I know that polynomial (in a single variable) over any field has at most $n$ roots where $n$ is degree of the polynomial and in $\mathbb C$ it has exactly $n$ roots.  Now if coefficients are in any ring not a field, then any $n$ degree can have more than $n$ roots may have more roots, example $x^2=I_2$ in $M_2(\mathbb R)$ has $4$ roots  \begin{bmatrix}1&0\\0&1\end{bmatrix} \begin{bmatrix}-1&0\\0&1\end{bmatrix}\begin{bmatrix}-1&0\\0&-1\end{bmatrix} \begin{bmatrix}1&0\\0&-1\end{bmatrix}     Now my question is whether there exists a ring in which a finite degree polynomial has infinitely many roots.

Can a non-zero polynomial in one variable have infinitely many roots ? Can a non-zero polynomial in one variable have uncountably many roots ?  Motivation: over $\mathbb Z/12\mathbb Z$, $X^2-4$ has 4 roots. When it comes to polynomials with coefficients over an integral domain, the answer is clearly negative (in that case, a polynomial can't have more roots than its degree). What happens with a ring that has zero divisors ?


At which point of hook execution is the currently activated theme's functions.php file loaded?

So like WP must load series of files from,   index.php -> ... -> wp-header.php -> ... ->functions.php   ...and so on upon execution.   Also there must be a similar flowchart for functions callings, conditionals and such during the execution. Is such a flowchart(s) available anywhere?


I am using Ubuntu 18.04/18.10. How do I turn the snap to full screen feature OFF? This is a most annoying feature of OS these days. I run 2 screens and it is most annoying when moving to the other screen. I have turned off this function in Windows, but cannot find any function or selector to do likewise in 18.04/18.10.  Thank you in advance

When I move a window close to the top, it snaps to maximum size. I am using Ubuntu 18.04, GNOME 3.28.2.    How do I disable that? I searched about six months ago, no way to disable back then.  1/5/19 Yes, solved!  Thank you!   These two worked on my Ubuntu 18.04     gsettings set org.gnome.mutter edge-tiling false   dconf-editor   These did not work     GNOME Tweaks  (disable "Edge Tiling" not available)   gsettings set org.gnome.shell.overrides edge-tiling false    Thank you Kulfy, Hamza Saeed, vanadium, PRATAP.


When I am in views UI and I edit an option a modal box appears. I edit some seetings then press save and am displayed with something like:     [{"command":"settings","settings":{"basePath":"/","pathPrefix":"","ajaxPageState":{"theme":"bartik","theme_token":"SUIsCUisas2D3yeSiBkGNwaXtTMtlVVXouHWgoffCYA"}},"merge":true},{"command":"viewsDismissForm"},{"command":"viewsShowButtons"},{"command":"viewsTriggerPreview"},{"command":"insert","method":"html","selector":"#views-tab-block","data":"\u003Cdiv   id=\u0022edit-display-settings-details\u0022\u003E\u003Cdiv   id=\u0022edit-display-settings-top\u0022   class=\u0022views-ui-display-tab-actions views-ui-display-tab-bucket   clearfix\u0022\u003E\u003Cdiv class=\u0022ctools-no-js ctools-button   ctools-dropbutton\u0022\u003E\u003Cdiv   class=\u0022ctools-link\u0022\u003E\u003Ca href=\u0022#\u0022   class=\u0022ctools-twisty   ctools-text\u0022\u003Eopen\u003C/a\u003E\u003C/div\u003E\u003Cdiv   class=\u0022ctools-content\u0022\u003E\u003Cul class=\u0022horizontal   right actions\u0022\u003E\u003Cli class=\u0022duplicate ...   What could be going wrong?

I'm using Drupal v7.22 and whenever I try to Modify the Display on views, and press the 'Add and configure' button on adding a field, or any button that sends data to the server, the page reloads and I just get a long JSON String returned in Chrome, or IE will try to download the return...  Sometimes it'll accept my change, but more often than not, it won't.  It was doing this on 7.21 and then I updated to 7.22 and it stopped for a day or two, now it's doing it again.  I am extremely new to Drupal, but I am a quick learner and most things are going smoothly.  What did I break and how can I fix it?


When I type the command: sudo apt-get update, I got the error below: Err:12 http://ppa.launchpad.net/freyja-dev/unity-tweak-tool-daily/ubuntu focal Release   404  Not Found [IP: 91.189.95.85 80]  E: The repository 'http://ppa.launchpad.net/freyja-dev/unity-tweak-tool-daily/ubuntu focal Release' does not have a Release file.  Here is a full output of my command:  I would like to ask how to solve it. I am a novice and ask for help.

When updating, I get the following error message:   W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file.   Here, I find another statement on this error:   This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need.    Is this what I should do?


Something that is infinitely dense does not need to grow in size since they can pack an infinite amount of matter in a single point. So the fact that black holes grow in size means they are not infinitely dense right?

How do scientists calculate that density? What data do they have to calculate that?


I have created this bash function to recursively find a file.  ff() {     find . -type f -name '$1' }   However, it returns no results.  When I execute the command directly on the commandline, I do get results.  I am not sure why it behaves differently, as shown below.  mattr@kiva-mattr:~/src/protocol$ ff *.so mattr@kiva-mattr:~/src/protocol$ find . -type f -name '*.so'  ./identity_wallet_service/resources/libindystrgpostgres.so   Why does my function not work as expected?  I am using MacOS and bash shell.  Thnx Matt

Sometimes I see shell scripts use all of these different ways of quoting some text: "...", '...', $'...', and $"...". Why are there so many different kinds of quote being used? Do they behave differently or affect what I can do inside them?


I have the following SQL script: CREATE temporary table if not EXISTS the_values (  key SERIAL,  value INTEGER NULL  );  insert into the_values(value) values (null),(1),(null),(2),(3),(4),(5),(6),(10),(null),(null);  select *  from the_values  where value not in (1,2,3,4,5,6,10);   And I noticed that the query: select *  from the_values  where value not in (1,2,3,4,5,6,10);   Does not return the rows having value NULL, and that caught my attention. Therefore, I want to know why that happens. I am interested more about the technical aspect of this phenomenon rather that the obvious solution: select *  from the_values  where value not in (1,2,3,4,5,6,10)     or value IS NULL;

I had a query (for Postgres and Informix) with a NOT IN clause containing a subquery that in some cases returned NULL values, causing that clause (and the entire query) to fail to return anything.   What's the best way to understand this? I thought of NULL as something without a value, and therefore wasn't expecting the query to fail, but obviously that's not the correct way to think of NULL.


My customer's schematic uses a 0 ohm resistor for connecting analog(AGND) and digital (DGND). I think it is for testing, current measurement , fuse, jumper, test point etc but is there another reason?

This is related to another question I've just posted (), regarding the battery charger described in the , which one day I hope to build.  On page 40, there's a schematic showing the MCU connections (picture below). Marked in red is a 0Ω resistor that is puzzling me. I suspect that it is just a wire jumper linking AGND and GND. But I don't understand why there's a jumper there.     My questions:    What does the jumper represent? Why are AGND and GND separated like that?


Recently got a new pc, put the HDD from old pc into new one, reinstalled Steam however I want to use the library from old pc on new one but keep it on external.   New pc has a SSD which I do not want to fill up so going to put everything going to the external.  Any ideas please?

I uninstalled and re-installed steam. I didn't uninstall my games, and they still exist on my hard drive (I checked).  I have an SSD and a HDD, and to save space I install programs (including steam) to C:\Program Files (x86)\Steam drive (SSD) and games to D:\Games\SteamApps (HDD). How to I let steam know the programs are installed there?


I have created a content type called "Design" in which there are 3 fields. When creating this content type I want to hide the label of fields. How would I do that?

Is there a way to hide the field label when rendering a custom field in Drupal 7?  In my node template I have:  <?php print render($content['field_image']); ?>   Which gives me:

Image:&nbsp;

   I'd like to not have the
Image:&nbsp;
.  Is there a way to get rid of this other than in the CSS or manually creating the markup?   I've tried unset($content['field_image']['#title']), but that gives me
:&nbsp;
.


They supposedly have a 40,000 km (about a 25,000 mile) range, but over the years people have been transported to far greater distances. In the reboot Star Trek (2009) as example, Scotty and Kirk are shown to beam aboard Enterprise while it's traveling at warp, light years away. How can this be?

By "range of operation" of the transporter, I mean "distance up to which it could transport" or "distance from which it could transport something to its own location". The range of operation would have increased with time without a doubt but I want to know the average range at any period. It'll be better if you provide full stats of all times.


I was reading on wikipedia about  In the Precise definition part it says it can form close loops  but Kelvin–Stokes theorem it's written it  cannot be closed loops. (My teacher too told me that they never form close loops) Please point out Where I'm being wrong? I am asking about when can they form close loops? That question states Why can't electrostatic field lines form closed loops?

My physics textbook says "Electrostatic field lines do not form closed loops. This is a consequence of the conservative nature of electric field." But I can't quite understand this. Can anyone elaborate?


I would like to know if it is possible to update my Samsung Galaxy S3, which is in 4.3 Jelly Bean, to 5.0-lollipop. And in this case, I would like to know :   If it is a good idea ; Will my phone support it ;  What benefits it might bring me if it is possible.   I also would like to know the best way to proceed, to update my phone.  Thank you in advance.    Edit : I have a friend that has the same phone, and his phone updated itself. Why not mine?

This Community Wiki question is designed to be the "canonical question" for questions asking how to upgrade one's device to a new Android version.   I want to get a newer version of the OS for my Android device. How can I do that?  See also:


Some edges look sharp, but I haven't made them sharp. Auto Smooth - 57.3° (the same issue with any value) After applying the baked normal maps from Substance painter in blender, the model looks like this:  In Substance painter:  Material nodes:  Wireframe and sharpen edges in blue:

I'm having a small issue with visible seams on normal maps. The map was painted on Substance Painter and has no weirdness around seams. When I plug it into a Normal Map node set to Tangent Space this happens:   (it's a horse underside)  When I set the map to Blender Object Space the seams become nearly invisible, as they should be, but the shadows also looks awful.    What can be done to minimize the issue? I need to be able to use maps on tangent space. Moving the seams or hiding them under other stuff isn't always feasible.


Navigating the  page, with my browser maximized at my 1280x1024 px screen (this is not critical - the point is the full contents just fit the viewport, no horizontal scroll bar visible), when one clicks on the rounded rectangles (collapsed wrappers) on the right border, they expand towards the right, which is not very satisfactory.   See screenshots, before and after clicking over "User experience" site.      I'm not sure if this qualifies as a design bug, but anyway.

Since I am a regular Stack Overflow follower, I came across this and was shocked a bit regarding the design and user experience perspective.  Attaching picture 1 - it states that I can click any site and view a synopsis about it. Clear!!!    Attaching Picture 2 - you can see that when I clicked Webmasters, the design wants me to scroll horizontally to view all information and basically it hides information.    It would be nice, if it did something like below :


I am just starting into calculus and I have a question about the following statement I encountered while learning about definite integrals:  $$\sum_{k=1}^n k^2 = \frac{n(n+1)(2n+1)}{6}$$  I really have no idea why this statement is true. Can someone please explain why this is true and if possible show how to arrive at one given the other?


are formatted beginning with bitcoin: followed by a bitcoin address and optionally more information.   On my Mac, the Bitcoin-QT program is the default one to open when I click such links. I wish to change it to the Electrum client.   My question is - where in MacOS are the uri handlers defined? How can I change this to open my program of choice?

