I have tried this code but it doesn't work:  private void Load_Button_Click(object sender, EventArgs e) {     using (OpenFileDialog ofd = new OpenFileDialog() { Filter = "Excel Workbook|*.xls", ValidateNames = true })     {         if (ofd.ShowDialog() == DialogResult.OK)         {              System.IO.FileStream fs = File.Open(ofd.FileName, System.IO.FileMode.Open, FileAccess.Read);              ExcelDataReader.IExcelDataReader reader = ExcelDataReader.ExcelReaderFactory.CreateBinaryReader(fs);              reader.IsFirstRowAsColumnNames = true;              result = reader.AsDataSet();              cboSheet.Items.Clear();               foreach (DataTable dt in result.Tables)                  cboSheet.Items.Add(dt.TableName);               reader.Close();              }      } }   I can't seem to run this code because the IsFirstRowAsColumnNames and AsDataSet has red underlines.  I found the code here


Schrödinger's equation for hydrogen atom (azimuthal part)

Now, The azimuthal part of the Schrödinger's equation for a hydrogen atom (after separating variables) is: $$ \frac{d^2 \Phi}{d \phi^2} + m^2 \Phi = 0$$ Which has solution $A e^{im\phi} + B e^{-im\phi}$, but I often see people assuming $B=0$, why?


Is there a name for these kind of doubled words?  For example:   hanky-panky flim-flam hoity-toity boo-hoo zig-zag   Note that some rhyme and others do not.


Returning ::iterator from function does not compile

The following repo compiles fine:  #include <tuple> #include <vector>  class Foo { public:      typedef std::tuple<int, int> foo_type;      std::vector<foo_type>::iterator Find() {         return Listeners.begin();     }      std::vector<foo_type> Listeners; };  int main()  {     Foo foo;      auto i = foo.Find(); }   But when I template the tuple on P, Q as in the following repo, I get this error:     syntax error : missing ';' before identifier 'Find'   #include <tuple> #include <vector>  template<typename P, typename Q> class Foo { public:      typedef std::tuple<P, Q> foo_type;      std::vector<foo_type>::iterator Find() {         return Listeners.begin();     }      std::vector<foo_type> Listeners; };  int main() {     Foo<int, int> foo;      auto i = foo.Find(); }


Deducing Lebesgue Integration from Riemann Integrability of a function

I have a question which I thought while studying a theorem in Chaptee Lebesgue Integration from Tom Apostol and it may seem easy but can anyone please tell about it.  Question: Assume that a function is Riemann Integrable on $[a, b]$ where $a$ and $b$ are finite. Then is it necessarily Lebesgue Integrable on $[a, b]$ ?  Why or why not? Please explain rigorously. Different books have a bit different treatment of Lebesgue integration, so can anyone please explain it while sticking to terminology of Tom M Apostol. I shall be really thankful.


How to hide notification center button in Mountain Lion?

I am using Mountain Lion.  The only advantage (for me) over the gesture is that Option + clicking the button enables/disables showing alerts and banners (toggles the switch in the notifications center).  Is there a way to hide the button in the status bar that opens notification center?


Is my SSD disk aligned to 4k sectors and if not how do I fix it?

As per , I'm trying optimise performance of a USB 3.0 attached SSD drive. I've been told that aligning to 4k boundaries should improve performance(?).  So how can I check that and fix it?  (Windows 7 Premium)


I am practicing for my algebra qual and I would like to know if $\mathbb{Z}[2\sqrt{2}]$ is a PID. I had no intuition at first except the fact that $\mathbb{Z}[i\sqrt{2}]$ is a ED with norm $N(a+i\sqrt{2}b)=a^2+2b^2$.  I tried proving that $\mathbb{Z}[2\sqrt{2}]$ is a ED with norm $N(a+b2\sqrt{2})=a^2-8b^2$ using the standard proof for $\mathbb{Z}[i\sqrt{2}]$ and $\mathbb{Z}[i]$. This led nowhere.  This may not be a PID, but I'm not sure how to prove it. Any tips? Thanks in advance.


Unexpected value printed when trying to print sorted array

Here is my code. Can someone help me with this error?  public class ExcahngeSort {      public double[] ExSort(double[] gangnam,int size)     { double temp;          for(int outrloop=1;outrloop<size;outrloop++)         {              for (int innrloop=0;innrloop<size-outrloop;innrloop++)             {                  if(gangnam[innrloop]>gangnam[innrloop+1])                 {                      temp=gangnam[innrloop];                     gangnam[innrloop]=gangnam[innrloop+1];                     gangnam[innrloop+1]=temp;                 }             }         }            return gangnam;     } }   I get an unexpected value [D@360be0printed. I don't know what this means.  Here is my main method:  public class BsortSimulate {     public static void main (String args []){          //BSort bs = new BSort();         ExcahngeSort es = new ExcahngeSort();         double gangnam [] = {12,24};          System.out.println(es.ExSort(gangnam, 2));          } }


Shortcut key is not working on windows 10

I have windows 8.1 . On my system I have configured some shortcut keys like CTRL+ALT+A will launch the Equra application. On my windows 8.1 when I press CTRL+ALT+A it starts the Equra app.  I also have configured it to run as maximized.It works fine on my system. But when I connected with one client to deploy this application on his windows 10 system. This shortcut key issue arrised.I have configured the shortcut key how I did on my pc but it did not work on his pc . I dont have windows 10 but next time in future when I will connect with him through anydesk I want to fix it. Why this shortcut key problem arrised on windows 10 pc and how to fix it. English is not my native language excuse me please : )


Why in Newton's law of gravity, we do $M_1 \times M_2$ and not $M_1 + M_2$?

In Newton's law of gravity $$F=\frac{G M_1 \cdot M_2}{r^2}$$ we do the product $M_1 \times M_2$ and not the sum $M_1 + M_2$. Why's that so?


Why is the speed of light in vacuum a universal constant?

While getting familiar with relativity, the second postulate has me stuck. "The speed of light is constant for all observers". why can't light slow down for an observer travelling the same direction as the light?


$X_i, X_j$ independent when $i≠j$, but $X_1, X_2, X_3$ dependent?

I've seen the statement:     It's possible that random variables $X_i, X_j$ are independent for $i≠j$, but $X_1, X_2, X_3$ are dependent.   I haven't been able to find examples of this though.  Any examples?


I am pretty well versed with SQL Server, MySQL, Oracle etc but putting these Database products aside, is there a resource that will help me design relational databases well? Is there something like patterns or best practices for database design?  I have seen a few times that database is often not scalable; people have personal preferences with keeping columns like isChecked column which is boolean in nature but stored as Char(1) with values like 'Y' and 'N' instead of 0 and 1 which to me sounds better. Ways not to commit common mistakes while doing database design?  Links to books or articles will be highly appreciated.  Thanks in advance.


How do I pass a variable into an FTP connection?

I'm using lftp to connect to a FTP server and am trying to cd into a specific directory, with that directory location saved as a variable, REMOTE_DIRECTORY.  I'm pretty sure this isn't working because of the spaces in the name of the folders, but I've tried both single and double quotes, which haven't resolved the issues I'm getting. Not sure what else to try. This is what I've tried:  REMOTE_DIRECTORY="SRC Test Data" export workdir=/home/ubuntu/tmp  lftp -u $USER,$PASS $HOST <<EOF set ftp:ssl-protect-data true set ftp:ssl-force true set ssl:verify-certificate no pwd  cd $REMOTE_DIRECTORY pwd cd 'SRC Test Data' pwd ls -d > $workdir/src_list quit EOF   The output of that script is:  ftp://FTP_User-RW:chars@sslftp.domain Usage: cd remote-dir ftp://FTP_User-RW:chars@sslftp.domain ftp://FTP_User-RW:chars@sslftp.domain/SRC%20Test%20Data   So it clearly is working only when I explictly enter in the folder name in the cd command. How do I do it though with the variable?


I'm reading a book and encountering the phrase "insert name is king" a lot. I'm wondering, what's the difference between them? When and why should I use "He is king" instead of "He is a king"?   Examples:        Tommen is king now   Yet if neither one is king, still, how could it be Lord Renly?   And he is a king, and you’re just a spy   Everyone else is a king or prince these days      Same with other words:        They elected him president.   They called him a thief.


How to use local html page as desktop/background

On a windows 7 computer how might one set the desktop to be a webpage. I want to have a local html file that I can edit as needed. Then windows should show that file as the background for the desktop but I should be able to click on links and interact with the page. Certain links would launch certain programs.   So I want to go this route because there is no way that I know to corral a group of icons to a certain part of the screen. When I disconnect and reconnect monitors and such things move around. No icons are forced to stay in part of the group they are supposed to be a part of. At this point I just have folders on the desktop with the app links in those folders. This means I have to open multiple folders to get where I want.   Any ideas on the html angle or other ideas on how to accomplish this?  thanks,  bye.


Error in projection modifier with tikz calc?

The image below was obtained with \begin{tikzpicture} \draw (0,0) coordinate (a1) -- (4,3) coordinate (b1) ; \draw (1,3) coordinate (a2) -- (6,1) coordinate (b2) ; \coordinate (c) at (intersection of a1--b1 and a2--b2) ; \coordinate (T) at ($ (c)!0.7!20:(a1) $); \coordinate (p1) at ($(a1)!(T)!(b1)$) ; \draw[->,thick] (p1) -- (T) ; \coordinate (T) at ($(c)!-0.7!20:(a2)$); % problem below: (p2) seems offset with respect to the correct % orthogonal projection on (a2)--(b2) \coordinate (p2) at ($(a2)!(T)!(b2)$) ; \draw[->,thick] (p2) -- (T) ; \fill (c)  circle (1pt) node[below]{$C$} ; \fill (p1) circle (1pt) node[above]{$P_1$} ; \fill (p2) circle (1pt) node[below]{$P_2$} ; \end{tikzpicture}   What I need are vectors at P orthogonal to PC. While P1 is acceptable, the vector at P2 is disturbingly leaning leftwards. How can I increase the accuracy of this image? Edit Reading the comments I fear that the above picture is like the infamous blue/black or white/gold dress: is vector at P2 orthogonal to its base line? For me definitely not. My question is what should I do to avoid this problem. Should I abandon calc and revert to trusted hand calculations? Edit The problem becomes more clear if we add a "true" perpendicular for comparison (see the red line below): \documentclass{article} \usepackage{tikz} \usetikzlibrary{calc}  \begin{document}  \begin{tikzpicture} \draw (0,0) coordinate (a1) -- (4,3) coordinate (b1) ; \draw (1,3) coordinate (a2) -- (6,1) coordinate (b2) ; \coordinate (c) at (intersection of a1--b1 and a2--b2) ; \coordinate (T) at ($ (c)!0.7!20:(a1) $); \coordinate (p1) at ($(a1)!(T)!(b1)$) ; \draw[->,thick] (p1) -- (T) ; \coordinate (T) at ($(c)!-0.7!20:(a2)$); % problem below: (p2) seems offset with respect to the correct % orthogonal projection on (a2)--(b2) \coordinate (p2) at ($(a2)!(T)!(b2)$) ; \draw[->,thick] (p2) -- (T) ; \fill (c)  circle (1pt) node[below]{$C$} ; \fill (p1) circle (1pt) node[above]{$P_1$} ; \fill (p2) circle (1pt) node[below]{$P_2$} ; % Added for comparison \draw[red] (p2) -- ($(p2)!-1cm!90:(c)$); \end{tikzpicture}  \end{document}


The difference between the Runnable and Callable interfaces in Java

What is the difference between using the Runnable and Callable interfaces when designing a concurrent thread in Java, why would you choose one over the other?


