Why won't my JOptionPane show up if there's no text in my JTextField?

I'm working on a login screen for my game, and everything works fine, except for one thing. When I check to see if the text from the JTextField == "", it still launches the game and whatnot.   Here's a look at my code:  public void attemptLogin(String username, String passcode) {     if (username != "" && passcode != "") {         System.out.println(username);         System.out.println(passcode);     } else if (username == " " || passcode == " ") {         JOptionPane.showMessageDialog(null, "Put in your credentials!", "Hey you!", JOptionPane.ERROR_MESSAGE);     } }   }  In my main class, it goes:  public void actionPerformed(ActionEvent action) {         if (action.getSource() == login) {             gamelogin.attemptLogin(username.getText(), passcode.getText());         } else if (action.getSource() == register) {             account.registerAccount();         }     }   Now what must happen is that if the JTextField comes up blank, then show a JOptionPane and if not, login to the game (added later), but evidently, this is not happening. It just outputs white space in the console.  Thanks in advance! :)


Is it possible to exclude questions I've already answered from the search criteria?

Recently I asked if it were possible to find questions with just one answer and as a result we got an .  That's great, but ...     Is there a way to restrict the search to questions where that one answer isn't mine? That would help. :-)   It's certainly possible to search for , but it's not possible to exclude your own posts as far as I can tell:   -user:me searches for posts that . user:1-67 doesn't search for posts from user #1 to user #67, but searches for .  (And I'm not sure that will help anyway since I don't think it would be possible to simultaneously exclude 69-max(userID).) -Ericson searches for posts that , but since my last name is in the the metadata and not the searchable portion of posts: no joy.   And of course none of this will actually work to eliminate the questions that that I've answered already and want to ignore.  In general, If I'm involved in a Q&A (or ) the notification procedures do a good job of keeping me up-to-date with developments.  But when I search, it's often to find questions I've not noticed before.  So being able to eliminate questions I have already answered would be a generally useful feature for me.


Please save my edit summary when edited within grace period

Steps to reproduce:   Edit the body of any post. Edit it again immediately, but only modify the edit summary. Check the revisions page.   The original edit summary will be retained. A user has to edit the post body, or saving the edit summary silently fails.


Why do ISP's offer faster download speeds than upload speeds?

In most cases (in the USA) the major ISP's offer moderate download speeds, but the uploads speeds are a fraction of the upload speeds (normally about 10%).    Why is this done?  It would seem better to have the same speed for the upload and download even if this would make the download slower.  Is the ISP's infrastructure set so that more is dedicated to downloads as that is what more people in the world use?


Does the likelihood of an event increase with the number of times it does not occur?

I would seem logical that the more times an event does not happen, the more likely it is to happen, for example: If a coin is flipped and it lands on tails 10 times in a row it would seam more likely that the next flip will result in heads.  The Infinite Monkey Theorem is one such idea that suggests this is true,   It states that if some number of monkeys are left in a room with typewriters for an infinite amount of time then they will eventually compose all written texts ever produced.  This seems to suggest that since the chance of the monkeys writing a work, say Shakespeare's Romeo and Juliet, is very low. The more times they do not write it, the more likely they are to write it, until the chance becomes significant and it, the writing of the play, happens.  However another idea, Gambler's Fallacy states quite the opposite.   It states that the chance of an event does not increase with the number of times it does not occur.  So what is the answer? Does the likelihood of an event go up the more times it does not happen, or does it stay the same? And if it does stay the same then how does one explain the Infinite Monkey Theorem?


Is there a word for the use of period after each word of a sentence grammatically correct?

I have seen statements like the one below which make deliberate use of full stops after each word of the sentence:    Is there a single word for such a statement?


90s-2000s sci-fi book: detective that travels to an alternate world that is first viewed from an airplane

I think this book was written in the late 90s to early 2000s by a male writer.   The detective is hired to find a guy who he eventually finds. Maybe the guy he was looking for was a scientist? The detective gets into trouble along the way and is saved by cats. He somehow wakes up at a hotel run by cats. Regular cats. He wonders how it gets maintained. I think he has a cat.  He has a friend who somehow gets lost in a dangerous part of this alternate world and his friend is killed by a memory of his own mother come to life.  The end of the book is when the reader finds out the world as we know it exists and this is an alternate world that he or maybe someone else (I don't remember) saw the landscape of from an airplane.


When i try to click on the button several time then i encountered this error. Below are the error in logcat: E/AndroidRuntime: FATAL EXCEPTION: main     Process: com.example.huiiy.myapplication, PID: 3933     java.lang.NullPointerException: Attempt to invoke virtual method 'void android.media.MediaPlayer.start()' on a null object reference         at com.example.huiiy.myapplication.Activity9$13.onClick(Activity9.java:288)         at android.view.View.performClick(View.java:5712)         at android.view.View$PerformClick.run(View.java:22514)         at android.os.Handler.handleCallback(Handler.java:751)         at android.os.Handler.dispatchMessage(Handler.java:95)         at android.os.Looper.loop(Looper.java:154)         at android.app.ActivityThread.main(ActivityThread.java:6141)         at java.lang.reflect.Method.invoke(Native Method)         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)  Below are the coding of my application:     iv_33.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View view) {             MediaPlayer ivbsound = new MediaPlayer();             ivbsound = MediaPlayer.create(Activity9.this,R.raw.ivbutton);             //          MediaPlayer ivbsound = MediaPlayer.create(Activity9.this,R.raw.ivbutton);             ivbsound.start();             int theCard = Integer.parseInt((String) view.getTag());             doStuff(iv_33, theCard);         }     });


How to calculate index PE ratio using individual stocks PE ratios, Is there any way to do it?

We know there are multiple types of indexes like market cap weighted and equal weighted indexes, etc., Currently am working on S&P 500 and is there any way to calculated PE ratio for S&P 500 using PE ratios of individual companies.  if we have EPS, no. of shares outstanding and market capital for all the stocks then we can calculate, but is there any way to calculate in the above process.  with the help of below wiki link    Weighted Index P/E= market capitalization/net income Market cap = market price x current number of shares Net income = EPS x weighted average number of shares


How should a physics student study mathematics?

Note: I will expand this question with more specific points when I have my own internet connection and more time (we're moving in, so I'm at a friend's house).  This question is broad, involved, and to some degree subjective.  (I started out as a physics-only student, but eventually decided to add a mathematics major. I am greatly interested in mathematics; the typical curriculum required for physics students is not deep or thorough enough; mathematics is more general (that means work!); and it only requires a few more classes. Naturally, I enjoy  immensely.)  This question asks mainly of undergraduate-level study, but feel free to discuss graduate-level study if you like.  Please do not rush your answer or try to be comprehensive. I realize the StackOverflow model rewards quick answers, but I would rather wait for a thoughtful, thorough (on a point) answer than get a fast, cluttered one. (As you probably know,  produces clear, useful writing; and a properly-done comprehensive answer would take more than a reasonable amount of time and effort.) If you think an overview is necessary, that is fine.  For a question this large, I think the best thing to do is focus on a specific area in each answer.    Update: To Sklivvz, Cedric, Noldorin and everyone else: I had to run off before I could finish, but I wanted to say I knew I would regret this; I was cranky and not thinking clearly, mainly from not eating enough during the day. I am sorry for my sharp responses and for not waiting for my reaction to pass. I apologize.  Re: Curricula:   Please note that I am not asking about choosing your own curriculum in college or university. I did not explicitly say that, but several people believed that was my meaning. I will ask more specific questions later, but the main idea is how a physics student should study mathematics (on his or her own, but also by choosing courses if available) to be a competent mathematician with a view to studying physics.  I merely mentioned adding a mathematics major to illustrate my conclusion that physics student need a deeper mathematical grounding than they typically receive.   And now I have to run off again.


What is the terminal code for adobe flash?

What is the terminal code to download the latest adobe flash player on linux 16.04?


Avoiding NullPointerException while checking for possible-null object (Java)

public boolean hasCapturableEnemy(Piece[][] board, int startX, int startY) {      //If the Pawn belong to the Upper Team (Faces downward)     if(board[startX][startY].getTeam() == Player.UP) {          //If a Piece exists diagonally in front of it on an adjacent tile, return true         if((board[startX - 1][startY + 1].getTeam() != Player.UP) || (board[startX - 1][startY - 1].getTeam() != Player.UP)) {             return true;         } else {             return false;         }      } else { //If the Pawn belongs to the Down Team (Faces upward)          //If a Piece exists diagonally in front of it on an adjacent tile, return true         if((board[startX + 1][startY + 1].getTeam() != Player.DOWN) || (board[startX + 1][startY - 1].getTeam() != Player.DOWN)) {             return true;         } else {             return false;         }     } }   I built a boolean function that tries to check if a Pawn chess piece has an enemy to capture. On the condition of checking whether the piece on the diagonal side of the Pawn is an enemy or not, I get a NullPointerException since I am checking for both diagonal position and one of them could be an empty location (null).  (board[startX + 1][startY + 1].getTeam() != Player.DOWN)  //This could be NULL   How can I avoid getting a NullPointerException while checking for both position and checking their member variable (Team) ?


why should we use if( $_SERVER["REQUEST_METHOD"] == "POST")

I am watching a video about PHP form submit, it mentions this method   if ($_SERVER["REQUEST_METHOD"] == "POST") { /* code handle the form date */ }   I don't know why we should use that? Can someone explain for me? Thanks!


Do individual rays of light lose energy via the inverse square law?

We've all heard of the inverse square law, but apparently that refers to the flux or intensity or number of photons hitting an imaginary surface area. This is not exactly what I want to ask about.  I'm asking about the energy level of an individual photon, or individual ray of light. The light could be any frequency or wavelength.  If I'm not mistaken, the amplitude of the light ray is directly related to its energy.  Consider a ray of light travelling through a vacuum. Does its energy decrease over time according to inverse square law? Maybe inverse linear? Or not at all?  This question comes from . If it's true that the energy doesn't diminish at all, then that would mean a laser beam shot into space (and never hits anything) would never lose any energy and arrive at the other side of the Universe with the same energy it started with. That's kinda hard to believe.  EDIT: It appears "energy" and "amplitude" are not synonyms for light rays. Apparently the concept of waves is tricky for light, since after all, a vacuum has no medium to propagate through in the normal wave sense. So let the question be, "Does an individual photon lose energy solely from the act of traveling through a vacuum?"


I'm struggling to restore backups from an older installation of Ubuntu to a new installation on Ubuntu 16.04. I get the following error when trying to restore:  Failed with an unknown error Followed by:  Traceback (most recent call last):   File "/usr/bin/duplicity", line 1532, in <module>     with_tempdir(main)   File "/usr/bin/duplicity", line 1526, in with_tempdir     fn()   File "/usr/bin/duplicity", line 1380, in main     do_backup(action)   File "/usr/bin/duplicity", line 1461, in do_backup     list_current(col_stats)   File "/usr/bin/duplicity", line 698, in list_current     for path in path_iter:   File "/usr/lib/python2.7/dist-packages/duplicity/diffdir.py", line 354, in combine_path_iters     refresh_triple_list(triple_list)   File "/usr/lib/python2.7/dist-packages/duplicity/diffdir.py", line 341, in refresh_triple_list     new_triple = get_triple(old_triple[1])   File "/usr/lib/python2.7/dist-packages/duplicity/diffdir.py", line 327, in get_triple     path = path_iter_list[iter_index].next()   File "/usr/lib/python2.7/dist-packages/duplicity/diffdir.py", line 239, in sigtar2path_iter     for tarinfo in tf:   File "/usr/lib/python2.7/tarfile.py", line 2508, in next     tarinfo = self.tarfile.next()   File "/usr/lib/python2.7/tarfile.py", line 2350, in next     raise ReadError("unexpected end of data") ReadError: unexpected end of data   The backup completed successfully but I cannot get it to restore.  Thanks in advance!


