I can't understand a question I came across in a course.     You observe three ciphertexts all resulting from encryption of ASCII   plaintexts containing English letters and spaces only, using the   one-time pad and the same key. The 10th byte of the first ciphertext   is 0xA8, the 10th byte of the second ciphertext is 0xED, and the 10th   byte of the third ciphertext is 0xBD. What is the 10th ASCII character   of the third plaintext?   I XORed 0xA8 and 0xBD and got 00010101 I XORed 0xED and OxBD and got 01010000 so clearly 0xED is a space and 0xBD is a character.  What I don't understand is why it is the letter 'p'.  Thank you in advance.

I've already sent my correct solution to :  "Let us see what goes wrong when a stream cipher key is used more than once. Below are eleven hex-encoded ciphertexts that are the result of encrypting eleven plaintexts with a stream cipher, all with the same stream cipher key. Your goal is to decrypt the last ciphertext, and submit the secret message within it as solution. Hint: XOR the ciphertexts together, and consider what happens when a space is XORed with a character in [a-zA-Z]."  I managed to get the key by XORing ciphertexts #1 and #2, then XORing the result with the string " the " at each possible position.  Combined with a lot of guesswork, this gave me the first plaintext. My question is: What would I have to do if I want to follow the hint? I know that if I XOR a space with a letter, I change the case of the letter, but then what? I don't understand how I can recognize spaces!  Suppose I see a letter in $c_1 \oplus c_2$; how can I tell if there was a space in one of the plaintexts?


In DB i have only one table: navigation (InnoDB)   Is it possible configure this table to: If i delete where id == 1, all id 1 (Root Item) subs will be deleted automatically?  UPDATE  I try to recreate table:  CREATE TABLE `navigation` ( `id` int(10) unsigned NOT NULL auto_increment, `name` VARCHAR(32), `url` VARCHAR(32), `position` int(10), `parent_id` int(10) unsigned NOT NULL, PRIMARY KEY (`id`), KEY `type` (`parent_id`) CONSTRAINT `??????` FOREIGN KEY (`parent_id`)   REFERENCES `types` (`id`) ON DELETE CASCADE ON UPDATE CASCADE )   But What value need in line 9?

I have a database of components. Each component is of a specific type. That means there is a many-to-one relationship between a component and a type. When I delete a type, I would like to delete all the components which has a foreign key of that type. But if I'm not mistaken, cascade delete will delete the type when the component is deleted. Is there any way to do what I described?


I have the following question:  Prove of give a counterexample: Suppose that $f$ is holomorphic on $\mathbb{D}$ and continuous on its closure. Then, $f$ extends to a analytic map on $B_{(0,R)}$ for some $R > 1$.  I am really not sure whether the statement is true. I can't think of any functions that are analytic in $\mathbb{D}$ but not on the boundary, so it seems like the claim might be true. But, I do not know how to define the function outside of $\mathbb{D}$.

Let $\mathbb{D}=\{z \in \mathbb{C} \ | \ |z|<1 \} $ be the open unit disk in the complex plane. I would like to see explicit examples of the following phenomena:   a holomorphic function $f$ on $\mathbb{D}$ which extends continuously to the boundary but has no holomorphic extension beyond any boundary point (i.e. on sets of the form $\mathbb{D} \cup B(z_0,r)$ for some $r>0$ and $z_0 \in \partial \mathbb{D}$) a holomorphic function $f$ on $\mathbb{D}$ which is bounded on $\mathbb{D}$ but has no holomorphic extension beyond any boundary point (i.e. on sets of the form $\mathbb{D} \cup B(z_0,r)$ for some $r>0$ and $z_0 \in \partial \mathbb{D}$)   Such functions should exist according to this  to a previous . Thanks for any reference/advice.


So I wanted to hide the Finder icon on my Dock.  According to this answer -  I am suppose to edit DockMenus.plist file. When I tried I had no permission to do that. I tried to use chmod (also with sudo) on that file with no effect, same message from terminal - Unable to change file mode on DockMenus.plist: Operation not permitted. I ran ls -lOe on that file and I learned that apparently there is new permission flag called restricted.  I still don't know how to get permission to edit that file. Does anyone have any solution?

Apple has introduced , also known as "rootless", with OS X 10.11, El Capitan. I understand this is a step for general protection against malware but as a developer I need write access to some of the files it locks away.  How do I disable this protection?


I would like to find a wireless adapter for enabling ad hoc or AP mode on Ubuntu that works "out of box".  I have tried edimax 7811Un without success and would like to find another adapter that will work without giving me any trouble.  Can someone recommend an adapter that they have had success with?

I am a bit financially strapped and received a Gateway GT5056 tower. The tower has an AMD dual core 64-bit processor in it. Will Ubuntu 12.04 run on this machine? I will not have any other application other than LibreOffice installed.


I have the following problem:   Given two independent standard normal random variables, call them $X$ and $Y$, how can I show that $Z = X^2 + Y^2$ and $W=\frac{X}{Y}$ are also independent?  I know that because $X$ and $Y$ are standard normal I can write their distributions as $$f_X(x) = \frac{1}{2\pi}e^\frac{-(x)^2}{2}$$ $$f_Y(y) = \frac{1}{2\pi}e^\frac{-(y)^2}{2}$$ Then because they are independent I can write their joint probability distribution as $$f_{X,Y}(x,y) = \frac{1}{2\pi}e^\frac{-(x^+y^2)}{2}$$  Now I know that to show $Z$ and $W$ are independent, I need to show that their joint probability distribution is equal to the product of the marginal distribution functions. But I'm not sure how to find  $f_{Z,W}(z,w)$, $f_Z(z)$ and $f_W(w)$.   Any help is much appreciated.

If $X$ and $Y$ are independent, then $X^2+Y^2$ and $X/Y$ are independent? I was solving the problem for the case that $X$ and $Y$ are independent $N(0,\sigma^2)$.  So i found that $X^2+Y^2$ is negative exponential, $X/Y$ is Cauchy distribution. How can i prove that $X^2+Y^2$ and $X/Y$ are independent?  Also, what it will be if the case for general random variable $X$, $Y$ with  $X^2+Y^2$ and $X/Y$ are defined?


I have already clicked on the acceptance of an admit(without funding). The deadline for response is Apr.15th, and I did not have any other options at that time. However, I just received a funding offer from a top University. I am wondering if I could reject the accepted admit. If yes, how to reject it very very politely? Will this affect credibility?

I have accepted a PhD offer from a very good university to do a project very close to my interests. I have told the project supervisor I accept it. In the meanwhile I have managed to secure a PhD offer from another 2 universities much better in world rankings and with better research groups and better faculty. Additionally these 2 universities do research exactly on what I want to devote my PhD research.  My only commitment to the first university is a mail confirming I accept. Nothing else. I understand declining the offer after already having accepted it is quite dishonest but it is a huge decision that will affect my future in a very significant level.   I would like your opinion and I would also like to ask for possible consequences of such an action. As far a postdocs concerned, in the first university there is no chance I ever get a postdoc since they do not actually do research on my area (except for the prospective supervisor and even he not as much).  UPDATE I have decided to do as I was afraid to. I have decided to choose a different university than the first one that I have already accepted the offer. My offer acceptance included:    An online "I accept" statement. An e-mail I sent stating "I accept the scholarship and this University is my first option"   I do not have any legal commitments since I have not signed anything. The supervisor of the first university though is really nice to me and continuously was sending me mails. How do I very nicely tell her I will not be joining in the end? Additionally the place I will go in the end will be for research in Mathematics and not Physics. Can I use this as a part of a sensical excuse?  WHAT I HAVE CHOSEN AND WHAT THE CONSEQUENCES WERE  I think that I should let people, especially other beginning grad students know what happened with my case. I have chosen to nicely tell the first university I got accepted that I will not be attending and will not be pursuing a PhD there since I decided I have different research interests (which is true). I had applied there in the first place since I was not sure what I wanted to do and because it was a nice program. Despite that, I got an offer from a World top university to work on 100% my research interests. I explained this to them, the first uni, and they happily let me go and wished me good luck, especially the supervisor who faught a lot secure me funding. I was lucky.


Can somebody help me with this one?  I need to check the answer  Let A denote the set of those 6-digit positive integers in which each of the digits 1; 2; 3; 4; 5; 6 appears exactly once. An integer in A; having standard decimal representation d1d2 : : : d6; is called nice if for each k = 1; 2; 3; 4; 5, the set fd1; : : : ; dkg contains at least one digit strictly greater than k (for example, 234561 is nice, whereas 321645 is not nice). From A; an integer n is randomly picked. What is the probability that n is nice?

Let A denote the set of those 6-digit positive integers in which each of the digits $1, 2, 3, 4, 5, 6$ appears exactly once. An integer in A, having standard decimal representation $d_1d_2 \cdots d_6$, is called nice if for each $k = 1, 2, 3, 4, 5$ the set {$d_1,.., d_k$} contains at least one digit strictly greater than $k$ (for example, 234561 is nice, whereas 321645 is not nice). From $A$, an integer $n$ is randomly picked. What is the probability that $n$ is nice?   My try:  Run the last digit from 1 through 6 and find the combinations by scanning the digits greater than the last digit across the first five positions in each of these scenarios.  It is pretty cumbersome and I am wondering if there could be anything simpler by means of symmetry or something like that as it does not give us any pattern. :  $234561 - 5!=120$  $345612 - 4*4! =96$  $456123 - 3*4!+3*3! = 90$  $561234 - 2*4!+4*3!+6*2! = 84$  $612345 - 1*4!+3*3!+8*2!+13*1! = 71$  $123456 - =0$  Total number of ways = $6! = 720$  Required probability = $$\frac{120+96+90+84+71}{720} = \frac{461}{720}$$  A simpler solution would be very much appreciated after verifying the answer.


for all $x\in \mathbb{R}$ and $n\in\mathbb{N}^*$ without using euclidian division.  First I re-write the sum in this way : $\sum \limits_{k=0}^{n-1} \lfloor x+\frac{k}{n}\rfloor = \lfloor x\rfloor+\lfloor x+\frac{1}{n}\rfloor+... +\lfloor x+\frac{i-1}{n}\rfloor+ \lfloor x+1-\frac{i}{n}\rfloor+...+\lfloor x+1-\frac{1}{n}\rfloor$   Now we can see that there is two possibilities for $x$ between two natural numbers $[q,q+1]$. Indeed we have the part $\sum \limits_{k=0}^{i-1}\lfloor x+\frac{k}{n}\rfloor=ji$ with $0\le j\le n$.And the other part $\sum \limits_{k=i}^{n-1}\lfloor x+1-\frac{k}{n}\rfloor=(j+1)(n-i)$.  Finally the floor will be $nj+(n-i)$.  Now for $\lfloor nx \rfloor$ it will be between $[nq,nq+q]$ which lets $n$ possibilities for its values but it would be perfect if it was $nj+(n-i)$ .  Thanks in advance !

