doe.   Minimal example:  example.tex  \documentclass{scrartcl}  \usepackage[ngerman]{babel} \usepackage[babel,german=quotes]{csquotes} \usepackage[backend=biber,style=authoryear]{biblatex} \bibliography{bibliography}  \begin{document}  \cite[123]{Doe} \printbibliography  \end{document}   bibliography.bib  @book{Doe,     title = {The secret life of John Doe},     author = {Doe, John Arthur Kyle},     year = {2013} }   (Worked with said versions of BibLaTeX and Biber, Texmaker (v. 4.0.3) and MiKTeX (v. 2.9.4813).)  I could not find a solution in biblatex.def and firstinits=true abbreviates all first names, including the first one. When I'm about to install a program in the terminal it wants the password:  [sudo] password for xxx:   But when I start to type my password nothing happens. What should I do? What lens focal length most closely resembles the perspective of the human eye? Suppose every subsequence of X converges to 0. Show that lim(X)=0 Question: Suppose that every subsequences of $X = (x_n)$ has a subsequence that converges to $0$. Show that $\lim(X) = 0$   My attempt:   Suppose that $\lim(X) =L \neq 0$  Let $\epsilon &gt; 0$, and let $K(\epsilon)$ be s.t. $n \ge K(\epsilon)$   then $|x_n-L| &lt; \epsilon$  let $n_k \ge k$, and then $k \ge K(\epsilon)$ and $n_k \ge k \ge K(\epsilon)$ s.t. $|x_{n_{k}}-L| &lt; \epsilon$, which is a contradiction. therefore $\lim(x) =0$