20.04 - How to remove/resize white space arround Desktop Icons

After I upgraded my Ubuntu 18.04 to 20.04, I got a couple of unspected surprises and saw that the icons on the ubuntu's Desktop have a white box/space arround the icon that profoundly annoys me. (as you can see in the image below)  On top of that it seems that I can't select multiple folders and move them around freely. Is there any way to solve this problem??


I have a 10 pound log of ground beef - I want to thaw it and make meat-loafs, meatballs, and hamburger patties - once made refreeze for future use - is this appropriate?


My first ever application for visa got denied under section 214(b)

I am doing my 1st year Master's degree in Biotechnology. I got selected for the Khorana Program for Scholars conducted by Indo-U.S. Science and technology forum, to do a 3 months internship at a U.S. University.   I have enough reasons to come back to India as I have to complete my Master's degree after returning so that I can apply for higher studies. There was a personal fund mentioned in my DS-2019 that is to be provided by my U.S. mentor as scholarship. I explained this in the interview. I didn't get any questions or asked for any documents to show my tie to my home country, although I brought everything with me.   What should I do next time to avoid visa rejection? Should I have provided them all the documents even if they didn't ask for it?


I have a HP Pavilion laptop and I was running Windows 10 on it. I installed Ubuntu 14.04 on it in a separate partition for dual boot using a LiveUSB and everything went well the first time.  When I had to restart after installing Ubuntu, I could not get the GRUB menu options to boot into either Windows/Ubuntu. I got the try Ubuntu and install Ubuntu options again. So I went ahead with install Ubuntu and went ahead with the installation. After that, I got a message to reboot the PC after removing the installation media. So I did that and did the reboot.   After the reboot, I could only access Ubuntu from the GRUB menu. I can't see any option to load Windows from GRUB.   I searched a lot in the forums and tried some stuff like boot repair and adding lines to the /etc/grub.d/40_custom and sudo update-grub but nothing seems to work.    Here is my   I logged into Ubuntu and tried the boot repair but it failed and the message popped up that I should use the boot repair from a Live USB or CD. So I created a boot repair live USB and performed the recommended repair. This is what I got :   GPT detected. Please create a BIOD-Boot partition (>1MB, unformatted filesystem, bios_grub flag). This can be performed via tools such as GParted. Then try again. Alternatively, you can retry after activating the [Separate /boot/efi partition:] option.     is an image of my partitions from GParted.  Thanks for the help!


A possible incorrect application of Law of Large numbers

A friend left this teaser for me. He asked me to first compute:  $$ \lim_{n \to \infty} \frac{\binom{2n}{n}}{2^{2n}}$$  Using Stirling's approximation (and another method), I got the answer as $0$. Then he gave the following "proof" for me to check:  Let $X_i$ be iid Bernoulli$(1/2)$. Then we have  $$ P\{\text{n out of 2n $X_i$ are 1} \} = P\{ \sum_{i=1}^{2n}X_i = n\} = \frac{\binom{2n}{n}}{2^{2n}}$$ $$ = P\left\{\frac{\sum_{i=1}^{2n}X_i}{2n} =\frac{1}{2}\right \}$$ $$ = P\left\{\frac{\sum_{i=1}^{2n}(X_i - \frac{1}{2})}{2n} = 0\right \}$$  Denote $E_n := \frac{\sum_{i=1}^{2n}(X_i - \frac{1}{2})}{2n}$  He argues according to Weak law of large numbers, $\forall \epsilon > 0$ $$ \lim_{n \to \infty} P(|E_n| < \epsilon) = 1 \Rightarrow \lim_{n \to \infty} P(|E_n| =0) = 1 \Rightarrow \lim_{n \to \infty} P(E_n =0) = 1$$  Hence the limit must be $1 \neq 0$.   I, for some strange reason, was unable to refute his proof although I suspect that the bug is in the last step somewhere. I would appreciate any help/hints on this.


This was the question of a test. My question is if my attempt to solve it is correct, and if it is, why is it correct.  $$\lim_{(x,y) \to (0,0), x+y \neq 0}{\frac{\ln(1-x-y)}{x+y} } $$  My attempt:   Let $\xi = -x-y $. Then $\xi \to 0$ whenever $(x,y) \to (0,0)$ and $x+y \neq 0 \iff \xi \neq 0$. (Is it then correct to say that the previous limit exists and is equal to the following iff the following exists? And why?):  $$\lim_{\xi \to 0, \xi \neq 0}{\frac{\ln(1+\xi )}{-\xi}}$$   If it is correct, then the limit exists and is $-1$. If it is correct, why is it correct?


Famous Question badge awarded for a question with negative score

I just noticed that  got a Famous Question badge for .  However, the question has a negative score. How come the badge was awarded for what appears to be a "bad" question?


Siri's voice on macOS Sierra is not natural

One thing I've noticed while using Siri on macOS Sierra is that Siri's voice is not natural (not even close to natural, it sounds like the default system voice of my Mac). How can I get Siri on macOS to sound as high-quality and natural as Siri on iOS?  I have downloaded Samantha voice for Mac before. I even tried deleting Samantha's voice and redownloading it, but Siri's voice is still like a robot!  When I change Siri's voice to Male (or any other accent or language) and then revert it back to Female, the voice gets better (still not the Siri I have on my iPhone), but then again after a few moments, it's back to default system voice.  What is going wrong here?


I want to setup a shared folder on Windows 10 host and Linux Mint guest to transfer files on VirtualBox. But when I Go to Devices/ Guest Additions, this error pops up. Anyone has any idea what is happening?


I have some issues with my SEO. The goal of the web site I am creating is to display all of my products by category and then by sub-category. My question is: if I display my products in archive category pages and in archive subcategory pages, will google see it duplicate content? Please excuse me for my English. Thanks in advance !


If in a semigroup $S$, $\forall x \exists ! y:xyx=x$, then $S$ is a group

If for all $x$ in a semigroup $S$, there exists a unique $y$ such that $x y x=x$, then $S$ is a group. (Not to be confused with , where only $y$ satisfying both $xyx=x$ and $yxy=y$ is unique)  After tring with no result, I used Prover9 to find a proof. I did get one but it was very hard to understand (possible to go through once but really hard to remember what the point is).  Is there any somewhat comprehensible or conceptual proof to this? Is there a theory underlying this?


Pasting text without interpreting as formula

I'm trying to copy a table of data from a website into Google Sheets. The table includes a column whose numbers are preceded by +/-, e.g., +/- 33. Excel works just fine, allowing me to paste in the table, and it correctly interprets the column as text.  However when I paste into Google Sheets, it interprets this as a broken formula, showing #ERROR for each column, and issuing a Formula parse error. Is there any way I can paste a table and prevent sheets from converting the text to formulas?   Sample source data to copy and paste to duplicate the problem:  +/- 1 +/- 456


What causes a "Java Hotspot 64-Bit Server VM Warning"?

I get this warning:     Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release   What does it mean?


I have a content type of Company, which can have multiple Images. In the company node, i want to display a slideshow of the images which belong to the company.   For some reasons, instead of storing the images in a field of Company, i created another content type of Image, which references the Company through an Entity Reference field type.   So now i have a view of Images which i want to filter using the reference field. I tried adding an Contextual Filter, but the filter cannot find the related images, which i think because the url is transformed. For example if the company has the name The Company, the path becomes /company/the-company (i am using automatic alias).  How can i filter the images correctly in the company page? Thanks.


If  $G_1,G_2$ are groups, $\varphi:G_1 \rightarrow G_2$ is a homomorphism and $a \in Z(G_1)$, is it true that $\varphi(a) \in Z(\operatorname{im}\varphi)$?  My attempt so far: I define $\varphi:G_1 \rightarrow G_2, \varphi(a)= \frac1a, a\in\mathbb Z$. which is not an integer. Also, $\varphi$ is a homomorphism since $a,b\in \mathbb Z :\varphi(ab)=\frac1a\frac{1}{b}$. Is this a valid counterexample?


My compitations: Base Case= $8-3 = 5$ is divisible by $5$  Inductive Hypothesis$=$ $8^k - 3^k = 5M$  $8^k = 5M + 3^k$ $3^k = 8^k - 5M$  My final answer is $5(11M + 11^k)$ Please tell me if I have any mistake regarding my computations.


I would like to have a tilde like this: ~some text  But it seems hard / impossible to easily achieve that in LaTeX.  Is it possible to have a "vertically centred" tilde which also looks like a "normal" tilde and is represented by that character so it is possible to search for it in the text? Additionally I wanted to know why this seems so hard to achieve in LaTeX as that would help me understand the philosophy and mindset of LaTeX and to use it better and more efficiently. My current effort looks like this but the tilde given by \textsuperscript{\texttildelow} is vertically too high. the nation's \texttildelow $\sim$ \textasciitilde \textsuperscript{\texttildelow} 2,500 high complexity


What is the best practice to generate positive and negative voltages to power an OpAmp

I would like to supply +4.5V & -4.5V to OpAmp using a 9V battery. I have tried using  which works.  Please suggest if this is the best practice, are there any better ways of doing this.  Note: Output current required is below 100mA.


How to programmatically create a Certificate Signing Request (CSR)?

How to implement it in C?  openssl req -new -key cert.key -out cert.csr  openssl x509 -req -in cert.csr -CA rootCA.crt -CAkey rootCA.key -CAcreateserial -out cert.crt -days 5000


Why do we not store names in a separate table?

Practically, I would never store names for customers in a separate table.  But why not?  It's a one to many relationship (a person can have one name but that name can be used by multiple people).  Isn't it proper design to separate one to many relationships over multiple tables, or am I missing something?


Determine the value(s) of the ratio $x:y$ if $2x^2-xy-3y^2 = 0$

I was asked to determine the value(s) of the ratio $x:y$ if $2x^2-xy-3y^2 = 0$. I didn't know what this meant, so I just solved the equation to get $x = -y$ or $x = \frac{3}{2}y$. What does the question mean?


Can A Static Resource Be Accessed From Site?

Pretty simple question. I have a VisualForce Page on which I have the following line:  <apex:stylesheet value="{!URLFOR($Resource.MyStyleSheet)}" />   When I access this page via a SiteIt's not loading, and when I look in the console I see this error:     Failed to load resource: the server responded with a status of 404 (Not Found)   Do I just have to inline everything?


What phrase or expression is used to describe someone who speaks eloquently?

I have heard the phrase a few years ago and now I can't remember it. It's a figurative phrase or expression used when someone has the skill of speaking fluently with a great lexicon, someone eloquent. It's not silver tongue. It goes more along the lines of someone that has the gift/touch of someone. The first and only time I heard the phrase was from a video of someone one (can't remember who it was) during an interview and they were acknowledging their way of well speaking because they had the insert phrase here. EDIT: I kept searching in Google using my keywords and 20 minutes after posting this I found it! It was the gift of gab.