Prove the following identity:   $$\lfloor x\rfloor +\lfloor x+\frac{1}{n}\rfloor +\lfloor x+\frac{2}{n}\rfloor +\lfloor x+\frac{3}{n}\rfloor+...+\lfloor x+\frac{n-1}{n}\rfloor =\lfloor nx\rfloor$$ where n is a Natural Number.   $$$$At first I thought of splitting it into 2 cases: when x is an integer, and when x isnn't an integer. The case of $x$ being an integer is quite simple: $\lfloor x+\frac{k}{n}\rfloor=x$ for $0\le k\le n-1$. Thus the LHS becomes $n\lfloor x\rfloor$ which is equal to the RHS. $$$$However I do not know how to go about the case of $x$ not being an integer.  Lastly, I would actually prefer a proof where it is not necessary to make cases based on the values of $x$, but to have one general proof which satisfies all $x$.  Could somebody please show me how to complete the proof in both ways (ie first, the case where $x$ isn't an integer, and secondly the general proof which doesn't involve breaking into cases)? Many thanks in advance!


Why is the number $e$ in Euler identity formula:  $$e^{iπ} = -1$$  I don't get it, why we use as base $e$.

From Euler we've learned that $z=re^{i\theta}$.  And it's easy to see that $|z|^2=r^2$, since $re^{i\theta}\times re^{-i\theta}=r^2$.  Why must we use e to represent these numbers correctly? It seems that I could arbitrarily choose a different exponent $z=r\pi^{i\theta}$ and get the same size for $z$ as I did before: $|z|^2=r\pi^{i\theta}\times r\pi^{-i\theta}=r^2$  What did I miss?


I’m new to this Linux stuff... I may have a fundamental misunderstanding, but I need some clarification on why getting the Ubuntu app on windows and using that terminal is so inferior (according to other Linux developers) than actually dual booting or solely using the Ubuntu distribution.  Thanks.

As most of you know, in the Microsoft Store, there are . This means that on Windows I can emulate Ubuntu and have the Ubuntu command line directly on Windows.  The question is very easy: what can’t I do from the Ubuntu command line emulated in Windows that I can do on a proper Linux-based Ubuntu? Is it useful to download this Ubuntu application, install it, and work just with it instead of the real OS? Is it possible to install all the development libraries? Can I write (or not) device drivers? In other words: what are the limits?  What features of Ubuntu Linux-based are missing from Ubuntu-on-Windows?  New answers are welcome: I know that every software is always changing by improving characteristics and features!


How does code download from PC to flash memory controller work? I mean what documents do IDE designers refer while designing this kind of software.   Are there any standard documents available for ST Microelectronics if one wishes to design a new IDE?

I want to build my own PIC programmer, can any one point me into right direction. Links, tutorials, books etc would be very helpful ? The programmer should use USB for communicating with the computer but even Serial port communication will also work?


After upgrading from mySQL 5.7 to 8.0 on freebsd, I keep getting the follow error, which prevents mysql to start: [ERROR] [MY-000067] [Server] unknown variable 'innodb_large_prefix=true'.  The thing is that setting is not on my my.cnf file. I understand it is deprecated on mySQL 8, but it is not on my configuration. Is there a way to fix it? Best, Francis

I am new to linux, and i just installed MySQL-server-5.1.59-1.glibc23.i386.rpm in my linux machine.   I wanted to know where my.cnf file gets stored..? Will my.cnf gets created with the installation or not..?  I am using Fedora core 13  Edited: Still i am not able to find this file. When i asked my admin, he is telling we need to copy my-large.cnf and place in /etc folder.. is it so...?


When setting the value of the primary command prompt (PS1) the followig two cases   export PS1="\u" export PS1="\\u"   gives the same result:  root   as a command prompt string. How does the \u and \\u differs if the both results is identical? Shouldn't the \\u outputs just \u since \\ denotes backslash itself?

Could some one explain what is happening behind the scenes in character escaping in Linux shell? I tried the following and googled a lot, without any success in understanding what (and how) is going on:  root@sv01:~# echo -e "\ Hello!" \ Hello! root@sv01:~# echo -e "\\ Hello!" \ Hello! root@sv01:~# echo -e "\\\ Hello!" \ Hello! root@sv01:~# echo -e "\\\\ Hello!" \ Hello! root@sv01:~# echo -e "\\\\\ Hello!" \\ Hello! root@sv01:~# echo -e "\\\\\\ Hello!" \\ Hello! root@sv01:~# echo -e "\\\\\\\ Hello!" \\ Hello! root@sv01:~# echo -e "\\\\\\\\ Hello!" \\ Hello! root@sv01:~# echo -e "\\\\\\\\\ Hello!" \\\ Hello! root@sv01:~# echo -e "\n Hello!"   Hello! root@sv01:~# echo -e "\\n Hello!"   Hello! root@sv01:~# echo -e "\\\n Hello!" \n Hello!   I am totally lost there, so for example, why do three backslashes give only one back slash? I would expect: the first two will be escaped to one, the third one will find nothing to escape so it will remain a slash (line in the first experiment), but what is happening is that the third one is just disappears. Why I am getting one backslash from four \\\\ Hello? I would expect each pair will give one back slash -> two backslashes.  And why I need three backslashes in the last case to get \n escaped? what is happening in background of escaping to get that? and how is it different from \\n case?  I appreciate any explanation of what is going on in the previous lines.


When the values are equal by using the equality operator , output shows Failure instead of success. Is this the problem with versions of compilers? Screen shot of the program attached  void main()         {             float k = 0.1;             if (k == 0.1)                 printf("Success");             else                 printf("Failure");         }

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


I'm working on an assignment that requires me to create an area column in miles without changing the projected coordinate system. ArcGIS has a tool that can do this ('Calculate Geometry')-- does QGIS have anything analogous? I know about using $area in the Field Calculator but I cannot tell what units the resulting answers are in.

How do I calculate areas of an area shapefile in square meters (m²) or in acres (ha)? I didn't find that functionality in the Vector Tools.


In MySQL, I could fire off these statements to insert 5 rows in one shot:  CREATE TABLE t (id int primary key auto_increment) INSERT INTO t VALUES (DEFAULT),(DEFAULT),(DEFAULT),(DEFAULT),(DEFAULT)   How can I do the same thing in MS SQL Server?  P.S.  The reason that the suggested duplicate doesn't solve the problem is that it has tables with non-identity columns.  My Table only has an identity column.

I have multiple set of data to insert at once, say 4 rows. My table has three columns: Person, Id and Office.  INSERT INTO MyTable VALUES ("John", 123, "Lloyds Office"); INSERT INTO MyTable VALUES ("Jane", 124, "Lloyds Office"); INSERT INTO MyTable VALUES ("Billy", 125, "London Office"); INSERT INTO MyTable VALUES ("Miranda", 126, "Bristol Office");   Can I insert all 4 rows in a single SQL statement?


I have to find out the number of positive integral solutions $(x,y)$ of  $$x^2-y^2=12345678$$  Specifically, if $S$ is the set of all ordered pairs $(x,y)$ then $S$ -  A) is an infinite set B) is the empty set C) has exactly one element D) is a finite set and has at least two elements.  Now, with a calculator capable of doing prime factorization, this is an easy question. However without a calculator, its very difficult to find the prime factors by inspection. What is the most efficient and fast solution to such a question. This question was asked  (Q no. 4)

This question appeared in KVPY online exam held on Nov 5. This equation is the equation of a hyperbola so any solution must be of the form $a\sec(k),a\tan(k)$. So no solutions.


if(class1.getMethod1().subString(0,1) == "1") && !class1.getMethod1().subString(0,1).equalsIgnoreCase(str1.subString(0,1)(shld be 1 or 2 or 3 )   i.e., String value is 1 or 2 or 3, then I should skip the if condition I am not able to give   !class1.getMethod1().subString(0,1).equalsIgnoreCase(str1.subString(0,1) == 1 or 2 or 3   Can someone help me with appropriate logic ?

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


In C#, ref and out keyword.  How to it affect memory management? Is there any difference in memory management for ref and out keyword?

I'm creating a function where I need to pass an object so that it can be modified by the function. What is the difference between:  public void myFunction(ref MyClass someClass)   and  public void myFunction(out MyClass someClass)   Which should I use and why?


I would like to ask this question, but I am not sure to what community it belongs:     I've been a frontend developer for some years, but sometimes I'm still   in doubt as to which HTML tag to use in a certain situation. Do you   know of any books or websites that gives authoritative explanations of   the most important tags and their usage? (I am looking for some more   synthetic resource than the w3 specification itself, as I find it most   of the times long-winded)   This doesn't seem to fit stackoverflow, because it's not a specific programming problem. I would like to gather resources on the matter: is there any community where this question would fit?

I have a question that I am quite sure does not belong to SO: it is a general, broad question about programming language implementation.  Also, I do not feel it belongs to CS, because it is not strictly computer science (it is more of an engineering question). To be honest, after reading  I was leaning towards CS, but then in the CS FAQ I read "(avoid questions where) there is no actual problem to be solved"  In general, I wonder where to go for questions that:   are not about theory (for those, I would go to cs.stackexchange) are not really practical programming problems (for those, I would go to SO) are not design questions (programmers)   The question I am referring to are something like "Are function calls always implemented using a stack?" "Under which conditions can I transform a function call into CPS, and how would I do that?" (general, not related to a particular piece of code).  Where do questions about programming "curiosities", where there is no actual problem to be solved belong? Or maybe they do not belong to stackexchange at all?


I am using wp_insert_term() to insert a large number of taxonomy terms from a csv file. The contents of that csv file might change occasionally. According to the codex, wp_insert_term() needs to run on add_action('init') but I only want to run it once. How can I achieve that on plugin activation?  I am currently just doing this in my plugin's constructor which runs on every page load:     add_action('init', array($this, 'add_geo_terms'));   and then  public function add_geo_terms() {       $path = plugin_dir_path( __FILE__ ).'assets/uk-counties.csv';     $row = 1;     if (($handle = fopen($path, "r")) !== FALSE) {         while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) {             $num = count($data);             $row++;             for ($c=0; $c < $num; $c++) {                 if ($c == 1) {                     error_log( $data[$c] . "<br />\n");                     wp_insert_term($data[$c],'reseller-regions');                 }             }         }         fclose($handle);     } }   I am using the activation functions provided by the  so I don't believe this is really a duplicate.  register_activation_hook( __FILE__, array( 'WPS_RESELLER', 'activate' ) );   public static function activate( $network_wide ) {         if ( function_exists( 'is_multisite' ) && is_multisite() ) {             if ( $network_wide  ) {                 // Get all blog ids                 $blog_ids = self::get_blog_ids();                  foreach ( $blog_ids as $blog_id ) {                     switch_to_blog( $blog_id );                     self::single_activate();                 }                 restore_current_blog();             } else {                 self::single_activate();             }         } else {             self::single_activate();         }     }  private static function single_activate() {     add_action('init', 'add_partner_terms'); // i have tried many variations with classname, self etc     add_action('init', 'add_geo_terms');  }

I'm making a WordPress plugin. What are typical things I should include in the uninstall feature?  For example, should I delete any tables I created in the install function?  Do I clean up my option entries?  Anything else?


I am wondering if there is a way to setup a local server to render blends on my network.  Work on a model on client, press a button through some add-on, send that file to the server for rendering. Is there anything like this?

