As part of my work (programmer), I need to learn some linear regression. I have a degree in pure mathematics, but not in statistics. Could anyone be able to give me a good book, an introduction, in linear regression?  Thanks in advance!

I watched several videos on linear regression, mainly from . As I have no background in statistics, I thought this was a good way to get an idea of the topic. However I'm currently writing a bachelor thesis on Structural Equation Modeling and I want to get a deeper understanding of Regression Analysis.  The Book should roughly include these topics:   linear least squares regression variance, covariance regression coefficient coefficient of determination residual analysis (esp. leverage effect) multiple regression   I especially enjoyed the videos on khan academy, of the proof of minimizing the squared error to the regression line or illustrations like this one from Wikipedia:    I don't like it when books only present a formula and some common rules etc. without any further explanation of these.  F.e. Residuals should be normally distributed.  However I'm also not comfortable with strictly mathematical books, so I'm searching for something in between. A plus would be example code in R, but definitely not a must have.


I wrote a review of the movie Detroit  and in the section What irked me about the film, I started in the following fashion: -  No doubt, Detroit is an engrossing flick, its greatest problem lied in the fact that it runs much longer than it should have.  A friend of mine pointed out that it should be lay instead of lied. I'm confused as to which form is correct and why? Thanks in advance for your help.

How do I know when to use lay and when to use lie, and what are the different forms of each verb? I'm always getting them confused.


What we know how to do and what we have done differentiate us from others.   or  What we know how to do and what we have done differentiates us from others.  Can anyone explain to me which is correct and why?

Which sentence is more grammatically correct?     He is being tried on what look like trumped-up charges.   He is being tried on what looks like trumped-up charges.


I have a line defined by two points within the line, $A(x_1, y_1, z_1)$ and $B(x_2, y_2, z_2)$.  I have a third point $P(x_3, y_3, z_3)$.  How do I find the coordinates of the points on the line $AB$ which are $d$ units away from $P$ ?

I would like to find a point $d$ away on a line from a starting point only given a slope. My fist thought was to use the distance formula ($d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}$), but I would have to solve for two variables. How can I solve find the point without graphing or brute forcing?


This is related to Apex API version, where Salesforce releases New versions. Is there any benefit of changing the current old API version of Apex class to the new API version? Does changing the version affect the functionality of Apex class? Is there any documentation or best practices for the Apex API version. Please comment thank you 🙂

I'm in the process of pushing some updates to some code I originally wrote 12-18 months ago, and the API Version is between 27.0 and 29.0  I know this is to protect the integrity of the test classes you've built (in case they have changed some things) but is there a best practice around either leaving these alone or trying to keep them up-to-date (maybe just once a year instead of at each release)?


I remember reading a short story in the 60/70's where there were two astronauts in spacesuits on an orbiting platform having some sort of dispute. One of them successfully threatens the other to by hurling him towards the planet whereby he believes that he doomed to keep falling. It turns out, however, that following orbital mechanics ( conservation of the center of gravity ) that the hapless astronaut will rejoin the platform halfway through the revolution. I thought this was a Clark or Asimov since it involved some real physics but I can't seem to locate the title.

Read it in an old collection that I can't recall.  Ultimately, a crew of astronauts find an empty alien structure/ship, and it is filled with tons of artifacts from their society.  There is some duplicity among the astronauts. I feel like its a Clarke story, but maybe not?


Prove or disprove.  Suppose that $g$ is a positive real valued function of a real number. If $a < b$ are real numbers, then there is a finite sequence $a = t_0 < t_1 \dots < t_n = b$ of real numbers such that in each interval $[t_k,t_{k+1}]$ there is a point where the value of the function $g$ is greater than the length of the interval.   Unfortunately, I am quite lost. I tried a contradiction proof, but I ran into a snag. Any help would be welcome.

I need to prove or disprove the following:  Suppose that $g$ is a positive real valued function of a real number. If $a < b$ are real numbers, then there is a finite sequence $a = t_0 < t_1 \dots < t_n = b$ of real numbers such that in each interval $[t_k,t_{k+1}]$ there is a point where the value of the function $g$ is greater than the length of the interval.   With out the assumption of continuity, I'm not sure how to proceed. Any advice?


I just upgraded from 16.04 to 18.04 and can no longer login as - or su to - root at the console. There used to be a specific configuration for this console restriction in System V Unix's IIRC. Logging in as a regular user works fine at the console and I can still su to root in SSH logins, although cannot login directly as root (I don't recall whether this worked in 16.04 - I just never did that, always logged in as a regular user first). Any ideas? TIA. To clarify: 'su' works fine in a remote shell, but not at the console. I'm getting: su: Authentication failure

How do I change from user to superuser (root)? What command do I use in the Terminal to switch to root? I have tried --help but I get lost with all the listed help. I'm looking for a recent download/install so I can use it.


I would like to know in which specific cases to use the USING statement, which is its main functionality when including it in the code.  In my case I am scheduling a job for the university, the project is about registering computers with their different data, I am currently preparing the database, but the professor recommends this sentence and I would like to know more about it

User  answered the wonderful  question by mentioning the using keyword. Can you elaborate on that? What are the uses of using?


I want to set default a specific program for open ANY files absolutely ANY(*.*), any extension, any mime type. ABSOLUTELY ALL  I build a python program to automated choose the program for any file. the app-chooser.py content:  #!/usr/bin/python import sys, os, os.path filename = sys.argv[1]; extension = os.path.splitext(filename)[1];  if extension == "txt":   os.system("gedit " + filename);  if extension == "mp4":   os.system("vlc " + filename);  if extension == "html":   os.system("opera " + filename);  if extension == ".py":   os.system("python " + filename);  if extension == ".sh":   os.system("bash " + filename);  if extension == ".exe":   os.system("wine " + filename);  exit()   The app-chooser.py are compiled in a standalone linux executable, located in "/usr/bin/app-chooser".

I want to use xdg-open to open irc:// links, how can I make the required parameter?


I have inserted a figure in my LaTeX document, and this figure comes from a document referenced in my bibliography. The problem is that this latter document has many pages, so I would like to quote in the title of my figure in which page of the document we can find it. I am using \bibliographystyle {acm}. Would that be possible to do?  This is what I have written in LaTex:  \begin{figure}[htb]  \capstart   \centering \includegraphics[width=1\textwidth]{Pictures/blablabla.pdf} \caption{On, based on \cite{as}} \label{fig:On} \end{figure}   And this is what appears in my PDF Document below my figure:     "Figure 2.1: On, based on [4]"   I would like to have this (or something similar):     "Figure 2.1: On, based on [4 p.38]"   Thanks in advance!

Is it somehow possible to put a citation including page specification, as in \cite[page]{book}, inside the list-of-figures-relevant caption of a figure, i.e. \caption[*HERE*]{...}?  I can do  \caption[\protect\cite{book}]{other text}   but  \caption[\protect\cite[page]{book}]{other text}   yields book] other text as the caption in the first run and produces an error "Argument of \NAT@@cite has an extra }" in the second LaTeX run.  I'm using pdfLaTeX and natbib.


Why is light affected by gravity even though it is massless?

I understand that a black hole bends the fabric of space time to a point that no object can escape.   I understand that light travels in a straight line along spacetime unless distorted by gravity. If spacetime is being curved by gravity then light should follow that bend in spacetime.  In Newton's Law of Universal Gravitation, the mass of both objects must be entered, but photon has no mass, why should a massless photon  be affected by gravity in by Newton's equations?  What am I missing?


I've been playing Fallout Shelter a lot lately. I'd like to know how you get pet carriers. Is it only from in app purchases or can the be unlocked? I recently unlocked the fitness room if that gives any indication.

Fallout Shelter has a new feature where your Dwellers can also have a Pet. Is there a way to get more pets without purchasing them? Can you find them in the wasteland?


I would like to install Ubuntu on real hardware, but I don't have a suitable USB or DVD. Would the  still work now? I have Windows 10 and want to dual-boot.

The reason that I cannot use a usb or cd is because the 'xHCL Compliant Host Controller' is not working on my laptop. I have tried every methods I could find, even resetting my laptop to factory settings as a last resort. But, to reset my laptop, I got rid of my Ubuntu partition and I've been looking for a solution to get it back. I have tried Unetbootin as I've seen recommended online, but I get this error from the Windows boot manager while trying to boot using unetbootin: note: i was trying to install ubuntu 20.04 on my disk using ubuntu, as shown here: . However this was to dual boot with Windows 7, and I have Windows 10 so maybe that is the problem? Windows failed to start. A recent hardware or software change might be the cause. to fix the problem:      1. Insert your windows installation disc and restart your computer.   2. Choose your language settings, and then click "Next."   3. Click "Repair your computer."  If you do not have this disk, contact your system administrator or computer manufacturer for assistance.      Files: \ubnldr.mbr          Status: 0xc000007b      Info: The application or operating system couldn't be loaded because a required file is missing or            contains errors   If anyone knows whether it is feasible to install ubuntu on my laptop without a USB or DVD, or if you have any ideas on how to make it work, let me know! my laptop: ASUS UX330UAK Windows version: 10.0.18363 Build 18363 BIOS mode: UEFI Let me know what other information is needed! NOTE: I see a lot of discussions about this topic where people just say "just use a USB" but that is NOT possible in my case, and I can't use a DVD either (I don't have a slot for it). Similarly, SD cards also do not work. I am not looking for a solution to fix my USB driver (or whatever it is that isn't working) since I spent two days in the guts of google trying all the different solutions, I doubt there is a solution I haven't tried. Sending my laptop to the manufacturer is not an option as I need it everyday for classes and work.


In researching the best practice for adding sites to the Search Console, I've often seen it suggested to add separate properties for different versions of the same website. Even in  it states:     "Similarly, if your site has http:// and https:// versions, you should   add each as a separate site."   I've seen the same suggested for www/non-www. So if a site is accessible at all the variations of http/s and www/non-www we should have four properties.  But what if the site is only accessible at one variant? i.e. https and www are forced via htaccess, so only  can ever be accessed - should we still add all the variants?   In essence, the problem is that I don't know why Google wants us to do this, so I can't work out if it'll be ok just to have one instance.

In my site I'm redirecting everything (http://, http://www., https://) to https://www.example.com.  Google webmaster tools says: Make sure you add both "www" and "non-www" versions for your site. Also, if you use the HTTPS protocol, add those variations as well.  So I've added all the FOUR versions to google webmaster tools. Is this a correct process?


When regressing a dependent variable y on some feature vector x with a standard linear regression, is there any correction in place for multiplicity or is this just not relevant in this case? The motivation for this question is that when I run several regression specifications (e.g. with or without interaction effects), I know that I have to perform some correction for the multiple testing to correct confidence intervals and p values (e.g. Benjamini-Hochberg Correction). Now when I have a feature vector with e.g. 10 different independent variables, is estimating their coefficients equivalent to multiple testing?