Find the sum of the series $\sum_{n=1}^{\infty}\frac{1}{2^n-1}.$

Find the sum of the series: $$\sum_{n=1}^{\infty}\frac{1}{2^n-1}.$$  The series converges (using either the comparison test, or the ratio test). But can the sum be somehow calculated? Thanks in advance.


interrogation point (question mark) instead of citation call-out

I have a problem with the citation in winedt .When I put \cite and compile the code I find interrogation point in pdf generated . The winedt does not show any error but he show a 3 warnings    This is the code guy's  \documentclass[a4paper,11pt]{book} \usepackage{natbib} \usepackage[squaren, Gray, cdot]{SIunits} \usepackage[export]{adjustbox} \usepackage{subcaption} \usepackage{caption} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{mathpazo} \usepackage{graphicx}   \begin{document}      bla bla bla bla bla bla bla bla bla \cite{ben_mot_dies}       \bibliographystyle{plainnat}      \bibliography{mot}  \end{document}    Also this is the bib_text :  @MASTERSTHESIS{ben_mot_dies,   author =       {Benarfaoui.B},   title =        {Etude du moteur Diesel},   school =       {Université         de Mohamed Kheider Biskra},   type =         {Mémoire fin d'étude}, } @book{cleynen2015thermodynamique,   title={Thermodynamique de l'ing{\~A}{\copyright} nieur},   author={Cleynen, Olivier},   year={2015},   publisher={Lulu. com} }   Thank you


Howto compare two entities in JPA onPreUpdate

I am working with OpenJPA 2.2.1 and would like to do the following:  1) Load an entity 2) Change the entity 3) Check the changes done before saving the entity  What I've done:  1) Load the entity via      EntityManager.find(MyObject.class, id);   2) Ok, pretty clear, I think, something like      MyObject obj = EntityManager.find(MyObject.class, id);     obj.setName("New name");   3) Tried to evict the object from the PersistenceContext and loading it again from the database via:      EntityManager.evict(MyObject.class, id);     EntityManager.find(MyObject.class, id);   The entity returned by the find() call in 3) is always equal (equal ID) to the entity found in 1)  I thought I could remove the entity from the PersistenceContext / cache by evict.  How can I achieve to have two different entities: a) the changed entity and  b) the original entity from the database loaded in step 3)  And: If i refresh() the entity I expect the find method to return the refreshed one. Is that correct?  I tried the @PreUpdate listeners too with the same result so I think there must be something I have not understood regarding JPA PersistenceContext or Java references...  I hope I provided enough information! Thanks in advance!


Is mathematical practice:   an act of discovery of eternal objects and ideas independent of human existence; an intuition-free game in which symbols are manipulated according to a fixed sets of rules; or a product of constructions from primitive intuitive objects, most notably the integers?   I would like someone to explain what schools of thought are behind these definitions, what is relation between them, can all be equally valid, is there the most accurate definition among them, and all related questions...  I am just a laymen interested in philosophy.


For a positive integer $n$, prove that $\sum_{d|n}{\mu^2(d)/\phi(d)=n/\phi(n)}$

For a positive integer $n$, prove that $$\sum_{d|n}{\mu^2(d)/\phi(d)=n/\phi(n)}$$ I suspect something is missing here. I guess there is on extra condition on $n$, which is $n$ must ne square free. Because when I substitute $n=20$, the equality does not hold. Can anyone clarify for me ?


On the order of elements of $\mathrm{GL}(2,q)$.

There's a particular property of the elements of $\mathrm{GL}(2,q)$, the general linear group of $n\times n$ matrices over a finite field of order $q$, that I don't understand.  I know that the order of $\mathrm{GL}(2,q)$ is $(q^2-1)(q^2-q)=q(q+1)(q-1)^2$, since there are $q^2-1$ possible vectors for the first column, excluding the $0$ vector, and $q^2-q$ possible vector for the second column, excluding all multiples of the first.  So the order of any element must divide $q(q+1)(q-1)^2$ by Langrange. However, there is a further detail that      any element of $\mathrm{GL}(2,q)$ must have order dividing $q(q-1)$ or $(q-1)(q+1)$.    Is there a reason why one can narrow down the order to divide one of those smaller factors of $q(q+1)(q-1)^2$? Thanks!


How can you back up programs installed for reinstallment

I am wondering if there is a way that I could make a back up of programs or the packages used for installation.   I usually have a handful of programs installed and sometimes I end up having to reinstall my programs whenever I mess something up with the Ubuntu install.  These are either by  'apt-get' or by the GNOME store.  So I cannot install by a '.deb' package for all programs I have.  So I am wondering if there is a way to excract a program or the packages so that if I need to reinstall them, I can easily do so.


Allow the original poster the option to apply a rejected suggested edit on their own post

This isn't to change to the current rejection process or review queue in any way.      There was recently a  on one of my answers.  It was correct to reject from the reviewer's point of view, because variable names in code were changed, however, the edit would have been beneficial to the post in this case, and I would have liked the suggested edit to have been accepted.  I edited my answer and manually added the rejected suggested changes myself. On this occasion it was a small edit, but this would be quite time consuming if it was a more substantial edit.    It would be useful if we had a feature where a user can approve/improve an edit on their own question or answer which was previously rejected by community review.  Ideally, there would also be the option to Edit & Approve so we can change any bits if necessary.    Perhaps (for example) an option in the Suggested Edits history where only the OP, and maybe moderators, can select to approve or improve a rejected edit.   OPs can currently approve suggested edits, overruling the review queue, so this would just be an extension of that - being able to approve after 3 users have rejected.


My OpenID provider is shutting down; how do I change my Stack Exchange login?

Sometimes OpenID providers end their services, like  and  did. How do I add or remove login methods so I don't get locked out of my Stack Exchange account?     For more information, see  in the Help Center.


I have a set of all bounded sequences of real numbers with the metric $d$ defined as:  d(a, b) = sup$_n|a_n - b_n|$.   I want to prove this is a complete metric space, i.e. every Cauchy sequence is convergent.   My attempt at Solution:   Consider a Cauchy sequence $a_n$.  For every $\epsilon > 0$, there exists an $N \in \mathbb{N}$ such that for all $m, n > N$, we have sup$_{n, m} |a_n - a_m| < \epsilon$. $\implies $ $|a_n - a_m| < \epsilon$ for all $n, m > N$.   Every bounded sequence in reals has a convergent subsequence - call this subsequence $a_{n_k}$. Hence, for every $\epsilon > 0$, there exists an $M \in \mathbb{N}$ such that for all $k > M$, we have $|a_{n_k} - L| < \epsilon$ $\implies $ sup$_k |a_{n_k} - L| < \epsilon$.   Let $N^* = \max \{N, n_M \}$ so that for all $n, m > N^*$ and $n_k > N^*$ for some $k > M^*$, we have:   sup$_k|a_{n_k} - L| < \epsilon$ and  sup$_{n, m}|a_n - a_m | < \epsilon$.   Then,   $|a_n - L | = |a_n - a_{n_k} + a_{n_k} - L| \leq |a_n - a_{n_k}| + |a_{n_k} - L| $.   Now if $k > M^*$ such that $n_k > N^* \geq N$ and also $n > N^*$, we have   $|a_n - L| \leq 2 \epsilon$  Hence, sup$_n |a_n - L| \leq 2 \epsilon$.


Why Does $ Come Before the Number But % Comes After it?

Let's look at these two sentences:  Color blindness affects 8% of men. That sandwich costs $8.  So why, when using the percent symbol do we put it after the word, but with money we place it before the word?


"Absolutely continuous random variable" vs. "Continuous random variable"?

In the book Limit Theorems of Probability Theory by Valentin V. Petrov, I saw a distinction between the definitions of a distribution being "continuous" and "absolutely continuous", which is stated as follows:  "...The distribution of the random variable $X$ is said to be continuous if $P\left(X \in B\right)=0$ for any finite or countable set $B$ of points of the real line. It is said to be absolutely continuous if $P\left(X \in B\right)=0$ for all Borel sets $B$ of Lebesgue measure zero..."  The concept I am familiar with is:  "If a random variable has a continuous Cumulative Distribution Function, then it is absolutely continuous."  My questions are: are the two descriptions about "absolute continuity" in (1) and (2) talking about the same thing? If yes, how can I translate one explanation into the other one?


A new (maybe?) idea about cooperation between development engineers and test engineers - is this feasible/good?

Suppose we want to develop a small module (time needed: two weeks of one developer). Then what about this new (maybe?) pipeline:   The test engineer starts working:   Think about all cases (including many edge cases) that we need to test.  Write them down as code using an automated testing framework. At this stage, the testing code all fails, because the business code does not yet exist.  After the test engineer finishes, the developer starts:   Develop business code. During development, run the test code above. (Now the dev does not need to use things like Postman to manually test his code over and over again.) The testing code may contain bugs, and the developer should fix it. (Since the testing code is mostly straightforward, it should be not challenging to fix) When all test code passes, the code is almost done.  The test engineer checks that the modification of tests does not throw away things he wants to test. Done.   P.S. We are talking about E2E tests here, not unit tests. IMHO unit tests should be done by programmers (is it correct?).  P.S. We are small teams, so maybe not able to use the methodology in big companies.  Is this methodology acceptable/wonderful/terrible/awful? Thanks for any ideas and suggestions!


I need to move cursor one position to right in input field, if backspace was pressed. But I can't get it how to move it   Code:      const [input, setInput] = useState('');     const onKeyDown = e => {     const startPos = Number(e.target.selectionStart);     const endPos = Number(e.target.selectionEnd);     //if backspace was pressed     if (e.keyCode === 9) {       e.preventDefault();       e.stopPropagation();       //here should be some function       setInput(e.target.value.substring(2, startPos) + e.target.value.substring(endPos));     }   };   <input onKeyDown={onKeyDown} onInput={e => setInput(e.target.value)}/>


Pairs $(p,q)$ such that $id: l_p\to l_q$ is bounded

find all pairs $p,q\in [1,\infty)$ such that $id: l_p\to l_q$ is bounded.   This just means I must find all $(p,q)$ such that $\|x\|_q \le C\|x\|_p$ for some $C$ dependent on $p$, $q$. I don't know where to start, it seems like I'm missing something obvious


Show that a continuous function has a fixed point

Question: Let $a, b \in \mathbb{R}$ with $a < b$ and let $f: [a,b] \rightarrow [a,b]$ continuous. Show: $f$ has a fixed point, that is, there is an $x \in [a,b]$ with $f(x)=x$.  I suppose this has to do with the basic definition of continuity. The definition I am using is that $f$ is continuous at $a$ if $\displaystyle \lim_{x \to a} f(x)$ exists and if $\displaystyle \lim_{x \to a} f(x) = f(a)$. I must not be understanding it, since I am not sure how to begin showing this... Should I be trying to show that $x$ is both greater than or equal to and less than or equal to $\displaystyle \lim_{x \to a} f(x)$ ?


I'm getting these beep codes - (2 short, pause, 4 short, long pause) - repeating.  I couldn't find the meaning of these codes on the internet, the PC model is Omron NSA-CPU01-E.  Does anyone know what they could possibly mean?