Some applications will signal to the OS that they can open special link type, such as ssh:// or github-mac://.  They get automatically opened for such links by the web browser (or when using open in a terminal).  If I have multiple such applications, how can I set which one should be the default?  For example, both GitHub Desktop and SourceTree can handle github-mac://. When I installed GitHub Desktop, it became the default handler for these links.  How can I set SourceTree as the default handler without uninstalling GitHub Desktop?


So my Eclipse works fine, it compiles everything I need. Now I just wrote code but it's not running it, it just doesn't do anything. I've tested Eclipse with other code and it works fine, so there is something wrong with my code, but I'm not sure what.  I am trying to complete Project Euler's 4th challenge:   A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99.  Find the largest palindrome made from the product of two 3-digit numbers.  Here's my code:  package me.practice;  public class Main{    public static void main(String[] args) {     int palindrome = 0;      for(int i = 0; i < 900; i++)     {         int num = (100 + i) * 999;          String numString = Integer.toString(num);          String numString_reverse = new StringBuilder(numString).reverse().toString();          if(numString == numString_reverse)         {             palindrome = Integer.parseInt(numString);              System.out.println(palindrome);              break;         }     } } }   Edit: I've also tried to run it on Netbeans and it doesn't work, so Eclipse is fine.

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


I've been working on creating an alarm app to run a music track that the user selects. So, after the user selects the track, it is converted from Uri to String by ".toString" method to be able to receive this Uri from a broadcast receiver so that it can be used in MediaPlayer.create(); after converting it back to Uri  Uri.parse(String track);   The problem comes when i try to play this it doesn't work although when I tested this in another activity it worked fine and I checked the uri.getPath() it tells me the path of the track so the problem is not because Uri object is empty.  public class AlarmTrigger extends Activity {     String trackPath;     Uri trackUri;     MediaPlayer mediaPlayer;      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_alarm_trigger);          trackPath = getIntent().getExtras().getString("Track path");          //getIntent from BroadcastReceiver class         trackUri = Uri.parse(trackPath);         Toast.makeText(this, trackUri.getPath(),Toast.LENGTH_SHORT).show(); // it works fine         AlarmGoes();     }      public void AlarmGoes(){         MediaPlayer mediaPlayer = MediaPlayer.create(this,trackUri);          mediaPlayer.start();     } }   The stack-trace:      java.lang.RuntimeException: Unable to start activity ComponentInfo{com.amr.mineapps.myapplication/com.amr.mineapps.awarm.AlarmTrigger}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.net.Uri.getScheme()' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2747) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2808) at android.app.ActivityThread.-wrap12(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1541) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:165) at android.app.ActivityThread.main(ActivityThread.java:6375) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:912) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:802)  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.net.Uri.getScheme()' on a null object reference at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1004) at android.media.MediaPlayer.setDataSource(MediaPlayer.java:983) at android.media.MediaPlayer.create(MediaPlayer.java:890) at android.media.MediaPlayer.create(MediaPlayer.java:867) at android.media.MediaPlayer.create(MediaPlayer.java:846) at com.amr.mineapps.awarm.AlarmTrigger.onCreate(AlarmTrigger.java:40) at android.app.Activity.performCreate(Activity.java:6845) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2700) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2808)  at android.app.ActivityThread.-wrap12(ActivityThread.java)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1541)  at android.os.Handler.dispatchMessage(Handler.java:102)  at android.os.Looper.loop(Looper.java:165)  at android.app.ActivityThread.main(ActivityThread.java:6375)  at java.lang.reflect.Method.invoke(Native Method)

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


I've one checkbox field Completed. which is update by using apex class.  I've created one checkbox field as Record Locked  when this field is checked true then; user unable to edit the record. i've to update Record Locked field automatically  when i write validation and check for the Record Locked is true; The problem is when i try to check Record Locked to true then validation also fire.  How can we do. Please Suggest

I have situation here, where I want to lock all the fields and buttons on a quote__c (custom object) where the status of the quote is changed to 'Sent' so that nothing can be editable on the quote.  Any ideas how to do this?


I found a little Winter Bash hat presentation bug (code name: TrumpHairLift). Of a run of a code snippet, the hat of the answering user doubles and lifts off. See this little animated GIF image I made from a screencast:  It was on  by Jamiec for the OP .

It seems like there is a bug that is causing a duplicate hat to appear when I expand info, like pressing "(more)" on a suggested edit. This bug does not seem to be specific to the suggested edits review queue though, as others have reported seeing this bug in other places, like code snippet expansion. Steps to repro:  Put on a hat. Navigate to one of your own suggested edits. (You can just also open the Suggested Edits review queue and go to a random suggestion, but there is no guarantee any of those users will be wearing a hat.) Click the "(more)" button to expand the top box.  What should happen: Hat should shift down with the rest of the content. What happens: All the content shifts down, but a duplicate hat remains in the initial place. Before expansion:  After expansion with duplicate hat:


I'm confused with the concept of tension in strings/rope. I have read that tension is an electrostatic force and is created due to the attractive forces by the particles. I can easily make out that when two equal forces are acting at the two ends of an ideal rope the tension is equal to that applied force, but, what happens when two unequal forces say F1 and F2 are acting at the two ends of the wire, why does the tension produced in the wire lies between the values of F1 and F2? More specifically if we consider any arbitrary particle on the string won't there be unequal forces at the two ends of the particle(i.e. F1 and F2). According to me, the tension should be the result of the two unequal forces. Seeking an answer which involves an explanation of the phenomena in the atomic scale.

Consider a massless rope with pulling forces applied at each end.  How do we decide if tension is constant or not in a rope? Consider a few example scenarios:  For example, if there is a knot in the rope the tension is not constant throughout (why?. Similarly, if the rope is hung over a cylindrical pulley of a non-negligible radius, the tension is not constant (why?). If there isn't anything touching the rope, for example, 2 people tugging on the rope at each end, the tension is constant (why?).


I want to change the opening page when I connecting using ssh this is what I have now :     Welcome to Ubuntu 15.10 (GNU/Linux 4.2.0-42-generic x86_64)         Documentation:           Last login: Tue Nov 29 13:43:00 2016 from 10.0.0.123   where do I change it  someone wrote to change /etc/motd but I don't this file  so waht do I need to change?  Thanks ,

So the default Ubuntu SSH banner has some cool stuff, mainly that it shows the packages that can be updated and whatnot. So I want to preserve those values, while customizing the rest of it.  I've already seen that I can point sshd_config to the file that would contain the text. I'm just unclear what commands will produce the update text.   For the record, what I'm talking about is this:  0 packages can be updated. 0 updates are security updates.   Help would be appreciated. Thanks so much.


I am trying to change the value of player_score, cpu_score, and ties which were created outside the function determineWinner but I get an error such as this: UnboundLocalError: local variable 'cpu_score' referenced before assignment.  I have deleted the other assignments (player_score=player_score+1 and ties=ties+1) and added the print ("Player Score",player_score) to test the program.  I don't understand is why  print ("Player Score",player_score) outputs the value assigned outside of the function but cpu_score=cpu_score+1 yields the "referenced before assignment" error.  Also showRolls does what it is supposed to.  It seems that the functions can read the values of the variables assigned outside of the functions but can not change the values.  Why is that?  import random  def showRolls():     print("Player 1 roll:",player_roll)     print("CPU roll:",cpu_roll)  def determineWinner():     if player_roll > cpu_roll:         print("Player wins!")         print ("Player Score",player_score)     elif cpu_roll > player_roll:         print("CPU wins!")         cpu_score=cpu_score+1     else:         print("It's a tie.")  #-----------------------MAIN PROGRAM------------------------------------ player_score=0 cpu_score=0 ties=0 player_roll = random.randint(1,6) cpu_roll = random.randint(1,6) showRolls() determineWinner()

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


I am in the process of writing some unit tests. In particular I want to test some private methods.  So far the I have come up with using.  #define private public   But I am not happy with this as it will destroy all encapsulation from the point of view of the unit test.  What methods do you use to unit-test private methods.

How do I unit test (using xUnit) a class that has internal private methods, fields or nested classes? Or a function that is made private by having  (static in C/C++) or is in a private () namespace?  It seems bad to change the access modifier for a method or function just to be able to run a test.


I lost my Android phone Vivo 1713 (v5s) recently. I don't know its IMEI number. How do I get it?

I had a Nexus S but lost it or it was stolen. I need to find it's IMEI. I don't have the box or documentation either.  I've checked exif data from photos taken with the phone.  What other potential sources are there for it's IMEI?


I want to show the number of nodes and comments of the author in the author's comment.  I try to put in template :   function MYTHEME_get_user_comments_count($uid) {     $query = db_select('comment', 'c');     $query->condition('uid',$uid,'=');     $query->addExpression('COUNT(cid)', 'comments_count');     $result = $query->execute();     if ($record = $result->fetchAssoc()) return $record['comments_count'];    return 0;  }   And in comment.tpl :   <?php print MYTHEME_get_user_comments_count(['comments_count'], $comment->uid); ?>   But it doesn't work.  Where have I forgery? Is this the right way?

I want to show the information of the author in his comment. By default it shows the name and the picture, I want to add:    The number of node and created comments The number of obtained .    What code should I use to achieve this?


Background  In Control Panel > Programs > Programs and Features > Installed Updates one can view all updates, sorting them by date installed. However, these updates are grouped by program before being sorted; meaning there's no simple way to find all updates installed in the last day; rather you have to look at the top few items of each program and make a note of these details.  My reason for doing this is sometimes an update to one component may affect another (e.g. .net framework, windows security, or adobe acrobat update could affect various parts of internet explorer's functionality; seeing all updates may give useful clues).  Question  Is there any way to remove the grouping by program from the Windows Installed Updates table?  Research So Far  I've searched Google, Technet and here, but no luck so far.  I've also tried removing the program column in the hope this removed the grouping - again no luck.

Windows 8.1 "installed updates" is one of two confusingly similar screens that let you view installed updates. It is the only non-useless one, because you can actually uninstall from this one. However it seems that there is some mandatory category groups that can not be removed, like "Microsoft Windows" and "Microsoft Visual Studio 2010", and so on. Hundreds of these categories.  Clicking on the "installed on" column only sorts items within their existing groups, making the sort feature useless for finding what was installed on what day, as you now have to consult each of 200 "group" sections and you can only sort INSIDE the groups. How do I turn off this "grouping" feature within Installed Updates, or otherwise see the most recently installed updates, by date, across all the categories or groups?  There is an Organize button, which is tantalizing, but the Organize button contains no way to hide the category names.    How can I see the most recent day (today, yesterday, 3 days ago) that any update was installed regardless of categories that they are sorted permanently into?  Known Workaround: Use the otherwise worthless "View update history" window instead.  (Review your windows update history). Then obtain a piece of paper and a pen, and write down the meaningless 10 digit KB number, then go find the meaningless 10 digit number in the other screen, and remove it.