Say I fit a multiple regression of p explanatory variables. The t-test will allow me to check if any single one of those is significant ($H_0: \beta_i = 0$). I can do a partial F-test to check if some subset of them is significant ($H_0: \beta_i=\beta_j=...=\beta_k=0$).  What I often see though is that someone gets 5 p-values from 5 t-tests (assuming they had 5 covariates) and only keeps the ones with a p-value < 0.05. That seems a bit incorrect as there really should be a multiple comparison check no? Is it really fair to say something like $\beta_1$ and $\beta_2$ are significant but $\beta_3$, $\beta_4$ and $\beta_5$ are not?   On a related note, say I run 2 regressions on 2 separate models (different outcome). Does there need to be a multiple comparison check for significant parameters between the two outcomes?  Edit: To differentiate from the similar question, is there any other interpretation to the p-values besides: "B_i is (in)significant, when adjusting for all the other covariates"? It doesn't seem that this interpretation allows me to look at every B_i and drop those less than 0.5 (which is similar to the other post).   It seems to me that a sure fire way to test whether B_i and Y have an a relationship would be to get a correlation coefficient p-value  for each covariate and then do a multcomp (although that would definitely lose signal).  Finally, say I computed the correlation between B1/Y1, B2/Y1 and B3/Y1  (thus three p-values). Unrelatedly, I also did a correlation between T1/Y2, T2/Y2, T3/Y2. I'm assuming the correct Bonferroni adjustment would be 6 for all 6 tests together (rather than 3 for the first group and 3 for the second group - and thus getting 2 "semi"-adjusted p-values).


Update 19.June.2020: Alexei Levenkov suggested  - my issue may have nothing to do with threading. I've been using C# for almost 20 years and never knew this and have never knowingly been affected by it. Now I'm a little worried about everything that I've ever done...Thanks Alexei! I have some C# code that creates threads to pass parameters to a method to page through some data. One of those parameters to the method is the counter for the loop that creates the threads. Using Console.WriteLine(), I can see that the value to pass to the method is 0 on the first iteration, but the method receives 100, which is the value of the increment for the loop, as if it's receiving the value after the subsequent iteration of the loop or the iterations are sharing a framestack or whatever somehow. It seems impossible because skup is just a value type int. I do not have this problem when Repository.Configuration.UseThreading is false. I am not very familiar with threading, so I wonder what I have told it to do that could cause this. I tried creating an Int32 from skip just to pass to the method but had the same result. Whatever the issue is, it's hard for me to understand the consequences where I pass other parameters. The first thing the method in the thread does is show the value that it recives, which is 100: private void LoadBatch(EntryPointer entryPointer, ContentTypeWrapper contentTypeWrapper,     int skip, Action<EntryPointer> action) {     Console.WriteLine("LoadBatch: " + skip);     //...  Here is the code that creates the threads: foreach (ContentTypeWrapper contentTypeWrapper in contentTypeWrappers) {     if (contentTypeWrapper.EntriesLoaded == contentTypeWrapper.EntryCount)     {         Repository.Instrument.Warn(this, $"contentTypeWrapper.ContentTypeUid"             + $" already loaded or {contentTypeWrapper.EntryCount} entries; skip");         continue;     }      for (int skip = 0; skip < contentTypeWrapper.EntryCount;         skip += Repository.Configuration.QueryLimit)     {         if (Repository.Configuration.UseThreading)         {             new Thread(() => LoadBatch(entryPointer, contentTypeWrapper, skip, action))                 .Start();         }         else         {             LoadBatch(entryPointer, contentTypeWrapper, skip, action);         }     }  If I make this change, it works the way that I would expect: for (int skip = 0; skip < contentTypeWrapper.EntryCount;     skip += Repository.Configuration.QueryLimit) {     int mySkip = skip;      if (Repository.Configuration.UseThreading)     {         Console.WriteLine("Passing to LoadBatch: " + mySkip);         new Thread(() => LoadBatch(entryPointer, contentTypeWrapper, mySkip, action))            .Start();

I met an interesting issue about C#. I have code like below.  List<Func<int>> actions = new List<Func<int>>();  int variable = 0; while (variable < 5) {     actions.Add(() => variable * 2);     ++ variable; }  foreach (var act in actions) {     Console.WriteLine(act.Invoke()); }   I expect it to output 0, 2, 4, 6, 8. However, it actually outputs five 10s.  It seems that it is due to all actions referring to one captured variable. As a result, when they get invoked, they all have same output.  Is there a way to work round this limit to have each action instance have its own captured variable?


A single word for the person who repeats same mistake again and again.

Is there a word or phrase that means someone who doesn't learn from his mistakes or makes the same mistakes again? It can be a noun or adjective or anything that implies the meaning.


Basically, I am trying to increment the int value of port. This should be easy but I am a little stuck.    It compile fine, but I got this error when I run it:  Access violation writing location 0x001f5834   #include "stdafx.h" #include "iostream"  using namespace std; #define TESTING "5002" int main() {     char* port = TESTING;     int portint;     sscanf ( port, "%d", &portint );     portint++;     cout << portint << endl; // it works fine up to here, it prints 5003     sprintf ( port, "%d", portint);     return 0; }

The following code receives seg fault on line 2:  char *str = "string"; str[0] = 'z';  // could be also written as *str = 'z' printf("%s\n", str);   While this works perfectly well:  char str[] = "string"; str[0] = 'z'; printf("%s\n", str);   Tested with MSVC and GCC.


In latex text mode \^{} puts hat on characters but i need to put hat on greek letters in text mode. How can I put the symbol hat over a greek letter in text mode?

I am trying to type a circumflex over a Greek letter in \chapter. In particular, I'm using this package:  \usepackage{textgreek}   However, if I write \^{\textPi} I get this result:    while I want the circumfex to be over the letter. Can anyone help me to solve this issue?


When edit list of my sites I see too large vertical space between already added sites:     App Version: 1.0.89 Device Manufacturer: LGE Device Model: LG-D802 OS Version: 5.0.2 (152331922a212)

There is some unwanted extra spaces in between each site in the Your Sites section.  Steps to reproduce:   Touch the Nav Icon in the left top corner Touch the EDIT link in YOUR SITES Scroll the screen; there is unwanted spaces in between the each site   For reference I recorded the same:    Configurations:   App Version: 1.0.85 Device Manufacturer: Motorola Device Model: XT1033 OS Version: 5.1 (2)


I know that in order to successfully cast AK, you need to mean it and have a powerful mindset at that moment.   However during DH, in the RoR Crabbe is using it twice in a really short period toward Hermione.  My question is, why doesn't Voldemort/Bellatrix/other powerful Death Eaters spam AK to kill.  One could argue that Bellatrix likes to "play with her food before eat it" and Voldemort wants to prove that he's above everyone else, so he probably wants to give a showdown of his talent before killing the target. But if he was afraid of Dumbledore, why did he need to duel him in a spectacular way in OotP instead of spamming killing curses everywhere ? And every other Death Eater should spam it too...

When the Death Eaters attacked Hogwarts, why did the Death Eaters not just use Avada Kedavra and kill everyone?


I am trying to build a class template that inherits the class. If the class template is given a primitive type as template argument, then it gives an illegal inheritance error. I tried doing  template <class Class_> struct EndianGuard_ : public Class_ {   EndianGuard_ () {     cout << "Guarding a Class" << endl;   } }  template <typename PrimitiveType_> struct EndianGuard_ {   EndianGuard_ (PrimitiveType_ Value) : Value(Value) {     cout << "Guarding a primitive type" << endl;   }   PrimitiveType_ Value; }   of course I knew it doesn't work that way but I am desperate. How can I differentiate primitive type and a structure?

I am looking for a way to identify primitives types in a template class definition.  I mean, having this class :  template<class T> class A{ void doWork(){    if(T isPrimitiveType())      doSomething();    else      doSomethingElse();  } private: T *t;  };   Is there is any way to "implement" isPrimitiveType().


I'm aware that Exchange supports opportunistic TLS (STARTTLS). But can I create a SMTPS receive connector (plain SSL)?

I am forced to use an old legacy system that apparently is never going away which requires an SSL/TLS connection but then transmits the information through the TLS tunnel plain text.  The most common thing I am finding for using TLS with exchange 2010 is to have a plain text connection and then use STARTTLS to begin encryption and send your message encrypted after the original plaintext connection.  Can someone help me de-cypher the settings inside exchange 2010's receive connector settings to accomplish this?


{     Random r = new Random();     int a = r.Next(1000000000);     string  Expirydate = txt_ExpirationDate.Text;      if (CryptoEngine.IsValidExpiration(Expirydate) == false)     {         Response.Write("<script>alert('Expiry Date not valid');</script>");     }  public bool IsValidExpiration(string ExpiryDate) {     string[] date = Regex.Split(txt_ExpirationDate.Text, "/");     string[] currentDate = Regex.Split(DateTime.Now.ToString("MM/yyyy"), "/");     int compareYears = string.Compare(date[1], currentDate[1]);     int compareMonths = string.Compare(date[0], currentDate[0]);      //if expiration date is in MM/YYYY format     if (Regex.Match(txt_ExpirationDate.Text, @"^\d{2}/\d{4}$").Success)     {         //if month is "01-12" and year starts with "20"         if (Regex.Match(date[0], @"^[0][1-9]|[1][0-2]$").Success)         {             //if expiration date is after current date             if ((compareYears == 1) || (compareYears == 0 && (compareMonths == 1)))             {                 return true;             }         }     }     return false; }   I am having error in the txt_ExpirationDate saying that      it doesn't exist in current context   I am also error at the CryptoEngine.IsValidExpiration saying that      an object reference is required for the non-static field

Consider:  namespace WindowsApplication1 {     public partial class Form1 : Form     {         public Form1()         {             InitializeComponent();         }          private void button1_Click(object sender, EventArgs e)         {             //int[] val = { 0, 0};             int val;             if (textBox1.Text == "")             {                 MessageBox.Show("Input any no");             }             else             {                 val = Convert.ToInt32(textBox1.Text);                 Thread ot1 = new Thread(new ParameterizedThreadStart(SumData));                 ot1.Start(val);             }         }          private static void ReadData(object state)         {             System.Windows.Forms.Application.Run();         }          void setTextboxText(int result)         {             if (this.InvokeRequired)             {                 this.Invoke(new IntDelegate(SetTextboxTextSafe), new object[] { result });             }             else             {                 SetTextboxTextSafe(result);             }         }          void SetTextboxTextSafe(int result)         {             label1.Text = result.ToString();         }          private static void SumData(object state)         {             int result;             //int[] icount = (int[])state;             int icount = (int)state;              for (int i = icount; i > 0; i--)             {                 result += i;                 System.Threading.Thread.Sleep(1000);             }             setTextboxText(result);         }          delegate void IntDelegate(int result);          private void button2_Click(object sender, EventArgs e)         {             Application.Exit();         }     } }   Why is this error occurring?     An object reference is required for the nonstatic field, method, or property 'WindowsApplication1.Form1.setTextboxText(int)


I'm a new Ubuntu user and I'm learning about how to install different software. I have installed Firefox browser successfully and now I want to install Chrome browser.  apt-cache search firefox - I used this command to search Firefox on the internet.  sudo apt install firefox - I used this command to install Firefox  I have searched on the internet for information about Chrome installation and I see it is a different way to install it.   I want to know why I can't install Chrome with the same commands used to install Firefox. Also, what is the best way to install Chrome with terminal commands?

