Isomorphism between multiplicative modulo groups

Group G = {1,2,3,4,5,6} multiplicative modulo 7 Group H = {1,5,7,11,13,17} multiplicative modulo 18  Show the groups are cyclic.  Found a generator 3 of G and 5 of H. How can I check quickly they are generators without computing all powers.  Provide a isomorphic between the groups  Identity goes to identity is obvious what about the rest? I was thinking 3 goes to 5 using (i)?


I have this model structure and want to know the formula for calculating the parameters count in the GRU layer. I did not find that in the docs.   model = Sequential() model.add(layers.GRU(32, input_shape=(None, float_data_1.shape[-1])))  model.add(layers.Dense(1)) model.compile(optimzer=RMSprop(), loss='mae') history = model.fit(train_gen_1,                 steps_per_epoch=per_epoch,                 epochs=20,                 validation_data=val_gen_1,                 validation_steps=val_steps) # model summary  Model: "sequential" _________________________________________________________________ Layer (type)                 Output Shape              Param #    ================================================================= gru (GRU)                    (None, 32)                6336       _________________________________________________________________ dense (Dense)                (None, 1)                 33         ================================================================= Total params: 6,369 Trainable params: 6,369 Non-trainable params: 0 _________________________________________________________________   I found the equation in this  but is does not produce the right results. I would be interested also in the information source as I would need to cite it in an academic report.   the input data shape is (85880, 32)


How can I disable the low disk space warning on a single drive in Windows 8?

Id like to disable the low disk space warning, ideally for a single drive in Windows 8.  My gut feeling is that is it will be an all or nothing change.  Any ideas?


Pluralization rule for "five-year-old children", "20 pound note", "10 mile run"

Why are year, pound and mile in the singular form in the phrases below?   five-year-old children  20 pound note 10 mile run   Is that because they're acting as adjectives, which are always invariable in English?  Is it incorrect to say...   five-years-old children? 20 pounds note? 10 miles run?


Is it faster to compress files before copying?

I have around 80 GB of data I need copy to an external hard drive. Would it be faster to compress all the files first and then copy over? Or would the time it takes to compress and decompress take longer that the amount of copying time it will save?  I'm going to be reinstalling windows so basically documents, pictures, videos etc. And one outlook .pst backup file. And there are 28,284 files.  Also any pointers I should be wary of before I begin that could maybe speed up the process?


Limitation of JavaScript base form validation

Does JavaScript's base form validation have limitations since we know that there is an option for a user to shut off Javascript option from the browser?  Is client side base form validation is an efficient way to validate forms in a web application?


If $|x -4 | + |y - 4| =4$ then how many integers value the sets (x,y) have?

Given  If $|x -4| + |y - 4| =4$ then how many integers value the sets $(x,y)$ have? $x$ and $y$ are both positive and negative numbers.  options a)infinite b)$3$ c)$5$ d)$12$ e)$16$ Solution My Approach: i have just put all the values satisfying the equation Hence, Possible values are $(0,4),(4,0)$ $ (2,6),(6,2)$ $ (1,3),(3,1)$ $ (3,7),(7,3)$ $ (5,7),(7,5)$ $ (8,0),(0,8)$ I am getting wrong ans as the Ans is $16$ Is there any better approach to this problem and why the my ans is wrong.


How can an amateur introduce a cryptographic algorithm?

I have a new cipher, and I want to get it properly vetted, but I don't have a strong way to prove its security properties.  I'm an amateur without ties to a strong cryptographer/university.  I have attempted a few indistinguishability proofs, but these are "back of the napkin" proofs and are likely not rigorous.  (I have colleagues that have done cryptanalysis on it, but they are not theorem types.)  As a result, I feel that I don't stand a chance of getting it published without a proof of security, but I feel that I can't find someone to help without it being published.  How can I find someone willing to join on and help write a compelling proof, and generally help write a compelling paper, (or identify a weakness that prevents me from doing something stupid with the cipher)?  Given that I have done these things:   Review previous ciphers, find they're not what you want, invent new cipher Internally analyze it (plots, prototype code, etc.) Socialize it to cryptanalyst peers, get tentative green light (rather, absence of red light - no new findings in a while)   Is this a reasonable path going forward:    rump session Have follow-on discussions at conference, express my need, find someone that way Submit as a work-in-progress in lower tier, but bonafide crypto conference Submit as a journal article   Is a rump session a good way to go to find interested math types, and/or as a first step to announcing the idea?  Are there other alternatives, such as quarterly meetings of some group that might be willing to hear the idea?  Similarly, is there a good "starter conference" for crypto open to new ideas that might lack the mathematical rigor?  , the main answer suggests that formalisms are a prerequisite to publishing: "If you submit a cipher, one would expect at least a formal analysis of why you think this is a good idea."  My question is what if you don't have that ability - how do you find someone that can help with that?  The rest of the answers on the thread went into how to make it into a bachelor's thesis.    In additional defense of this thread, there are many great suggestions that don't appear on that other post.  While I'm biased - but have nothing to gain - these threads are unique.  I'm okay with marking as duplicate as long as somehow you can merge the useful answers below into the other question.


I've been looking into installing Wine on Ubuntu and the  says that if I have a 64 bit Ubuntu machine I need to carry out a few back flips and install 32 bit Wine. This shouldn't be an issue since there's plenty of material on how to do that but what I'm missing is the why.    provides some clues but unfortunately no sources or concrete cases to look at. I'm looking for some reading material to educate myself a bit on this matter before I decide how and what to do next.  -- EDIT --  This question has been marked as a potential duplicate of . Just by looking at the title of the question you can see that we're asking totally different things. Although the "duplicate" has some relevant info in the various answers that it received, it is a very specific case of someone wanting to force Wine to work in 32 bit and this is entirely not what I'm asking here.  -- END of EDIT --  My two main questions are: A) In what cases do I need a 32 bit installation? Any 64 bit Ubuntu? Only if I want to run 32 bit windows applications? B) If not in all cases then what is the benefit of having 32 (and/or 64?) Wines? Pros? Cons?  Thanks!


, is there an easy and convenient way to install it on Ubuntu 14.04 through the package manager (ie. apt-get)?  I would also appreciate information on how to properly configure my system to use it as its compiler.


I recently reached over 1k rep on a site which means I can see the voting breakdowns for questions and answers which is cool.  However when using the iOS app (and Android I assume) you can't see the voting breakdown (by clicking on current vote score) and you need to go to the full site of a web browser to see the voting scores properly.  I appreciate this isn't mission critical but with it being a feature that requires (that much) rep to attain, I feel it's worth adding to the mobile apps.


What's the equivalent function for mLogit() if random effects are involved?

mLogit is the function for running multinomial logistic regression in R. What if we have random effects (mixed-effects model), what's the adequate function (and package) for this purpose?


I am using sed command make substitution in the file. Assume my file1 is:  10 11 10 11   Then I want to substitute the 1st "10" in file1 to "12", and dump to file2. The file2 should be:  12 11 10 11   I tried this command:  sed 's/10/12/' file1 >file2   But it changed the 2nd "10" also. So, how can I write the sed command to do that?


I am trying to produce the following result:    I've never placed tikz objects on images. Any help would be appreciated.


My reputation graph does not show my accounts

Umm... this was closed as a duplicate to , but, A. That question never got any answers and B. In my particular case, it is showing physical fitness as my account when it is not. It would be helpful if the closers commented with reasoning to help explain why this question was closed. On my reputation graph, the graph is tracking physical fitness SE, even though I don't have an account there. It is not tracking any of my actual sites with 200+ reputation.


LIKE or CHARINDEX to check String Contains a Substring

To check a string contains a sub string or not we can use [LIKE] or  [CHARINDEX]. I know that like uses indexing in case we have name%.(while %name% may not use index) .Also charindex does not use index.  For example I want to get all rows containing employeename as 'av'  select * from employee where CHARINDEX('av', employeename)>0   OR i can do same by using LIKE  select * from employee where employeename LIKE '%av%'   In this case which one is better to use? Charindex or like? Why?


If $X$ is a continuous random variable, then $P(a \le X \le b) = P(a < X \le b) = P(a \le X < b) = P(a < X < b)$. Why?

When introducing the concept of continuous random variables, my textbook states the following:     If $X$ is a continuous random variable, then $P(a \le X \le b) = P(a <  X \le b) = P(a \le X < b) = P(a < X < b)$.   However, it does not give a justification for why this is true.   I would greatly appreciate it if people could please take the time to explain why this is true.


How do I put a count function on my SharePoint list?

How do I see the total amount of items I have in my SharePoint List? preferably on the view screen.


iPhone Whatsapp Lockscreen Notification Problem

Since upgrading Whatsapp to version 2.18.52 contact names do not appear on whatsapp lock screen notifications. For example, if I get a message from Mom, whatsapp only displays the whatsapp logo and “message”, without displaying the sender. I used to be able to see just the contact name (“Mom has sent you a message”), but now, no Names are displayed. This just happened as I updated to ios 11.3.1. Anyone having a similar problem? Please advise how I can fix this issue.   Thank you


Let R is a ring with identity $1$. Show that if $a \in R$ has more than one left-inverse then it has infinite.


Validating a phone number with regex in Android

Having trouble using a regex to validate a phone number.  I want to allow only numbers and hyphens, but so far I've been trying to just get numbers working.  Unfortunately despite different changes after looking around Google and Stack Overflow, the regex continues to evaluate as false.  Ideally, strings such as 8889990000 or 888-999-3333 should both evaluate to true. Any help is appreciated!  Main class code for regex:    boolean correct = PhoneFilter.filterPhone(phone_num);  if (correct == true) {     //create an intent to carry data from main activity to OrderConfirmationActivity     Intent intent = new Intent(MainActivity.this, OrderConfirmationActivity.class);      //pack pizza order data into intent     intent.putExtra("nameSelected", nameEditText.getText().toString());     intent.putExtra("aVariable", type);     intent.putExtra("mtSelected", mt);     intent.putExtra("otSelected", ot);     intent.putExtra("ptSelected", pt);     intent.putExtra("dateSelected", Date);      //start the OrderConfirmationActivity     startActivity(intent);   }         //alert user if phone number entered incorrectly else if (correct == false) {     AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();     alertDialog.setTitle("Alert");     alertDialog.setMessage("Please enter a phone number in either 000-0000-000 format or 0000000000 format");     alertDialog.setButton(AlertDialog.BUTTON_NEUTRAL, "OK",             new DialogInterface.OnClickListener() {                 public void onClick(DialogInterface dialog, int which) {                     dialog.dismiss();                 }             });     alertDialog.show(); }   The code for filterPhone is:    public class PhoneFilter {      public static boolean filterPhone(String phone_text) {         boolean correct;          if ((phone_text.length() <= 12) && (phone_text.matches("[0-9]+")))             correct = true;         else             correct = false;          System.out.println("correct =" + correct);         return correct;          //InputFilter lengthFilter = new InputFilter.LengthFilter(12);     } }


Combine n lists of length y into y lists of length n


Splitting field for $x^4-2\in\mathbb{Q}[x]$.