I was using $ characters to mean, well, "dollars" in a question on Economics SE and it caused the rendered text to go all screwy.  I briefly reviewed the help text but could not zero in on the meaning of that character as markdown.  Finally just "escaped" the character with backslash and got on with things.  But what does $ mean in Markdown?  Does it have a special function on all SE sites, or only some?  (I've been on Stack Overflow and EL&U for a long time and never run across this problem.)

I want to write something basic like "10 $US" but sometimes it makes the text look weird. It changes the font and writes italic text. And sometimes it will insert a newline. For example in my .  How can I safely insert a dollar sign?


Show that the matrices  $$\left[\begin{matrix}1&0&0\\ 0&1&0\\ 0&0&1\end{matrix}\right], \left[\begin{matrix}1&0&0\\ 0&0&1\\ 0&1&0\end{matrix}\right], \left[\begin{matrix}0&1&0\\ 1&0&0\\ 0&0&1\end{matrix}\right], \left[\begin{matrix}0&0&1\\ 1&0&0\\ 0&1&0\end{matrix}\right], \left[\begin{matrix}0&0&1\\ 0&1&0\\ 1&0&0\end{matrix}\right], \left[\begin{matrix}0&1&0\\ 0&0&1\\ 1&0&0\end{matrix}\right]$$  form a group. Find an isomorphic of G with a more familiar group of order 6.  How do i prove that matrices are groups? would i find the det? or let a matrice be called A and assume things and try and prove it?

I'm asked to show that $G=GL_2(\Bbb Z/2\Bbb Z)$ is isomorphic to $S_3$. I have few ideas but I don't manage to put them all together in order to obtain a satisying answer. I first tried using Cayley's theorem ($G$ is isomorphic to a subgroup of $S_6$), and I also noticed that $\operatorname{Card}(G)=\operatorname{Card}(S3)=6$ & that they're both non-abelian group.  Is this enough to say that considering $S_3$ is a subgroup of $S_6$ with the same cardinality than $G$, it has to be isomorphic to it ?  Could anyone give me some elements to get a more rigorous proof or lead me to an other path to show this statement ?  Thanks in advance


Inside a multi-gang box I have a hard time working with the 12-gauge wire. Is it ok to connect them with a wire nut to a 14-gauge and then connect to the switches. The box has switches to light, heater, humidifier. The circuit breaker is 20 amps. The current wiring is 12 gauge everywhere it seems. This is in a small bathroom in TX.

I’ve used 12 gauge wire and 20 amp breakers in my basement.  They go into a shallow box and the 12 gauge is difficult to work with.  Can I drop to 14 gauge in the receptacle boxes and pigtail the connection ?


I have a variable data that contains some key-value pairs like this:  var data = {     "1": 127,     "2": 236,     "3": 348 }  router.delete('/values/:id', function(req, res, next){     var id = req.params.id;  })   How can I delete the key-value pair that has a key equal to the id variable?

Say I create an object as follows: let myObject = {   "ircEvent": "PRIVMSG",   "method": "newURI",   "regex": "^http://.*" };  How should I remove the property regex to end up with new myObject as follows? let myObject = {   "ircEvent": "PRIVMSG",   "method": "newURI" };


The First Hokage sealed the shadow clone jutsu . If this is true, how was Kiba able to learn it?

While the Kage Bunshin no Jutsu seems to be taught, the Tajuu Kage Bunshin no Jutsu is sealed, so nobody can learn the jutsu. Does that mean that there's a difference between these jutsus, aside from the number of Kage Bunshin created?   Or, why was the Tajuu Kage Bunshin no Jutsu sealed away? If there's no other difference, everybody could use this without reading the sealed scroll.


Suppose that R is a ring with unity, $a, b \in R$ and that neither a nor b      is a zero divisor. If ab unit, then a and b are units.   I know that a ring with unity means that   $$\exists 1_{R} \in R:\forall a \in R: 1_{R}a = a = a1_{R}.$$  For an element $a \in R$ to be a zero divisor we must have $a \neq 0_{R}$ and there must exist an element $\hat{a} \neq 0_{R}$ such that $a \hat{a} = 0_{R}$ or $\hat{a}a = 0_{R}$. Therefore, the meaning of not a zero divisor would be that given $a \neq 0_{R}$ we must have for every $\hat{a} \neq 0_{R}$ that $a\hat{a} \neq 0_{R}$ and $\hat{a}a \neq 0_{R}$. Similarly, for b we then have $b\hat{b} \neq 0_{R}$ and $\hat{b}b \neq 0_{R}$.  For $ab$ to be a unit there exists $(ab)^{-1} \in R$ such that $(ab)^{-1}ab = 1_{R} = ab(ab)^{-1}$.  Now, I have to show that $\exists a^{-1}, b^{-1} \in R$ such that $a^{-1}a = 1_{R} = aa^{-1}$ and $b^{-1}b = 1_{R} = bb^{-1}$.  I have no starting point thus far so any hint(s) are greatly appreciated.

Suppose $R$ is a ring with no zero divisors and with identity $1_R$ not equal to $0_R$.  Suppose that $a,b$ are in $R$ and that $ab$ is a unit.  Prove that $b$ is a unit.   My thoughts: I know a unit is basically a unit that (for this example) would mean $abu = 1_R$ for some nonzero $u$ in $R$.  I am really stuck after that.  Not seeing a clear path to manipulate the variables to prove b is a unit by itself.


I am new on coding just need find out if it is possible to get methods name and print using console.write. Here I have sample class and I want to grab "myName" so I can use it to print.  using System;  namespace Tests {     class Class1     {         public void myName()         {             Console.Write(myName);         }     } }

Like the title says: Can reflection give you the name of the currently executing method.  I'm inclined to guess not, because of the Heisenberg problem.  How do you call a method that will tell you the current method without changing what the current method is?  But I'm hoping someone can prove me wrong there.  Update:     Part 2:  Could this be used to look inside code for a property as well?   Part 3:  What would the performance be like?   Final Result I learned about MethodBase.GetCurrentMethod().  I also learned that not only can I create a stack trace, I can create only the exact frame I need if I want.    To use this inside a property, just take a .Substring(4) to remove the 'set_' or 'get_'.


Is there built in functionality for the Watch 3 to track my sleep patterns?  Is there anything that figures out sleep cycles and duration, and tracks heart rate at the same time for a prelimnary analysis?

I want to use an Apple Watch 2 to track my sleep. In order to achieve this I will need to wear the Apple Watch during sleep, which creates an issue around battery usage. So my thinking is that I can put the watch on charge twice daily on most days: in the morning while getting ready for work and again at night while getting ready for bed. By doing this I estimate the battery will have enough power to keep the watch going 24/7 on most days.  Obviously this means I need a sleep tracking app to do the tracking. My requirements are:   It must be highly efficient in terms of battery usage It can track sleep while the watch is in Airplane mode It can synchronise data with the iOS Health app on my iPhone It must be able to provide a summary of my sleep on the Apple Watch itself   NOTES:   I do not mind paying for the App if doing so results in me getting a much better product I am open to using 3rd party devices if it means the quality of tracking/measurements are much higher While not a requirement, if the app also supports syncing data with other HealthKit apps that would be a plus   I did consider posting this in the  community, but it didn't seem to have the appropriate tags.


I just switched from Chrome to Firefox and I was wondering if I can get my bookmarks out of Chrome and into Firefox somehow. Is it possible to export to some standard format and import into Firefox?  Thanks

I was a Windows user for last 5 years but wanted to switch into Ubuntu World. I saved too many (around 100) bookmarks into chrome while using Windows. Now I want to import those bookmarks into Ubuntu browser (Firefox).  How can I achieve this?


I'm trying to make a simple 3d game in Processing but I've run into a problem. I tried to make an array to keep track of my environment objects and to make it easier to modify. However, when I try to run the program, it won't work.  Main code:    //arrays BoxCl[] envArr;  void setup() {   size(640, 360, P3D);    envArr[0] = new BoxCl(1,1,-1,1);              //it shows the error here   envArr[envArr.length] = new BoxCl(2,1,-1,1); }  void draw() {   background(0);   camera(mouseX, height/2, (height/2) / tan(PI/6), width/2, height/2, 0, 0, 1, 0);   Update();   Draw(); }  void Update(){  }  void Draw(){   for(BoxCl i : envArr){     i.Draw();   } }   BoxCl Class:  class BoxCl{    float x, y, z;   int s;    BoxCl(float x, float y, float z, int size){     this.x = x;     this.y = y;     this.z = z;     this.s = size;   }    void Draw(){     translate(scale*x, scale*y, scale*z);     stroke(255);     fill(255);     box(s * scale);     translate(scale*-x, scale*-y, scale*-z);   }  }   I've tried looking it up () but I think I'm too inexperienced to understand what I am supposed to do.  Please help.  edit: I am aware that a variable/array/object should be defined before being used. But how do I define the envArr in a way that it can still change? (i.e. increase or decrease in size when I have to create or delete an object)

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


Since TQQQ is 3x the leverage of QQQ, so the conventional wisdom is:  When TQQQ drops 34%, then it is all "wiped out" (meaning a $100 investment will go to $0 now). And TQQQ itself is also all wiped out.  However, let's say, I bought TQQQ when QQQ was at $217, and now QQQ is at $330. So let's say, if some day, QQQ drops from $330 to $217, which is dropping 34%, should my investment in TQQQ get all wiped out?  However, I can also claim that, QQQ went up and then down along that roller coaster, but my TQQQ should just go to my original purchase price.  Or making it more drastic: I bought TQQQ on Monday, and Tuesday, QQQ went up from $217 to $330, and Wednesday, QQQ went from $330 to $217 -- dropping 34%, then my TQQQ should go back to the price of Monday only.  However, if Tom bought TQQQ on Tuesday when QQQ was $330, and then Wednesday, QQQ went from $330 to $217, then by (1) above, shouldn't the invest in TQQQ get all wiped out? (and shouldn't TQQQ itself be completely wiped out?) Or what if on Tuesday, when QQQ is $330, I sold all my TQQQ and get $N, and use that $N to buy back TQQQ (that is like, as if I did nothing really), but then by (1) above and like Tom, my investment in TQQQ should be wiped out, but by (2) above, my investment in TQQQ should just go back to the price I bought on Monday.  So these two points are contradictory.  How does it work?

What happens to the price of the triple-leveraged ETF if the S&P 500 loses more than one-third of its value (i.e., the return is below -33 1/3%)?  Does it mean the value is equal to zero?


I made an application with Mono, and I want it is always running. If my application stopped, I need it to automatically start again. Does anyone have solution that would help me?  Also, how do I start an application at startup?

