If cryptographic hashes are completely unique, could they theoretically be used to transfer data?

I know it sounds ridiculous, but hear me out. We know that good hashing algorithms would generate hashes that are pretty much unique. If, in the future, we create a perfect (or just really near perfect) algorithm, could those hashes be used to represent larger chunks of data in a totally unique way? If they truly were unique and determined entirely by the file, could a powerful enough machine work backwards and reconstruct the file?  Now, this is a bit of a stretch from what we currently know, but I'd think it might be possible. Quantum computers can perform many different tasks at once, and we know that they pose a significant threat to modern forms of encryption because of this ability. While that isn't exactly the same thing as guessing every possible file that could've produced a particular hash, but I'd imagine there might be a way to make the process more efficient.  Maybe you get a hash that's a couple kilobytes long, allowing for billions of different input types. Combine that with a computer capable of generating and testing every possible input simultaneously and you'd be able to send tons of information in a couple kilobytes of transmission.  I'm not asking if it's possible to do with our current technology, as I'm fairly sure it isn't. I just want to know if the process of hashing a file could (in theory) support it.


Cast a quickened spell as a standard action

As a prepared caster, are you able to cast a quickened spell using a standard action instead of a swift action? I know a move action is not allowed to be converted into a swift action.


The number of badges (the x insert_number_here) is usually aligned properly with the corresponding badge name. Now it is offset, being a little too low as seen in this screenshot:  Can we fix this and raise the number of badges a little higher so it is aligned with the badge?


macOS Sierra How do disable Siri prompt?

After upgrading my wife's iMac to macOS Sierra 10.12.0, she chose to disable Siri from the System Preferences for her own reasons. Now, every time we press the play/pause button on one of the , the following dialog appears:    Is there a way to prevent this from displaying, even if it means somehow nuking Siri altogether?


If I want to estimate $E_P(f (x))$ where f is some function, I can produce samples $\left\lbrace x^{1} , \dotsc , x^{L}\right\rbrace$ from the Markov chain (with a stationary distribution matching $P$ ) and have the following estimator:  $$E_{MCMC} (f (x)) = \frac{1}{L} \sum_{l=1}^{L} f \left(x^{l} \right).$$  The samples produced by MCMC are non-i.i.d.. It is common to analyze the effective sample size (ESS) of an MCMC sampler, i.e.,   How should I find the ratio of the sample of size $S$ produced by MCMC to its effective size (the ratio between number of samples produced by the chain to the number of perfect i.i.d. samples both of result into estimators that have same variance)?


Any word for this habit defined in following sentence?

If one do his assigned work always, and correctly. is there any single word for this habit?


How can I shutdown my Android phone using an adb command?

How do I halt an android phone using adb command? I can reboot, but I don't know how to halt.  I tried shutdown -k wait command, but it did not work.


Windows 7+ Recent Places is not sorted by date

Recent Places is a great feature in Windows 7 and up, but it's frustrating to me that it's always sorted in alphabetical order on the folder name. The result is that the most recent place isn't at the top. When I access Recent Places in an application such as Word, I have to click the date column (every time) to make it re-sort the list of folders.  How can I set it so that the contents of Recent Places is always sorted by order of most recent folder first?


Get warnings for breaking of inline math

I have read  about how to prevent line breaking in inline math. Now I wonder if it is possible to get a warning to the log for every breaking of an inline math formula.


We want to find the $[\Bbb{Q}(\sqrt2+\sqrt3)(\sqrt5):\Bbb{Q}(\sqrt2+\sqrt3)]$.  My first thought is to find the minimal polynomial of $\sqrt5$ over $\Bbb{Q}(\sqrt2+\sqrt3)$. And from this, to say that $[\Bbb{Q}(\sqrt2+\sqrt3)(\sqrt5):\Bbb{Q}(\sqrt2+\sqrt3)]=\deg m_{\sqrt5,\Bbb{Q}(\sqrt2+\sqrt3)}(x).$  We take the polynomial $m(x)=x^2-5\in\Bbb{Q}(\sqrt2+\sqrt3)[x].$ This is a monic polynomial which has $\sqrt5\in \Bbb{R}$ as a root. We have to show that this is irreducible over $\Bbb{Q}(\sqrt2+\sqrt3)$, in order to say that $m(x)=m_{\sqrt5,\Bbb{Q}(\sqrt2+\sqrt3)}(x)$. The roots of $m(x)$ are $\pm \sqrt5\in \Bbb{R}.$ So,  $$m(x) \text{ is irreducible over } \Bbb{Q}(\sqrt2+\sqrt3) \iff \pm \sqrt5 \notin \Bbb{Q}(\sqrt2+\sqrt3)=\Bbb{Q}(\sqrt2,\sqrt3)$$  because $\deg m(x) =2.$   And this is the point I stack. I tried with the use of the basis of the $\Bbb{Q}$-vector space $\Bbb{Q}(\sqrt2+\sqrt3)$: $$A:=  \{1,\sqrt2,\sqrt3,\sqrt6 \}$$   in order to claim that $\nexists a,b,c,d\in \Bbb{Q}:\sqrt5=a+b\sqrt2+c\sqrt3+d\sqrt6$ but this doesn't help.  Any ideas please?   Thank you in advance.


I'm using the graphics package and I can insert my graphic into the document without any difficulty, apart from the fact that it's huge!  I am using the following command:  \documentclass{article}  \usepackage{graphics}    \begin{document}    \begin{figure}[b]    \centering    \includegraphics{cinema}    \caption{Fig. 1: Simple Past}   \end{figure}  \end{document}   But when I insert the scaling option: [scale=0.75] etc. It won't work and I get the message   Runaway argument? scale=0.75]{cinema} \caption {Fig. 1: Simple Past} \end {figure}  ! Paragraph ended before \Gin@iii was complete. <to be read again>                     \par


Does the variance of a sum equal a double sum of covariances?

Say I have a collection of $n$ random variables $X_i$ that don't necessarily have any special properties like independence or identical distribution.  Is it true in general that $\text{Var}\left(\sum_{i=1}^n a_iX_i\right)=\sum_{i=1}^n\sum_{j=1}^n a_ia_j\text{Cov}\left(X_i,X_j\right)$, where the $a_i$ are constants?  I got to that equation by looking at the formula $\text{Var}\left(aX+bY\right)=a^2\text{Var}\left(X\right)+b^2\text{Var}\left(Y\right)+ab\text{Cov}\left(X,Y\right)$, viewing variance as a special case of covariance, and thinking about adding successively more variables.  If so, it looks like I could calculate the variance of a sum of random variables by adding up all the elements in their variance-covariance matrix--which would be interesting, since the combination of random variables itself is just a one-dimensional thing.  I think it clearly holds in the two-variable case, but I didn't find any discussion on the topic in the case of $n$ variables.


Probablity of drawing all the red balls while blue and green are still left

Suppose that a box contains 10 red balls, 20 green balls, and 30 blue balls.   Suppose also that balls are drawn from the box one at a time at random.  What is the probability that all the red balls are drawn before the blue or green balls are themselves exhausted. What is the probability that as the last red ball is drawn, there remains at least one blue and one green left in the box.  The answer I was given is $\dfrac{7}{12}$ and a general equation is: $$ \dfrac{b g}{1-b}+\dfrac{b g}{1-g} $$ where $$ g=\dfrac{20}{60},b=\dfrac{30}{60} $$ but why?


Let $a$ and $b$ be positive integers such that $ab+1$ divides $a^2+b^2$.  Show that $\frac{a^2+b^2}{ab+1}$ is the square of an integer.


Windows 10 default programs keep changing

Since the fall update last month, Windows 10 automatically keeps changing the default apps for certain types (mostly browser,pdf,mp3,jpg). I have tried changing them back from the Settings app as well as the Control Panel.  I have observed that this happens mostly while unzipping files using WinZip. Windows changes the default programs back to Microsoft recommended programs such as Edge, Photos, Groove etc.  Is there a way to restrict this from happening? Has anybody else encountered a similar situation? I couldn't find similar question anywhere so I'm asking this here.


If $A$, $B$ and $C$ are the angles of a triangle then find the value of $\Delta$

I'll state the question from my book below:     If $A$, $B$ and $C$ are the angles of a triangle, then find the determinant value of   $$\Delta = \begin{vmatrix}\sin^2A & \cot A & 1 \\ \sin^2B & \cot B & 1 \\ \sin^2C & \cot C & 1\end{vmatrix}.$$   Here's how I tried solving the problem:  $\Delta = \begin{vmatrix}\sin^2A & \cot A & 1 \\ \sin^2B & \cot B & 1 \\ \sin^2C & \cot C & 1\end{vmatrix}$  $R_2 \to R_2 - R_1$  $R_3 \to R_3 -R_1$  $= \begin{vmatrix}\sin^2A & \cot A & 1 \\ \sin^2B-\sin^2A & \cot B-\cot A & 0 \\ \sin^2C-\sin^2A & \cot C-\cot A & 0\end{vmatrix}$  Expanding the determinant along $C_3$  \begin{align} &= (\sin^2B-\sin^2A)(\cot C-\cot A)-(\cot B-\cot A)(\sin^2C-\sin^2A)  \\ &= \sin(B+A) \sin(B-A) \left[\frac {\cos C}{\sin C} - \frac {\cos A}{\sin A}\right] - \left[\frac {\cos B}{\sin B} - \frac {\cos A}{\sin A}\right]\sin(C+A) \sin(C-A)  \\ &= \frac {\sin(B+A) \sin(B-A) \sin(A-C)} {\cos A \cos C} - \frac {\sin(A-B) \sin(C+A) \sin(C-A)} {\cos A \cos C}  \\ &= \frac {\sin(B-A) \sin (A-C)} {\cos A} \left[\frac {\sin(A+B)} {\cos C} - \frac {\sin(A+C)} {\cos B}\right]  \\ &= \frac {\sin(B-A) \sin (A-C)} {\cos A} \left[\frac {\sin C} {\cos C} - \frac {\sin B} {\cos B}\right]  \\ &= \frac {\sin(B-A) \sin (A-C) \sin (C-B)} {\cos A \cos B \cos C} \end{align}  I tried solving further but the expression just got complicated. I don't even know if the work I've done above is helpful. My textbook gives the answer as $0$. I don't have any clue about getting the answer. Any help would be appreciated.


Let $a$ and $b$ be positive real numbers. Prove that $$(a+b)^3\le 4(a^3+b^3)$$  My work and thoughts: I've tried the brutal math resulting in: $a^2b+ab^2\le a^3 +b^3$ and not sure where to go from there. Or it can be seen as  $a^2b+ab^2\le(a+b)(a^2-ab+b^2).$ Any thoughts, special inequalities, or different methods to help out?


Can we say "I come not" or use "not" after verbs  like that sentence in English ?


