What is the mistake in calculating such a commutator?
What's wrong with this derivation that $i\hbar = 0$?
Sci-Fi book female fighter pilot All I remember about the book is that the protagonist was a human female fighter pilot, she has short hair, not sure if it was blond or auburn and she was involved in making peace with the alien race.  The alien race was invading Earth, but because of her they stopped, surrendered and because of her helped Earth improve its technology. I remember that she melded with something and was starting to sort of think like them and lose a bit of her humanity.  It was set in the not too distant future. I believe I read it in the 90s. I'd like to use a different + symbol in addition to + in math mode, preferably one which is just bolder than the standard one.  I'm currently using \pmb{+} from the amsbsy package, but it's a bit too lean for my taste, and it looks a bit pointy to the ends.   I am aware of \ding{58} from the pifont package, as well as \Plus from bbding, both of which seem to be non-math mode symbols, and look really bad next to math symbols.  Am I missing some other option to produce a bold +, apart from drawing the symbol myself? Calculating $1+\frac13+\frac{1\cdot3}{3\cdot6}+\frac{1\cdot3\cdot5}{3\cdot6\cdot9}+\frac{1\cdot3\cdot5\cdot7}{3\cdot6\cdot9\cdot12}+\dots? $ Beamer item balls go missing while compiling in XeLateX since yesterday's TeXlive update, however, the same code works with pdfLaTeX. Any solution, please. Here is my MWE: \documentclass{beamer}  \setbeamertemplate{itemize item}[ball] \setbeamertemplate{enumerate item}[ball]  \begin{document}  \begin{frame} \frametitle{A tested title} text \begin{enumerate}     \item this is an item \end{enumerate} text3 \begin{itemize}     \item this is an item \end{itemize} \end{frame} \end{document} Does xbox live gold membership stack when I purchase a new one? I currently have an Xbox Live Gold membership that will expire in March 2011. However the price of membership is increasing to $59.99 starting November 1, 2010.   If I buy a 12 month membership now at the current price of $49.99, will the additional 12 months be added on to my existing membership or will I start a new membership which will expire 12 months after I buy it? Which manga chapters correspond to the 2nd season (or "Season 3" on Netflix) of the anime, "Revival of the Commandments"? The 2nd season (labeled as "Season 3" on Netflix) of the anime, Nanatsu no Taizai: Imashime no Fukkatsu (or The Seven Deadly Sins: Revival of The Commandments), has ended.  Which manga chapters correspond to each of the anime episodes? What is the Big-O of a nested loop, where number of iterations in the inner loop is determined by the current iteration of the outer loop? What is the Big-O time complexity of the following nested loops: for (int i = 0; i &lt; N; i++) {     for (int j = i + 1; j &lt; N; j++) {         System.out.println(&quot;i = &quot; + i + &quot; j = &quot; + j);     } }  Would it be O(N^2) still? Workflow for developing add-on/script I'm trying to figure out a good workflow for developing scripts and add-ons in Blender. Here's what I'm currently doing as I try my luck with a PyNode add-on:   Open blender Create a text editor panel Open my script (external text file) Edit my script in a nice external editor Reload the script Save the .blend file Run the script   Now that I can see what my code does, this Blender instance has been modified, so I can't (make changes to my script and) run my script again. So I do this:   Close blender Open blender with the .blend from step 6 and repeat steps 4-7, over and over and over..   Is there a better workflow for this sort of thing? A characterisation of quadratic extensions contained in cyclic extensions of degree 4 Often times I am not interested in the question so much as I am the answer. Unfortunately, the only site option for bookmarking an optimal answer is to bookmark the question. This leaves you having to remember that no the question wasn't that great, but there's an answer in here worth a million. It'd be nice to be able to favorite an answer allowing you to jump immediately to the answer that was much more valuable than the question. I understand that I can bookmark the answers link using my browser but it seems being able to favorite the answer within the site's ecosystem is useful. Why do I have the "required reviews completed" status on my submission in Elsevier? I had submitted my paper in an Elsevier journal one year back. Now, status update on the submission tracking says "Required reviews completed." However, for the last two weeks still there is no change in the status.  Should I ask the editor what is going on with my submission? Hotspot and Internet access together — why not? If I try to set up a hotspot in GNOME, I get the following message:  If you have a connection to the Internet other than wireless, you can use it to share your internet connection with others. Switching on the wireless hotspot will disconnect you from &lt;network name&gt;. It is not possible to access the internet through your wireless while the hotspot is active.  What are the technical reasons why I can't set up an Hotspot and be connected to the Internet at the same time? Show inline math as if it were display math (and vice versa) How can I take shallow depth of field photos with a point-and-shoot camera? Mysql Select some random rows and plus one specific row How to remove old device from Safari iCloud Tabs? I returned a MacBook to Apple Store, however apparently I forgot to sign out of iCloud and the latest tabs I was browsing still appear in Safari iCloud Tabs of my new MacBook and existing iPad.  I removed the device from icloud.com -> Find My iPhone but it didn't work. Tabs list from my old computer is still there and I am trying to remove it from my devices list. I appreciate any ideas. Intersecting transparent object causing artifacts in cycles When two objects -one of them transparent- intersects it creates some artifacts visible even in the alpha channel. Even with 1024 transparent bounces the artifacts remain.    In the example file there are two cubes in the same position, one transparent and one emission.    What is causing this? Any way to get rid of this artifacts? I have a datetime column in MySQL.   How can I convert it to the display as mm/dd/yy H:M (AM/PM) using PHP? Joining multiple records to single feature using QGIS I'm trying to create a join/relate in QGIS where I have a shapefile of buildings and to that I would like to join a non-spatial table (.csv-file) containing people who work in each building. So I have multiple records in my table that I would like to be able to join to my single features in my shapefile. I can only run a join in QGIS where the first record is joined to the shapefile feature (ie building) but subsequent records get removed. Could someone let me know how to complete this join/relate in QGIS? Hint on how to prove the identity $\sum_{0 \leq k \leq n } \binom{k}{m} = \binom{n + 1}{m + 1}$