I have quite a few computers at my disposal- about 100 mac pro's bought 2 years ago, just as many windows PC's of varying age (1-3 years), 50 linux machines and a good few terabytes of storage on a central server. I'm seriously considering getting everything together into a cycles render farm. How can I set something up easily and quickly which will make use of everything I've got?


Is there a way that I can search through which comments I've got the most upvotes from? I think it would be interesting.   It would also be nice to see other users high rated comments.   Does this kind of functionality exist? Could we add this?  Again, it's small, but would be a nice-to-have

I'm a little surprised no one asked this yet, but why isn't it possible to show your comments in descending order of "great comment" votes it has received? You can do this with upvotes on questions and answers, and since I think comments are the third major activity on SO, I'd like to view them. Even if you couldn't order them, it should at least show the number of votes on the activity#comments page of your profile...


How  forms? How diamonds sparkle? What is major cause happening for it and can you explain with examples?

I have always wondered why diamonds shine. Can anyone tell me why?


This is the code that I am working on right now:   def getWinner(userChoice, computerChoice):      if userChoice == "rock" and computerChoice == "scissors":        winner = userChoice     elif userChoice == "paper" and computerChoice == "rock":        winner = userChoice     elif userChoice == "scissors" and computerChoice == "paper":        winner = userChoice     elif userChoice == "rock" and computerChoice == "paper":        winner = computerChoice     elif userChoice == "paper" and computerChoice == "scissors":       winner = computerChoice     elif userChoice == "scissors" and computerChoice == "rock":       winner = computerchoice     elif userChoice == computerChoice:       winner = "It's a tie." return(winner)  userChoice = input("Enter your choice:") computerChoice = print(getComputerChoice()) winnerOfGame = getWinner(userChoice, computerChoice) print(winnerOfGame)   I am trying to set up a rock, paper, scissors game, but every time I try to run this function, it returns with:   Traceback (most recent call last):    File "C:/Python34/idk 2.py", line 45, in <module>     winnerOfGame = getWinner(userChoice, computerChoice)    File "C:/Python34/idk 2.py", line 41, in getWinner     return(winner) UnboundLocalError: local variable 'winner' referenced before assignment   I have tried assigning a global variable, but nothing seems to be working when I try to fix it. When I do other if statements like this, I do not have issues with the variable being referenced before assignment, and I am doing nothing differently.

The following code works as expected in both Python 2.5 and 3.0:  a, b, c = (1, 2, 3)  print(a, b, c)  def test():     print(a)     print(b)     print(c)    # (A)     #c+=1       # (B) test()   However, when I uncomment line (B), I get an UnboundLocalError: 'c' not assigned at line (A). The values of a and b are printed correctly. This has me completely baffled for two reasons:   Why is there a runtime error thrown at line (A) because of a later statement on line (B)? Why are variables a and b printed as expected, while c raises an error?   The only explanation I can come up with is that a local variable c is created by the assignment c+=1, which takes precedent over the "global" variable c even before the local variable is created. Of course, it doesn't make sense for a variable to "steal" scope before it exists.  Could someone please explain this behavior?


I have to run a JavaScript regex on URLs to detect any (one or more) special character after URL and put space before them, like:  url, --> url , or url), --> url ),   e.g.   (), into ( ),

How can I check if a given string is a valid URL address?  My knowledge of regular expressions is basic and doesn't allow me to choose from the hundreds of regular expressions I've already seen on the web.


I'm trying the following sample snippet  import org.openqa.selenium.WebDriver; import org.openqa.selenium.firefox.FirefoxDriver; public class Test { public static void main(String[] args) {      WebDriver driver = new FirefoxDriver();           driver.get("http://www.google.com");      //System.out.println("My new program");  } }   When I run this code, getting the following error.   Exception in thread "main" java.lang.NoClassDefFoundError: com/google/common/base/Function at Test.main(Test.java:6) Caused by: java.lang.ClassNotFoundException: com.google.common.base.Function at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ... 1 more   Firfox version is 48.0 Jar which added in eclipse is selenium-java-2.53.0, selenium-java-2.53.0-srcs.  Could anyone please help me to fix this issue.

I am getting a NoClassDefFoundError when I run my Java application.  What is typically the cause of this?


I can't get this command to work:  /summon Villager ~ ~1 ~ {Proffesion: 0,CustomName: “Ratigan”, CustomNameVisible: 1,Career: 1,CareerLevel: 42,Offers:{Recipes:[{buy:{id:minecraft:pumpkin},{id:minecraft:iron_block,Count:3},{id:minecraft:pumpkin}},sell:{id:minecraft:lever,Count:1,tage:CustomName:["SEcret passage under the well"],tag:{CanPlaceOn:["minecraft:iron_block"]}}}]}   It says: Unbalanced curly brackets {}, but I can't seem to find where I messed up. Can somebody help?

Often, when making a command block contraption, you need to set an entity's data tag. These tags can sometimes be very long, with many layers of nested curly and square brackets. For example, this is the command to summon a villager with a single custom trade:  /summon Villager ~ ~ ~ {Profession:3,Career:2,Offers:{Recipes:[{buy:{id:minecraft:diamond,Count:6b}},sell:{id:minecraft:diamond_hoe,tag:{ench:[{id:16s,lvl:10s}]}]}}   The single-line command block interface of Minecraft makes it incredibly difficult to find and fix errors, especially when it comes to mismatched brackets. In fact, for illustration purposes, I put an error in the above command.  What techniques can I use to find and fix unbalanced square or curly brackets when writing long and complicated data tags?


Prove using binomial formula $9 \mid 10^k - 1$ for $k \in \mathbb{N}$  I am aware of similar answer to this question  and  however my query is about the manipulation on the binomial formula in my proof. My attempt at the proof : We notice that $$10^k - 1 = (9 + 1)^k - 1$$ $$=\left(\sum_{i = 0}^{k} {k \choose i} 9^{k-i} \right) - 1$$ How do I further remove the -1 to show that this indeed is divisible by 9 ?

In respect to a larger proof I need to prove that $(n-m) \mid (n^r - m^r) $ (where $\mid$ means divides, i.e., $a \mid b$ means that $b$ modulus $a$ = $0$). I have played around with this for a while now but to no avail and would be grateful if you could help me.


I need to print the contents of my associative array to a file in bash.. The console output printing is working fine but when I try to print it to a file, only one element is getting printed. Here is my code  for KEY in "${!SYMBOLICLINK[@]}"; do     printf "$KEY --> ${SYMBOLICLINK[$KEY]}" > /tmp/symlinks.txt      # Print the KEY value      echo " $KEY --> ${SYMBOLICLINK[$KEY]}"       done     Can someone pls tell me what i am missing here I also went through this  but it didn't help

I often see tutorials online that connect various commands with different symbols. For example:  command1 |  command2 command1 &  command2 command1 || command2     command1 && command2   Others seem to be connecting commands to files:  command1  > file1 command1  >> file1   What are these things? What are they called? What do they do? Are there more of them?    .


I want to put text in a box where only two corners of the box are visible. I've explored using tikzpicture and a new md environment.

I want to trace a border in a box or minipage like this model. A border customizable in left angle on top and right angle in bottom. Somebody can help me? Thanks a lot JPierre


I have a web scraper, and I need the number to start at 000000001 as that's how the URL starts, however whenever I run it I get the "leading zeros in decimal integer literals are not permitted; use an 0o prefix for octal integers" error - which I tried to use but that doesn't solve my issue. Is there any way around this? Excerpt: results = [] START = 000000001 LIMIT = 100 END = START + LIMIT + 1 row = 1  for i in range(START, END):     URL = f"{url}{i}"     result = parse(URL)     if not result:         print("this url doesn't exist: ", URL)         continue     for column_number, column_value in enumerate(result):         worksheet.write(row, column_number, column_value)     row += 1

What is a Pythonic way to pad a numeric string with zeroes to the left, i.e. so the numeric string has a specific length?


hey when i create a file the logs show that file is created but it not existed in system, and while writing into that file it says null pointer exception is there anyone can help me please  try {   File root = android.os.Environment.getExternalStorageDirectory();   File dir = new File (root.getAbsolutePath()+ "/Sniffiing");   dir.mkdirs();   File file1 = new File(dir,"dump1.txt");   file1.createNewFile();   System.out.println(file1);  System.out.println("Hello Buddy what are upto.....##########################");   OutputStreamWriter os = new OutputStreamWriter(                                         new FileOutputStream(file1));   bw = new BufferedWriter(os);   Process process = Runtime.getRuntime().exec(                                         "logcat -v threadtime -s ServiceMode");    int length = process.toString().length();     System.out.println("Length" + length);     BufferedReader reader = new BufferedReader(                                         new InputStreamReader(process.getInputStream()));     StringBuffer output1 = new StringBuffer();     while ((line = reader.readLine()) != null) {      bw.write(line);      bw.newLine();    }  } catch (IOException e) {  }    here is Logcat  D/action: 0 D/ACTION:: BOTH D/Log3GState:: Accessing  file D/Create file: /data/user/0/com.services.snifspoof.snifspoof/C_packetCapture D/Log3GState:: Write executable  file D/EGL_emulation: eglMakeCurrent: 0x9ef850c0: ver 2 0 (tinfo 0x9ef831f0) D/EGL_emulation: eglMakeCurrent: 0x9ef850c0: ver 2 0 (tinfo 0x9ef831f0) D/CLOSING: BOTH I/System.out: *********############# I/System.out: *********############# File Created :- /storage/emulated/0/Sniffing/dump1.txt I/System.out: Length34            --------- beginning of crash E/AndroidRuntime: FATAL EXCEPTION: Thread-2  Process: com.services.snifspoof.snifspoof, PID: 2389  java.lang.NullPointerException: Attempt to invoke a virtual method on a null object reference  at com.services.snifspoof.snifspoof.MainActivity$3$1.run(MainActivity.java:167)  at java.lang.Thread.run(Thread.java:761)

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I have a table (id, serialnumber, status) of numbers and their statuses, need to take one with status 'unused' and change it's state to something like 'in work'. Can do it this way:  UPDATE serials SET status = 'in work' WHERE serialnumber IN (   SELECT "serialnumber"   FROM serials   WHERE status = 'unused'   ORDER BY id ASC    LIMIT 1 ) RETURNING serialnumber;   Is that the right way of selecting and updating a row in concurrent environment? It's unacceptable to take a serial when someone already took it.

I have a Postgres database which contains details on clusters of servers, such as server status ('active', 'standby' etc). Active servers at any time may need to fail over to a standby, and I don't care which standby is used in particular.   I want a database query to change the status of a standby - JUST ONE - and return the server IP that is to be used. The pick can be arbitrary: since the status of the server changes with the query, it doesn't matter which standby is selected.  Is it possible to limit my query to just one update?  Here is what I have so far:  UPDATE server_info SET status = 'active'  WHERE status = 'standby' [[LIMIT 1???]]  RETURNING server_ip;   Postgres doesn't like this. What could I do differently?