"Add" button doesn't work with JavaScript off

I'm using stackoverflow.com with JavaScript off. I accept this comes with somewhat less functionality, however for the most part SO works fine.  If I look at the home page (), every single button on there except for two types works with JS off.  The first second is that the "x Votes; y answers;z views" mouse-over indicates they're links but clicking them does nothing. This one is less of an issue because the user can still click the question title, and they're only implied buttons anyway.  The second (and bigger) issue is the "Add" buttons next to "Favorite Tags" and "Ignored Tags". These are explicit buttons that don't do anything with JS off. There is no working JS substitute for them (the "tag subscriptions" link itself works, but the page it goes to doesn't work with JS off, but that's another bug report).


using custom styling in lwc for lightning components

I'm trying to follow this document  to create an accordion section that resembles a page layout. This is the code:  <template>     <lightning-card  title="Hello">
{activeSectionsMessage}
         <lightning-accordion allow-multiple-sections-open                                 onsectiontoggle={handleSectionToggle}                                 active-section-name={activeSections}>         <lightning-accordion-section name="A" label="Accordion Title A">
This is the content area for section A.

Donec vitae tellus egestas, faucibus ipsum ac, imperdiet erat. Nam venenatis non ante at sagittis. Integer vel purus eget nunc semper placerat. Nam tristique quam leo, et posuere enim condimentum quis. Ut sagittis libero id lectus tempor maximus. Nunc ut tincidunt eros, a hendrerit leo. Suspendisse quis fermentum dolor. Nulla euismod consectetur leo, id condimentum nunc consequat quis.
             </lightning-accordion-section>              <lightning-accordion-section name="B" label="Accordion Title B">
This is the content area for section B.

Nam at elit et justo scelerisque ullamcorper vel a felis. Mauris sit amet lorem sed est sagittis blandit nec ac turpis. Ut a mi id turpis pharetra ornare. Nullam rhoncus feugiat nunc, ac pulvinar felis pulvinar at. Nullam efficitur aliquet justo et ultricies. Maecenas eu felis aliquam, tincidunt elit at, suscipit leo. Duis ut urna nec nibh hendrerit lacinia. Sed non auctor libero. Sed pellentesque tempor mollis.
             </lightning-accordion-section>              <lightning-accordion-section name="C" label="Accordion Title C">
This is the content area for section C.

Nulla ornare ipsum felis, vel aliquet dui blandit vel. Integer accumsan velit quis mauris pharetra, nec sollicitudin dui eleifend. Cras condimentum odio mi, nec ullamcorper arcu ullamcorper sed. Proin massa arcu, rutrum a ullamcorper nec, hendrerit in sem. Etiam tempus eros ut lorem tincidunt, id condimentum nulla molestie. Morbi hendrerit elit pretium, ultrices neque non, ullamcorper justo. Quisque vel nisi eget eros efficitur semper. Nulla pulvinar venenatis quam vitae efficitur. Nam facilisis sollicitudin quam ac imperdiet.
             </lightning-accordion-section>         </lightning-accordion>     </lightning-card> </template>   Result:   I want to change the color of the title "Accordion Title A/B/C" to be grey, exactly like in a page layout.  i don't understand what i am missing but i cant change the background of it.  i simply tried to do  .slds-accordion__summary {     color: red; }   without success.


I'm using this script to catch posts from a custom post type  $paged = ( get_query_var('paged') ) ? get_query_var('paged') : 1; $args = array(           'post_status' => array('publish', 'future'),           'post_type' => 'evento',           'orderby' => 'date',           'order' => 'DESC',           'posts_per_page' => 9,           'paged' => $paged      );   If I set Settings >> Reading >> Blog pages show at most to 6, site return 404 on the second page. If I set to 5, works fine. Why it happens?  I'm using roots theme.


What does the complex electric field show?

We have a complex electric field. Is there any definition for absolute and imaginary part of a complex electric field? What do they stand for?


Is bringing tea from coca leaves to Europe illegal?

When travelling in Chile, tea from coca leaves was something you could buy at regular places. It is even sold as a preventive to altitude sickness in places like San Pedro de Atacama. After feeling the horrible effects of altitude sickness, I did try Mate di Coca before going on my next to the higher altiplanos. Whether it as a placebo or not, it seemed to work. I was considering buying a package of coca tea to bring back as souvenir, but I hesitate since I didn't know if it would be considered legal. Google provided mixed answers. From a big no, to a maybe in some countries, to yes because you can't make cocaine out of tea from coca leaves.  What is factual? Can you bring Mate de Coca as a souvenir?


Integer valued solution to equation $x^2+y^2+1=xyz$

The question goes like this: For $x,y,z\in\mathbb{N}$, $x^2+y^2+1=xyz$.  Prove $z = 3$.  How do I even start?


Let A,B be in $M_{mxn}(\mathbb{R})$  Prove that if rank(A + B) = rank(A) + rank(B), then col(A) ∩ col(B) = {0}  I started with a proof by contradiction, since we know that rank(A + B) ≤ rank(A) + rank(B). I assume that if rank(A + B) < rank(A) + rank(B), then col(A) ∩ col(B) = {0}. I realize that we don't have to do the > case. However I am a little confused on how to show col from rank.


Find the value of $\cos(2\pi /5)$ using radicals

This is homework so if there is another example that can illustrate the technique I would happily accept that as guidance. The only thing I have been able to find is a question asking about $\cos(2\pi/7)$, which I think is a much harder problem.  I dont have the faintest idea how to solve this and the textbook (Hungerford) doesn't have any examples at all. Ive tried looking for resources online but havent found any that I was able to understand.  So can anyone show me how to solve these types of problems? Thanks a bunch.


Fantasy/sci-fi cartoon with 4 "guardian" characters with animals determining their powers, one merges with his animal into a monster

I don’t remember much about it but it was like a system where the children all inherit their powers from their parents. They were all guardians and had a special animal/dinosaur as a pet that determined their powers.  One was a guy who I think had rocks/lava power. He had dark hair. He eventually turned sort of evil at the end because he believed he was a monster due to permanently merging with his “animal” and couldn’t switch back to human form. One was a girl that was ice power had white hair and wore blue. Her “animal” was a flying tiny dinosaur The others were a brother and sister, the sister couldn’t walk so the brother always worried about her but she was super strong I think.


I got captcha verification about picking up certain images from list. I did so and got some text to copy and paste in a new box. I pasted it, but there is no button to submit the same. I looked everywhere, but it was not there. When I press enter, it just adds new line but nothing else happens.  Wondering if any of my extensions is blocking it, see the screenshot, I have disconnect and privacybadger installed, but it dont have anything blocked from google other than google analytics.


No version of Ubuntu can be installed with any Skylake 6th generation Intel processor

Ubuntu can't be installed on my system because of what the title says. This is because support Intel HD Graphics 530 was only just added in Linux kernel 4.3 and all versions of Ubuntu only have kernel versions up to 4.2 as of 15.10. My computer's processor is the new Intel Skylake 6600K if you need to know, everything else is generic. It has a UEFI BIOS motherboard. Help?


How to set the monitor to its native resolution which is not listed in the resolutions list?

After installing Ubuntu 10.04 with my Samsung SyncMaster B2030, native resolution (1600X900) is not found in the list of resolutions.


For a dataset I ran a random forest model with sikit learn. When I checked important variables from RF , I was unable to understand the reason for choosing that variable as important.  In my understanding There would be rules for the tree built by RF. Is there a way to visualize the trees and understand the rules. Or how can I know the reason on choosing that variable as important by RF


Several badge descriptions contain raw HTML

I was reading through some badge descriptions and noticed that Synonymizer's description needs to be updated. As it stands, there is raw HTML (an href) in the description:    EDIT: after reading comments by @ColeJohnson, I have come to the understanding that this post comes off as whiny. I want to make it very clear that I wasn't ever trying to complain. My first reaction was to fix the perceived error myself. When I realized I was unable to do so, I figured the best course of action would be to find someone who would be able to make the necessary edits. Hence the post here.


What are the advantages of using a  instead using ?  I usually get the elapsed time using the following mechanism:  int ini = Environment.TickCount // perform some operations int elapsedMilliseconds = Environment.TickCount - ini;   But some SO experts recommended using an StopWatch:  StopWatch sw = new StopWatch(); sw.Start(); // perform some operations sw.Stop(); int elapsedMilliseconds = sw.EllpasedMillseconds;   Is just a OOP thing, or maybe I'm measuring the elapsed time in a wrong way?


I'm in little trouble. The problem is when I'm trying to compare 2 strings(type String) operator '==' returns FALSE, but actually strings are equal. Here's the code with its problem:  //before the following code I filled the "LinkedList <String> command" and there is //a node with value of args[0] String deal=""; Iterator it = commands.listIterator(); if(it.hasNext() == true) {     if(it.next() == args[0])     {         deal += it.next();         it.hasNext();         break;     } }   Thank You!!!


All possible combinations of a set as a list of strings

I am trying to write a function in Python  def all_strings(alpha,length):     # ...   which takes a given alphabet (alpha) and a length and returns all possible combinations of the alphabet restricted by the given length.  For example:  all_strings({0,1}, 3)   should return:  ['000', '001', '010', '011', '100', '101', '110', '111']   I tried looping through the set but you cannot iterate through a set in python. I also considered itertools however permutations and combinations do not allow repetition of numbers.


When did the red shirt careers change to yellow shirts in Star Trek and why?

In the original Star Trek engineers and security officers wore red shirts but in ST:TNG engineers and security officers wore yellow shirts and command officers wore red shirts.  Was it ever explained why there was a uniform color change?


Can you define linear maps between vector spaces over different fields?

My book defines linear maps between vector spaces with a chosen fixed field but can you define linear maps between vector spaces over different fields? Is there any reason to restrict attention to fixed fields?


How can I prevent inline math formulas from overflowing into the margin?

When I compile my document in LaTeX, some formulas in the document in math mode, between $ $, go into the right margin area beyond all the text.  Is there a way to fix this aesthetic problem?


G-rated word lists in various languages for programming children's games

I'm programming a word guessing game that uses large lists of words (no definitions, just words). Word length is configurable. Parents could set the word length to be very short and let small children play the game. I'd like to make sure there are no obviously obscene words in the list. For American English, the closest I've found was a Scrabble-like dictionary file that uniformly labelled questionable words with "obscene" so I can easily filter them out. Does anyone know of a better list in English, and/or any lists in other languages?


I got this question for homework..   Let $\{E_{\alpha}\}$ be a family of connected subsets of a metric space $X$ such that any two of them have a non-empty intersection: $E_{\alpha} \cap E_{\beta}\ne \emptyset$. Prove that the union $\cup_{\alpha}E_{\alpha}$ is connected.  I'm relatively new to the concept of connected sets. I know that a set is connected iff it is the union of 2 separated sets and that one of the two sets are empty.  I don't understand how the fact that some of these sets share elements have anything to do with the union of all these sets...   Please help!  Thanks


How to change extension of all files in a directory?

There are some extensionless files in current directory (there are not dot in their names).  I want to rename like so:  filename -> filename.md   I tried doing mv * *.md but that didn't help.  I am interested in a function that takes an argument for the extension and renames accordingly, and the another one for the files to perform operation on.