I am studying the splitting field for $x^4-2\in\mathbb{Q}[x]$. Let $F$ denote the splitting field for $x^4-2\in\mathbb{Q}[x]$. I found that the Galois group of the extension $\mathbb{Q}\subset F$ is  $D_8.$ And since there are four proper normal subgroups of $D_8$ we can conclude that there are four subfields of $F.$ Four subgroups are following: trivial subgroup, $\mathbb{Z}_2$, Klein four group and $\mathbb{Z}_4$.  Now I want to know which of these subfields are stable.  Definition of stable: if $E$ is an intermediate field of the extension $K\subset F$, $E$ is said to be stable (relative to $K$ and $F$) if every $K$-automorphism $\sigma\in Aut_KF$ maps $E$ into itself.  Then by the definition of stable, trivial subgroup and $\mathbb{Z}_2$ are stable? Am I right?


Extract a part of apt repository for offline usage

On the office I have a PC with internet access so I can install packages from the online repositories, but I have a PC at home w/o connection and I want to be able to install packages offline. I wonder if there is a way I can grab a part of the repository for offline usage and transportable on USB drives so I can move this clone from the office to home, I have tried taking my apt-cache from the office to home but doing dpkg -i does not work at home. Grabbing the hole repository with apt-mirror is not a choice due to reduced storage size at home. What choices do I have???


For which primes $p$ is $2^p+1$ divisible by $p$?  What I have been doing is:  $2^p+1\equiv 0\pmod p$  $2^p\equiv -1\pmod p$  Then by Fermat's Theorem, we get  $2^p\equiv 2\pmod p$  This shows $p=1,3$.  I feel like this is not right though...


How to round to 2 decimals in Java with floats

So, assuming, for some reason, floats are absolutely required in the programme one is creating despite the inaccuracy regarding decimal points, is there any method one can use to round them to 2 decimal places without converting them into doubles?


Usage of the article "the" before superlative adverbs

"Tyra sprints best of all competitors."   Is it a correct sentence?


prove that the Dimension for set of all linear mappings $L:V \to W$ is equal to $\dim V \times \dim W$

I wish to prove that the dimension for the set of all linear mappings $L:V \to W$ is equal to $\dim V \times \dim W$. I know that any general linear mapping can be represented as a matrix, so intuitevely it makes sense that the dimension should be $\dim V \times \dim W$ but I cannot find a way to prove this mathematically


I have created java project that contains 6 Class file and 1 java file   And I run this project in net beans IDE now my problem is when I clean and build this project am unable to create exe file   How can I make this project as exe (an executable file)?   all 7 files in one single as executable  and found this and tried from here    Can some one help me to solve my problem


How to add image texture 'layer' onto material?

I'm new to Blender and I have another problem:  I've got myself nice, shiny material on my space ship, however it's really clean and now I want to add some details to it - stripes, logos, text etc.   Basically, I want to make it like it's another layer in Photoshop with different images.   How do I connect these logos textures to my existing nodes?    Node setup:   What I want to achieve:


I get many surfaces when i Unwarp my mesh,(Only two selected)

i'm getting stacked with this issue please help ! it's the first time i use blender i've been modeling for the first time without noticing that i have deferent color faces on my mesh without applying any material or colors !  the mesh looks unified but whene i apply unwarping i get splited surfaces and when i use ambient oclusion it apply only ont this splited face,it's realy strange please help !! here a link to my model for anyone who want to check it !


"Exception in thread "main" java.lang.NullPointerException" error in Rolling Dice Program

I am writing this basic program with 3 classes in 3 separate files. It is supposed to be a program consisting of a class called PairOfDice, composed of two Die objects. Included methods to set and get the individual die values, a method to roll the dice,and a method that returns the current sum of the two die values. A driver class called RollingDice to instantiate and use a PairOfDice object.   It compiles without problems but when I try to run it results in a run-time error as follows:     Exception in thread "main" java.lang.NullPointerException     at   PairOfDice.rollDice(PairOfDice.java:42)   at   RollingDice.main(RollingDice2.java:16)   public class RollingDice {     public static void main(String[] args)     {         PairOfDice pairofdice=new PairOfDice();          pairofdice.rollDice();          System.out.println(pairofdice.getDie1() +"\t" +pairofdice.getDie2());      } }   public class PairOfDice {     private Die die1, die2;      public PairOfDice()     {         Die die1=new Die();         Die die2=new Die();     }      public int getDie1()     {         return die1.getFaceValue();     }      public int getDie2()     {         return die2.getFaceValue();     }      public void setDie1(int dieValue)     {         die1.setFaceValue(dieValue);     }      public void setDie2(int dieValue)     {         die2.setFaceValue(dieValue);     }      public void rollDice()     {         die1.roll();         die2.roll();     }      public int sum()     {         return die1.getFaceValue()+die2.getFaceValue();     } }   public class Die {     private final int MAX = 6;     private int faceValue;      public Die()     {         faceValue = 1;     }      public void roll()     {         faceValue = (int)(Math.random() * MAX) + 1;     }      public void setFaceValue(int value)     {         faceValue = value;     }      public int getFaceValue()      {         return faceValue;     }      public String toString()     {         String result = Integer.toString(faceValue);         return result;     } }


Is there a way to get the date of the first boot of an old mac?

Is it possible to read the date when a mac first booted via terminal or system information GUI? Maybe there's a file set at this moment.


I stumbled over a rather simple result of OLS regression which is  $$ Var[\hat\beta] = \sigma^2(X^TX)^{-1} $$ where $\sigma$ is the variance of the error term $u$ and $X$ is the regressor matrix.  I first just accepted the proof in my textbook but now I am thinking that it either uses sloppy notation or I am missing something. $\hat\beta$ is the estimated and $\beta$ is the true parameter (assuming unbiasedness).  It states that   \begin{align} Var[\hat\beta] &= E[(\hat\beta - \beta)(\hat\beta-\beta)^T] \\                &= E[(X^TX)^{-1}X^Tuu^TX(X^TX)^{-1}]         \\                &=  (X^TX)^{-1}X^T E[uu^T] X(X^TX)^{-1} \end{align}  but $X$ was only assumed to be exogenous and not non-stochastic. Under this assumption I think $X$ cannot be dragged outside the expectation operator.   Momentarily, I think that it should be $Var[\hat\beta|X]$ to make sense. Is that the case? My web research couldn't clarify this. I only found similar derivations to the above without further explainations.


Cross-reference packages: which to use, which conflict?

Inspired by my earlier question , here is another similar question.  There are many different packages for making cross references. Among them , , , , … The  package defines its own cross-referencing command for theorems…  Which collection of packages provides which kind of functionality, and which packages cause conflicts with each other?


How to show all open windows from sample app

I have multiple instances of an app open, e.g. of Terminal. Indicated by the orange dots next to the icon.    Can I configure a shortcut to restore/ show all of those windows with a single click/ command, e.g. double click on the launcher?


I am looking for a way to create custom field from Apex.  Use case: we are using a specific field (E.g.: Own_Id_Field__c, TEXT(255), ExternalID: TRUE).  User should be able to select which (Custom) Object they want to use in the app and this should create custom field (for good functioning).  I would like to do someting like:  public static Schema.DescribeFieldResult createOwnIdField(String sObject) {   // Test if sObject exists   // Create field   return field; }   I heard about using Metadata API but did not really understood.


How do I generate a date series in PostgreSQL?

Let's say that I want to generate a series of dates between two dates.  I see the function  provides only   Function                                    Argument Type                         Return Type                                                               Description generate_series(start, stop, step interval) timestamp or timestamp with time zone setof timestamp or setof timestamp with time zone (same as argument type) Generate a series of values, from start to stop with a step size of step   So how would I go about doing this?


Is there a general term encompassing primary, intermediate, and secondary education?

Is there a general term encompassing the primary, intermediate, and secondary school levels? Perhaps pre-university or pre-college, maybe even prep school. However, the last of these, as I saw on , refers rather to private and parochial schools. I would like to use it as an adjective.


I just downloaded a Ubuntu ISO today and wanted to see what time the file was downloaded. I tried viewing the file "properties" feature to see if it would tell me it. The file size, what directory it was saved in, etc. was displayed along with some times in military time format with the following lines:  Accessed: Wed, Oct 18 2017 14:29:30  Modified: Wed, Oct 18 2017 14:29:29  Are one of theses possibly the time I downloaded it? Is so, why are the two different because one is a second behind. I do not remember ever modifying the file what so ever. Thanks!


Im trying to run a simple cloth simulation in 2.83 but the result is like scrutched up and looks terrible, also it takes like 15 minutes to bake 60 frames. I don't know if it's because of the sewing force or self collision. If anyone can help me, I'd be grateful!


I have been having an overheating issue which makes my laptop shutdown immediately. Is there anyway to monitor the temperature from the sensor and scale down the CPU frequency to avoid that problem? Is there any existing software or shell script that can handle that job?


one to one onto and composition functions

I'm kind of confused about how to prove one to one and onto with functions and composition functions. I am also a visual learner. Could someone tell me step by step how to prove whether or not a function is one to one and if it is onto? Help is greatly appreciated!


Enumerating all available drive letters in Windows

I want to enumerate all available drive letters (which aren't already taken) in Windows using VC++.  How can I do this?


so im working with a MMORPG Map editor at the moment, and having trouble loading my cache, and, to be honest, trouble loading the editing software itself.  Now i believe im reasonably close, as ive been using tutorials on stackoverflow to help with the problems ive found(thank you stackoverflow) but ive come to a complete halt caused by an import error which has thrown a bigger error(this is the general error eclipse is giving me):  Badseek - pos:70502120 len:112014898 SOMESHITWRONGWITHNEXTFILEtrue true true Dec 07, 2015 7:35:34 PM com.jme3.app.Application handleError SEVERE: Uncaught exception thrown in Thread[LWJGL Renderer Thread,5,main] java.lang.NullPointerException at com.runescape.net.Buffer.get24BitInt(Buffer.java:152) at com.runescape.cache.Archive.<init>(Archive.java:28) at org.fabian.rsmt.RSMapTool.getArchive(RSMapTool.java:74) at org.fabian.rsmt.RSMapTool.loadCache(RSMapTool.java:296) at org.fabian.rsmt.RSMapTool.simpleInitApp(RSMapTool.java:125) at com.jme3.app.SimpleApplication.initialize(SimpleApplication.java:226) at com.jme3.system.lwjgl.LwjglAbstractDisplay.initInThread(LwjglAbstractDisplay.java:130) at com.jme3.system.lwjgl.LwjglAbstractDisplay.run(LwjglAbstractDisplay.java:209) at java.lang.Thread.run(Unknown Source)   so when i follow the links, the only thing they all have in common is the imports my source file is using (RSMapTool.java)  This element has no attached Javadoc and the Javadoc could not be found in the attached source.  Now based off that error, im not 100% if my imports are causing in, and if not, then in that case ive got an even bigger error im gonna need help with o.O, but if it is the imports, and someone can make enough sense out of my details provided to give me a run-down on how it should be, that would be great  Things i have tried:  I attached the imports to their respected sources, and figured out how to build a javadoc path(if thats correct) and validated said path, but still got both errors.