How do I wire a 380v/3 phase bench grinder to run on 220v single phase

I acquired an old factory bench grinder. It's a 380/220 3 phase 50 Hz unit. Can someone explain how to wire this to run on single phase 220 V (household power)?  I tried simply connecting the blue and brown leads to a 220 V outlet and spinning the unit by hand but that didn't work. I can hear the motor getting power, but it won't spin up.       Click images for full-size view.


Integrating $\int^0_\pi \frac{x \sin x}{1+\cos^2 x}$

Could someone help with the following integration:   $$\int^0_\pi \frac{x \sin x}{1+\cos^2 x}$$  So far I have done the following, but I am stuck:  I denoted $ y=-\cos x $ then: $$\begin{align*}&\int^{1}_{-1} \frac{\arccos(-y) \sin x}{1+y^2}\frac{\mathrm dy}{\sin x}\\&= \arccos(-1) \arctan 1+\arccos 1 \arctan(-1) - \int^1_{-1}\frac{1}{\sqrt{1-y^2}}\frac{1}{1+y^2} \mathrm dy\\&=\frac{\pi^2}{4}-\int^{1}_{-1}\frac{1}{\sqrt{1-y^2}}\frac{1}{1+y^2} \mathrm dy\end{align*}$$  Then I am really stuck. Could someone help me?


I just got an iPhone5S and want to use an mp3 I have in My Music as a ring tone.  How can I do this. The manual only seems to talk about purchasing tones.  EDIT I have made a 40 second m4r file and it is in My Music on the iPhone, but I can't find it in Ringtones.  I cannot find  "Sync Ringtones" in the phone sync options.


How do I create a package of fonts? I am not going to be uploading them to the Archive as they are for my own use.    Can anyone point me to a tutorial or a document on creating font packages?  I have managed to create a wallpaper package using dpkg-deb but I have a feeling that I need to do something more as I would need to run fc-cache as well.    I do not have the source files to these fonts as I have just downloaded them from the web so I'm not sure how to proceed.


Gap between line and point in pgfplots, like pointintervalbox in gnuplot

I wondered if it is possible to create a scatter plot in pgfplots with a similar style as the "pointintervalbox" option in gnuplot, i.e. a plot with points and lines, but there is a gap between the lines and the points.  Here is an :    Maybe something like this already exists but I couldn't find it because I don't really know how to describe it.  Thank you


Change pgfplots markers colors and shape

In my MWE below, I am not getting the markers of the plots to colors that I wanted.  Also, I would like to change the red squares in the last plot to cyan circles.  Thanks.  Here is my code:  \documentclass{book} \usepackage{tikz} \usepackage{pgfplots} \usepackage{filecontents}  \begin{filecontents*}{data.csv}   Iter   Abs1   Abs2      x      y      1, 0.9317521, 1.1849326, 1.6130556, 0.8022207      2, 1.8946202, 1.1228282, 1.8964566, -0.5353802      3, 1.5243302, 1.0372991, 1.4375012, 0.9719003      4, 1.5797030, 1.1346832, 1.8717142, 0.3138737      5, 1.8814457, 1.0529187, 2.0568468, -0.5509391      6, 2.0435003, 1.0470546, 2.0621956, -0.3565483      7, 2.0373926, 1.1215579, 2.1836100, 0.3360301      8, 1.9797077, 1.1632352, 1.8299063, 0.3871091      9, 1.9972528, 1.1952478, 1.8133509, -0.0867033     10, 1.8320176, 1.0625633, 1.0727495, 1.7256738 \end{filecontents*}  \begin{document} \begin{tikzpicture} \begin{axis}[width=14cm,height=8cm, title = {\emph{(a) $P_{T}$ over different samples}}, xlabel={$x~Position$},ylabel={$y~Position$}]  % Graph column 2 versus column 0 \addplot+ table[x index=3,y index=4,col sep=comma, only marks,mark=*,mark options={scale=2, fill=white}] {data.csv}; %\addlegendentry{Column 3}% y index+1 since humans count from 1  \end{axis} \end{tikzpicture}  \begin{tikzpicture} \begin{axis}[width=14cm,height=8cm, title = {\emph{(b) RSLE Parameter Errors in terms of Recursions RSLE}},xlabel={$Number~of~Recursions$},ylabel={Absolute Parameter Error}]  % Graph column 1 versus column 0 \addplot table[x index=0,y index=1,col sep=comma, green, only marks] {data.csv}; \addlegendentry{$\delta_{r2}$}  % Graph column 1 versus column 0 \addplot table[x index=0,y index=2,col sep=comma, cyan, only marks] {data.csv}; \addlegendentry{$\delta_{r3}$} \end{axis} \end{tikzpicture}  \end{document}


How the AmE speakers call a building's apartment

What do the AmE speakers call the apartment number 13 in a building which has e.g. 20 apartments when they are mentioning to their postal address: Apartment / unit 13 - No 10 - Harvard street - Massachusetts - United states  1) Apartment 13 2) Unit 13


Converting a 9v Battery powered Device to a 9v dc power supply

I have an old Vivanco MX300 mixer which runs of a 9v battery.  I have it in the same place and it's an inconvenience having it run by batteries. Could I use an old AC/DC adapter that would supply 9v at 1A or will it blow my desk.


I don't know which is correct, it seems both can be used?  "The above gun shows..." or "the gun above shows.."  Also the below gun or the gun below, which is correct?


How to restore SQL Server database to a particular time?

Is it possible for me to restore a SQL Server 2019 database up to a particular datetime? The database backup is full backup. The database is full recovery mode, and only one transaction log backup after the full backup. Thanks.


I have a file named file.txt with some contents located in /home/myuser directory and I change the permissions of that file to root.root and 644.   -rw-r--r-- 1 root root 1.4K Jan 15 07:09 file.txt   Then I switched to myuser and opened it with vim(without sudo) and tried to edit and save it :wq! and I got output like:  "file.txt" E949: File changed while writing Press ENTER or type command to continue   Then I hit enter and then again :wq! and the output was :  WARNING: The file has been changed since reading it!!! Do you really want to write to it (y/n)?   I hit y, the file got saved and exit from vim.  The question is why a file with ROOT privileges and read-only access for a user changed by the way?  PS: 1. myuser is a sudo user.   The user permissions after saving the file changed to myuser.myuser as well.  -rw-r--r-- 1 myuser myuser 1.4K Jun 27 18:57 file.txt


I do not know what ~$ or /$ mean in terminal. But, I really need to change my terminal from ~ to /. To change a folder permission, for putting a php file in var/www/html. Maybe there is an easy way to change ~ to / in terminal.


Evaluating power series on the radius of convergence for $\tan^{-1}(x)$

Suppose that I know the series for $(\tan^{-1})'=\sum_{n=0}^{\infty} (-1)^nx^{2n}$ converges when $\lvert x\rvert \lt 1$.   Then I know that $$\tan^{-1}(x)=\sum_{n=0}^{\infty} \frac{(-1)^nx^{2n+1}}{2n+1}$$ only for $\lvert x \rvert \lt 1$.   My professor asks me:   How do I know that $$\lim_{x\to\ 1}\sum_{n=0}^{\infty} \frac{(-1)^nx^{2n+1}}{2n+1} = \sum_{n=0}^{\infty} \lim_{x\to\ 1}\frac{(-1)^nx^{2n+1}}{2n+1}\;?$$  In general, once the radius of convergence has been found for a power series, I think I can rest assured the series obtained by differentiating or integrating term by term has the same radius of convergence. What more do I need to consider to talk about the points on the radius?


An Introduction to Theory of Groups by Joseph J. Rotman - Exercise 1.5

If $1 \leq r \leq n,\;$ then there are $\quad\dfrac{n(n-1)\cdots(n-r+1)}{r}\quad r$-cycles in $S_n$.   I think that I used induction to prove this, but I don't know how to prove this. Thanks in advance!


Will the downloadable Windows 10 ISO support an OEM license?  I have all the parts to build a computer but the only thing that didn't come in was the OEM disc.  If I load windows from the downloadable ISO, will it accept the key from the disc once it comes in?


Use .htaccess to prevent image hotlinking except for Google, Bing, Yahoo, and Facebook

Can anyone create a .htaccess hotlinking rule for me allowing Google all domains (.com, co.uk, co.in, .au etc.) + bing.com + yahoo.com + facebook.com  I would do it using online hotlink htaccess generators, but in this case I have to individually add all google domains which is very time consuming. If there is any way rule in which any domain containing .google. are allowed to hotlinking, that might be better.


Is it legal to sell or monetize games created with the Unity 3D free edition?

Is it okay to use Unity 3D programming and gaming software to create mobile game apps for Android and iOS? I am using a free version of Unity 3D and planning it to sell my current game app I've created by publishing it to Google Play. I also use this method for earning money by setting as a free app with ads on it.   I saw some developers relied on using free version of Unity 3D to create games and published it via App Store or Google Play. If it does, should I have to pay or share contribution to the Unity development team for earnings since I use the free version in order to rely for producing several game apps for business?


What's the name of book where copies of people are beamed to other planets?

Does anyone know the name of this book (might be a series)?    Planets are colonized by people having copies of themselves beamed to the planet.  A person walks into a booth on earth for a few minutes and then goes about their life. On the other planet a copy walks out with all the memories of the original.   The story line was about how the lives evolve differently and the same limited number of people keep bumping into "themselves." I think I read it in the 70's but think it is older.


Stack Exchange app iPhone X optimization

The Stack Exchange app doesn’t look very good on Apple’s brand new flagship phone yet.    Also the app can’t identify the device model either. (Says Unknown (iPhone 10,3))   App Version: 1.6.6.2 Device: iPhone X (iPhone10,3) OS Version: Version 11.1 (Build 15B93)


What is the affected space for the area of Burning Hands?

Burning hands states:     As you hold your hands with thumbs touching and fingers spread, a thin sheet of flames shoots forth from your outstretched fingertips.    However, it goes on to affect a cone with a 15 foot diameter base (which is certainly not a thin sheet).     Each creature in a 15-foot cone must make a Dexterity saving throw   What area can actually affect creatures, the thin sheet or the cone? Is it different for objects?     The fire ignites any flammable objects in the area that aren't being worn or carried.   For a use case: Does a tiny creature flying 10 feet away and 10 feet in the air get hit by the 5 foot tall caster's straight burning hands? Does the carpet below catch fire?