I am trying to make a pair of eyeglasses but am having trouble with the lenses. I can't seem to make the lenses look right. I tried using the glass shader but it made the lenses look more like a mirror. I also tried the transparent shader but it just made the lenses invisible. How can I make a material that looks just like a glasses lens?


Is it unwise to contact the professor directly before getting admitted to a program in US?

In his answer of , aeismail says     If the program in question is in the US, for instance, you should probably never contact the professor directly until after you've been admitted into the program in question. Since admissions decisions are handled centrally, it's just a waste of time.   Now I'm surprised with this, and I think I'm not the only one. For many times, not only in this site, but also in real-life examples in my university, I have seen that my friends get accepted through contacting professors beforehand, and those professors are helpful and willing to get you through the adcom. Recall it back, they don't go to US, but I don't think US should be an exception.  Why is it an exception? Why do the "admissions decisions are handled centrally", unlike other universities in the world, where the weight of the professors is heavier? Isn't that sorting the applications by score not good as checking their ability directly through interview? And who is the most suitable interviewer, if not the one who will advise you in the future?


80's sci-fi story/novel with hidden DNA code, alien-caused ice age

I read this sci-fi story, which I think was a standalone novel, in the late 1980's - and I don't think it was all that old then. The main character was solitary, at the start of story foraging in a snowed-under grocery store. His name may or may not be Starkman or Starmann; I seem to recall that his eyes were an unusual colour, maybe yellow or amber. The plot involved his DNA containing some kind of hidden message or instructions, put in his ancestor(s) many thousands of years earlier by a (crashed?) alien scientist. Now, others ("bad guys") are looking for it, creating an artificial ice age (via a dust cloud between Earth and the sun, if memory serves) to drive humans to the equator, where they "help" with humanitarian efforts while actually looking for this DNA code. I read a ton of sci-fi stuff back then, so I may be getting things mixed up after this long, but the main plot is right. I'm in Canada, if that helps/matters.


How can I see my progress towards the socratic badge?

I am pretty sure I've asked questions on 100 days at Christainity.SE, and since I have the silver "Inquisitive" badge, I'm pretty sure my question quality is good.  And yet, I don't have the Socratic badge.  How can I see what my question score is, and the number of days I've asked questions, preferably without having to use the data explorer or the API?


Easy way to install a .deb package without aptitude or synaptic?

I keep trying to install programs, by simply downloading the program, and clicking on it, but I see things are not that simple. Has anyone come up with a simple way to install different programs, without having to rely on Synaptic or Aptitude?  Example: I tried to install a .deb package. Went to the site, downloaded the package, opened up the command line (after making the file executable), the errors began. First there was a dependency file that was required, then there was a public key that was needed, man can someone make this a little bit simpler for a newbie. I think a newbie spends half of his time searching google to figure out how to make things work on Linux. Someone please help make this more simple? Tanks


Download a file using URL in WPF Application without opening browser

Is it possible to download a file using the download link URL using C# WPF Application without opening the browser?  For example: The link -  when typed into the address bar of the browser automatically downloads a file. How can i download this file upon a button click in WPF application (C#) without opening the browser?   TIA.


I have a class that I want to call its methods using just strings. How do I do that?  class MyClass:     def do_something():         print 'MyClass did something'  MyClass.get_method('do_something')()


I want to apply for Schengen visa, but employer NOC which is mandatory document for visa is not available with me

I have resigned from my current company and will be joining a new company soon.   Hence, I cannot get a leave approval letter from my current company, and if I decide to join a new company and then request a NOC (No Objection Certificate) it will be late for visa process completion because of my traveling dates.   What can I show to the embassy as an alternative to this NOC document?


I got a 64195 error in memtest. What should I do?

I have a  (59-358263) Laptop (3rd Gen Ci5/ 4GB/ 500GB/ DOS) and running Windows 10 Pro (latest version).  I’m getting blue screen of death (BSOD) a lot, mainly while gaming so I ran memtest.  I have  of the issue of which might help you recognize the problem.


How to ask user String input until user is done?

Scanner scan = new Scanner(System.in);         System.out.println("Enter the names of each song in the DJ's playlist: ");         System.out.println("When finished, enter done.");         ArrayList <String> NamesOfSongs = new ArrayList<>();         boolean loop = true;         while(loop)         {             String input = scan.nextLine();             if (input.equals("done"))             {                 break;             }             else             {                  NamesOfSongs.add(scan.nextLine());             }         }         System.out.println(NamesOfSongs);         }   Input strings need to be added to the ArrayList until user enters "done" and the method is finished.  Results in:  (after I enter 3 strings and done TWICE)  Enter the names of each song in the DJ's playlist: When finished, enter done. jjjj kkkkk iiii done done [kkkkk, done]


Before you read this question let it be known that this question has been asked before on this site; however, I find that my situation is slightly different then the others.  I recently was searching for places to stay in Germany and I found an apartment that I wanted to book. It looked nice and it was available for the time I wanted, so I booked it.  On the site it said that payments could only be made in cash for booking this apartment and ultimately the reason I decided to go ahead and book this place was that it stated on booking.com that the host will contact you after booking to handle everything from payments to questions.   Before booking I searched the entire site for the hosts contact information so I could ask further questions about the apartment that I did not see on the booking.com website.  I even google searched for this apartment to see if it was listed anywhere else so I could possibly contact the host before booking. On booking.com it did state that there could be cancelation fees if I do decide to cancel at any point. I am new to booking.com and did not have an account it allowed me to book the property without providing any credit card information and as soon as the booking went through shortly after they provided me with the host's contact info. I asked my question and sure enough I wanted to cancel so I went to hit cancel on booking.com. It told me to ask the host for the process of canceling since there could be cancelation fees, I asked the host if I could cancel.  He sent me a picture of a piece of paper stating a cancelation fee is required.  The host only accepts cash payments.  Am I legally bound to travel to Germany and pay this person now?  I had the apartment booked for under an hour.


Can the sequence of derivatives $\{f^{(k)}(0)\}_{k\geq 1}$ be any sequence?

Let $\{a_{k}\}_{k\geq 1}$ be any sequence of real numbers, must there exist a smooth function $f:]-\epsilon,\epsilon[\rightarrow \mathbb{R}$ (for some positive $\epsilon$) such that for every positive integer $k\geq 1$, we have $f^{(k)}(0)=a_k ?$  Thank you a lot.


How to get bash not to treat [ as a test character when using command substitution?

How can I get unmodified output from $() in bash?  I need to have bash return the results of command substitution (via $(command) or `command`), but bash treats the left square bracket as the test builtin and evaluates the text.   > echo "This shows an IP in brackets [127.0.0.1] when not in the command substitution context." This shows an IP in brackets [127.0.0.1] when not in the command substitution context.  > echo $(echo "This should show an IP in brackets [127.0.0.1] but instead evaluates to '1'.") This should show an IP in brackets 1 but instead evaluates to '1'.  > echo $(echo "The subtle addition of a space causes [127.0.0.1 ] to behave differently.") The subtle addition of a space causes [127.0.0.1 ] to behave differently.   Background  Please note that the use of echo above to provide a minimal example is just that; my ultimate use will be including output from ping or tracert to show the IP of a host as seen by that host (i.e. respecting any hosts entries). In this usage, I have little control over the string being output by the command.  > grep -E "^[^#].*stackoverflow" /c/Windows/System32/drivers/etc/hosts 127.0.0.1 stackoverflow.com  > tracert -h 1 -w 1 stackoverflow.com | awk '/Tracing/' Tracing route to stackoverflow.com [127.0.0.1]  > ping -n 1 -w 1 stackoverflow.com | awk '/Pinging/' Pinging stackoverflow.com [127.0.0.1] with 32 bytes of data:  # Using dig or nslookup would show a real IP rather than the forced IP from the hosts entry. > dig @ns1 +nocmd stackoverflow.com +noall +answer stackoverflow.com.      118     IN      A       151.101.129.69 stackoverflow.com.      118     IN      A       151.101.193.69 stackoverflow.com.      118     IN      A       151.101.1.69 stackoverflow.com.      118     IN      A       151.101.65.69  > echo $(ping -n 1 -w 1 stackoverflow.com | awk '/Pinging/') Pinging stackoverflow.com 1 with 32 bytes of data:  > echo $(ping -n 1 -w 1 stackoverflow.com | awk '/Pinging/ {print $3}') 1  > ping -n 1 -w 1 stackoverflow.com | awk '/Pinging/ {print $3}' [127.0.0.1]


What is the correct formula for gravitational time dilation for a satellite in a circular orbit?

In the Wikipedia article on  I see two formulae for the gravitational time dilation. One contains $\sqrt{1 - r_0/r}$ but the other $\sqrt{1 - 1.5 r_0/r}$. What formula should I use to calculate the time dilation due to gravity inside a satellite? The speed induced time dilation is of course just special relativity.  With the first of these two formulas I can perfectly reproduce the graphs on time dilation as a function of $r$,  I find that the two contributions to time dilation cancel at 1.5 Earth radii, all numbers are OK... But why not the second formula?


$f:\bf S^1 \to \bf R$, there exist uncountably many pairs of distinct points $x$ and $y$ in $\bf S^1$ such that $f(x)=f(y)$? (NBHM-2010)

Let $\bf S^1$ denote the unit circle in the plane $\bf R^2$. True/False ?     For every continuous function $f:\bf S^1 \to \bf R$, there exist uncountably many pairs of distinct points $x$ and $y$ in $\bf S^1$ such that $f(x)=f(y)$   Borsuk-Ulam or by taking the function $g(x)=f(x)-f(-x)$, IVT implies that there exist $x$ such that $f(x)=f(-x)$. But I'm unable to show the existence of uncountably many pairs. I think the fact $RP^1 \cong \bf S^1$ may be helpful. Any ideas?


How to make an example image in LaTeX, a dummy image, a spot holder? I have seen it before, but I can't remember how they would made. It would be nice to be able to use example images - if you should help anyone or you need to question in this community. You might say I could , but I tried - and are obviously too stupid to find anything.  \documentclass[12pt,a4paper]{article} \usepackage[utf8]{inputenc} \usepackage[ngerman, danish]{babel} \usepackage[T1]{fontenc} %\usepackage[]{}  \begin{document}  \iffalse \begin{figure} \includegraphics[scale=1]{•}  \end{figure} \fi  \end{document}   Is it also possible to resize the example image? So I need a usepackage to make an image without including an immage. An placeholder so anyone can try my code without needing images - just needing my tex-code. I hope you understand?  Kind regards!


How can I integrate a 3D model in a photo?

If I have a photograph and I want, for example, to add a 3D model of a character so that it seems that it is standing there in the environment, how can I achieve it? At the same time, keeping the tones and lighting of the photograph, and if possible add shadow on the ground so that it really gives the feeling of standing there.