I can not figure out why my while loop won't break and it just keeps running I have tries making Lc 10 and I tried return but nothing will end the loop.  import java.util.Scanner; public class BirthdayReminder {     public static void main (String[] args)    {       Scanner input = new Scanner(System.in);       String[] BDay = new String[10];       String[] friend = new String[10];       int Lc = 0;       String i;        while(Lc < 10) {             System.out.println("enter a friends name or zzz to quit");             i = input.nextLine();             if(i == "zzz") {                  break;             }             else if(i != "zzz"){             friend[Lc] = i;             System.out.println("enter their birthday.");             i = input.nextLine();             BDay[Lc] = i;             Lc++;             return;             }       }       System.out.println("hi");     }   }

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


Given    I wonder why are there two photons entering in a) pair production? Isn't it one photon resulting in $e^+e^-$ ?

This is probably an obvious question, but I don't see it answered anywhere.  Imagine we have an object in the Universe that is traveling, relative to the Milkyway at about .99999999999999999999999999c and I realize that's not possible, but imagine.  Speed is relative, so to the object, the Milkyway is flying past it and to us, the object is flying past us.  That's all good and relative.  But the photons that our superfast object encounters are gonzo blue-shifted, and relativity says that's OK too.   But lets say the object is traveling so fast, the photons it encounters are energetic enough to spontaneously undergo pair production.  That seems difficult to explain.  A relatively low energy visible light photon to our perception won't split into an Electron and a Positron, but a very energetic photon can, but it's the same photon just observed by 2 different reference frames?    I understand that observers won't agree on when things happen or on energy but the two observers should agree on events that take place and pair production for one but not the other seems impossible.     Is there a simple layman's way that this can be explained?


Can I position all selected vertices to the same place?   I basically want to set all of their x positions to 0.

If you have a cluster of points selected like this:    how do you align the points so that they create a flat plane?


This is a kind of silly question, that mostly goes unanswered: are gravitons detatched from the objects they act on, like photons in free space.  Maybe gravity or gravitons are collected by mass (including black holes), as they are collected by the curve in spacetime caused by the mass. The origin of gravitons in such an arrangement seems phenominal in many respects, but could it be that space itself is just composed of evenly distributed graviton sources? these spill gravitons when a mass distorts it.

My understanding is that light can not escape from within a black hole (within the event horizon).  I've also heard that information cannot propagate faster than the speed of light.  It would seem to me that the gravitational attraction caused by a black hole carries information about the amount of mass within the black hole.  So, how does this information escape?  Looking at it from a particle point of view: do the gravitons (should they exist) travel faster than the photons?


How do I start?  I want to open a DXF or a DWG file and then to export it to a KML file to be used in google earth.  Have no idea how to start doing so.

I'm trying to convert a DXF 2010 file to KML using ogr2ogr:  ogr2ogr -f "KML" outfile.kml infile.dxf   In the file, $INSUNITS is 6, that's meters, if I'm correct? The problem is that DXF is not georeferenced, and I get errors like:  ERROR 1: Latitude -1113854.310000 is invalid. Valid range is [-90,90]. This warning will not be issued any more Warning 1: Longitude -684136.440000 has been modified to fit into range [-180,180]. This warning will not be issued any more   I'm pretty new to this stuff, and in the last weeks I haven't found documentation that's explaining what I'm doing wrong. Can I add a suggested lat/lon as a parameter to ogr2ogr? Is it actually possible to do a conversion DXF to KML?


When referring to commands in tutorials, man pages, and articles I see authors use the backtick and single quote in this way:  `./configure' `make'   I believe I have seen gcc denote points of failure during compilation with that sequence. Where does it come from and why do many people use it as a convention for commands to issue?

I've noticed that man pages and other documents formatted by Unix utilities often use double backticks `` followed by double single quotes '' to wrap quoted phrases instead of the double quote character ". Single quotes are similarly replaced. Why is this?  Here are a couple examples, from the man page for grep:   To find all occurrences of the pattern `.Pp' at the beginning of a line:         $ grep '^\.Pp' myfile   The apostrophes ensure the entire expression is evaluated by grep instead  of by the user's shell.  The caret `^' matches the null string at the  beginning of a line, and the `\' escapes the `.', which would otherwise match  any character.   The grep utility is compliant with the IEEE Std 1003.1-2008 (``POSIX.1'')  specification.


Frozen beef barley soup. Can I add more ingredients to thawed soup and safely re-freeze

What are the general rules regarding when can you refreeze food that was frozen and then thawed in the fridge? and what are the reasons behind them? (Hygiene? Food quality?). Let's assume for the sake of the argument that the items were in a non-frozen state only a few hours.  To be more specific, I'm interested in the application of these rules for  - Ginger garlic paste - Dough - Indian Curries - Green Chilly paste - Frozen green peas


Let $f:[0,\infty) \to[0, \infty)$ be a continuous function such that $$\int_0^{\infty} f(t) dt <\infty$$  then which of following  are true  (1) the sequence $\{f(n)\}$ is bounded  (2) $f(n) \to0$ as $n \to \infty$  (3) the series $\sum f(n)$ is convergent  i think option 1 and 2 is true, and option 3 is false.but not able to prove 1 and 2 and disprove 3.  any hint please

Let $f:[0,\infty)\to [0,\infty)$ be a continuous function such that $\displaystyle \int_0^{\infty}f(t)\,dt<\infty$. Which of the following statements are true ?   (A) The sequence $\{f(n)\}$ is bounded.  (B) $f(n)\to 0$ as $n \to \infty$.  (C) The series $\displaystyle \sum f(n)$ is convergent.  I am unable to prove directly but I am thinking about the function $f(x)=\frac{1}{1+x^2}$. For this function all options are correct. Is it correct ? I think not , as I have no proof in general.  Please help by giving a proof or disprove the statements.


Windows has just done an update and now when I open Blender 2.78c the top menu line has collapsed. Is there a way of setting it to be there, in preferences or startup?  Also the pointer now has to be a few mm below anything I want to select being it a menu item or anything else it seems to be offset.

I have a problem with Blenders UI. The "Info" bar on top disappeared and the mouse pointer is misaligned. I reinstalled Blender 2 times, deleted every leftover files  but it still does the same thing. This is in v2.78c. The weird thing is that on the bottom everything works fine. Here are some images:


A word or phrase that describes best a specific type of person or their behavior. The type of person that would not act upon a threat if said threat is not affecting their personal well-being directly.   Context: "Global warming becomes my problem only if I decide to believe I'll live long enough to see the consequences of it."   Proposals that are tightly related to the given context are more than welcome!

"The only thing necessary for the triumph of evil is for good men to do nothing." -Edmund Burke  Is there an idiom, phrase or preferably a single word that we can call people that could have helped but didn't? Bystanders don't necessarily have help to give. Cowards aren't particularly helpful either.    Addendum:  For example, once EMS has arrived on scene, bystanders are encouraged not to try to help, unless they're a nurse and therefore have the necessary skills to, and sometimes even then so. If in The Service, I would not want a coward (a liability) next me holding the line. Not to take anything away from these great answers, or to insist on a non-militaristic point of view, I would like to veer into the commercial or civilian realm in which I find this quote most often alluded to, E.G., "If we all gave 5 cents we could cure cancer tomorrow." Pretend most of us did give 5 cents and we did cure cancer, but you didn't give. You are now a(n) ____?... yes, I know what we call them, but what is their proper designation?


Is the following statement true ? If yes prove it and if no then give a counterexample?  Consider the finite cyclic group $\Bbb Z_n$. Consider $a,b\in \Bbb Z_n$ such that  $o(a)=r,o(b)=s$. If $s\mid r$ then $b\in \langle a\rangle $. Initially I thought the statement is correct. But the problem is I am unable to prove it. How to prove it?

Lemma $1.92$ in Rotman's textbook (Advanced Modern Algebra, second edition) states, Let $G = \langle a \rangle$ be a cyclic group. (i) Every subgroup $S$ of $G$ is cyclic. (ii) If $|G|=n$, then $G$ has a unique subgroup of order $d$ for each divisor $d$ of $n$.  I understand how every subgroup must be cyclic and that there must be a subgroup for each divisor of $d$. But how is that subgroup unique? I'm having trouble understanding this intuitively. For example, if we look at the cyclic subgroup $\Bbb{7}$, we know that there are $6$ elements of order $7$. So we have six different cyclic subgroups of order $7$, right? Thanks in advance.


I'm looking for ubuntu image which has only cli. I want install it on my windows pc through VM Box. I don't like switching from GUI to CLI or changing grub files.   Where I can get pure cli ubuntu os image?   Thanks.

I am using an Ubuntu 12.04 lts and I don't need the GUI, so I changed the grub to start as text mode, but since I don't use the GUI, I want to delete all about it to save space.   I tried "sudo apt-get remove ubuntu-desktop", but there is still the same GUI as before.  What can I do?  Thanks.


I came across a question asking whether there is a limit to the magnetism of an electromagnet.

What's the theoretical potential for how strong electromagnets can get? If you just kept coiling a solenoid longer and wider, and fed more and more current into the coil, would the field strength in the middle get arbitrarily dense?  This is the closest related question I could find:   I understand that the core will eventually saturate and thus stop helping to increase the field. But I think increasing the other parameters still makes for a stronger magnet.


$21x \equiv 49 \pmod{10}$? 21 % 10 = 1 and 49 % 10 = 9 So we can rewrite this as $1x \equiv 9 \pmod{10}$ But which theorem shows that we can substitute the LHS & RHS with the remainder?

I have seen other criteria for divisibility by 7. Criterion described below present in the book Handbook of Mathematics for IN Bronshtein (p. 323) is interesting, but could not prove it. Let $n = (a_ka_{k-1}\ldots a_2a_1a_0)_{10} = \displaystyle{\sum_{j=0}^{k}}a_{k-j}10^{k-j}$. The expression $$ Q_{3}^{\prime}(n) = (a_2a_1a_0)_{10} - (a_5a_4a_3)_{10} + (a_8a_7a_6)_{10} -\ldots  $$ are called alternating sum of the digits of third order of $n$. For example,  $$ Q_{3}^{\prime}(123456789) = 789-456+123=456 $$ Proposition: $7 | n \ \Leftrightarrow \ 7 | Q_{3}^{\prime}(n)$.  proof. ??  Thanks for any help.


If I answer as an 'answer' I get the good-looking UI to help me do all the things I want, BUT if I am in comments I am helpless. Would it take much resources to have the same same UI to keep sanity in answers too ?    The other query is, is there a way to test the output/look as we do when framing a question? For people who are not so good at markdown will appreciate if this can be done.   Lastly I tried retext and saw the preview there of the comment till I was happy with. Copying and pasting it there makes it a jumble.   $ aptitude show retext Package: retext                           State: installed Automatically installed: no Version: 5.0.0-1 Priority: optional Section: editors Maintainer: Dmitry Shachnev <mitya57@gmail.com> Architecture: all Uncompressed Size: 417 k Depends: python3-markups, python3-pyqt5, python3-pyqt5.qtwebkit, python3:any (>= 3.3.2-2~) Recommends: docutils-common (>= 0.10-3~), python3-enchant, python3-markdown | python3-docutils, shared-mime-info (>= 0.91) Breaks: retext-wpgen (< 4.0~) Replaces: retext-wpgen (< 4.0~) Description: Simple text editor for Markdown and reStructuredText  ReText is a simple editor for Markdown and reStructuredText markup languages.    ReText supports tabs, live text preview and syntax highlighting. Supported export formats: HTML, ODT, PDF. It is also possible to write custom  export extensions.    It is written in Python using Qt libraries. Homepage: http://retext.sourceforge.net/   Hoping people can help.   The comment in question for now is  but there have been other comments where I had same issues.