Showing $2\int_{-\infty}^{\infty} x f(x) F(x) \ dx = \frac{1}{\sqrt{\pi}}$ for standard normal pdf and cfd

i am trying to prove the identity in the title. I strongly think I need to use the error function $$\text{erf}(x) = \frac{2}{\sqrt{\pi}} \int_0^x \exp\{-t^2\}\ dt$$ in some way. Best I have so far is replacing $F(x) = \frac{1+\text{erf}\left(\frac{x}{\sqrt{2}}\right)}{2}$ to end up with  $$2\int_{-\infty}^{\infty} x \, f(x) \, F(x) \ dx = \int_{-\infty}^{\infty} \text{erf}\left(\frac{x}{\sqrt{2}}\right) \, x\, \frac{1}{\sqrt{2\pi}} \exp\left\{-\frac{1}{2}x^2\right\}\ dx.$$ My attempts on partial integration have failed, any other ideas or does anyone succeed?  I have a document stating that the equality holds without any further remarks or calculations and I have confirmed it via integration by quadrature and am looking for an analytic proof.  Very thankful for any help.


To evaluate limit of sequence $\left(\left( 1 + \frac1n \right) \left( 1 + \frac2n \right)\cdots\left( 1 + \frac nn \right) \right)^{1/n}$

How do I evaluate the limit of the following sequence $$a_n  = \left(\left( 1 + \frac1n \right) \left( 1 + \frac2n \right)\cdots\left( 1 + \frac nn \right) \right)^{1/n}$$   I tried to take log and then using cauchy $1^{st}$ theorem of limits but I coudn't do it.  Could someone kindly help?


Some characters are showing as "?" in libreoffice impress

Some symbols in equations in a presentation show up looking like this in LibreOffice      I'm using Ubuntu 16.04.1


As you know there are two forms of lowercase letter A: 'a' and 'ɑ'. I am writing a linguistics article and use IPA where the two characters denote different things. There are cases where I want to type an italic 'a' but the italic form of this letter (at least in my Latex) looks like an italic 'ɑ'. Is there a way type a proper italic 'a'? I'm using Xelatex (I'm willing to switch if necessary). Is there maybe a font that can handle the issue?


It is possible -- indeed, quite easy -- to rotate JPEG-files without re-encoding them, which means, no additional loss of quality is introduced in the process.  Is the same possible for the similarly-lossy video-formats (MPG, MP4)?


What would be the proof for $\langle q| p \rangle = e^{ipq}$?  Is it derived from canonical commutation relation?  ($|q \rangle $ represents the position eigenstate, while $|p \rangle$ represents the momentum eigenstate.)


Java MultiThreads UnitTest does not notice change in class

I'm completely new into MultiThreading and I'm trying to test code in which there is thread.sleep, long story short it looks like this:  private class DemoRunnable implements Runnable {      private Thread t;      String status;      public void start() {         this.status = "RUN";         if (t == null)             t = new Thread(this);         t.start();     }      public void run() {         int i = 0;         while (i < 8) {             i = i + 1;             try {                 System.out.println("GO  " + i);                 Thread.sleep(300);             } catch (Exception e) {                 e.printStackTrace();             }         }          this.status = "FINISH";         System.out.println("inside " + this.status);     }      String getStatus() {         return this.status;     } }  class DemoTest {      @Test     void test() {          DemoRunnable demo = new DemoRunnable();         demo.start();          while (demo.getStatus() != "FINISH") {          }     } }   Of course it's only the draft - I cut it short to make it more clear, but kept the same concept. At first I tried to test it without the while loop but junit test would finish before the Thread and only one GO would be printed out. After adding the loop everything looks fine GO is printed out correctly and then the status is changed but the test goes on forever :< Like if it was not noticing the status change.   when I remove sleeping then test does notice the change in status and while loop is broken


Is there any way to get notified when battery is full?

I'm using Ubuntu 12.04 on a laptop, I was wondering if there is a way to get notified when the battery become full.


How to use GROUP BY to concatenate strings in SQL Server?

How do I get:  id       Name       Value 1          A          4 1          B          8 2          C          9   to  id          Column 1          A:4, B:8 2          C:9


are graphs with fractal dimensions possible?

As I am new to understanding fractals, I appreciate their beauty when graphed in cartesian coordinates. My intuitive understanding of the definition of a 'fractal dimension' is the relation of the length of a fractal segment as a proportion of the subdivisions used in making it. In this way. the cartesian 2D coordinate system is calculated to have dimension 2. When we therefore create 2 axes, we can plot a set of points each of which has a real number value in each of these dimensions.  But I imagined a coordinate system not of 2 dimensions, but for example of the dimension of a Koch snowflake, 1.26186. But what does it mean for there to be 1.26186 coordinates for a point? Is this a concept that has been addressed in mathematics? Please do not be hasty to condemn this question as stupid- the concept of the square root of negative one seems equally absurd to me. Yet mathematicians invented a way to deal with that question. And the result was a tool that was miraculous-enabling Fourier transforms and a host of other useful tools-that still want to make my brain explode.  Certainly the concept of length in the fractal dimension has been addressed    So if there is length, then is there not a way to map the fractal coordinate system into the cartesian one so i can visualize it? or would the result be so mind boogling as to exceed comprehensibility- like those drawings of hypercubes in 3 space? We map all the aspects of a hypercube into different 3D cubes and either throw them into a 3D picture together (very messy) or we make a movie of transitioning from one cube to another through time.(very trippy)


Will forcing response time to the average time as a minimum improve UX?

I have a situation where my Ajax call response time could vary from 14ms to 600ms, because of the complexity of a Query they could make.  From my experience Users take for granted those 20-80 ms round trips and expect to have the same speed all the time and everywhere, in reality in my particular project it is impossible.  So I came up with an idea that I could force users always wait for at least some x amount of time before getting results.  Question is: Should I use an average of my own data of response round trip lengths already gathered or should I just use a publicly agreed highest allowed response time to a  Users action?  From what I can remember that was somewhere between 100 - 200 ms I can't remember now.


What would happen if I were to fall into a massive hollow planet?

Imagine, if you will, there exists somewhere out there a supermassive planet. For some reason, this planet is only a shell of its former existence and all that is left is a crust of substantial size to keep it from collapsing in on itself (let's imagine it is stable at 5000' thick). Now, this planet was HUGE! How large, you ask? Large enough that the remaining shell is still able to maintain a gravity well strong enough to keep you anchored to the surface.  Pretty neat, huh?  Well, since this is a sight to be seen by everyone, you stroll along and, not looking where you are going, you tumble into a chasm and straight down into a hole that permeates the thickness of the shell. As you are falling down and down and down, you think:  "At what point do I stop falling down and I start falling up? And would I be able to retain the velocity, since gravity is a conservative force, and fall back through another hole on the surface on the opposite side? Where would the center of gravity even exist? I mean, aaaaahhhhhhh!"  What say you, browsers and scientists? A stretch of the imagination, sure, but is it physically possible? Could there exists a configuration similar to this where gravity could be concentrated to a point but still allow free travel up to the focus?


State Space model identification with Kalman Filter

If I have a standard state-space model where all parameters are unknown (coefficients and covariance matrices for both the state equation and observation equation) and I want to estimate it with the kalman filter. Is it possible to estimate all the parameters at once? Is there a minimum number of observed variables that I need?  For example, if I have a state vector with 20 variables, seems unreasonable to me that I could identify all these parameters with only 1 observed variable. What is the formality around the dimension of the system that can be estimated?


19.10: boot frozen on "/dev/sda2: clean, x/x files, x/x blocks"

Ubuntu 19.10 boot frozen on "/dev/sda2: clean, x/x files, x/x blocks"  On boot my laptop freezes at the message in the title (with x as some number). I can access the command line with Ctrl+Alt+F1...F6  Prior to this, I had uninstalled python with: sudo apt remove python python3 python 3.8  I reinstalled all those packages with:  sudo apt install python python3 python3.8  once this error occurred, but it still persisted.   With Ctrl+Alt+F1, I can login to a screen with this message:     debugfs: File 'Codec' in directory 'System PCM' already present!   Would really appreciate help with this!


I need to load data from Postgres to Oracle. While reading data from Postgres I got the date in below format "2013-02-13 00:30:22.402" now I need to load this date into oracle db  I tried but getting exception   String dd = "2013-02-13 00:30:22.402"; DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS"); java.sql.Date dateform=(Date) formatter.parse(dd); System.out.println(dateform);   Throws this exception:  Exception in thread "main" java.lang.ClassCastException: java.util.Date cannot be cast to java.sql.Date     at ghg.main(ghg.java:26)


Is there a way to configure pdflatex to make all but the .tex and .pdf files hidden files?

I have asked a  about how to manage all the files generated when my LaTeX files are compiled but the approach in the answer I accepted is still unsatisfactory for the many small documents I generate.    I realize the LaTeX  all the files it generates so I can't prevent their creation.    However is there a way to configure pdflatex to make all but the .tex and .pdf files hidden files (i.e., preceded by .)?   (Edit: The two main systems that I use are tex live on Ubuntu Linux and BasicTeX on OS X)


Singular or plural verb with a list of three items

I have seen the following sentence in a published book:  Sentence A There were a toothbrush, a piece of floss, and a tube of toothpaste.  It sounds wrong to my ear. I would write  Sentence B There was a toothbrush, a piece of floss, and a tube of toothpaste.  This is because I believe the verb should agree with the nearest noun, i.e., "a toothbrush".  Is the original sentence correct, or are both versions correct? Many thanks


A practical way to check if a matrix is positive-definite

Let $A$ be a symmetric $n\times n$ matrix.  I found :     $A$ is positive-definite if  all the diagonal entries are positive, and   each diagonal entry is greater than the sum of the absolute values of all other entries in the corresponding row/column.   I couldn't find a proof for this statement. I also couldn't find a reference in my linear algebra books.  I've a few questions.   How do we prove the above statement? Is the following slightly weaker statement true?       A symmetric matrix $A$ is positive-definite if all the diagonal entries are positive, each diagonal entry is greater than or equal to the sum of the absolute values of all other entries in the corresponding row/column, and there exists one diagonal entry which is strictly greater than the sum of the absolute values of all other entries in the corresponding row/column.


Dual UK/Australian citizen... entry to UK with Australian passport only?

Can I re enter into the United Kingdom on my Australian Passport (with a photocopy of my british passport) ??   I am travelling to the USA and need to leave my UK passport here to get a visa sorted out to Russia, can I get back in with out my UK Passport with out any problems?


Every Riemann integrable function is almost equal to a bounded Lebesgue integrable function.