Continunuity of the generalized primitive

Let $f:I\subset \mathbb R\to \mathbb R$ be a Riemann locally integrable function on the interval $I$. Show that, for a fixed $a\in I$ $$ x\mapsto F(x) =\int_a^x f(t)dt ~~~~ $$  is continuous on $I$. This a claim in Brezis book's page 205 lemma 8.2


Can't specify paper size when loading scrartcl in custom class

By default, my system produces A4 documents. If I want to set the paper size to US Letter, I can pass the letterpaper option to scrartcl:  \documentclass[letterpaper]{scrartcl} \begin{document} Hello, World! \end{document}   But if I create my own class that extends scrartcl, I can't pass the letterpaper option in the class file. E.g., this doesn't work (the resulting document has A4 paper dimensions):  mcve.ltx  \documentclass{mcve} \begin{document} Hello, World! \end{document}   mcve.cls  \NeedsTeXFormat{LaTeX2e} \ProvidesClass{mcve}  \LoadClass[letterpaper]{scrartcl}   This does work if I replace scrartcl with article (although I then also have to load the geometry package in both cases to make the PDF paper size match). Even more interestingly, this also works:  mcve.ltx  \documentclass[letterpaper]{mcve} \begin{document} Hello, World! \end{document}   mcve.cls  \NeedsTeXFormat{LaTeX2e} \ProvidesClass{mcve}  \LoadClassWithOptions{scrartcl}   How can I set the letterpaper option in my class file?


80's 90'sTV series/movie identification, live-action: bad guy turns to be the good one

I remember a sci-fi show/movie as a child where a kid/teen and a generic hero traveled to other planets. One was a mushroom people one, another was a giant people one, can't remember more. They were always followed by a dark red robot/suit. This enemy at some point was revealed to be the real good guy, just when he removed his helm. I think he was a black guy. The whole time, he had been trying to save the kid from the other guy. Then, he helped the kid and fight the false hero. Can't remember more.  If someone know something about this please tell me.


Prove that a group with exactly two proper nontrivial subgroups is isomorphic to $\mathbb{Z}_{pq}$ or $\mathbb{Z}_{p^3}$.

Suppose $G$ is a group and has exactly two nontrivial proper subgroups. Prove that $G$ is cyclic and $|G|=pq$ where p,q are distinct primes or $G$ is cyclic and $|G|=p^3$ where $p$ is a prime. Usually my tactic to show a group is cyclic is find an elements such that its order and order of the group are the same. But here I cannot do so because I have no informatio regarding order of elements. So I stuck. Can anyone help me?


Why are $W$ bosons massless above electroweak scale?

Because of the Higgs mechanism, one must replace the Higgs field $\phi$ with $\phi_0 + \phi_1$ where $\phi_0$ is the vacuum expectation value. As far as I understand, the $\phi_0$ gives the mass term to bosons after developping the product $D_{\mu}\phi D^\mu \phi$. But I don't understand why these mass terms should disappear above the electroweak scale where it is said that the gauge bosons are massless.


When I run update-manager command on terminal, I get this error"  W: The repository 'http://ppa.launchpad.net/colingille/freshlight/ubuntu xenial Release' does not have a Release file. N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use. N: See apt-secure(8) manpage for repository creation and user configuration details. E: Failed to fetch http://ppa.launchpad.net/colingille/freshlight/ubuntu/dists/xenial/main/source/Sources  404  Not Found E: Some index files failed to download. They have been ignored, or old ones used instead.


I have a little PHP script which just needs to get all the rows from a table in a SQLite database.  The name of the table is always something like 174597131028398082-199534472775860224.   This name is composed from two variables (sid and cid) which are defined through the parameters of a GET request. The problem is that instead of returning all the rows (which I would display later in the script), I get this error : SQLSTATE[HY000]: General error: 1 no such table: :sid-:cid.  It seems like PHP does not replace :sid and :cid with the correct values. I've seen  about a similar problem, but I still can't get it working.  Here's my code :  $query = "SELECT * FROM `:sid-:cid`;";  $queryparams = array(     ':sid' => $_GET['sid'],     ':cid' => $_GET['cid'] );  try {   $stmt = $db->prepare($query);   $result = $stmt->execute($queryparams); } catch(PDOException $ex) {   die($ex->getMessage()); }   Also, here is how I connect to the database :  try {   $db = new PDO("sqlite:scores.db");   $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);   $db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);   $db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false); } catch(PDOException $ex) {   die($ex->getMessage()); }


Is the magnetic field zero inside an ideal conductor carrying a current?

By an ideal conductor, I mean one with zero resistance.   The question is not about a superconductor. As I know superconductor and conductor with zero resistance are not the same thing. The question is more about what happens to magnetic field inside a wire when its resistance approaches null.


I'll be short. When i use some Blender tools which should make a sub-menu appear in the left window, it doesn't always happen. For example, according to a tutorial I was following, I should have gotten the sub-menu you see in the picture after using "spin", but it doesn't appear. Maybe it's something related to the fact that I'm using Blender 2.75 while the tutorial uses some 2.5x? How can I get that sub-menu to appear?  Thank you in advance.


"Who are the neighbors of who?" : is this grammatically correct?

Temporary reopen note:  This question may appear at first blush to be about whether to use who or whom. However, the naturalness and grammaticality of this phrase has to do with the periphrastic genitive versus the saxon genitive, not whether to use nominative or accusative case. For this reason this is both a useful question and not a duplicate of the linked-to post here:        The Question:  Just to give a few details: I am writing an answer to an exercise, the exercise describes arranged objects, I want to state that the provide information allows one to deduce what are the neighboring objects.   How do I say it in one sentence - "who are the neighbors of who?" It does not sound correct to me...   I would appreciate if someone could point out if this is correct and would be grateful if there is a way to break this down or compare with similar language construction to help get familiar with this type of sentences.


How to init constant integer array class member? I think that in same case classic array isn't best choice, what should I use instead of it? class GameInstance{     enum Signs{         NUM_SIGNS = 3;     };     const int gameRulesTable[NUM_SIGNS][NUM_SIGNS]; //  how to init it? public:     explicit GameInstance():gameRulesTable(){}; };


Finding nilpotent and diagonalizable operators for a linear transformation $T$

Let $T$ be the linear operator on $\mathbb{R}^3$ which is represented by the matrix: $A=\begin{bmatrix}3 & 1 & -1\\ 2 & 2 & -1\\ 2 & 2 &0\end{bmatrix}$ in the standard ordered basis.  Show that there is a diagonalizable operator $D$ on $R^3$ and a nilpotent operator $N$ on $\mathbb{R}^3$ such that $T=D+N$ and $DN=ND$.  Find the matrices of $D$ and $N$ in the standard basis.  Here is what I've got so far. $\det(xI-A)=\det\left(\begin{bmatrix}x-3 & -1 & 1\\ -2 & x-2 & 1\\ -2 & -2 &x\end{bmatrix}\right)=(x-1)(x-2)^2$ But now I've got to find polynomials $h_1(T)+h_2(T)=I$ where $E_i=h_i$.  This was easy enough:  $E_1=(x-2)^2$ and $E_2=-(x-1)(x-3)$.  I've also computed the matricies $(T-2)^2$ and $(T-1)(T-3)$ beloe respectively: $\begin{bmatrix}1 & -1 & 0\\ 0 & 0 & 0\\2 & -2 & 0\end{bmatrix}$ $\begin{bmatrix}0 & 1 & 0\\ 0 & 1 & 0\\-2 & 2 & 1\end{bmatrix}$ This is where I'm stuck.  I'm not sure how to proceed from here in order to find $D$ and $N$.


How does a Windows 10 'digital license' activate the OS?

If you activated a free upgrade to Windows 10 or bought and activated   Windows 10 from the Microsoft Store, you have a digital license for   your device. This means you can reinstall the same edition of Windows   10 that your device has a digital license for without entering a   product key. During reinstallation, if you’re asked to enter a product   key, you can skip this step. Windows 10 will automatically activate   online after the installation is complete.   source:   Does MS digital license 'fingerprint' hardware information  during the free upgrade / activation and store it (at Microsoft) , so that the next re-install queries MS for the fingerprint and activates Windows 10?  Thought the disk drive may change, I expect that none of the other fingerprinted hardware will change.


I have a Audio time-series, to which I'm trying to detect the most significant parts of the signal, i.e. the voiced parts and forget the unvoiced parts.   $$ T = [0, 0, 1, 1, .....n] $$  I then compute the Spectral result of the time series, which, gives me a dimensional frequency representation of the input signal.   From this, I would like the determine the most significant elements of this, thus only leaving me with the voiced parts. I know this is possible using Principle component analysis and Independent component analysis, however, I'm trying to compute the following using SVD.  To try and understand the theory and application, I constructed a simple matrix:  $$ S = \begin{bmatrix}  1&0 \\   0&1 \\   1&1 \\   0&2 \\   1&1  \end{bmatrix} $$  In Python I have the following:  u, s, v = linalg.svd(S);   This therefore gives me three matrices, which, I understand that the following:  "s" -> this matrix is a diagonal matrix which is ordered from singular value to lowest   In order to re-construct the matrix, pick out the largest values of "s" and their corresponding columns in "u" and "v"  Thus meaning that the "s" corresponds to the magnitude which relates to the columns in "u" and "v".  But, I don't know how such can be re-constructed (using Python) and how it actually works..? My question mainly relates to taking a 2-dimensional vector and transforming this into another 2-Dimentsional vector containing only the most significant values.   Any help would be greatly appreciated


Fatal error: Class name must be a valid object or a string in .../common.inc on line 7924 on drupla site migration

