I am trying to use the &amp; symbol in LaTeX.  I have looked at many LaTeX resourses and all of them suggest using \&amp; to solve the problem.  However, when I try to use this, I still get the error "Misplaced alignment tab character &amp;."  Are there any other suggestions?
Possible Duplicate:             In the itemize environment, how do I use the ampersand symbol &amp; without LaTeX trying to use it as a command?
I have an iMac, connected to the Internet via Ethernet, and an iPhone 4. I would like to share the iMac's Internet connection to my iPhone via the USB Cable (because my wife dreams of a wifi-less household).  I've set up Internet Sharing, specifying "sharing from: Ethernet  via: USB IPhone", but when I test, the iPhone cannot connect to the Internet. Is there something I need to activate on the iPhone?   iMac, mac os x version: Mountain Lion, 10.8.4 iPhone 4, IOS Version: 6.1 Modular arithmetic: division, fractions, solving linear congruences I've been having this issue for a while where I come to open the Terminal and I'm met with this:  Login incorrect login: _   I've already deleted the com.apple.terminal.plist to no avail. The really interesting thing is that sometimes it works, maybe 1 in 50 times. I literally have no idea what might be causing it and after searching the web for the better part of half a day it seems everyone else's issues are fixed when they delete the plist file.  How do I sort this out? I've tried running different shells (bash and zsh), but I still get this log in screen.  Also when I use Activity Monitor, I can see there is no shell running just the login. Is the latest version of Ubuntu 100% FREE Using 3rd party Python modules According to some grammars[1][2] and CMS...  "Interjections and vocative should be separated from the rest of the sentence by commas".  The vocative case [1] is used to indicate direct address (i.e., to show when you are talking to somebody or something directly). Nouns in the vocative case are set off using commas. CMS 6.38  As direct address (i.e. vocative case), the parenthetical element should be set off using commas (CMS 6.30). An absolute phrase is always treated as a parenthetical element, as is an interjection.  So,      Hello, world!   That is a very classical way to hello the world.  But, languages change. I am not sure, but today, I feel that it is very uncommon helloing someone with an interjection, providing a small pause and clarifying who is helloed. I have an impression that usually people use hello as a ("kind of") verb, not an interjection.   Question: Is that just a personal (bad) impression or some linguistic has already studied that phenomenon?     [1] - Nelson, Gerald C., Director Survey of English Usage Sidney Greenbaum, and Sidney Greenbaum. An Introduction to English Grammar. Routledge, 2013. [2] - Advanced Grammar in Use with Answers: A Self-Study Reference and Practice Book for Advanced Learners of English. 3 edition. Cambridge University Press, 2013. CMS - Chicago Manual of Style Space faring human race encounters one highly advanced spaceship.  The one ship tells the human space fleet to go away and leave them alone. We don't listen and our ships are destroyed.  Human spy is sent to the alien world. Aliens look virtually identical to humans except they have no cartilage in their nose and the 'females' are only capable of mating every seven years. The human spy tells this story and is a brilliant tactician. He enters into a game tournament where they play a very complicated version of chess.  Human spy interacts with a higher ranking military officer who has a human female wife.  Human spy gets caught and when he is ultimately returned to Earth he advises humanity to unconditionally surrender to the alien race.  Humans eventually win because the alien males take human wives and their alien DNA is diluted in the vast human gene pool.  Looking for the title and author if anyone can recall them.  06/15 - update  I found the anthology. 'Second Game' was in 'The Arbor House Treasury of Great Science Fiction Short Novels' which came out in 1980 and 1981.  I did read the original story from 1958 which was actually a nominee for the Hugo Award for Novelette in 1959. Suddenly my Ubuntu stopped playing video. When I open a video, the player suggests that I install  gstreamer1.0-libav. However, it fails to install.  I tried installing it manually, here is the error message:  $ sudo apt-get install gstreamer1.0-libav Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  gstreamer1.0-libav : Depends: libavcodec54 (&gt;= 6:9.1-1) but it is not going to be installed or                                libavcodec-extra-54 (&gt;= 6:9.13) but it is not going to be installed                       Depends: libavformat54 (&gt;= 6:9.1-1) but it is not going to be installed E: Unable to correct problems, you have held broken packages. TikZ: Intersection of two lines what is the easiest way to determine the intersection of two lines? I tried  \usetikzlibrary{intersections} \begin{tikzpicture}[every node/.style={black,above right}] \draw[name path=line 1] (0,0) -- (2,2); \draw[name path=line 2] (2,0) -- (0,2); \fill[red,name intersections={of=line 1 and line 2}]     (intersection-1) circle (2pt) node {1}     (intersection-2) circle (2pt) node {2} \end{tikzpicture} I have understood how ridge regression shrinks coefficients towards zero geometrically. Moreover I know how to prove that in the special "Orthonormal Case," but I am confused how that works in the general case via "Spectral decomposition." Comparing and contrasting, p-values, significance levels and type I error I was wondering if anybody could give a concise rundown as to the definitions and uses of p-values, significance level and type I error.  