Let  $f  : [a, b] \to \mathbb{R}$ is a Riemann integrable function. Then is it true that there always exists a bounded Lebesgue integrable function  $g : [a, b] \to \mathbb{R}$ such that $g$ and $f$  are almost equal but $g$ is not Riemann integrable. If it is true than how to prove and if it is false then can we find a counterexample. I know that the zero function is almost equal to the Dirichlet function which is not Riemann integrable but is Lebesgue integrable. Thus the question that comes to my mind is that is it true for any Riemann integrable function. .


I am trying to list all the files from dir1, dir2, dir3 and dir4 which might be anywhere in as a sub directory of my cwd using the find command. I tried the following with no success:  find . -type f -regextype posix-egrep -regex 'dir1/.+|dir2/.+|dir3/.+|dir4/.+'   I tried posix-extended as well. How can I list these files?


Why do the braces in f{\left(x\right)} affect the output?

Why does f\left(x\right) result in more space before the ( than f{\left(x\right)}?  i.e. Why does putting extra braces suppress the space?


$R = \mathbb{Z}[i]\ /\ (1+3i)$ - Ring homomorphisms

Let $R = \mathbb{Z}[i]\ /\ (1+3i)$ (a) Conclude that R is a ring and $|R|=10$. (b) Define $\phi:\mathbb{Z} \rightarrow R$ by $\phi(n) = 1_R + \ldots + 1_R$ ($n$ times) if $n>0$ and $\phi(-n) = -\phi(n)$. Show this is a ring homomorphism. (c) Show that $\mathbb{Z}/10\mathbb{Z} \cong  \mathbb{Z}[i]\ /\ (1+3i)$  (a) I think I need to use $(1+3i)(1-3i)=10$ but not sure how. (b) I'm not sure how to show this. (c) Maybe I need to use the kernel but I'm not sure how to start.


Let $G$ be a group of order $p^2$. Use the class equation to prove that $G$ is abelian.   The conjugacy class equation, at least how I remember it, is $$ |G| = |Z(G)|+\sum_{x\in I \backslash Z(g)} \frac{|C|}{C_G(x)} $$ where $|Z(G)|$ is the center of $G$, and $|C_G(x)|$ is the central subgroup of $G$.  I am tempted to start with using Lagrange's theorem, which gives possible orders $o(x,y)$ of $1,p,p^2$.    Now, to prove that $G$ is abelian, perhaps I need to prove that $|C_G(x)|=G$? ($C_G(x)$ being the central subgroup in which every element inside of it commutes)


I have the following design. Each user has it's own contacts, it's own hosts and assign those to a domain which belongs only to him.   I want to insure that the host you assign to the domain belongs to the user that domain is assigned to.  Is it something that I have to insure in my application logic?  If I set domains.user_id foreign key to reference host.user_id and user_id.id does it eliminate my issue?    By the way can anyone suggest me a better design for my schema?


Prove that any odd number can be a leg in a Pythagorean Triple

$(a,b,c)$ where $a^2+b^2=c^2$ is a Pythagorean triple.  My first thought was to do a proof by cases. I have three cases :   a is odd, b is odd. a is odd, b is even. a is even, b is odd.   I'll just show case one :  $(2k+1)^2 + (2k)^2 = c^2$  I am kind of stuck relating how this answers the question. Thank you for any guidance in the right direction.


Combinations of selecting $n$ objects with $k$ different types

Suppose that I am buying cakes for a party. There are $k$ different types and I intend to buy a total of $n$ cakes. How many different combinations of cakes could I possibly bring to the party?


My auto update of Clam Defs doesn't seem to be working and when I do  sudo freshclam   I get  ERROR: /var/log/clamav/freshclam.log is locked by another process ERROR: Problem with internal logger (UpdateLogFile = /var/log/clamav/freshclam.log).   I've tried reinstalling Clam.. Same problem.  How can I solve it?  I tried the command from the linked question   $ sudo lsof /var/log/clamav/freshclam.log  lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs       Output information may be incomplete. COMMAND     PID   USER   FD   TYPE DEVICE SIZE/OFF     NODE NAME freshclam 21238 clamav    3wW  REG  253,1     3587 29757231 /var/log/clamav/freshclam.log   This seems wrong? Should I be worried? And how should I proceed?


Do D&D 5E characters get the characteristics of both Classes AND Backgrounds?

I went into character creation assuming yes, but I feel like I'm overdoing it. If I'm doing this right, my Half-Elf Cleric (Nature) with Acolyte Background has:   Two Holy Symbols (from Cleric and Acolyte) Proficiency in seven skills. Fluency in five languages.   I'm just going with my gut here, but something doesn't feel right. When I designed a Tiefling Warlock a while back, I only had two languages and 4 skill proficiencies.  Am I doing something wrong?


How can I pass aliases from a shell to a script run by it?

$ alias alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"' alias egrep='egrep --color=auto' alias fgrep='fgrep --color=auto' alias grep='grep --color=auto' alias l='ls -CF' alias la='ls -A' alias ll='ls -alF' alias ls='ls --color=auto'   I was wondering how I can pass the aliases from the shell to a script? Thanks.  $ cat myscript  #!/bin/bash alias  $ ./myscript  $


Specifying a preprint is "submitted", *to a specific journal*

There are some mathematicians who are active online and who blog about their work at various stages, including when they upload a paper to the arXiv. I like this aspect as it gives a chance for the author to give a more informal explanation as to how the results were arrived at or how to interpret them. However, I've seen a few times they they say, on their blog or in the arXiv comments, that the paper is submitted for publication (which is perfectly fine), but additionally specify exactly which journal it has gone to.   As these mathematicians are in fact well-respected and solid in their career I do not wish to impugn their decision, but it smacks of me of being rather confident that the journal will accept the paper, after some small revisions. Since the refereeing process in mathematics takes months, at a minimum, and up to a couple of years in more involved cases, the statement that the submission is to a particular journal will stand for a long time before we know either way as to the result.  As a early career researcher I wouldn't presume to proclaim the journal I think my work should be published in. But am I selling myself short? Let us say I am reasonably confident the paper I am submitting is a good fit for the chosen journal, should I also stake my claim during the preprint phase, to signal at least how "good" I think my paper is? (which judgement people can then assess based on their own experience)  Edit: I see the answers at the previous similar question, while acknowledging the practice to be field-dependent generally warn against this behaviour. However I am observing a career-stage-dependent behaviour in my field contrary to those good suggestions, weighted towards those who already have some advantage (to borrow from Dan Romik's example, imagine Bob could always carry through on his promise, never overstepping the bound on what had actually been done).


Is there a name for the practice of dropping pronouns in written speech?

I’m specifically thinking about emails I receive all day where someone will write:     Haven’t seen it yet.  Will respond when received.   If it were spoken, we would certainly hear:     I haven’t seen it yet.  I will respond when I receive it.   It’s mostly the dropping of I that I wonder about.  Is there a name for this phenomenon?


Hey there I am new to Ubuntu and I was working on to change the size of weird large-looking apps in the applications menu. Is there any way to do so? I am using Ubuntu 20.04.


I've a problem in using NULL with NOT in sub-query, the code is:   Create table #FirstTable(i int) Create table #secondTable(i int) insert into #FirstTable(i) values (1),(2),(3),(4),(5) insert into #secondTable(i) values (2),(3),(null)  select * from #FirstTable where i not in (select i from secondTable);   The expected result would be 1,4,5 but it gives null, how can I get the expected value? The question is somehow similar to the referred question but specifically that question is including joints with different values


Creating a host record for an IP address to be used for SPF

I would like to allow an email service to be a valid sender for my domain. This service has dedicated a single IP for my account.   Instead of:  v=spf1 ip4:1.2.3.4 -all   Will the following behave the same assuming I have a host record corresponding to the IP address?  v=spf1 include:service.domain.com -all   *edited to correct -all syntax


Sequence equation. Looking for a value at n = infinity. Basic stuff.

I don't know how to do sigma equations, but my question is:  1/1 + 1/2 + 1/3 + 1/4 + 1/5.. .. + 1/infinity = ?  can this be calculated? is the answer infinity or does it stop at a value?  I tried to create the sequence in c# (very simple program).          double x = 0;         double n = 1;         while (true)         {             x = x + 1 / n;             Console.WriteLine(x);             i++;         }   cmd is capable of calculating 10k sequences per second. I can see that the value is slowing down. At stage 10.000.000 the value is about 16,7.  How much is the value at n=infinity?


Setting up multiple Windows 10 PCs using a single image

I have 12 brand new computers that I am configuring for a client. Instead of setting them all up one at a time I want to configure one PC, create an image and mount that image across the rest of my PCs. I have done this successfully for all the PCs but now I am wondering if this is going to cause problems. Here are the concerns I have.   Will this cause all of the PCs to use the same Windows 10 Product Key which will violate the licensing agreement? Under "Device Specifications" in the "About" section of "System Settings", the "Device ID" and "Product ID" are now identical across all 12 PCs. What are those two values used for? Will this cause problems having 12 PCs on the same network with these two values duplicated?   In an attempt to work around this issues, I decided to test a disc Clone rather than just using my backup image. So I reset one of the PCs back to the factory original settings and cloned the disc from my "model" machine. After performing the clone I can confirm the same experience was seen. The Device ID and Product ID was now again duplicated on the destination machine.  I am using Acronis True Image 2019 for image and cloning, and the new PCs are Lenovo P330s.


I'm a copy editor at a law firm and need to give a quick-and-dirty explanation of the difference between "sell" and "sale" to a native English speaker (a legal secretary) who is very self-conscious about her grammar knowledge. I've already given her info about how they are different parts of speech, and some example sentences. She's still not comfortable with her understanding but doesn't know or isn't able to articulate the area(s) of difficulty. Any suggestions?


What is the fallout of unarmed strikes no longer being weapons?