I am migrating a site hosted on on Drupal 7.22, apache 2.2.22aa and php 5.6.9 from one linux server to another lunx server. I did a back up of mysql and apache htdocs folder and extract it on the destination server. But when I lunched the page on the server, I am getting the following error:      Fatal error: Class name must be a valid object or a string in .../common.inc on line 7924   I enabled the debug as below  /*  * Get the entity controller class for an entity type.  */ function entity_get_controller($entity_type) {   $controllers = &drupal_static(__FUNCTION__, array());   if (!isset($controllers[$entity_type])) {     $type_info = entity_get_info($entity_type);     $class = $type_info['controller class'];      // add debug.     if(gettype($class) == 'string' || gettype($class) == 'object') {       $controllers[$entity_type] = new $class($entity_type);     } else  {       print_r(debug_backtrace());     }     $controllers[$entity_type] = new $class($entity_type);   }   return $controllers[$entity_type]; }   Now I am getting the error as   Array ( [0] => Array ( [file] => ../includes/common.inc [line] => 7891 [function] => entity_get_controller [args] => Array ( [0] => node ) ) [1] => Array ( [file] => ../modules/node/node.module [line] => 952 [function] => entity_load [args] => Array ( [0] => node [1] => Array ( [0] => 15 ) [2] => Array ( ) [3] => ) ) [2] => Array ( [file] => ../modules/node/node.module [line] => 971 [function] => node_load_multiple [args] => Array ( [0] => Array ( [0] => 15 ) [1] => Array ( ) [2] => ) ) [3] => Array ( [file] => ../includes/menu.inc [line] => 593 [function] => node_load [args] => Array ( [0] => 15 ) ) [4] => Array ( [file] => ../includes/menu.inc [line] => 761 [function] => _menu_load_objects [args] => Array ( [0] => Array ( [path] => node/% [load_functions] => a:1:{i:1;s:9:"node_load";} [to_arg_functions] => [access_callback] => node_access [access_arguments] => a:2:{i:0;s:4:"view";i:1;i:1;} [page_callback] => node_page_view [page_arguments] => a:1:{i:0;i:1;} [delivery_callback] => [fit] => 2 [number_parts] => 2 [context] => 0 [tab_parent] => [tab_root] => node/% [title] => [title_callback] => node_page_title [title_arguments] => a:1:{i:0;i:1;} [theme_callback] => [theme_arguments] => a:0:{} [type] => 6 [description] => [position] => [weight] => 0 [include_file] => ) [1] => Array ( [0] => node [1] => 15 ) ) ) [5] => Array ( [file] => ../includes/menu.inc [line] => 472 [function] => _menu_translate [args] => Array ( [0] => Array ( [path] => node/% [load_functions] => a:1:{i:1;s:9:"node_load";} [to_arg_functions] => [access_callback] => node_access [access_arguments] => a:2:{i:0;s:4:"view";i:1;i:1;} [page_callback] => node_page_view [page_arguments] => a:1:{i:0;i:1;} [delivery_callback] => [fit] => 2 [number_parts] => 2 [context] => 0 [tab_parent] => [tab_root] => node/% [title] => [title_callback] => node_page_title [title_arguments] => a:1:{i:0;i:1;} [theme_callback] => [theme_arguments] => a:0:{} [type] => 6 [description] => [position] => [weight] => 0 [include_file] => ) [1] => Array ( [0] => node [1] => 15 ) ) ) [6] => Array ( [file] => ../includes/menu.inc [line] => 1755 [function] => menu_get_item [args] => Array ( ) ) [7] => Array ( [file] => ../includes/menu.inc [line] => 1770 [function] => menu_get_custom_theme [args] => Array ( [0] => 1 ) ) [8] => Array ( [file] => ../includes/common.inc [line] => 5292 [function] => menu_set_custom_theme [args] => Array ( ) ) [9] => Array ( [file] => ../includes/bootstrap.inc [line] => 2212 [function] => _drupal_bootstrap_full [args] => Array ( ) ) [10] => Array ( [file] => ../index.php [line] => 25 [function] => drupal_bootstrap [args] => Array ( [0] => 7 ) ) )


Alien Instrument produces "visual music", which a Human can temporarily experience

I would've read this short-story either in 2019 or 2020, possibly in a sci-fi compilation. The Gist of the Story goes as follows: The Protagonist, A Human (possibly a diplomat of some kind), arrives on a plant (potentially Mars) to meet with members of the resident civilisation (Martians). This Species, who I think were humanoid, share similar senses to Humans, all but for a smaller range of experience for either sight (colour-blindness) or smell. However they also have a sense that Humans do not, which is the ability to "perceive sound/waves", and so have created instruments which produce "visual music" which they view. The Diplomat overhears of this experience, and presses the Alien Diplomat that he has been meeting with to witness the phenomenon. The Alien Diplomat warns him that, although humans can experience this phenomenon through (some means that I can't recall; possibly through injection of a drug), these means, in the process, degenerate the very part of the brain which allows Humans to experience it. They then go on to say that those Humans who had previously experienced the phenomenon, later took to drugs or committed suicide, as the disparity between this experience and their day-to-day experiences were too great. The Protagonist aware of the potential consequences undergoes the procedure and experiences the phenomenon, after which, and in conclusion of the story, he notes his newfound state of depression.


Does the earth has any electric field as the earth's magnetic field is changing over time?

Earth's magnetic field changes over time because it is generated by a geodynamo   -Wikipedia   A time-varying magnetic field can produce electric field. So does the earth has electric field due to changing magnetic field?


How do I duplicate/array a line in a circle using GIMP?

I am trying to draw a speedometer with GIMP. Is there a easy way duplicate the line by rotating it about the center?


Split up the "not an answer" flag reason

I think it would make sense to split up the flag "This is not an answer" into three flag choices:   This should be a comment This should be an edit This should be a new question   If we had that, it would make it easier (and therefore more efficient) for mods to figure out what to do with answers flagged thusly.


Joint cdf and pdf of the max and min of independent exponential RVs

Let $X$ and $Y$ be independent random variables. Each has an exponential distribution with parameter $\lambda$.   Define two new random variables by  $W = \min({X,Y}) $  $Z = \max({X,Y})$  Find the joint cdf of $W$ and $Z$, and use it to find their joint pdf.  I know I need to start out by splitting up the event $\{W \le w, Z \le z\}$ as the union of $\{W \le w, Z \le z, X \le Y \}$ and $\{W \le w, Z \le z, X > Y \} $


What is the time-frame for The Force Awakens?

After watching Episode VII, I was talking to my wife: "Wow, that whole movie took place in an afternoon."  My wife looked incredulous and replied "What? Are you kidding? It took place over a couple of months."  Now it was my turn to sit there in disbelief. "Then why was Rey wearing her ratty desert rags the whole time, even on the ice planet?" I quipped.    My wife insisted that she wasn't, but I think that's probably because Rey was wearing Finn's jacket so it looked to my wife like a new outfit.   Anyway, I have no way to back up my argument and could very well even be wrong!  How much time passed in-universe during the seventh Star Wars movie?


Can a 12V battery give you a shock or not?

I am reading a book called "" and, on page 9, it says:  "Anyone who has dropped an adjustable wrench across the bare terminals of a car battery will tell you that short circuits can be dramatic at a "mere" 12 volts, if the battery is big enough"  They also show this image to exemplify the point above:    I have also watched , in which the guy touches both positive and negative parts of a 12V battery with his hand to see if he gets a shock, but, as you can see, nothing happens.  Having said that, I have 2 questions:  1) What does the size of the battery have to do with anything? The first statement says that short circuits can be "dramatic (...) if the battery is big enough". Why? For me the only difference between a small 12V battery and a big 12V battery is how long it can give you a shock for, but both would give you the same shock (ie, both would make the same current pass through your body).  2) Why didn't the guy in the video get a shock? He claimed that it is because the resistance of his hand is too high, which makes sense, but then why does the book quote (and its picture) make it look like you will for sure get a shock?


How to get more information about generalized binomial series

I am reading about generalized binomial series in Concrete Mathematics by Knuth,and FEW documents exist on the Internet(including wikipedia).What should I do to find more resources?If anyone could help,I would really appreciate it.


How do i prevent PHP-files form SQL-Injections?

I have a problem. I mad an software application and everything is running perfectly, however i found out that it is unsafe to use because i didnt prevent SQL-Injections. I googled a bit and found that you could you mysql_real_escape_string. However if i add this around a variable in my php file the whole php file will stop working properly. Does anybody know how to fix this?  Here is a example php-file that i am using:      <?php             $server = "";             $username = "";             $password = "";             $database = "";             $con = mysql_connect($server, $username, $password) or die ("Could not connect: " . mysql_error());             mysql_select_db($database, $con);             $id = $_GET['id'];             $sitze = $_GET['sitze'];             $farbe = $_GET['farbe'];             $kennzeichen = $_GET['kennzeichen'];             $automarke =$_GET['automarke'];             $rauchen = $_GET["rauchen"];             $essen = $_GET["essen"];             $trinken = $_GET["trinken"];                                 //Insert Fahrten             $sql = "INSERT INTO fahrzeuge (sitzplaetze, farbe, kennzeichen, automarke, rauchen, essen, trinken, user_user_id) VALUES ('$sitze','$farbe','$kennzeichen','$automarke','$rauchen','$essen','$trinken','$id')";             if (mysql_query($sql) === TRUE) {                 $records[] = "success";                 $idfahrt= mysql_insert_id();                 $records[] = $idfahrt;             } else {                 $records[] = "Es ist ein Fehler aufgetreten!!";             }                    //end Insert Fahrten              mysql_close($con);         echo $_GET['jsoncallback'] . '(' . json_encode($records) . ');'; ?>


How can I return the different prices of my quantities?

I have two tables, one containing all the quantities of products by country and another table that contains the prices by country.  When I add a condition for example country = "ch", I have the price correct for this country, I want to return different prices for all countries. How can I do that?  Here's my query:  SELECT      items.prod,     items.qty_fr,     items.date,     products.price FROM items LEFT JOIN products     ON products.product = items.prod WHERE     products.country = "CH" GROUP BY     items.prod   This is the result of my query:  It returns the first value      Here's my first table:     My second table :


Is it possible to publish an app based on a board game?

Usually the boxes says "all rights reserved" and "registered trademark". What does it mean? Could others make an app with the game's name and mechanic? Is it possible to sell it, put banner ads or make it free?


Comparing String to String is not working

I have this code and to me it seems like the logic is correct. When the value.toString() is entered it prints out 0123456789 just like it should because that is the value I entered in the editText field. Is there something simple that I am missing here or is this fine and I will have to look further afield.  Editable value = input.getText(); Log.i("Password entered: ", value.toString()); if(value.toString() == "0123456789"){     Log.i("Password entered: ", "yay it is working!"); } else {     Log.i("Password entered: ", "it is incorrect"); }


I recently downloaded Skype Beta which works fine but I have been getting an error while updating packages from Synaptic Manager:   W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list.d/skype-stable.list:1 and /etc/apt/sources.list.d/skypeforlinux.list:1 W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list.d/skype-stable.list:1 and /etc/apt/sources.list.d/skypeforlinux.list:1 W: Target Translations (main/i18n/Translation-en_US) is configured multiple times in /etc/apt/sources.list.d/skype-stable.list:1 and /etc/apt/sources.list.d/skypeforlinux.list:1 W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list.d/skype-stable.list:1 and /etc/apt/sources.list.d/skypeforlinux.list:1 W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list.d/skype-stable.list:1 and /etc/apt/sources.list.d/skypeforlinux.list:1 W: Target DEP-11 (main/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list.d/skype-stable.list:1 and /etc/apt/sources.list.d/skypeforlinux.list:1 W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list.d/skype-stable.list:1 and /etc/apt/sources.list.d/skypeforlinux.list:1   NOTE: It hasn't been long since I switched to Linux so if someone can explain the error and provide some help, I'll appreciate it.


How can 16th-level characters mitigate damage from a lethal (long) fall?