Questions with lots of long tags are cut off in the android app

For example this one,  (only just though)  Questions with many long tags get cut off the edge of the screen (on my Galaxy S2).  I think they should wrap to the next line.


This may have more to do with detecting operating systems, but I specifically need the init system currently in use on the system.  Fedora 15 and Ubuntu now use systemd, Ubuntu used  to use Upstart (long time default until 15.04), while others use variations of System V.  I have an application that I am writing to be a cross-platform daemon.  The init scripts are being dynamically generated based on parameters that can be passed in on configure.  What I'd like to do is only generate the script for the particular init system that they are using. This way the install script can be run reasonably without parameters as root and the daemon can be "installed" automagically.  This is what I've come up with:   Search for systemd, upstart, etc in /bin Compare /proc/1/comm to the systemd, upstart, etc Ask the user   What would be the best cross/platform way of doing this?  Kind of related, Can I depend on bash to be on the majority of *nix or is it distribution/OS dependent?  Target platforms:   Mac OS Linux (all distributions) BSD (all versions) Solaris, Minix, and other *nix


The origin and meaning of the word "copacetic"

I looked up  but it appears to have no official origin. Also, what exactly does the word mean, please use it in a sentence.      1919, but it may have origins in 19c. U.S. Southern black speech. Origin unknown, suspects include Latin, Yiddish (Hebrew kol b'seder), Italian, Louisiana French (coupe-sétique), and Native American. None is considered convincing by linguists. (Etymonline)


What is a better way to mark answers as obsolete?

Answers sometimes become obsolete.  New solutions arise that were not technically feasible at the time that the question was originally posed.  People decide that the old way of doing things is no longer a good idea.  This goes for answers on main sites as well as on meta sites.  In , several suggestions were raised, but I don't find them satisfactory.   Deleting is not appropriate, I think, since it removes all trace of the answer, and even obsolete information is sometimes useful.  It leaves a void, and there is even a risk that the void could be filled by someone else writing a similarly obsolete answer.  I also believe that is is inappropriate to strip the original poster of reputation points that were rightfully earned in the past. Editing the answer to provide a new solution is an underhanded approach, since the practice of radically altering posts is prone to abuse.  Who is to say that all the voters who upvoted the original answer agree with whatever new advice is added?  It's even worse if someone other than the original author of the answer violates the author's intent.  Editing also fails to confer reputation commensurate with the effort, if the new answer is completely different.  Additionally, it might not be desirable to bump an old post onto the front page. Downvoting To counteract all of the upvotes, you would have to rally a downvote brigade, which is neither realistic nor desirable.  There's no need to hurt the original poster's reputation just because an answer is no longer relevant.  Furthermore, all previous upvotes are locked in unless the post is edited, so the concerns raised above about editing also apply. Commenting is insufficient, because it could be buried at the bottom of a long thread.  Also, comments on Stack Exchange are designed to be of a somewhat transient nature.  Comments also don't alter the order of presentation of answers. Locking is currently possible only for a "Content dispute" or for "Offtopic [sic] comments".  As the guidelines say, "posts should only be locked when something seriously bad is happening. A locked post cannot be changed in any way or voted on".  I don't think that obsolete information qualifies as "seriously bad", or that editing/voting should be prevented.   I think a feature enhancement is called for!


Eevee rendered image weird frame-edge problem

i'm trying to render a frame and everything looks good besides the upper frame edge that makes the blindfolds window just get cut mid-way.  Anyone have any idea why is this happening?  i've attached a viewport and rendered image.  thanks in advance!


Enumerated list with blue circles and number inside it

I am creating a manual for an application and I would like to provide step by step directions of the application. For the step numbers, I would like to use big, blue circles with white numbers in it. Thus I was thinking if I can modify the bullet style, I would be able to achieve such list. I read few similar questions and it looks like it will have to use the enumitem package and the likes. Probably, there would be a new command for a big circle. I just don't know how to pull everything together.  Example:


When a TV commercial shows for a split second then cuts off, what is happening?

I see this from time to time during commercial breaks: all of a sudden, a commercial will play for a split second, no more than 2 or 3 seconds but then get cut off.  Why does this happen? Is this a time restraint issue?


"a time when you or a relative were/was a patient"

Is the following sentence correct?       Don't be afraid to talk about a time when you or a relative were a patient.    Or should it be one of the following:      Don't be afraid to talk about a time you or a relative was a patient.     Don't be afraid to talk about a time when you were or a relative was a patient.


Why is this sequence of equicontinuous functions uniformly bounded?

Let $\left\{f_{n}\right\}$ be a sequence of equicontinuous functions where $f_n: [0,1] \rightarrow \mathbf{R}$.  If $\{f_n(0)\}$ is bounded, why is $\left\{f_{n}\right\}$ uniformly bounded?


A combinatorial proof that the alternating sum of binomial coefficients is zero

I came across the following problem in a book:  Give a combinatorial proof of  $$ {n \choose 0} + {n \choose 2} + {n \choose 4} + \, \, ... \, = {n \choose 1} + {n \choose 3} + {n \choose 5} + \, \, ...$$ using the "weirdo" method (i.e., where one of the elements is chosen as special and included-excluded -- I'm sure you get the idea).  After days of repeated effort, the proof has failed to strike me. Because every time one of the elements is excluded, the term would be ${n-1 \choose k}$ and not $ {n \choose k}$, which is not the case in either of the sides of the equation.


How to tell how many CPUs (cores) you have on Windows 7

I got me a nice new laptop and I want to know a bit more about the hardware.  How can I see how many CPUs my computer has in Windows 7?  (Note: Clicking on Start → right clicking on Computer → selecting properties shows me the processor type, but it does not say anything about the core count.)


Why did this happen to Thanos's ships at the end of "Avengers: Endgame"?

At the end of Avengers: Endgame, when Tony Stark       snaps the Infinity Gauntlet v2, all of Thanos's ships also get disintegrated. The Chitauri Leviathans are living beasts, so it makes sense, but the  are clearly mechanical, as seen in Avengers: Infinity War.   We did not see this with the snap in Avengers: Infinity War, where      only living things were dusted.   Why is it different this time around?  See 2m35s of , ignore the Chitauri Leviathan in the foreground.


If $M$ is a compact manifold and $X$ is a vector field in $M$ then $X$ generates a flow.  I know that every flow generates a vector field regardless of whether the manifold is compact or not. But I don't know how to try what I want, any suggestions? Thank you.  Edit: I know that if $M$ is a manifold and if $H$ is a local flow on $M$, then there is an induced vector field, which is defined as $X(p)=\frac{d}{dt}|_{t=0}H(t,p)$. What I want to do is prove something contrary to that, I want to prove that if $M$ is a compact manifold and if $X$ is a vector field in $M$, then there is a flow $H$ in $M$ such that $X(p)=\frac{d}{dt}|_{t=0}H(t,p)$, that is what I want.


I have a macro to hide a few columns that shows additional information however i can't get it to unhide the same data. I know it's simple I am just really unfamiliar with Macros. Any help would be awesome! Here is the Macro I use to hide the columns.    Sub Unhide() ' ' Unhide Macro '  '     Columns("C:K").Select     Range("C2").Activate     Selection.EntireColumn.Hidden = False End Sub   I also use this Macro   Sub Hide_E() Dim LastRow As Long, c As Range Application.EnableEvents = False LastRow = Cells(Cells.Rows.Count, "E").End(xlUp).Row On Error Resume Next For Each c In Range("E1:E" & LastRow)    If c.Value = "N/A" Then         c.EntireRow.Hidden = True     ElseIf c.Value = 1 Then         c.EntireRow.Hidden = False     End If Next On Error GoTo 0 Application.EnableEvents = True End Sub   Would it be possible to add a similar code to unhide the rows I hid?   Thank you so much!!


Condensed matter physics: the concept of holes

Is it possible to see an analogy between the holes and positron particle behavior? The holes are particles that behave oppositely to the electron in current conduction.  So it is not the electron which the same behavior of holes. Positron is just the antiparticle of the electron that has same positive charge. In what way do these two concepts differ ?


We know that if $A$ is a PID, then we can guarantee the existence of a $\gcd$ between two elements. My question is, does the converse hold? If I know that every two elements have a $\gcd$, do I know that the ring is a PID? My intuition says no, in that case I would like a counter-example.  Thanks.


Question on Groups $G=\langle x,y|x^4=y^4=e,xyxy^{-1}=e\rangle$

Studying for an exam, a review question...  Given $G=\langle x,y|x^4=y^4=e,xyxy^{-1}=e\rangle$.    Show $|G|\leq16$.   For this, I want to consider that $x^3=x^{-1}$ and $y^3=y^{-1}$ based on our assumptions. I am a little lost as to how to put the second part, $xyxy^{-1}=e$ to show there are no more than 16 elements.   If $|G|=16$, find the center of the group and find a group that is isomorphic to $G/\langle y^2\rangle$.   I'm pretty sure the group is centerless.


Bash script -ne comparison giving "command not found" error

In my bash script I wish to ssh into a machine, and if the machine is down, perform something within an if statement.   To check whether or not the the machine is down I have an if statement using the -ne command which I use to compare the value returned by the ssh function ($? which is 255 if the ssh was unsuccessful) and 0.   However I get the following error  line 5: [0: command not found   Here is my code  #!/bin/bash  ssh blobbby  if [0 -ne $?] then     echo "ssh not succesful" fi   If someone can please explain what mistake I've made I would be most grateful.


What exactly happens when you browse a website in your browser?

What happens behind the scenes when we type www.cnn.com in a browser and how does information gets displayed on the screen?   A technical explanation would be highly appreciated.


Mobile chat "you have been suspended" notification is too ambiguous

Earlier today, I was suspended from chat due to an inappropriate message (I totally deserved it, but that's not the point). I looked at my phone, and this is all that it told me:    ...which confused me because chat was still moving as normal. I didn't realize that I had been suspended until I checked on my computer to see what the heck was going on.  To me, "This room is read-only" sounds like some sort of database lockup or something related specifically to the room, not the user. It doesn't give any feedback to indicate that the room will be "read-only" for 30 minutes, and doesn't mention that all other rooms are also "read-only". Even a message saying just "You have been suspended from chat" would be more helpful.


Where does homebrew download software from?

I love how homebrew makes my life easier! Though, I just realized that I don't really know who is "signing off" the stuff I get installed through it. So, I ask:    Is there a central repo (like Linux distro PPAs)?  Or is it all decentralized (ie. code gets downloaded simultaneously from Github, Source Forge, etc)? What mechanisms are in place to prevent trojan horses from being installed through brew?


Appropriate management and supervision of tourism centers "is" or "are" essential?

Which one is correct and why?   Appropriate management and supervision of tourism centers is essential. Appropriate management and supervision of tourism centers are essential.


'Relocation Offered' tag is not providing any information. I understand it includes moving expenses but does it include visa too?   This question is different from    , and      because I want to know how to find out visa sponsorship details? Is it implicit or we need to ask company explicitly in application.  Is it that only way to find if company is interested in sponsoring visa only by applying them?