Hello  I would like to see changes in the comment section. Presently, we cannot start a new line. Everything gets posted in one line. Even the code looks horrible.   Also, to color the code in comments.


Can I connect five 100μF capacitors in series or parallel to form 500μF in total that I can use like a regular 500μF capacitor? (Apologies for noob question.)

this time I'd like to ask a few questions about capacitors, all noob questions again;   What's a better idea, having one capacitor at 5x farads or five capacitors at x farads each? I want to get a certain amount of voltage and want to discharge the direct current as fast as possible. I'm trying to build an amateur railgun, and intend to shoot projectiles that weigh about 10 grams. Using the formula that someone helped me with in my other question, in order to give that a speed of 100m/s at a total of 20.000 uF assuming 2% efficiency I'd need a little less than 112V's. The question is, is this amount of voltage I need my capacitor or series of capacitors to provide for the duration of the shooting? What determines how much voltage a capacitor can hold? This may come off stupid as I am aware that there is a voltage rating when you buy them, but better safe than sorry. I was only assuming 2% efficiency, and depending on my rail length it could be higher. The question is, what determines how fast the capacitor will discharge and how it can be prevented from going above the rated voltage?


I'm running a small web application with SQL server express (2005) as backend. I can create a backup with a SQL script, however, I'd like to schedule this on a  daily basis. As extra option (should-have) I'd like to keep only the last X backups (for space-saving reasons obviously) Any pointers?  [edit] SQL server agent is unavailable in SQL server express...

What are the recommendations of software products for creating automated backups of SQL Server 2008 databases?  The backup should happen without taking the database offline/detatching.


At $z=0$, the function $$f(z)=\exp\left(\frac{z}{1-\cos(z)}\right)$$ has infinitely many positive and negative powers of $z$.  I want to determine whether it is True or False.  Taking $\lim_{z\to 0} f(z)$, we note that limit does not exist so the singularity at $z=0$ is essential which means there are infinitely many negative powers of $z$ in the Laurent series expansion of $z$.  But I am not able to see why it should have positive powers.   I tried looking at series expansion of $f(z)$ which turned out to be  $$1+{z\over 1-\cos(z)}+ ({z\over 1-\cos(z)})^2{1\over 2!}+\dots$$  but  I am not able to properly argue about why infinitely many positive powers of $z$ should be present.

At $z=0$ the  function $f(z)=\exp({z\over 1-\cos z})$ has    $1$. A removable singualrity  $2$. A pole  $3$. An essential singularity  $4$. Laurent series around $z=0$ has infinitely man positive and negative power of $z$  I see $\lim_{z\to\infty}f(z)=\infty\cup -\infty$ if you approach to $0$ from left and right side of the real line, so $f$ can not be bounded near $0$ so it has $f$ essential singularity?


Imagine sometime in the distance future where the expansion of the Universe has created vast areas of empty space, light years wide.  Imagine, say, a neutron and a neutrino bound together as a gravitationaly bound atom. The "atom" in it's lowest energy state would be several light years across such is the weakness of the gravitational force.  Presumably the atom could jump to a higher energy state by absorbing a graviton.   Zooming out of this picture so that a light year looks only a few cm wide, would this look in any way like a normal atom but just on a vastly different scale?  Could these gravitational atoms form molecules?  Are the rules of these quantum gravitational systems known? Or does one need some unknown quantum theory of gravity?  In the distant future could most of the matter be made up of these gravitationaly bound atoms?

The quantum mechanics of Coloumb-force bound states of atomic nuclei and electrons lead to the extremely rich theory of molecules. In particular, I think the richness of the theory is related to the large mass ratio between the nucleon and the electron. This mass ratio leads to the Born-Oppenheimer approximation which gives rise to a complicated effective potential for the nuclei which posses many local minima: the molecules.  I wonder whether there are analogical phenomena in which the bound states are gravitational. It seems that if we take a collection of electrically neutral molecules and neutrinos, it should be possible to form a large number of bound states, in particular because of the large (not so long ago deemed infinite) mass ratio between molecules and neutrions. Of course neutrinos are highly relativistic and I can't tell how it affects things.  Now, even if we leave neutrinos alone, the typical size of such a bound state is  $$\frac{\hbar^2}{G  m^3}$$  where $m$ is proton mass. Google calculator reveals this to be 3.8 million light years. Holy moly! However, this is still much smaller than the observable universe. Can there be places in the universe sufficiently empty to contain such bound states? What would be the effect of general relativistic phenomena (expansion of space)? EDIT: I guess no place is sufficiently empty at least because background radiation is everywhere. Maybe these creatures will become relevant in a very distant future when the background radiation cools off considerably?  Summing up:     What is known about the quantum mechanics of gravitational bound states of electrically neutral molecules and neutrinos?   I'm tagging the question as "quantum gravity" since it involves gravity and quantum mechanics. Of course it is not quantum gravity in the usual sense of studying Planck-scale phenomena. I think the tag is still appropriate  EDIT: Gravitional bound states of molecules will often be unstable with respect to collapse to a van der Waals bound state (thx Vladimir for bring up the issue of vad der Waals interaction in the comments). However the lifetime of these states is very long.


When I try to type an ordered pair like (x,y) over an arrow in a tikz-cd I get the following error message:  Missing \endcsname inserted.   The code that works looks like this:  \begin{tikzcd}             A\arrow[r, ""]\arrow[d, ""] &   B\arrow[d, ""]\\\             C\arrow[r, ""]              &   D. \end{tikzcd}   The code that doesn't work looks like this  \begin{tikzcd}             A\arrow[r, "(x,y)"]\arrow[d, ""]    &   B\arrow[d, ""]\\\             C\arrow[r, ""]                      &   D. \end{tikzcd}

I was getting scope errors on a commutative diagram, and adding {} inside the quote marks eliminated the error. Why and under what circumstances are they needed.  This fails:   \ar[d, "\operatorname{g}_{\sigma_\beta}, \beta \prec \Beta_\gamma"]   This works:   \ar[d, "{\operatorname{g}_{\sigma_\beta}, \beta \prec \Beta_\gamma}"]


I've noticed some issues with Apache virtual hosts on two Macs that otherwise have the same kind of set up (in terms of httpd.conf, vhosts, hosts etc.) On one Mac, virtual hosts are served without a glitch, on another, I am getting connection refused on port 80.  This doesn't seem to be a problem with Apache configuration, I think, but something to do with ports.   Namely, the machine that fails to serve the virtual host test.dev on 80 shows me this on port scan:  Сканирование портов выполняется…  Port Scanning host: 127.0.0.1       Open TCP Port:     88          kerberos      Open TCP Port:     445         microsoft-ds      Open TCP Port:     548         afpovertcp      Open TCP Port:     631         ipp Сканирование портов завершено…   The machine that does serve test.dev show this:  Port Scanning host: 127.0.0.1       Open TCP Port:     22          ssh      Open TCP Port:     53          domain      Open TCP Port:     80          http      Open TCP Port:     88          kerberos      Open TCP Port:     445         microsoft-ds      Open TCP Port:     548         afpovertcp      Open TCP Port:     631         ipp Сканирование портов завершено…   So on the "good" machine, port 80 is listed, on the "bad" machine it isn't.  On both machines I have apache listening to *:80 etc, properly set up vhosts, an appropriate entry in the hosts file etc. Both Macs are running El Capitan, are on the same network etc.   And while on the good mac, test.dev is served, on the bad mac, I get this:  ↪ curl -I -L test.dev                                                                                15:51:01 curl: (7) Failed to connect to test.dev port 80: Connection refused   I'm at a bit of a loss, because I don't know how to fix this. Why is port 80 not showing up in the port scan of the bad Mac (using the Network Utility app), yet sudo lsof -i -P | grep -i "80"gives me:  httpd     4482           root    5u  IPv6 0xfe89d5ee2c7da24b      0t0  TCP *:80 (LISTEN) httpd     4484         daemon    5u  IPv6 0xfe89d5ee2c7da24b      0t0  TCP *:80 (LISTEN) httpd     4485         daemon    5u  IPv6 0xfe89d5ee2c7da24b      0t0  TCP *:80 (LISTEN) httpd     4486         daemon    5u  IPv6 0xfe89d5ee2c7da24b      0t0  TCP *:80 (LISTEN) httpd     4487         daemon    5u  IPv6 0xfe89d5ee2c7da24b      0t0  TCP *:80 (LISTEN) httpd     4488         daemon    5u  IPv6 0xfe89d5ee2c7da24b      0t0  TCP *:80 (LISTEN)   Many thanks in advance.   All best, Tench  Edit: I was asked to justify why this is not a duplicate question to the more general question about connection refused. It isn't because my question was specific to Mac OSX and the solution that worked for me (see below) required editing pf.conf and using pfctl which is not mentioned in the supposed duplicate question at all.

This is a  about Connection Refused    We see a lot of questions to the effect      When I try to connect to a system I get a message      Connection refused      Why is this ?


Suppose a pin can be set to three modes, high (5V), low (0V), and high impedance (?V). What is the voltage associated with high impedance? I.e. if I stuck a probe on a pin set to high impedance, what voltage would I read?  Does high impedance mean no current? If so, does that mean voltage measured would be 0 because of V=IR? If so, how would you differentiate high impedance and logic level low?

I would like to measure that voltage of a floating GPIO on a Raspberry Pi 3. When I use a multi meter or an oscilloscope it looks like the pin is pulled to ground and shows 0.  Another way of asking the question is, 'How can I determine if a GPIO pin is floating using an oscilloscope or multi-meter?"  How can I use an oscilloscope to measure the voltage of a floating GPIO pin on a Raspberry Pi?


My BSc thesis was on general relativity MY MSc thesis was going to be on modified theories of gravity and cosmology, in hope of pursuing a PhD in this area or similar one day.  I know replies are going to be why would you want to do a PhD in an area you don't want to do master's level research at.  However, modified theories of gravity and cosmology would be my second choice right now, just from brief reading around, I don't think it's going to compare to the excitement of first learning general relativity and I did some reading around for PhD interviews- I got short-listed a fair amount and was told my academia and project description were strong and good enough, but really my lack of enthusiasm let me down-which is the story of my life because I'm a bit shy, anyway, so I just fancy a bit of a break from it, and I was thinking of a topic that involves a bit of pure maths as well as mathematical physics.  I guess pretty much my question is can you get a PhD in an area you didn't do your masters thesis?  Would it significantly lower my chances.  Could it perhaps be the case that I really enjoy my master's thesis and want to pursue a PhD in this instead?  Thanks

I am a Physics undergrad who is interested in pursuing a PhD in pure maths in the future (algebraic geometry/topology) but I am a bit unsure. My question is quite general, and I don't wish to provide more background for fear of bias in the answers.  My question: Is it is advisable/possible/unfavorable/favorable to apply for a PhD in a field, different from that in which you have done most of your undergraduate research?  My research (includes just reading and understanding papers, writing summaries until now, I havent published anything) mostly includes Quantum field theory, and gauge theory. Would the selection committee turn down an application to a pure maths field, if I have no research experience whatsoever?  I would also like to ask the question other way round. What if I concentrate my undergraduate research SOLELY on topics in pure maths such as algebraic geometry/topology and take other physics courses, would I be able to apply to a string theory PhD with a high chance of success?  Should I consider spending time on both of these (which is almost an impossible task), to improve my chances in both the areas or would research in one area, and grad level courses in the other suffice?  In brief: Should the PhD field you are applying to be the same as your undergraduate research area?


