I noticed that the Community user can create tags. For example, the Community user  the  on Stack Overflow. When does the Community user create a tag?
On September 29th, I created the  tag for  Today, while checking the tag description, I saw that the  seems to be .  Why is that? Why has the Community user "stolen" the spot as author of the tag?
Can mobs go through doors? I was wondering if mobs can go through doors or not. It's the difference between me just putting up a door to my house, or putting up dirt instead. Digonalizable Polynomial Matrix For any polynomial $p(x) = a_0 + a_1x + · · · + a^kx^k$ and any square matrix A, $p(A)$ is defined as $p(A) = a_0I + a_1A + · · · + a_kA^k$. Show that if v is any eigenvector of A and $χ_A(x)$ is the characteristic polynomial of A, then $χ_A(A)v = 0$, Deduce that if A is diagonalizable then $χ_A(A)$ is the zero matrix.  I got that $p(\lambda)$ is the eigenvalue of $p(A)$ and if A is diagonalizable then $χ_A(x)$ is the zero matrix since p(A) is similar to its diagonal matrix p(D)  $$p(D) = a_nD_n + · · · + a_1D + a_0I$$  =  $\begin{matrix} p(\lambda_1) &amp;0&amp;...&amp;0\\0&amp; p(\lambda_2)&amp;...&amp; 0 \\ ...&amp;...&amp;...&amp;...\\0&amp;0&amp;... &amp; p(\lambda_n) \end{matrix}$ Python provides the "*" operator for unpacking a list of tuples and giving them to a function as arguments, like so:  args = [3, 6] range(*args)            # call with arguments unpacked from a list   This is equivalent to:  range(3, 6)   Does anyone know if there is a way to achieve this in PHP? Some googling for variations of "PHP Unpack" hasn't immediately turned up anything.. perhaps it's called something different in PHP? I am writing a document using LaTeX and generating PDF.  Can anybody tell me how I can generate the PDF metadata, e.g. author or title, from LaTeX?  On Windows XP, I am using MikTex's texify to generate the PDF.  On linux, I am using pdflatex to generate the PDF.  Any answers for either platform would be much appreciated! Word for people who live in the same city What are the people who live in the same city are called? Any words for that? I want to use it in the following context:      I and my ____ are happy. Replace strings in a file based on a list of strings and a list of corresponding replacements Use chown to set the ownership of all a folder's subfolders and files? Do you use "a" or "an" before acronyms / initialisms? 99% of the time, I'm clear on when I should use "a" versus "an." There's one case, though, where people &amp; references I respect disagree.  Which of the following would you precede with "a" or "an," and why?   FAQ FUBAR SCUBA   [Note: I've read the questions  and , but the rules given there don't necessarily apply here.]    [Edited to add]  Here's a shorter (and hopefully clearer) version of the question…  In written English, which is correct (and why): "a FAQ" or "an FAQ"?  Some references with differing opinions:   an: the  and  a: the Microsoft Manual of Style for Tech Publications, 3e either: the  and I have recently installed lubuntu 11.10 on my old laptop (acer aspire 5315 celeron) and observed that fan is not working properly on lubuntu side.I find it strange that it is working perfectly under window vista.   How could I solve this problem? How to force Wine into acting like 32-bit Windows on 64-bit Ubuntu? What do you call a person who does/thinks the opposite of the crowd for just that reason? Such a person does not hold in high regard the decisions taken by a group (not a team) of people. She believes that groups tend to be anarchic and don't serve their purpose.  An example would be - for outings with friends, this person will not like planning it with the group since they will mess it up.  Therefore, this person has convinced herself that when more people are involved with something, it will be worse. She distrusts crowds instinctively basically. Why does Hermione say she hadn't used a memory charm before? After the wedding, Hermione has to use a memory charm on two Death Eaters, where she states that she has never done it before, but she knows the theory. However, she states that before she left on her adventure, she made her parents forget her, and move to Australia. Is this a contradiction, or is there an explanation? Call to getLayoutInflater() in places not in activity How can I calculate the R-squared of a regression with arima errors using R? If I have an arima object like a:  set.seed(100) x1 &lt;- cumsum(runif(100)) x2 &lt;- c(rnorm(25, 20), rep(0, 75)) x3 &lt;- x1 + x2  dummy = c(rep(1, 25), rep(0, 75))  a &lt;- arima(x3, order=c(0, 1, 0), xreg=dummy) print(a)   .  Series: x3  ARIMA(0,1,0)                      Call: arima(x = x3, order = c(0, 1, 0), xreg = dummy)   Coefficients:         dummy       17.7665 s.e.   1.1434  sigma^2 estimated as 1.307:  log likelihood = -153.74 AIC = 311.48   AICc = 311.6   BIC = 316.67   How do calculate the R squared of this regression? What is the name of this kind of character illustration? I have seen lots of UI designer nowadays including this kind of illustration i want to know the name of this style so that i can also learn and try this in my designs. My question isn't how they receive the energy to jump, but why.  When someone views an element's emission spectrum, we see a line spectrum which proves that they don't exist outside of their orbitals (else we would see a continuous spectrum).  Electrons can be released in the form of beta decay, thus proving that they are capable of traveling outside of orbitals contrary to the statement my teacher said that they stay within orbitals. Then, to add to the confusion, the older model of rings floating around a nucleus has, from what I can tell, been outdated, which would support this model. My teacher's explanation was that the electrons made a quantum jump of some kind. How do electrons move between orbitals or do we know how they jump, excluding the reason that energy causes them to jump, and why are positrons formed sometimes instead of electrons in Beta decay?  When I'm asking "how do electrons jump" I would like to know how an electron can jump between each orbital such as how it moves and how it knows where to jump since it appears to be a jump where the electron doesn't slow into a orbital position. Specifically how they jump what is this Atomic electron transition, I understand that they jump and that they do this through absorbing and releasing energy but what is this Atomic electron transition other than what is already on the wikipedia article . For $a,b,c>0$, prove that $\frac{a^2}{b}+\frac{b^2}{c}+\frac{c^2}{a}\ge a+b+c+\frac{4(a-b)^2}{a+b+c}$ Why are some faces in my mesh darker? While rendering a mesh with smooth shading on, I get a dark region/shadow on certain faces. The effect is more evident when smooth shading is applied to a mesh containing ngons, with the ngons turning black when rendered.   The blackening effect is visible in the viewport too.  How can I solve this problem? Was V'ger responsible for the creation of the Borg? I remember reading somewhere a theory that  (the being that the Voyager probe had become in Star Trek: The Motion Picture) was somehow responsible for the creation of the Borg.  Is this canonical?  Where does the theory come from?  And how exactly did it go down? When I place a multipage pdf file into InDesign CC, the pages go outside of my document settings, making this function useless.  What do I have to do to make the placed  pdf pages go within my document settings, which in this case is 11 in. Length X 8.5 in. width, .5 in. margins on all sides, with two columns per page. I would greatly appreciate an answer to this, Thank you.