How to protect a new wood floor from renovation traffic

I have had hardwood flooring installed in my home, with further renovation (kitchen) upcoming. The kitchen floor is tile which I'm not worried about, but to get to and from the kitchen means travelling over the hardwood (urethane finish). The installers used cardboard from the shipping boxes to protect the floor as they were working over it. To keep the cardboard from sliding around, it was taped down with painter's tape. It only took them a few days to complete the work, after which I had no trouble removing the tape. The kitchen work is another matter; there will be activity spread over a few weeks.   I'm thinking of using the same technique as the flooring installers - lay down cardboard and secure with painter's tape, but I've read that you can only rely on 7-14 day release. Is this true? Will I have problems removing the tape from the flooring if left in place for 3-4 weeks? Will it damage, discolor or cloud the finish if left that long?


How to get iTunes 11 to Group by Album Name

tl;dr Is there an easier way / hack to get iTunes to display albums by album name? Currently it splits albums up by artist, then sorts the album names A-Z. Going through and manually changing the Album Artist will take way to long...    I recently upgraded to iTunes 11 and for the most part I like it. However one issue I have come across (and it would seem many others are in the same boat) is that iTunes is grouping albums by artists. For the most part this is fine, but when it comes to soundtracks and compilations things get hairy...    As you can see soundtracks for games or movies (eg the Shutter Island or Sin City soundtrack) is a compilation of different songs by various artists and iTunes is displaying albums in A-Z order but grouping them by Artist...  I've found that you need to set the 'album artist' to something like Soundtrack or Various Artists to get the grouping to work correctly. However this would take hours to do manually!!   Is there an easy fix for this behavious? Either by automating the Album Artist or by hacking iTunes to display albums grouped by album name?  iTunes 11.0.3


Recommended Books on Arcpy/Python and GIS

Does anyone have recommendations on books/workbooks that I can read that goes beyond a beginner's level for Arcpy/Python with GIS?  I've written several scripts, some simple, some complex, but I want to learn how to be more efficient, and how to look at my code and improve upon it. I learn best interactive workbooks, so I'm looking for a learning medium like that.


The arithmetic progression $a_N=(p-1)N+1$ contains infinitely many primes $q$ by Dirichlet. I have searched this part in wiki, but I din't get any relevant proof. Can any one prove it how $a_N$ contains infinitely many primes and what is Dirichlet proof? please explain.


Running a method every hour in the background C#

I'm writing a web-api and I plan on storing "sessions" of data in there. I want to call a method every hour to make sure that inactive sessions are ended.  The Database contains 3 timestamp fields. Session_Start, Session_End and Last_Activity. Everytime data in the session is updated, the Last_activity field updates.   I wrote a method to end inactive sessions, but how do I call that method every hour in the background, without interfering with the functionality of the webapi (how do I run the code in the background and still allow people to use the webapi)?


I am trying to prove $(ma, mb) =m(a,b)$ where $m$ is a positive integer.  Should I start like this :  $$(ma, mb) =d\\ d \mid ma, \quad d \mid mb\\ d \mid max + may\\ d \mid m(ax+by)$$  Then what should I do?


How to download wine on window 10 pc and install on Ubuntu PC

Basically I have a WNA 3100 USB wireless adapter but there are no drivers for it on Ubuntu. I read online I need to download and install wine in order to use the part.   How can I download wine on my windows 10 pc? I was going to put the files on a flash drive and put the flash drive into the Ubuntu PC.


What is the meaning of the XubuntuY string in Ubuntu package names?

Each package name is in the form: package-XubuntuY*_amd64(i386)  So my questions are:   What does the X stand for? What does the Y stand for?   for example binutils_2.22-6ubuntu1.3_amd64  What is the meaning of the numbers 6 and 1.3


How to validate file using hook_file_validate?

I want to validate my file, I'm using      hook_file_validate   function test_file_validate($file) {   $errors = array();    if (empty($file->filename)) {     $errors[] = t("The file's name is empty. Please give a name to the file.");   }   if (retstrlen($file->filename) > 255) {     $errors[] = t("The file's name exceeds the 255 characters limit. Please rename the file and try again.");   }   return $errors; }   But, when I am going to print_r($file) I am not getting any values, please let know how to use this function


How to make light shine through a prism?

I'm trying to make a scene like this:  But no matter how I mess with the bounce settings in cycles; the light just isn't coming out of the other side of the prism:   What am i doing wrong?


Why does an unhinged body rotate about its centre of mass?

If a force is applied to a body which does not act through its centre of mass, it rotates about its centre of mass and not any other point. Why?


Best introductory text on elementary number theory that is concise

I went through this thread on  asking about a text on number theory, but my question is slightly different.   I was looking for a short and sweet book on elementary number theory. I don't need it to be a definitive treatise on number theory. I just need to have book which covers enough material to advance to algebraic number theory. I have looked at the books by Niven-Zuckerman-Montgomery and the Jones' and the one by Burton. All of them were very readable and I would like to read at least one of them at some point. For now, I would just like a book (say 100 pages long) which can get me acquainted with most of the material needed for algebraic number theory. Basically there is a course on algebraic number theory that I wish to take which begins in a month's time and I have not done enough elementary number theory.


Linkifying backticked code containing [] adds backslashes

When turning a string containing square brackets such as sys.argv[1] into a link by selecting it and pressing CTRL+L I get the following result:  [`sys.argv\[1\]`][1]   This is rendered as  which is obviously incorrect. Instead, the markdown should look like this:  [`sys.argv[1]`][1]   which in turn results in a proper link with the proper text:


Why is the following true?  Given a matrix $A \in \mathbb R^{n\times m}$ with rank $r \le \min(n,m)$, there are row and column sets $$ \{ i_1, \ldots, i_r \}, \quad \{ j_1, \ldots, j_r \}, $$ such that the $r\times r$ submatrix $$ (\hat A_{s,t})_{s,t=1}^r = A_{i_s,j_t} $$ is nonsingular.    Of course, with the column rank of $A$ being $r$, we can find $r$ linearly independent columns of $A$. But how can we know that they stay linearly independent after restricting them to the $r$ similarly chosen rows of $A$?


I've a PHP page in which i define a JS variable at the beginning of it  <script>   var accountType = 1; </script>   Someone told me to save this variable in a JS file and add auto change version to the file like  <script src="/template/assets/js/type.js?v=<?php echo time();?>"></script>   I feel that's not the proper way to solve this issue, Is there any proper method to stop browser from caching JS  tags ?  Thanks in advance


How to Iterate over ConcurrentHashMap with HashSet as value and remove a string from the HashSet while iterating over the map?

I am starting to learn java and going through the following issue While trying to update values(Hashset) of ConcurrentHashMap when iterating over it - ConcurrentModificationError is shown while debugging - although the code didn't crash This is the scenario: concurrentMap = Key -> A Value -> ["a","b","c","d"] Key -> B value -> ["a", "j", "k", "l", "m"]  when i try to remove "a" while iterating over A it fails to update the hashset properly and fails to loop I saw the hashset update as follows [a, b, c, d] [b,c]  How can I remove 'a' from key A while i am iterating over A and update the hashSet properly ? private ConcurrentMap<String, HashSet<String>> concurrentMap = new ConcurrentHashMap<>();  private void parseItems(Item testItem) throws Exception {          Map<String, HashSet<String>> itemMap = ConcurrentHashMap <>(Myclass.getIdMap(testItem));         concurrentMap = new ConcurrentHashMap<>(itemMap);         for (String type : concurrentMap.keySet()) {             for (String id : concurrentMap.get(type)) {                 if (type.equals("MyType")) {                     myList = function1(MyType, id);                 } else {                     myList = function2(defaultType, id, "ID");                 }                 removeParsedIdFromCurrentMap(type, id);                  for (Item item : myList) {                     ConcurrentMap<String, HashSet<String>> newItemConcurrentMap = new ConcurrentHashMap<>(Myclass.getIdMap(item));                     addToConcurentMap(newItemConcurrentMap);                 }             }         }     }  private void removeParsedIdFromCurrentMap(String type, String id) {         HashSet<String> currentIdSet = concurrentMap.get(type);         //This removes the value 'a'         if (currentIdSet != null) {             Iterator<String> iter = currentIdSet.iterator();             while (iter.hasNext()) {                 String toRemoveId = iter.next();                 if (toRemoveId.contains(id)) {                     iter.remove();                 }             }             //How can I update the values of key A while iterating A?              updateConcurrentMap();         }      }  private void addToConcurentMap(ConcurrentMap<IOMType, HashSet<String>> newItemConcurrentMap ) {         for (String type : newItemConcurrentMap .keySet()) {             for (String id : newItemConcurrentMap .get(type)) {                 if (!checkIdParsed(type, id)) {                     concurrentMap.putIfAbsent(type, new HashSet<>());                     concurrentMap.get(type).add(id);                 }             }         }     }


How to speed up reaction time in Settlers of Catan?

I'm looking for ideas on how to make Settlers of Catan quicker to play between friends. Whenever I play with friends they complain that you have to stop all the time to decide what are you going to do: trade, build, exchange at a port so the game doesn't flow as good as it should. This could be because my friends (and me) don't play board games very much. No one seems to be able to make key decisions quickly. Any ideas/suggestions on how to deal with this issue of slow decision-making? Note: This question, unlike the other, is not about how to "shorten" the game by reducing the required number of moves. This question is about how to shorten the reaction time for a given move.


How to set subsections to custom alpha listing

\renewcommand{\thesubsection}{\thesection.\alph{subsection}}  The above line set subsections to alpha listing, so if I had subsection A, then using \subsubsection{} would result in A.1, A.2, ... and so forth. However, how can I modify the command so that I can have subsubsections that are A.1.1, A.1.2, A.1.3, ...?


Possible Duplicate:          I have a folder named "ed6b7b66d9c1d645bfce0f8b33c3" under C: of Windows 7. I was wondering what its purpose is and if it is safe to delete? Thanks!  It takes up 120 MB. Its content is as follows:


How to use Cyrillic letter as a mathematical symbol?

I want to use \cyrgup in my document for some derivations. Is there any package that needs to be installed?


Can anyone tell how to install  on Ubuntu?


Most efficient way how to generate a serial which is unique per customerid in the same table?

I have a log file, which holds a customerid, and an event type. I want to add a new column called sequence, which should be a increasing number, and should be unique per customer. The table is append-only, record-by-record, no transactions, and I'd like the sequence number to be computed by a default function on the column. What is the least CPU intensive way to accomplish this? I tried googling but there are just too many hits on 'auto-increment', 'sequence', and 'serial' for the simple cases.


and I trying to clone an object with Object assing.   const defaults = {    a: [],    b: [],    c: [],    d: [],    e: [],    f: [],    g: [] };  this.rowSetSlug = Object.assign({},defaults); this.rowSetObject = Object.assign({},defaults); this.rowSetModified = Object.assign({},defaults);    But when I fill one object like    this.rowSetObject.push(object);    And do a console.log()  console.log(this.rowSetObject); console.log(this.rowSetModified); console.log(this.rowSetSlug);   All same have the rowSetObject items, and if i fill another they replicate.  Thanks


Add folder name to beginning of filename

I have a directory structure as below:  Folder   > SubFolder1     > FileName1.abc     > Filename2.abc     > .............    > SubFolder2     > FileName11.abc     > Filename12.abc     > ..............    > ..........   etc. I want to rename the files inside the subfolders as:  SubFolder1_Filename1.abc SubFolder1_Filename2.abc SubFolder2_Filename11.abc SubFolder2_Filename12.abc   i.e. add the folder name at the beginning of the file name with the delimiter "_". The directory structure should remain unchanged. Note: Beginning of file name is same. e.g. in above case File*.  I made below Script     for /r "PATH" %%G in (.) do (   pushd %%G   for %%* in (.) do  set MyDir=%%~n*    FOR %%v IN (File*.*) DO REN %%v  "%MyDir%_%%v"    popd   )      Problem with the above script is that it is taking only one Subfolder name and placing it to the beginning of file name irrespective of the folder.