Google Chrome is available for Ubuntu on the Google website but why is it not present in Ubuntu Software Centre?


As the title says, I am trying to insert into one table selecting values from another table and some default values.   INSERT INTO def (catid, title, page, publish)  (SELECT catid, title from abc),'page','yes')   INSERT INTO def (catid, title, page, publish)  VALUES ((SELECT catid, title from abc),'page','yes'))   The first query gives a mysql error and the second one gives column count does not match.   What do I need to do?

I'm trying to write a query that extracts and transforms data from a table and then insert those data into another table. Yes, this is a data warehousing query and I'm doing it in MS Access. So basically I want some query like this:  INSERT INTO Table2(LongIntColumn2, CurrencyColumn2) VALUES   (SELECT LongIntColumn1, Avg(CurrencyColumn) as CurrencyColumn1 FROM Table1 GROUP BY LongIntColumn1);   I tried but get a syntax error message.  What would you do if you want to do this?


Question: At a party $n$ people toss their hats into a pile in a closet. The hats are mixed up, and each person selects one at random. What is the expected number of people who select their own hats?  My Attempt: Note, $$E(X) = \sum_{s\in S} p(s)X(s)$$   $E(x)$ is the expected value. $p(s)$ is the probability of event $s$. $S$ is the sample space. $X(s)$ is the random variable.   The probability of one person picking his/her hat is $\dfrac{1}{n}$, two person picking their hat is $\dfrac{1}{n}\dfrac{1}{n-1}$. Let $n$ be the number of people, let $P(n, r)$ be number of $r-permutation$ in $elements$. to generalize,  $$p(s) = \dfrac{1}{P(n, s)}$$ where $s$, the sample is the number of people who picked their own hat.  Before I plug it all in to the $E(X)$ equation, the random variable is $X(s) = s$, or simply an identity function. My expected value formula is,  $$E(X) = \sum_{s\in S} \dfrac{1}{P(n, s)}*s$$  $$E(X) = \sum_{s=1}^{n} \dfrac{1}{P(n, s)}*s$$  Is this anywhere right? If I'm on track, how do I show what it equals to? The answer key said it should equal to one, but I'm lost from here.

The famous 'Hat Check Problem' goes like this, 'n' men enter the restaurant and put their hats at the reception. Each man gets a random hat back when going back after having dinner. The goal is to find the expected number of men who get their right hat back. To calculate the expected value from is definition, we have to compute the probability with which 'k' men would get their correct hat back.    How to compute this probablity? I know that this problem can be solved by using 'Linearity of Expectation' in a much simpler way, but i would like to know the way to compute this probablity.


I installed kali and the next day after coming to work I forgot the username, I was able to find answers on how to change the password but not to get username info.

I forgot my username in Kali Linux and can no longer login. Is there any way to view usernames?


I came across a head scratcher in my coding endeavors, and was wondering if anyone could give me some insight on it.  I have a header only class, that I was going to split into .h/.cpp, and while writing out the .cpp file, I noticed that I had no idea how to write methods for a nested class in a class template. Here's a code snippet (small part of what already runs):  namespace core {      namespace container {         template <class T>         class List { // the class          protected:             class Node {             public:                 T data;                 Node* next;                 inline Node(T d) : data(d),next(NULL) {}                 inline Node(T d,Node* n) : data(d),next(n) {}                 inline ~Node() {next = NULL;}             };         public:             // the rest of the class template, a here         };     }; };   The snippet is highly stripped down, with relevant stuff left behind. Normally, I don't deal with this as I tend to keep all my template stuff header-only, but compiling needs in other parts of the project would be smoother if I compile all this and hang on to the objects.  So initially I wrote  using namespace core::container; template <class T> List<T>::Node::Node(T d) {}   Now this isn't exactly the line, because I honestly don't intend on removing the inline constructor anyway, but I used it as an example because it's at the top of the code and simple.   I'm not sure if it was me or just that my IDE red-lined it, but it looked wrong to me. I'm away from my compiling machine so I can't run a test on it, and was wondering if I could get some insight before I write a few hundred incorrect lines.   So, am I doing this wrong? What is the proper way of defining a member function (or constructor in this example) for a subclass of a class template?

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


I know this will likely depend on different cultures. I am looking for that input.  Both my wife and I shower with our son - not all 3 a once, but one or the other accompanies him. Someone recently expressed the feeling (not a strong conviction) that it would be more appropriate for same sex showering to extend to this age and even beyond, but that Mother/Son showering didn't seem like a good idea after 5 or 6.  I had never even considered the notion that there might be something inappropriate in such co-showering. I recall my brother and I showering with my Dad until we were old enough to remember doing so - maybe 6 or 7. It never felt weird. But I have no recollections of bathing with my mother even though I know that I did so - so it must have stopped at an earlier age.  Am I in the minority? Should Mom/son co-showering be restricted/phased out sooner than Dad/son?    I don't believe this is a duplicate of  because I am trying to learn more about whether the genders involved would affect the age at which it would be inappropriate to shower together. Also, showering has a proximity and physical component that changing clothes or simply being naked doesn't.

Baby is 2 years 2 months old.  What will happen if we don't stop and at what age should we stop? Why?  From: What to Expect The Toddler Years (Arlene Eisenberg, Heidi Murkoff, Sandee Hathaway - 2009)     Even if a child doesn't show any such interest, family nudity could become a problem by age three, when it's believed that some children unconsciously become sexually stimulated by parental nudity, and are confused and embarrassed by these feelings. So it's probably wise to start donning bathrobes and segregating showers by your toddler's third birthday. You can explain such a change by saying, 'Now that you're older, you need to have some privacy, and so do I.'


Im starting a new big project with D7, so it will contains a lot of contrib / custom modules. It will be preferable to use the theme engine . What are the problems that could present later? anyone tried twig with D7 and have some big trouble using some of the contrib modules or any other further issues?

I do a lot of  development and I like their templating language. , the , looks very much like it.  How can I use Twig in Drupal 7 or even Drupal 6?


I'm trying to modify a script which emails a user group the contents of a directory. The modification I'm looking for is to check the script below to see if it has valid output before sending.  The script is:  cd $foo/bar && ls | mail -s "Filenames in the \$foo/bar Directory" john.smith@who.com  I want to test if the file is null before sending this email, as this will go on three dozen servers and many to the same person/people, so I don't want to send a bunch of blank emails (which is the status quo).  I have looked at other similar questions, but none of them quite scratch the itch. This one is closest:    but is for a file attached, which won't work. Also, man mail returns a -E flag that is supposed to perform the content check, but I've played with it and my version doesn't seem to support the -E option (which is not something that can readily be changed). I get an error mail: invalid option -- E.  Any help would be appreciated. It doesn't have to be a one liner, but that sure would help!  EDIT - I need the directories to be dismissed in the output check, if this is possible! I did not clarify this originally, but if $foo/bar has a directory of /errors can this be avoided?

How can I rewrite this command to only email if there is output from the mailq | grep?  mailq | egrep 'rejected|refused' -A 5 -B 5 | mail -s 'dd' email@email   Is this even possible on one line?  See  for a more general case than sending email.


First time I've ever needed to ask a question here that I don't think has already been answered.  I've recently been working on transferring over a vBulletin site I run to a new server. Thinking that I was being all ahead of the curve, when I went to install Ubuntu on it recently and saw 14.04 was available, I went for it.  As I should have expected, it's a nightmare. Turns out that vBulletin JUST added support for PHP 5.4 with their last release on the version I run. I honestly don't expect them to ever get it up to PHP 5.5 (what 14.04 installs by default).  Save from going back to 12.04 LTS and starting completely over, is there a way I can downgrade the PHP version installed to 5.4? I saw some threads talking about this for going from 5.4 to 5.3, so I'm hoping its doable.  The simpler you can help me to do this, if possible, the better. I know my way around, but by no means consider myself an expert. Thanks!  EDIT: For clarity. Need to downgrade PHP from 5.5 to 5.4 on 14.04 (Trusty Tahr).

I am trying to update to install PHP 5.5, 5.6 or 7.0 in Ubuntu 12.04/14.04/16.04 LTS, and I can only get PHP 5.3.10 for Ubuntu 12.04, PHP 5.5.9 for Ubuntu 14.04 or PHP 7.0.4 for Ubuntu 16.04 using official repositories (using apt-get).  I'm not really sure how to do a manual update – as I need:   to play around with the new(est) PHP features to install older PHP version due support in the software


I recently migrated some sites from my old server to a new one with the same configuration on DigitalOcean.  The sites working great except for the php mail() function that isn't sending emails.  The php configuration is the same of the old server, and I can't see where the problem is.  The postfix configuration is:  $ postconf -n alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases command_directory = /usr/sbin config_directory = /etc/postfix daemon_directory = /usr/libexec/postfix data_directory = /var/lib/postfix debug_peer_level = 2 html_directory = no inet_interfaces = localhost inet_protocols = ipv4 mail_owner = postfix mailq_path = /usr/bin/mailq.postfix manpage_directory = /usr/share/man mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain mydomain = MY_DOMAIN myhostname = MY_DOMAIN myorigin = $mydomain newaliases_path = /usr/bin/newaliases.postfix queue_directory = /var/spool/postfix readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES sample_directory = /usr/share/doc/postfix-2.6.6/samples sendmail_path = /usr/sbin/sendmail.postfix setgid_group = postdrop unknown_local_recipient_reject_code = 550   And when a make a test, the maillog output is:   Jun  3 16:43:18 tori postfix/pickup[3648]: 7F6D8480E73: uid=500 from=<santiago@gmail.com> Jun  3 16:43:18 tori postfix/cleanup[4033]: 7F6D8480E73: message-id=<20150603204318.7F6D8480E73@MY_DOMAIN> Jun  3 16:43:18 tori postfix/qmgr[3649]: 7F6D8480E73: from=<santiago@gmail.com>, size=360, nrcpt=1 (queue active) Jun  3 16:43:18 tori postfix/error[3992]: 7F6D8480E73: to=<santiago@gmail.com>, relay=none, delay=0.06, delays=0.05/0/0/0.01, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to aspmx5.googlemail.com[74.125.205.27]:25: Connection timed out)   Can you help me?  Thanks.