In debian wheezy terminal I type  su -   It ask for password, which I type but it doesn't show anything as  Password:   I want to it to show at least some asterisks as the placeholder for the password characters as follow:  Password: ************


Windows Script Host Error Dialog Popups in the morning

A few days ago when I resume my computer from sleep mode in the mornings I would see an error dialog from "Windows Script Host" that read: "There is no script engine for file extension ".vbs". I am having hard time tracking down the source of this. I've looked through the event log, registry, and the scheduled tasks. But the lists are so long and I don't know where exactly to look for.   Details: It looks like it happens once a day and I only see it in the mornings. I'm on 64-bit Windows 7 Home Premium.  Any pointers are appreciated.  also, i think this started after one of those automatic windows updates.


Constructing a contradiction to prove limit of a recurrence relation

Let  $$ \Delta P = (b-P_n)/2 \\ P_{n+1} = P_n + \Delta P\\ P_n : \mathbb{Q} \to \mathbb{R} $$ We shall attempt to prove that  $$ \lim_{n \to \infty} P_n = b $$ I'll try in three parts   $P_n$ is monotonic $P_n$ is bounded by $b$ Something along the lines of $\sup P_n = b$   First, prove $P_n$ is bounded by $b$. Assume the contrary by taking $P_n$ to be the supremum of $P_n < b$ and therefore $P_{n+1} > b$. Now that implies $\Delta P > b-P_n$ which violates the definition of the recurrence. Therefore, $P_n$ is bounded from above by $b$  Second, let us prove that $P_n$ is monotonic with respect to $n$. Assuming $b > P_0$, $P_1 > P_0$. Now choose an arbitrary $P_{n}$, where $b > P_n$ from the previous result. If $P_{n+1}  = P_n + \Delta P$, $\Delta P = \frac{b-P_n}{2} > 0$ and therefore $P_n$ is increasing for $P_n < b$  Now let us prove that $\lim_{n \to \infty} P_n = b$.  That means that for all $M, \epsilon > 0$  $$ n > M \implies |P_n - L| < \epsilon $$ To start, we know $L \le b$ by our first result.   Now all we must prove is that $L < b$ is impossible, which is what I am having trouble with.   What I am having trouble with  Well if for all $n>M$, $P_n < L$ then for all $P_n$, $$ \Delta P  =  \frac{b-P_n}{2}< L-P_n < \epsilon $$ I'm having trouble constructing a contradiction and was hoping for some help doing so.   I specifically want to use a delta epsilon proof and not any other form of proof.


What is necessary to confirm business ownership and income for UK visa application?

How can a business confirmation letter be written if person is owns the business? What are the sources required if I already provided information that it's the business inward cash sales transactions?


What access modifiers should be use behind the class keyword and why?

I understand the way the four access modifiers work inside classes, however you can also put them before the keyword class, like: accessModifier class className{  accessModifier type var; }  I previously understood access modifiers as the members' visibility, so, e.g., private would mean the variable will only be visible inside the class; but how does that work behind the class? Also, in what situations should I put the access modifiers behind the class and why?


Do spell targets know they were targeted?

Assuming a target of a Pathfinder spell did not see/hear/notice a caster casting the spell, do they know/feel they were targeted?  Is it relevant if the spell worked or not, if a save was involved (either successful nor not)? Does it depend on the spell?  Example: A cleric casts detect evil through a door. What do the NPCs on the other side know now?


How to redirect stdout and stderr in desktop entry?

I put a .desktop file in ~/.config/autostart:  [Desktop Entry] Type=Application Exec=sslocal >log 2>&1 Path=/etc/shadowsocks Hidden=false NoDisplay=false X-GNOME-Autostart-enabled=true   Though sslocal ran as expected, it didn't generate log file.


I spend my days waiting on the Force.com Console and it makes me crazy, I have a pretty nice machine and it still chokes on the details sometimes.  Anyways, I saw  had given a  and is presenting again this year Dreamforce '12.  However, it seems like they're presentation is targeted at using their product, or for that matter others like it (, ) on Heroku, and not really targeting APEX/VisualForce development!  Is this the case? Are there any better solutions out there for reviewing logs?  Are there any APIs that allow you to export your debug logs out of SFDC programatically? Or has anyone even tried to tackle this?


pyproj does not properly convert EPSG:3760 to WGS 84

I have coordinates stored in EPSG:3760. I can use  to transform these properly to WGS 84 GPS coordinates, like so:    As seen in the photo, my coordinates (1728779.950564162, 81827.07350218101) are successfully converted to GPS (-157.7402677, 21.3917278). I have verified these coordinates using a map.  Trying to use pyproj, however, gives me a different result.  >>> import pyproj >>> pyproj.__version__ '1.9.5.1' >>> >>> p1 = pyproj.Proj(init='epsg:3760') >>> p2 = pyproj.Proj(init='epsg:4326') >>> >>> x = 1728779.950564162 >>> y = 81827.07350218101 >>> >>> pyproj.transform(p1, p2, x, y) (-146.20443693009113, 21.483194748289176)   Why is pyproj giving me different and inaccurate results?


I have a requirement to read and display the owner of a file (for audit purposes), and potentially changing it as well (this is secondary requirement). Are there any nice C# wrappers?  After a quick google, I found only  and a suggestion to PInvoke GetSecurityInfo


In python I can add a method to a class with the @classmethod decorator.  Is there a similar decorator to add a property to a class?  I can better show what I'm talking about.  class Example(object):    the_I = 10    def __init__( self ):       self.an_i = 20     @property    def i( self ):       return self.an_i     def inc_i( self ):       self.an_i += 1     # is this even possible?    @classproperty    def I( cls ):       return cls.the_I     @classmethod    def inc_I( cls ):       cls.the_I += 1  e = Example() assert e.i == 20 e.inc_i() assert e.i == 21  assert Example.I == 10 Example.inc_I() assert Example.I == 11   Is the syntax I've used above possible or would it require something more?  The reason I want class properties is so I can lazy load class attributes, which seems reasonable enough.


Why is a .bak so much smaller than the database it's a backup of?

I just took a backup of a SQL Server database.  The MDF and LDF files together total around 29 GB, but the .bak file was only 23 GB, about 20% smaller.  My first guess when one version of a set of data is smaller than another version containing the same data would be data compression, but compression usually yields a much better compression ratio than 20%, especially for highly-ordered data (such as database tables.) Also, compressed data can't easily be compressed further, but I know that .bak files can be compressed.  So if the data isn't being compressed, and nothing's being discarded, (because the whole point of making a backup is to be able to restore it to an identical state afterwards,) then what's that 20% that's unaccounted for?


Headings change influence the caption formatting (srcreprt)

I had to change the headings (chapter, sections, subsections...) for a journal to get a final point after the last number. Example:  1 My First Chapter  1. My first Chapter   Therefore, I added the following stuff to my preamble:  \renewcommand{\thechapter}{\arabic{chapter}.} \renewcommand{\thesection}{\thechapter\arabic{section}.} \renewcommand{\thesubsection}{\thesection\arabic{subsection}.}   The problem that I have now is, that the captions of the figures and tables, and also the references are not correct anymore because I got the additional point:  \caption{Evaluation of the arbitrary temperature profiles on $n$ random points (red)}   Will be displayed as:     Figure 2..2: Evaluation of the arbitrary temperature profiles on n random points (red)   As you can, I got the additional point between the numbers, which comes from the added lines above. Based on the feedback I got, I checked out the following thread:  , which is finally what I am searching for but the commands:  \titlelabel{\thetitle.}   Is not working within my class (scrreprt}. Doing so, I get the error message:     Undefined control sequence \section{Latex}   At the moment I do not know how to change this behavior. Any suggestion is warmly welcomed.   By the way, to all supporters and volunteers, you do a really great work.!


How to maintain interlink between multiple enums in c#

I'm new to c#, in java we used to have interlinking for enums like below:   public enum Module {     None(SubModule.None),     Authentication(SubModule.Login),     User(SubModule.User,SubModule.ForgotPassword,SubModule.ResetPassword)       private SubModule subModule;      public Module(SubModule... submodule)     {      }   }   I want to interlink my Modules with submodules, I tried the same in C# its giving compilation error. Is there anyway to do the same in C#.


Javascript named function as an expression

Javascript Code  var d = function c() { console.log(c); }; d(); // function c() { console.log(c); };  c(); // Reference Error   I understand the concept of variable hoisting where variable declarations and function definitions are hoisted to top of the existing scope. Also function definition in function expressions are not hoisted.   So, above will be  var d; d = function c() { console.log(c); }; d(); c();   Hence d is a reference to a named function c   on executing d() the function c is executed in global scope, where there is no variable or property named c. But still console manages to log function definition of c.  When I tried c() I got a reference error. [As I Expected]   Case 2 proves that there is no window property named c available So, How did d() manage to print the c's definition on execution?   Does every function have its own definition in its local scope as a property?


Comparing Eigenvalues of Positive Semidefinite Matrices

If $B\succeq A$, show that $\lambda_n(B)\ge\lambda_n(A)$, where $\lambda_n$ is the $n$th largest eigenvalue.  It is Theorem 6 in  but the proof is only given as "by characterization." Do they mean the min/max characterization of eigenvalues, $$\lambda_k=\min\max\frac{x^TAx}{x^Tx}$$ and if so, how is that applied?  Thanks.


I have a STM32WB55CGU6 where I have all my ADC pins used up and im trying to obtain the battery level using a pin which does not have a ADC (PB6) which is branched as shown in the picture:    This follows the principle where it will charge and discharge  following this link :   This is my current program but somehow it doesnt work and im pretty sure im doing something wronf but what I am not too sure.  while(1){       HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_SET);        HAL_Delay(1);       HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_6);       while(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_6)==1){           time++;       }       if (HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_6)==0){value = time;} }   Im programming with STMCubeIDE where I have set the pin to GPIO_Analog


Let $a,b$ be two group elements of finite order that commute.   What can be said about the order of $ab$?   I thought that $|ab| = \text{lcm}(|a|,|b|)$. My proof was that $(ab)^n = a^n b^n =e$ if and only if $a^n = b^n = e$ if and only if $|a|,|b|$ both divide $n$. The smallest $n$ such that both orders divide it is the least common multiple of $|a|$ and $|b|$.  By chance I came across . It has an upvote so it's clearly correct. (?)  But it contradicts what I think: It's clear that   $$ (ab)^{\text{lcm}(|a|,|b|)} = e$$  hence $|ab| \mid \text{lcm}(|a|,|b|)$.  It seems to me that this is saying more than $|ab| \mid |a| |b|$. Is it not?     Now my question is: what is the precisest statement that can be made about $|ab|$?  Is there anything more than $|ab| \mid \text{lcm}(|a|,|b|)$ that can be said about $|ab|$?


Constant Presheaf on Irreducible Space already a Sheaf

Let $X$ be a space, $U \subset X$ an open subset and let $\mathbb{Z}_U$ the constant presheaf on $X$ defined via  \begin{equation}   \Gamma(V, \mathbb{Z}_U) =    \begin{cases}      \mathbb{Z} & \text{if } V \subset U, \\      0 & \text{else}     \end{cases} \end{equation}  Generally, $\mathbb{Z}_U$ is just a presheaf, therefore becomes just a sheaf $i_!\mathbb{Z}_U$ after sheafification.   My question is why is $\mathbb{Z}_U$ already a sheaf, if $X$ is irreducible?