A simple pendulum moving at a relativistic speed - how does the period change?

I've been pondering the precise mechanism of time dilation for the example of a simple pendulum in two different situations:   The observer and ground are at rest in one frame of reference;  the pendulum is moving at high speed with respect to that frame. The observer is at rest in one frame of reference; the pendulum and the ground together move at high speed with respect to that frame.   user8260 has pointed out that in situation 1, in the pendulum's frame $g$ is greater by $\gamma^2$ compared to $g$ in the observer's frame. Thus in the pendulum's frame the period is less than it is in the observer's frame by a factor of $1/\gamma$, just as one would expect from time dilation.  But what about situation 2? Here, compared to the pendulum frame, the observer sees the pendulum with the same length in a stronger gravitational field, yet observes a longer period. Does the inertial mass of the pendulum change differently than its gravitational mass? Also, does the analysis depend on whether the plane of swing is perpendicular or parallel the direction of motion?


Transfer Clash of Clans village to another iPhone

I will soon buy a new iPhone. If I log in with my Apple ID in my new phone could I still access my Clash of Clans village without starting from scratch?


I wrote this method to check if the given string is a palindrome or not and depending on the result I implemented an if-else statement to print out something. I know the string is a palindrome but the result I am getting is different from what I expected. Here is the java code:  public class Palindrom {     public static void main(String[] args){         String palindrome = "DOT SAW I WAS TOD";         String result = "";          for(int i = palindrome.length() - 1; i > 0; i--){             result = result + palindrome.charAt(i);         }         if (result == palindrome){             System.out.println("Yes it is a palindrome");         } else {             System.out.println("No it is not palindrome");         }     }  } //No it is not palindrome   What I suspected the problem is on result == palindrome. Is this getting false because I am comparing two different objects? What method should I use to solve such problems?


What do potential postdoc advisers seek in research statement letters?

I am putting together my application for a postdoctoral position in theoretical condensed matter physics. The position is not a fellowship and is a regular postdoc position. If you have gone through the process of applying for such positions a number of times, or, even better, if you have reviewed such research statement letters, what are the main points that are sought/you seek in such letters? Specifically, should I put more emphasize on my PhD research to demonstrate my "depth of knowledge" on projects I have worked on (past research), or dwell more on things that I want/am capable to do (future research)?


Sci-Fi Short Story: Officer Fakes Going Over To Aliens, Advises Atrocities, Fakes Death to Galvanize Humans to Fight

It was a story where the world's military was soft, privates would all become generals, etc. He 'went over' to the alien enemy side to advise them. Told aliens a mass hanging would break resistance, knowing it would really infuriate the humans and unite them to really fight.  When he was finally cornered he launched an empty lifeboat deep into space to get it away while he ensured his body was destroyed in the alien ship. Earth forces would then retain their hatred and determination to track him down for revenge and thus stay hard and ready against other future invasions.


skype 4.3 cannot connect to account on ubuntu 14.04 LTS

I have being using Skype for a long time on my Ubuntu 14.04 LTS. From this morning on, Skype simple cannot connect to my account anymore.  That is my Skype version:     Skype 4.3.0.37   © 2014 Skype and/or Microsoft   My Ubuntu system:  LSB Version:    core-2.0-amd64:core-2.0-noarch:core-3.0-amd64:core-3.0-noarch:core-3.1-amd64:core-3.1-noarch:core-3.2-amd64:core-3.2-noarch:core-4.0-amd64:core-4.0-noarch:core-4.1-amd64:core-4.1-noarch:cxx-3.0-amd64:cxx-3.0-noarch:cxx-3.1-amd64:cxx-3.1-noarch:cxx-3.2-amd64:cxx-3.2-noarch:cxx-4.0-amd64:cxx-4.0-noarch:cxx-4.1-amd64:cxx-4.1-noarch:desktop-3.1-amd64:desktop-3.1-noarch:desktop-3.2-amd64:desktop-3.2-noarch:desktop-4.0-amd64:desktop-4.0-noarch:desktop-4.1-amd64:desktop-4.1-noarch:graphics-2.0-amd64:graphics-2.0-noarch:graphics-3.0-amd64:graphics-3.0-noarch:graphics-3.1-amd64:graphics-3.1-noarch:graphics-3.2-amd64:graphics-3.2-noarch:graphics-4.0-amd64:graphics-4.0-noarch:graphics-4.1-amd64:graphics-4.1-noarch:languages-3.2-amd64:languages-3.2-noarch:languages-4.0-amd64:languages-4.0-noarch:languages-4.1-amd64:languages-4.1-noarch:multimedia-3.2-amd64:multimedia-3.2-noarch:multimedia-4.0-amd64:multimedia-4.0-noarch:multimedia-4.1-amd64:multimedia-4.1-noarch:printing-3.2-amd64:printing-3.2-noarch:printing-4.0-amd64:printing-4.0-noarch:printing-4.1-amd64:printing-4.1-noarch:qt4-3.1-amd64:qt4-3.1-noarch:security-4.0-amd64:security-4.0-noarch:security-4.1-amd64:security-4.1-noarch Distributor ID: Ubuntu Description:    Ubuntu 14.04.3 LTS Release:    14.04 Codename:   trusty   Any suggestion why or how to fix it?  Thanks in advance.


What is the radius of convergence of the power series $\sum_{n=1}^\infty \frac{\sin(n!)}{n!} x^n$?

What is the radius of convergence of the power series $$\sum_{n=1}^\infty \frac{\sin(n!)}{n!} x^n$$  I found a question like this and there are four options    $R\geq 1$ $R\geq 2*\pi$ $R\leq 4*\pi$ $R\leq \pi$    where $R$ denotes radius of convergence.    I've tried hard but cant get it how to show in equality.  Also there is question in my mind that among four options if the series is not converge at the end point can we discard that option.  I'm not sure abut this since we know if anywhere "$<$" holds we can say "$\leq$" holds, but the converse isn't not true.


The close vote dialog should give an option to close without leaving a comment (like the review deletion dialog)

When deleting from the review queue, it's perfectly possible to do so without leaving a form comment:       Add a comment for the author?      Leaving a comment is optional, but can help the author learn how to improve their post or avoid making the same mistake in the future.   I'd like the same option to be available (maybe as a checkbox) when voting to close as a duplicate or using a custom reason to save me the trouble of manually deleting it later.    These comments are already deletable at will, so if I'd rather they not be posted at all in some cases, I should have that option. In both cases (duplicates, custom reasons), IMO they're unnecessary:   the close review already shows duplicates in tabs for custom reasons, they should be shown at the top in review instead of hidden in an editable comment (since the custom reason itself can't be edited). (And the reason is already shown in the close vote dialog anyway, so it's not as if they vanish if the comment is deleted, or, as I am asking, not posted at all.)     TL;DR:  I'd like an option to be made available which would allow me to vote to close without leaving a comment. I'm not asking for this to be made the default, nor am I asking that the comments not be posted at all in all cases for everyone.


How Can I Delete An Object In a Video Or Picture With Blender?

I am  trying to delete an object in my video using blender.  I think masking might have something to do with it.  Or I could be wrong.  For example:  I might have a stool with someone sitting on it.  Then in blender I want to get rid of the stool so it looks as if the actor is floating.  Help is appreciated.  Thanks  Note I am talking about live action video being edited in blender


How do I, a novice GM, deal with a PC who is constantly difficult?

I have a good friend playing in my game, but he's done things like:   Killing NPCs which direct the story, effectively ruining the rest of the group's chances. Spending all of his money on inane items like "appletinis" or "croissants". Killing civilians and guards without regard for consequences. One shotting bosses. Stealing treasure from other characters and refusing to give it back. Refusing to use his powers to help the group unless they offer him all of their best gear.   That's just a small sampling, but I hope it gets the point across.  I know that if I try to talk to him one-on-one he'll get angry. It's sort of his M.O. Whenever one of them confronts him he gets defensive as well.   I want him to participate because he's kinda supported the whole idea from the beginning but I'm worried that he's ruining the fun for the rest of the group. I also don't know the rules as well as he does, since I'm still really new to GM-ing - and tabletop RPGs as a whole - and he's been interested in these types of games for a while.  What sort of things can I do to make him play more effectively with the team?


How to replace ']' with a new string when the text is stored in variable?

My MWE is here     #!/bin/bash num=$(gsettings get org.gnome.settings-daemon.plugins.media-keys custom-keybindings | grep -oE '[0-9]+'|sort -rn|head -n 1) num=$((num + 1)) echo $num #gsettings set org.gnome.settings-daemon.plugins.media-keys custom-keybindings "[<altered_list>]" #gsettings set org.gnome.settings-daemon.plugins.media-keys custom-keybindings "[$key , $key $num]" key="/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom" list=$(gsettings get org.gnome.settings-daemon.plugins.media-keys custom-keybindings) newnum=$(echo "${list}" | grep -oE '[0-9]+' |sort -rn|head -n 1) echo $newnum sed -e "/]/${key}${newnum}/" ${list} #gsettings set org.gnome.settings-daemon.plugins.media-keys custom-keybindings "[$key , $key $num]" echo $key   I want to sed -e "/]/${key}${newnum}/" ${list} that means from -   ['/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom0/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom2/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom1/']      I want to get     ['/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom0/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom2/', '/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom1/','/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom3/']   add a extra custom3 in the input.


why we say"over in the meadow"? meanning | grammar

what is the grammar of "over in"?I can not understand.I know over means being up to something,but what about "over in "?


Looks like it's not a game: Yes, it does: So... does it look like it's a game?

I posted this question as a non-English mother tongue. I've seen a conversation as below (comments on ):  A: 8:56 Looks like it's not a game! B: yeah, it does.  So, did B agree to A or not? I am a bit confused with two interpretations.  Yeah, it looks like it's not a game Yeah, it looks like it's a game  I learned to say 'yes' or 'does' for a positive response and 'no' or 'doesn't' for a negative response. So, if B said 'does' to 'looks', the answer is (1.), but if he said 'does' against 'it is not', then the answer is (2.) One thing is that, 'does' cannot come after be verb, so I think (1.) is more probable. However, since I am not the native, I want to hear the answer from the native or an English expert.


Installing Windows XP from USB pen drive

I want to install Windows XP on my desktop computer (only XP), but my CD drive is not working.  I've only found installation tutorials on how to install it on the pen drive rather than from the pen drive.  How can I install Windows XP from a USB flash drive?