I used the  tutorial below to setup postfix and dovecot on a Digital Ocean server. But I'm getting "Connection Timed out" when postfix/smtp tries to deliver an email to a remote host like gmail or yahoo..      RECEIVING A NEW MESSAGE /var/log/mail.log    Feb 2 22:33:38 localhost dovecot: auth-worker: Debug: Loading modules from directory: /usr/lib/dovecot/modules/auth  Feb 2 22:33:38 localhost dovecot: auth-worker: Debug: pam(app,189.63.49.XXX): lookup service=dovecot  Feb 2 22:33:38 localhost dovecot: auth-worker: Debug: pam(app,189.63.49.XXX): #1/1 style=1 msg=Password:   Feb 2 22:33:38 localhost dovecot: auth: Debug: client out: OK#0111#011user=app  Feb 2 22:33:40 localhost postfix/submission/smtpd[1045]: E9AA724264: client=unknown[189.63.49.XXX], sasl_method=PLAIN, sasl_username=app  Feb 2 22:33:43 localhost postfix/cleanup[1052]: E9AA724264: message-id=  Feb 2 22:33:43 localhost postfix/qmgr[32661]: E9AA724264: from=, size=485, nrcpt=1 (queue active)  Feb 2 22:33:45 localhost postfix/submission/smtpd[1045]: disconnect from unknown[189.63.49.XXX]  Feb 2 22:34:14 localhost postfix/smtp[1053]: connect to mta5.am0.yahoodns.net[98.136.216.25]:25: Connection timed out    Feb 2 22:24:21 localhost postfix/smtp[1013]: connect to mta6.am0.yahoodns.net[98.136.217.202]:25: Connection timed out  Feb 2 22:24:21 localhost postfix/smtp[1014]: connect to gmail-smtp-in.l.google.com[173.194.76.27]:25: Connection timed out  Feb 2 22:24:21 localhost postfix/smtp[1015]: connect to gmail-smtp-in.l.google.com[173.194.76.27]:25: Connection timed out  Feb 2 22:24:21 localhost postfix/smtp[1012]: connect to aspmx.l.google.com[173.194.68.27]:25: Connection timed out    Here is /etc/postfix/main.cf   /etc/postfix/master.cf   Result from #> netstat -nlptu


Will I be able to reenter the United States from Mexico using CBX if I don't have my passport card, yet? I have dual citizenship and am leaving to Mexico soon. Will I be able to use other documentation ie id card, social, copy of citizenship, passport receipt? Pls help.

I am an American citizen born in the United States. I am in Mexico at present.  Can I use my birth certificate and drivers license to cross the border by foot if I don't have a passport?


Here is the problem If $c\ |\ ab$ and $\text{gcd}(a,c)=1$ then $c\ |\ b$ Here's my approach. There exists $x,y$ such that $ax+cy=1$, so $c\ |\ axb+cyb=b$ I'm pretty sure my first step is wrong. Any help would be appreciated!

Let $A$ be a UFD. Assume that $a,b \in A$ are relatively prime, $c \in A$ and $a | bc$. To prove that $a|c$, is the following approach correct (or do you have to use some type of prime factorization argument)?  By the relatively prime assumption, $\gcd(a,b)$ is a unit. Call that unit $u \in A^{\times}$. Then we can write $u = ax + by$ for some $x,y \in A$. But then, $c = c \cdot u = c(ax+by)=cax+cby$. However, it is clear that $a|cax$ and the fact that $a|bc$ implies $a|cby$. Thus, $a|cax+cby=c$.


I need to convert the array to an array list and am not sure how to do this, I have looked at other articles on here and couldn't seem to get it to work, if anyone could provide me with some pointers as and to how to convert this to an array list that would be fab.   import java.util.*;   public class SearchExamResults  {     public static void main(String[] args)     {         Result[] resultsArray = new Result[20];          input(resultsArray);         sortByMark(resultsArray);         output(resultsArray);     }      public static void input(Result[] array)     {         Scanner kybd = new Scanner(System.in);         for (int i = 0; i < array.length; i++)         {             System.out.println("Candidate " + (i + 1));             System.out.print("\tName: ");             String name = kybd.nextLine();             System.out.print("\tMark: ");             int mark = kybd.nextInt();             kybd.nextLine();            //to flush the kybd buffer              array[i] = new Result(name, mark);         }     }      public static void sortByMark(Result[] array)     {         //selection sort         for (int pass = 1; pass < array.length; pass++)         {             int lastElement = array.length - pass;             int largePos = findLargestMark(array, array.length - pass);             if (largePos != array.length - pass)             {                 Result temp = array[largePos];                 array[largePos] = array[lastElement];                 array[lastElement] = temp;             }             //this is for testing purposes only             //output(arr);          }     }      public static int findLargestMark(Result[] array, int last)     {         int largestPos = 0;         for (int i = 1; i <= last; i++)         {             if (array[i].getMark() > array[largestPos].getMark())             {                 largestPos = i;             }         }         return largestPos;     }      public static void output(Result[] array)     {         System.out.println("\nExam results");         System.out.println("============");          for (int i = 0; i < array.length; i++)         {             System.out.printf("\t%-20s\t%d\n", array[i].getName(), array[i].getMark());         }     }  }

I have an array that is initialized like:  Element[] array = {new Element(1), new Element(2), new Element(3)};   I would like to convert this array into an object of the  class.  ArrayList<Element> arraylist = ???;


So, long time ago I got a malware from a pendrive, it cloned a directoy on my system32 folder and attempted to do bitcoin mining on my pc. After that, every new pendrive connected to my pc would also get the folder copied from my system32 to the pendrive. So after I found the source, I deleted the directory and every registry about it from regedit, and it worked fine. There's only one thing missing, everytime I turn out the computer a Windows Script Host error would show up saying "Cannot find file C:\system\system.vbs" (which was in the folder I purged) and even after I close it, it would show up again, so that means there's still the process that tries to execute that vbs.  Is there a way to find the source of the windows script host error? Or the process that's executing it?  So I can 100% purge this malicious thing at last

I'm trying to delay the startup of a specific program that loads at login. As per an answer in , I should be able to do it using Task Scheduler. The problem is, I can't find the program listed anywhere. Is there a particular pane I should be looking in? The program is Razer Synapse so I don't think it would be in the Microsoft or Western Digital folders.    If it's not in Task Scheduler, is there another way I can delay it at startup?  Out of curiosity how many ways are there for a program to be run at Startup in Windows?


I was reading a book of linear algebra and started the chapter of isomorphisms. The book describes them as linear maps that are injective and surjective. Then I realised that that condition is the same as invertibility of the matrix of the linear map, but I don't know how to prove it. So, my idea is: Given a linear map $f: E\to F$ (with $dim(F) = dim(E)$ and basis $B$ of $E$ and $B'$ of $F$, I want to proof that $f$ is an isomorphism if and only if it is invertible. That is, I want to prove they are equivalent. In some way I kind of "feel" it, but don't know how to proceed. Here is my attempt for the right-to-left implication: we assume $f$ is invertible. Then we want to show it is injective and surjective. Let $u,v \in E$, and $f(u) = f(v)$, then $u = f^{-1}(f(u)) = f^{-1}(f(v)) = v$, therefore $f$ is injective. To prove it is surjective we want to prove that $range(f) = F$. Let $w \in F$, then take $v = f^{-1}(w)$, the existance and uniqueness of this element is guaranteed by the invertibility of the inverse of $f$. Then $f(v) = f(f^{-1}(w)) = w$. So $range(f) = F$. However, for the other direction I don't know how to do it. Can somebody help me?

To have an inverse, a function must be injective i.e one-one.  Now, I believe the function must be surjective i.e. onto, to have an inverse, since if it is not surjective, the function's inverse's domain will have some elements left out which are not mapped to any element in the range of the function's inverse.   So is it true that all functions that have an inverse must be bijective?   Thank you.


I have a procedure in Delphi which currently looks like this:  Procedure Time.TimeDB(algorithm: string; Encode, Decode: InputFunction; N, R: Int); VAR     i : LongInt;     Errors : Array[N] of LongInt; BEGIN  for i := 0 to N-1 do   Errors[i] := 0;  END;   I'm given the error that N, as passed to the definition of Errors, is an undeclared identifier, despite declaring it in the procedure definition. N is recognised in the BEGIN-END section though. Any ideas what's causing this and how I can otherwise declare a variable-length array in the VAR section?

I originally had an array[1..1000] that was defined as a global variable. But now I need that to be n, not 1000 and I don't find out n until later. I know what n is before I fill the array up but I need it to be global therefore need a way to define the size of a global array at run time.  Context is filling an array with a linear transformation of the bytes in a file.  I don't know how big the file is until someone wants to open it and the files can be of any size.


I was recently looking at my network profile, and one of my PPCG questions, , was listed as 5 votes.  However, when I clicked the link, here is the result:       Simple math says that 9 - 3 = 6, 6 =/= 5. Don't tell me this is caching, because the question was last upvoted on May 27.

Noticed in :         is 320, shown 322. Also locked in 2013.  And then :         has a score of 179, shown 180.  has a score of 123, shown 122.  Neither of these posts got any votes recently.


I am trying to right a program, with arrays, which gets random numbers between 0 - 24 but they can only occur once. I know how to generate random numbers, I am just stuck on how to do the check to see if the number already exists in the array. I tried generating a new rand() % 25 and comparing it with placeholders in the array and if it didn't exist put the new random number in there but it did not work.   void MultiU (){          int size = 5;          int array[5];         srand(time(0));          for (int index = 0; index < size; index++){            exists[index] = rand() %25;           }     }   I am new to programming with arrays and rand(). I hope someone can guide me in the right direction.

I'd like to generate unique random numbers between 0 and 1000 that never repeat (i.e. 6 doesn't show up twice), but that doesn't resort to something like an O(N) search of previous values to do it. Is this possible?


I am trying to view my model in Blender and I would like to change the controls a bit. Right now, when I press down on my scroll wheel (middle click), and then move my mouse left-to-right, I am rotating my view of the model about the Z-axis of the blender-model world frame. When I middle-click and push the mouse up-and-down, I am rotating my view about the view-matrix X-axis (the X-axis if this were an OpenGL window). In other words, it looks as if I am at the top of a hill and I push the blender model down the hill. What I would really like to have happen when I middle click and drag sideways is to have the blender model rotate about the view-matrix Y-Axis, like you would on a trackball-style mouse. In other words, if I push the model "down a hill", I have a birds-eye-view of the model rolling down the hill. How do I change the layout model viewing rotation behavior as described? This looks like what I , but it is a really old answer. Is there an updated version of this? I use blender 2.90.X

What I want to do while modeling is start at the Top Ortho view (NumPad 7) with green Y-axis pointed up and down on the screen. I then want to rotate the view left or right around my model, moving only the X & Z axis' while keeping the Y-axis vertical.    Ctrl Shift MMB  zooms the view in and out if the wheel is held down and the mouse moved. If the wheel is scrolled the view rotates around the Z-axis. Going to view 3 and Alt Shift MMB  allows rotating around a Horizontal Y-axis.  Is there a way to rotate around a vertical Y-axis?