I need to run a bash script at boot-time as superuser in Xubuntu. I don't know where to start. I have to do something described in a Arch Linux guide. That guide says exactly:     Add following at the end of the file : /etc/rc.sysinit   # Do my action /etc/rc.d/do_my_action  /bin/dmesg >| /var/log/dmesg.log   But I do not have /etc/rc.sysinit and /etc/rc.d/ in Xubuntu. I'm sure there are equivalent ones, right?


I have installed a font, and now I wish to remove it, but I am not sure exactly how. I installed it by opening the .TTF file and clicking the "Install" button. But there is no uninstall button, and no obvious way of uninstalling a font installed in that way.  So my question is really obvious, how do I uninstall a font installed in that way?

There are a lot of extra fonts that all seem to look alike and just annoy me in the drop down list. Is there anyway I can erase them from the system?


I have a mathematical expression, I try to write it in multiple line. I tried: multline, equation + split, align .. .   $\text{max} \left \{frac{1}{2}2x^{2}(2A+6Bx^{-4})+x(2Ax-2Bx^{-3}+\frac{1}{3}-4(Ax^{2}+Bx^{-2}+\frac{1} {3}x+1)+x+4,Ax^{2}+Bx^{-2}+\frac{1}{3}x-Ax^{2}-Bx^{-2}-\frac{1}{3}x-1   \right\}$   Could you please help me?

I have a multi-line equation that I want to have matching sized parentheses. The advice I read online was to use \left( equation \right. \\ left. rest-of-equation \right) . However, this syntax leaves first half of the equation unaware of what is in the second half. For example, if you include a square root term after the break, the second parenthesis will be larger than the opening parenthesis. When you are using the aligned environment to split a long equation this can look somewhat offputting.    Compare the top equation to the bottom one. The parentheses match in size for the bottom equation, but the left hand parentheses for the top one is  noticeably smaller.  Top Code:   \begin{aligned}[t]   \gamma_{\text{u}} + \frac{1}{108}   \left(57\gamma_{\text{er}} \right. &+  38\gamma_{\text{se}}\\ & {}\pm  \left.\sqrt{2601 \gamma_{\text{er}}^2 + 3648  \gamma_{\text{er}}\gamma_{\text{se}} + 1444 \gamma_{\text{se}}^2}  \right)   \end{aligned}   Bottom Code:  \begin{aligned}[t] \gamma_{\text{u}} + \frac{1}{16} \left(9\gamma_{\text{er}}  +  6\gamma_{\text{se}} \pm  \sqrt{49 \gamma_{\text{er}}^2 + 76 \gamma_{\text{er}}\gamma_{\text{se}} + 36 \gamma_{\text{se}}^2} \right) \end{aligned}


I'm currently reading the book 'An Introduction to Statistical Learning with application in R(ISLR)', it is very helpful for learning the applications of statistical model, but less complement of theoreotical content or mathematical proof/derivation of formulas. I'm often confused with some conclusion/formulas provided in that book without theoretical explanation. Does anyone can give me some resources or books that emphasizes on theoretical aspect of statistical learning? Or other statistical learning book with theoretical problems is OK as well.

Every textbook I've seen so far describes ML algorithms and how to implement them.  Is there also a textbook that builds theorems and proofs for the behaviour of those algorithms? e.g. stating that under conditions $x,y,z$, gradient descent will always lead to $A,B,C$?


I know there must be something unmathematical in the following but I don't know where it is: \begin{align} \sqrt{-1} &= i \\\\\ \frac1{\sqrt{-1}} &= \frac1i \\\\  \frac{\sqrt1}{\sqrt{-1}} &= \frac1i \\\\  \sqrt{\frac1{-1}} &= \frac1i \\\\  \sqrt{\frac{-1}1} &= \frac1i \\\\  \sqrt{-1} &= \frac1i \\\\  i &= \frac1i \\\\  i^2 &= 1 \\\\  -1 &= 1 \quad !!? \end{align}


I need to parse my HTML page to replace some links, this is the form of a link Mauris nec. The problem is that my regex expression doesn't end properly, I think it's because of the ".  This is my Regex expression :  Regex r= new Regex("(.*)");   That regex doesn't end after each link, and the third group doesn't contain the title property but almost all the html until the last  of my html.  I tested it with this site :      So, why doesn't the third group end directly after Bas-Rhin" ?

It seems like every question on stackoverflow where the asker is using regex to grab some information from HTML will inevitably have an "answer" that says not to use regex to parse HTML.  Why not? I'm aware that there are quote-unquote "real" HTML parsers out there like , and I'm sure they're powerful and useful, but if you're just doing something simple, quick, or dirty, then why bother using something so complicated when a few regex statements will work just fine?  Moreover, is there just something fundamental that I don't understand about regex that makes them a bad choice for parsing in general?


i get following errors when trying to open programs over ssh.  $ thunar Thunar: Cannot open display:   $ libreoffice  Failed to open display  $ firefox Error: GDK_BACKEND does not match available displays  $ keepassx keepassx: cannot connect to X server   $ keepass2 Unhandled Exception: System.TypeInitializationException: The type initializer for 'System.Windows.Forms.XplatUI' threw an exception. ---> System.ArgumentNullException: Could not open display (X-Server required. Check your DISPLAY environment variable) Parameter name: Display   at System.Windows.Forms.XplatUIX11.SetDisplay (IntPtr display_handle) <0x41b3c8a0 + 0x00b9b> in <filename unknown>:0    at System.Windows.Forms.XplatUIX11..ctor () <0x41b3ab20 + 0x001df> in <filename unknown>:0    at System.Windows.Forms.XplatUIX11.GetInstance () <0x41b3a8d0 + 0x0005b> in <filename unknown>:0    at System.Windows.Forms.XplatUI..cctor () <0x41b3a160 + 0x00137> in <filename unknown>:0    --- End of inner exception stack trace ---   at System.Windows.Forms.Application.EnableVisualStyles () <0x41b38870 + 0x0001b> in <filename unknown>:0    at KeePass.Program.Main (System.String[] args) <0x41b376c0 + 0x0008b> in <filename unknown>:0  [ERROR] FATAL UNHANDLED EXCEPTION: System.TypeInitializationException: The type initializer for 'System.Windows.Forms.XplatUI' threw an exception. ---> System.ArgumentNullException: Could not open display (X-Server required. Check your DISPLAY environment variable) Parameter name: Display   at System.Windows.Forms.XplatUIX11.SetDisplay (IntPtr display_handle) <0x41b3c8a0 + 0x00b9b> in <filename unknown>:0    at System.Windows.Forms.XplatUIX11..ctor () <0x41b3ab20 + 0x001df> in <filename unknown>:0    at System.Windows.Forms.XplatUIX11.GetInstance () <0x41b3a8d0 + 0x0005b> in <filename unknown>:0    at System.Windows.Forms.XplatUI..cctor () <0x41b3a160 + 0x00137> in <filename unknown>:0    --- End of inner exception stack trace ---   at System.Windows.Forms.Application.EnableVisualStyles () <0x41b38870 + 0x0001b> in <filename unknown>:0    at KeePass.Program.Main (System.String[] args) <0x41b376c0 + 0x0008b> in <filename unknown>:0  :06:22 PM~/Documents$ gimp Cannot open display:   $ wireshark QXcbConnection: Could not connect to display  Aborted (core dumped)  $ gedit  Failed to connect to Mir: Failed to connect to server socket: No such file or directory Unable to init server: Could not connect: Connection refused  (gedit:23724): Gtk-WARNING **: cannot open display:    i've always been able to open aplications over ssh, this just started yesterday. using ubuntu 16.04 on both machines.  please DO NOT flag this as a repeat question, the following solutions didn't help:          if specific info is needed, please ask, i'll do my best to answer.

I am trying to run gedit from an SSH terminal on Windows, connected to an Amazon EC2 instance running Ubuntu 12.04 Server and I am getting this error:  Cannot open display:   How do I fix it?


I want to convert the code from C++ to C#, there is one line code regarding with memcpy. Not sure how to convert it.  memcpy(Bucket, nBucket, 4 * L);   The original code is from  I finished most of them except a few lines.

I have 2 objects from the same type and i would like to shallow copy one state to the other. In C++ i have memcpy which is great. How can i do it in C#? The MemberwiseClone() is not good enough because it creates & returns a new object and i like to copy to an existing object. I thought of using reflection but i'm afraid it will be too slow for production code. I also thought of using one of the .Net serializers but i think they also create object rather than setting an existing one.  My Use Case:  I have a template object (class not struct) which needs to be updated by one of its instances (objects made of this template)  Any ideas?


Can you hire a Rental car in Dublin, travel to Scotland,  and return the car to Dublin (the trip would be about a week).

My wife, two kids and I will be traveling in Ireland and the UK Nov. 1st through 21st. We're flying into and out of Dublin. Our plan is to do a clockwise tour: Fly into Dublin -> Belfast -> Scotland -> England/London -> Back to Dublin to fly home.  We've been planning to rent a car when we land in Dublin (doing just things outside Dublin at the start of the trip) and have a car all the way until London, then turn in the car and take a train/ferry to get back to Dublin before flying home.  However, reading through the car rental section of Rick Steve's 2012 Ireland book is causing us to question if this is the right plan.  He says (p. 480):     If your trip covers both Ireland and Great Britain, you're better off   with two separate car rentals, rather than paying for your car to ride   the ferry between the two islands. On an all-Ireland trip, you can   drive your rental car from the Republic of Ireland into Northern   Ireland, but be aware of drop-off charges ($75-150) if you return it   in the North.   So it seems like he recommends against doing one car rental for both islands, but he also recommends against renting in the Republic of Ireland and returning it in Northern Ireland (our other option for our current itinerary).  So we're not sure which is best here.  A few questions about this:   If we do one car rental all the way from Dublin to London, will there be a similar $75-$150 fee? Is there an easy place to return a car on the Northern Ireland side of one of the Northern Ireland -> Scotland ferries, and an easy place on the Scotland side to rent a car?  We'd like to minimize the number of buses/whatever we need to take between car rentals since we'll be lugging around car seats for both of our children (on top of carrying them and our luggage). Will one way be significantly cheaper than the other?  Besides the basic cost of taking the car on the ferry and the drop-off charges, our credit card will cover insurance in Scotland/England but not in Ireland, so we could potentially get a better rental rate by renting a second vehicle once we're on Great Britain. Although, I know you often get a better rate when keeping a car rental for longer, so that may negate any benefit from the credit card covering the insurance.


Let us take this title for example, " The Cars should Be sold in Three Years". If lowercase or uppercase rules are from the Chicago Manual of Style, the word should is lowercase or uppercase?  I have browsed this website and seen , but the answers there do not mention modal verbs.

Are there any concrete rules that say which words (parts of speech) in a title should start with a capital letter? What would be a correct capitalization for the title of this question?


So I know this is a commonly asked question (I've been looking into this for a while now), however, I've been having some issues. I'm inserting a piece of data into my SQLite database, and then I want to retrieve the ID of that newly inserted row. I have a 'globalId' column which is an auto incrementing integer. I've tried many things such as using last_insert_rowid(), getting the max id in the database after inserting it, but neither seem to work.  DBConnection.sql.modifyQuery("INSERT INTO pp_data (...) VALUES (...)");  is my modifyQuery, I've replaced all the actual data with ... because there's a lot of stuff. I then have a readQuery method which will return a ResultSet, and with that, I need to get the column Id.  Thanks in advance!