Is there a way to approximate mean from summary information with open interval?

I have only the following summary information from which I have to approximate the integral $\int_xxf(x)dx$.   Interval Frequency  20-40      12  40-60      18   60+       14    As the last interval is an open interval, I think I cannot find the midpoint of that interval and use $\sum_xxf(x)$ to approximate the integral. So, what is the usual practice in this case?


I made a GUI in Python and i just wanted to know how can i import a C file into python so every time a button is clicked on my GUI, different methods in the C program will be executed. I tried the 'Python' method of importing:  sys.path.insert(0, '/home/pi/Desktop/FTPclass.py') import FTPclass   That worked for the python file i imported, but when I do the same for my c file, it complains saying my "testinc" module doesn't exist.  Thanks for everyone help in advance. ~Neamus


How to package a command line software to an Application

I have a command line executable (written in C) with some related resources, and I would like to package it as an application (inside the .app folder). I tried appify.sh which could package shell script, but didn't work here. For this command line executable, I would like to open termial to show the STDOUT. I also found  , but didn't find how to package the executable and resources inside the folder. Should I write an Info.plist file? I tried but failed to get the right syntax. update As I tested, you cannot run the executable alone, as MacOS will run that without any pop-up window(Termial), and ignore all STDOUT. We can use Platypus to run sh/bash with -exec executable to do the trick as .


Regression on a non-normal dependent variable?

Does it matter if a dependent variable has a normal distribution or not when it is used in a regression?


If I have an array and I delete certain elements, I end up with an array that has non-consecutive keys:    var arr = [15,16,20,21,-1]; delete arr[1]; delete arr[3]; console.log(arr); // [0: 15, 2: 20, 4: -1]     How can I "reset" the array's keys?  I should end up with an array like so:  [0: 15, 1: 20, 2: -1]


What do you call someone that believes he is the only living being?

What do you call someone that believes he is actually the only living being and that everyone and everything that exist (besides him self) is a state of his own mind? I am not referring to a


I have just bought an Acer Aspire laptop with Windows 10 installed. Wife wants Windows but I prefer Linux. Had dual boot with Win 7 before and it worked well. I know it did not go well with Vista.  Can I just install Ubuntu alongside Win 10 and let it provide the boot loader as it did before? It was really simple with Win 7.


Find the probability of Filium (child) that are dark (and) heterozygote

Two mice are crossed and both are dark and heterozygote. Find the probability of their filium(children) dark (and) heterozygote in F1.  Here's what our teacher explained:    I don't understand. I thought it would be 1/2.


I am writing a script that should change directory based on the input and then go back to the directory where the script was executed.  I am currently doing this:  old_dir = os.getcwd() os.chdir(<new_dir>) #do something os.chdir(old_dir) #do something   Is there a Python equivalent of cd - which would change the directory to the previous directory?  The following  expects an answer using any module while what I am looking for is something similar to cd -.


Playing a barbarian, and thought the Magic Initiate feat would be a good way to grab some range cantrips and a single-use utility spell. Originally thought of going with warlock, but DM suggested I go wizard or sorcerer and grab Mage Armor so I could be a naked man with an AC of 18 (w/ 2h) or 20 (w/shield) at level one.  UD says that as long as I'm not wearing armor, my AC is base (10) +con+dex. Mage armor ups the base to 13. Would I still retain the dex & con bonuses, from unarmored defense?


I have a code like this:  string str = ""; for(int i=0; i<100000; i++){     ...........     str += ...; } return str;   but, this code is very slow, and when execute, it takes 7 minutes.  Do you think a solution would be?


Linear independence of $\sin(x)$ and $\cos(x)$

In the vector space of $f:\mathbb R \to \mathbb R$, how do I prove that functions $\sin(x)$ and $\cos(x)$ are linearly independent. By def., two elements of a vector space are linearly independent if $0 = a\cos(x) + b\sin(x)$ implies that $a=b=0$, but how can I formalize that? Giving $x$ different values? Thanks in advance.


$Q(n)$: "$P(k)$ holds for all $k<n$". Then why is $Q(0)$ clearly true?

It is a principle and proof from Introduction to Set Theory, Hrbacek and Jech.   In the proof, line 1 and 2, I couldn't understand why $Q(0)$ is true.   $Q(0)$ means that "$P(k)$ holds for all $k<0$".   I understood there are no $k<0$.   And then I couldn't proceed.


In most of the software I have used like Coreldraw and Microsoft Word the user can save a series of keystrokes by making a Macro, called an Action in Adobe products. How can the user make a macro in Blender? The video at  seems to show this, but is unclear since it doesn't seem to me that the author showed how to save and how the use the macro. Is there any other video tutorial describing how I can make a macro?


Is it possible to disable spell check systemwide?

I've just done a clean install of Yosemite, and in practically all of my apps I'm noticing those red underlines whenever I've "misspelled" something (or, more accurately, used an unrecognized name, technical term, piece of code, etc.). I have been disabling it app by app, although even then it doesn't always work - for example, when doing Google searches in Chrome it still shows up, even though I've disabled "check spelling while typing."  I've also gone to System Preferences/Keyboard/Text and unchecked "Correct spelling automatically," but this still doesn't seem to do anything.  Has something gone wrong on my system? And is there any more reliable way to completely disable this unwanted "feature?"


CompizConfig doesn't work with ubuntu 18.04

I installed CompizConfig properly with my newly installed Ubuntu 18.04 but it doesn't work. How can I fix this bug?


Why does this C++ code actually compile and work?

Consider the following code. Why does this work?  #include <iostream> using namespace std;  int main() {     int i[10] = {1,2,3,4,5,6,7,8,9,10};     int array = 4;     cout << array[i] << endl;  }   This compiles without warnings and errors and outputs 5.


How does the American PhD system works for foreign students?

I'm a MSc Theoretical Physics student from Italy, and I'll most likely graduate around the end of next year: for the Italian academic system, this means that I'll be ready to try to get into a PhD program (after 3 years of BSc and 2 of MSc). I'm considering other countries' universities too, and since I spent a year of High School in the US I was looking for information about it. For what I understood, their post-secondary education system is college (4 years) for a BSc, then either Master or PhD (? years). Is this understanding correct? If so, do they have special rules for foreign students who already have a BSc and a MSc?


how to divide the pyqgis code into many python modules

I created python script with one function that connect to mysql db, retrieves non spatial data, creates features and saves them into new layer. Below is the pseuodo code:  ###mysql_select.py def create_features (mysql_connection)     layer = QgsVectorLayer(xxx)     provider = layer.dataProvider()     QgsMapLayerRegistry.instance().addMapLayer(layer)     fields = provider.fields()     features = []      mysql_connection.cursor.execute("select * from tables")      for res1,res2,re3 in mysql_connection.cursor.fetchall():     #store results to a layer attributes      provider.addFeatures(features)     _writer = QgsVectorFileWriter.writeAsVectorFormat(layer, path_to_shape_file)  ###my_main_script.py #import mysql_select myConnection = MySQLdb.connect(db_credentials) create_features(myConnection) myConnection.close()   It works fine. But I want to divide all stuff to modules located in different .py files to get more comfortable development. I modified the code above to mysql_select.py and my_main_script.py according to the marks ### above. But I get the error "NameError: global name 'QgsVectorLayer' is not defined".  What is the problem? How to send layer variable to the external module? What is the best method to divide the code into different modules in this case? I have to make four sql selects and create 4 new layers, so to put all that stuff in one script seems not versatile to develop.  I`ve tried to put from qgis.core import QgsVectorLayer in the mysql_select.py and in the my_main_script.py but unsuccessful.


php - Manipulating text file will bug when overloaded?

I have a javascript web app that is calling a php script each time it recieves an event from the websocket (between 1 to 8 times each second, no specific interval).  I want to save this information (json) into a text file to be able to be able to use it for later purposes.  <?php $file = '../backtests/' . $_POST['name'] . '.txt';  if (!file_exists($file)) {     $to_add = '[' . $_POST['_data'] . ']'; } else {  $to_add = ',' . $_POST['_data'] . ']';  }  $fh = fopen($file, 'a') or die("can't open file");  $stat = fstat($fh); ftruncate($fh, $stat['size']-1); fwrite($fh, $to_add); fclose($fh);   ?>   Ok so the problem is, at the beggining the it is working, but after the file is getting 40-50 kb of text, it's getting corrupted, and php will start writing at the wrong part of the file, and so corrupting it.  I am not sure what causes this but I guess it's because the file is growing and php takes more and more time to edit it?   What other solution could I use?  Thank you.


In this example:  The instrument can be used to apply pressure to the subject. The instrument can be used for applying pressure to the subject.  Are both correct? Are there any nuances between the two?


How to change Windows 10 Lock screen time format?

My Windows 10's time format is 24 hour clock, this includes the taskbar but the lock screen is still 12 hour clock format. How do I change the format of my time in lockscreen?


how to find the limit of sum here? Can it be transferred to an integral?

$$\lim_{n\rightarrow\infty}\sum\limits_{k=1}^n \frac{k}{k^2+n^2}$$  I was trying to write it as an integral but failed, how to do it here?


If $a$ and $b$ are co prime and $n$ is a prime, show that:  $\frac{a^n+b^n}{a+b}$ and $a+b$ have no common factor unless $a+b$ is a multiple of $n$  Also enlighten me why $n$ has to be prime so that $\frac{a^n+b^n}{a+b}$ and $a+b$ have no common factor unless $a$+$b$ is a multiple of $n$?


Regression shows positive linear relationship. Then why this negative equation

I am trying to get my regression right. I want to see, if subs increase how much increase in revenue is seen. The dependent variable is Revenue while the independent variable is subscribers.   Least squares method regression shows the following equation 24.4x - 189,883,443. I can't make sense of it. If subs increase means increase in revenue, then why this?  There is no 0 value and the lowest value for subscribers starts with 10 m while revenue starts with 180 m  How can i make sense of y = 24.4x - 189,883,443. Why is the intercept negative. Does it mean that one sub increase would mean a revenue increase of 24.4


Why in a photo light lines of street lamps? How to remove them?

Shutter speed - 32 sec.  Aperture - f/9 ISO - 100 Lens - EF-S18-55mm f/3.5-5.6 IS II Focal Length - 39 mm   I have took the photo through the window, with the lights off


Does angle of minimum deviation depend on angle of prism? I know that angle of deviation does but I  don't feel like  the particular behavior is relevant for the angle of deviation as well? Please help me clarify it


What is the semantics of handout overlay specification for frame environment?