The core question  What is a way for a 16th level character to avoid potentially fatal falling damage - but are not Feather Fall, Levitate, magic items that grant the properties of these spells, or the Monk's and Barbarian's class features (Slow Fall and Rage)?   The context  I am planning a short campaign in D&D 5e that starts out with my players imprisoned upon an airship. The airship gets attacked, and all passengers are hurled towards the ground from a substantial height (more than 3000 feet).   The details   These are 16th-level characters (because we want to do a high-level adventure). I won't tell my players that they "should" or "might take" magical starting equipment or spells that give them flying speed, etc. They are stripped of their equipment (because they were imprisoned, by even stronger characters). The fall should be lethal, if they do not intervene. I'm considering moving the damage cap for falling up for this very reason (I plan to use the "a creature falls 500 ft at the start of a round" rule). I want to avoid the "raging barbarian just fell out of the sky and just tanks the impact" scenario, if possible. I've modified the fall damage as follows: terminal velocity is about 150 ft/s IRL, about 80 in 5e under the "500ft per round or 6 seconds" rule, so I was thinking maybe 40d6 (a quarter of the max velocity in feet). Enough to potentially kill/make high-level players unconscious.   My current ideas are as follows:   The cargo from the ship - that contains their equipment, which they can recover later in the campaign - also includes Scrolls of Feather Fall. The scrolls are scattered in the air around them and can be grabbed and used. This has the caveat that Feather Fall is only on the Bard's, Sorcerer's, and Wizard's spell list, so if we don't have one player with this class, RAW they cannot read this scroll. A player could grab a sail from the airship and use it as a improvised parachute - this is probably far out of the rules, but I might rule this as a DC 20 Acrobatics or Athletics check? The players can attempt to fall into water, a lake or something similar. This will reduce their damage, but might still kill them.     I am looking for a solution that   works for (almost) all classes or   lets one player save the whole party or    somehow negates the fall damage otherwise


I'm thinking about making something like this in (Xe)LaTeX:    Would it be feasible to make?


If I have opened an output stream like this:     ofstream to(output_file);  How may I print new line (Looking to support different os)?  to << "\n";  to << "" <<endl;


Can one PC be used by two users at the same time via dual-monitor?

Since modern PCs can use two screens at the same time I wonder if it is possible to plug in two keyboards and mouses as well to have the two screens run two (more or less) independent X-sessions at once?


Prove that ${{n+m-1}\choose{m}}$ is the number of ways to select m items from a set of n items with repetitions allowed.

How do I prove this statement?  As per my understanding, the number of ways to select $m$ items from a set of $n$ items, with repetition, is simply $n^m$, as each round of selection still deals with $n$ items.


Timeout function if it takes too long to finish

I have a shell script that loops through a text file containing URL:s that I want to visit and take screenshots of.  All this is done and simple. The script initializes a class that when run creates a screenshot of each site in the list. Some sites take a very, very long time to load, and some might not be loaded at all. So I want to wrap the screengrabber-function in a timeout script, making the function return False if it couldn't finish within 10 seconds.  I'm content with the simplest solution possible, maybe setting a asynchronous timer that will return False after 10 seconds no matter what actually happens inside the function?


How to update display command result in one line?

I want to clear and update display text in loop without new line. I try the following code:  echo -ne "some text\r"  But it is not really update the line but just overwrite the line without clear the previous one. In the result, display are overlapped and display become messy.


Differentiable function has measurable derivative?

Let $f:[0,T] \to \mathbb{R}$ be a differentiable function. Is it true that $f'$ is measurable?   If so, is this also true if $f$ is differentiable almost everywhere?   Sorry for lack of effort but I don't have any clue about the answer.


Paradox of weight increasing with relative velocity

I am traveling past earth near the speed of light, I see an 80kg (rest mass) man standing on a scale and it reads 80 kg. However, due to special relativity I see the mass of the earth and the man are both doubled and hence the gravitational force between them should be 4 times and the scale should read 320kg. The reading on the scale display can't be both 80kg and 320kg.  What is the explanation?  I did search both the web and stack exchange and could not find an answer. I saw the "duplicate post" before posting and it refers to a moving mass on a stationary surface whereas this case is 2 masses that are stationary relative to each other and a observer moving relative to both, I see this as a different case and look forward to any solutions.


When highlighting text in a PDF exported from InDesign, the highlight doesn't select the text in the right order. How can I fix this?


Every power series is the Taylor series of some $C^{\infty}$ function

Do you have some reference to a proof of the so-called Borel theorem, i.e. every power series is the Taylor series of some $C^{\infty}$ function?


How to prove periodicity of $\sin(x)$ or $\cos(x)$ starting from the Taylor series expansion?

With the Taylor series representation of $\sin$ or $\cos$ as a starting point (and assuming no other knowledge about those functions), how can one:  a. prove they are periodic?  b. find the value of the period?


How does a load balancer get around the 64k port limit?

When a request comes in, it gets rerouted to one of several available servers for the request. But there's only 64k ports available so at any given time there can only be 64k outgoing requests max. So how can some websites serve millions of concurrent requests then? If someone could clear up this confusion that would be awesome. Thanks!


python check for ip address for connected router

I am building a python program to check for security of a home network and for that I need a way to check if a computer has internet connection and if yes I want the IP address of the machine to which it has connected to the network. So for example my computer is connected to my home router and my local IP address(address of my computer on the router) is 192.168.22.128 i want my program to print that ip address for me.


ssh executes remote command in the background

I know I can execute a command on a remote machine using "ssh ip_addr "command"", and this will return after 'command' exits. How can I execute a command in the background on the remote machine so that I don't need to wait for the 'command' to exits? I tried ssh ipaddr "command &" but it didn't seems to work. An alternative is ssh ipaddr "command" & which put the ssh command in the background but it doesn't look clean. Suggestions?


How to show 'Table' instead of 'image' when I have a table in the form of image?

I don't know if the question has been asked or not.   I have a table in the form of image and I want to put instead of "Figure 1", I want to put instead "Table 1",   so on my way to show this, I turned to use the following form,  \newtheorem{table} {Table}   then use it for example,   \begin{figure} \begin{table} \includegraphics {image1.png} \end{table} \end{figure}   but this makes the table far away from the image, I just want it at the same place as image, so I hope find here a solution for this problem.


Hi all I am working on a citation for my whitepaper I used  to generate my .bib file. However I can't get the citation to show   Here is the code in my LaTeX file    \documentclass{article}   \usepackage{biblatex}   \addbibresource{References.bib}   \begin{document}  Someone must have found a simple solution  \cite{references}.  \printbibliography   \end{document}   Here is my References.bib file    @misc{references,    month = {09},    title = {bibliographies - How do I add "citations" at the end of the document as done here?},    url = {https://tex.stackexchange.com/questions/134180/how-do-i-add-citations-at-the-end-of-the-document-as-done-here},    urldate = {2020-05-01},    year = {2016},    organization = {TeX - LaTeX Stack Exchange}  }   Here is the output of the code    I am using ubuntu, texmaker and all files are in the same directory   Running F11 bibtex in TexMaker I get the following error  Process started   This is BibTeX, Version 0.99d (TeX Live 2017/Debian) The top-level auxiliary file: Using References-bib.aux I found no \citation commands---while reading file Using References-bib.aux I found no \bibdata command---while reading file Using References-bib.aux I found no \bibstyle command---while reading file Using References-bib.aux (There were 3 error messages)   Process exited with error(s)   I'm not sure if I am missing anything else THANKS ALL!!!


Figure refs stop working after I added a new counter

I was using the amspset document class for generating exam practice problems. I had wanted to add some referencing to the problems so I started a new counter like this (adapted from some Tex Exchange post)  \newcounter{P} \newcommand{\plb}[1]{\refstepcounter{P}\label{#1} \textbf{P-\ref{#1}.}}  \begin{problem} \plb{p1} A parallel-wire transmission line is constructed of \#6 AWG copper wire (diameter $d=0.162$ in., conductivity $\sigma_c=5.8\times 10^7$ S/m) with a 12-inch separation in air. Assuming no leakage between the two wires, find $R'$, $L'$, $G'$, and $C'$. Assume a working frequency of 1 MHz. \end{problem}  \begin{solution} Using Table.~\ref{tab:tlparam} and Fig.~\ref{fig:tlempl},  \[ Rs = \sqrt{\pi f \mu_c/\sigma_c} = 2.61\times10^{-4}~ \Omega\] \[ R' = \frac{2R_s}{\pi d} = 4.04\times10^{-2} ~\Omega\text{/m} \] \[ L' = \frac{\mu_0}{\pi} \ln{\frac{2D}{d}}=2.0~\mu \text{H/m} \] \[ C' = \frac{\pi \epsilon}{\displaystyle\ln{\frac{2D}{d}}}=5.56 ~\text{pF/m} \] $G'=0$ because the problem states that there is no leakage between the two wires. \end{solution}  \begin{figure}[ht] \begin{centering}     \includegraphics{fig24}     \caption{(Fig.2-4 from FAE) A few examples of transmission lines.} \end{centering} \label{fig:tlempl} \end{figure}  \begin{table}[ht] \caption{(Table 2-1 from FAE)Transmission-line parameters $R'$, $L'$, $G'$, and $C'$ for three types of lines.}     \begin{tabular}{c}         \hspace{3cm}\includegraphics{tb21}     \end{tabular} \label{tab:tlparam} \end{table} ... and more   Now all the figure references stop working, I get "Fig. " instead of "Fig. 1". The table references are alright though. Any idea what the problem could be?


Using newcommand to produce (simple) newcommands

I would like to have, say, two custom comment macro for every author. For example suppose there are two authors Alice and Bob and they would like to have commands:  \newcommand{\acom}[1]{\textcolor{green}{#1}} \newcommand{\aissue}[1]{\textcolor{red}{\textbf{#1}}}   for Alice a maybe with different color scheme for Bob. Of course, Alice can write these but it is a bit annoying.  Now, suppose Cecil joins our team. Ideally, I would like to have a command  \registerAuthor{Cecil}{yellow}{purple}   since then it is easy to ask Cecil to add his command and everything goes smoothly (otherwise Alice has to do this every time; and imagine if we have 20 different macros). Is there any possible workaround?


How can I produce exact rounded values in C++?

I've been looking into rounding doubles by a specified decimal place in C++. I've found a way to accomplish exactly that, but it seems to be slightly off. There is a small imprecision tacked on to the end of the rounded value.  Here's a sample program I made to show the problem... In this example, the value 0.929383191 should be rounded to 0.929 (or at least 0.92900000000000000). However, I am getting a value of 0.92900000000000005. Which is a fairly insignificant difference, but I'd like it to be precise. Is that possible?  #include "stdafx.h" #include <math.h>  // round float to n decimals precision const double RoundToNearestDecimalPlace(    double value,     int decimal_place) {    if (value == 0.0)       return 0.0;     double factor = pow(10.0, decimal_place - ceil(log10(fabs(value))));    return round(value * factor) / factor; }  int main() {    const double Result = RoundToNearestDecimalPlace(0.929383191, 3);     return 0; }


How do you put a circle on top of an exponential symbol


When should a trusted user use their delete votes on an answer?

I recently hit 20k rep and gain the privilege to delete answers with negative score.  When should I use my delete votes on answers, given that non-answers can be flagged and resolved with single binding vote by community moderators?


Is it common to ask questions in English by means of intonation alone? For instance the following line from a webpage confuses me:   Since Hindi does not have the auxiliary do, learners are prone to asking questions by means of intonation alone: She has a brother?    The obvious way to ask this question is "Does she have a brother?". But to me sentences like "You live here?" or "You went shopping?" sound very natural.