For example, I want to plot a graph whose  is [0,1,0;1,0,1;0,1,0]. I first plot three points labeled by p1,p2,p3, and link the points p1,p2, p2,p3. For a general case, how to link the points according to the adjacency matrix(which may be stored in a .txt file)?


This is very embarrassed. I installed psensor from its source code, but now when I wan t to run it:  $ psensor The program 'psensor' is currently not installed.  You can install it by typing: sudo apt-get install psensor   I also want to add it to startup applications, so how can I find the location of its executable?  Some information about it is  $ dpkg -l psensor Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) ||/ Name           Version        Description +++-==============-==============-============================================ ii  psensor        1.0.4-1        psensor-1.0.4 installed from source on oct 1   $ man -k psensor psensor (1)          - Temperature monitoring application   Thanks.

Context: I'm trying to make an application automatically start when I login. For this I need to select the path for the application.     Here are the paths I already looked into:   /sbin /usr/sbin /usr/local/bin /usr/share/   If this may help, the application I'm trying to find is called "" and I downloaded it from the Ubuntu Software Center.  But I cannot find it, is there any way I can know where is installed a particular software? Because even if I found for this one, I would like to avoid having the same issue in the future.


I currently use Windows 10 and I'm running Minecraft 1.8.   I have seen people say run %appdata&\.minecraft\ but that never worked for me. I really want to download a mod, but I can't until I find this folder.

I don't have a minecraft folder. I've looked through forums and videos, followed all the steps. I just don't have one. I have windows 7, and I have "view hidden files" turned on. I have look in the roaming folder of my app data folder, with hidden files turned on. I want to find my folder so I can install a mod, could someone please tell me why my folder isn't showing up?


I have a S3 static page in a bucket and have added a Cloudfront distribution in front of it to access the webpage.  Now my question is: Is it possible to read the headers received by the webpage when the page is loaded? Is there a way I can print the headers on the webpage ?  Note: Im NOT about the response headers or the request headers before making a call from the client like mentioned over here:   Im asking the same question as over here:  for which there is no answer

I want to capture the HTTP request header fields, primarily the Referer and User-Agent, within my client-side JavaScript.  How may I access them?    Google Analytics manages to get the data via JavaScript that they have you embed in you pages, so it is definitely possible.     Related:


I get the error shown below while trying to implement dependent dropdown for country state as shown below while trying to submit form which implements  AJAX in drupal 8 for country - state dropdown I get the error  Error "An illegal choice has been detected. Please contact the site administrator.". How can I make sure default value of State is retained like its retained for Country ?
    namespace Drupal\custom_changes\Form;  use Drupal\Core\Form\FormBase; use Drupal\Core\Form\FormStateInterface; use Symfony\Component\DependencyInjection\ContainerInterface; use Drupal\custom_changes\NameTable\NameTable; use CommerceGuys\Addressing\Subdivision\SubdivisionRepository;  /**  * Simple Form  *   */ class CustomDicForm extends FormBase {   /**    * @inheritdoc    */   public function buildForm(array $form, FormStateInterface $form_state )   {      $form['country'] = [       '#type' => 'select',       '#title' => $this->t('Country'),       '#options' => [         '' => t('Select'),         'IN' => t('India'),         'GB' => t('UK (Great Britain)'),       ],       '#ajax' => [         'callback' => '::stateCallback',         'event' => 'change',         'wrapper' => 'state-list',         'progress' => [           'type' => 'throbber',           'message' => $this->t('Updating States...'),         ],       ],     ];     if (isset($form['#options'])) {       $form['state'] = [         '#type' => 'select',         '#prefix' => '
',         '#suffix' => '
',         '#title' => $this->t('State'),       ];     }     else {       $form['state'] = [         '#type' => 'select',         '#prefix' => '
',         '#suffix' => '
',         '#title' => $this->t('State'),         '#options' => ['' => t('Select')],       ];     }     $form['submit'] = [       '#type'=> 'submit',       '#value' => t('Submit'),     ];      return $form;   }   public function stateCallback(array &$form, FormStateInterface $form_state) {      $country = $form_state->getValue('country');      $form_state->setValue('state', '');      $form['state']['#options'] = ['' => t('Select')] + $this->getAllStates(        $country      );       return $form['state'];   }    /**    *     *  Get the State from Country    *  @return array $states    *    */    public function getAllStates($country) {     if ($country == "GB") {       // as GB does not give values so adding hard coded values       return ['A','B','C','D','E','F'];     }     else {       $subdivisionRepository = new SubdivisionRepository();       // Get the subdivisions for Brazil.       $states = $subdivisionRepository->getAll([$country]);       $in_states = array();       foreach ($states as $key => $state) {         $in_states[] = $key;       }     }     return $in_states;   }    /**    * @inheritdoc    */   public function getFormId()   {     return 'custom_changes_dic_name_form';   }    /**    * @inheritdoc    */   public function submitForm(array &$form, FormStateInterface $form_state)   {     parent::submitForm($form, $form_state);     $form['country']['#default_value'] = $form_state->getValue('country');     $form['state']['#options'] = ['' => 'Select'] + $this->getAllStates($form['country']['#default_value']);     $form['state']['#default_value'] = $form_state->getValue('state');     $first_name = $form_state->getValue('first_name');       $last_name = $form_state->getValue('last_name');     //@todo check how to pass exception     $this->nameTable->insertData($first_name, $last_name);     }  }

I have a form with only a select element and no submit button. Upon change, I issue an ajax call to retrieve the details of the selected Project. Everything works as expected, however after I leave the page, I see the error "An illegal choice has been detected. Please contact the site administrator."  I only get the error if I change the select input. Ex. if I navigate to:     Home->Projects->Home   I don't see the error on the last Home page. If i navigate to:     Home->Projects(change select input)->Home   I see the error on the last Home page.  Here is my module code:  class ExpeditionController extends ControllerBase {   public $client;    public function __construct() {     $this->client = \Drupal::service('http_client');   }     public function listProjects() {     $select_form = \Drupal::formBuilder()->getForm('Drupal\myModule\Form\ExpeditionSelectForm');     // Remove the submit button.     unset($select_form['actions']['submit']);      $result = $this->client->get('myRESTService', ['Accept' => 'application/json']);     $expeditions = json_decode($result->getBody());      foreach ($expeditions as $value) {       $select_form['expeditions']['#options'][$value->{'expedition'}->{'expeditionId'}] = $this->t($value->{'expedition'}->{'expeditionTitle'});     }      return array(       '#theme' => 'myModule_expeditions',       '#form' => $select_form,     );   }    public function expeditionDetail($form, $form_state) {     $expedition = [];     $response = new AjaxResponse();     if ($form['expeditions']['#value'] != "") {        $client = \Drupal::service('http_client');       $result = $client->get(         'myService' . $form['expeditions']['#value'],         ['Accept' => 'application/json']       );       $expedition = json_decode($result->getBody());     }      $response->addCommand(new HtmlCommand(       '#expeditionDetail',       array(         '#theme' => 'myModule_expeditions_detail',         '#expedition' => $expedition,       )     ));      return $response;   }    public function deploymentDetail($project_id, $deployment_id) {     $result = $this->client->get(       'myService' . $project_id . '/' . $deployment_id,       ['Accept' => 'application/json']     );      return array(       '#theme' => 'myModule_deployment_detail',       '#deployment' => json_decode($result->getBody()),     );    } }  class ExpeditionSelectForm extends ConfigFormBase {   /**    * {@inheritdoc}    */   public function getFormId() {     return 'myModule_expeditions';   }    /**    * {@inheritdoc}    */   public function buildForm(array $form, FormStateInterface $form_state) {     $form['expeditions'] = array(       '#type' => 'select',       '#title' => $this->t('Choose Project'),       '#empty_option' => $this->t('Select a project'),       '#default_value' => '',       '#ajax' => [         'callback' => 'Drupal\myModule\Controller\ExpeditionController::expeditionDetail',       ],     );      return parent::buildForm($form, $form_state);   }    /**    * Gets the configuration names that will be editable.    *    * @return array    *   An array of configuration object names that are editable if called in    *   conjunction with the trait's config() method.    */   protected function getEditableConfigNames() {     // TODO: Implement getEditableConfigNames() method.     return [];   } }


example shows how to produce PDF slides with syntax highlighting of source code. The example uses beamer and (presumably) pdflatex.     example shows syntax coloring for HTML output using htlatex. It's an unpleasant kludge   it precludes calling pdflatex on the same LaTeX file one must experiment to find what ectt-1000 maps to one defines colors for css categories, not for code syntax categories   but it works.  The following code revisits this problem and asks to do better.  \documentclass{article} \usepackage{color} \usepackage{listings} \usepackage[T1]{fontenc}  \lstset{     basicstyle=\ttfamily,     language=C++,     keywordstyle=\rmfamily\bfseries,     commentstyle=\sffamily, }  \begin{document}  \Css{div.lstlisting .ectt-1000 {font-family: monospace;color:blue}} \Css{div.lstlisting .ecss-1000 {font-family: monospace;color:green}} \Css{div.lstlisting .ecbx-1000 {font-family: monospace;color:red}}  \section*{Inserting source code} \begin{lstlisting} #include<stdio.h> #include<iostream> // A comment int main(void) {     printf("Hello World\n");     return 0; } \end{lstlisting}  \end{document}   Now commenting out the \Css lines and running pdflatex gives one output    and processing with htlatex gives another.    Can you suggest a way to make this kludge more usable by   correlating the two "blue" colors—even though ultimately one is defined in LaTeX's color package and the other in HTML, making the \Css definitions point to colors through syntax category, making it possible to process the file with pdflatex while writing/for debugging (htlatex is considerably slower)   ?