Manually give rep to users, to thank them

I recently made  to which I got .  I'm very appreciative of the fact that the user took so much time to write up such a comprehensive answer and would like to give them some of my rep. Granted, he's at 53k rep and doesn't need the little extra he'll get from me, but I still want to show my appreciation; and stalking him to find his address to send him a basket of muffins is a little too creepy, even for me.  Now, I could start a bounty, but there are three problems with doing that:   I'm not looking for a better answer If I were to start a bounty, I'd have to be fair and consider all new answers as well, before awarding it The posted answer has been posted as a community wiki, so I'm not sure that he'd even get the bounty if I awarded it to his post.   So short of reading all his posts that I can understand to upvote him a lot (so he'll get the +5/10 rep for each one), is there a way that I can give him some of my own rep (a la manual bounty award) as a "thank you"? Note that I'd have to be really careful if I choose to go down the serial voting path, so as not to trip the "suspicious voting" script []  PS: I've already looked at  and  and they're not duplicates of this question


How to get the SPD Workflow Instance column name from the document library using PowerShell

I am having a SPD 2010 workflow created and deployed in my site collection and  published globally as a reusable workflow. I have configured the workflow in my document library by associating it with my custom content types.  How will I ensure that the workflow has been triggered successfully using PowerShell?   I have 158 sub sites in my site collection and having 10 document libraries so I can not verify whether the workflow instance been triggered successfully or not in all the document libraries and all sub sites. So I have to write a PowerShell to get the column name of workflow  instance.   How to get the workflow instance column name from the  document library.


Do we need the Axiom of Choice to show that $(\mathbb{R}, +)$ and $(\mathbb{C}, +)$ are group isomorphic?

Under the axiom of choice,  $\mathbb{R}$ and $\mathbb{C}$ are both $2^{\aleph_0}$-dimensional vector spaces over $\mathbb{Q}$. Because they have the same dimension, they are isomorphic as vector spaces. That vector space isomorphism is also a group isomorphism between them.  The proof is clearly non-constructive. Is there a way to explicity construct such an isomorphism, or do we need the axiom of choice?


Ingress hacking streak back to '0' despite definite hacking within 24 hrs

I had a hacking streak (sojourner) of 71 days and did my first hack of the day on day 72 (31 August), only to discover it had gone back to '0'. Why has this happened. I definitely did not miss the 24hr reset time as I was actually out and about 4 hours earlier than I would normally have been. To say I was really annoyed about this is an understatement!


Hover jquery not able to locate my table's rows

I have a table skeleton created in the HTML and then added options based on JSON data in my js. I currently have the rows & options for the table created from that js, so that the data can be dynamic.   Eventually I'd like to have data show/do something after you hover a row. I decided to just try and implement a background-color change for now, to verify it works.   However, I'm running into some issues. It's not able to recognize the different rows inside my table.   Here's a code pen link,   Is this due to how I'm creating the rows & options inside my javascript?  If I change it to look for ".tr", it only finds the header row. If I change it to look for ".tbody", it affects the whole body.  I also tried creating a class when my js appends the tr, which you can see in the code shown here. This provided 0 highlighting.  $(".myRows").hover(   function() {     console.log('hover called');     $( this ).css("background","yellow" );   }, function() {     $( this ).css( "background","" );   } );


Change color in beamer theme to user defined

I would like to change the color of my headings and bullet points from the default blue to my own blue. I have put in the correct rgb (it works with documents like PowerPoint), but somehow my beamer presentation has a different shade of blue than the blue I get in PowerPoint with the same rgb. How can that be? What can I change in my code?  \documentclass{beamer} \usetheme{default} \usecolortheme{default} \definecolor{mine}{rgb}{0,138,171} \setbeamercolor*{palette primary}{bg=mine,fg=white}     \setbeamercolor*{palette secondary}{bg=mine,fg=white}     \setbeamercolor*{palette tertiary}{bg=mine,fg=white}     \setbeamercolor*{palette quaternary}{bg=mine,fg=white}     \setbeamercolor*{structure}{fg=mine} \setbeamercolor*{section in toc}{fg=mine}  \begin{document} \title{My title}   \author{My name} \date{\today}  \begin{frame} \titlepage \end{frame} \end{document}


Does an inseparable extension have a purely inseparable element?

Assume $K/F$ is an inseparable extension. Is it necessary that K contains an element $u \notin F$ that is purely inseparable over $F$?  I also posted in MO.


How to plot ROC curves in multiclass classification?

In other words, instead of having a two class problem I am dealing with 4 classes and still would like to assess performance using AUC.


Able to answer closed question if I was offline when the question was closed

On the RPG stack exchange, this question specifically:   I was able to answer the question 10 minutes after it had been closed.  I had begun typing my answer before the question was closed, but during the time that the question was closed, my laptop was hibernating while I relocated to a different room. When I brought it back up, the question gave no indication that it was closed, and it accepted my answer when I submitted it.  Assuming the Stack uses sockets to communicate with machines, it appears that, on a Socket Reconnect, updates are not being pushed and there is no second-level check on the server before accepting an answer.


How do I change the default browser that konsole opens URLs with?

I have google-chrome set as my default web browser in Ubuntu and gnome applications.   However, when using konsole, all links open in konqueror, and not google-chrome!  I've tried setting the default browser with: sudo update-alternatives --config 'x-www-browser'  This works for opening links in gnome-terminal, and other gnome programs... but not kde ones like konsole.  Also, there appears to be no kcontrol program for accessing the kde settings.  Does anyone know a way to set the kde setting for this while still using gnome?  EDIT: From what I can tell, I've got all the related settings configured that I can think of...  grep 'chrome' ~/.local/share/applications/mimeapps.list  x-scheme-handler/http=google-chrome.desktop;firefox.desktop; x-scheme-handler/https=google-chrome.desktop;firefox.desktop; x-scheme-handler/http=google-chrome.desktop x-scheme-handler/https=google-chrome.desktop x-scheme-handler/chrome=firefox.desktop text/html=google-chrome.desktop application/x-extension-htm=google-chrome.desktop;firefox.desktop; application/x-extension-html=google-chrome.desktop;firefox.desktop; application/x-extension-shtml=google-chrome.desktop;firefox.desktop; application/xhtml+xml=google-chrome.desktop;firefox.desktop; application/x-extension-xhtml=google-chrome.desktop;firefox.desktop; application/x-extension-xht=google-chrome.desktop;firefox.desktop; x-scheme-handler/about=google-chrome.desktop x-scheme-handler/unknown=google-chrome.desktop  grep 'chrome' /usr/share/applications/defaults.list  text/html=firefox.desktop;google-chrome.desktop text/xml=firefox.desktop;google-chrome.desktop application/xhtml_xml=google-chrome.desktop x-scheme-handler/http=firefox.desktop;google-chrome.desktop x-scheme-handler/https=firefox.desktop;google-chrome.desktop x-scheme-handler/ftp=google-chrome.desktop   And there are no references to konqueror:  grep -i 'konqueror' /usr/share/applications/defaults.list grep -i 'konqueror' ~/.local/share/applications/mimeapps.list grep -i 'kon' /usr/share/applications/defaults.list grep -i 'kon' ~/.local/share/applications/mimeapps.list


How to force a matrix to be unitary given constraints on some of the elements?

I am working with a matrix of the following form: $$ A =\begin{pmatrix} a_{11} &  Q  & \ldots & Q\\ a_{21} &  Q & \ldots  & Q\\ \vdots & \vdots & \ddots & \vdots\\ a_{n1}  &   Q       &\ldots & Q \end{pmatrix} $$ where the $a_{ij}$ elements are real and predetermined, the $Q$'s are placeholders and not necessarily equal to one another, and $A$ is square of size $n$x$n$. I am looking to find values for all $Q$'s such that $A$ is unitary. To do this I have attempted to set up a system of nonlinear equations of the form $AA^\dagger=I$ which yields a system of $n^2-n$ unknown $Q$'s, but only $n^2/2 +n/2$ equations after removing any duplicate equations. Therefore, for $n=2$ the system is over-determined and for $n>3$ the system is under-determined. My question is, is there a method in which I can solve for $Q$'s to force $A$ to be unitary given these constraints for any size n?


How do ARMA and ARMA-GARCH models relate?

I would like to understand how GARCH models work but I'm having some problems. I have a highly persistent AR time series and I would like to model the conditional mean as well as its conditional variance. I thought of 2 possible ways:   Estimate an AR(1) model, obtain the residuals, fit a GARCH(1,1) to the residuals. The first model models the mean, the second model the variance. Estimate an ARMA-GARCH model.   I assumed, that both ways should yield the same results in terms of coefficients but that's not the case. Why do the AR coefficients differ?  I have created a reprex in R. You only need the fGarch and tseries packages besides base.    library(fGarch) library(tseries)  # Simulate time series with heteroscedasticity set.seed(1) y <- c(0) for(i in 2:5000) {   y[i] <- 0.99*y[i-1] + rnorm(1, sd = (sin(i/300)+1)^2)  } plot(y, type = "l")     # Model Estimation  # Estimate AR 1  model_arma <- arma(y, order = c(1,0,0)) model_arma$coef #>        ar1  intercept  #>  0.9820884 -0.0391143  resids <- residuals(model_arma)[-1]  # Estimate Garch(1,1) model_garch <- garchFit(~garch(1,1), trace = FALSE) model_garch@fit$matcoef #>            Estimate  Std. Error    t value     Pr(>|t|) #> mu     -0.006190316 0.008461996 -0.7315433 4.644474e-01 #> omega   0.010761385 0.002837514  3.7925399 1.491143e-04 #> alpha1  0.153134061 0.026421658  5.7957780 6.800519e-09 #> beta1   0.805973743 0.033381268 24.1444916 0.000000e+00  # Estimate Arma-Garch model_armagarch <- garchFit(~arma(1,0) + garch(1,1), trace = FALSE) model_armagarch@fit$matcoef #>            Estimate  Std. Error    t value     Pr(>|t|) #> mu     -0.006097132 0.008400905 -0.7257709 4.679792e-01 #> ar1     0.051377942 0.025641637  2.0036920 4.510307e-02 #> omega   0.011189102 0.002820163  3.9675370 7.261924e-05 #> alpha1  0.157402606 0.026259893  5.9940306 2.047028e-09 #> beta1   0.799952222 0.032890817 24.3214454 0.000000e+00   Created on 2019-12-20 by the  (v0.3.0)


PNGs made in GIMP not coming out transparent

I’ve had this happen with more than one image lately.   I open an image in GIMP with the purpose of making the background transparent. The first thing I do is Add Alpha Channel. I proceed to remove the background. Once I’m done with that, I export as PNG. But the background isn’t transparent. I can’t figure out for the life of me why that is. I’ve never had this problem before. The image is in RGB mode. I’m using GIMP 2.8.10. Is there some obvious step I’m missing?


Why do motorcycles front wheels lift of the ground when accelerating quickly

When motorcycles accelerate quickly they do a wheelie. Where is the torque provided to lift the motorcycle?


unable to draw polygon without attribute window popping up?

