Proving that a finite simple group (order < 100) is either abelian or has order 60
$G$ is non abelian simple group of order $<100$ then $G\cong A_5$
I accidentally changed /var owner/group to my username and then changed it back to root, but not all the /var folders' owners are root, so is there anyway to change back owner/group of files/folders to default state?  Or at least those files/folders that are created by packages? Drush from GitHub stopped working I have a  that has been working since it moved there.  I did a git pull this morning, and am now getting errors:     $ drush      Warning: require(/home/mpd/drush/vendor/autoload.php): failed to open   stream: No such file or directory in   /home/mpd/drush/includes/bootstrap.inc on line 1007      Fatal error: require(): Failed opening required   '/home/mpd/drush/vendor/autoload.php' (include_path='.:') in   /home/mpd/drush/includes/bootstrap.inc on line 1007   How can I fix this? A horizontal line with the same space-filling behaviour as /hfill? Is there a command or package which would allow me to draw a line in the largest available space in the way that \hfill fills up the remaining space in a line?  i.e., a command to draw a line from the end of the text, wherever it happens to fall, to the right edge of the textwidth (leaving space for any additional text indented to be at the end of the line)? The novel centers around a man living a comfortable existence in the pretty distant future.  To support himself, he is occasionally asked to enter a box which will copy his entire body, and send it out faster than the speed of light to some developing world, to work.  His copy on this world wakes up and realizes what a big mistake he's made.  The copy does grueling work, feels lonely, and eventually just dies of radiation sickness.  Back on earth, the man never realizes how bad it is out there, and keeps sending out more copies.  I think the story is probably 80s or earlier - not sure if it's a short story, or the beginning of a novel which I lost &amp; never finished. On the nilpotence of the matrix $AB-BA$ Let's say I have code like this:  $dbh = new PDO("blahblah");  $stmt = $dbh-&gt;prepare('SELECT * FROM users where username = :username'); $stmt-&gt;execute( array(':username' =&gt; $_REQUEST['username']) );   The PDO documentation says:     The parameters to prepared statements don't need to be quoted; the driver handles it for you.   Is that truly all I need to do to avoid SQL injections?  Is it really that easy?  You can assume MySQL if it makes a difference.  Also, I'm really only curious about the use of prepared statements against SQL injection.  In this context, I don't care about XSS or other possible vulnerabilities. "No, I didn't see him" vs "Yes, I didn't see him" Bob didn't come to office today.  I was asked "Didn't you see Bob today?"  Should I say "Yes, I didn't see him today" or "No, I didn't see him today"? Sounds simple but I seem to fail every time, that is it turns into scrambled eggs instead. How do you make it so that you can flip it over both without it breaking and before it burns? Why is my camera so forgiving for overblown exposure when shooting in RAW? Using recordtypes of the same name across multiple SObject types I have one recordtype named 'India' in both Account and Contact Objects.My requirement is whenever i create a new account record of type 'India' a new contact record of type 'India' should be created automatically.  i tried with the following code:  trigger AccRecTypeTrigger on Account (before insert) {     List&lt;RecordType&gt; recType = [select id,name from RecordType where sobjectType = 'Account' and isActive = true];    Map&lt;String,Id&gt; m = new Map&lt;String,Id&gt;();    for(RecordType r : recType){      m.put(r.name,r.id);    }     List&lt;Contact&gt; conlst = new List&lt;Contact&gt;();    for(Account a : trigger.new){        a.recordTypeId = m.get('India');        Contact con = new Contact();        con.accountId = a.id;        con.recordTypeId = a.recordTypeId;        con.recordType.name = a.recordType.name;         conlst.add(con);       }    insert conlst; }   But i am getting following error when i try to save     Apex trigger AccRecTypeTrigger caused an unexpected exception, contact   your administrator: AccRecTypeTrigger: execution of BeforeInsert   caused by: System.NullPointerException: Attempt to de-reference a null   object: Trigger.AccRecTypeTrigger: line 14, column 1   Please help me how to achieve this...... Why can I not access a file named `-` when quoting? I have a file called -.  