In the latest errata for the D&D 5.0 PHB, unarmed strikes apparently ceased to count as weapons, being something you use instead of weapons:  Equipment Weapons (p. 149). Unarmed strike doesn't belong on the weapon table. Combat Melee Attacks (p. 195). The rule on unarmed strikes should read as follows: "Instead of using a weapon to make a melee weapon attack, you can use an unarmed strike: a punch, kick, head-butt, or similar forceful blow (none of which count as weapons). On a hit, an unarmed strike deals bludgeoning damage equal to 1 + your Strength modifier. You are proficient with your unarmed strikes."  Is this a significant change, or just a relatively benign clarification or error-fix, particularly with regards to how it affects Barbarians, Monks, and Brawlers? Is this a major nerf or empowerment in any way, and if so why? How much does this actually affect characters who fight unarmed — does it break or change a lot, or only a limited obscure amount? Does this break popular character builds? (Is it doing enough I should be letting my players reroll?) If it's hard to tell how much this affects, I'd be interested to know that as well.


solving diophantine equations using congruences

So, a question in Elementary Number Theory by David M. Burton:     Problems 4.4      2(a) Using congruences, solve the diophantine equation 4x + 51y = 9       Hint: $4x \equiv 9(mod \ 51) $ gives $ x = 15 +51t$, whereas $ \ 51y \equiv 9 (mod \ 4)$ gives $y = 3+4s $. Find the relation between $s$ and $t$ From this hint, I substitute $ x = 15 +51t$ and $y = 3+4s$ in the given equation $4x + 51y = 9$ to get the relation $s = -t-1$ and using which I can get the solutions $ x = 15 + 51t, \ y =-1-4t$ But we know that the solutions of $ax \equiv b (mod \ n)$ is equivatent to the solutions of the diophantine equation $ax -ny = b$, so, solutions of $4x \equiv 9(mod \ 51) $ is equivalent to solutions of the equation $4x-51y=9$ whereas, solutions of $51y \equiv 9(mod \ 4) $ is equivalent to solutions of the equation $-4x+51y=9$ Now, my question is: as, the above equations $4x-51y=9$ and $-4x+51y=9$ are different, then what is the point of substituting $ x = 15 +51t$ (solution of $4x-51y=9$) and $y = 3+4s $ (solution of $-4x+51y=9$) in the given equation $4x+51y=9$ to find a relation between $t$ and $s$ ? Isn't it absurd as $ x = 15 +51t$ and $y = 3+4s $ are solutions of two different equations? Can anyone please explain this? PS: I did it like this $4x \equiv 9(mod \ 51) $ gives $ x = 15 +51t$ and by substituting it in $4x+51y=9$ we get $y=-1-4t$


Stack Overflow has successfully borrowed at least one XBox feature (Achievements).  I'd like to see another feature borrowed as well. Let's say I'm playing Halo online and another player is being a bigot.  I have the option to add him to a list of ignored users.  After doing that, all the racist things he says will never be heard through my headphones anymore. Now, on Stack Overflow, I'd like the ability to add a user to a list of ignored users.  This would hide all of that user's comments, and maybe his questions and answers as well (not sure if hiding questions/answers is necessary). This serves multiple purposes:  It would make it easy for users to avoid other users' flamebait. It would give users a more appropriate response to flamebait. The ability to start flame wars would be reduced, since fewer users would see those comments. Users would now have an incentive to be more diplomatic, as there is now a negative consequence to the behavior (the silent treatment). Administrators could review which users are the most often ignored, which would be a strong indication that someone should be  or even locked out of their account. Administrators wouldn't have to spend as much time dealing with complaints about abusive users, since users would have a better way to respond.    makes a good point in a comment to an answer, that I thought should get more visibility:  I had a problem, reported it and got the response "not bad enough to do anything about, sorry". Which is kind of true, because the only options available to the mods are the nuclear one (penalty box) and the zero-effect one (do nothing). We need a middle ground option where abuse can be handled for you without also being handled for everyone.


Abstract, Interface, Classes OH MY - Question on Approach

So I believe that I have a real world use case for an object model that uses abstract classes and interface. I do however have a few questions about the best way to go about it:  Interface  public interface iLove{    String pet(); }   Abstract  public abstract class Animal{    public string animalName {get;set;}    public boolean happy {get;set;}     public virtual boolean isHappy(); }   Class  public class cat extends Animal implements iLove{    public cat(String nm){      animalName = nm;   }    public string pet(){     system.debug(animalName);             happy = true;     return 'prrrrrrr';   }    public override boolean isHappy(){     return happy == null ? false : happy;   }  }   So, if I instantiate like this:  Animal a = New Cat('Fred');   I do not have access to the method pet() since Animal does not implement pet  Doing this:  iLove i = (iLove)a;   I can now can execute pet()  However, if I instantiate like so:  iLove i = New cat('Fred');   Executing pet() debugs the animalName and there is no access to isHappy() or animalName directly  Now, the goal is to have many Animals that have a common definition (Animal) that may have different interfaces. for this example each one implements their own pet method, Dog - Bark, Lion - Roar, etc.  Is there a better way to handle all of this where I would not have to Instantiate Animal and then cast to iLove  Goal would be one line for instantiation where I would have access to the properties in Animal as well as the methods of the interface without having to do  Cat c = New Cat('Fred');   As obviously that would work but then it cuts out the whole point of the interface....  Is the casting of the SuperClass to the Interface the way to go about it?  Should I just define the abstract methods in the abstract class. If so what is the point of the Interface. I would suspect in this case it may not be needed but could be used if other classes which to interact with the cat without having to worry about the Animal class.  Thoughts?  Putting the interface on the Animal class has similar effects...


How do I prove that $\sum_{\ell\text{ odd}}^{n} \binom{n}{\ell} = 2^{n-1}$?

I'm trying to prove the statement $$ \sum_{\ell\text{ odd}}^{n} \binom{n}{\ell} = 2^{n-1} $$ by induction. The base case is $$\sum_{\ell\text{ odd}}^{1} \binom{n}{\ell} = \binom{1}{1} = 2^{1-1} = 1.$$ For the induction step, I'm assuming that $$\sum_{\ell\text{ odd}}^{n} \binom{n}{\ell} = 2^{n-1}$$ and trying to prove $$\sum_{\ell\text{ odd}}^{n+1} \binom{n+1}{\ell} = 2^{n+1-1} = 2^{n}$$ Because $$ \binom{n+1}{k} = \binom{n}{k} + \binom{n}{k-1}$$ $$\sum_{\ell\text{ odd}}^{n+1} \binom{n+1}{\ell} = \sum_{\ell\text{ odd}}^{n+1} \binom{n}{\ell} + \sum_{\ell\text{ odd}}^{n+1} \binom{n}{\ell-1}.$$ The first part of the expression is equal to $$2^{n-1}$$ so I'm just trying to prove that $$\sum_{\ell\text{ odd}}^{n+1} \binom{n}{\ell-1} = \binom{n}{0} + \binom{n}{2} + \dotsb = 2^{n-1}$$ but I'm stuck at this step.


Suppose $x^2=1$ for all $x \in G$. Prove that $G$ is abelian.

Suppose that $G$ is a group s.t. $x^2=1$ for all $x \in G$. Prove that $G$ is abelian.    If we assume that $x^2 = 1$ for all $ x \in G$, and suppose that $a,b \in G$ and if $x=ab$ we see that $x^2 = abab =aabb = a^2 b^2$. Simplifying we see that $ab=ba$, and because we know that $x= ab$, we see that $1=1$. Therefore it is abelian. $\square$  Is this sound? I'm struggling with this stuff because I think it's so simple and I'm concerned I'm overthinking it.  I'd like to contest the mods decision that this is an exact duplicate. Though there are similar questions, as has been linked, it is not the same thing. If it is a problem with the abstract algebra tag, then delete it and allow it to be an active thread under other tags.


If we have some prime $p$ and a natural number $k$, is there a formula for the largest natural number $n_k$ such that $p^{n_k} | k!$.  This came up while doing an unrelated homework problem, but it is not itself homework. I haven't had any good ideas yet worth putting here.  The motivation came from trying to figure out what power of a prime you can factor out of a binomial coefficient.  Like $\binom{p^m}{k}$.


I have a mdb file (inventory.mdb) with different empty tables (store1, store2, ...) and I have hunderd csv data. I should read and save the csv files into LinkedList and write them in different tables in mdb file. I import and save the csv with this method: (storedata is a linked list) private void loadTxtForStores(String path) {     try (BufferedReader br = new BufferedReader(new FileReader(path));)     {                  String line = br.readLine();         while (line != null) {             storedata.add(line.split(";"));             line = br.readLine();            }              }          catch (IOException ioe)      {         ioe.printStackTrace();     } }  But I have no idea how can I write them into the mdb. I think this is possible with a proprate library.


Could traffic acceleration/deceleration change the rotation of Earth?

For example at a stop light where multiple cars and trucks are accelerating at the same time all the torque from all the vehicles.


How does Temperature influences the rate of protein turnover?

Question  How (quantitatively speaking) does temperature influences rate of turnover of transcription factors?  Which protein?  As I am not looking for any accurate number I am talking about an "average" transcription factor. I leave to you the choice of answering this question with some very accurate example (Transcription factor GTF II A for example) or with some broad observation on how temperature influences protein turnover.  The organism I'd like to model is a typical unicellular eukaryote such as a yeast for example that lives at "standard" range of temperature (between 5°C and 35°C roughly speaking).  Of course, I am not interested in considering a transcription factor that is directly involved in some response to a change in environmental temperature. I am interested in transcription factors which are involved in developmental pathways that have nothing to do with reaction of the body to temperature.  I am looking for a referenced answer $\ddot \smile$


The Universal Translator and similar machines: any armwaving argument as to how a universal translator might work?

Everybody on this site must be familiar with the Universal Translator of Star Trek.  I do not recall any explanation, even a vague one, of how it worked, and worked (almost?) instantaneously at that.  In contrast, FTL travel has at least one arm-waving justification in the wormhole (although this does not apply to FTL travel in Star Trek.)      My question is: Is there an argument used in SF as to how a UT might work -- beyond just it reads one's mind?


I know that in a compact Hausdorff space the quasi-components of the points coincide with their connected components, but I'd like to know if the Hausdorff hypothesis is needed.   I could not find a counterexample, i.e. a compact space in which a connected component is strictly contained in a quasi-component. I tried with the finite-complement topology, but it is connected. So it cannot be a counterexample because such a space must have infinite connected components.  So my question is: is there such a counterexample?  P.S. Sorry for my bad English, but I'm Italian and don't speak English very well.


Is it possible to interconnect 2 PC with Thunderbolt 3?

As Thunderbolt 3 incorporates controller and has 40Gbits bandwidth, I believe it should be possible to link two PC with in a network.  I have an Intel NUC/Linux.


When python creates new objects in memory

In the following example Python uses the same integer object in the memory for all three names x, y and z in the namespace  def main():     x = 0     y = 0     z = 0     print(x,y,z)     print(x is y is z)     y = 2     print(x,y,z)     print(x is y)     print(z is y)     print(x is z)  if __name__ == "__main__":main()   Output:  0 0 0 True 0 2 0 False False True   Why Python doesn't use the same tuple object here ( yes it is the choice of language designers but why) and a better questin to ask is when python creates new objects in memory  def main():     a = 1, 2, 3     b = (1, 2, 3)     c = 1, 2, 3      print(type(a) == type(b))     print(a == b)     print(a is b)     print(a == c)     print(a is c)  if __name__ == "__main__":main()   Output:  True True False True False


I am coding a little election Program for the upcoming Election's in Germany. Well, it is not working.   public static void main(String[] args) {     String _Kandidat1;     String _Kandidat2;      _Kandidat1 = JOptionPane.showInputDialog("Do you Vote for the AFD or for the CDU ?");     if (_Kandidat1 == "AFD")         System.out.println("The AFD won the election!");     else         System.out.println("The CDU won the election!");     } }   If I type in "AFD" it says the CDU won. If I type in "CDU" in nothing happens. I'm not sure, but I think the mistake is in if (_Kandidat1 == "AFD")   Any solutions?