I am receiving a null pointer exception and I am not sure why. I have this function that is called when a button is pressed:  @FXML private void handlePlayButton(ActionEvent e) {      for(Node child:getCenterPaneUndirectedNonWeightedGraph().getChildren()) {         if(child instanceof StackPane) {             StackPane vertex = (StackPane) child;             System.out.println(vertex == null);             bfs.fillVertexTransition(vertex);         }     }  }   My print statement 'System.out.println(vertex == null);' prints false.  I get the null pointer exception at the line:  bfs.fillVertexTransition(vertex);   The method 'fillVertexTransition' is defined by:  public void fillVertexTransition(StackPane vertex) {     Circle circle = (Circle) vertex.getChildren().get(0);      FillTransition ft = new FillTransition(Duration.millis(3000), circle, Color.RED, Color.BLUE);     ft.play();  }     In my application the StackPanes are circles with a label on top of the circle.  Any way I can fix this?  Thank you.

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


It would be nice to have a program which I can use to do some drawing/sketching in a .pdf document and I can also scroll up or down.  Like this:    (Edited with GIMP)  It is not necessary to save the documents with the sketch.  Is there any program that can do these?

I'm used to OS X where the system PDF viewer will let you draw and write text on top of any PDF document. You can then flatten it and save as a new PDF. It saves paper and time so you can fill in any form without printing it and scanning it back to the computer.  It also lets you insert a scanned image of your signature.  Is there software for Ubuntu that would do that?


I have the series $\sum_{i=1}^\infty n^n/n!$ in my math textbook, and it is used as an example for the ratio test. Completing the ratio test on this problem leads to having to take the limit of:  $$\lim_{n \to \infty}(1+1/n)^n$$  the textbook says that the answer is $e$, however when I take the limit I get  $$ (1+1/\infty)^\infty $$ which is just $1^\infty = 1$.     Am I missing something as to why this is not $1$? Does the variable $n$ behave different from other variables?

On Wikipedia, it says that $\lim_{n\to\infty}(1+\frac{1}{n})^n = e$ :     It [e] is approximately equal to 2.71828,[1] and is the limit of (1 + 1/n)n as n approaches infinity, ... ()   When I evaluate $(1+\frac{1}{n})^n$ for $n = 10^8$, I get approximately $2.718281798347$ which indeed is pretty close to $e$.  But when I try to "solve" the limit using the laws of limits, I get  $$\lim_{n\to\infty}\left(1+\frac{1}{n}\right)^n = \left(\lim_{n\to\infty}\left(1+\frac{1}{n}\right)\right)^n$$  because of the power law  $$ = \left(\lim_{n\to\infty}(1)+\lim_{n\to\infty}\left(\frac{1}{n}\right)\right)^n$$  because of the addition law  $$=\left(1+0\right)^n = 1$$  but that would mean that $e=1$, which is obviously not true.  What am I missing / doing wrong?  Thanks in advance.


Python newbie here. I've used XPath to extract some data from a website which gives me a list in a list that looks like this: [['1','2','3'],['4','','6'],['7','8','9']] Currently, when I export this to CSV, each of the 'inner' lists is displayed in a single cell like: Cell A1 ['1', '2', '3']) Cell B1 ['4', '', '6'] Cell C1 ['7', '8', '9'] which means I would have to remove the unwanted brackets and quotes, Text-to-Columns and transpose to get what I want, which is this: 1,4,7 2,,8 3,6,9  What can I do/use to do this?

I have a list of 2-item tuples and I'd like to convert them to 2 lists where the first contains the first item in each tuple and the second list holds the second item.  For example:  original = [('a', 1), ('b', 2), ('c', 3), ('d', 4)] # and I want to become... result = (['a', 'b', 'c', 'd'], [1, 2, 3, 4])   Is there a builtin function that does that?


I want to resize this part:   I installed Ubuntu 16.04 and I want to resize this and give an empty memory so that I can install Windows 10. However, I can't resize it and don't know why.

Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers.  Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions).  Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space.  How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions?


I recently started using Grammarly in some of my writing and the spell/grammar checking software seems to place a comma after just about all conjunctions. I thought that a conjunction was, sort of, like a comma in a sentence, that is, it separates a thought. So, the question is, is there some rule for when it is proper to use both a conjunction AND a comma?

This is a bit of a strange question because I know that there should never ever be a comma after 'and.' But what if there's a parenthetical statement/clause-thing right after it? Let me demonstrate.      She spread her arms, tilted her head back, and, closing her eyes, let the sun warm her face.    Should it be:      She spread her arms, tilted her head back, and closing her eyes, let the sun warm her face.    I feel like the ,and, looks really bulky, but I also feel it's necessary to separate the statement between the commas. Help?


Does entanglement not immediately contradict the theory of special relativity? Why are people still so convinced nothing can travel faster than light when we are perfectly aware of something that does?

From everything I've read about quantum mechanics and quantum entanglement phenomena, it's not obvious to me why quantum entanglement is considered to be an active link. That is, it's stated every time that measurement of one particle affects the other.  In my head, there is a less magic explanation: the entangling measurement affects both particles in a way which makes their states identical, though unknown. In this case measuring one particle will reveal information about state of the other, but without a magical instant modification of remote entangled particle.  Obviously, I'm not the only one who had this idea. What are the problems associated with this view, and why is the magic view preferred?


Given a group $G$, let $G_m$ be the group generated by the set $S=\{g^m|g\in G\}$.  Prove that if $G_m$ and $G_n$ are both abelian, then $G_{\gcd(m,n)}$ is also abelian.

Let $(G,.)$ be a group and $m,n \in\mathbb Z$ such that $\gcd(m,n)=1$. Assume that $$ \forall a,b \in G, \,a^mb^m=b^ma^m,$$ $$\forall a,b \in G, \, a^nb^n=b^na^n.$$  Then how prove $G$ is an abelian group?  Some context: Some of these commutation relations often imply that $G$ is abelian, for example , or . This looks like another example of this phenomenon, but the same techniques do not apply.


I have inherited a SQL Server 2008 R2 (SP3) Database. There are backups being taken daily at seemingly random times. The backups are not being saved locally on the server. I see the backup information in msdb..backupset table. What is taking these backups and where is it storing these backups? I see that VSS writer is the program name, I can disable the Service but I would like to get more information of what was done before I disable this service.   There are no agent jobs There don't seem to be any Task Scheduler Jobs There is no external program installed   I have created a trace and I see the following.  SQL: BACKUP DATABASE [master] TO VIRTUAL_DEVICE='{8305D2E8-56C5-41E5-9F54-    17DDEE1A6991}7' WITH SNAPSHOT,BUFFERCOUNT=1,BLOCKSIZE=1024,COPY_ONLY  HostName is same as Server  Application Name: Microsoft SQL Server VSS Writer  LoginName: NT AUTHORITY\SYSTEM

We have an instance of SQL Server 2008 installed on a customer server. The customer's IT department is in charge of the various backups of the machine.  The SQL Server log shows there is a full backup every day at 7 PM but we can't find evidence of any plan scheduled in SQL Server.  The technicians we contacted couldn't tell us if there was some sort of automatic backup, all they told is that the entire machine is being backup up.  Using a script I found in  I found out that the physical device name is a GUID and that this means that this is an external backup process:  USE [msdb] GO  SELECT      [bs].[database_name],      [bs].[backup_start_date],      [bs].[backup_finish_date],      [bs].Server_name,     [bs].user_name AS [BackupCreator] ,     [bmf].physical_device_name FROM msdb..backupset bs   INNER JOIN msdb..backupmediafamily bmf ON [bs].[media_set_id] = [bmf].[media_set_id]  ORDER BY [bs].[backup_start_date] DESC   This is a row from the above query:     db_name 2015-09-16 19:01:23.000   2015-09-16 19:01:28.000SERVER_NAME  NT AUTHORITY\SYSTEM{424F084A-F35D-4A66-8FC7-072268A89A77} 5   Moreover the backup start and finish date spans only for 5 seconds, so I guess it's clear it's not a job of sql server.  This is a line from the log:     2015-09-03 19:02:30.71 Backup   Database backed up.   Database: db_name, creation date(time): 2012/10/12(20:52:11), pages dumped: 3290021,   first LSN: 276028:152755:172, last LSN: 276028:152827:1, number of dump devices: 1,   device information:   (FILE=1, TYPE=VIRTUAL_DEVICE: {'{95380B0A-D50B-408F-B95F-1AB8975BA7F8}5'}).   This is an informational message only. No user action is required.   So, since they can't help us what can I do to track down the process responsible of the backups? We need this because we want to coordinate the backup in an ordered manner, and do the transaction log backups too in order to keep the log at a reasonable size (now we do shrink the log every week, and this is not the good way to go).


My Dell XPSl521x is very warm. The temperature sometimes reaches 90°C. Psensor shows that the laptop is hot: it has a red colour.  What should I do?

Don't Know why my PC heats up while i use ubuntu (any version). I have dell i7 processor system with 1 GB nvidia. Still finding solution but no positive and effective solution found. any suggestion


I have a folder with 20000 files in it. I need to split it into subfolders with increasing directory name (dir_1, dir_2....) with each folder having 500 files each in such a way that for example if files are from file_1.png to file_20000, the first folder should contain first 500 files i.e., file_1 to file 500 and immediate folder should contain files in a continued manner i.e, file_501 to file_1000 and so on.

I have around 100,000 files in a directory. As you can imagine, that's not an ideal situation, and I'd like to split the directory up into subdirectories. But the filenames aren't such where I can put them into subdirectories based on their names or anything, so I'd like to create, say, 10 directories and put about 1000 files in each. Is there an easy bash command or loop that would do this?


From :  Leicester City Football Club, whose entire squad cost less than a single player at some of its better-known rivals, have won the English Premier League. Leicester were 5000-1 outsiders to win at the start of the season, meaning bookmakers considered it more likely that Elvis Presley would be found alive.  Don't understand why "5000-1 outsiders" instead of "5000-1 outsider".

I'd say Microsoft have a way of bending the rules and I know that McLaren have won the championship. While this sounds strange, I believe it is correct English (sorry, I'm not native).   But when it's a small company, would you still use it this way? Is a company always plural, or are small companies singular? I.e., would you say Bakery Johnson makes fine bread or Bakery Johnson make fine bread? Is it My book seller, Woody's, have moved or is it has moved?