I want to display its contents.  One way is to do  cat ./-   since cat - reads from standard input. However, why are cat "-" and cat '-' also interpreted by the shell as cat -? When I capture packets using the packet analyser wireshark while visiting  I can see packets that use the HTTP protocol (e.g.a GET request). My Get request uses 4 protocols: Ethernet II, IPv4, TCP and HTTP.  For the IPv4 I can see my own local IPv4 address of my pc as the source, for the destination I see the IPv4 address 91.198.174.225. When I go to this address in my browser I get to some wikipedia related website that says'wiki does not exist'. Why am I not seeing the Hydrogen article when I go to that ip address? I have been trying to show these two inequalities hold for all positive integers n, but I don't know how to proceed at all... I have tried playing around with them but I didn't find anything helpful. I have also tried induction but I couldn't make it work. I'm fairly new to bicycling; apologies if this is a standard question but I couldn't figure out how to phrase it to search for it elsewhere.  I ride a KHS Urban-X with Kenda Kwest tires (just what it came with). I've gotten barely any use out of it since owning it, and it's been resting comfortably in the living room through the winter, so I decided today was a great day to get back on.   So I unscrewed the back tire cap, and began to hand-pump air into the tire. All seemed to go well, and the tire held pressure fine, but when I removed the tire pump, the pin appeared to remain pushed down slightly, and air flowed back out of the tire. I looked, and this is what I saw:    Several narrow gashes that appear as if the rubbed was ripped, cut, or separated somehow.  Questions   Is this a common occurrence? Again, I've ridden on this bike very little and thus filled up the tires even less. We have no animals and no bugs around that I know of that would gnaw or chew on such material. Is this fixable, or is my tube completely shot? It would seem to me that the latter is the case. Is there anything I can do to prevent this in the future? I use a hand pump but am gentle; would a stand-up pump be a better choice?  Do bike tires come with a standard warranty for cases like this, or do you know of any brands that do? If I have to purchase new tires, I'm going to purchase Is there any kind of "off-season" maintenance that I should be performing on my bike that could prevent things like this?   Thanks in advance for any help you can give! What is the logical form of the definition of validity? My text book gives the definition of validity as "An argument is valid IFF if the premises are true, then the conclusion must be true". Using a conditional elimination on the RHS of the IFF yields "An argument is valid IFF the premises are false or the conclusion is true".   Yet, this seems strange to me. Am I doing something incorrect with my manipulation or is this definition actually true? Surely the criteria for a valid argument goes beyond a false set of premises or a true conclusion. How can I prove that $\mathbb{Q}[x,y]/\langle x^2+y^2-1 \rangle$ is an integral domain?  Also, I need to prove that its field of fractions is isomorphic to the field of rational functions $\mathbb{Q}(t)$?    (The question is taken from ) Proving if $a$ is not a multiple of prime $p$, then an integer $b$ exists such that $p^b - 1$ is a multiple of $a$ I tried many approaches but none of them really worked I treated $p^b-1$ as a Geometric progression but it didn't work and that is about as far as I have been able to go I have no clue how to move forward Interface vs Base class Is there a criterion to differentiate "thriller" from "horror"? The genres, in my opinion, have a very slim boundary separating one from another. I see a lot of movies being categorized as thriller or horror almost interchangeably, which might seem like lack of thought or criteria. However, is there a true criterion used to differentiate between the two film genres? Adding more than 15 digits in Excel I want to add more than 20 digits in an Excel cell.  The current format of the cell is general, it converts the number to an exponential format. I tried with a number format and accounting, but when I enter more than 15 digits it gets converted to 0's.  What are the recommended steps for stopping Excel from converting data to exponential Format for 20 digits when in the general format?     Example: 12345678901234567890   Excel converts it to 1.23457E+19 in general format.  Without using ' before the value, is there any other way to keep value same?