I get an error in my program saying "Unresolved External symbol", i tried everything i know but couldn't solve it. I started getting this error after i used class template.  Here is FileHandler Class Header :-  #include <string> #include <iostream> #include "test.h" #include <iomanip> #include "Administrator.h" #ifndef  FileHandler_h #define FileHandler_h  using namespace std; template<class T> class FileHandler    {      public:string writeToFile(T writeObject);  public: FileHandler();     };   #endif   File Handler Class Implementation  template<class T> FileHandler<T>::FileHandler(){}  template<class T> string FileHandler<T>:: writeToFile(T writeObject) {     ofstream outputFile;    outputFile.open("file.txt",ios::out|ios::app);   more code..........       return "done";  }   Here is the code where i call the method in filehandler class  string Administrator::registerNewMember(Administrator newAdmin) {    FileHandler<Administrator> f1;      return f1.writeToFile(newAdmin);  }   Below is a screen shot of the error which i get.    How do i fix this error?


Let $f:[0,1]\rightarrow[0,1]$ and $g:[0,1]\rightarrow[0,1]$ be continuous functions satisfying $f\circ g =g\circ f$. Prove that there is a point $x\in [0,1]$, such that $f(x)=g(x)$.  I have thought two things  1) I have that for every continuous function $f:[0,1]→[0,1]$ there exists $y∈[0,1]$ such that $f(y)=y$, then $f,g, f\circ g$ have fixed points.  2)let $h(x)=f(x)-g(x)$ if there exists $a,b \in [0,1]$ such that $h(a)<0$ and $h(b)>0$ Hence, by the intermediate value theorem, $h$ must equal $0$ at some point $c \in [0,1]$.  the problem is that I can not find a, b that meets those conditions.


Why is the sign convention used in the derivation of the lens formula and yet used again when it is applied in numerical problems? Won't the whole idea of sign convention be eliminated if it is used twice?


Me and my husband applied for Greece visa 15 days ago, and we got rejected.  Reason:   The information submitted regarding the justification for the purpose and conditions of the intended stay was not reliable.  Your intention to leave the territory of the member states before the expiry of the visa could not be ascertained.    We got Schengen visa in the past, and UK visa as well.  What should we do?   And if we want to reapply for visa, should we apply at the Greek embassy or another embassy in the Schengen catagory?


It is currently said that MD5 is partially unsafe. Taking this into consideration, I'd like to know which mechanism to use for password protection.  This question,   suggests that hashing multiple times may be a good idea, whereas  suggests using salt.  I'm using PHP. I want a safe and fast password encryption system. Hashing a password a million times may be safer, but also slower. How to achieve a good balance between speed and safety? Also, I'd prefer the result to have a constant number of characters.   The hashing mechanism must be available in PHP It must be safe It can use salt (in this case, are all salts equally good? Is there any way to generate good salts?)   Also, should I store two fields in the database (one using MD5 and another one using SHA, for example)? Would it make it safer or unsafer?  In case I wasn't clear enough, I want to know which hashing function(s) to use and how to pick a good salt in order to have a safe and fast password protection mechanism.  Related questions that don't quite cover my question:


Navigate to the next question in the context?

Is there a userscript/browser plugin to add/create a hotkey/link to navigate to the next question in the current context?  Every time I search stackoverflow site or scan through a tag / list of newest questions I have to go to search results or index to open next question.  RSS reader allows quick browsing browsing through questions with hotkeys but lacks functionality of full-blown site. Moreover its inconvenient to subscribe to a tag you are not going to visit tomorrow.  There are , but they lack this functionality.  for this functionality to be implemented on the site and I'm looking for any kind of solution.


Show that $\lim_{m \rightarrow \infty}(\frac{4^m}{2m \choose m} \mathbb{P}(X = m + k))^m = e^{-k^2}$

I have been having some trouble solving the following problem:  Let $X$ be a Binomial $B(\frac{1}{2},n)$ random variable, where $n = 2m$. Let $$a(m, k) = \frac{4^m}{2m \choose m} \mathbb{P}(X = m + k) $$  Show that $\lim_{m \rightarrow \infty}(a(m, k))^m = e^{-k^2}$.  My attempt thus far has been the following:  $$\lim_{m \rightarrow \infty} (a(m, k))^m $$  $$= \lim_{m \rightarrow \infty} (\frac{4^m}{2m \choose m} \mathbb{P}(X = m + k))^m$$  $$= \lim_{m \rightarrow \infty} (\frac{4^m}{\frac{n!}{m!m!}} \frac{n!}{(m+k)!(m-k)!}(\frac{1}{2})^{m+k}(\frac{1}{2})^{m-k})^m$$  $= \lim_{m \rightarrow \infty} (\frac{m! m!}{(m-k)!(m+k)!})^m$$  I have tried to simplify this further to no avail.  Any help is appreciated.   EDIT following the hint (link) from the comments:  $$\lim_{m \rightarrow \infty} (\frac{m! m!}{(m-k)!(m+k)!})^m$$  $$= \lim_{m \rightarrow \infty} (\frac{(1-\frac{1}{m})(1-\frac{2}{m})...(1-\frac{k+1}{m})}{(1+\frac{k}{m})(1+\frac{k-1}{m})...(1+\frac{1}{m})})^m$$  $$= \lim_{m \rightarrow \infty} \frac{e^{-k}}{e^k}$$  $$= e^{-k^2}$$  as desired.  Where the fact that $e^x = \lim_{n \rightarrow \infty}(1 + \frac{x}{n})^n$ was used.


My Update Manager in Ubuntu 12.04 pops up this message while installing updates: 'Requires installation of untrusted packages. The action would require the installation of packages from not authenticated sources'. In Details: 'gnome-control-center gnome-control-center -data libgnome-control-center'  How to solve the problem?  Thankyou. :)


I tried to open an older file with inserted  figures in .emf files (actually created automatically by LyX when inserting copied pictures). I wonder why new LyX 2.1.3 allows inserting but does not see them in the file and does not want subsequently to compile them into pdf.  I can convert these .emf files into pdf files, but for me .emf files were more convenient since where formatted automatically by LyX (width and height, etc.).  Is it possible somehow to solve this problem without changing .emf files?


How do scientists determine how much sleep a particular individual needs?

Is it determined the same way as "healthy" weight?  Someone told me that for weight, they do it by measuring a large number of people and see who gets sick and who doesn't and correlate that weight.    Then I was in a forum where someone was saying the requirements are different and some can have 6 hours and be okay and some need 9 hours and I been googling for a few hours but can't find out how doctors would determine that, like is there a list of studies where they looked at different ages, men vs women, different personalities, race, etc, and how much sleep they need?  I read in a couple of places that women need more sleep but couldn't find the study that proved that.  One site mentioned Duke university but no link to the study.


Different lines that run on top of each other show as different lines

Imagine I have some bus lines each with a different colour, and sometimes the different bus lines run on the same road, but I don't want one of them to disappear. Is it possible to make them show as parallel like in the picture?  If I just simply draw the lines in parallel to each other, they will change appearance a lot as a zoom in or out and I would not have a consistent width between them.


Best approach for un-installing SharePoint Designer 2013 from my windows server 2008 R2

I have two SharePoint farms; Live & Test. both have the following software specification.   SharePoint enterprise server 2013, with SP1. installed inside windows server 2008 R2.   Now when I built our Live & Test servers, I had installed SharePoint Designer 2013, but lately I have read many articles which mentioned that it is recommended not not install any office or other application other than SharePoint inside SharePoint servers. So now I am planning to uninstall SharePoint Designer. Now on our Test server, I followed these steps:   Control Panel. Uninstall a program. select SharePoint Designer 2013. click on remove.   SP Designer got uninstalled correctly but not sure if this is the recommended way to uninstall SP designer. Now I am planning to uninstall SP designer on live server and could uninstalling SP designer cause any problem to SharePoint ?  Since both SharePoint service 2013 & SharePoint Designer 2013 are within the office suite, they might share some patches, updates and .dll files. So my concern if I uninstall SharePoint Designer inside the SharePoint server could this remove .dll or patches which is related to SharePoint or will uninstalling SharePoint Designer not affect SharePoint and will not conflict with the .dlls, patches related to SharePoint??


"Username or Password incorrect" Even though I use the correct email and password?

I can not log in to my Minecraft account. I have had the account for a few years now and have never had this problem. The unfortunate part is that I have never been able to log in the website, because I am asked security questions that I never had to set. However, now I am unable to even log into my account to play the game. I know that I am using the correct username and password. I put in the email used as opposed to my username, the same way that I have logged in since I got the account, I can log into my younger brothers account without a problem. I was just wondering if anyone else had the same problem I am having, and if anyone knew how to fix it.


QGIS 2.18 for mac: Processing NameError: global name 'QgsWKBTypes' is not defined

After installing the latest QGIS version for Mac (2.18.0), geoprocessing tools such as "Difference" and "Symmetrical Difference" are no longer working. Instead, the log window shows the following error message:      2016-11-14T14:28:43 2   Uncaught error while executing algorithm               Traceback (most recent call last):                 File "/Applications/QGIS.app/Contents/MacOS/../Resources/python/plugins/processing/core/GeoAlgorithm.py", line 203, in execute                   self.processAlgorithm(progress)                 File "/Applications/QGIS.app/Contents/MacOS/../Resources/python/plugins/processing/algs/qgis/Difference.py", line 71, in processAlgorithm                   geomType = QgsWKBTypes.multiType(QGis.fromOldWkbType(layerA.wkbType()))               NameError: global name 'QgsWKBTypes' is not defined   Does anyone have an idea what the problem might be and how to fix it?


Ubuntu stalls when accessing "System Settings" -> "User Accounts"

I currently have Ubuntu 14.04 but whenever I try to access "System Settings" -> "User Accounts" the OS just stalls there. I can still access other things. Is there a fix for this?


I'm new to GIS but have been learning QGIS for the last few months. I have Windows10/64bit system and I just installed the latest QGIS version 2.18.10, but now I get an error when attempting to run GRASS plugins from the processing toolbox. Error is as follows: "This algorithm cannot be run :-(  It seems that GRASS GIS 7 is not correctly installed and configured in your system. Please install it before running GRASS GIS 7 algorithms."  I have seen many post on this topic and have tried every suggestion to fix it to no avail.  I have completely uninstalled, including cleaning up the registry, re-installed 2.18.10 and still same issue.  I'm about to uninstall again and revert back to 2.18.08 which was working prior to this last update. But want to reach out and see if someone has a better solution prior to doing that.


What does the 'd' mean in ls -al results and what is that slot called?

In Linux, what does the d mean in the first position of drwxr-xr-x?  And what are all of the possible letters that could be there, and what do they mean?  I'm trying to learn more about the Linux file permissions system, and I'd like to see a list of the character meanings for the first slot.


How can I use an align environment flush left?