Transit visa for Nepali citizen in Guangzhou

I am Nepali passport holder traveling to Nepal with China Southern Airlines from New York. I have 6 hours transit (both back and to Nepal) in Guangzhou, China. I am not getting out of the airport. I wonder if I am eligible for 24-hour visa free transit. I am posting this because I saw nothing on this specific airport or China Southern Airlines online. Is Nepali passport has some rules on it?


I have two files file1.txt, file2.txt. I want to select records which are common to both file1.txt and file2.txtbased on column 2 and column 3 and copy them to out.txt with additional column(column 4 from file2.txt).   Sample Input:  file1.txt  abc 1 a f11 f13 f14  abd 2 b f12 f14 f13   abe 4 d f13 f16 f12  acf 5 s f14 f15 f19   file2.txt  abc 1 a f21 f23 f24  abd 1 b f21 f24 f23   abe 4 d f24 f26 f22  acf 6 s f23 f25 f29   Desired output  out.txt   abc 1 a f11 f13 f14 f21  abe 4 d f13 f16 f12 f24   I have asked a similar  earlier on how to work with three files and extract similar output based on similar input for better understanding. I'm new to Unix world and been learning on how to do file processing. Based on that I have tried the below piece of code using awk but didn't work. Could someone please check and suggest, what went wrong ?  awk 'FILENAME == ARGV[1] {     m[$2,$3] = 0; z[$2,$3] = $6;     next; } {     if (($2,$3) in m && m[$2,$3] == 1) {         print $0 " " z[$2,$3] >"out.txt";     } }' file2.txt file1.txt


Quotient of complex polynomials ( alhfors complex analysis)

The Problem    My Work  We know that:  $\frac{Q'(z)}{Q(z)}=\sum\limits_{k=1}^{n}\frac{1}{(z-\alpha_k)}$  Thus  $\frac{P(z)}{Q(z)}=\sum\limits_{k=1}^{n}\frac{P(z)}{Q'(z)(z-\alpha_k)}$  This is about as far as I have traveled any ideas?  Possible Ideas  I get the feeling that I should use :     But I am not sure of it's relevancy.


how do i access the Ubuntu one folder while using Ubuntu 14?  I am doing a school project and need to solve this.    I have tried searching for it, and can't find it anywhere in the Operating System.  I have also tried updating my software to current, but still no luck.


Tabular With Code - "" Are Not Recognized

This table  \begin{tabular}{ | l | l | } \hline Ausdruck & Wert \\ \hline int x = 49; & -- \\ \hline !(x >= 0 \&\& x < 50 || x > 50 \&\& x <= 100) & true \\ \hline x++ == 49 || x-- == 49 & false \\ \hline !(x >= 0 \&\& x < 50 || x > 50 \&\& x <= 100) & true \\ \hline int k; scanf("\%d", \&k); & -- \\ \hline !(k > 0 \&\& k\%10 <= 7) == (!(k > 0) || !(k\%10 <= 7)) & true \\ \hline \end{tabular}   produces the following result:    Issues   > is output as ¿ < is output as ¡ || is output as ——   It should look like    Any suggestions on how to put those code snippets inside the table?


how to get numbers under numbers in LaTeX

So, I have an equation and I need that the matrix  near equation be written like that in LaTeX      0 2 0  A= 0 0 5       0 0 4    But I get that:  0 2 0  some equation A= 0 0 5  0 0 4                                            0 2 0 How get this result?: `some equation` A= 0 0 5                                          0 0 4


How to addClass click and removeClass when click again outside or click other element?

This is my code. I want to when dblclick in element <li> active event and removeClass when click outside or click into other element.    initTodoITem: function (todo, lbContent, inputEdit) {    var item = document.createElement('li');     item.setAttribute('class', 'todoItem');      item.addEventListener('dblclick', function (){       lbContent.classList.add('edit');       inputEdit.classList.remove('edit');       inputEdit.classList.add('editing');     });      return item;   },


Split returned string into muliple columns

I have a string containing a hierarchy of items separated by a '/' character.   E.g.  Class\Order\Family\Genus\Species  I need to split out this string such that each value is its own column as well as displaying the original full string  E.g.  Mammalia\Carnivora\Felidae\Panthera\Panthera tigris   Mammalia\Carnivora\Felidae\Panthera\Panthera leo   Mammalia\Carnivora\Felidae\Panthera\Panthera pardus     becomes  Classification Class Order Family  Genus Species   -------------- ----- ----- ------  ----- ------- Mammalia\Carnivora\Felidae\Panthera\tigris Mammalia  Carnivora Felidae Pathera tigris   Mammalia\Carnivora\Felidae\Panthera\leo Mammalia  Carnivora Felidae Pathera leo   Mammalia\Carnivora\Felidae\Panthera\pardus  Mammalia  Carnivora Felidae Pathera pardus     Finally, not all string will have 5 values so the script will need to enter NULL for values that don't exist  E.g.  Mammalia\Carnivora\Felidae     becomes  Classification Class Order Family  Genus Species   Mammalia\Carnivora\Felidae Mammalia  Carnivora Felidae NULL NULL


How to get a real time notification of Questions posted in SO for a particular tag

Is it possible to get real time notification of new questions being posted on SO for a particular tag.  I have tried Google Reader but it is not realtime. Are there any real time Feed readers for SO


From a philosophical standpoint, $0!=1$ as it is possible to arrange nothing in one way--there isn't.  Are there any rigorous proofs showing this concept?


Can I search for 2 different tags at the same time?

I am aware that you can search for multiple tags such as [css] and [jquery], which will show questions with both of those tags. But is there a way to search with 'or' rather than 'and'? So that the search will show any question that has any tag that's listed?


Determinant of the following n×n matrix:

Determinant of the following $n \times n$ matrix: $$\begin{pmatrix} 2\cos \theta& 1 & 0 & \ldots & \ldots & 0 \\ 1 & 2\cos \theta & 1 & \ddots & & \vdots \\ 0 & 1& 2\cos \theta & \ddots & \ddots & \vdots \\ \vdots & \ddots & \ddots & \ddots & \ddots & 0  \\ \vdots &  & \ddots & \ddots & 2\cos \theta & 1 \\ 0 & \ldots & \ldots & 0 & 1 & 2\cos \theta\\ \end{pmatrix}.$$  Letting given matrix determinant as $D_n$, I find a relation $D_n-2\cos \theta D_{n-1}+D_{n-2}=0$, but after that how  I calculate $D_n?$ Please help.


How to understand the definition of vector and tensor?

Physics texts like to define vector as something that transform like a vector and tensor as something that transform like a tensor, which is different from the definition in math books. I am having difficulty understanding this kind of definition. To me, it goes like this:   First we have a collection of bases or coordinate systems (do these represent reference frames?) and the transformations between them. A vector/tensor is an assignment of an array of numbers to each basis, and these arrays are related to each other by coordinate transformations.   I am wondering how coordinate systems and transformations are specified.    Do we need all possible coordinate systems and transformations to define a vector space or just a few of them? How to define the concept of basis and coordinate transformation without completing the very notion of vector?


Who's pushing old questions to the front?

Consider  - it's from mid January, it has one answer + some comments. The last obvious action is from Jan 19. Who's pushing that question to the front page?


So I upgrade to Ubuntu 17.04 from 16.10 with excitement.  Before when I upgraded to 16.10 , any program (like wine) or any file was deleted and wine was working pretty fine.   But when I upgraded to 17.04, all files and programs were deleted. So I said "Ok,no problem." and tried to install wine.   But there was no wine in Software Center. So I installed wine from terminal but there's no "c disk" when I write c to "search"(I can only access it via .wine).   So who has the problem? Me or Ubuntu?


Swap Used when there is unused Physical Memory

I'm running on OSX Yosemite and notice that although there is 7 GB of memory unused, there is still 130 MB of memory used for swap.  Are any apps actually using swap space, which I assume resides on my harddisk? Is this a situation to be concerned with, or is this normal?  I can't figure this out despite reading up on the memory statistics in Mac.


Reputation items in the achievements dropdown don't add up

In the top bar, the green “achievements” number shows +14. But when I open the dropdown, I see four items totalling +20. Why does the total not match the sum of the items?    No lower entries were highlighted.


Who is Monica Cellio?   I’m new here and not familiar with why there are so many questions regarding her.  I can’t find her on SE either.


How can I remove the option to eject SATA drives from the Windows 7 tray icon?

The Safely Remove Hardware icon in Windows 7 offers the ability to eject my SATA drives, including the boot drive. I don't see myself ever needing this - especially not from the convenience of the tray icon.  Is there a common BIOS setting to disable hot-swappability?


Several Questions on Smooth Urysohn's Lemma

The smooth version of Urysohn's Lemma is      Let $A,B$ be two disjoint closed subsets in $\mathbb{R}^n$ with one of them compact, then there exists a smooth function $f: \mathbb{R}^n\to [0,1]$ such that    $$f(A)=0\qquad f(B)=1$$   For a proof, for example , see .   I'am stuck on the following problems in the smooth version    How about the counterexamples without the condition that "one of them is compact"?  Can we make more strict conclusion that $f^{-1}(0)=A$ and $f^{-1}(1)=B$? Note that it implies $f(A)=0$ and $f(B)=1$.    Without the requirement of smoothness, we can release the condition of compactness and make more strong requirement of inverse image, since we can simply take $f(x)=\frac{d(x,A)}{d(x,A)+d(x,B)}$. Clearly, it is not smooth in general.   The idea of the above link does not holds even for the following regular figure.


Swapping desktops (unintentionally) on Mavericks

I am using OSX Mavericks 10.9.2 and I have 4 desktops that I use in my daily workflow. From time to time Desktop 2 and Desktop 3 switch places and I cannot figure why. Probably when moving from desktop to desktop (sometimes I use 3 finger swap and sometimes Control^#) I activate some shortcut.   Does anybody what is shortcut for swapping desktops or some other explanation for this? And how to disable it :)  Thanks


How should I solve this equation system without using logarythms,using just a simple method? (E.g. turning it into a quadratic one using t)  $$\left(\frac{3}{2}\right)^{x-y} - \left(\frac{2}{3}\right)^{x-y}=\left(\frac{65}{36}\right)\\ xy-x+y=118$$


Is it possible to have single theorems without numbering? I would like to be able to switch them off individually with asterisk-* or have a nono-theorem environment.  \newtheorem{theorem}{Theorem} \newtheorem{nono-theorem}{Theorem}[]


Is there a formula for the Tribonacci sequence, where  the formula for Fibonacci is:  $$F_n=\frac{(1+\sqrt 5)^n-(1-\sqrt 5)^n)}{2^n\sqrt 5}.$$


make and the mkdir command behaving differently on MacOX vs Ubuntu 20.04

I have discovered something odd with the mkdir command when it is being used in a Makefile and it behaving differently between OSX and Ubuntu 20.04. Just wondering if this is expected behaviour, or have I discovered a bug? The suspect command is: mkdir -p -m 0755 ./output/themes/simple/{css,javascript,webfonts,image} This command works perfectly at the bash/zsh command line, creating the directories: output/themes/simple/css output/themes/simple/javascript etc. On a OSX machine using the zsh shell. When running the above command in a Makefile it works as expected creating the separate subdirectories. However, using the same Makefile on a Ubuntu 20.04 desktop (the file is on a server and both machines can see it) the command is creating the following: output/themes/simple/{css,javascript,webfonts,images} It is as if the command is seeing the last component of the directory path as a string and not enumerating it as it does on the command line. Make on Linux is:  GNU Make 4.2.1 Built for x86_64-pc-linux-gnu Copyright (C) 1988-2016 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later  This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.  Make on OSX is:  GNU Make 3.81 Copyright (C) 2006  Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. This program built for i386-apple-darwin11.3.0  I do not think it is difference between shells, mkdir is not a builtin on the bash Ubuntu provides. Work around is to separate the mkdirs into separate commands, but I was quite surprised that the make/mkdir did not work correctly on the Linux box. Any thoughts? Cheers Jim


How to delete a file named -something with rm

When I have a file named -19-5-20674., how can I delete that file? When I use sudo rm: $ sudo rm -19-5-20674. rm: invalid option -- '1' Try 'rm --help' for more information.  What can I do?