In the example below (when changed to beamer mode) there is a frame with two slides.  On the first slide the text "Text 1" is shown in red color.  On the second slide it is shown in blue color (default).  \documentclass[10pt,t,handout]{beamer} \usepackage[english]{babel} \begin{document} \begin{frame}<handout:2>    {\color<1>{red}Text 1}    {\color<2>{green}Text 2} \end{frame} \end{document}   For the creation of handouts, however, I have added an overlay specification to the frame environment to only include slide 2 in the handouts.  I would assume that the generated slide in the handout would have "Text 1" in blue and "Text 2" in green.  Surprisingly for me the result in the handout is a slide where "Text 1" is red and "Text 2" is green.  This brought me to my question: What is the meaning of an overlay specification for handout mode that is added to a frame environment?  Please note: I already found a workaround, namely to provide individual overlay specifications for handout mode to the \color command for "Text 1":  {\color<1| handout:0>{red}Text 1}   That is, I am not asking to figure out how to make it work - I rather want to understand the background.  Update: Although I had searched SE before, only after submitting I was pointed towards this question: .  The background is, that the line  {\color<1>{red}Text 1}   actually means  {\color<1| handout:1->{red}Text 1}   Thus, if I change the line to  {\color<all:1>{red}Text 1}   then the handout is generated as I had expected.


Is there a way to add new tags to a bunch of questions

On Stack Overflow, when you search for "ceres-solver", you find (today) . Almost all related to . When I posted a new question on this library earlier today, I created the new tag "ceres-solver", fine.  Then, I started adding the tag to the few first questions of the search result. But I'm wondering if there could be a way to add a new tag to a bunch of questions at once, rather than having to edit them all one by one....doing so is a real pain, and it would really make sense to add the tag to all those posts...


If $\mathcal{P}(A)=\mathcal{P}(B)$, then $A=B$?

Prove, disprove, or give a counterexample:      If $\mathcal{P}(A)=\mathcal{P}(B)$, then $A=B$.   Assume $\mathcal{P}(A)=\mathcal{P}(B)$. Since we know $A \subseteq A$, we know $A \in \mathcal{P}(A)$.  Since $\mathcal{P}(A)=\mathcal{P}(B)$, we know that $A \in \mathcal{P}(B)$.  Therefore, $A \subseteq B$ and $A=B$.  Is this proof okay?  Edit: I should note this isn't probability, $\mathcal{P}$ is the power set.


Can i Execute/reuse javascript code from C# (windows service)

I have a javascript code (business logic) runs on client side, i want the same logic to execute from windows service (C# code), instead of re-writing those complex javascript code to C#, is there any way to execute it from C# class itself. Because i want to run this code inside windows service


I'm using a laptop with Ubuntu 14.04, using a external monitor I can adjust the color temp of the external monitor using its physical buttons in the monitor.  The question is, is there a way to adjust Brightness, Contrast. R,G,B slider with Ubuntu using a Graphical User interface, is there such a GUI for adjusting color temperature?


Can I in general upgrade to one of the latest MacOS but not the most latest one?

For example, on one Macbook, I have Mavericks. If I consider the Catalina too new and might not be too stable yet, can I choose and upgrade to either Mojave or High Sierra?  (App store won't show search result for Mojave or High Sierra. I had to use a link and open in Google Chrome to get to either  or .)  The real question is, can I upgrade from one MacOS to another freely? That's because, if there are 7 versions that are commonly used by people (Mavericks, Yosemite, El Capitan, Sierra, High Sierra, Mojave, Catalina), then upgrading from one version to any one is "7 choose 2" and therefore there are 21 possibilities, and is that supported?


What logfile contains time of startup and shutdown?

I would like to analyze my PC usage and therefore have a list of when I shut down my laptop or alternatively when I logged out from my account in the last month. Is there any logfile containing this information and if yes, where can I find it?  Using Ubuntu 13.10.


How do I make Ground Check stop rotating with the character when it rotate?

How do I make my character routice without Ground Check rotating with it, but still follow my character?  Code:  using UnityEngine; using System.Collections;  public class Player: MonoBehaviour {  public float maxspeed = 10f; bool facingRight = true;  Animator anim;  bool grounded = false; public Transform groundCheck; float groundRadius = 0.2f; public LayerMask whatIsGround; public Vector2 jumpDirection = new Vector2(1f, 1f); public float jumpFocre = 500f; bool doubleJump = false;   void Start () {     anim = GetComponent<Animator> (); }  void FixedUpdate () {     grounded = Physics2D.OverlapCircle(groundCheck.position, groundRadius, whatIsGround);     anim.SetBool ("Ground", grounded);      if (grounded)         doubleJump = false;      float move = Input.GetAxis ("Horizontal");     anim.SetFloat ("Speed", Mathf.Abs (move));      GetComponent<Rigidbody2D>().velocity = new Vector2(move * maxspeed, GetComponent<Rigidbody2D>().velocity.y); } void Update() {     if((!doubleJump) && Input.GetKeyDown ("up"))     {         anim.SetBool("Ground", false);         float move = Input.GetAxis ("Horizontal");         jumpDirection.x = move;         GetComponent<Rigidbody2D>().AddForce(jumpDirection.normalized * jumpFocre);          if(!doubleJump && !grounded)             doubleJump = true;     }   }  void Flip() {     facingRight = !facingRight;     Vector3 theScale = transform.localScale;     theScale.x *= -1;     transform.localScale = theScale;     } }


Managing Transaction Log Size using a Maintenance Plan

Are there any best practices for configuring a Maintenance Plan in SQL Server 2008?  Currently, I'm removing database backups and transaction logs greater than 40 hours old, then backing them up.  Problem I've seen is that the transaction log is still very large.  Should I be including a Shrink Database Plan task?


How to implement common layouts instead of misusing tabular environments?

Note: My hope is that this can become a general resource for "use a list instead" comments. If you have suggestions for improvement, please let me know.    I often see comments such as      This layout should be typeset using a list, not a tabular.   and (my favorite, paraphrasing because I cannot find the exact quotation right now)     If every tabularx with an lX preamble was a list instead, the world would be a better place.   This is all well and good, and I can see the benefits (chiefly: page breaking mid-"row" and without specialty table packages).  A description environment gets close, but it has a fixed left indent that does not depend on the longest item name.  The  at  shows a way to do this using the environ and enumitem packages.    What other methods do you use to achieve this layout? I'd like to avoid manually specifying the longest label (its width, essentially). This is something that tabularx does not require, and I don't want it to be required in the solution to this problem either, if I can avoid it.    Alternatively, what other layouts are recommended for this type of content? Examples of common document elements for which tabularx is used include nomenclature lists and other lists of notation.    MWE  \documentclass{article} \usepackage{tabularx} \usepackage{lipsum} % just for blind texts \newenvironment{mylist} % what else goes here?   {\trivlist}   {\endtrivlist}  \begin{document}  \section{trivlist version} \begin{mylist}   \item[Text 2] \lipsum*[2] \end{mylist}  \section{tabularx version} \noindent \begin{tabularx}{\textwidth}{@{}lX@{}}   Text 2 & \lipsum*[2] \end{tabularx}  \section{description version} \begin{description}   \item[Text 2] \lipsum*[2] \end{description}  \end{document}


Calculate normals given vertices and indices

Can I calculate normals given vertices and indices? Can't figure out the code. Any help appreciated.   Edit: Could be it as simple as?:  function calculateVertexNormal(vertices:Array<Vector3>) {         var vertNormal:Array<Vector3> = [];          for(i in 0...vertices.length){             var v0 = vertices[i];             vertNormal.push(new Vector3(v0.x, v0.y, v0.z).normalized());         }         return vertNormal;     }   Edit 2: Trying like this, with no luck  function calculateVertexNormal(vertices:Array<Vector3>) {         var i = 0;          while(i<indices.length){             var A = vertices[indices[i]];             var B = vertices[indices[i+1]];             var C = vertices[indices[i+2]];              var v1 = new Vec3().subvecs(A,B);             var v2 = new Vec3().subvecs(A,C);             var norm = new Vec3().crossvecs(v1, v2);              normals.push(norm.x);             normals.push(norm.y);             normals.push(norm.z);              i+=3;         }     }


Someone who doesn't learn from the mistakes he made

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.


For example:  $ 2^3 = 2 \cdot 2 \cdot2 $   But what about a fractional power such as:  $$ 2^{2/3} =  ? $$    1) How would I explain this?   2) How would I find value?  3) How would computers calculate this number?


How to start For-Loop from beginn if the If-Condition is True

I would like to know how do I start a for-loop from 0 if the if condition is True  for i in range (3):    if a=1:       #leave if-condition and start from beginning in for-loop with i=0   Break doesn't help here, because with break I only can leave the if Condition, but I also want to start the for loop from beginning.


What is wrong with this "naive" shuffling algorithm?

This is a follow-up to a Stackoverflow .  There are established algorithms (such as the ) that one should use to shuffle an array, rather than relying on "naive" ad-hoc implementations.   I am now interested in proving (or disproving) that my naive algorithm is broken (as in: does not generate all possible permutations with equal probability).  Here is the algorithm:     Loop a couple of times (length of array should do), and in every iteration, get two random array indexes and swap the two elements there.   Obviously, this needs more random numbers than KFY (twice as much), but aside from that does it work properly? And what would be the appropriate number of iterations (is "length of array" enough)?


What are the limitations on the Shape Water cantrip?

I have been having a discussion regarding the Shape Water cantrip from the Elemental Evil Player's Companion. A friend and I are trying to come to an accurate view of how this spell actually functions.   Some example questions:   Must the targeted water be within a 5 foot cube area, or does it need to be of a volume not exceeding 125 cubic feet? If you shape water that is within a 5 foot cube, can the final shape you animate it to extend outside the cube? Can you cause the shaping to affect ice and snow, or only liquid water? Would you be able to carry a globe of water alongside you over distances?   Really, there are two parts:    What can be targeted by the spell? What are the limitations on the 'shape and animate' portion of the spell?   The answer I am looking for, if possible, would use the language of the spell, possibly with precedent from other game text, to clearly define the limitations of this cantrip.


Do I need an airport transit visa through Switzerland if I have a Schengen visa?

I am Egyptian citizen holding a single entry visa to Spain , travelling in 1 July but i will have 1 day transit in Swiss airport , so do i need a visa to enter Switzerland ?


least modulus for a zero of an analytic function

This question  is problem 562 taken from  from Lunts Aramovich and Volkovyskii: A Collection of Problems on Complex Analysis; the first hint is clear enough but I am stuck with the second hint: I want to prove that given $f(z) =\sum_{n \geq 0 } c_n z^n $ and $z_0$ verifying $f(z_0) = 0$, $|z_0| \geq \frac{\rho|c_0|}{M+|c_0|}$ if $M = \sup_{|z|=\rho} |f(z)|$ . First, the authors consider $D = \{ z / |f(z) - c_0| <|c_0| \}$ which is zero free for $f$; this is easy; then  $|f(z) - c_0|$ is to be evaluated using Cauchy's inequalities; I take $\zeta$ outside $D$; it is then possible that $f(\zeta) = 0$ and $M + |c_0| \geq |f(\zeta) - c_0| \geq|c_0|$. What to do next is a mistery for me.


Purpose of hole in stove leading to oven

I'm staying in a hotel and have access to a "electric coil stove" for one of the first times.  I accidentally turned on the oven light and saw that the light was shining up through only one of the stoves:    There's only a port from the oven into the top right stove, and note that the stove is not on.  Here's a view from within the oven:    Is there a hole here as a vent for the oven for some reason, or is this for the stove? I typically use a glass "flat-top stove" that doesn't have an oven underneath it. I've never seen a direct hole from a stove to the oven before, and have to wonder what the purpose is.


