Posts by a user to a specific site
Viewing all my questions from Android app
I have a basic doubt about the associativity of the cartesian product. Well, first wikipedia says that the cartesian product isn't associative, and there's a good argument for it: if $x\in E$, $y\in F$ and $z \in G$ the identity $((x,y), z)=(x,(y,z))$ would imply that $(x,y) =x$ and $(y,z) = z$ so that $((x,y),z)=(x,y,z)$ would mean nothing.  That's fine, I like this argument. However, in his book Calculus on Manifolds, Spivak says that the cartesian product is associative. He says: if $A \subset \mathbb{R}^m$, $B\subset \mathbb{R}^n$ and $C \subset \mathbb{R}^p$ then $(A\times B)\times C = A \times (B \times C)$, and both of these are denoted simply by $A \times B \times C$.  Well, this confuses me because Spivak is always very rigorous, so that he wouldn't state something that's not true in such way. Is Spivak or Wikipedia right ? Or Spivak's statement only works for subsets of euclidean spaces ?  Thanks in advance and sorry if this question is too basic. How do you use the CSS content property to add HTML entities?  Using something like this just prints &amp;nbsp; to the screen instead of the non-breaking space:  .breadcrumbs a:before {     content: '&amp;nbsp;'; } For you that have tested this, should we use Ubuntu and install different Desktop Environments (KDE/XFCE...) or we should install different distributions (Kubuntu/Xubuntu...). Are there any notable issues in performance / CPU consumption?  PS:  I know how to install them (already did), I wanted to know if anyone has any problems regarding the performance and what is better to install the desktop or to use the ditribution How do we know the Taylor expansion for $e^x$ works for all $x$? Or that it's analytic? How do I share a private YouTube video with someone? I have uploaded a YouTube video and marked it as private.  Now I want to share it with someone. I have tried to share it a few times, but they have not received any email notification.  What is the proper way of sharing the video? Can we continue to show the "Take a tour" banner after a user has created an account? Google crawlers screen size Imagine a I have two types of images (A and AAA(heavier)) for the same website: depending on the size of the screen it will show one image or other.   Now I'm wondering what images (A or AAA) loads the Google crawler when it visits my site.   In other words: has the Google crawlers any "screen size"?  I suppose, in case the it loads the A images, the page-speed puntuation will be better than if it loads the images AAA. I'm currently using the below script to timestamp when an edit is made to column 7 on a sheet named "Sheet 1".  function onEdit(e) {    if ([7].indexOf(e.range.columnStart) != -1) {    e.range.offset(0, 7).setValue(new Date()).setNumberFormat("dd.MM.yyyy at HH:mm");    }   }     I have a second sheet "Sheet 2" which I need to run the same script on but against column 5.  function onEdit(e) {    if ([5].indexOf(e.range.columnStart) != -1) {    e.range.offset(0, 7).setValue(new Date()).setNumberFormat("dd.MM.yyyy at HH:mm");    }   }     I've tried .getSheetByName("Sheet1") but just cant seem to get it working correctly. VMware won't work after Ubuntu Upgrade I upgraded to Ubuntu 15.10 and now if I want to open VMware Player it doesn't do anything. I also uninstalled and installed it again, still nothing.  What can I do? Date comparison : which date format? Why does C++ have header files and .cpp files? Desperate to locate and re-read exceptional book/series, but cannot remember the title. The high concept: The U.S. has just sent the first successful expedition to Mars, and it has just landed. As the astronauts make their initial exploration outside their ship, a tear in the fabric of space opens up right in front of them, and they look through to the insides of a laboratory (at a California university?) and two students who just figured out how to create arbitrary portals between two points in the Universe. The rest of the novel/series is a consequence of this breakthrough. But I can't remember the author and title(s). Surely someone reading this forum will remember it well! TIA.  (Reposted .) How can I acknowledge, thank, or otherwise approve of an edit? Possible Duplicate:    Sometimes I get an edit that greatly improves a question or answer I have submitted.  I'd like to acknowledge an edit like this, so that readers can know that the revision was approved of by the OP (me!). I was thinking of comments on edit, or a checkbox noting that OP vouches for the edit.  Sometimes I would like to add a comment to the question or answer, but those don't make a lot of sense in that context. Any suggestions about the best way to do this?  Consider this a feature request, as it seems useful to know that a particular edit was endorsed/vetted by the OP. I want to install selenium webdriver in my Ubuntu 16.04 system for python How do I straighten UV maps? When trying to SSH into a particular Mac machine it gives me the following error :  ssh_exchange_identification: Connection closed by remote host   I have done some google searches on the issue but I haven't seem to find a definite answer. I did notice that on the machine that I am trying to SSH into, it does not have the ~/.ssh file even on there so I went ahead and created it and gave it correct permissions but that didn't help. Here is the verbose of when attempting to SSH into it:  penSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011 debug1: Reading configuration data /etc/ssh_config debug1: /etc/ssh_config line 20: Applying options for * debug1: Connecting to &lt;ComputerName&gt; [xxx.xxx.xxx.xxx] port 22. debug1: Connection established. debug1: identity file /Users/&lt;UserName&gt;/.ssh/id_rsa type 1 debug1: identity file /Users/&lt;UserName&gt;/.ssh/id_rsa-cert type -1 debug1: identity file /Users/&lt;UserName&gt;/.ssh/id_dsa type -1 debug1: identity file /Users/&lt;UserName&gt;/.ssh/id_dsa-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_6.2 ssh_exchange_identification: Connection closed by remote host   Any ideas on how to get SSH working? Is it OK to borrow a ground wire from a different circuit? I've got a circuit in the basement carrying a handful of outlets.  This circuit has no ground wire.  I want to add a couple of outlets and want them to be grounded.  I may even want gfci outlets on them in the future.  I have no reasonable way of getting a ground wire to the panel but I do have easy access to another circuit that does have a ground wire.  Is it acceptable to borrow or share a ground wire between circuits?  If not, why not?  Both circuits are 20A with 12 AWG wire. Creating lots of random cuts on a surface Here's an image of a cube with lots of edges added. It was created using knife tool and lots of clicking:    What would be the best way to randomly generate such cuts with less effort...? JavaScript raises SyntaxError with data rendered in Jinja template Render not showing UV texture