What's the best way to get the last inserted id using sqlite from Java? Google is giving me different answers--some say select the last-insert-rowid; others say call statement.getGeneratedKeys(). What's the best route to take? (I just want to return the id, not use it for other inserts or anything.)


We know that an additive identity in a ring is always a multiplicative annihilator. But this doesn't need always be true in case of a semiring. Consider that $e$ is the additive identity of a semiring $S$, then for any $a\in S$, we see that $a.e=a.(e+e)=a.e+a.e \implies a.e=e \iff -a.e \in S.$ Looking for a better suggestion.  Thanks

What is an instructive example of a set $X$ equipped with two monoid structures $(X,+,0)$, $(X,\cdot,1)$, such that $+$ is commutative, the distributive laws hold, but $0 \cdot x = 0$ or $x \cdot 0 = 0$ do not hold?  Notice that in case these two absorbing laws hold, one calls $(X,+,0,\cdot,1)$ a semiring. At first sight, it might be surprising that these laws have to be imposed, but this is quite natural from a more general point of view, namely the multiplication $\cdot : X \times X \to X$ should be an additive monoid homomorphism in each variable, and it is known that one has to demand that monoid homomorphisms preserve the neutral element.


LastPass Sesame (Ubuntu/Debian) Sesame was working normally before the new Ubuntu update 15.10. However, now I get this error when I try to execute the command.  John@John's-PC:/media/crypt1$ ./sesame_x64 ./sesame_x64: error while loading shared libraries: libssl.so.0.9.8: cannot open shared object file: No such file or directory  So, I did a clean install following the instruction below.   Right-click the download button and choose 'Save Link As' Extract the tar.bz2 file Run 'sudo apt-get install ca-certificates libssl0.9.8' to update necessary packages   When I run the sudo apt-get install ca-certificates libssl0.9.8, I get this message:Reading package lists... Done Building dependency tree Reading state information... Done Package libssl0.9.8 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  N: Ignoring file 'getdeb.list.bck' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension N: Ignoring file 'getdeb.list.bck' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension E: Package 'libssl0.9.8' has no installation candidate Anyone know how to fix this problem?   Thanks so much!

What does the above Error mean? What is an installation candidate?  I was trying to do  sudo apt-get install munin-memcached     and I get this message:  Reading package lists... Done Building dependency tree        Reading state information... Done Package munin-memcached is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source E: Package munin-memcached has no installation candidate   I googled for the problem and someone said to do a apt-get upgrade but it still did not solve my problem.


So I am an active contributor of Stack Overflow in Russian and I joined the election this year. Because of my ban on MSE (damn it! ;)) my candidacy was removed from the election. But I found out that I can rejoin the election! I'm gonna add some images:       I guess it is a bug, isn't it? Or is it the... the... SECOND CHANCE ? ?? ;) P.S I tried to add my candidacy just to test SE for a bug. Wha? Wha? NO! I'm not cheatin' ;)

We're having , and this week, nominations opened up. A user nominated themselves, but they've been suspended elsewhere on the network and are currently suspended on a different site; as per , a Community Manager went through the nomination removal process. For various reasons, the user is now suspended on Worldbuilding, too - the site having the election. As of yesterday, their nomination was gone, after it had been reposted, and they were (and still are) suspended. The thing is, their nomination is back . . . again ().  The user normally has enough rep to run, but when they're suspended, their rep is reduced to 1 . . . which is obviously not enough meet the minimum requirements to run in an election. I would think the system would automatically see that they have only 1 reputation point if they tried to nominate - let alone re-nominate - and prevent them from nominating . . . which didn't happen.  I'm reporting this as a bug; if it's not a bug, I'd like to make a feature request that users be automatically prevented from running for moderator if they're currently suspended on the site. I can't trust someone as a moderator if in the middle of the election, they're suspended.


In many definitions of O(n log(n)), I typically see as a requirement that the subproblem must be a division of the original problem size by two. However, in particular, I have seen that O(log(n)) need only be a problem of reducing size.   Do we necessarily need to divide the problem into halves to get a problem of nlog(n)?  Or could it be merely a reductive problem? Like so:  for (i = 0; i < A.length(); i++) {     for (j = i; j < A.length(); j++)     {         //do something     } }   Would something like this also be categorized as n(log(n))? Or is it closer to O(n^2)?

I need to calculate the time complexity of the following code:  for (i = 1; i <= n; i++) {   for(j = 1; j <= i; j++)   {    // Some code   } }   Is it O(n^2)?


This is the content of a text file, and I want to only keep BMP.  这是无效的字符  𡛂 这是正常的字符  哈   In the , I find there is a solution, but it doesn't work here.  iconv -f utf-8 -t utf-8 -c test.txt     The utf-8 of 𡛂 is F0A19B82 (located in CJK Unified Ideographs Extension B), utf-8 of 哈 is E59388（located in CJK Unified Ideographs).  If I want to delete all characters(the size greater than 3 Bytes) like 𡛂 in text file , how to do it?

Is there a way to match some Unicode range exactly. Let's use the  as an example: U+400 to U+52f  The whole range of chars could be printed (from bash or zsh) with:   $ echo -e $(printf '\\U%x' $(seq 0x400 0x52f)) ЀЁЂЃЄЅІЇЈЉЊЋЌЍЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюяѐёђѓєѕіїјљњћќѝўџѠѡѢѣѤѥѦѧѨѩѪѫѬѭѮѯѰѱѲѳѴѵѶѷѸѹѺѻѼѽѾѿҀҁ҂҃҄҇ҊҋҌҍҎҏҐґҒғҔҕҖҗҘҙҚқҜҝҞҟҠҡҢңҤҥҦҧҨҩҪҫҬҭҮүҰұҲҳҴҵҶҷҸҹҺһҼҽҾҿӀӁӂӃӄӅӆӇӈӉӊӋӌӍӎӏӐӑӒӓӔӕӖӗӘәӚӛӜӝӞӟӠӡӢӣӤӥӦӧӨөӪӫӬӭӮӯӰӱӲӳӴӵӶӷӸӹӺӻӼӽӾӿԀԁԂԃԄԅԆԇԈԉԊԋԌԍԎԏԐԑԒԓԔԕԖԗԘԙԚԛԜԝԞԟԠԡԢԣԤԥԦԧԨԩԪԫԬԭԮԯ   $ a=$(zsh -c 'echo -e $(printf '\''\\U%x'\'' $(seq 0x400 0x52f))')     To filter some range of it, lets use 0x452 to 0x490, this is the expected output:  $ b=$(bash -c 'echo -e $(printf '\''\\U%x'\'' $(seq 0x452 0x490))') $ echo "$b" ђѓєѕіїјљњћќѝўџѠѡѢѣѤѥѦѧѨѩѪѫѬѭѮѯѰѱѲѳѴѵѶѷѸѹѺѻѼѽѾѿҀҁ҂҃҄҇ҊҋҌҍҎҏҐ $ echo "$b" | xxd 00000000: d192 d193 d194 d195 d196 d197 d198 d199  ................ 00000010: d19a d19b d19c d19d d19e d19f d1a0 d1a1  ................ 00000020: d1a2 d1a3 d1a4 d1a5 d1a6 d1a7 d1a8 d1a9  ................ 00000030: d1aa d1ab d1ac d1ad d1ae d1af d1b0 d1b1  ................ 00000040: d1b2 d1b3 d1b4 d1b5 d1b6 d1b7 d1b8 d1b9  ................ 00000050: d1ba d1bb d1bc d1bd d1be d1bf d280 d281  ................ 00000060: d282 d283 d284 d285 d286 d287 d288 d289  ................ 00000070: d28a d28b d28c d28d d28e d28f d290 0a    ...............     But it seems impossible to filter with sed. This doesn't work:  $ echo "$a" | sed 's/[^\x452-\x490]//g'   Nor this (the result match other characters (probably a collating issue)):  $ echo "$a" | sed $'s/[^\u452-\u490]//g' АБВГжзийклмнопрстуфхцчшщъыьэюяёђєѕіїјљњћќѝўџҋҍҏҐҗҙқҝҟҡңҥҧҩҫҭүұҳҵҷҹһҽҿӂӄӆӈӊӌӎӐӒӔӝӟӡӣӥӧөӫӭӯӱӳӵӹԅԇԉԋԍԏ   Not even this (same collating issue):  $ echo "$a" | sed 's/[^ђ-Ґ]//g'   This work with awk:  $ echo "$a" | awk '{gsub(/[^ђ-Ґ]/,"")}1'   But the only way to use an hex range is to use shell to convert hex to an unicode character  $ echo "$a" | awk $'{gsub(/[^\u452-\u490]/,"")}1'   or (two solutions):  $ c=$(bash -c 'printf "\u452-\u490"')  $ echo "$a" | awk '{gsub(/[^'"$c"']/,"")}1' $ echo $a | awk -v ra="[^$c]" '{gsub(ra,"")}1'   Questions:   Is there a way to do this with sed? Could awk do it in hex numbers without a higher shell. If possible, what is exactly the range matched by the collating sequence that sed use with sed 's/[^ђ-Ґ]//g'.   P.S.: I know that could be done in perl, thanks.


I'm trying to learn how RSA works. From what I found online, I'm supposed to  generate private key using Extended Euclidean algorithm.  I've managed to generate the public key, but don't know how to use EEA to generate the private key. How should I exactly input into EEA, and how to process the output?

When given $p = 5, q = 11, N = 55$ and $e = 17$, I'm trying to compute the RSA private key $d$.  I can calculate $\varphi(N) = 40$, but my lecturer then says to use the extended Euclidean algorithm to compute $d$. That's where I get stuck.    Here's my work so far:  First I use the Euclid algorithm to calculate:  40 = 2(17) + 6  17 = 2(6) + 5 6 = 1(5) + 1 = gcd   So I know the GCD is 1. Applying the 'extended' section of the algorithm:  6 = 40-2(17) 5 = 17-2(6) 1 = 6-1(5) 1 = 6-1(17-2(6)) 3(6) = 1 (17) 3(40 - 2(17)) - 1(17) 3(40) - 3(17)   I know the answer is $33$, but I have no idea how to get there using the extended Euclidean algorithm. I can't figure out why I'm getting $3(40) - 3(17)$ when I know the answer should contain $33$.


I have time value from server returned as 13:00:45:888 which is returned as TIME value from SAP backend . How can I convert it to 01:00 PM

How to format correctly according to the device configuration date and time when having a year, month, day, hour and minute?


I need to prove  $$\lim\limits_{n\to\infty} \left( 1-\frac{1}{n} \right)^n = \frac{1}{e}$$ For now, I only know the e definition: $\lim\limits_{n\to\infty} \left ( 1+\frac{1}{n} \right)^n = e $, and I need to proof all the partial results in between to reach the wanted result.