Is there a way possible to imitate the align environment for math mode commands, without having all writing being placed toward the center on the output page?  MWE:  \documentclass{article} \usepackage{mathtools}  \begin{document} \begin{align*} \cos\theta_1 \cos\theta_2-\sin\theta_1\sin\theta_2 &= \cos(\theta_1 +\theta_2) \\ \sin\theta_1 \cos\theta_2 + \cos\theta_1 \sin\theta_2 &= \sin(\theta_1+\theta_2) \end{align*}  \end{document}


I need help with this code  It is my first time using latex   \documentclass[10pt]{article} \usepackage{tikz} \usetikzlibrary{calc} \usepackage{graphicx} \usepackage{listings} \usepackage{pgfplots} \usepackage{calc} \usepackage{pdfpages} \usepackage{circuitikz}  \begin{document} \begin{figure}[h] \begin{minipage}[r]{0.49\textwidth} \centering \begin{tikzpicture}[scale=0.8] \begin{axis}[grid=magor, grid style={smooth}, xmin=0,xmax=3, xlabel=$t$, ylabel={$x(t),y(t)$}, variable=t] \addplot[blue,line width=1,smooth]plot [domain=0:3.5,samples=350]expression{(1+2t)exp(-2t)\sin(200t 3.14)}; \addplot[red,line width=1,smooth,style={dashed}]plot [domain=0:3.5,samples=150]expression{(1+2t)exp(-2t)}; \addplot[red,line width=1,smooth,style={dashed}]plot [domain=0:3.5,samples=150]expression{-(1+2t)exp(-2t)}; \end{axis} \end{tikzpicture} \caption{Damping sinusne funkcije} \label{damping} \end{minipage} \end{figure} \end{document}


Allow voting on Community Effort questions

There is a special type of questions marked as . For unobvious reason there is not possible to vote (or edit) on the question, since question is locked. But on the same time voting and edits are allowed on the answer. I see no reason why the voting is forbidden for the question. Can we make such questions vote available?   In my point of view community effort questions are not ordinary locked posts when voting/editing is prohibited according  from former SO employee.  In particular this limitation on voting prevents marking some questions as "community effort" by ruSO moderators:


Let $\omega = e^{\frac{2\pi i}{5}}$. Determine the Galois group $G = Gal(K/\mathbb{Q})$

Let $\omega = e^{\frac{2\pi i}{5}}$   prove that $K = \mathbb{Q}[\omega]$ is a splitting field for the polynomial $x^5-1$ over $\mathbb{Q}$ Determine the Galois group $G = Gal(K/\mathbb{Q})$ For each subgroup $H$ of $G$ (including $G$ and {Id}) describe explicitly the fixed field $K^H$ and determine $[K^H : \mathbb{Q}]$ and give a $\mathbb{Q}$-basis for $K^H$.   I have that all the fifth roots of unity are powers of $\omega$, thus $K = \mathbb{Q}[\omega]$ is a splitting field. Is this sufficient? As for the rest, I do not have much practice determining the Galois groups. Explicit direction would be much appreciated, as this is a guiding example for the rest of my work.


Given the supposed time-line of GOTG Vol.2 why did Stan Lee claim to have been a Fed-Ex man?

Perhaps an overly pedantic observation, however, in the Guardians of the Galaxy cameo Stan Lee claims to have been a Fed-Ex man. This is presumably a reference to the Stan Lee cameo at the end of Captain America: Civil War. In which Stan Lee is a Federal Express man who (humorously) calls Tony Stark "Tony Stank".  However, Guardians of the Galaxy: Vol.2 is supposed to take place soon after the events of GOTG Vol.1, long before Civil War and thus before Stan Lee's character poses as a Fed-Ex man. So what's the deal here? Is time travel involved? Has Stan Lee been a Fed-Ex man twice?


Boot into Windows after uninstalling Ubuntu (Dual-boot)

I had a Windows 7/Ubuntu dual-boot set up on my laptop. I deleted Ubuntu, and when I load up my computer, I am now met with a screen displaying the following:  error: no such partition. grub rescue>   How can I have my computer boot straight into Windows 7 again?  Solved: I created a win7 system repair disc using another machine, and fixed the problem using the bootrec command within command prompt.


Is $d|b$ and $d|a$ true in $d = l \cdot a + k \cdot b$

There are $a,b \in \mathbb Z, a \neq 0$ and $d$ which is the smallest number in $\mathbb N$ for that  $d = l \cdot a + k \cdot b$ is true.  ($k,l \in \mathbb Z$)  I think that $d|b$ and $d|a$ is true, but I can't find proof for it, can you?


I edited a new person's question and a user called Community accepted my edit?

This user . Is a moderator with this description:  Hi, I'm not really a person.  I'm a background process that helps keep this site clean!  I do things like   Randomly poke old unanswered questions every hour so they get some attention Own community questions and answers so nobody gets unnecessary reputation from them Own downvotes on spam/evil posts that get permanently deleted Own suggested edits from anonymous users Remove abandoned questions   It accepted my edit . But why?


What is the difference between "He saw me talking" and "He saw me talk"?

Can anybody tell me the difference between the following two sentences:  He saw me talking to her. He saw me talk to her.  Please let me know if both the statements are valid and grammatically correct. If valid, please explain the meaning of both the statements and what is the difference between the two.


Javascript write regular expression to substitute http with html tag

How do I make this string text  first video link: https://www.youtube.com/watch?v=123456  second video link: https://www.youtube.com/watch?v=8123123`;   become   first video link:     https://www.youtube.com/watch?v=123456   second video link:     https://www.youtube.com/watch?v=8123123    I have written a regular expression to parse the link  Here is what I have.


What do Murph and NASA do to save humanity after solving Brand's equation?

In Interstellar, what do Murph and NASA do to save humanity after solving Brand's equation? Do they get the entire human race on giant space ships and transport them to a habitable planet? (How exactly do they do  this?)  If yes, is this habitable planet Edmunds' (the one that Amelia lands on)?


Limit of $\frac{1}{x^2}-\frac{1}{\sin^2(x)}$ as $x$ approaches $0$

Evaluate   $$\lim \limits_{x \rightarrow  0}\left(\frac{1}{x^2}-\frac{1}{\sin^2(x)}\right)$$   I tried to combine the fractions $$\frac{1}{x^2}-\frac{1}{\sin^2(x)} = \frac{\sin^2(x)-x^2}{x^2\sin^2(x)}$$ and apply L'Hopitals which only made a mess.  I feel like there is a simpler way of doing this but I'm not quite sure what to do


difference of "have been working" and "have worked"

I have a question. Yeah it is kinda easy but it made me a bit confused. My teacher said: "I've worked at there for 3 years." implies, I've worked 3 years and I still work at there. But as I know, if we want to imply that we must say:  "I've been working there for 3 years." Does "I've worked there for 3 years."  mean I still work at there? Or which one is correct? in this case, I'm tend to say "I've been working". And probably it's my mistake of having lack of information but "I've worked" seemed to be like "I'm not working here anymore" for me. Which one is better?


I have raspbian running on my raspberry PI. When I switch it on, boot messages crawl on the screen. I believe it would be beneficial to read them in order to get an idea about how the system starts. Hence I would like to know whether it is possible (and how) to redirect them to a file in order to read them thoroughly afterwards. Do I have to make a script that runs at startup?


Labeling a point at which a perpendicular is dropped

I saw the following code for drawing a triangle separated into two right triangles used in a demonstration of the Pythagorean Theorem.  What does the code \tkzDefPointWith[orthogonal normed,K=7](C,A) instruct TikZ to typeset?  How can I add "P" to the picture at the point that (dotted) line segment from C intersects line segment AB?  I guess that I use the command \tkzLabelPoint. What is the optional argument to position P? After I label this point, I guess that I can have TikZ draw a right angle at this intersection with a command like \tkzMarkRightAngle(C,P,B).  \documentclass{article} \usepackage{tkz-euclide} \usetkzobj{all}  \begin{document}  \begin{tikzpicture} \tkzDefPoint(0,1){A} \tkzDefPoint(2,4){C} \tkzDefPointWith[orthogonal normed,K=7](C,A) \tkzGetPoint{B}  \tkzLabelPoint[left](A){$A$} \tkzLabelPoint[right](B){$B$} \tkzLabelPoint[above](C){$C$}  \tkzMarkRightAngle(A,C,B)  \tkzDrawSegment[green!60!black](A,C) \tkzDrawSegment[green!60!black](C,B) \tkzDrawSegment[green!60!black](B,A)  \tkzLabelSegment[auto](B,A){$c$} \tkzLabelSegment[auto,swap](B,C){$a$} \tkzLabelSegment[auto,swap](C,A){$b$}  \tkzDrawAltitude[dashed,color=magenta](A,B)(C) \tkzGetPoint{P}  \tkzMarkAngle[size=1cm,color=cyan,mark=|](C,B,A) \tkzMarkAngle[size=1cm,color=cyan,mark=|](A,C,P) \tkzMarkAngle[size=0.75cm,color=orange,mark=||](P,C,B) \tkzMarkAngle[size=0.75cm,color=orange,mark=||](B,A,C) \end{tikzpicture}  \end{document}


Assuming you have classes like Player, Enemy, Map and Tile.  The first approach to structuring rendering code would be to give each a render() method and let it draw itself:  void render(){    player.draw();    enemy.draw();    // etc. }   But considering the  perspective, that feels wrong... Another idea would be to make a Renderer class, but then I wonder how you give the Renderer information what to draw.  Which one should I choose and why?


Stochastic process that is Martingale but not Markov?

Can you please help me by giving an example of a stochastic process that is Martingale but not Markov process for discrete case?


I need help identifying an SMD component it is a small(1 mm X 1.5 mm)  black part with an "O" written on top if it. I think it is a Schottky diode for reverse polarity protection ?.  (, first part on codes beginning with O)  I have attached an image if that helps  The component in question is marked J2/J3 on the silk screen. Also, if it helps the image is of a remote control pcb.  PS: This is my first post so please let me know if i did something wrong :)


What causes striped visual artifacts in models?

I don't know the legitimate term for them, but I'm referring to the "shaded" or "stripy" regions that appear that can appear in your models (see the picture below)  Here is a contrived example deliberately created to reproduce the artifacts:     What are these artifacts called? I did a few google searches to learn more about this but came up short because I can only describe them as "visual artifacts" which is too broad.  What is causing these artifacts to appear? In both cases there are overlapping faces, but what causes Blender to show them in the way that it does? To approach from another angle: why could Blender not "simply" ignore overlapping faces? Are there general strategies one would take to fixing these issues? If so, what?   Even a link to a resource that explains this would be appreciated.


Thesis adviser is demanding i hand over all my work

My Masters adviser (computer science) is demanding I hand over all my work including data sets, code and configurations. I do not want to be overly specific just in case. This seems fishy... or am I paranoid.    Notes:   He demanded that "we" publish an additional paper in addition to the thesis. I told him that I did not have time for anything beyond the department requirement of a thesis. He got mad and now its been one thing after another each week. Now, he wants the entire project handed over. The entire experience since my decline of additional paper has been hostile.