I'm trying to convert some LaTeX into HTML but my code listings don't preserve their code coloring. Why is that and how do I fix it?  This is what it looks like:    Side note: I'm also wondering why the caption on the table was removed.  Edit  Here is an example listing with colors:  \documentclass{article} \usepackage{color} \usepackage{listings} \lstset{     basicstyle=\footnotesize\ttfamily,     language=[Sharp]C,      keywordstyle=\color[rgb]{0,0,1.0}\bfseries,       commentstyle=\color[rgb]{0.133,0.545,0.133}\bfseries, }  \begin{document} \begin{lstlisting} int x = 10;  // This is a comment string str = "hello"; \end{lstlisting} \end{document}   This produces the following HTML when doing: htlatex myfile.tex:  <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"     "http://www.w3.org/TR/html4/loose.dtd">     <title></title>  <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">  <meta name="generator" content="TeX4ht (http://www.cse.ohio-state.edu/~gurari/TeX4ht/)">  <meta name="originator" content="TeX4ht (http://www.cse.ohio-state.edu/~gurari/TeX4ht/)">    <meta name="src" content="LaTeX4.tex">  <meta name="date" content="2012-07-20 12:30:00">  <link rel="stylesheet" type="text/css" href="LaTeX4.css">
int&#x00A0;x&#x00A0;=&#x00A0;10;&#x00A0;
&#x00A0;
//&#x00A0;This&#x00A0;is&#x00A0;a&#x00A0;comment&#x00A0;
string&#x00A0;str&#x00A0;=&#x00A0;"hello";
     Which looks like this:    I would want the HTML result to look like this:


Let us assume that $k$, $f(1)$, and $f(0)$ are constants. I am trying to find a closed form expression for $f(a)$, $a >= 2$ in terms of $k$, $f(1)$, and $f(0)$. I have to tried to recursively substitute values for $f(a)$ to try and generate a pattern. \begin{eqnarray} f(2) &=& k f(1) - f(0) \newline f(3) &=& (k^{2}-1) f(1) - k f(0) \newline f(4) &=& k(k^{2}-3) f(1) - (k^{2}-1) f(0) \newline f(5) &=& (k^{4}-3k^{2}+1) f(1) - k(k^{2}-2) f(0) \end{eqnarray} However, this is perhaps not the right way to approach this problem, and I'm looking for alternative ways to solve it?

Given a recurrence relation:   $$ x_{n+2} = px_{n+1} + qx_n + r $$   Find the general term $x_n$ given initial conditions $x_1 = a$ and $x_2 = b$, where $a,b,p,q,r$ are some given numbers, $n \in \mathbb N$.   Since this is a non-homogeneous linear recurrence relation i've started with solving for $x_n^h$ which is a solution for homogeneous relation:  $$ x_{n+2} - px_{n+1} - qx_n = 0 \\ \lambda^2-p\lambda - q = 0 $$  I'm assuming here that two distinct roots $\lambda_{1,2}$ exist for this equation (single root case is handled similarly). So the general term is in the form:  $$ x_n = C_1\lambda_1^{n-1}+C_2\lambda_2^{n-1} $$  With the initial condition it's possible to find the values for $C_1$ and $C_2$:  $$ C_1 + C_2 = a \\ C_1\lambda_1 + C_2\lambda_2 = b $$  After solving the system of equation with respect to $C_1$ and $C_2$:  $$ C_1 = \frac{b-a\lambda_2}{\lambda_1 - \lambda_2} \\ C_2 = \frac{b-a\lambda_1}{\lambda_2 - \lambda_1} \\ $$  Which eventually results in:  $$ x_n^h = \frac{(a\lambda_2 - b)\lambda_1^{n-1} - (a\lambda_1-b)\lambda_2^{n-1}}{\lambda_2 - \lambda_1} $$  Final solution consists of a sum of particular and homogeneous solutions, but that is where I got stuck. What is the way to find the particular solution for the given problem? I'm pretty new to such kind of problems so any details are very much appreciated.  upd:  Based on the technique in @rtybase answer here are my findings:  $$ \begin{align} x_1 &= a \\ x_2 &= b \\ x_3 &= pb - qa + r \end{align} $$  Writing the system for $c_1, c_2, c_3$:  $$ \begin{align} a &= c_1 + c_2 + c_3 \\ b &= c_1\lambda_1 + c_2\lambda_2 + c_3 \\ pb+qa+r &= c_1\lambda_1^2 + c_2\lambda_2^2 + c_3 \end{align} $$  Now solving for the coefficients gives a huge formula. The answer to this problem suggests that:  $$ x_n = \frac{(\lambda_2(a+\gamma) - b -\gamma)\lambda_1^{n-1} - (\lambda_1(a + \gamma) - (b-\gamma))\lambda_2^{n-1}}{\lambda_2 - \lambda_1} - \gamma $$  Where:  $$ \gamma = \frac{r}{p+q-1} $$  Unfortunately I was not able to arrive at exactly the same result, but testing my solution (not posting since it's monstrously big) using SameQ in Mathematica with the given answer shows that they are equivalent. Those transformations are not very obvious to me, so i skipped them since the answer matches the given one (yet the symbolic expressions are different)


I am authoring a LaTeX document with a co-author. The document is a single, monolithic one. We are working on two separate copies of the same document. Once one of us is done with his section, we are merging it together and updating out local copies. It has become a headache. Is there a better way to collaborate authoring LaTeX document?

Are there any tools for simultaneous collaborative editing of a .tex file?  The practices I know (and practice) in writing scientific papers are:   e-mailing each new version to the collaborators, working in a same Dropbox folder.   However, both are not meant for simultaneous editing, and are somewhat annoying.  EDIT:  A list is also here:


I followed many many tutorials but it doesn't work. I want to install the compat-drivers which include the negative-one-patch. In airodump-ng I always get the error: mon0 is on channel -1, but the AP uses channel...  I tried many OS, like Ubuntu 13.04, 12.04/10 and Neptune 3.1 from ZevenOS. I also tried BackTrack but it doesn't boot.  The only thing I want is to install succesfully the compat-drivers.  If so, could anyone help me, it would be very nice! Thank you very much!

I am beginner in Ubuntu 12.04, and have a problem with aircrack-ng. airodump-ng gived me a fixed channel -1 error. The access point is on channel 5, but I can't switch to that channel because of that error.  My hardware is: Broadcom BCM431, driver b43. I've tried patching,  but had a problem with driver installation.


Let $f$ be a continuous function defined on $[a, b]$. Assume that there exist constants $α$ and $β$ with $(α ≠ β)$ such that   $$\alpha\int_a^x f(u)du + β\int_x^bf(u)du = 0 $$ for all $x$ belonging to $[a,b]$. Show that $f(x) = 0 $ for all $x$ belonging to $[a,b]$.   My attempt: if we take $x = a$, then we get $\int_a^bf(x)dx = 0$. However this does not imply $f(x)$ is $0$.

Question :  Let $$f\ :\ [a,b]\rightarrow \mathbb R$$   be  continuous . And  there  exist  constants  $\alpha$  $\beta$  such  that  $\forall c\in [a,b]$  $$\alpha \int_a^c f(x)dx +\beta \int_c^b f(x)dx =0 $$   Prove  that  $f=0$  allover  $[a,b]$.  Attempt :(not much useful )   Since  the  equation  holds  for  all  $c\in [a,b]$   , if  take  $c=a$  then  we  have $$\beta \int_a^b f(x)dx =0 $$  And  taking  $c=b$  we  get $$\alpha \int_a^b f(x)dx=0 $$  See  if  both  $\alpha=0$  and  $\beta=0$  hold  then  there  is  nothing  to  do . If  only  one  of  them  is  $0$   and  the  other  is  non-zero  then  from  the  last  two  equations  we  get $$\int_a^b f(x)dx =0 $$ and  this  does   not  ensure   $f$'s  being  identically  $0$  on  $[a,b]$ (for  example : $f(x)=sin x$  and $a=0$,$b=2\pi $ ) .   So  our  only  possibility  is  that  both $\alpha \neq 0$  and $\beta \neq 0$  must  hold .  Now  I  cannot  proceed  any  further  from  this  point . Please  give  me  some   hints  as  to  what  to  do  next .  Thaanks.


Is there a way to make the desktop email notification for Outlook 2013 in Windows 7 stay on longer than 30 seconds? In previous versions the registry could be changed to make it stay on for days. This doesn't work on 2013/WIN 7.

When I receive a new email, the desktop notification pops up and then fade away after 5 seconds. I found how to fix it through changing registry for outlook 2010 and older versions but it does not work with outlook 2013. Does anybody know how to fix it? I need the notification to stay for a desired time.


I downloaded the launcher (from www.minecraft.net) after purchasing and registering. I run windows 7 ultimate (YES, i downloaded the windows .exe version). I start the launcher and it works fine. I sign in, works fine. I hit play, and all seems normal, until the Mojang screen pops up. Stays up for maybe 3 or 4 seconds, then it will crash back to the launcher. Does this over and over again. Ive tried re-downloading minecraft, re-installing java, several things. Error log reads as follows:  # # A fatal error has been detected by the Java Runtime Environment: # #   EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x053c3e88, pid=3680, tid=648 # #  JRE version: Java(tm) SE Runtime Environment (7.0_60-b19)  (build 1.7.0_60-b19) #  Java VM: Java HotSpot(tm) client VM (24.60-b09 mixed mode, sharing windows x86 ) #  Problematic frame: #  C  [ig4dev32.dll+0x3e88] # #  Failed to write core dump. Minidumps are not allowed by default on client versions of windows # #  If you would like to submit a bug report, please visit: #    http://bugreport.sun.com/bugreport/crash.jsp #  The crash happened outside the Java Virtual Machine in native code. #  See problematic frame for where to report the bug. #

Unlike when the game crashes it goes to a black screen and then the stack trace. This time the game just closes and leaves a nice hs_err_pid.txt file for us, which you can find .  I've checked around Google and most people's answer is to Update my Graphics card, I have attempted this and the AMD Auto Detect application just tells me that it's up to date.  System: I record with Fraps sometimes but this does not mean that this causes it (it happens when not recording too). I also run Minecraft on a RAMDisk that has 512MB.  Can anyone give me any advice about this?


I would like to force a linebreak, but at the same time I would like to force LaTeX to print at the and of the line, so I would like no space at the and of the line!

I am trying to align some text to left/center/right in the same line. For example, I want to put my phone number on the left, my name in the center, and my email on the right, how do I do that?


I want to have a first level ToC in the beginning of the document, and full ToC at the end. I'm using titletoc.  There's a  but it is actually about printing ToC by parts.  I expected to be able just to call \tableofcontents twice in a document:  \documentclass{article}  \usepackage{titletoc}  \begin{document}  {   \setcounter{tocdepth}{1}   \tableofcontents }  \section{H1} \subsection{H2} \section{H1} \subsection{H2} \section{H1} \subsection{H2}  {   \setcounter{tocdepth}{2}   \tableofcontents }  \end{document}   but it doesn't work.

See the min expl below. I would like to have two ToC: one giving only the rough structure of the document and a second one giving all the details down to subsubsections. The code pasted below should do just that but the second ToC is not displayed which I do not understand.  \documentclass{report}  \begin{document}  \setcounter{tocdepth}{1}           \setcounter{secnumdepth}{3}         \tableofcontents  \renewcommand*\contentsname{Contents (detailed)}  \setcounter{tocdepth}{3}            \tableofcontents  \chapter{XXX} \section{YYY} \subsection{WER} \subsubsection{ABC} \subsubsection{DEF} \subsection{ZTR} \subsubsection{OIU} \subsubsection{OIZ} \subsubsection{POI} \section{YYY} \subsection{WER} \subsubsection{EDC} \subsubsection{RFV} \subsection{TGB} \subsubsection{ZHN} \subsubsection{OUH} \subsubsection{WEK} \chapter{ZZZ} \chapter{AAA}  \end{document}      Just noticed there is still a problem with hyperref:  \documentclass[10pt, a4paper]{report} \usepackage{shorttoc} \usepackage{hyperref} \begin{document}  \setcounter{secnumdepth}{3}        \pdfbookmark[1]{Contents}{toc}     \shorttoc{Contents}{1}   \pdfbookmark[1]{Contents (detailed)}{toc}     \shorttoc{Contents (detailed)}{3}  \tableofcontents  \chapter{XXX} \section{YYY} \subsection{WER} \subsubsection{ABC} \subsubsection{DEF} \subsection{ZTR} \subsubsection{OIU} \subsubsection{OIZ} \subsubsection{POI} \section{YYY} \subsection{WER} \subsubsection{EDC} \subsubsection{RFV} \subsection{TGB} \subsubsection{ZHN} \subsubsection{OUH} \subsubsection{WEK} \chapter{ZZZ} \chapter{AAA}  \end{document}    By what does {toc} has to be replaced in the second \pdfbookmark? [Sorry, had problem with editing the above comment --> administrator please delete it!]