Q1: Could someone provide a proof for this equation (please focus on this question):   $$e^z = \lim \limits_{x \rightarrow \infty} \left( 1 + \frac{z}{x} \right)^x$$  Q2: Is there any corelationn between above equation and the equation below (this would benefit me a lot because i at least know how to proove this one):  $$e = \lim \limits_{x \rightarrow \infty} \left( 1 + \frac{1}{x} \right)^x$$


\documentclass{article} \usepackage{amsmath} \usepackage[noend]{algpseudocode} \usepackage{algorithm}  \makeatletter \def\BState{\State\hskip-\ALG@thistlm} `\makeatother  \begin{document} \begin{algorithm} \caption{AIP}\label{euclid} \begin{algorithmic}[1] \State \textit{$\sum^{N_agent}_{i=1}$$L_A$} $\gets$ position of \textit{$agent_i$} \BState \emph{loop}: \State \textit{$i$}$\gets one \State \textit{$i$ plus one} \If {\textit{distance(eNB,$L_i$)} $< \delta$} \textit{close $agent_i$} \IF {\textit{distance(eNB,$L_i$)}$>\Delta$} \textit{$agent_i$ power equals P$} \State \textbf{goto} loop  \end{algorithmic} \end{algorithm} \end{document}   Can someone help me compile this successfully?

I have to use algpseudocode package to improve my paper look like more professional   But I can't compile successfully.  \usepackage{amsmath} \usepackage{algorithm} \usepackage[noend]{algpseudocode}  \makeatletter \def\BState{\State\hskip-\ALG@thistlm} \makeatother  \begin{document} \begin{algorithm} \caption{AIP}\label{euclid} \begin{algorithmic}[1] \Procedure{MyProcedure}{} \State $\textit{locationAgent} \gets \text{position of }\textit{{agent}}$ \State $\textit{locationMD} \gets \text{position of }\textit{{MD}}$ \If {\textit{distance(eNB,$agent_i$)}}>$\delta$ \BState \emph{loop}: \State $j \gets \textit{patlen}$ \If {$\textit{string}(i) = \textit{path}(j)$}\Return TURE \State $j \gets j-1$. \State $i \gets i-1$. \State \textbf{goto} \emph{loop}. \State \textbf{close}; \EndIf \State $i \gets i+\max(\textit{delta}_1(\textit{string}(i)),\textit{delta}_2(j))$. \State \textbf{goto} loop \EndProcedure


In Game of Thrones s05e10      Sansa Stark and Theon Greyjoy (Reek) jump off the wall of Winterfell to escape Ramsay Bolton.    In the scene the wall looked rather high and even though the ground was covered by snow, I just can not believe they would have survived that jump. Even if  survival is possible, they should have had a couple broken bones, especially their legs.  So how did they make that jump and were able to keep traveling after it?

We could see that Theon Greyjoy helped Sansa Stark escape from Winterfell which was under Ramsay's control by jumping off the wall. The outer wall is said to be about 80 feet high. How did both of them survive jumping from that height? It is highly unlikely to survive that jump even if there was snow.


I have 2 monitors, when I open the start screen it does only open on 1 monitor. Is there a way to have the start screen displayed on both monitors at the same time (like an extended start screen)?

Is the Windows8 start screen capable of spanning 2 monitors?  This is not a question of multiple monitor support; this is a question of whether the Windows-8 start screen is able to display across 2 monitors, not as a mirrored display but as a additive display to the width of the single screen start screen.   Or, does a app exist that I can purchase for it to do this?


I've been trying to solve this for hours, but I just can't seem to do it. And yes, I know I have to show that $(k+2)^{\frac{1}{k+2}} < ... < (k + 1)^{\frac{1}{k+1}}$ from the starting assumption that $(k+1)^{\frac{1}{k+1}} < k^{\frac{1}{k}}$. Any hints would be highly welcome.

I am currently helping a friend of mine with his preperations for his next exam. A big topic of the exam will be induction, thus I told him he should practice this a lot. As at the beginning he had no idea how induction worked, I showed him some typical examples.  Now he showed me an exercise he was having trouble with, which states that one should prove $$n^{n+1} > (n+1)^n$$  for all $n \geq 3$. I have to admit that I too have trouble showing this inequality, as in all of my attempts, my lower bound is too low. Also, I have not yet figured out, how one gets the $(n+2)^{n+1}$, primarely the number $2$ is a problem. I think this might be solved using the binomial theorem, however, I don't think they have already seen the binomial theorem in school.  Is there an easy method to show this inequality by induction not using the binomial theorem? If no: How can one show it using the binomial theorem?  Thanks for answers in advance.


Does anyone know why bringing the limit inside the sum doesn't work sometimes, other than the fact that sometimes the resulting answer contradicts the answer when the limit is not inside the sum?

I have seen that the method of "dominated convergence" implies that sometimes a limit cannot be brought inside of a sum, but is there a more basic way to understand this, preferably without using integrals?   A conceptual or simple answer would be helpful. Thank you!


I installed Universal Media Server 3.6 on ubuntu 14.04 desktop. What I want to do is, to launch it during startup. How to add this into startup? Any suggestions? Thanks in advance.

How can I make an application automatically start when I have logged in?


I have been studying the Riemann zeta function and I came across such a representation of zeta function  $\zeta(s)=(1-2^{1-s})^{-1} \sum_{n=1}^{\infty} (-1)^{n-1} n^{-s}$.  Then it says in the book that this alternating series converges for $Re(s) > 0$. And there is my question. How can we show that this series converges in that region? We can't use the alternating series test because we deal with complex numbers, but please correct me if I'm wrong, so how can we do it? Also, could anyone explain to me or recommend any book to read why the imaginary part does not have any impact on convergence of a series? Thanks!

If $$\sum_{n=1}^{\infty} \frac{a_{n}}{n^{s}}$$ Converges( s is real) and $\operatorname{Re}(z)>s$.  Then $$\sum_{n=1}^{\infty} \frac{a_{n}}{n^{z}}$$ also converges.  $a_n$ is complex sequence.


I am trying outsmart these tragic systems designed in hell knows when. I managed to nail this last year, but this year Lufthansa seems to killed it. Allow me to explain.  I have to get pretty much all across the world from Lithuania to New Zealand. Last year I managed to book this in one lump via Lufthansa with 1 week layover in Singapore and months later with a week long layover in Tokyo (both legs stopping in Frankfurt).  This year I am trying to replicate something similar but stop in Malaysia, Bangkok or Singapore, but looks like Lufthansa site claims The selected route cannot be booked online or is not served by Lufthansa. Although booking flight straight from Vilnius to Auckland works (but obviously I do not want 33hr long journey with no break).  Booking thru Thai Airways site could almost work, but then they do not even recognise Vilnius as a city. Booking from Air New Zealand does not allow to start your multi-part journey from Europe. Epic fail.  I have tried using these awful, awful world-the-globe pages from both alliances which seem to be broken (would never complete the journey). Sites like Skyscanner or Kayak suggest flying via Russia (lol).  Is there a site that I am missing, perhaps some more advanced alliance search tool? Please help me tackle this problem. I do not want to pay thousands of dollars for what is worth around €1.5k.  Edit: David asked for more information why I think that sites are awful. Well, first of all, none of them allow to search actual multipart flights. One World round the world tool only lets you fly one direction (literally round the world! haha, you get it guys!). Star Alliance doesn't even work without Flash player. In year 2015, trillion dollar business is using web technology that is decade old (the rest looks like its build on IBM's WebSphere, so theres another few hundred million of expenditures).

Is there a search engine that considers "mix&match" flight combinations?  My current problem: I need to go from FRA to YLW (Frankfurt/Germany to Kelowna/Canada) on July 29th, and arrive no later than 5pm. The search engines I checked only offer €3000+ flights.  I found a 2-stop combo through LHR and YVR for half that price. I'll probably have to check my baggage out and back in twice, but if the layover times are long enough, who cares?  A real search engine could find that for me (or something that's even better). Or, hell, give me a place to bulk-download the flight schedules from and I'll program it myself (of course I'd also need a way to check seat availability …).  Update: Please read before answering. A search engine which does this should, at minimum, show the flight combination through LHR which I found manually. Note that I need to arrive before 5pm, on the same day.  Also note that this is a generic question; I'm not looking for a specific good flight here -- but the details are useful to illustrate whether an answer is actually valid. :-/  NB: Typo, should have been July 29th.


I get this after rsync the .sh file to the server:  sudo: unable to execute ./run_vps_post_config.sh: No such file or directory   To fix, I open the file with winscp and save it. Then it runs again. (this is nothing to do with permissions. It runs ok.)  Same thing happens when I zip->rsync->unzip. However if I unzip with -aa option (treat ALL files as text), then it is OK.  I looked in rsync for a similar option to treat files as text, but none was found.

When I copy my bash script across from Notepad++ into a new file with nano editor inside SSH and save. It runs fine. (sh ./install).   But if I save the file (Exact same contents), upload to my web server, download it using Wget on the same machine. I get syntax errors. I've checked the encoding and they seem to be the same. I have since used a plethora of character encoding to see if it will resolve the issue. I am also setting the file to executable once I download it using wget!  The file runs fine and I have zero errors when copy and pasting using nano. Any idea what this may be?


Trying to reuse an existing "SysV" init script with new Linux version that uses "systemd" (RHEL 7). Just copying it into "/etc/init.d/" fails to work as expected. Can only manually Start/Stop service using the commandline as if the script was a user file. The systemd enable and start/stop fail.  Where should "SysV" init scripts be copied to on a system that is using systemd ? Where should any custom systemd scripts for system/user service daemons be created ? What are common problems found or required actions before I can use the old init scripts with the new systemd ?

I have 2 graphics cards on my laptop. One is IGP and another discrete.   I've written a shell script to to turn off the discrete graphics card.  How can I convert it to systemd script to run it at start-up?


Let $f(z)$ be a positive harmonic function on the unit disk such that $\frac{1}{f(z)}$ is also harmonic. Show $f(z)$ must be constant.

Is it true that a positive harmonic function on $\mathbb{R}^n$ must be a constant? How might we show this? The mean value property seems not to be the way...for that we would need boundedness.


I have a char[] that I am attempting to append values to. However, at the line newStringAr[count] = ar[j][i], I am receiving an error:  java.lang.NullPointerException: Attempt to invoke virtual method 'char java.lang.Character.charValue()' on a null object reference.   When I changed my array to a Character[], this error was resolved, but then I was not able to convert my array to a string as shown in the last line of the code sample below. How can I resolve this issue?  Note that ar is a previously-defined array of Characters (Character[] not char[]).      int count = 0;     char[] newStringAr = new char[ch.length];      for (int i = 0; i < ar.length; i++) {         for (int j = 0; j < ar.length; j++) {             if (count<ch.length) {                 newStringAr[count] = ar[j][i];                 count++;             }         }     }      String out = new String(newStringAr);

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


So simple:  Will this sail-based moving system work? Why?

How it this possible? Even if the gif is fake, the Mythbusters did it and with a large sail it really moves forward. What is the explanation?