How did Sherlock know the combo for Adlers safe?

Adler said it was her measurements, but what does that mean?


I've got this task to prove that, given $\forall x \geq a$ :  f is monotonically decreasing,  $ f \geq {0}$  $\int_a^\infty f(x)dx $ converges.  Then $\lim\limits_{x\to\infty}xf(x) = 0 $  I proved successfully that $\lim\limits_{x\to\infty}f(x) = 0$ but I don't know if it helps me anyhow.


Is there a function/method in JavaScript to get detailed information about the content of a variable?

I'm wondering if there is a function or method in JavaScript such as var_dump() in PHP that prints or returns detailed information about the content of a variable, i.e. value(s) and data type. Especially in case of more complex data types like arrays and objects such a function would be very helpful...


What is the difference between Oracle JDK 8 and Open JDK 8?

There are two kind of JDK available for Ubuntu(Oracle JDK 8 and Open JDK 8).  Which one is recommended for programmer to install ?


Are $+\infty$ & $-\infty $ elements of the real number line?

Can someone give an explanation/proof of whether these two numbers lie on the real number line?


How can i eliminate the edges from this mesh?

I'd want to extrude the face go this mesh but i can't understand how to eliminate the edges inside it


Getting spatially referenced tiles from WMTS

I have been able to download tiles from a WMTS request in .tif format using owslib in standalone python:  from owslib.wmts import WebMapTileService  wmts = WebMapTileService('wmts_url') img = wmts.gettile(layer='v0Lw1953KMdH',                    tilematrixset='WGS84',                    tilematrix='16',                    row='20480',                    column='32001',                    format='image/tif')  out = open('C:\\out\\test_out.tif', 'wb') bytes_written = out.write(img.read()) out.close()   This .tif file is not spatially referenced. The WMTS Layer has the tag:   <ows:WGS84BoundingBox crs="urn:ogc:def:crs:OGC:2:84">     <ows:LowerCorner>-7.793077 49.852539</ows:LowerCorner>     <ows:UpperCorner>1.790425 60.894042</ows:UpperCorner> </ows:WGS84BoundingBox>   and the WMTS TileMatrixSet has the tag:  <ows:Title>WGS84</ows:Title> <ows:Abstract>WGS84 EPSG:4326</ows:Abstract> <ows:Identifier>WGS84</ows:Identifier> <ows:SupportedCRS>urn:ogc:def:crs:EPSG::4326</ows:SupportedCRS>   which to someone of my limited knoweledge indicates that there could be a way to obtain a spatially referenced .tif from these tiles. However, I haven't been able to obtain a spatially referenced .tif, despite trying to include the crs in gettile(). Where am I going wrong?  Failing this, are there any other methods that I could use to obtain spatially referenced tiles?


annotation to make a private method public only for test classes

Who has a solution for that common need.  I have a class in my application.  some methods are public, as they are part of the api, and some are private, as they for internal use of making the internal flow more readable  now, say I want to write a unit test, or more like an integration test, which will be located in a different package, which will be allowed to call this method, BUT, I want that normal calling to this method will not be allowed if you try to call it from classes of the application itself  so, I was thinking about something like that  public class MyClass {     public void somePublicMethod() {     ....    }     @PublicForTests    private void somePrivateMethod() {     ....    } }   The annotation above will mark the private method as "public for tests" which means, that compilation and runtime will be allowed for any class which is under the test... package , while compilation and\or runtime will fail for any class which is not under the test package.  any thoughts? is there an annotation like this? is there a better way to do this?  it seems that the more unit tests you write, to more your inforced to break your encapsulation...


How to install WPS Office via Command Line

I'm following  guide to install WPS Office but when I run the dpkg command, the following appears in the terminal:  (Reading database ... 291111 files and directories currently installed.) Preparing to unpack wps-office.deb ... Unpacking wps-office (10.1.0.5672~a21) over (10.1.0.5672~a21) ... dpkg: dependency problems prevent configuration of wps-office:  wps-office depends on libpng12-0; however:   Package libpng12-0 is not installed.  dpkg: error processing package wps-office (--install):  dependency problems - leaving unconfigured Processing triggers for bamfdaemon (0.5.3+17.04.20170406-0ubuntu1) ... Rebuilding /usr/share/applications/bamf-2.index... Processing triggers for gnome-menus (3.13.3-6ubuntu5) ... Processing triggers for desktop-file-utils (0.23-1ubuntu2) ... Processing triggers for mime-support (3.60ubuntu1) ... Processing triggers for shared-mime-info (1.8-1) ... Processing triggers for hicolor-icon-theme (0.15-1) ... Errors were encountered while processing:  wps-office   Then, when I run:  sudo apt-get install -f && rm wps-office.deb   The following is output:  Reading package lists... Done Building dependency tree        Reading state information... Done Correcting dependencies... Done The following packages will be REMOVED:   wps-office 0 upgraded, 0 newly installed, 1 to remove and 1 not upgraded. 1 not fully installed or removed. After this operation, 367 MB disk space will be freed. Do you want to continue? [Y/n] n Abort.   I switched to Ubuntu from ChromeOS about a week and a half ago so this is all very new to me and any help you can give would be greatly appreciated.


Convergence of $ s_n$ : if $s_{2n}$ increases and $s_{2n-1}$ decreases .

We have a sequence $(s_n)$ such that $s_1>s_2>0$ and $s_{n+1}=\frac{1}{2}(s_n+s_{n-1})$ for $n \geq 2 $ . Show that $s_n$ converges ?  I have first observed that $s_{2n}$  increases and $(s_{2n+1})$ decreases and also proved it by finding difference between  any two consective terms .  But , how shall I prove the convergence of $s_n$ and converges to what ? (in terms of $ s_1$ and $s_2$ ) .   I want to do it by using the observations which was provided as   Hint : $s_{2n}$  increases and $s_{2n+1}$ decreases .  I already proved convergence of $s_n$ but it converges to what value ?


Is "singer of the band's wife" a correct alternative to "wife of the band's singer"?

Isn't this sentence:     He stole the singer of that band's wife.   a wrong attempt at saying:     He stole the wife of that band's singer.   Someone pointed this out:     The <singer of the band>'s wife is the wife of the <singer of the band>. The wife of the <singer of the band> is the wife of the <band's singer>.      Apostrophes aren't that hard.   I guess my question is - can you place an 's targeting a previous, but not necessarily the last word in a sentence?  Thanks.


Prove that $\mathbb{R}$ and the interval $(0, \infty)$ have the same cardinality.

Prove that Real Numbers and the interval $(0,\infty)$ have the same cardinality.   Attempt:  Consider the function $f(x) = e^x$.   The domain of this function is all real numbers.  The range of this function is from $0$ to infinity.   Let $e^a = e^b$.   Then $\ln(e^a) = \ln(e^b)$  Then $a\ln(e) = b\ln(e)$  This means that $a = b$  Hence, $f$ is injective.   Let $c > 0$   Then $e^{ln(c)} = c$  Since $c > 0, \ln(c)$ is defined, so $f(\ln(c)) = c$  Therefore, f is surjective.   Then f is bijective.   Hence, $\mathbb{R}$ and $(0, \infty)$ have the same cardinality.


Characteristic polynomial of a matrix of $1$'s

I am trying to calculate the characteristic polynomial of the $n \times n$ matrix $A = \{ a_{ij} = 1 \}$.  Case $n=2$: I obtained $p(\lambda)=\lambda^2-2\lambda$ .  Case $n=3$: I obtained $p(\lambda)=-\lambda^3+3\lambda^2$.  Case $n=4$: I obtained $p(\lambda)=\lambda^4 - 4\lambda^3$.   I guess that for the general case, we have $$p(\lambda)=(-1)^n\lambda^{n}+(-1)^{n-1}n\lambda^{n-1}$$ I tried to use induction, but it didn't work, unless I've done wrong. Can somebody help me? Or give me a hint?


JPA/Hibernate: What's better for composite primary keys, @IdClass or @EmbeddedId implementations and why?

what's better for JPA/Hibernate composite primary keys, @IdClass or @EmbeddedId implementations and why? This is an intentionally naive question. I decided to use @EmbeddedId (for whatever reason) and I feel like I made the wrong choice. Dereferencing the embeddedId that contains the column properties is redundant and quite error-prone when coding. Are there any more reasons for and/or against the other? Is the a recommendation by the JPA (spec)?


How to install Ubuntu on a blank hard drive?

Do I have to install the drivers for my computer in order to install this OS?   My hard drive has no OS on it.


Terminal - permission denied - logged in as admin

I have some tenacious problem with installing my printer driver since I set up Ubuntu 14.4 new. Until this time everything worked fine and I could use/install the printer driver successfully . Also I am quite sure, that I didn't change any settings. Now it isn't possible anymore to install the driver again. Every time I get the message "permission denied".  I read about the problem of access rights and how to show/change setting. At this point I am not sure. I am logged in as admin and if i show right settings for "install.sh" this is shown:  jam@jam-GA-880GM-USB3:/media/jam/Western Digital WD20/Software/Samsung Druckertreiber/Ubuntu-Linux/uld$ ls -l insgesamt 19 drwx------ 1 jam jam 4096 Dez 12  2014 i386 -rw------- 1 jam jam  446 Dez 12  2014 install-printer.sh -rw------- 1 jam jam  446 Dez 12  2014 install-scanner.sh -rw------- 1 jam jam  848 Dez 12  2014 install.sh drwx------ 1 jam jam 4096 Feb 10  2015 noarch -rw------- 1 jam jam  328 Dez 12  2014 uninstall-printer.sh -rw------- 1 jam jam  328 Dez 12  2014 uninstall-scanner.sh -rw------- 1 jam jam  383 Dez 12  2014 uninstall.sh drwx------ 1 jam jam 4096 Dez 12  2014 x86_64 jam@jam-GA-880GM-USB3:/media/jam/Western Digital WD20/Software/Samsung Druckertreiber/Ubuntu-Linux/uld$ ^C   If a go to properties of the file "install.sh" there is written "read and write" for me/admin. But for "jam"-account there is only "none". But "jam" is my admin-account. If i want to change settings for "jam"-account, it imediately jumps back to "none". Only of I copy the file "install.sh" to the hard disk, I can change the access rights to "read and write". But also I get the message "permission denied" when I try to install.  So a lot of text. I wrote every backround information to help professional ubuntu users here to help me. I hope


Can you change the list builder class used by an entity?

There's an entity created by another module and I'd like to change some of the fields used on a listing page. Currently that page is using the entity's list builder class. Is there a way I can define a new list builder class, make my changes, and use that for this entity? I have tracked this down to where D8 get's entity definition and loads the list builder class from that. I can't find a way to alter the definitions or another way to inject a different class here.  In more specific terms, I have  and want to override the functionality around EckEntityListBuilder.