I was wondering, can a prime number be negative? We had a question over at  which stated that prime generation with openssl:  openssl dhparam -text 1024   results in a 1024-bit number to which leading zeros are added (resulting in 1032 bits). It could be the case that this is done to sign the integer,  however it was my believe that negative primes did not exist?
Do we have negative prime numbers?   $..., -7, -5, -3, -2, ...$
This is, how I download various master branches from GitHub, and I aim to have a prettier script (and maybe more reliable?).  wget -P ~/ https://github.com/user/repository/archive/master.zip unzip ~/master.zip mv ~/*-master ~/dir-name   Can this be shorten to one line somehow, maybe with tar and pipe?  Please address issues of downloading directly to the home directory ~/ and having a certain name for the directory (mv really needed?). The output from uname:  root@debian:~ # uname -a Linux 5asnb 2.6.32-5-amd64 #1 SMP Mon Jun 13 05:49:32 UTC 2011 x86_64 GNU/Linux   However the /sbin/init executable shows up as 32-bit:  root@debian:~ # file /sbin/init /sbin/init: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, stripped   Other aspects of the system seem to contradict things as well:  root@debian:~ # echo $HOSTTYPE i486  root@debian:~ # getconf LONG_BIT 32 Can you catch a native exception in C# code? In C# code can you catch a native exception thrown from deep in some unmanaged library? If so do you need to do anything differently to catch it or does a standard try...catch get it? Open an app on startup/after booting I need to force a selected application to start up each time my Android-based device is (re)started.  Is there anything I can use (configuration setting, external application etc.) to accomplish this task? Or is this kind of behavior limited to home screen managers only? Cleaning my Macbook Pro Retina leaves greasy 'streaks' across the screen Can't use String#trim as a callback for Array#map Need help in proving that $\frac{\sin\theta - \cos\theta + 1}{\sin\theta + \cos\theta - 1} = \frac 1{\sec\theta - \tan\theta}$ We need to prove that $$\dfrac{\sin\theta - \cos\theta + 1}{\sin\theta + \cos\theta - 1} = \frac 1{\sec\theta - \tan\theta}$$  I have tried and it gets confusing. Why has Earth's core not become solid? Light "diode" and 2nd law of thermodynamics If I had a light "diode" - an object that only allowed light (at least for a range of frequencies) to travel through it in one direction, would this necessarily allow violations of the 2nd Law of Thermodynamics?  Or would it be possible to restrict other properties of the device such that it could be okay.  Why I think it should violate 2nd law:   I can place such devices at temperature T in a bath of thermal radiation at temperature T, such that it forms a box which only lets the light in or out.  This would appear to always allow one to create a thermal gradient.  Once a thermal gradient is formed, useful energy can be extracted.  This seems to allow useful energy to always be extracted from a thermal bath and thus give perpetual motion. Release one such device at temperature T in a bath of thermal radiation at temperature T.  Since the photons are absorbed or reflected in one direction, and undisturbed in the other, the device will start moving.  It can use a thermal bath to directly generate useful motion.   Why I think I'm missing something and such a device could potentially co-exist with the 2nd Law:   The above arguments seem valid if the diode was only 'partially' rectifying as well.  However there exist sunglasses which largely reflect on one side, but not from the other side. Researchers have succeeded in using meta-materials to create a "blackhole" for microwaves.   Can anyone help sort this out? How do candles and wicks work? Can I use Gödel numbers to make a proof? How can I make a macOS Mojave bootable USB installer in Windows 10? I have downloaded and saved macOS Mojave installation file from the Mac App Store into my external hard drive. Unfortunately, macOS has crashed on my Mac and now I need to install it again. I have used a software named TransMac to make a installation USB in windows following the steps in the link below:    But the provided USB drive after all these steps doesn't show up in my MacBook pro. Considering that I have saved Install macOS Mojave.app on my external hard drive, and I don't have access to any other Mac computers, How can I fix this issue and build a USB for installing Mojave? I want to know, is there a way to make a tungsten lightbulbs filament withstand a mass amount of thermal shock while still producing a vast amount of heat? Can the Universe be deterministic and still allow free will? Possible Duplicate:             As asked in the title, can a Universe which is deterministic at its fundamental level still allow free will? sorry fresh user. I installed about 9 days ago and had issues with Unity disappearing which took 5 days of headaches to fix. It never did fix, I reinstalled.   