How To Make An If Statement Case Insensitive In Python

It can become quite tedious to put multiple variations of spelling into and if statement and I was wondering if there is a way I could make the if statements case insensitive so I only need to put in one thing. I'm just picking up python again and couldn't find a good way online.


Is there a shortcut to clear the command line when typing in it instead of keeping backspace pressed for a few long seconds?  I ask because I regularly use the Tab key to automatically fill in file names when using bash commands in the Terminal. For example instead of typing cd this_is_a_long_file_name, I will type cd th<Tab>. But then I realize I have filled in the wrong command/filename and I have to hold down backspace to clear everything and repeat the process.


Excel: Is there a registry setting to suppress the warning messages when saving spreadsheets in CSV format?

I work with many CSV files, and am constantly annoyed by the Excel dialog that pops up when I try to save a file:  "[your spreadsheet] may contain features that are not compatible with CSV (Comma Delimited).  Do you want to keep the workbook in this format?"  My answer is always going to be YES.  Is there a registry setting to suppress this confirmation dialog?


Scattering, Perturbation and asymptotic states in LSZ reduction formula

I was following Schwarz's book on quantum field theory. There he defines the asymptotic momentum eigenstates $|i\rangle\equiv |k_1 k_2\rangle$ and $|f\rangle\equiv |k_3 k_4\rangle$ in the S-matrix element $\langle f|S|i\rangle$ as the eigenstates of the full Hamiltonian i.e., $H=H_0+H_{int}$. Therefore, the states $|i\rangle=|k_1 k_2\rangle$ is defined as $$|k_1 k_2\rangle=a_{k_1}^{\dagger}(-\infty) a_{k_2}^{\dagger}(-\infty)|\Omega\rangle$$ where $|\Omega\rangle$ is the vacuum of the full interacting theory. Then the LSZ reduction formula connects the S-matrix element $\langle f|S|i\rangle$ to the Green' functions of the interaction theory defined as $$G^{(n)}(x_1,x_2,...x_n)=\langle \Omega|T[\phi(x_1)\phi(x_2)...\phi(x_n)]|\Omega\rangle.$$ Here are a few doubts. Doubt 1 When the particles are far away, the interaction can be considered to be adiabatically switched off. Therefore, at $t=\pm\infty$ the states are really free particle states and should have been written as $$|k_1 k_2\rangle=a_{k_1}^{\dagger}(-\infty) a_{k_2}^{\dagger}(-\infty)|0\rangle$$ and $$|k_3 k_4\rangle=a_{k_3}^{\dagger}(+\infty) a_{k_4}^{\dagger}(+\infty)|0\rangle$$ where $|0\rangle$ is the vacuum of the free theory.  I do not understand why these the states $|i\rangle$ and $|f\rangle$ are derived from $|\Omega\rangle$ instead of $|0\rangle$. Doubt 2 The initial and final states were derived from the vacuum of the interacting theory $|\Omega\rangle$. According to my understanding, this suggests that the states $|i\rangle\equiv |k_1 k_2\rangle$ and $|f\rangle\equiv |k_3 k_4\rangle$  are eigenstates of the full Hamiltonian $H$. Since then there is no perturbation, there should not be any scattering or transition at all.  More references Even Peskin & Schroeder, Bjorken & Drell, Srednicki take the same approach as Schwartz; they too define the external momentum eigenstates to the eigenstate of the full Hamiltonian $H$. However, if the system was initially in a stationary state why should it undergo a transition in absence of any perturbation?


How do I install drivers for TP-Link AC1300?

When I ordered this TP-Link AC1300 Wireless Dual Band PCI-Express Adapter (Archer T6E), I looked into customers reviews and they said it worked fine with no drivers on Ubuntu. I didn't have a CD/DVD player on my desktop so I (on a laptop with a DVD drive) copied and pasted the DVD support disk content on to a USB drive and used that. But when I tried to run autorun.exe it puts up archive manager and says An error occurred while loading the archive Ubuntu verison- Ubuntu 16.04 LTS.  Output from: lspci -vnn  02:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 11) Subsystem: ASRock Incorporation Motherboard (one of many) [1849:8168] Kernel driver in use: r8169  Kernel modules: r8169   I am fairly new to Ubuntu (1 month) and have learned alot (sudo commands) and now know that windows is overpriced and that ubuntu is better in most fields.  Thanks for the help.


I got weird problem with shading in my Blender. Anyone know how to fix this? Rendering, texutre and material looks good. Earlier I tried reinstall but nothing special happened.


I've been looking over the PostGIS "API" of functions, and I notice that most of them take two elements to compare. For example, the ST_Distance function takes two geometry/geography elements to find the distance.   There is no function to do something like: "Given a geometry G, give me the closest geometry GClosest in Table T where G.id <> GClosest.id"  I realize I could write a PL/PgSQL function to iterate over the table and call ST_Distance on each element, but I'm hoping there's a better, more efficient, solution.


(Fundamental) Solution of the Helmholtz equation

The fundamental solution of the Helmholtz equation in $\mathbb{R}^3$ $$(\Delta+k^2)u=-\delta \tag{1}$$ is well known:  $$u(x)=\frac{e^{\pm ik|x|}}{4\pi |x|}$$ solves the Helmholtz equation in distributional sense. The usual ansatz to obtain fundamental solutions is to Fourier transform both sides. Then $(1)$ becomes $$(-|x|^2+k^2)\hat{u}(x)=-1 \implies \hat{u}(x)=\frac{1}{k^2-|x|^2}.$$ The problem now arises is that we want to inverse Fourier transform $\hat{u}$ to obtain the solution. But $\hat{u}$ has singularities on the sphere of radius $k$.  How do we proceed in a rigorous distributional way to obtain the above fundamental solution? What do people usually do and is there any book about such problems?


What am I doing wrong while finding the Laurent series of $\frac{1}{\sin(z)}$?

I'm trying to compute the Laurent series of $\frac{1}{\sin(z)}$ at $z_0=0$. From what I've seen on the internet this is given as   $f(z)=\frac{1}{z}+\frac{z}{3!}+\frac{7z^3}{360}+...$  My attempt:  $f(z)=\frac{1}{\sin(z)}$ can be rewritten as $f(z)=\frac{1}{z}\frac{z}{\sin(z)}$  We can express $\sin(z)$ as $\sin(z)=z-\frac{z^2}{3!}+\frac{z^4}{5!}+...$  $\therefore \frac{z}{\sin(z)}=(\frac{\sin(z)}{z})^{-1}=(1-\frac{z}{3!}+\frac{z^3}{5!}+...)^{-1}$  To get this to equal what I know it should, then we should have $(\frac{\sin(z)}{z})^{-1}=(1+\frac{z}{3!}+\frac{7z^3}{360}+...)$ but how can this be what do I do with my negative sign and how do I obtain the $\frac{7}{360}$ coefficient?


"Write Error: No space left on device" when df displays 60% of free space?

It's been happening for the last few weeks in a small unix server (it doesn't have all standard unix commands, just the basics included in the BusyBox package) that I was configuring to backup files.   If we check the free space of the server it shows:   Filesystem             |   Size  |    Used | Available | Use%| Mounted on  /dev/hdc2              | 678.4G  |  416.6G |   261.8G  | 61% | /tmp/mnt/D  /dev/sda1              |  96.1G  |   36.0G |    55.2G  | 40% | /tmp/mnt/USB/USB_C   Now I am trying to copy either a 700MB files to USB_C or a 90GB files to /tmp/mnt/D where I can see that there's plenty of space available, however, I keep on receiving the followin error:  cp: Write Error: No space left on device   Any idea what the problem could be and how it could be fixed?  As mentioned, this is a small unix server with the bare minimum of unix commands, so most of the commands mentioned in other posts do NOT work for this box. Hence that I might need the help of someone who knows what I could try in this specific system to give us some clue...


how can i give a figure an extended caption without it going in my table of figures?

I am writing my minor thesis which includes a number of tikz figures, which are all listed in a table of figures.  the table of figures gives the figure number, and then the title of the figure, as given by the caption.  the way i have put them into my document is in the following manner:  % ---------------- \begin{figure}[h!] \centering \includegraphics{./tikz/network.tikz} \caption{Feed-forward neural network - The red line indicates the path a signal travels from input node $x_2$ to output node $y_4$.} \label{fig:network} \end{figure} %-----------------   My problem is that the whole caption is being printed in the list of figures, and i would like it only to have "Feed-forward neural network" in the list of figures.  I would be greatly appreciative if someone could explain to me how i can separate the figure title from extended description.  thanks


Why is "head over heels" used as if it were exceptional rather than commonplace?

Most people spend part of each day standing, and if they have normal anatomy their heads are over their heels in this position.  Even sitting or lying down, the head is higher than the heels (if not over the heels).  Yet the phrase "head over heels" is used in ways implying it is an unusual situation.  How did such usage come to be, and why does it persist?  Why is the more obvious "heels over head" not used?


Please suggest algorithms to encrypt and decrypt text messages that can be easily performed by human in a considerably short time. It doesn't have to be really secure, but sufficient to fool unskillful third parties.


How to associate an image with a term taxononmy and publish it on frontpage?

I couldn't find the solution anywhere else, so I believe is a valid question for this website. I think my problem is divided in two parts. I created a custom taxonomy called "Type" and within it, I have terms (tags) like "cool", "sad", "amazing"..and so on.   1) I want to associate an icon for each one of my terms. 2) I want to display those icons (within link to the term archive) in my front page, like a feature image for each post.  No idea how to do that. Help please.


Copy over ssh and execute commands in one session

Possible Duplicate:          Here is my sync script:  ssh user@remote.host /etc/init.d/some_service stop scp user@remote.host:/var/some_service/events ./events scp ./new_data user@remote.host:/var/some_service/new_data ssh user@remote.host /etc/init.d/some_service start   As You can see, it stops service, perform some copies with scp and starts service back.  The problem: it "costs" 4 "similar" ssh connections in a row.  Is there any way to make all the work, using one physical ssh connection?


I am writing my project work in LaTeX, but I am facing certain difficulties to write the sign (it is similar to hash sign, but not clearly).   Please help me to write this:


What is the best email username to use for a myname.com domain?

Let's say I have the domain johnsmith.com and I want people to reach me via email, what is the best email username to use?  Some examples:   john@johnsmith.com - redundant john.smith@johnsmith.com - redundant and looks kinda stupid mail@johnsmith.com - makes sense, but looks very "technical" me@johnsmith.com root@johnsmith.com - for the geeks among us ;-)   Of course, technically I can simply say that I will be able to receive *@johnsmith.com, however, for a better user experience I still just want one email address for public presence (website, business cards, etc.).  Any suggestions?


Is there a known good way to have a "computer" opponent play a Match 3 game? It doesn't have to be fancy, or even considered fair. If the AI always takes the best move on the board that would be OK with me. Note that a valid move is one that doesn't make a match.  Edit: What I am currently doing is a brute force approach. I look at every tile on the board, and see what the best move that tile can do. I add it to a collection and give it a score (based on how many it will match 3 or 4). Once I have traversed the entire board I use the move with the  best score. In the event of a tie I pick one.  If a 5 match combo is found I short circuit out to that one. 5 is the highest combo you can get)  I may not be able to improve it, but it feels like this should have been solved already.