I'm fairly new to QGIS and an trying to draw a polygon via "Adding Feature". When I make the first left click to start, the attribute window pops up instead of letting me continue on with additional points.  don't seem to offer a solution?


I am looking for books on Aristotle's Categories with academic commentary, preferably with references to further development of logic.


I am working with Laravel but i have installed all on my own (php, mysql, composer, nginx) and now i need to install Redis and configure it so i could use it for queue driver in Laravel.  How to install it, because it cannot be installed through apt-get install redis  i get this error:  ubuntu@ubuntu:~$ sudo apt-get install redis [sudo] password for ubuntu:  Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package redis


How can i delete elements in a list with remove order?

I have a list like this  lst = [1,3,5]  and a major list like lost =['the' , 'cat' , 'thinks' , 'you' , 'are' , 'crazy' ]  I want to delete elements in second list based on indexes in the first one . It means i have to remove 'cat' , 'you' and 'crazy' . The problem is if i use : lost.remove(lost[1]) lost.remove(lost[3]) lost.remove(lost[5])  First problem is its not gonna work out! Because as we remove the first element the length of the list(named lost) decreases and in that way we will remove wrong elements. Second problem is the list named(lst) will not always be [1,3,5] . Its gonna change in length and in elements . How can i fix the problem?


A few years ago Umber Ferrule wrote that the toolbars in the taskbar are defined in   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Streams.   This looks very plausible but cannot be the entire story.  Deleting this key will in no way affect the taskbar and on rebooting the system the key magically reappears.  Why do I want to know?  Simple.  I would like to export the key to a reg. file as a convenient backup.


Author year citation style with manually created \bibitem entries

Is it possible to use natbib's citation commands (citep and citet) and an author-year citation call-out style while building each \bibitem manually inside the main tex file?  The template I using for a journal submission does not allow external reference files  Edit: Following the sugestion os @Mico I managed to make the citep work but citet are not right:  As explained in (author?) (Keele et al. 2007), these set of guidelines (...)


I've found several answers on switching between an Adapter and a Battery. But I need to autmoatically switch between two batteries. One of them is 'hotplugable'.  Problem: I've got a Solarcell which charges a ~16000mAh Li-Ion battery (BATa). Once in a while, the Solarcell doesn't manage to charge the battery enough. It's crucial that I have 3.0 to 4.1 Volts on my VSYS but the voltage will drop below this value if the Solarcell wasn't able to do its job (cloudy weather, vulcano eruption [joke], dirty cells, etc).  My Plan: I've come up with the idea to feed the VSYS with a additional, hotplugable backup battery (BATb) which does get connected to VSYS if BATa drops below ~3.1v.  So basically I need a Low-Voltage-Cutoff (using a Z-Diode with a Mosfet?) which, when cutoff happens, opens another Mosfet..?         – Schematic created using   I'm not sure about the selection of M2 and how to wire it, so it will be conductive if M1 won't forward power anymore.  And I know about another electrical problem: Just using a Z-Diode (D1) with M1 will render M1 to something like a resistor, not a switch. I've read, that I could use something like a Shut Reference (i.e. TI's TL43xx). Again I'm not sure how to chose the correct one and how to wire it.


Are galaxies, stars, planets, and ultimately life in violation of the second law of thermodynamics?

How can we think about entropy in these situations? To my knowledge all of these structures are born out of gravitational interaction. However, it would seem that the formation of these more organized structures conceptually violates the second law of thermodynamics. Is this dilemma arisen from my flawed understanding of thermodynamics or are these structures actually in a way defying an increase in entropy?


Why can't I login on the remote computer without a password after using SSH-KEYGEN command?

I have two computers. From the first I created the account admin1 with password admin1. Then I logged in as a root user and used the ssh-keygen -t rsa command. I did not give a password and hit Enter three times.    In the next step I typed ssh root@remoteuser's ip. Then I logged out and tried to connect to the second computerm but it asked for the password again...  Next, I used the commands:  #useradd admin1 #passwd admin1 #ssh-keygen -t rsa #ssh root@remoteuser's ip   Why does it ask for the password again?


How do you get Mac OS Finder to group folders together when sorting?

I have Mac OS 10.7.4 and I'd like Finder to use "Is Folder?" as its first sort criteria, or in other words, group folders before files regardless of the sorting method.  Windows and Linux both do this by default.


Localhost printer stuck at "Rendering Completed"

I am unable to print documents using my HP printer. However, I am able to print test pages.  What I tried:  I have tried removing and re-installing the printer from the system settings but I can only print once (the first task). Then all the following tasks get stuck at the "Rendering Completed" status.  I additionally tried restarting the computer which leads in the same task mentioned above.  Moreover, I logged into the CUPS system ( 1.6.2) from http://localhost:631  From there, I removed the printer, restarted it and re-installed with no sucess.  System Specifications:  System : Ubuntu GNOME 13.04  Memory: 3.9 GB  CPU : AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ × 2   OS-type : 32 bit  Graphics: Gallium 0.4 on NVA3  Printer: HP Deskjet 2050 j510 Series  IP Adress: localhost  I had no problems with my previous OS which was Pinguy OS 11.04 ( a distro based on Ubuntu 11.04) and it's the first time I use my printer at this OS.  Screenshots:   My printer stuck at "Rendering Completed" status.     From the CUPS web interface; you can see that "Rendering Completed" is stuck at the state of the print process.  **EDIT:**I tried printing from the pdf.js pdf viewer of firefox: I wait for about 5 minutes for a 10 pages document to print, the document is printed like faded and sort of in bold font (I accuse rendering for that). Then the status of the printer gets stuck at 'Rendering Completed' but I can print later on. Again, for the next prints I wait for 5 minutes minimum ( I wait for the 'Rendering....' bar to fill ) and the printing is weird.


$ (1 + x)^{1/x} $ when $ x \to \infty$ without L’Hospital’s Rule

Title is the question itself.  How can I show below without L’Hospital’s Rule  $$ \lim_{x\to \infty} ( 1 + x )^\frac{1}{x} = 1 $$


Does a function that satisfies the equality $f(a+b) = f(a)f(b)$ have to be exponential?

I understand the other way around, where if a function is exponential then it will satisfy the equality $f(a+b)=f(a)f(b)$. But is every function that satisfies that equality always exponential?


Why are changes in one branch(create from master) of visual studio(git) applied to master?

in visual studio, I create a new branch from my master branch, write something new, and these changes also appear there when switching to the master branch.Can someone tell me how to configure it so that they do not go there automatically?Thanks


Use Mittag-Leffler to prove Weierstrass Factorization Theorem

Use the Mittag-Leffler theorem to prove the following:  Let $(a_n)$ be a sequence in a simply connected domain $D \subset \mathbb{C}$ that does not have an accumulation point in $D$.  Prove that there exists a holomorphic function $f$ so that its zero set equals $(a_n)$ counting multiplicity.    In particular, do not use the Weierstrass Factorization Theorem, Weierstrass Products, or Blaschke Products in your answer.  I have no idea how to do this problem.  Can someone help?


Create a shortcut in TeXstudio for $*$ and automatically move cursor to *

Like prompt says, I want a command to allow quicker mathematical equations. I have created my own commands in the past but cant figure this out.  Ideally I would end up with a shortcut like \m or Alt+M that would type $$ and then press the left arrow key.    If this cannot be done native to TeXstudio, could someone suggest a good minimalist macro program to make this work?


If $f(x)=\begin {cases} x^a\sin (1/x) & x\not =0 \\ 0 & x =0 \end {cases}$ is continuous but not differentiable at $x=0$ find $a$

If $$f(x)=\begin {cases} x^a\sin (1/x) & x\not =0 \\ 0 & x=0 \end {cases}$$ is continuous but not differentiable at $x=0$ find $a$. Since the function is continuous $$\lim_{x\to 0} x^a \sin \left(\frac 1x\right) =0.$$ Function is not differentiable at $x=0$ $$\lim_{h\to 0} \frac {h^a \sin (\frac 1h)}{h}$$ $$=\lim_{h\to 0} h^{a-1} \sin \left(\frac 1h\right)$$ must not exist. How do I find the interval of $a$ from these two results?


Which characters in Tiny Death Star can be unlocked without paying in Imperial Bux?


Binomial coefficients identity : $\sum_{k=1}^{n-m+1} k\binom{n-k+1}{m}=\binom{n+2}{m+2}$

For any positive integer m&n.$n\ge m$ , let $\left( {\begin{array}{*{20}{c}} n\\ m \end{array}} \right) = {}^n{C_m}$. Prove that $\left( {\begin{array}{*{20}{c}} n\\ m \end{array}} \right) + 2\left( {\begin{array}{*{20}{c}} {n - 1}\\ m \end{array}} \right) + 3\left( {\begin{array}{*{20}{c}} {n - 2}\\ m \end{array}} \right) + .. + \left( {n - m + 1} \right)\left( {\begin{array}{*{20}{c}} m\\ m \end{array}} \right) = \left( {\begin{array}{*{20}{c}} {n + 2}\\ {m + 2} \end{array}} \right)$ My approach is as follow $n=4, m=2$ $\left( {\begin{array}{*{20}{c}} 4\\ 2 \end{array}} \right) + 2\left( {\begin{array}{*{20}{c}} 3\\ 2 \end{array}} \right) + 3\left( {\begin{array}{*{20}{c}} 2\\ 2 \end{array}} \right) = \left( {\begin{array}{*{20}{c}} 6\\ 4 \end{array}} \right) = 15$ $6 + 6 + 3 = 15 \Rightarrow LHS = RHS$ But not able to solve it via property


Do I need to perform my next hack within 24 hours of the current one in order to keep Sojourner alive?

In Ingress, if I hack a portal at 3pm, do I need to hack the next portal before 3pm the following day if I want to keep my current hacking streak (for the Sojourner badge) alive?


When is the new ball due for all forms of cricket?

Is there a standard time fixed in Test, ODI and T20 formats of Cricket, when a fielding side captain can ask for a new ball?  If the captain of the fielding side doesn't ask for a new ball, will he be forced to have it mandatorily after a certain point by the match umpires?


Add a property to a JavaScript object using a variable as the name?

I'm pulling items out of the DOM with jQuery and want to set a property on an object using the id of the DOM element.   Example  const obj = {}  jQuery(itemsFromDom).each(function() {   const element = jQuery(this)   const name = element.attr('id')   const value = element.attr('value')    // Here is the problem   obj.name = value })   If itemsFromDom includes an element with an id of "myId", I want obj to have a property named "myId". The above gives me name.  How do I name a property of an object using a variable using JavaScript?


Set variable conditionally on command line

I want to set a variable if my condition is true on my Ubuntu system.  This proves that my if-statement is correct:  $ (if [ 1 == 1 ]; then echo "hi there"; fi); hi there   This proves that I can set variables:  $ a=1 $ echo $a 1   This shows that setting a variable in the if-statement DOES NOT work:  $ (if [ 1 == 1 ]; then a=2; fi); $ echo $a 1   Any ideas why? All my  indicates that it should work like this...