For a UART that takes baud as generic, I want to prevent design compilation in modelsim and quartus ii if the baud rate is not in specific range. The baud rate is passed as a generic.  One option is to enum for baud rate so this problem does not arise. But provided that I use the natural type, how do I prevent design compilation using assert if the baud rate is wrong?  I could write a function that will determine if baud rate is correct.

I have a parameterised module in verilog, where the parameters are a clock rate and refresh rate, which is used to calculate how many cycles of inactivity are inserted between instances of a repeating operation.  However, it is very easy to set parameters that cannot be attained (because the operation takes a non-trivial length of time, so the repeat would have to occur before it had completed), and at the moment the design does not give any feedback on this.  I was wondering if there was some way I could trigger an error during synthesis (or compilation prior to simulation) if the conditions cannot be met (i.e. if one localparam is less than another)?  Some equivalent of the popular C/C++ compile-time-assert hack, perhaps.


I am beginner i want to get text in EditText and compare it with another string .  I want to check if text writed in EditText is equals a 'String' then show a Toast but it is not working   I debug and check the value of both are exactly admin but if block is not working and shows else block.  if (editText.getText().toString() == "admin") {     //Never enter this block when i type "admin" in the EditText.     Toast.makeText(MainActivity.this,"ok",Toast.LENGTH_LONG).show(); } else {     Toast.makeText(MainActivity.this,"Wrong User Or Pass", }

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


I am working on AIX unix and trying to remove non-printable characters from file the data looks like Caucasian male lives in Arizona w/ fiancÃÂÃÂÃÂÃÂÃÂ in file when I view in Notepad++ using UTF-8 encoding. When I try to view file in unix I get ^▒▒^▒▒^▒▒^▒▒^▒▒^▒▒ instead of the special characters.  I want to replace all those special characters with space.  I tried sed 's/[^[:print:]]/ /g' file but it does not remove those characters.My locale are listed below when I run locale -a  C POSIX en_US.8859-15 en_US.ISO8859-1 en_US   I even tried sed -e 's/[^ -~]/ /g' file and it did not remove the characters.  I see that others stackflow answers used UTF-8 locale with GNU sed and this worked but I do not have that locale.  Also I am using ksh.

Is there a way to match some Unicode range exactly. Let's use the  as an example: U+400 to U+52f  The whole range of chars could be printed (from bash or zsh) with:   $ echo -e $(printf '\\U%x' $(seq 0x400 0x52f)) ЀЁЂЃЄЅІЇЈЉЊЋЌЍЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюяѐёђѓєѕіїјљњћќѝўџѠѡѢѣѤѥѦѧѨѩѪѫѬѭѮѯѰѱѲѳѴѵѶѷѸѹѺѻѼѽѾѿҀҁ҂҃҄҇ҊҋҌҍҎҏҐґҒғҔҕҖҗҘҙҚқҜҝҞҟҠҡҢңҤҥҦҧҨҩҪҫҬҭҮүҰұҲҳҴҵҶҷҸҹҺһҼҽҾҿӀӁӂӃӄӅӆӇӈӉӊӋӌӍӎӏӐӑӒӓӔӕӖӗӘәӚӛӜӝӞӟӠӡӢӣӤӥӦӧӨөӪӫӬӭӮӯӰӱӲӳӴӵӶӷӸӹӺӻӼӽӾӿԀԁԂԃԄԅԆԇԈԉԊԋԌԍԎԏԐԑԒԓԔԕԖԗԘԙԚԛԜԝԞԟԠԡԢԣԤԥԦԧԨԩԪԫԬԭԮԯ   $ a=$(zsh -c 'echo -e $(printf '\''\\U%x'\'' $(seq 0x400 0x52f))')     To filter some range of it, lets use 0x452 to 0x490, this is the expected output:  $ b=$(bash -c 'echo -e $(printf '\''\\U%x'\'' $(seq 0x452 0x490))') $ echo "$b" ђѓєѕіїјљњћќѝўџѠѡѢѣѤѥѦѧѨѩѪѫѬѭѮѯѰѱѲѳѴѵѶѷѸѹѺѻѼѽѾѿҀҁ҂҃҄҇ҊҋҌҍҎҏҐ $ echo "$b" | xxd 00000000: d192 d193 d194 d195 d196 d197 d198 d199  ................ 00000010: d19a d19b d19c d19d d19e d19f d1a0 d1a1  ................ 00000020: d1a2 d1a3 d1a4 d1a5 d1a6 d1a7 d1a8 d1a9  ................ 00000030: d1aa d1ab d1ac d1ad d1ae d1af d1b0 d1b1  ................ 00000040: d1b2 d1b3 d1b4 d1b5 d1b6 d1b7 d1b8 d1b9  ................ 00000050: d1ba d1bb d1bc d1bd d1be d1bf d280 d281  ................ 00000060: d282 d283 d284 d285 d286 d287 d288 d289  ................ 00000070: d28a d28b d28c d28d d28e d28f d290 0a    ...............     But it seems impossible to filter with sed. This doesn't work:  $ echo "$a" | sed 's/[^\x452-\x490]//g'   Nor this (the result match other characters (probably a collating issue)):  $ echo "$a" | sed $'s/[^\u452-\u490]//g' АБВГжзийклмнопрстуфхцчшщъыьэюяёђєѕіїјљњћќѝўџҋҍҏҐҗҙқҝҟҡңҥҧҩҫҭүұҳҵҷҹһҽҿӂӄӆӈӊӌӎӐӒӔӝӟӡӣӥӧөӫӭӯӱӳӵӹԅԇԉԋԍԏ   Not even this (same collating issue):  $ echo "$a" | sed 's/[^ђ-Ґ]//g'   This work with awk:  $ echo "$a" | awk '{gsub(/[^ђ-Ґ]/,"")}1'   But the only way to use an hex range is to use shell to convert hex to an unicode character  $ echo "$a" | awk $'{gsub(/[^\u452-\u490]/,"")}1'   or (two solutions):  $ c=$(bash -c 'printf "\u452-\u490"')  $ echo "$a" | awk '{gsub(/[^'"$c"']/,"")}1' $ echo $a | awk -v ra="[^$c]" '{gsub(ra,"")}1'   Questions:   Is there a way to do this with sed? Could awk do it in hex numbers without a higher shell. If possible, what is exactly the range matched by the collating sequence that sed use with sed 's/[^ђ-Ґ]//g'.   P.S.: I know that could be done in perl, thanks.


I try to run git pull command with loging output message to file every 5 minutes.  But i got error like this,  (root) CMD (cd /var/www/sites/ && git pull origin master | sed -e "s/^/$(date +\") (CRON) error (grandchild #1111 failed with exit status 2)   My cronjob command as follows.  */5 * * * * cd /var/www/site/ && git pull origin master | sed -e "s/^/$(date +\"%d-%m-%y\ %T\"), /" >> /var/log/crond/site.log   How can fix it?

I want to create a log file for a cron script that has the current hour in the log file name. This is the command I tried to use:  0 * * * * echo hello >> ~/cron-logs/hourly/test`date "+%d"`.log   Unfortunately I get this message when that runs:  /bin/sh: -c: line 0: unexpected EOF while looking for matching ``' /bin/sh: -c: line 1: syntax error: unexpected end of file   I have tried escaping the date part in various ways, but without much luck. Is it possible to make this happen in-line in a crontab file or do I need to create a shell script to do this?


To save myself some keystrokes, I tried to define an abbreviation for \begin{align} and \end{align}  \documentclass[reqno, 11pt]{article}  \usepackage{amsmath, amsfonts, mathtools, amsthm} \usepackage{fullpage}  \newcommand{\ba}{\begin{align*}} \newcommand{\ea}{\end{align*}}  \title{Article Template} \author{You}  \begin{document} \maketitle  \section*{3} \ba e=mc^2 \ea \end{document}   For some reason, the abbreviation for \begin{align} seems to work, but the abbreviation for \end{align} does not. I thought perhaps that \ea was already in use, but tweaking the name didn't change anything. Any ideas?

I have  created some new short command using \newcommand in the following example:  \documentclass[12pt,twoside,a4paper]{book}       \usepackage{enumerate,amsmath}    \newcommand{\ba}{\begin{array}}      \newcommand{\ea}{\end{array}}    \newcommand{\ben}{\begin{enumerate}}       \newcommand{\een}{\end{enumerate}}    \newcommand{\bal}{\begin{align}}       \newcommand{\eal}{\end{align}}    \newcommand{\bc}{\begin{center}}      \newcommand{\ec}{\end{center}}    \newcommand{\de}{^\circ}    \begin{document}       \bc       $5\de$       \ec    \ben       \item Text   \item Text   \een     $\ba{cc}     a & b\\    c & d     \ea$     \bal       & r\\       & f       \eal     But     \begin{align}      & r\\       & f      \end{align}    is working.      \end{document}   All \newcommands are working well except  \bal and \eal. I don't know why it is not working.


There has been a trend now two persons downvote it then it goes on like that. So let there be down voting but do not display the downvotes till the user votes on it. Else the user reads it with an impression that the question is not good.  Am I missing something?

I don't like seeing negative score as the value of a question. I don't know, maybe it's just me, but it just does not look good when a question has a -1 or -5 score.  This is especially annoying when someone adds a negative vote to your question. I even feel offended when my own question suddenly becomes a -1 or lower.  I have a feature request: Allow negative votes as before but when displaying a score, show the 0 score instead.   This may be implemented easily like score=max(0, score) or something like that.  The negative votes will still be allowed but will only affect questions that already have some positive score, will have no affect on 0 scored questions.  What do you think?


I followed the Pierre Hermé éclairs recipe:     60mL water    75mL whole milk    3g salt    3g caster sugar    56g butter    75g flour    A little over 2 eggs   I did the recipe and it called for 45 minutes of baking at 185°C.  I baked them for 40 minutes and left them in the oven for an extra 10 minutes before removing them.  The result was that the exterior was terrific, but the inside was too doughy and I couldn't fill it with crème pâtissière (custard).  Is skipping the 5 last minutes of baking the reason it failed?

Last time I tried to make Chocolate eclairs (similar to cream puffs), the choux pastry just sat in the oven and basically fried.  It didn't rise/grow and so I couldn't hollow out the shells.  Any suggestions?  Recipe was from The Australian Women's Weekly Original Cookbook (Golden Press Pty Ltd, 1977) p. 204  It is almost identical to the one published on their website , with the exception that the cookbook recipe used 1C water and 1C plain flour.


I'm new on Ubuntu 14.04 LTS (64bit) and I'm just getting a hold of this new way of doing things.  I am using a program built for UNIX and I managed to install it and get it all work perfectly, but I am a little bit lazy so I'm trying to figure out a way to make an application shortcut just by double clicking on it (without using Teminal to go to the path and then typing the command for the program).  The command after I get into the right path:  java -cp jts.jar:total.2013.jar -Xmx512M -XX:MaxPermSize=128M jclient.LoginFrame .   Please try to make it as detailed as poosible because, as I said, I'm very new at this.

In older versions it was easy to create a launcher on my desktop. All I had to do is right click on my desktop and select the "create launcher" option.  How can I create such launchers now?