Now that LIGO has demonstrated that two black holes can burp large amounts of energy (in the form of gravitational radiation) in the process of consuming each other, shouldn't we stop saying that nothing can escape the event horizon of a black hole.  Clearly, some of the mass energy that was observed in the LIGO experiment was confined by the event horizons of the two black holes prior to their merger.  Somehow, in the transition from two separate event horizons to a single event horizon there was opened an escape route (if only for a short time).  I realize that Hawking radiation allows an evaporation of energy from a black hole, but that is a very slow process.  Unless I am mistaken, LIGO-like events provide an avenue for prompt release of large amounts of energy.

BH mass is a conserved quantity and cannot escape the horizon of a BH. Yet in mergers some percent (in GW150914 it was about 5 percent, or 3 solar masses) of the binary's mass escaped either before (one of the two BHs horizons) or after the merger started (one horizon merger, from the merged horizons), and turned into gravitational waves. The argument is that it is potential energy or maybe kinetic energy of the black holes that is radiated. It does not matter. The question is how did the BHs mass get reduced? Did some virtual negative mass particles fall into the BH, and if so it would have been gravitons? If so is it a quantum effects? If so has anyone worked out the linearized quantum gravity of that happening right outside the horizons, like they did for the very small Hawkings radiation, and isn't that a contradiction of the small effects expected for 30times solar mass BHs? So, if not that, how does the negative potential binding mutual gravitational energy of the two BHs steal mass from the binaries?  Please, no hand waving. I've looked everywhere and only see hand waving arguments about potential or other energy outside the BHs, but mass is an internal (inside the horizons) and conserved quantity of BHs.   Charge, another conserved quantity, and angular momentum, can be extracted (i.e., escape the EH). Angular momentum through the Penrose process, maybe charge too. Is it the same for mass? If so, where is it wel explained in some detail, and not simply 'it was calculated numerically'?


Example: If you install two apps using Island (), do the two apps able to see each other, meaning that one can see another data?

I confess that I come from the happy world of unix computers, and am used to the concept of user accounts and hence group gids and userids uids. For the occasional usage of an untrusted app (i.e. whatsapp/facebook) I have created another user profile for many reasons, but mostly because I wanted to reduce any potential access whatsapp/facebook might gain with regards to my main account.  Now the strange thing is that to the best of my understanding the protection mechanism of AOSP, relies on assigning a actually user ids to individual apps, as with those uid, the apps can be limited using that the underlying linux kernel provides Unix Discretionary Access Controls (i.e. file accesss dependent on uid and gid).  My question is if I am misleading myself that AOSP provides any stronger protection with regards to multi-users (in between the accounts) than it does with regards to the various apps to each other?


What is the effect of the birthday bound on the security of AES-GCM, when a very large number of messages are encrypted?  I am looking for attacks that are useful in obtaining information about the plaintext and/or creating forgeries, not just distinguishers.

In a  a doubt was voiced about my answer, which claims GCM to requires $2^{128}$ for a successful forgery. The doubt was that the square root needs to be taken meaning the security would be $2^{64}$.  So of course I immediately checked the relevant security theorem ():  $$\mathbf{Adv}^{\text{auth}}_{\operatorname{GCM}[\operatorname{Perm}(n),\tau]}(\mathcal A)\leq \frac{0.5(\sigma+q+q'+1)^2}{2^n}+\frac{q'(\ell_A+1)}{2^\tau}$$  with $\sigma$ being the total plaintext size in blocks, $q$ being the total number of encryption queries, $q'$ being the total number of decryption queries, $n$ being the size in bits of the underlying permutation, $\ell_A$ being maximum authenticated input length in blocks and $\tau$ being the tag size in bits.  Now clearly from this we can see that performing $2^{n/2}=2^{64}$ queries yields a strong enough advantage for a break.  Now my question is: When talking about "n-bits of security" or "needs $2^n$ operations to break", do we usually talk about "online" security, ie queries to an oracle can be done and cost $1$ or "offline" security where no oracles are available or do we need to make this decision depending on the situation?  TL;DR: Does GCM offer 64 or 128 bit security?


Hi people I just need a quick fix on how to do the validation for this question. Unfortunately the book I am using doesnt seem to provide a solution after attempting the program. Here is the the question.  "Write an input validation program that asks the user to enter 'Y', 'y' 'N' or 'n' "  keep in mind it must be done only using a while loop any help would be appreciated.  while(answer != "y" || answer!= "n" )     {         System.out.println("Please use a  Y or N");             answer = keyboard.nextLine();     }   that is my current loop but it doesnt seem to work even if i enter y or n in it.  The current output i keep getting is "Please use a  Y or N" regardless if I enter the correct letter

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


When I make a new .tex document, three other files are created as well, .pdf, .aux and .synctex. I want the .pdf file, but are the other two necessary, can I delete them? Can I tell latex to not create .aux and .synctex files?

Is there a way to make TeX delete files?   In my document a lot of auxiliary files are created and it would be wonderful to have them removed after their content has been used.


If $G$ is a graph with at least one cut-vertex, then at least $2$ of the blocks of $G$ contain exactly $1$ cut-vertex. To illustrate, I have this example:  A simpler example would be to consider two cycles with a common vertex, we can see that it is a cutting vertex and has only two blocks, since each pair of vertices is in a common cycle.

A graph which is not a single block has at least two leaf blocks.    According to the Intro. to Graph Theory by D. West:    Block: A maximal connected subgraph of $G$ that has no cut-vertex. Leaf block: A block that contains eactly one cut-vertex of $G$.   I have not well understood this statement. Would you elaborate on this statement.   Edit: Can we say this:      The block-cutpoint graph of a connected graph is a tree where its leaves denote the blocks of $G$. Since a tree has at least two leaf blocks hence the graph has at least two leaf blocks if it is not a single block.


The spelling of number is number, but the abbreviation is No (№). There is no letter o in number, so where does this spelling come from?

Why the disparity? And why use 'No.'? Is it from the French?  And the hash or pound sign seems a weird choice too, is there a history or any reason involved?


Which of the following sentences is correct:        There is a lot of food and fruit in the supermarket.   There are a lot of food and fruit in the supermarket.

I want to write that I have handful of somethings.  Which of these is the correct form?   There is a handful of somethings. There are a handful of somethings.   Are both correct?


When I am trying Ubuntu from an USB drive, can I save my work? Is it possible to keep installed software and configs for the next session?

I want to make a persistent live Ubuntu USB drive with more than 4GB of storage.   I know there is an option of installing directly on the drive but I don't want to do this as it will restrict the drive from working on different computers.   One option is to make an additional partition with extra space but if I do this how can I get newly installed software to be stored on this partition?


How to write a password which contain "&" in app.config  <add connectionString="Data Source=x.x.x.x;Initial Catalog=Testing002;User Id=hello;Password=&a:;" name="ConString"/>

I've got a C# program with values in a config file.  What I want is to store ampersands for an url value like...  <appSettings>   <add key="myurl" value="http://www.myurl.com?&cid=&sid="/> </appSettings>   But I get errors building my site.  The ampersand is not allowed.  I've tried various forms of escaping the ampersands to no avail.  Anyone know of the correct form to do this?  All suggestions are welcome.


I think the exit row near the wings are not good because the wings carry fuel and they are close to the engines.  For example:    As it is clear, in the above situation the exit row near the wings are not usable.  or this one:

So to clarify, there are lots of different planes, so for the sake of argument, there are areas:   front left front right front middle forward front, right, middle over the left wing over the right wing middle, between the wings mid-way back, left, right, or middle at the back left, right, or middle pilot seat co-pilot seat jump-seat, if it exists   So that's 18ish possible safe zones in the plane.  Is there a particular area that statistically people have survived more (or less) in?


We know that if F is a field, then the polynomial ring over F is a PID. Do you have a counterexample that shows that if F isn’t a field than the polynomial ring over F isn’t a PID?

Wikipedia says that a commutative ring $A$ is a field iff $A[x]$ is a PID.    The "only if" part is easy: we just apply the Euclidean algorithm. I've stumbled trying to prove the "if" part, though.  $\newcommand{\aa}{\mathfrak{a}}$ My best attempt so far: suppose $\aa$ is an ideal of $A$, and $\aa'$ is the ideal of $A[x]$ spanned by $i(\aa)$, where $i: A \hookrightarrow A[x]$ is the natural embedding. $i^{-1}(\aa') = \aa$ for grading reasons ($i(A) = A[x]^0$, and multiplication by a non-zero degree polynomial takes us out of $i(A)$, because $A \cong i(A)$ is integral). $A[x]$ is a PID so $\aa' = (a')$, where $a' = i(a)$ for some $a \in A$. Therefore, $\aa = (a)$, and thus $A$ is also a PID.  That's the best way to use the fact that $A[x]$ is a PID that I've found so far. Now I feel like there must be a trick to show that if $a \neq 0$ then $a = 1$, but I don't know how to do this. Any hints?


I'm trying to dual boot Ubuntu 13.10 along with Win8.1. The problem here is Ubuntu installer does not recognize any of my partitions and shows my whole hdd space as unallocated. That is the case with GParted also. The tricky part is that the Ubuntu itself (in Live mode) is perfectly capable of recognizing and mounting the partitions.  I did a little searching and came up with  but I can not be sure that it applies to my problem too as I can not risk loosing my Windows installation.  UPDATE: The result of mount:  /dev/sda2 on /media/ubuntu/585084B850849DFE type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096) /dev/sda3 on /media/ubuntu/Linux type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096) /dev/sda5 on /media/ubuntu/Linux Home type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096) /dev/sda6 on /media/ubuntu/Misc type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096)   UPDATE 2: Upong running GParted I get the following message:     /dev/sda contains GPT signatures, indicating that it has a GPT table.    However, it does not have a valid fake msdos partition table, as it   should.  Perhaps it was corrupted -- possibly by a program that   doesn't understand GPT partition tables.  Or perhaps you deleted the   GPT table, and are now using an msdos partition table.  Is this a GPT   partition table?   And here is a screenshot from GParted.

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


System: Ubuntu 11.04, regular user account:     find /usr/share -name *.wav   works okay, but if i do:     find /usr/share -name *.png   it does not produce any output  How do i change the last command to produce an output, like the first command did?

I can't for the life of me figure out how find with the test -name works.  I run find / -name *in and returns a bunch of results:  /sbin /sbin/sulogin /dev/stdin   to name a few.  It's as if it performed filename expansion, but that happens before the shell runs the command, so that can't be it. Also because I don't have any files in the current directory that match *in. Plus, single quoting *in yields the same results, which further supports that this can't be filename expansion.  The documentation leads me to believe that find with -name uses regular expressions, but the regex pattern *in doesn't match the results I showed above.  Can someone enlighten me?