I set up Plex (media server) and while the server is running and can be accessed by external network devices, I can't add files. Plex says this is because of permissions. I have gone up and down the forums here and at Plex to get an answer. It seems everyone says   chmod -R 755 /media/My\ Book/Videos   will change permissions to allow the folder "Videos" on my external USB 2.0 NTFS 3TB Western Digital drive (which is mounted and accessible through the file manager) as well as every sub-directory and file contained therein to be accessible to user "Plex".  I have used file manager and as soon as you click to change permissions it changes right back. When I chmod with -c it tells me every file is changed (usually 600) to 755 as I commanded it to do. I did   ls -l   to verify and there is no change. (I also used ls -l to make sure I knew who the owner was and it is me (mvl1014). ls -al gives me the same info.)  I swear to god I tried to sudo it and after smashing my head against this keyboard for basically the entirety of my day, I tried it as root. I was scared shi-less but couldn't come up with anything else. sudo su to root and then chmod -R -c /media/My\ Book/Videos  Same result. -c told me every single file was changed and a check in Unity or in terminal confirmed not a darn thing changed.  Now it seems to me that even if that isn't the thing stopping Plex from working there is still a problem with this command not going through.  12.04LTS -- on gen 1 i7 (2.7 GHz I believe) with 6 GB ram   I've attempted to attach a screenshot but I'm told I need 10 reps to do so, which means I'm copy/pasting too.  Please excuse my obfuscation, but Lorem Ipsum seemed unnecessary. And I tried multiple ways to format this but it looks perfect every way and messed up each time in the preview below. (Ugh, I'm a mess.)  $ chmod -R -c 755 /media/My\ Book/Videos  .....  .....  .....  mode of `/media/My Book/Videos/xxxx/xxxx/xxxx.mkv' changed from 0600 (rw-------) to 0755 (rwxr-xr-x)    ls -al shows:  mvl1014@FX6800:/media/My Book/Videos$ ls -al   total 88  drwx------ 1 mvl1014 mvl1014     0 Aug 28 15:17 .   drwx------ 1 mvl1014 mvl1014 20480 Sep  3 14:29 ..  drwx------ 1 mvl1014 mvl1014  8192 Aug 28 15:18 xxxx drwx------ 1 mvl1014 mvl1014 49152 Aug 16 14:02 xxxx drwx------ 1 mvl1014 mvl1014  8192 Aug 27 21:36 xxxx drwx------ 1 mvl1014 mvl1014  4096 Jul 23 19:09 xxxx   I apologize if this has been asked. I looked through this place plus at all the suggested "Similar Questions". The closet thing I got to an answer , but running the provided code with my own UID didn't work either. Can a university retract a degree for actions taken after the degree is awarded? I've tried to construct examples of rings that match all except one of the properties in the definition of a Dedekind domain. (This is an old number theory qual question from Berkeleys MGSA website).  The only starting point that I can think of would be  $R:=K[X_1,X_2,\ldots]$  for $K$ a field. This is clearly integrally closed as any polynomial relation is contained in $K(X_1,\ldots,X_n)$ for some large enough $n$ and $K[X_1,\ldots,X_n]$ is integrally closed being a UFD.  The problem is then to get rid of enough ideals from this ring $R$, so that its dimension would be 1, but I can't seem to figure out what to do.  Anyone have any other ideas for rings that could work as a starting point? The polynomial ring with an infinite number of variables is pretty much the only example that I know of for how to construct a non-noetherian ring that's still a domain. How many group structures make $S^1$ a topological group? Let $S^1$ be the subspace of $R^2$ given the usual topology. How many group structures make $S^1$ a topological group? Schengen visa refused from German embassy Installing Guest Additions causing problems I am trying to install Guest Additions in VirtualBox with Windows XP host and Ubuntu 12.04 guest. I followed the above steps:  Devices-&gt; Insert Guest Additions CD Image. After that I locate the folder /media/VBoxAdditions4.3.4_91027/ and run sudo ./VBoxLinuxAdditions.run   I want to be able to create shared folders and adjust the resolution of the screen. I achieved to do the first issue, but I couldn't do the second one. I didn't get any message, however it is not possible to change the resolution of the screen and I cannot switch to fullscreen. What am I doing wrong?  I found in the instal log the following message: unknown version of the X Window System. I've tried the solution of the proposed link but I got the following message:  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: virtualbox-guest-x11 : Depends: xorg-video-abi-11                     Depends: xserver-xorg-core (&gt;= 2:1.10.99.901) E: Unable to correct problems, you have held broken packages.   I tried also to install with the command sudo apt-get install virtualbox-guest-dkms but nothing is changing. During the installation of dkms I got the message: Error! Bad return status for module build on kernel 3.13.0-32-generic(i686).