The power category in GNOME Tweaks only show a "suspend when laptop lid is closed". However, there is no distinction between whether the laptop is plugged (for instance to a docking station or a charger) or operating on battery power.  In my case, I would like my laptop to suspend when closing the lid on battery power, but leave it when plugged to its charger. Is there a way to achieve that?

In Ubuntu versions before Gnome Shell, I could set what I wanted to happen when I close the laptop lid depending on whether the laptop is connected to power or not.  Now the default is standby which I can disable in Gnome Tweak Tool. My preferred setting is to only go to standby when on battery and stay on when connected to AC.  Using systemd I only know of options to completely enable or disable lid-actions alltogether. How did Unity solve this in Ubuntu 17.04?


I'm asking more about what this means to my code.  I understand the concepts mathematically, I just have a hard time wrapping my head around what they mean conceptually.  For example, if one were to perform an O(1) operation on a data structure, I understand that the number of operations it has to perform won't grow because there are more items.  And an O(n) operation would mean that you would perform a set of operations on each element.  Could somebody fill in the blanks here?   Like what exactly would an O(n^2) operation do? And what the heck does it mean if an operation is O(n log(n))? And does somebody have to smoke crack to write an O(x!)?

I'd prefer as little formal definition as possible and simple mathematics.


I have written a letter and I want to cite the references of my paper. However, I don't want the reference section to appear at the end of my letter. How can I hide this section?  I have used the \begin{thebibliography} and \bibitem for the references and I am citing them by \cite{marcam2(alfa)}.  \begin{thebibliography}{1}  \bibitem{marcam2(alfa)} M. Abramowitz and I. A. Stegun, {\it Handbook of mathematical functions with formulas, graphs, and mathematical tables}. U. S. Department of Commerce, 1972. \bibitem{choi(2u)} H. Bolcskei, R. U. Nabar, O. Oyman and A. J. Paulraj, `` Capacity scaling laws in MIMO relay networks, " {\it IEEE Trans. Wireless Commun}., vol. 5, no. 6, pp. 1433-1444, June 2006. \end{thebibliography}

How do you produce a document with citations (\citep, \citet) working properly in the paper but without a bibliography at the end?  I've come up with one solution that is bad because it breaks my makefile.  latex file.tex bibtex file # comment out \bibliography{} command latex file.tex   Similarly, is there a way to produce the bibliography with no accompanying text?  Again, I've come up with a solution: fill an otherwise blank .tex file with \nocite{} commands.  However, this is a pain because I have to keep two files synced by hand (and regular expressions to search for \citep{author1, author2} can be a huge pain when there are pagebreaks...).


I'm curious about whether to use comma before "and". Some people told me that using comma to connect two different sentences and two different subjects.   Please provide some examples to explain the usage of this. Thanks a lot!

Should I put a comma before the last item in a list?     I would like crackers, cheese and some soda.   I would like crackers, cheese, and some soda.


Can I use software designed for power saving on laptops on Home PC. (not a laptop) Or maybe someone could suggest alternative tools designed for saving power on PC desktop? What are the other steps required to reduce energy consuming under Ubuntu?

I'm trying to install the Jupiter power settings app but, I read it is no longer compatible with the new kernel. Is there a similar program or a way to manage the power settings on 13.04?


I have a circuit which has uC, Bluetooth module and some other ICs. Current consumption of it varies between 100uA and 20mA. I want to see current waveform using oscilloscope. I worked before high current measurement(above 1Ampere) using low-side sensing technique but not so small this. How to setup a small circuit to see current values of each phase(sleep, active, transmission) separately?       Note: The circuit is powered by battery

This might be old news in a half a decade or two but by today's means, I am referring to electronic prototypes and designs which would draw in a μA (uA) and even nA range of current.  Some recent MCUs, such as SAMD21 that I am using atm are armed with internal clocks such as ,always on, Ultra Low Power Internal 32kHz RC Oscillators which would draw only 125nA, and the whole microcontroller is capable of consuming only 6.2μA on STANDBY mode with a live RTC.   In these type of quiescent current and power consumption levels the smallest limitations in the internal machinery of bench measurement devices such as multimeters and oscilloscopes could add a fair bit of error to the overall measurement or even measure a flat out wrong value in situations like a different relay kicking in when changing the resolution from 6 to 8 decimal places accuracy on your multimeter.   What is the most precise method of measuring the overall quiescent current/power consumption for such applications?     Update:  As I mentioned in one of the replies, measuring low currents is hard but very possible, however, making conclusions on the integrated amount of current consumption to come up with numbers for the realistic over all power consumption is more what I had in mind.  I have bumped into some solutions such as , however the wide range in this application note is only limited to the max of 200uA and in my case, my max current can rise to milliamps when my radio is transmitting and could drop to as low as 3uA when the whole system goes to sleep.


I'm no php programmer, only site admin, I've recently adopted a site with web panel that causes sql injection when trying to post html code in TinyMCE, containing apostrophe.  Problematic html code;  img onmouseover="this.src='layout/gfx/wiecej1.png'   php code;  $edytuj = $_POST['edytuj'];   sql query;  if($edytuj) {      $podstrony_id = $_POST['id'];      $podstrony_id_kategorie = $_POST['id_kategorie'];      $podstrony_id_moduly = $_POST['id_moduly'];      $podstrony_tytul = $_POST['tytul'];      $podstrony_szablon = $_POST['szablon'];      $podstrony_tresc = $_POST['tresc'];      $podstrony_aktywnosc = $_POST['aktywnosc'];       $zapytanie = "UPDATE $tab_podstrony SET id_kategorie='$podstrony_id_kategorie', id_moduly='$podstrony_id_moduly', tytul='$podstrony_tytul', szablon='$podstrony_szablon', tresc='$podstron$      $wynik = mysql_query($zapytanie);   Site uses php-cgi-5.4.39 and mysql-5.5 I don't have access to previous environment (where this panel worked fine), so I can't find out if it's configuration or code problem.

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


Im Iraqi citizen  holding a green card ,living in USA now. I want to visit my relatives in Iraq and stay there for a month. Do I need a visa to re-enter the USA when coming back from Iraq please?!

I am a US citizen but my wife is an Iranian citizen with US permanent resident status, which she obtained through our marriage. We were planning to travel to Iran to visit my in-laws. However, we are worried, , that there will be problems for us and that she will not be able to re-enter the US without a visa.   Will she be able to re-enter the US without having to apply for a visa?  Update: Just wanted to update this question with our experience. We were able to go to Iran and come back without any problems. As the answers to this question pointed out, the green card lets you return and the changes to the Visa Waiver Program has no impact if you are a permanent resident.


The other day I was browsing a German-localized website but needed to order something from their UK site. There was a country selection dropdown so I tried to use that one. I'm not fluent in German so It was hard to figure out that what I was looking for was "Großbritannien". I did look at all countries starting with "U" for UK, "E" for England, "B" for Britain and finally even starting with G but did not easily read Großbritannien as Große Britannien.  My question is, wouldn't it make more sense for this kind of dropdown to show the - or one of the local country names in one of the local languages?  Edit: After posting, I remembered the particular offending website:

Imagine a site that's available in multiple languages. The language is detected automatically by looking at the IP or the browser header. But that's not bulletproof, so a few users might end up on a page in language they don't understand.  I am wondering what the best way is to present the language selection?          – Wireframes created with   Q: Should the languages in the language selection be listed   translated into current language, used to display the site in (good if the detected language was correct)? native name of the language, so everybody looking for their language could see it in the very same language (good if the detected language was not correct and users don't know the current language)? always in English assuming most users would understand this?   Feel free to add if I missed something!


I'm asking if the SE sites or new proposals could have code analysis in its scope similar to , or it's against Stack Exchange rules?  One example of question is , which was closed as off-topic (code analysis), therefore I've created the new  (similar to ) where (malicious) code analysis is on-topic and defining exactly what kind of code it's expected to be analysed.  Is that perfectly fine, fine, worth to try or code analysis is not suitable on SE sites at all?

Is it OK to ask on SO for help in explaining someone else's working piece of code, from Open Source projects or library examples etc.? Or does this belong somewhere else?


I knew that floats float around and sometimes are placed far away from where one wants them to be. With the times I learned to work with it, and there are already many posts about it. I have a kind of different problem. I'm writing my bachelor thesis and defined some environments for definitions and such. And of course I'm using floats as well. But now I have the problem that one of my floats are placed in one of my definitions. This is of course something I really don't want to have. If some of the floats are one page after or before they are referenced, that is ok, but having them in my definitions is no option. I don't know how to create a MWE for this without posting my whole thesis, but this is as close as I can get: \documentclass{article} \usepackage[utf8]{inputenc} \usepackage[english]{babel} \usepackage{blindtext} \usepackage{graphicx}  \newenvironment{myblock}{% \vspace{.5\baselineskip} \hrule\nopagebreak\vspace{.35\baselineskip}\nopagebreak} {\nopagebreak\vspace{.5\baselineskip}\nopagebreak\hrule\vspace{.5 \baselineskip}\noindent}  \newcounter{definition}[section] \renewcommand*\thedefinition{\thesection.\arabic{definition}} \newenvironment{definition}{% \refstepcounter{definition} \begin{myblock} \noindent\textbf{Definition \thedefinition} } {\end{myblock}}  \begin{document} \Blindtext \section{MWE} \begin{definition} \blindtext \end{definition} \begin{figure} \includegraphics[scale=.5]{lorem} \end{figure} \Blindtext \end{document}  This is the picture I used for this example.  Well in this example the picture isn't placed that bad, but in my thesis it is placed inside the definition environment. So my real question is, how can I keep the figure out of that environemnt? PS: If you see any problems with my definition environment that is not related to this question, please let me know. I'm always happy to learn something new.

Given following situation:  \begin{figure}[ht!]     ... \end{figure} \begin{equation}     ...     \end{equation} Some one-line text. \begin{eqnarray}     ...     ... \end{eqnarray}   how can I make sure that the float doesn't get placed between the equation and the equation array? Also the part to protect goes over two pages, if that's of any importance.


I succeed in finding the following limit applying binomials and squeeze theorem: $$\lim(\sqrt{n+1} - \sqrt{n}) = \lim\frac{1}{\sqrt{n+1} + \sqrt{n}} = 0$$ because $0 \leq \frac{1}{\sqrt{n+1} + \sqrt{n}} \leq \frac{1}{\sqrt{n}}$  But I need help because I'm not finding any way to simplify and solve the following limit: $$\lim(\sqrt[3]{1-n^3} + n)$$

I need to find simple limit: $$\lim_{n\to\infty}{\sqrt{n+1}-\sqrt{n}}$$  I can't use L'Hôpital's rule, which I think is natural for such problems. How to calculate such limit using only basic methods (definition and simple transformations etc.)?  It's one problem (from 50 problems) I don't know how to solve from my homework.  Thanks for help.


I  a few months ago. And I can't restore deleted email.  How can I restore or merge my old SO account with the new one?

A while ago I tried to login to stack overflow, but I couldn't remember what email address I used when I registered. Now I've figured it out but the email address is dead, the domain no longer exists. Would it be possible to merge the accounts  and  ?