Around 1980/81, a car-pool buddy told me of a story that he had read about a computer virus that constantly evolving.  I vaguely remember that it's human programmer had created several early variants that weren't self-sustaining but as they 'died' he would add new characteristics - self-replicating, mirror real code to escape detection, and eventually self-modifying so it could learn and adapt on its own.  I don't remember the title or author (or friend, for that matter) but it was the earliest I had heard of a computer virus that evolved.  Any thoughts?

This book came out of the 1970s (early 1980's) at the latest. In it the protagonist, a not so diligent student, gets turned on to computer programming and creates (I think..) a weather program.   Eventually he moves on and years later the program contacts him. It has become an AI and he is its creator.  I forget what the setup is post contact which is not helpful at all..


I figure it has something to do with minimal polynomials and the Jordan canonical form, I just can't piece it together. I would really appreciate a hint on how to start it.

$A$ is a $n\times n$ matrix such that $ A^m = 0 $ for some positive integer $m$.   Show that $A^n = 0$.   My attempt: For $n > m$, it's obvious since matrix multiplication is associative.  For $n < m$, $A^n\times A^{m-n} = 0$; not sure what to do next. Also I know that $\det A = 0$.


I have the following equation:  \begin{align} \frac{1}{4}\left[\frac{\partial{(u^n+u^*)(u^n+u^*)}}{\partial{x}}\right]_p  &=\nonumber\\ \dfrac{u_{fe}\dfrac{\dfrac{u_{i,j,k}^n+u_{i,j,k}^{*}}{2}+ \dfrac{u_{i+1,j,k}^n+u_{i+1,j,k}^{*}}{2}}{2}-u_{fw} \dfrac{\dfrac{u_{i,j,k}^n+u_{i,j,k}^{*}}{2} +\dfrac{u_{i-1,j,k}^n+u_{i-1,j,k}^{*}}{2}}{2}}{dx_i + dx_{i+1}}\quad , \end{align}   which give me this  Now, I am wondering how I can align it to the left side? I tried eqnarray, aligned and flalign, but they did not help.  Thanks in advance

Here is my code:   \begin{align*} (a-bu)e^{-\frac{1}{4}(v^2+u^2)(1+c)+\frac{1}{2}(1-c)u|v|}  &=(a-bx-by)e^{-\frac{1}{4}((x-y)^2+(x+y)^2)(1+c)+\frac{1}{2}(1-c)(x+y)(y-x)}\\ &=(a-bx-by)e^{-(x^2+cy^2)} \\ &=f(x,y). \end{align*}   I have a long equation. My question is as follows: I want to isolate the expression   (a-bu)e^{-\frac{1}{4}(v^2+u^2)(1+c)+\frac{1}{2}(1-c)u|v|}   on the first line so that I don't have an equation on the first line and I want this expression left justified with the other lines (that have the equal sign). How can I do this?


The title says it all, just wondered if accessing the iOS will count towards your consecutive visited days.

This isn't directly related to the app, but probably more on the APIs it's using. The last seen on the profile page doesn't seem to reflect that I'm actively using the Android app, or taking actions. I was able to vote on items and the last seen property on the profile page said I was last seen 50 minutes ago, when I was using a computer.  I'm assuming it won't count as a visit for the Enthusiast and Fantic badges either. I don't want someone angrily posting on Meta swearing they used the app for a day, yet they lost the consecutive days and has to prove it by showing they voted for something (we're probably far from this situation since it's alpha...)


I have some PDFs that I want to print in a color instead of the grayscale/black&white color.  I see some questions/answers about removing color. But I want to change to some color. And I don't see any options to do so. The PDFs are created from an epson scanner device.  I want to do that on linux.

I have no more black ink in my Canon MP560 printer.  All other colors print fine.  I need to print out an online train ticket.  When I print it out, I can't see any of the page that is in black (most of it, all the text).  I already printed it as a PDF so I can print it out later if I get some black ink in time.  But can anyone think of a creative way to tell the printer / printer driver / PDF software (Foxit) that it should replace all black pixels with e.g. very dark blue pixels so that I can at least print it out so that the barcode on the page can be scanned?


My question is very simple, What the different between the standardized coefficients (this coefficient has been obtain in multiple regression, and take a scale (-1,1). And the semi PARTIAL coefficient could be obtain in the model regression,but with this number you can take a variable contribution in percent (%). But in both cases this coefficients explain the variable's contribution. Both also control for the effect of one or more another variables. Thus, you could compare model results.

I don't even know if this question makes sense, but what is the difference between multiple regression and partial correlation (apart from the obvious differences between correlation and regression, which is not what I am aiming at)?  I want to figure out the following: I have two independent variables ($x_1$, $x_2$) and one dependent variable ($y$). Now individually the independent variables are not correlated with the dependent variable. But for a given $x_1$ $y$ decreases when $x_2$ decreases. So do I analyze that by means of multiple regression or partial correlation?  edit to hopefully improve my question: I am trying to understand the difference between multiple regression and partial correlation. So, when $y$ decreases for a given $x_1$ when $x_2$ decreases, is that due to the combined effect of $x_1$ and $x_2$ on $y$ (multiple regression) or is it due to removing the effect of $x_1$ (partial correlation)?


How can I find a file at the same time view the size of the file?  ERROR: I tried this command, but I only got the size and details of other files.  find -name "*.conf" | ls -l

I can easily find files with given string in name:  me@comp:/usr/local/hydra/hydra-7.4.2$ find -D stat -name "*hack*" ./hack881663129.txt ./hack881663129_7.txt ./hack881663129_5.txt ./hack881663129_4.txt ./hack881663129_4_7.txt ./hack881663129_6.txt ./hack881663129_1_6.txt ./hack881663129_8.txt   How can I also print file details, like size, date of creation etc.?


So I already took Pre-Calc, and ended up with a B both semesters. I am an incoming senior in high school. My special-ed case manager won't let me take it because she doesn't want to see me panic (crazy, right?). But, for some reason, I really like math. Is there a way for me to self-teach myself Calculus I or Calc I and II before taking it at college? I already have Humongus book of Calculus Problems and PatrickJMT on YouTube (My favorite math youtube channel).

I recently graduated with a degree in bachelor of science with a focus interactive and multimedia design. I had to opportunity to take 1 C++ course and 1 HTML course. I was also only required to take one math class, introduction to calculus (and it was hardly calculus, it was more of a math class for designers)  Since graduating I have pursued a career in web development. I'm considering going back for a MS in computer science or MS in web technologies.   I feel my math has suffered dramatically as I have always been behind most others on my math studies (middle school through college). I want to learn calculus as I feel it's an integral part of any CS degree.   Does anyone have any recommendations on any great books that I can read through and teach my self a bit of calculus or other advanced math topics?  Thanks for any advice


I've been dealing with this problem quite some time. I have this code \usepackage[top=2cm,bottom=4cm,inner=2.5cm,outer=4cm]{geometry} \usepackage{amsmath,amsfonts,amssymb,amsthm} % Links utilizables en el PDF final % \usepackage[colorlinks=true,allcolors=black,linktoc=all,hidelinks,linktocpage]{hyperref} % Cuadros en definiciones % \usepackage{mdframed}  \setlength{\parskip}{1em} \setlength{\abovedisplayskip}{0pt} \setlength{\belowdisplayskip}{0pt} \setlength{\abovedisplayshortskip}{0pt} \setlength{\belowdisplayshortskip}{0pt}  And this bit here Formalmente, el producto cartesiano de $A$ y $B$ es el conjunto $A\times B$ cuyos elementos son pares ordenados $(x,y)$ tales que $x\in A$ y $y\in B$:  \begin{equation*} A\times B = \{ (x,y) : x\in A, y\in B \} \end{equation*}  texttexttext  The problem is, it's producing a big whitespace around the equation and after like an hour fixing a similar problem with a theorem environment, I got this new one. They don't seem to be related as if I change the theorem, equation keeps having that space around. I also found in this site that abovedisplayskip, belowdisplayskip and so on would do the thing but actually nothing happens.  How to remove the space above and below the equation? Or if it's possible how to set a customizable option to change it?

users  I have some problems with linespacing in my thesis. One page look normal like this:    Another page look weird like this:    My preamble look like this:  \documentclass[a4paper,11pt,twoside]{report} \usepackage[utf8]{inputenc} \usepackage[english]{babel}  \usepackage{layout} \usepackage[protrusion=true,expansion=true]{microtype}   % Different usepackages \usepackage[T1]{fontenc} \usepackage[lf]{MinionPro} %% MinionPro \usepackage{icomma} \usepackage{setspace} \setstretch{1.1} \usepackage{siunitx,booktabs} \usepackage{graphicx} %% \usepackage{tocloft} - add if customize TOC \renewcommand{\cftsecleader}{\cftdotfill{\cftdotsep}} \usepackage{tabu}  % Chapter \usepackage[pagestyles ,newparttoc, explicit]{titlesec}% \usepackage{titletoc} \SetTracking[no ligatures = {f}]{encoding = }{100}  \usepackage[explicit]{titlesec} \titleformat{name=\chapter}[display]{ \figureversion{lining}}{\lsstyle\Large\MakeUppercase\chaptername\enspace \LARGE\thechapter}{2ex}{\LARGE\bfseries#1}%\uppercase  \titleformat{name=\chapter, numberless}{\lsstyle\LARGE}{}{0pt}{\MakeUppercase{#1}} \titlespacing{\chapter}{0pt}{2.5ex}{6ex}  % Table of Contents  \titlecontents{chapter}[0em]{\large\bfseries\protect\addvspace{15pt}}%\thecontentslabel\brlap[1.25\baselineskip] {\textssc{\mdseries\MakeLowercase\chaptername~{\footnotesize\thecontentslabel}}\\\medskip} {}% {\hfill\contentspage}%  % item / enumerate  \usepackage{enumitem}  % HTML code  \usepackage{listings} \usepackage{xcolor}  \definecolor{dkgreen}{rgb}{0,0.6,0} \definecolor{gray}{rgb}{0.5,0.5,0.5} \definecolor{mauve}{rgb}{0.58,0,0.82}  \lstset{frame=tb,   language=Java,   aboveskip=3mm,   belowskip=3mm,   showstringspaces=false,   columns=flexible,   basicstyle={\small\ttfamily},   numbers=none,   numberstyle=\tiny\color{gray},   keywordstyle=\color{blue},   commentstyle=\color{dkgreen},   stringstyle=\color{mauve},   breaklines=true,   breakatwhitespace=true,   tabsize=3 }   % Figure  \usepackage{chngcntr} \counterwithout{figure}{chapter}  % More pdf-pages at same site  \usepackage{pdfpages}  % References \usepackage[round, colon, sort, authoryear]{natbib} \setlength{\bibsep}{0.0pt} \setlength{\bibhang}{2em} \bibpunct{(}{)}{;}{a}{}{} \setcitestyle{notesep={: }} \def\citeapos#1{\citeauthor{#1}'s (\citeyear{#1})}  % Quotes \usepackage{csquotes} \MakeOuterQuote{"}  % Page margins \usepackage[left=3.5cm,right=3.5cm,top=3.5cm,bottom=3.5cm]{geometry}  % PDF background  \usepackage{eso-pic}  % Random text \usepackage{lipsum}  % Page style \usepackage{fancyhdr} \pagestyle{fancy}% <- ! % Defining MyStyle \fancypagestyle{MyStyle}{%     \fancyhead{}     \fancyfoot{}     \fancyfoot[RO]{\small{\leftmark} \ \ \hspace{2pt} {\vrule height 10pt width 1pt} \hspace{2pt} \ \small{\thepage}}     \fancyfoot[LE]{\small{\thepage} \ \ \hspace{2pt} {\vrule height 10pt width 1pt} \hspace{2pt} \ \lsstyle\small{\MakeUppercase{\chaptername}}\ \thechapter} \renewcommand{\headrulewidth}{0pt} % Remove header rule \renewcommand{\chaptermark}[1]{\markboth{\lsstyle\uppercase{##1}}{}} } % Redefining the PLAIN style \fancypagestyle{plain}{% \fancyhead{} %Clean headers \fancyfoot{} %Clean footers \fancyfoot[RO]{{\vrule height 10pt width 1pt} \hspace{2pt} \ \thepage} \fancyfoot[LE]{\thepage \ \hspace{2pt} {\vrule height 10pt width 1pt} \hspace{2pt}} \renewcommand{\headrulewidth}{0pt} % Remove header rule }   % Tabular \usepackage{threeparttable} \def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi} \includepdfset{pagecommand=\thispagestyle{plain}} \renewcommand{\TPTnoteSettings}{\footnotesize} \renewcommand{\TPTnoteLabel}[1]{#1}   Because of the text-length I only show you preamble. The rest is text and figures, where I use [ht].  Is there anyone who can help me.  Best regards


