Proving that $\langle x, y \rangle$ is a not principal ideal of $\mathbb{Q}[x, y]$
Non-principal ideal in $K[x,y]$?
Complex polynomial of degree $n$ AudioSessionSetActive and AudioSessionSetProperty is deprecated in iOS 7 In how many ways can we choose $r$ numbers from $\{1,2,3,...,n\}$,   In a way where we have no consecutive numbers in the set? (like $1,2$) iPhone asks for Mac password (or Mac asks for iOS password) During iPhone update to iOS 10.3.1, I was asked for my password using the correct machine name for my Mac mini. To be clear, the request was not for my iCloud password, my actual local user account password for macOS. This can also happen in the other direction - setting up a Mac may ask for verification for you to enter your iPhone / iPad passcode (and not your iCloud password)  I could not find any information about this kind of access. I was thinking it was security for iCloud and possibly related to two step authorization or two factor authorization. This is the first time I can think of that I entered a desktop password outside of that actual desktop.  I don't have a screen shot but I recall an implication that some files in my Mac are encrypted and need my password. '... need to enter the password for .'   Are there settings I can I control this assuming it's a legitimate part of iCloud setup process or iOS setup process? How do I get rid of this unwanted bar from Eclipse? Number of possible permutations of n1 1's, n2 2's, n3 3's, n4 4's such that no two adjacent elements are same? Given $n_1 $ number of  $1 $'s,  $n_2 $ number of  $2 $'s,  $n_3 $ number of  $3 $'s,  $n_4 $ number of  $4 $'s.  form a sequence using all these numbers such that two adjacent numbers should not be same.  I have tries lot of things but nothing worked.  can somebody tell me how to solve this problem? In C++/CLI, what does the hat character ^ do? I was reading Ivor Horton's Beginning Visual C++ 2008 and many of its CLR examples have this definition for main:  int main(array&lt;System::String ^&gt; ^args)   I went back, page by page, to the beginning of the book to find the first such instance with an explanation what it really means, but couldn't find one.  Obviously it means the same as the standard int main(int argc, char *argv[]), but I'd like to know when and why that ^ is really used, and why it even exists (does it do something that pointers * and references &amp; cannot represent)? In various articles it is mentioned that for secure communications, the recommended key sizes are 128-bit key size for symmetric encryption (which makes it $2^{128}$ possible keys?) and 2048-bit key size for asymmetric encryption ($2^{2048}$ possible keys?).  Why do they differ so greatly? It seems like I am missing a very big part of the equation. Why was Severus Snape placed in Slytherin? How do I increase the size of swapfile without removing it in the terminal? I've been having problems with a blue-screening Laptop (BCCode 124), and I've been trying to track down whats causing it. (It bluescreened randomly after 5-30 minutes of running in win7). It worked in safe mode. I tried reinstalling Windows, which didn't work, so I tried to install various Linux systems which also didn't work.  The only thing working right now is the parted magic version of the ultimate boot cd.(Its a repair linux distro that runs live from ram)  I had the idea to run a bunch of stability tests to try and isolate the faulty component(s), and I wanted some input on my results.  I did different cpu stresstests for different times. No problem (temerature ~60°C sometimes peaks at 65)  I ran memtest with no errors many times.  I also did a GPU check wich is included in the ultimate boot cd - parted magic distro - no problem.  I also checked the hard drive with different tools included in parted magic - no problem there too.  Every linux system I try to install crashes when I try to install it. (It either freezes with no error (rarely happens) or I get something like this shortly after I tell it to install (tried about 20 different distros): [*] 3 photos in the dropbox  Trying to isntall windows 7 just gives a generic "there was a problem" / "an error has occured" screen with no further information.  The laptop is a Lenovo B570. Here are the detailed system specs (the ram is a 4GB kingston now) [*] the hardinfo file in the dropbox  I have 3 crashdumps from Windows wich I can not open. (visual studio says it cant open old crashdump files) [*] 3 dumps in the dropbox  Can you help me to track down the cause?  Edit: im not allowed to post more than 2 links here so here the dropboxfolder with all the things I mentioned:  [*] I'm curious how USB device recognition works in Windows. I imagine it's something like this:   When you plug in a device, it tells Windows "here's my device ID to tell you what I am" Windows looks to see if any drivers have been installed that match that device ID. The driver probably tells Windows what the device should be called - like "BlackBerry Curve" or "Canon Printer" If so, it somehow associates that device with that driver Otherwise, it looks for a matching driver online (if you let it)   Am I right? If so, that still leaves some questions.   