I have been trying to grid a point cloud, version1.2, LiDAR datasets which are intended to be used for hydraulic simulation of flood propagation. Already, I have used Arc* to work on the traditional (.las) format, to create lasdataset. Then, a raster dataset was created from the lasdataset and finally interpolated by means of a nearest neighbour algorithm.  The interpolated raster data were exported as txt files.   Having gone through this routine, I expected a result with header file as well as regular values in X, Y and Z orthogonality. Instead, the result I got was distorted sets of (real) numbers I could not make sense of.  I tried using Surfer* to grid txt files created from (.las) point clouds, by means of lastools*, but the result was a binary file and I couldn’t read it. Lastools* gave a reasonable result when used to grid the point clouds, only that the cell size varies inversely with the number of cells that result in the output grid.   My challenge is how to grid the point cloud LiDAR and specify the number of rows and columns to be contained in the resulting gridded data, giving a fixed cell size.


How do I connect my domain to my local Ubuntu Server?

I already have purchased a domain and set up a local server now it's just linking them.  I also have it configured so it uses a local IP 10.0.0.174, will I need to do anything else to change this so the registrar can link to a public one and how? What are the steps I should take?   This is my first time hosting a website by myself. Also, any tips maybe?


Question: Prove $\forall n\geq 2,n\in\mathbb{Z}$, $(n+1)\mid(n^3+1)$    I know that it is possible to solve by factoring $n^3+1$ and showing that $n+1$ is a multiple, but I would like to show this via induction.  Attempt: Using induction:  Let $n=2:3\mid 9$, so true for $n=2$  (1) Assume true for $n=k:(k+1)\mid(k^3+1)$, so $(k+1)r=k^3+1$ for some $r\in\mathbb{Z}$  (2) Let $n=k+1:(k+2)\mid(k+1)^3+1$, so $(k+2)s=(k+1)^3+1$ for some $s\in\mathbb{Z}$  From (2) we have $(k+1)s+s=(k+1)^3+1$, subbing (1) into (2), I get $k^3+1+s=(k+1)^3+1$  Therefore $k^3+s=(k+1)^3$.  Setting $s=3k^2+3k+1$, this holds.  Where am I going wrong, is the proof valid, any help would be greatly appreciated.


I've done the Blood on the Ice and Morning Never Comes quests and I've helped citizens and stuff but I still can't buy Hjerim.  I have an Xbox 360 so I can't use console commands but my brother's profile that is on the same Xbox got the house! I really need the house, it's perfect for me. Why can't I buy it?


javascript Cannot pass variables between 2 functions

I am wondering how to pass a variable between 2 functions.   I have looked on Stackoverflow but all examples I tried did not work for me.  I have function, which calculates an array: arrR.  Now, I would like to call this variable somewhere else:  function my_function(arrR) {     return(arrR[1]); }  function onRefresh(chart) {     chart.config.data.datasets.forEach(function(dataset) {         dataset.data.push({             x: Date.now(),             y: myfunction(arrR)         });     }); }   But y: myfunction(arrR) gives notting. I have checked that if I put some number say y: 1 this works.  Any clue ?  Many thanks


What is the difference between a path and a stroke?

Is a path the set of points from a to b?  And is the stroke the "definition" (i.e. the color, shape, etc.) of the path?  And, how can you have a path with no stroke?  Is this only because it is a computer drawing program?  In the real world you can't have a path without a stroke can you?  If it matters, I am using Inkscape.


Why can't I create an equation in my list?

\documentclass[11pt]{article} \usepackage{physics} \usepackage{blindtext} \usepackage{amsmath} \usepackage{bm} \usepackage{cancel} \usepackage{sidecap} \usepackage{array} \usepackage[utf8]{inputenc} \usepackage{enumerate}  \title{} \author{Author:\\ \hfill\\ Registration Number: } \date{Date:}  \begin{document} \maketitle  \section{}  \subsection{}  \begin{enumerate}[i.]  \item my text \item my text \item my text  \noindent\rule{12.6cm}{0.7pt}  \item   \begin{equation}              \frac{y[n]}{x[n]} = \frac{1}{2}  \end{equation}  \item   \end{enumerate}  \end{document}   This is the outline of the document but I'm getting the error "missing $ inserted ... $". I've never had a problem with using the equations before so any help would be appreciated.


Context:  We are running a system which has our Linux & Unix Boxes authenticate against AD and because we have numerous different versions of Unix/Linux, we have to default to /bin/sh to make sure that the logins always work no matter the Server. I am looking to setup a .profile on RHEL to check to see what shell is set to at login and if its not bash, to switch to bash. I am not having any luck google searching for a method to do this and my shell scripting is on the weaker side.   Question:  How does one check for shell and switch at login without the control of the passwd file?


Apply sudo on whole command line (stdout redirection)

I'm trying the following :  sudo iptables-save > /etc/iptables/Firewall.rules   but I get permission denied: Firewall.rules even if ls -l tells me that root has writing permission for this file :  -rw-r--r-- 1 root root  362 Aug  3 14:26 Firewall.rules   Is it normal?  When I run su and then directly try this redirection as superuser (without sudo), I have no problem.  Even if I'm not sure, my guess is that sudo only applies on the iptables-save command and not on the > redirection (sudo(iptables-save) > file instead of sudo(iptables-save > file) if I had to express the priorities with parenthesis and pseudo code).  If I'm right about this, how could I apply sudo to my whole command line?  If I'm wrong, what did I miss?


Can a PF cleric create 9600 gallons of water a day?

It seems like cleric in PF can use unlimited times of 0-level spell a day.  By a simple calculation, a level 1 cleric working for 8 hours a day can create 9600 gallons of water a day, by using the  spell.  Am I misunderstanding the rules or is that how the Pathfinder rules work?  If a cleric can provide water for a whole town of people in a desert, this will surely bring a huge effect on desert civilizations. I am not very familiar with the worlds and settings of Pathfinder, did the designers consider these types of things when making the setting?


how to generate a random long with 4 digits in java?

how to generate a long that is in the range of [0000,9999] (inclusive) by using the random class in java? The long has to be 4 digits.


How to get the exit status of multiple parallel background processes in bash

In Bash, I want to call a command multiple times in parallel, while capturing all the processes exit codes.  I know how to start and wait for them, but wait will only give me the exit code of the last process exiting. I also need the exit code of the shorter lived processes.  Unfortunately I don't have bash 4.3, so wait -n is not an option, nor is gnu parallel as suggested in    pretty much asks the same question but no solution was offered there either.  The only way I can currently think of is writing a helper script that stores the exit codes in a file, but this doesn't sound like a clean solution.


Possible Duplicate:          I've got a custom HTTP server written in C# which gives me the raw HTTP request...   GET /ACTION=TEST HTTP/1.1 Host: localhost:8080 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.0.10) Gecko/2009042316 Firefox/3.0.10 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-gb,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive   Is there something in the .NET framework that I can use to parse it or do I have to do it by hand?   Cheers


The desktop site lists a question's view count on the top right corner of every question page, but I don't see a way to check views on the iOS app or mobile site.  Can an option be added to view a question's view count on the Stack Exchange iOS app?


Enlarge a partition without losing data with Windows 7 diskmgmt?

I have a 320GB hard drive currently partitioned as below:     A long time ago, a computer expert formatted my hard drive like this because I wanted to install Ubuntu. I'm now ready to do this, but I'll never need so much free space (103.09GB). I want to enlarge the D:\ volume because it already has lots of data on it.  I know that when I open diskmgmt.msc, I could possibly enlarge the D:\ volume using some free space from the unformatted 103.09GB volume, because the program offers me the option to enlarge. However I'm afraid that I might lose data doing this.  Is it possible to enlarge the partition with this Windows 7 tool or am I better using GParted via "Try Ubuntu" on my Live CD? Would either of them cause data loss in this scenario?


Are there nonisomorphic, finitely generated groups that surject onto each other?

Are there nonisomorphic, finitely generated groups that surject (homomorphically) onto each other? For example of the 'dual' problem, the free group on $2$ generators $F_2$, and the free group on $3$ generators $F_3$ inject into each other; but there is no surjection from $F_2 \to F_3$ (intuitively, if there was was, since $F_3$ surjects onto $\mathbb{Z}^3$, there would therefore be a surjection $F_2 \to \mathbb{Z}^3$, but the image of such a map could only be a $2$-dimensional sublattice of $\mathbb{Z}^3$, so we have a contradiction)


I have a LG Android.  How do I change language settings on the phone itself?  Sometime today, the language on the phone displays changed from English.  I'd like to return to English.  I suspect it'd be in settings, but where? Thank you.


How to check a specified regular expression in c#

I am a beginner in Regular expressions and  I want to check if a string variable satisfy a specified expression like this :   R|numeric_value|^value0^^^value1|value2|value_or_null|date_value   Note : The symbols (| and ^) are mandatory static characters and they are considered as Fields delimiters  any one help please!  Thanks in advance


The Stack Exchange API v2.2 is down / unstable

I opened the Android app and was met by the "Loading stack exchange sites" splash screen. The spinner froze, then a black screen appeared, then the entire app froze. I tried a few more times and was met with the same results.  The full site also works fine on my phone, so it appears to just be the app.   On the iPhone app, I keep getting a "Request timed out. Tap to retry." message when loading the question body. The title gets loaded, as is the HNQ list and my own notifications, but no posts. The mobile site is working.    Requests to the API never load:


Changing the default file path for \addplot table {myfile}

Is there a way to add a file path prefix (ideally defined by a key) to the "argument" of \addplot table. Something like  \documentclass{standalone} \usepackage{pgfplots} \pgfplotsset{%   table file path/.initial = {./}} \begin{document} \begin{tikzpicture}   \begin{axis}     \pgfplotsset{%       table file path = {./cvsfile/}}     % Plot ./cvsfile/myfile     \addplot table {myfile};   \end{axis} \end{tikzpicture} \end{document}


What is the difference? "had been" vs "was"

What is the difference between this sentences?     I had said no, because I was in the middle of getting Windows NT   shipped, and because Microsoft had been generous with stock options.      I had said no, because I was in the middle of getting Windows NT   shipped, and because Microsoft was generous with stock options.


How to construct such a function satisfying the following condition?

I came across such a problem. It asked me to construct a function $f$ on $\mathbb{R}$ with the property that, for all $p \in (1, \infty)$,  $$\int^{\infty}_{-\infty}|f(x)|^pdx<\infty \iff p=4.$$  I have no clue where to start. I've tried something like $\frac{1}{x^{1/4} lnx^{1/4}}$, but it doesn't seem right. Does this problem involving functional analysis? Can anyone enlighten me? Thanks in advance.


How to get string list of Enum descriptions?

How can I get a List of an Enum's values?  For example, I have the following:  public enum ContactSubjects {     [Description("General Question")]     General,     [Description("Availability/Reservation")]     Reservation,     [Description("Other Issue")]     Other }   What I need to be able to do is pass ContactSubject.General as an argument and it returns the List of the descriptions.  This method needs to work with any Enum, not just ContactSubject (in my example). The signature should be something like GetEnumDescriptions(Enum value).


Raw cream safe to consume after 125 F for 12 hours?

