As of December 2017, the largest known prime number was the Mersenne prime $2^{77232917} – 1$.  For such a large Mersenne prime, what are the techniques available for one to verify that it is in fact a prime?  Is it simply a matter of brute force checking, or are there other more elegant techniques available?
I am a software engineer but try to keep up with maths as I really enjoyed the subject at school. I just saw a great TED talk:   The talk states that the current largest known prime is $2^{57885161}-1$  This got me thinking - how does one actually prove whether a number this large is prime or not?  Is it just done by brute force via a computer algorithm or are there any well known mathematical techniques for doing so?  I would be really grateful for any pointers as I am eager to learn about these techniques (if they exist).
I have a module with a page callback handler for the path "products". So if the user navigates to products/apples then the module presents a page about our apples, and if they go to products/oranges then etc. These pages include detail about the various products.  I would like XML Sitemap to be populated from my module. After all, it's my module that knows what products exist, their descriptions etc.  Any hook or anything I can use for that? Addons: Only some .zips will install Why is it that if I go to install an add-on from User Preferences > Add-ons > Install from File... and choose a *.ZIP, some add-ons will install, while others will return me to the User Preferences with nothing having happened (as far as I can tell)?  Is there a specific file structure required in the .ZIP? I get many add-ons from GitHub, using the Download Zip button, and even there installation of the actual Zip file only works some of the time. In most fiction I've read or encountered, the change occurs as a simple consequence of the lunar cycle. Though from what I know of Harry Potter, the change that takes place is due to sighting the full moon (as occurs in the third movie, Prisoner of Azkaban) where the gang, plus Lupin, Severus, Sirius and Pettigrew emerge from the Whomping Willow and upon sighting the full moon he begins to change.  Is this the trigger for werewolves in the Potterverse? If not, why did he (Lupin as an example, though for any werewolf in general) not change whilst in the shrieking shack that night?  Edit: This  addresses Lupin's change but I'm after more general information about werewolves. When compiling a beamer presentation and using the following \author command  \author{Name \\ \texttt{my.email@domain.com}}   I get the following hyperref warning in my logfile  Package hyperref Warning: Token not allowed in a PDF string (PDFDocEncoding): (hyperref)                removing `\\' on input line 15.   Package hyperref Warning: Token not allowed in a PDF string (PDFDocEncoding): (hyperref)                removing `\new@ifnextchar' on input line 15.   I understand that this has to do with hyperref setting the PDF metadata, where the linebreak does’t make much sense and should be removed.  Trying to set  \hypersetup{pdfauthor={Name}}   does’t change the situation, seems like hyperref is still looking at the author command.  How do I get the desired display of author name with email and still keep hyperref happy? Apply function conditionally When should I use mmap for file access? POSIX environments provide at least two ways of accessing files.  There's the standard system calls open(), read(), write(), and friends, but there's also the option of using mmap() to map the file into virtual memory.  When is it preferable to use one over the other?  What're their individual advantages that merit including two interfaces? Chrome is unable to connect to the Internet I'm getting the error code: DNS_PROBE_FINISHED_NO_INTERNET in Google Chrome. The thing is, I have a working internet connection. I am posting this using that connection, using Internet Explorer. It's only Chrome doing this.  What happened was my laptop was refusing to go to sleep mode, so it ended up running out of battery power. I charged it, and when I subsequently booted the computer, Chrome stopped working. I don't see the connection...  I added Firewall rules (inbound/outbound) to allow Chrome to connect...so unless I'm missing something.  UPDATE: Chrome portable is working for me...just not the regular chrome.  UPDATE 2 Now I realize it had to do with Covenant Eyes which I have installed. See the accepted answer Salesforce, Oracle and the Seven Dwarfs Over my time as a Salesforce developer, I've written some code which on occasion managed to surface Oracle plsql exceptions and curiously the error text contains the name of one of Disney's .  I've teased out Doc, Grumpy, Happy, Bashful and Sneezy. I'm sure the other two are not far away.   What is the underlying "thing" on the database platform that is named after a Dwarf? Why were these named after Dwarves?      java.sql.SQLException: ORA-30006: resource busy; acquire with WAIT   timeout expiredORA-06512: at "DOC.CAPEX", line 2200ORA-06512: at line   1: SQLException while executing plsql statement: {call   cApex.update_sysmodstamp(?)}([       java.sql.SQLException: ORA-30006: resource busy; acquire with WAIT   timeout expiredORA-06512: at "GRUMPY.CAPEX", line 2563ORA-06512: at   line 1: SQLException while executing plsql statement: {call   cApex.update_sysmodstamp(?)