When you install drivers, where do they go? Are they files in a folder, or do they get added to the registry? What is Windows doing when it first recognizes the device, thinks, and finally says "your new device is installed and ready to use?" Where does Windows look for missing drivers? Is it in their own database? Do device manufacturers submit drivers to Microsoft for inclusion there?   Can anybody explain how this process really works? Also, do other OSes do this differently? How can I produce a 'ring (or wheel) chart' like that on page 88 of the PGF manual? Create a workflow rule when Lead status is changed from X to Y I want to create a workflow rule which should be triggered when I change the Lead Status value from 'Open: Not Contacted' to 'Open: Working'  Any help with this please? Can the default font be changed? I have been playing with the settings for the text object recently, and every time I add a new text object, I need to change the font to my favorite one. (Eurostile LT ExtendedTwo) Is there any way to change the default font so I do not need to change it every time I add a new text object?   Example: I have realized that to pronounce the plural form of words ending in -th, we have to drop the letter "h". e.g. Months is pronounced /mʌnts/. But I have never seen this point mentioned in any context. I just want to make sure that this rule is correct and can be always applied. An init-script does not get called on shutdown I have set up an init-script to control the state of a VirtualBox VM:  #!/bin/sh #chkconfig: 35 99 5 #description: vTiger virtual machine  ### BEGIN INIT INFO # Provides: vtigervm # Required-Start: $local_fs # Requider-Stop: $stop_fs # Default-Start: 3 5 # Default-Stop: 0 1 2 6 # Short-Description: Manage vTiger virtual machine # Description: Utility to start and stop vTiger virtual machine on VirtualBox ### END INIT INFO  start() {     echo -n "Starting vTiger"     echo     su myuser -c '/usr/bin/VBoxManage startvm "vTiger" --type headless'     echo "Started virtual machine" &gt;&gt; /var/log/messages }  stop() {     echo -n "Shutting vTiger down..."     echo     su myuser-c '/usr/bin/VBoxManage controlvm "vTiger" acpipowerbutton'     while [ ! -z "`su - juhani -c '/usr/bin/VBoxManage list runningvms | grep vTiger'`" ]; do         echo -n "."         sleep 1     done     echo "Done."     echo "Stopped virtual machine" &gt;&gt; /var/log/messages }  status() {     echo -n "Running VMs: "     su myuser -c '/usr/bin/VBoxManage list runningvms'     echo     if [ -z "`su - juhani -c '/usr/bin/VBoxManage list runningvms | grep vTiger'`" ]; then         RETVAL=3         else         RETVAL=0     fi     echo "Queried virtual machine status" &gt;&gt; /var/log/messages }  echo "Called virtual machine management script with: $1" &gt;&gt; /var/log/messages case "$1" in   start)         start    ;;    stop)         stop    ;;    restart|try-restart|condrestart|reload)         stop         start    ;;    status)         status    ;;    *)         echo $"Usage: $0 {start|stop|restart|status}"         exit 1    ;; esac  exit $RETVAL   The system is CentOS 6.5. If I manually run service [start|stop|status] vtigervm, it works as I expect it to. If the VM is running, $? after the service vtigervm status returns 0, and 3 if it is stopped. I installed it with chkconfig and it created among a few others rc5.d/S99vtigervm and rc0.d/K05vtigervm.  The problem  When I start the system it starts the "service", but on shutdown it does not even run the scripts.  grep "virtual machine" /var/log/messages shows:  *[machine starting]* Called virtual machine management script with: start Started virtual machine *[shutdown -h now]* *[machine stopped]*   What I expect:  *[machine starting]* Called virtual machine management script with: start Started virtual machine  *[shutdown -h now]* Called virtual machine management script with: status Queried virtual machine status Called virtual machine management script with: stop Stopped virtual machine *[machine stopped]*   File permissions &amp; etc:  # ls -lah /etc/rc0.d/ lrwxrwxrwx. 1 root root 13 7.2. 17:49 /etc/rc0.d/K05atd -&gt; ../initd.d/atd lrwxrwxrwx. 1 root root 18 9.2. 00:06 /etc/rc0.d/K05vtigervm -&gt; ../initd.d/vtigervm Ubuntu Wifi drivers not working after getting update What happened to the link to the duplicate when a question is closed as a duplicate? Possible Duplicate:          This question:      has been closed as an exact duplicate, but there is no link to the duplicate so we can neither assess whether the closure is valid nor see the explanations in the duplicate question.  It wasn't so long ago that the duplicate links were shown &mdash; is there a policy change (and if so, why?), or is it just a glitch? How do I remove the file suffix and path portion from a path string in Bash? Given a string file path such as /foo/fizzbuzz.bar, how would I use bash to extract just the fizzbuzz portion of said string?