For example, "I found that LA is not an island." (Truth always)  or "I ensured them that car insurance is necessary." (Truth in past and now still)  Do I have to use "was" instead of "is" for tense agreement?
I'm describing a situation that happened in the past. To explain it, I want to use a description that is both true now and true when the situation happened.  Specifically, I want something like:     She touched me where my neck met my collarbone.   Since my neck is still attached to my collarbone (thankfully), I'm wondering if I shouldn't use the present tense here instead:     She touched me where my neck meets my collarbone.   Which is preferable, and why?
I have this statement and I need to say if it is true or false:  Let $\{a_n\}$ be a real sequence.  $$\lim_{n\to +\infty} a_n = 0 \quad \implies \quad \sum_{n=1}^{\infty}(-1)^na_n \quad \text{converges}$$  I know, from the Leibniz criterion that:     If $a_n \to 0$, $a_n$ is decreasing and positive then $\sum_{n=1}^{\infty}(-1)^na_n$ converges   From this fact I believe that the statement is false but I couldn't come up with an infinitesimal sequence that isn't decreasing and for that reason is divergent. I tried some function with $sin(\frac{1}{n})$ without any luck. Any help would be very appreciated, thank you! How do you appear offline to friends on Battle.net? I have a number of friends on my battle.net account. However, sometimes I don't want to appear online to some (or all) of them. Is there a way to be hidden from your friends on battle.net? No hair theorem for black holes and the baryon number isolated non-normal surface singularity I am looking for an isolated non-normal singularity on an algebraic surface. One obvious example occurs to me: the union of two $2$-dimensional affine subspaces of $\mathbb{A}^4$ which meet in a point. But this seems like "cheating." Can someone provide an irreducible example? How to find the square root of a permutation Observe that  $$\begin{pmatrix} 1 &amp; 2 &amp; 3 &amp; 4 &amp; 5 \\  2 &amp; 4 &amp; 1 &amp; 5 &amp; 3 \end{pmatrix} \begin{pmatrix} 1 &amp; 2 &amp; 3 &amp; 4 &amp; 5 \\  2 &amp; 4 &amp; 1 &amp; 5 &amp; 3 \end{pmatrix} =  \begin{pmatrix} 1 &amp; 2 &amp; 3 &amp; 4 &amp; 5 \\  4 &amp; 5 &amp; 2 &amp; 3 &amp; 1 \end{pmatrix},$$  so $\begin{pmatrix} 1 &amp; 2 &amp; 3 &amp; 4 &amp; 5 \\  4 &amp; 5 &amp; 2 &amp; 3 &amp; 1 \end{pmatrix}$ is the square of a permutation. More generally, how do I check if a permutation is square and how can I find its root? How do I write a short literal in C++? Very basic question: how do I write a short literal in C++?  I know the following:   2 is an int 2U is an unsigned int 2L is a long 2LL is a long long 2.0f is a float 2.0 is a double '\2' is a char.   But how would I write a short literal?  I tried 2S but that gives a compiler warning. $\mathbb{Q}^{\times}$ is the group of rational number without $0$ under multiplication, and $\mathbb{Z}^{n}$ is the free abelian group of rank $n$. Show that $\mathbb{Q}^{\times}$ not isomorphic to $\mathbb{Z}^{n}$. I tried to assume that there is an isomorphism and to get a contradiction.. didn't succeed The double cone is not a surface. How to toggle Scroll Lock in Excel 2010 without a Scroll Lock key in the keyboard I have a notebook with no Scroll Lock key (or any shortcut using the 'Fn' key).  Somehow Excel 2010 got the Scroll Lock on. I see it left down in the status bar and now I can't navigate through cells using the arrow keys, which is pretty annoying. It wasn't turned on some hours ago, so I think I must have hit some Scroll Lock toggle shortcut in Excel 2010 by mistake.  Anyone knows what hot to turn off Scroll Lock in Excel (shortcut or menu option)? Is a visa to Poland required for a Russian spouse of a Polish citizen? I am a holder of a Russian passport and my husband is a Polish citizen. We both live and work in the UK. I have received my family member of EEA national card, good for 5 years. We would like to travel to Poland together. On the website of the Polish embassy it clearly states that if we are traveling together, I do not require a visa, however in the embassy they were sure that I do need a visa. Could anyone please clarify? Plotting Population Regression Function with pgfplot I want the make the following population regression function with pgfplot.     My attempted code is  \documentclass[border=5mm]{standalone} \usepackage{pgfplots}   \begin{document}  \begin{tikzpicture}[ % Define Normal Probability Function declare function={             normal(\m,\s)=1/(2*\s*sqrt(pi))*exp(-(x-\m)^2/(2*\s^2));         }        ] \begin{axis}[     no markers   , domain=-3.2:3.2   , samples=100   , ymin=0   , axis lines*=left   , xlabel=     , every axis y label/.style={at=(current axis.above origin),anchor=south}   , every axis x label/.style={at=(current axis.right of origin),anchor=west}   , height=5cm   , width=12cm   , xtick=\empty   , ytick=\empty   , enlargelimits=false   , clip=false   , axis on top   , grid = major   , hide x axis   , hide y axis   ]    \addplot[cyan!50!black, rotate=-45] (x, {normal(0, 1)});  \end{axis}   \end{tikzpicture}  \end{document}     Any help to get this graph will be highly appreciated. Thanks I recently read that:     What our current level of thermodynamics does tell us though is that if there is such a thing as a Big Crunch, the universe will look a lot different as it heads towards collapse than it did when expanding – the universe started in a state of low entropy and high order and will end in a state of high entropy and   low order.   But shouldn't the order be in a high state and hence entropy becomes a low state in the Big Crunch (assuming a closed universe)?  The reason I write this is because the gravitational forces in a closed universe are so strong they will cause gravitational collapse so the universe will shrink and go backwards, eventually through all the stages of the big bang and become a singularity once more.   It was my understanding that a singularity has a state of high order and low entropy. Have I got this the wrong way round?   If so; Can someone please explain why? Windows file copy dialog: Why is the estimation so... BAD? I know that the Windows copy dialog (in Windows&nbsp;XP) stores the copy in memory first, and it is still copying after the dialog closes, so the time is off, but why is the estimation of the time it will take to make a copy so inaccurate, even when memory copying has been disabled (in Vista and Windows&nbsp;7)? It seems so arbitrary! How does the whole copy procedure work, and why can't Windows estimate it correctly? Given that $a$~$\mathcal{N}(\mu, \Sigma)$ and $\mu$~$\mathcal{N}(0, \sigma^2 I)$, Is $p(a|\Sigma, \sigma)=\int p(a|\mu, \Sigma)p(\mu|\sigma)d\mu$ again a Normal distribution? And how to estimate the mean and variance respectively? Thanks a lot! Ubuntu 14.04, problem when install gstreamer1.0-libav, unmet dependencies Python scope: "UnboundLocalError: local variable 'c' referenced before assignment" I am trying to figure out this:  c = 1 def f(n):     print c + n  def g(n):     c = c + n  f(1) # =&gt; 2 g(1) # =&gt; UnboundLocalError: local variable 'c' referenced before assignment   Thanks! Creating Indexes on DB with Hibernate @Index Annotation JQuery to load Javascript file dynamically Finding $E(|X_1|\ |\max |X_i| )$ Suppose $X_1,\ldots,X_n$ are a random sample of $U(-\theta,\theta)$ with $\theta&gt;0$. How can find $$ E\left(|X_1|\ \big|\max |X_i| \right) $$ that $1\leq i\leq n$? Calling a Java method with no name