I understand that p-values are defined as "the probability of obtaining a test statistic at least as extreme as the one we actually observed", while a significance level is just an arbitrary cutoff value to gauge if the p-value is significant or not. Type I error is the error of rejected a null hypothesis that was true. However, I am unsure regarding the difference between significance level and the type I error, are they not the same concept?  For example, assume a very simple experiment where I flip a coin 1000 times and count the number of times it lands on 'heads'. My null hypothesis, H0, is that heads = 500 (unbiased coin). I then set my significance level at alpha = 0.05.  I flip the coin 1000 times and then I calculate the p-value, if the p-value is > 0.05 then I fail to reject the null hypothesis and if the p-value is &lt; 0.05 then I reject the null hypothesis.  Now if I did this experiment repeatedly, each time calculating the p-value and either rejecting or failing to reject the null hypothesis and keeping a count of how many I rejected/failed to reject, then I would end up rejecting 5% of null hypotheses which were in actuality true, is that correct? This is the definition of type I error. Therefore, the significance level in Fisher significance testing is essentially the type I error from Neyman-Pearson hypothesis testing if you performed repeated experiments.  Now as for p-values, if I had gotten a p-value of 0.06 from my last experiment and I did multiple experiments and counted all the ones that I got a p-value from 0 to 0.06, then would I also not have a 6% chance of rejecting a true null hypothesis? How could I write my name, for example, to look like the \LaTeX logo? How could I write my name, for example, in a \LaTeX style? It is just interesting, as in Google all other things pop up when I try to search for an answer! Is it possible to convert virtual machines to physical environments? Is it acceptable to begin a declarative sentence with "Am"? I want to know firstly if it's grammatically correct to start a declarative sentence with "Am". For example:     Am excited about the game today.   Secondly, if it is grammatically incorrect, then I wanted to ask how much "head room" there is for the above usage. I can't think of an example now, nor find one here at english.stackexchange. However I imagine there are usages of the english language that grammatically are illegal, yet have somehow become accepted as colloquial or idiomatic perhaps. I have some files/directories on an external hard drive connected using USB to my Windows XP laptop. I am trying to delete those files but every time I try, I get an error "Cannot delete ....: Access Denied. Make sure disk is not full or write protected and that the file is not currently in use".  I checked that the directory is not is use. However, the permissions are set to read-only. Even if I remove the "read-only" checkbox, in Properties->Attributes, it automatically comes back again. How do I fix this? Is it a virus that is automatically changing it back to read-only?  regards,  JP Where and why do I have to put the "template" and "typename" keywords? In templates, where and why do I have to put typename and template on dependent names? What exactly are dependent names anyway?    I have the following code:  template &lt;typename T, typename Tail&gt; // Tail will be a UnionNode too. struct UnionNode : public Tail {     // ...     template&lt;typename U&gt; struct inUnion {         // Q: where to add typename/template here?         typedef Tail::inUnion&lt;U&gt; dummy;      };     template&lt; &gt; struct inUnion&lt;T&gt; {     }; }; template &lt;typename T&gt; // For the last node Tn. struct UnionNode&lt;T, void&gt; {     // ...     template&lt;typename U&gt; struct inUnion {         char fail[ -2 + (sizeof(U)%2) ]; // Cannot be instantiated for any U     };     template&lt; &gt; struct inUnion&lt;T&gt; {     }; };   The problem I have is in the typedef Tail::inUnion&lt;U&gt; dummy line. I'm fairly certain that inUnion is a dependent name, and VC++ is quite right in choking on it. I also know that I should be able to add template somewhere to tell the compiler that inUnion is a template-id. But where exactly? And should it then assume that inUnion is a class template, i.e. inUnion&lt;U&gt; names a type and not a function? I've seen this message several times whenever someone has a problem installing, upgrading or removing some piece of software, but I wonder, what does it mean, and more importantly, is possible to solve it?  (Reading database ... 81657 files and directories currently installed.)  Removing mongodb-10gen ...  arg: remove  invoke-rc.d: unknown initscript, /etc/init.d/mongodb not found.  dpkg: error processing mongodb-10gen (--remove):   subprocess installed pre-removal script returned error exit status 100  invoke-rc.d: unknown initscript, /etc/init.d/mongodb not found.  dpkg: error while cleaning up:   subprocess installed post-installation script returned error exit status 100  Errors were encountered while processing:   mongodb-10gen  E: Sub-process /usr/bin/dpkg returned an error code (1)   (the above is just an example, not my actual problem) How do I store binary data in ? I've made some high resolution pixel art in PS by drawing it down at the pixel level and then increasing the image size with the nearest neighbor setting to keep it crisp. In the web browser, however, I need to display these images as icons with a dynamic size, so I can't just size the images correctly to begin with, and the broswer seems to blur the images when rendering them smaller, while vector images seem to stay more crisp as they shrink.   So I'm wondering if there's a way to convert the pixel art neatly into vector. I'm aware of the trace function in illustrator, but it seems to do a rough job iirc. What is the meaning of $\exp(\,\cdot\,)$? What is the meaning of the notation $\exp(\text{expression})$ ?  I think that it's something of the form $a^\text{expression}$ but does it mean that the base $a=e$ or can it be any base?