Bug in flutter calculation,This is very interesting result : print('result ${43.12 - 93.12 + 50}');   output -> result -7.105427357601002e-15   print('result ${43.12  + 50 - 93.12}');   output -> result 0


Buzzing bees in my manor in Skyrim are driving me nuts - how do I get rid of them ... permanently?

I assume there is no possible way to edit a completed manor wing built in Skyrim, and I made the mistake of adding a greenhouse wing. Now I have bees overrunning that half of the manor, and the buzzing is loud, obnoxious, and driving me nuts! Is there a possible way to eliminate them permanently? I would simply remove that wing and add a bedroom or enchanting tower, but I reckon ya only get one go 'round when you add a wing, which is really kinda idiotic this option is not made available. So I am stuck with buzzing bees unless there is a fix? Game system I use is PS3.


How can I find the last digit of $17^{68}$ and the last both digits of $14^{200}$?

I have to compute the last digit of $17^{68}$ and the last both digits of $14^{200}$.  For the first exercise, I get  $$17^4=...1 \Rightarrow  17^{68}=(17^4)^{17} = (...1)^{17}=\ .... 1.$$  For the last exercise, I don't know how I can do it.


Should "Deletion successful" confirmation be red, or green?

What color should a deletion confirmation message be?  This is related to the question , but different because this question asks about a passive confirmation message and not the active delete button.  One might say green, the typical success color, but the delete button was red and it looks weird. Making the message red, because you just deleted something, also makes no sense because red is supposed to be for errors.  In my specific case it's about rejecting or accepting proposals. The options are:   (success)   (danger)   (warning)   (info)  Making rejected bold puts more emphasis on the difference between rejected and accepted. The text could also be changed to "You have successfully rejected the proposal," which also puts more emphasis on the actual action regardless of the color.  Using no color, a grey background with black text, looks weird. It doesn't look like a notification anymore at all, so I don't really consider it an option.  Finally someone suggested having no message at all, since the proposal will be deleted from the list of proposals. That deletion in itself should be enough feedback, according to that person. I personally disagree, though. It feels weird.  Overall, I lean towards green or blue (success or info). Red messages should be a failure of some kind, and the yellow warning also makes me feel like there is additional action I should take. Green doesn't look like a rejection (the reject button is red, the approve button is green) and blue also feels off for some reason.  Which option should be used?


Find elements of a group $\operatorname{Aut}(\mathbb{Z_{20}})$ automorphisms of cyclic group $\mathbb{Z_{20}}$. Is $\operatorname{Aut}(\mathbb Z_{20})$ cyclic group?   $\mathbb{Z_{20}} = \left\{0,1,...,19\right\}$  We know that an automorphism is an isomorphism from group G into the same group.  Let $\phi$ be random element of $\operatorname{Aut}(\mathbb{Z_{20}})$. Group $\mathbb{Z_{20}}$ is generated by $1$ and $\phi$ is a group homomorphism so $\phi$ is uniquely designated via image on element $1$.  Automorphism $\phi$ doesn't change group order so $\phi(1)$ must be of order $20$. So $|\operatorname{Aut}(\mathbb{Z_{20}})| = 20$.  These are my only observations but I don't know what to do next to get to specific elements


Opening links using javascript, from within an iframe

I made a custom google map using the api and in it are custom controls that link to pages. I made the map for a wordpress site but as it's a hassle for me to get the various javascript elements working natively, I created the map as a html file and uploaded it to the server and used an iframe to display it. The link buttons work fine when the map html is opened directly but when it's loaded into an iframe in the wordpress page, the buttons no longer work.  ButtonUI.addEventListener('click', function() { window.parent.location.href= "LINK";   this is the snippet for the button, is there another way to implement the link that would work when the code is loaded by an iframe?


Using showInputDialog to get user input to quit program

I am trying to use showInputDialog to get the user to enter N or n when they want to quit the program. I'm using a do-while loop and I think my logic is wrong. When I enter N or n the program just continues to run through the loop.   Below is my code:  public static void main(String args[]) {     MyClass app = new MyClass();     String quit;     // get user input until they quit     do {          boolean validEntry1 = false;         do {             String userEntry;             double num1;             // check for valid numerical entry and catch invalid entries             try {                 userEntry = JOptionPane                         .showInputDialog("Enter number 1");                 num1 = Double.parseDouble(userEntry);                 app.setNumberOne(num1);                 validEntry1 = true;              } catch (NumberFormatException e) {                 JOptionPane.showMessageDialog(null,                         "Please enter a valid number");             }         } while (!validEntry1);          // gets user input for number 2         boolean validEntry2 = false;         do {             String userEntry1;             double num2;             // check for valid numerical input for num2             try {                 userEntry1 = JOptionPane                         .showInputDialog("Enter number 2");                 num2 = Double.parseDouble(userEntry1);                 app.setNumberTwo(num2);                 validEntry2 = true;             } catch (NumberFormatException e) {                 JOptionPane.showMessageDialog(null,                         "Please enter a valid number");             }         } while (!validEntry2);           //this method gives the result of a multiplying num1 and num2          app.output();          // prompt user to continue         quit = JOptionPane                 .showInputDialog("Enter N or n to quit. Enter any other key to continue.");      } while (quit != "N" || quit != "n"); //this is where I am having issues, It continues to loop regardless of what I enter. }// end of main   Any suggestions on where I am going wrong?  Is there a better way to get user input to quit in the gui?


Is it possible to extend your stay after entering the US under VWP?

I am currently holidaying in USA and have entered the states on a ESTA visa waiver, I booked my return ticket two weeks after the 90 day ESTA expires (my fault) naively thinking it wasn't a big deal, I went on a short visit (3 days music festival) to Quebec from Maine, upon re-entering the states the border protection official made it quite clear that I would have to return to Australia when the 90 days are up.  Now I am only on holidays and have no medical emergency, but I am having a great time sailing here, is there anything I can do to extend my stay (14 days) to the date of my pre purchased plane departure ?


Nullpointer Exception on null check statement

How is the null check statement below throwing a Nullpointer Exception? Is the request perhaps null? I'm confused Somebody help.  if(!getTGTid(request).equalsIgnoreCase(null) ||  !getTGTid(request).equalsIgnoreCase("")) {   Method  private String getTGTid(HttpServletRequest request) { return request.getParameter("tgtId");  }


Can anyone help me? I am currently a Windows 10 user on my laptop and I want to dual boot my laptop so I can have Ubuntu and Windows 10. Can anyone give me an instruction on how to do it?


Wanted: question mark instead of bibtex key for missing citations (biblatex)

Instead of having the citation key showing up in the document for missing references, I want to only have [?], as it is the case when using the default bibtex without biblatex. This behavior is driving me crazy, as it messes up all the formatting (especially in tables). I want to focus on writing and only later on deal with the erroneous citations.  This question is related to    and its MWE can be used. However, as pointed out beforehand, I want the question mark in the text instead of the citation key to not mess up the formatting (for missing citations).


I'm executing grep command in my C code with the function execl(), and I want to use the output of this command in my C program. How do I do it?


n x n matrix has the same eigenvalues as its transpose

I am trying to prove that a $n \times n$ matrix $A$ and $A^T$ have the same eigenvalues.  I can prove that $A$ and $A^T$ have the same entries on the diagonal, but I am not sure where to go from there.


How do portraits work in the Potter-verse?

It's accepted fact that pictures move, and that portraits talk.  However, why is it that the subject of a portrait can be in only one frame at a time?  Also, what happens, if a new portrait is made? As soon as it is complete, does the subject disappear (to maintain that there is only one subject across all the frames)?  On an extra(and possibly useless) note, I remember that Harry once got a Chocolate Frog card of Dumbledore, and Dumbledore shortly walked out of it. Ron commented something along the lines of, "Can't expect him to hang around all the time." So, do Chocolate Frogs also share their subjects with portaits? I understand that photographs, atleast, seem exempt from this logic. No idea about celebrity posters(like those of the Cannons and Krum) either.  Lastly, what is the point of having multiple portraits if they are almost always empty? Doesn't it defeat the point of having a magical portrait? I would find it offensive if I went to the trouble of having a portrait put up, only for the subject to promptly walk out.  The following questions touch upon a similar topic, but focus on the magic behind the sentience of the subjects, rather than their availability:


testfor a cocoa bean in a player inventory

I have been trying to figure this one for about an hour now, yet I still can find out how to detect cocoa beans in a player inventory in 1.11.2. The command I used was:  /testfor awesomeianman {Inventory:[{id:"minecraft:dye",Damage:3}]}   Whenever I tried this, it didn't have an output! Could someone please help me, and tell me if the command is completely wrong?


How can we prove simply that acceleration for every freely falling body is equal to $g$?

If I allow two bodies of different masses to fall freely from same height towards the earth, how can I prove that the acceleration produced in both was constant and equal to gravity.


Dynamically adding a CSS class to a view row with template.php

I've actually reached the bottom of Google trying to figure out how to add a css class to each row of a view.  The trick is that I need the class for each row to be dynamically determined based on some of the data from the node that the view pulls from.  The function that pulls this off neatly for the node is -   function pgc_preprocess(&$variables) {   $node = $variables['node'];   if ($node->type == "event") {     $variables['event_class'] = '';     $num_trainers = $node->field_number_of_trainers[0]['value'];     $count = count($node->field_trainer);     if($count < $num_trainers) {         $variables['event_class'] = 'red';     } else {         $variables['event_class'] = 'green';     }     return $variables;   } }   The point of this is to color code an event that hasn't had enough folks sign up.  There will be a list of events on the front page, and I need  them to be color coded also.  I really hope there some simple solution along the lines of -  function pgc_preprocess_views_view_unformatted(&$variables) {   // Magic here, preferably having something to    // do with the function I already wrote. }   Just dropping <?php print $event_class ?> in the view .tpl doesn't do it.