}([       java.sql.SQLException: ORA-30006: resource busy; acquire with WAIT   timeout expiredORA-06512: at "HAPPY.CAPEX", line 2715ORA-06512: at   line 1: SQLException while executing plsql statement: {call   cApex.update_sysmodstamp(?)}([       java.sql.SQLException: ORA-30006: resource busy; acquire with WAIT   timeout expiredORA-06512: at "BASHFUL.CAPEX", line 2715ORA-06512: at   line 1: SQLException while executing plsql statement: {call   cApex.update_sysmodstamp(?)}([       java.sql.SQLException: ORA-30006: resource busy; acquire with WAIT   timeout expiredORA-06512: at "SNEEZY.CAPEX", line 2718ORA-06512: at   line 1: SQLException while executing plsql statement: {call   cApex.invalidate_agc(?,?)}([      Error: ORA-20000: ORA-06512: at "SNEEZY.SIMPORTLOOKUP", line 850   ORA-06512: at "SNEEZY.SIMPORTLOOKUP", line 823 ORA-06512: at line 1 :   SQLException while executing plsql statement: {call   sImportLookup.get_by_ext_id_text(?,?,?,?,?,?,?)}([ Is it possible to edit the Audit fields on UPDATE? What's the meaning "them" here? I've confused about the word "them" in the middle of the sentence:     They know all about them   Westovers in Idaho.   Could you please tell me what the meaning of "them" here is?     Does it mean "they know about the oils which are made by Westovers in Idaho"?   The full text is here:      Dad had always said he wanted to build a room the size of a cruise ship   but I’d never thought he’d have the money. I looked to Mother for an   explanation but it was Dad who answered. The business was a roaring   success, he explained. Essential oils were popular, and Mother had the best   on the market. “Our oils are so good,” he said, “we’ve started eating into the   profits of the large corporate producers. They know all about them   Westovers in Idaho.”   Educated by Tara Westover How do I pre-install Ubuntu for someone (OEM install)? I have never found experimental evidence that measuring one entangled particle causes the state of the other entangled particle to change, rather than just being revealed.  Using the spin up spin down example we know that one of the particles will be spin up and the other spin down, so when we measure one and find it is spin up we know the other is spin down. Is there any situation after creation that the particle with spin up will change to spin down? home socket with DC voltage I'm wondering why, in a standard house, instead of using many low power AC-DC rectifier, there isn't a big (like 12V 20~50A) AC-DC rectifier which supplies some wall socket with a DC voltage? In the long run this should be less expensive, given the fact that AC to DC in one big apparatus is done better than in many low-quality transformers, right?  Also, modern chip DC voltage regulators have efficiency of >90%, so smaller (or even larger) voltages are still efficient and possible.  So we could use a 12V socket to charge a phone, desktop computer, laptop, radio etc... and still have an AC socket to move washing machine engine and other things that work better with an AC supply.  Why isn't this done?  edit: real question is: is it convenient, given a standard family (2 laptop, 1 desktop, 4 smarthpone, 1 big tv and some minor electonic) to do so? How to *disable* automatic reboots in Windows 10? Windows 10 lets you 'schedule' a reboot for later. I want to disable it.  Evidently Windows scheduled itself for a reboot last night when I wasn't looking and just closed everything I had been working on the night before.  I reboot on the regular; I don't need Windows to do that for me.  Can I disable it completely? I don't mind if it downloads everything, and then says "hey, you should reboot," but it should never reboot itself, ever.  I'm using the "Pro" edition of Windows 10. Is there any app for Stack Exchange? Is there any app available in the Android Market for Stack Exchange sites? How to disable "time travel" entirely? Every time I open a question I get this oh so funny 90s feel with scrollers and whatnots. In every question I need to click it off. The button seems to only work for the specific page I load; loading a different page shows the theme again.  Is this an attempt to keep people from using the site for a few days or how do I tell you "please never ever do anything like this if you want me to keep contributing here"? Yes I have no sense of humor if this is an attempt at that.  How do I turn off "time travel" (also known as "back to the future") mode off permanently, on all questions, and preferably network-wide? I am asking this question from an educational/hacking point of view, (I wouldn't really want to code like this).  Is it possible to implement a while loop only using C preprocessor directives. I understand that macros cannot be expanded recursively, so how would this be accomplished? Is there a way to delete all stack exchange accounts at the same time?  I also want to remove all traces of my posts on the site. Is that possible?   Will I have to delete all of my posts manually?  Can I use the stack exchange API for this? Why is filling a balloon from your mouth much harder initially? Why is it that when you first fill up a balloon, it's hard to get air through, but after inflating it a bit, it becomes much easier to further inflate the balloon? Usage and example of the word “litotes” I've come across the word litotes, which means a rhetorical understatement. However, I’m having trouble understanding how to use it in colloquial English. Could someone please give an example?