I was attempting to make clotted cream with pure raw cream (jersey cows) from the dairy farm.   I had my temperature too low I think though. I had it "cooking" at 125 F for 12 hours. It should have been 160 F for 12 hours.  Can I increase the temperature and cook for additional time?  Some websites say temperatures as low as 110 F will work for clotted cream.


Android : SMSManager - Attempt to get length of null array

I have a bug from the SMSManager when I try to send a message with the method sendTextMesasge. It returns me a java.lang.NullPointerException: Attempt to get length of null array.  There is my code :          // Constructs the message         TelephonyManager mTelephonyMgr = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);              String myPhoneNumber = mTelephonyMgr.getLine1Number();         String destNumber = taskManager.getHelpCenterNumber();         String message = getResources().getString(R.string.call_me_message) + " " + myPhoneNumber+".";          // Sends the message         SmsManager smsManager = SmsManager.getDefault();         smsManager.sendTextMessage(destNumber, null, message, null, null);   The LogCat receives this message :  08-03 09:59:10.548: E/AndroidRuntime(19825): FATAL EXCEPTION: main 08-03 09:59:10.548: E/AndroidRuntime(19825): Process: com.solarsquareretailer.view, PID: 19825 08-03 09:59:10.548: E/AndroidRuntime(19825): java.lang.NullPointerException: Attempt to get length of null array 08-03 09:59:10.548: E/AndroidRuntime(19825):    at android.os.Parcel.readException(Parcel.java:1546) 08-03 09:59:10.548: E/AndroidRuntime(19825):    at android.os.Parcel.readException(Parcel.java:1493) 08-03 09:59:10.548: E/AndroidRuntime(19825):    at com.android.internal.telephony.ISms$Stub$Proxy.sendText(ISms.java:1428) 08-03 09:59:10.548: E/AndroidRuntime(19825):    at android.telephony.SmsManager.sendTextMessage(SmsManager.java:305) 08-03 09:59:10.548: E/AndroidRuntime(19825):    at com.solarsquareretailer.view.MainActivity.onOptionsItemSelected(MainActivity.java:245)


Which characters played the parts of the lineup discussed by Rusty and Daniel?

In planning the heist, Rusty names a number of roles that are going to be needed to pull off the job.      Off the top of my head, I'd say you're looking at a Boesky, a Jim Brown, a Miss Daisy, two Jethros, and a Leon Spinks. Not to mention the biggest Ella Fitzgerald ever.   Which characters in the film lined up with these named roles?


My headphones are not playing voices, but only the music

I'm using stereo headphones on Windows 8. When I play songs I can't hear them normally.  Instead I'm only able to hear just "blurry" music, so I can barely hear the voices singing.  How can I resolve this problem?


Am I missing a trick to solving a 3D potential well problem?

I was playing around with a 3-D potential $V$ such that $V_{(r)} = 0$ for $r<a$, and $V_{(r)} = V_0>0$ otherwise. By using the Schrödinger Equation, I showed that: $$\frac{-\hbar}{2m}\frac{1}{r^2}\frac{d}{dr}\bigl(  r^2\frac{d}{dr}\bigr)\psi = E\psi$$  I then used the substitution $\psi_{(r)}=f_{(r)}/r$ and $k=\sqrt{2mE}/\hbar$ to get: $$\frac{1}{r}\frac{d^2f_{(r)}}{dr^2}=-\frac{k^2}{r}f_{(r)} \tag{I}$$  which describes the wavefunction $\psi_{(r)}=f_{(r)}/r$ inside the sphere. Hence, the differential equation has the domain $0\leq r<a$, and I cannot multiply both sides by $r$. This is unfortunate, because there is a similar equation for the outside of the sphere: $$\frac{1}{r}\frac{d^2f_{(r)}}{dr^2}=\frac{k'^2}{r}f_{(r)}$$ As this is outside the sphere, I can multiply both sides by $r$ to get a familiar differential equation that can be solved easily: $$\frac{d^2f_{(r)}}{dr^2}=k'^2f_{(r)}$$  If I do the same thing to $(I)$, I obtain the equation for simple harmonic motion, but substituting the solution back into $(I)$ as a sanity check gives a division by zero when evalutating for $r=0$. After that, I tried a number of substitutions to make $(I)$ have a more recognisable form - to no avail. Then I had the idea of multiplying my trial solution by some other function of $r$ so that upon substitution into $(I)$, the evaluation of $r=0$ doesn't give an infinity... but I don't know quite how to do that...  Long story short..... my question is: what trick do I need to get a meaningful solution to $(I)$?


WFS works only in IE browser. Any work around is available for this issue?

WFS works only in IE browser for me.   It's not working in any other browser. I don't have much expertise in  checking browser compatibility, could someone suggest me how to resolve this issue or if any workaround is available for this issue to make it works in Mozilla and Chrome also.


I have a properties file (server.properties) and it looks like this:  ipaddress=10.x.x.x serverName=someName  and a lot of other values.  Let's say it is located at C:\Server\server.properties  Is there a way to modify the values using a batch script.  What would I do if I want to change serverName from "someName" to "myName" ? I can't use line numbers because it can change anytime.  This is not a duplicate of   I am trying to figure out how to replace the value of a property. Not replacing one word with another.  Thanks.


Why bother with the search for Horcruxes?

The biggest plan in defeating Voldemort is to hunt down and destroy all his Horcruxes, and a significant part of the last two books is spent doing this. Dumbledore, the most powerful wizard able to stand up against Voldemort, risks and sacrifices his life for it.  This is justified by Voldemort being immortal until all the Horcruxes are destroyed, so there is assumed to be no point in trying to kill him before that. But this justification doesn't make sense, for many reasons:   if he is killed again (in an ambush, in a fight, or an assassination), even if he doesn't truly die, his body will be killed, and he will spend a lot of time in a weakened state. Last time it happened, his side collapsed completely as soon as he died, and he needed 14 years to come back (the first 10 years of that being in a complete state of helplessness). It would be much easier to hunt for the Horcruxes while Voldemort was a weakened disembodied spirit and his supporters hiding or in Azkaban, than doing the same while Voldemort is in power, in the control of the Ministry, and you have to be constantly on the run from his goons. what if not all Horcruxes are identified correctly? The identity of most of them were just educated guesses. If Voldemort was even just slightly smart, he would have created one out of a pebble and hidden it in a desert. Or made it out of something heavy and dropped it into a volcano to sink deep into the Earth's mantle. even if not all Horcruxes could be found and destroyed, there are many other ways of permanently stopping him. Stun him, grab the body, then Obliviate all his memories. Or, if you aren't too morally restrained, then Crucio him to complete insanity. Or transfigure him into a piece of rock and bury it deep underground. Or place him in Azkaban, where he cannot use magic. And do it as soon as possible, instead of waiting until his followers get more and more numerous and gather more and more political power.   Am I missing something which makes it logical to try to find and destroy all Horcruxes before any attempt is made to attack Voldemort directly?


Why my minecraft always crashed when i play?

It's like this:  ---- Minecraft Crash Report ---- // My bad.  Time: 7/22/17 1:49 PM Description: Initializing game  org.lwjgl.LWJGLException: Pixel format not accelerated     at org.lwjgl.opengl.WindowsPeerInfo.nChoosePixelFormat(Native Method)     at org.lwjgl.opengl.WindowsPeerInfo.choosePixelFormat(WindowsPeerInfo.java:52)     at org.lwjgl.opengl.WindowsDisplay.createWindow(WindowsDisplay.java:247)     at org.lwjgl.opengl.Display.createWindow(Display.java:306)     at org.lwjgl.opengl.Display.create(Display.java:848)     at org.lwjgl.opengl.Display.create(Display.java:757)     at org.lwjgl.opengl.Display.create(Display.java:739)     at bhz.at(SourceFile:635)     at bhz.aq(SourceFile:458)     at bhz.a(SourceFile:404)     at net.minecraft.client.main.Main.main(SourceFile:123)   A detailed walkthrough of the error, its code path and all known details is as follows: ---------------------------------------------------------------------------------------  -- Head -- Thread: Client thread Stacktrace:     at org.lwjgl.opengl.WindowsPeerInfo.nChoosePixelFormat(Native Method)     at org.lwjgl.opengl.WindowsPeerInfo.choosePixelFormat(WindowsPeerInfo.java:52)     at org.lwjgl.opengl.WindowsDisplay.createWindow(WindowsDisplay.java:247)     at org.lwjgl.opengl.Display.createWindow(Display.java:306)     at org.lwjgl.opengl.Display.create(Display.java:848)     at org.lwjgl.opengl.Display.create(Display.java:757)     at org.lwjgl.opengl.Display.create(Display.java:739)     at bhz.at(SourceFile:635)     at bhz.aq(SourceFile:458)  -- Initialization -- Details: Stacktrace:     at bhz.a(SourceFile:404)     at net.minecraft.client.main.Main.main(SourceFile:123)  -- System Details -- Details:     Minecraft Version: 1.12     Operating System: Windows 10 (x86) version 10.0     Java Version: 1.8.0_141, Oracle Corporation     Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation     Memory: 48543712 bytes (46 MB) / 151007232 bytes (144 MB) up to 523501568 bytes (499 MB)     JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M     IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0     Launched Version: 1.12     LWJGL: 2.9.4     OpenGL: ~~ERROR~~ RuntimeException: No OpenGL context found in the current thread.     GL Caps:      Using VBOs: Yes     Is Modded: Probably not. Jar signature remains and client brand is untouched.     Type: Client (map_client.txt)     Resource Packs:      Current Language: ~~ERROR~~ NullPointerException: null     Profiler Position: N/A (disabled)     CPU: <unknown>


Prove that $|x_{n+1} - x_n| \le \theta |x_n - x_{n-1}|$ for some $0 < \theta < 1$

Let $x_1 > 0$ and $a > x_1 + x_1^2$. Recursively define $x_{n+1} = \frac a {1 + x_n}$ I want to prove that $x_n \xrightarrow{n \rightarrow \infty} \varepsilon \;$ where $\varepsilon + \varepsilon^2 = a \;$ ($\varepsilon$ is a root of $x + x^2 = a$) For this, I need to prove that $(x_{n+1} - x_n)(x_n - x_{n-1}) < 0 \;$ (which I've already done) and then I need to prove what's stated in the title: $\; |x_{n+1} - x_n| \le \theta |x_n - x_{n-1}|\;$ for some $0 < \theta < 1$ I'm getting stuck here. I tried proving it by IVT : Let $f(x) = \frac a {1+x}$. Then $$\begin{split} f(x_n) &- f(x_{n-1}) &= f'(c)(x_n -x_{n-1}) \\ x_{n+1} &- x_n &= f'(c)(x_n -x_{n-1}) \end{split} $$ Since $f'(x) = - \frac a {(1+x)^2}$ I have $|f'(c)| \le \max\left\{ \frac a {(1+x_n)^2}, \frac a {(1+x_{n-1})^2} \right\}$ So it would suffice to show $\frac a {(1+x_n)^2} < 1 \; \forall n \in \mathbb N$ I have tried but can't. It would suffice to show that the inequality is true for $x_1$ and that $x_n \ge x_1$ but it also escapes me