Asked first in WordPress.SE.com:  Many times, we do Favorite Questions in SE Networks for our future use. But what we got, a list of Titles of Questions in our personal profile. I wonder sometimes I get lost into the very titles &mdash; because some of the titles are not clearly saying what they are, or what they contains, or some of the Answers may contain something "extraordinary" that not just mentioned in the Question label.  So I'm thinking of implementing a "Personal Note" &mdash; whenever we will try to Favorite a Question, a popup &lt;textarea&gt; will appear to contain a limited amount of texts (i.e. 300 characters); and that will be visible beside the Question Labels on the list of Favorite Questions, so that it'd be easy for a user to find out which Questions was favored (?) and why that was favored exactly.  But the Notes will be Optional &mdash; can be skipped on the process of favoring a Question.  So, Can we implement "Personal Notes" to Favorite Questions?
I quite often add a question as a favourite when there is something of interest to me in it or its answers. Looking back through my favourites, I cannot remember why I added some of them as a favourite.  What I'd like to be able to do is to add a note/comment when I add a favourite as a reminder as to why I've added it. This will show on my favourites page, but nowhere else - and possibly to no one else.  In addition, it would be good to be able to favourite an answer to a question, thereby adding a favourite to both the question and a particular answer with something of note in it. This would only show as a single favourite, but when clicking its link would go to the favourited answer.  Possible? Or is there another way of doing this? I've already got too many favourites to remember why I added a lot of them.
Example of a finite non-commutative ring without a unity Give an example of a finite, non-commutative ring, which does not have a unity.    I can't think of any thing which fits this question. I was thinking $M_2(\mathbb{R})$ but it has the identity. Any help is appreciated. If you select "USB" and "Mac" on , it gives a series of command line instructions to make a USB key which the MacBook will boot into Ubuntu from.  I've followed them to the letter two or three times on different USB keys, and it doesn't work. There's a very great deal of technical discussion about EFI etc. but this set of instructions seems to suggest it should just work, but it doesn't.  Help? I'm increasingly unhappy with the more locked-down approach Apple is taking, and I'd quite like to start using Linux with a view to transitioning over to using it as my main operating system, but booting from the CD takes forever, runs slowly and I'm really hoping to get it moving off USB.  Can anybody help me? How to understand the combination formula? I'm reading an algorithm book. In which it mentioned:     Imagine (once again) you have n people lined up to see a movie, but   there are only k places left in  the theater. How many possible   subsets of size k could possibly get in? That’s exactly $C(n,k)$, of   course,  and the metaphor may do some work for us here. We already   know that we have $n!$ possible orderings of  the entire line. What if   we just count all these possibilities and let in the first $k$? The only   problem then is  that we’ve counted the subsets too many times. A   certain group of k friends could stand at the head of  the line in a   lot of the permutations; in fact, we could allow these friends to   stand in any of their $k!$  possible permutations, and the remainder of   the line could stand in any of their $(n–k)!$ possible  permutations   without affecting who’s getting in. Aaaand this gives us the answer!       $$C(n,k)= \frac{n!}{k!(n −k)!}$$      This formula just counts all possible permutations of the line (n!),   and divides by the number of  times we count each “winning subset,” as   explained.   I'm not quite understand why the reminder can in any $(n-k)!$ permutation, if he stands at the end of the queue, won't he let all these people in?  And why I should use $n!$ to divide by $k!(n-k)!$ ? Didn't see that consequence from the metaphor.  If you have better ideas to explain this formula, you can use them of course. I want to attach a code file to my question, but I am not able to find a link to do it. Is attaching files possible at all? MWE for externalize + automatic recompilation after tikz figure modification The ring $\Bbb Z\left [\frac{-1+\sqrt{-19}}{2}\right ]$ is not a Euclidean domain Can an iOS user play with pc users? I have a Mac only, so I am not able to get Terraria through Steam. I was wondering if I can play Terraria on my iPad Mini with a friend who has it on his PC. I was wondering this, because I saw that Deepworld on iOS is compatible with the Mac version. Story about main character with regeneration powers I read a book 10+ years ago where the world was ruled by various factions, each one had a special ability of some sort. The main characters faction had regenerative ability. Another faction had the ability to speed up or slow down time. I am not sure of the plot, but I know at one point he is injured so badly he starts growing a clone which he attempts to kill, but comes back later in the story.    