I currently have Windows 7 and Linux Mint installed.  When my pc starts up, it shows me the Grub menu, it shows an entry for Mint linux and the windows boot menu.  I am wondering, if i was to install Elementary OS, would it be automatically added to grub or do i have to put some command in the terminal?  I also want to ask, when i boot from my Elementary OS cd, and install it, just before it finishes, it shows some kind of error saying some error about cannot install to grub or something, ive tried installing to a separate partition and alongside "Them", but had no luck.  I'm really new to Linux, and want to keep my Mint Linux and Windows 7 because i have files on them

I currently have Windows 7 and Linux Mint installed.  When my PC starts up, it shows me the Grub menu, it shows an entry for Mint Linux and the Windows boot menu.  I am wondering, if I was to install Elementary OS, would it be automatically added to grub or do I have to put some command in the terminal?  I also want to ask, when I boot from my Elementary OS cd, and install it, just before it finishes, it shows some kind of error saying some error about cannot install to grub or something, I've tried installing to a separate partition and alongside "Them", but had no luck.  I'm really new to Linux, and want to keep my Mint Linux and Windows 7 because I have files on them.


Let $\mathbb{Q}[\alpha]=\{g(\alpha); g\in  \mathbb{Q}[X]\}$ be a field extension of the rational numbers. The field extension $\mathbb{Q}[\alpha]$ is the smallest possible subring of $\mathbb{C}$ containing the element $\alpha$ and the rational numbers. It can be seen by using the undamental theorem on homomorphisms that $\mathbb{Q}[\alpha]$ is even a field itself.   While I understand the proof using the homomorphism  theorem, and see that $\mathbb{Q}[\alpha]$ is a ring, I can't see why it satisfies the inverse element (for multiplication) condition needed to be a field.  In general $g(\alpha)$ can be something like $g(\alpha)=\sum_{i=0}^\infty c_i\alpha^i, c_i\in \mathbb{Q}$. So how would I construct the inverse element, for example to $\alpha$? I can only do it for the addition but not for multiplication.

If $K$ and $k$ are fields, $K\supset k$ is a field extension and $\alpha \in K$ is algebraic over $k$, then we denote by $k[\alpha]$ the set of elements of $K$ which can be obtained as polynomial expressions of $\alpha$.   $$k[\alpha] = \left\{P(\alpha): \quad P\in k[X]  \right\} $$  Also, we denote by $k(\alpha)$ the smallest subfield of $K$ containing both $k$ and $\{\alpha\}$. This is easily seen to be equal to the set of fractions of polynomial expressions in $\alpha$ (just thinking about the way the "smallest" subfield must be generated):  $$k(\alpha) = \left\{\dfrac{P(\alpha)}{Q(\alpha)}: \quad P,Q\in k[X] \text{  and } Q(\alpha)\neq 0 \right\} $$  If $M$ is the minimal polynomial of $\alpha$, it is easily shown that $k[\alpha]\simeq k[X]/\langle M\rangle$ is a field  and therefore a subfield of $k(\alpha)$ containing both $k$ and $\{\alpha\}$. Therefore $k(\alpha)=k[\alpha]$, because $k(\alpha)$ is the smallest.   It follows that all quotients $\dfrac{P(\alpha)}{Q(\alpha)}$ are equal to $H(\alpha)$ for some polynomial $H\in k[X]$.   What I want to see is a more direct proof of this fact. Given $P$ and $Q$, how do you produce this $H$?


I pretty much want to make a main site that's a proper site, then a subdomain (I think that's what it's called) so I can also make a thing where you go through the folders (the "Index of /folder/folder/file" thing (don't know the proper name).  Sorry for the horrible explanation.

I have a server at mysite.no-ip.org. Everything is working fine and I have a blog and owncloud that I access writing mysite.no-ip.org/blog and mysite.no-ip.org/owncloud. Now, I want to create subdomains so that I can write blog.mysite.no-ip.org and owncloud.mysite.no-ip.org.  I have looked a lot into it and the simplest tutorial was this one which I followed.   Except that I am not on my server but ssh into it remotely so if I use localhost I cannot see if this works I believe. This is my first obstacle, can I follow this tutorial without being present next to the server?  I also just discovered CNAME records which (I am not completely sure) seem necessary to what I want to do. I use no-ip.org and I have tried to follow something like this but this is not really clear either   Does anyone have any pointers? This is quite shady to me and I have no idea if I am far from the solution or really close (at least if I could try localhost that would be a first step in order to check my Apache conf but I can't even do it since I ssh).  Anyways, thanks for your help in advance. Any help, link is welcomed.


I'm close to capacity on this Windows 10 laptop and would like to reduce my biggest users.  Office 365 is the largest as you can see.  I only need Word and Excel.

I just started the Office 2016 Setup/Installation on my Windows 10 PC. The installation worked fine and started automatically showing only this dialog:    But there are no additional settings possible! I need to choose which programs I want to install and also add additional tools that are often missing when doing a default installation.  How can I change the Office Installation Settings?   Choose programs to install Add/Remove Office Tools (Maybe) Office installation directory   When I check after the installation in the the windows settings, the Office can only be uninstalled - no modifications available:


I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


I would like to know how to display a custom pagination in search results. By default drupal search is displaying 10 results but no pagination even $pager; is printed in search-results.tpl.php. I know this question is asked many times but I did not find the answer. Is there any hook implementation for custom pagination?

I have a code, that outputs a standard pager:  print theme('pager');   it outputs this:
Pages

1

2

3

next ›

last »

   How can I change the HTML to something like this:

&lt;

1

2

3

&gt;

   I looked into this thread: , created a function bartik_preprocess_custom_pager and a file custom-pager.tpl.php inside my Bartic theme templates, but I can't make it work.  print theme('custom_pager');   outputs nothing. Does anybody know, how can I customize the HTML output for a pager, creating one just for 1 page?


Let  $G(V,E)$ be a simple directed graph such that  • for each pair of vertices $u\neq v$, exactly one of the two edges $(u,v)$ or $(v,u)$ is in $E$  Prove that there is a vertex $s \in V$ such that for all vertex $v\neq s$,   • either $(s,v) \in E$,  • or there exists  $u \in V$ such that  $(s,u) \in E $and$ (u,v) \in E.$  I don't know how to prove it please give me some help to prove it.

Can you prove via induction that there exists a node in a directed graph of n nodes that can be reached in at most two edges from every other node in the graph. Every node in the graph is required to have an edge with every other node that either points out or in (For every pair of nodes X and Y, either X points to Y or Y points to X).


How to create executable file of c or cpp program which can be open by double click in ubuntu ??

I read somewhere that I need to install 'build essential packager' & so I tried:  sudo apt-get install build-essential  Reading package lists... Done Building dependency tree        Reading state information... Done build-essential is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   But the file still wont compile or run...  gcc -Wall -W -Werror factorial.cpp -o factorial.   gives me:   gcc -Wall -W -Werror factorial.cpp -o factorial. factorial.cpp:3:22: fatal error: iostream.h: No such file or directory compilation terminated   This is my piece of code: //WAP to demonstrate static member for calculating factorial      #include<iostream.h>         #include<conio.h> class fact { int i;     static int count;     public :      void calculate()     {         long int fact1=1;         count++;         for(i=0;i<=count;i++)         {             fact1=fact1*i;         }         cout<<"\nFactorial of"<<count<<"="<<fact1<<"\n";     } }; int fact :: count; void main() {     int i;     clrscr();     fact f;     for(i=1;i<=15;i++)     {         f.calculate();     }     getch(); }   What shoud I do..???


I've this RC filter circuit (r is connect to earth on the bottom):    My Vin is a square wave:    With Laplace transform I derived that:  $$Vout(s)=\frac{r}{r+\frac{1}{cs}}\cdot Vin(s)$$  and this square wave has a laplace transform of $$Vin(s)=\frac{\text{A}\tanh\left(\frac{\text{T}s}{4}\right)}{s}$$  My math (H(x) is the heaviside-stepfunction):    So, when we substitute that in,in the equation for Vout(s) and calculate the inverse laplace transform, and plot that function I got this:       Q: Why do I get (from the theory) this strange output voltage? I choose T=1/50 (so the frequency is 50 Hz) and A=6 and R=1980ohm and C=4.7microfarad   EDIT:  When I make A=-6 and remove the 'floor'part I got this:

I've this RC filter circuit (r is connect to earth on the bottom):    My Vin is a square wave:    With Laplace transform I derived that:  $$Vout(s)=\frac{r}{r+\frac{1}{cs}}\cdot Vin(s)$$  and this square wave has a laplace transform of $$Vin(s)=\frac{\text{A}\tanh\left(\frac{\text{T}s}{4}\right)}{s}$$  So, when we substitute that in,in the equation for Vout(s) and calculate the inverse laplace transform, and plot that function I got this:       Q: Why do I get (from the theory) this strange output voltage?


Let $f:[0,1] \to [1,2]$, continuous on $[0,1]$ with $1<f(1)<2$. Show that $$\int_0^1\left (f^2(x)-2f(x)\right )\, dx>-1.$$ We have that $$(f(x)-1)^2\geq 0\implies \int_0^1 (f(x)-1)^2\, dx\geq 0 \Rightarrow \int_0^1\left (f^2(x)-2f(x)\right )\, dx\geq -1.$$ Till here we have $\geq$ instead of $>$. How can we show that the equality doesn't occur? Does the same holds also if $f$ is Riemann integrable?

Suppose $f$ is continuous, $f(x) \ge 0$ on $[a,b]$ and $\int_a^b f(x) dx=0$. Show that $f(x)=0$ on $[a,b]$.   I know that if $f$ in continuous at $x_0$ and $f(x_0) > 0$, then there exists $\delta > 0$ s.t. $f(x) \ge \frac{1}{2} f(x_0)$ for $|x-x_0| < \delta$ and I think it should help me but I'm stuck at this point.


I was trying to play this morning, when I open Pokemon go app, it ask me to confirm my gmail account so I ask to receive 6 number pin on my mobile by message. As soon as I confirmed it, it start from 0, chose your Pokemon,etc. what can I do to have back my account? I was already at level 15. I just use my mobile to play, I don't use any other device, and nobody else use my mobile. I didn't cheat. I start playing in London, I came to Madeira island in holiday's and I will be back to London in 6 days. Thank you very much for your attention.  I've tryed many things to fix it, but nothing. I try to start again choose the same name but it says not available. Does it mean I still have the chance to recover my account?

I just updated the Pokemon go app and it asked me to log in again and I'm back at the very start, please help!