Let L be a language and let $\Sigma$ be a set of first-order L-sentences. Suppose that, for every natural number k, there exists an L-structure (M,I) such that (M,I) $\models$ $\Sigma$ and M has exactly k elements. Use the compactness theorem for first-order logic to prove that there is an L-structure (M,I) such that (M,I) $\models$ $\Sigma$ and M has infinitely many elements. Been a lil stuck on this question, I understand it somewhat but not sure how to incorporate the M being finite. One part that has struck out is that deductions must be finite.

I'm trying to prove the following: If $T$ is a first-order theory with the property that for every natural number $n$ there is a natural number $m>n$ such that $T$ has an $m$-element model then $T$ has an infinite model.  My thoughts: If $M$ is an $n$-element model then $\varphi_n = \exists v_1, \dots, v_n ((v_1 \neq v_2) \land \dots \land (v_{n-1} \neq v_n))$ is true in $M$. Can I use this to show that $T$ has an infinite model? How? Perhaps combine it with the compactness theorem somehow? Thanks for your help.


This is my first trip outside the country, never been on a plane before.. and at the same time I’m going alone. So I’m scared and worried and trying to do as much research as possible. Many sources say that I should be able to go with my identity card, but our ministry’s site still recommends a passport and that stresses me. A passport isn’t free and I don’t want to throw money around.  So is there any 0,0001% chance that I could be stopped because I don’t have a passport?  Yes, I’ve read the Dutch Identity Card post before I came here, but it’s not the same thing, at least that’s how I see it. And I want to make sure it works for my country too.

I'm traveling to Svalbard from the UK via Norway in a couple of weeks and would like to travel on my Dutch identity card. Is this possible?


Let $f$ be an entire function and suppose there is a constant $k>0$, and $R > 0$, and $n \in \mathbb N$ such that $|f(z)| > k|z|^n$ for $|z| > R$. Show that f is a polynomial and determine its degree.   I am almost sure my proof isn't correct. Hence why I really need help with this  My (Poor) Attempt  $f$ is entire and hence has a derivative at $0$ meaning the function;  and $$F(z) = f'(0)$$ when $z=0$  $$F(z)= \frac{f(z)-f(0)}{z}$$ otherwise.  It is well defined and continuous everywhere.   Since $f$ is entire, it has a power series expansion about $0$ that converges everywhere, which gives an expansion for $F(z)$ that also converges everywhere; therefore, $F$ is entire.   Now we see that if $|f(z)|> k|z|^{n-1}$ for $|z| > R$, then we can take $|z| > R$, which forces  $|F(z)| > \frac{|f(z)|+|f(0)|} {|z|} > k|z|^n + \frac{|f(0)|}{ R}$  Thus, if we instead take $|z| > max(R,1, |f(0)| R )$,  we will have $|F(z)|>(k + 1)|z|^n$. As a result , $ F $ is a polynomial of degree $> n$,   so away from $0$, $f$ is a polynomial of degree at most $n - 1$.  Of course, by continuity, this means $f$’s value at $0$ comes from the polynomial as well, and we are done.

I have a question in my assignment :     If $f$ is a nonconstant entire function such that $|f(z)|\geq M|z|^n$   for $|z|\geq R$ for some $n\in\mathbb N$ and some $M$ and $R$ in   $(0,\infty)$ show that $f$ is a polynomial of degree atleast $n$.   Now , I defined a function    $\ g(z) = \frac {1}{f(z)}\ $ such that $\ |g(z)| \le \frac{1}{M{|z|}^n}.$  Now , by using the cauchy inequality  $$|g^{(n)}(z)| \le  \frac{n!}{R^n |z|^nM}.$$    Considering that $ g(z) $ is an analytic function , it has a radius of convergence $ \infty $  $ \implies\  g^{(n)}(z) = 0.$    But if we go by this approach , then $ g^{(n)}(z) = 0 \ $ for any n . Also how can we be so sure that $ f(z) \neq 0 $ for any z ?  Is my reasoning correct or is there some other way to solve it ?


help, it keeps saying "failed to fetch" fetching the upgrade failed. There may be a network problem" but i am connected to the internet with lan.

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


Suppose that $A$ is an $n \times n$ matrix with $\| A\| \le a <1$. Prove that the matrix $(I-A)$ is invertible with $$ \| (I-A)^{-1} \| \le \frac{1}{1-a}.$$ (The choice of norm does not matter)  Please help me to solve this question, I totally have no idea about

$A$ is an $n\times n$ matrix with $\|A\|≤a<1 $ . I need to prove that the matrix $(I-A)$ is invertible with $\|(I-A)^{-1}\|\le\frac1{(1-a)}$.   It doesn't say anything more. The norm makes me confuse. How can we start to solve this. Could you please help?


i'm having some trouble trying to prove the next multivariable limit:  $$ \lim\limits_{(x,y) \to (0,0)} \frac{xy}{|x|+|y|} $$  I've already tried the different paths and the limit is 0, however i'm stuck trying to demonstrate it because those absolute values on the denominator, by using the theorem that our teacher taught us to do so.  The theorem 1.) 2.) goes as:   $$ 1.) |f(x,y) - L| < g(x,y)$$  Where L is the limit we calculated from the differents paths we got, 0 in this case, then we are supposed to calculate the $g(x,y)$ function by:  $$ |f(x,y) - 0 | = |\frac{xy}{|x|+|y|} - 0 | $$  This is the part where i'm stuck cause we are supposed to calculate that $g(x,y)$ through that formula, however i'm getting stuck because i don't know how to operate with this absolute value on the denominator $||x|+|y||$ any help on this one would be highly appreciated!   $$ 2.) \lim\limits_{(x.y) \to (x_o,y_o)} g(x,y) = 0$$  This one is just to evaluate the $g(x,y)$ we got from the formula above and it should be 0.

I have this function:  $$ f(x,y) = \frac {xy}{|x|+|y|} $$  And I want to evaluate it's limit when $$ (x,y) \to (0,0)$$ My guess is that it tends to zero. So, by definition, if:  $$ \forall \varepsilon \gt 0, \exists \delta \gt 0 \diagup \\ 0\lt||(x,y)||\lt \delta , \left|\frac{xy}{|x|+|y|}\right| \lt \varepsilon $$ Then $$ \lim_{(x,y)\to(0,0)}\frac {xy}{|x|+|y|} = 0 $$ So:  $$ \left|\frac{xy}{|x|+|y|}\right| = \frac{|xy|}{|x|+|y|} = \frac{|x||y|}{|x|+|y|} \le 1 |y| \lt \delta $$  So for any $$\delta \lt \varepsilon$$ the inequality is true. Hence, the limit exists and is equal to zero.  . Am I wrong or is Wolfram|Alpha wrong?


I have a method in the Family class  I want to add the value of the method to the JTextField from the Driver Class.   Eclipse keeps showing errors offering to make the method a string. Any help on how to do this would be great.   method   public boolean AnswerCall(String r) {     boolean AnswerCall = true;       if(r == "Brother") {          AnswerCall = true;      }else {         AnswerCall = false;      }      return AnswerCall; }   How I am currently calling it from the driver class that is extending Family.  JTextField jt9 = new JTextField(AnswerCall());

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


I was trying to install wine on my desktop install of 18.04 bionic and the website was formatted in a way I couldn’t highlight the commands so I started typing them on my tiny keyboard, with no backlight, and as a goon, I typed a typo, with the website dl.winehq.prg vs. org.  Well I exited the terminal (all terminals in fact) and put the web page into reader view and was able to copy the commands flawlessly, but when I try to run it again, typed correctly, it tries to access that website at .prg again, what do I do?

I've added many PPAs using the add-apt-repository command. Is there a simple way to remove these PPAs? I've checked in /etc/apt/sources.list for the appropriate deb lines but they aren't there.   This is on a server system so a command line solution would be great!


So here is the sentence written both ways. Which one is correct and maybe a description why so I can understand why. Thanks! /R  Leatherbacks need your help. They’re endangered and only 5% of the population are left.  OR,  Leatherbacks need your help. They’re endangered and only 5% of the population is left.

Possible Duplicate:             There is a large number of labourers who want to migrate to Japan for work.   I type this sentence in a word processor, and it reports an error that "is" should be "are" (subject-verb agreement).  I doubt this is a valid error. Could anyone confirm this?


When Gus invited Walt to his house for dinner, there was a short glimpse of his - probably - living room where we can see a toy car and a toy table. Was Gus’ family ever mentioned in the show? I think there was an implication of Gus being homosexual and the revenge he took on the cartel had also a personal aspect (murder of his partner). I can see a contradiction in this. Maybe he wanted to give Walter an impression that he is also a family man? If so, it would show how sociopathic Gus was.

In Breaking Bad, as far as I understood, Gustavo Fring never really had a family of his own. It is logical from one perspective not to have anyone valuable to you when doing business of the sort. However, following Gustavo's ability to keep his enemies close and display himself as a low profile business owner with normal life, I start to think that he should have had a family. Have there been any hints about his personal life, any ideas, thoughts or assumptions?