Any ideas? Reset post score to 0 on migration How to Send Html Emails in Google Spreadsheet Here's an example of a Google Docs Spreadsheet script that sends emails using Google spreadsheets. I want the email Sent in HTML not plain text. Can someone help me out?  function sendEmails() {   var sheet = SpreadsheetApp.getActiveSheet();   var startRow = 2;  // First row of data to process   var numRows = 2;   // Number of rows to process   // Fetch the range of cells A2:B3   var dataRange = sheet.getRange(startRow, 1, numRows, 2)   // Fetch values for each row in the Range.   var data = dataRange.getValues();   for (i in data) {     var row = data[i];     var emailAddress = row[0];  // First column     var message = row[1];       // Second column     var subject = "Sending emails from a Spreadsheet";     MailApp.sendEmail(emailAddress, subject, message);   } } Help me understand the proof for Bolzano-Weierstrass Theorem! I have FlexiPage Home_Page_Default.flexipage assigned as Default Home Lightning Page for all profiles in one sandbox. I need to migrate it to another sandbox and assign as Default Home Lightning Page for all profiles in the destination sandbox.   I am able to retrieve and deploy that flexipage but looks like I am not able to assign it automatically as Default Home Lightning Page for all profiles in the destination sandbox using Force.com ANT Migration Tool or changeset.  Is that possible to migrate default home flexi page assignment from one organization to another using ANT Migration Tool or changeset?  If this is possible then how? When an object is moving in a circle, won't the frictional force oppose it's motion? And if the velocity is always tangential to the path, there is no component of it towards the center, so there is no component of friction towards the center (since the frictional force is antiparallel). So how can friction be a centripetal force, like in the case of a car rounding a corner? What does an unprocessed RAW file look like? Shortcut for toggling between different windows of same app? I opened two Google Chrome windows (because I am using multiple Gmails) and when I do the Cmd ⌘ Tab ⇥ shortcut it just shows me other applications that I opened but does not show me the other Chrome windows that are already opened.  How to switch to the other Google Chrome window that I opened using keyboard shortcut? I just got a new hat! :D screaming with joy Looking at so many users looking all exquisite with their stunningly 'fitted' hats, I'm wondering if there's an option to resize or rotate a hat?  PS: Happy Winter Bash everyone! :) I was working on a Beamer presentation, and noticed that, if I open a group scope and use a \tiny, the font size will bet set, but there will be a large space between lines. However, if I issue a \par at the end of the paragraph, it works as intended:  \documentclass[t]{beamer} \newcommand{\shortlipsum} {Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Ut purus elit, vestibulum ut, placerat ac, adipiscing vitae, felis. Curabitur dictum gravida mauris. Nam arcu libero, nonummy eget, consectetuer id, vulputate a, magna. Donec vehicula augue euneque. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Mauris ut leo. Cras viverra}  \begin{document} \begin{frame} \shortlipsum  {\tiny \shortlipsum\par   % &lt;--- removing this \par will break line spacing } \end{frame} \end{document}   Here's a comparison between not using and using \par:    Am I doing it the right way? Why is \par the right way? Which way should arrows point in a collapsible accordion? Left/down … down/up? Prove or disprove: if $\sum\limits_{n=0}^∞a_n$ converges and $\lim\limits_{n\to\infty}b_n =0$, then $\sum\limits_{n=0}^{\infty}a_n b_n$ converges. Mobile phone battery charger I would like to know about the workings of mobile phone battery chargers. I know the basic principle, you take a transformer to bring it down to 9/6/3.7 volts then a bridge rectifier circuit and a capacitor input filter to rectify it into DC. Then you apply it to the battery. But I know this should not be enough, I need at least two things,   Protection against back current flow Switch off power when the battery is fully charged.   Can someone point me to something simple (apart from this )