I wanted to install Ubuntu alongside Windows 10. My ASUS FX553VD-DM234T laptop has a 128GB SSD and a 1TB HDD.   First of all, I made a clean installation of Windows 10 (booted from an USB to do so; not that built-in "reset") and deleted all partitions as soon as I had the chance to (so I got left 2 drives with 100% unallocated space each). I installed windows 10 on the SSD.  Then I created a 800GB partition on the HDD with Windows' built-in tool. 200GB unallocated space left.  Now I followed  guide (seemed to be the one I needed) step by step and I'm certain I didn't forget anything or got anything wrong.  And here's where I'm stuck now: as soon as the installation is done and I can click the "restart now" button, the computer freezes. What I did then (after several minutes waiting) was to force the computer to shutdown (pressing the power button) and try starting it up again and pick Ubuntu where I can chose between this and Windows. It's the same problem, it freezes during the loading screen (if it even gets until there, that is).  I couldn't find any solution, and I'm starting to get pretty frustrated after the third try now.  I don't know if this image helps.     I just thought it seems strange that both show the same drive (the SSD), even though I definitely installed Ubuntu on the HDD only.

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


Let $G$ be a group. Let $H$ and $K$ be two subgroups of $G$ and $K$ is normal in $G$. Show that $K$ is normal in $HK$. My attempt: We will prove that: \begin{equation*}     \forall z \in HK, \forall k \in K, zkz^{-1} \in K     \enspace . \end{equation*} Let $k \in K$. Let $z=h'k' \in HK$. \begin{equation*}     zkz^{-1} = h'k'k(h'k')^{-1}=h'k'k(k')^{-1}(h')^{-1}     \enspace . \end{equation*} Yet, $\forall k, k' \in K, \enspace k'k(k')^{-1} \in K$. Furthermore, by assumption, $K$ is normal in $G$ and $H$ is a subgroup of $G$. Therefore, $K$ is normal in $H$. So, \begin{equation*}     h'(k'k(k')^{-1})(h')^{-1}  \in K     \enspace . \end{equation*} which implies that: \begin{equation*}     zkz^{-1} \in K     \enspace . \end{equation*} In conclusion, $K$ is normal in $HK$. I'm really not sure about the fact that $K$ is normal in $H$. Could you confirm it?

Note K is a normal subgroup of HK  I thought I could just prove K is a subset of HK and vice versa so as to prove it a normal subgroup but then how to do this I have no idea because I keep getting hk element again while trying to do so.  I just tried to implement the steps to find HK is a subgroup of G.


I'm on Ubuntu 18.04, 64 bit.  I downloaded the .deb from the Steam website. I tried installing with Ubuntu Software. It didn't seem to work. I tried installing via the terminal, using various commands and combinations of commands.  sudo dpkg -i ~/Downloads/steam_latest.deb sudo apt-get update sudo apt --fix-broken install sudo apt-get install -f   In Ubuntu Software, it currently lists both "Steam" and "Steam installer" as installed applications. When I go to Steam and click "launch", nothing happens. When I open the show applications menu from the desktop and type "Steam", a program named Steam, with the Steam logo, appears. I click it; nothing happens.  How do I diagnose what is wrong?  How do I figure out why Steam is not running on my computer?  —  EDIT – in response to Organic Marble, here is the code output to the command steam—  Repairing installation, linking /home/elen/.steam/steam to /home/elen/.local/share/Steam Running Steam on ubuntu 18.04 64-bit STEAM_RUNTIME is enabled automatically Installing breakpad exception handler for appid(steam)/version(0) /home/elen/.local/share/Steam/ubuntu12_32/steam: symbol lookup error: /usr/lib/i386-linux-gnu/libxcb-dri3.so.0: undefined symbol: xcb_send_request_with_fds /home/elen/.local/share/Steam/steam.sh: line 444: no match: ssfn*

I have never used Ubuntu or any other Linux OS before last Friday. For all I know, I might have installed Ubuntu wrong and be missing a component. I would prefer if you use simplest terminology possible, but I'm OK with doing a bit of googling if need be. I just installed Steam for Ubuntu 16.04 but it won't open when I click on it in the launcher. The icon flashes for a few seconds, stops and then nothing happens. I looked in the system monitor and steam shows up there but ending the process and trying again does nothing. I heard trying to open apps that aren't working through the terminal tells you what the error is so I tried that and I got this:  Running Steam on ubuntu 16.04 64-bit STEAM_RUNTIME is enabled automatically Installing breakpad exception handler for appid(steam)/version(0) libGL error: unable to load driver: radeonsi_dri.so libGL error: driver pointer missing libGL error: failed to load driver: radeonsi libGL error: unable to load driver: swrast_dri.so libGL error: failed to load driver: swrast   Please help I just want to play CS:GO again.


I bought 17 volumes of the manga from Madman in Australia, and only recently did I get an email from them advertising an 18th volume.  I thought Vampire Knight had ended, but if volumes are still being released in Japan, then it'll take some time before they are translated and reprinted so it's ongoing. However, if it's finished in Japan then new English volumes are just catching up to the end, either way the translation is slow (I bought the 17 volumes back in March this year during a sale).  So I'm wondering: Is Vampire Knight still being written or has it finished in Japan?

I've watched the Vampire Knight anime. I really like the story so far but find it frustrating that the anime doesn't finish off the story. I'm trying to figure out if it is worth reading the manga.  Does the manga contain more story than the anime? Does it finish the story off?


the question is as follows.  $f$ is differentiable on $[a,b]$ and $f'$ is continuous. And $\forall x\in[a,b]$, f'(x) is not 0. Then, show that $$\int_a^b f(x)\,dx+ \int_{f(a)}^{f(b)} f^{-1}(x) \,dx = bf(b)-af(a)$$  I take the $$\int_{f(a)}^{f(b)} f^{-1}(x) \,dx = \int_a^b f^{-1}(f(x))f'(x) \,dx$$  I stuck here. How can i solve?

Last night, I was working on re-solidifying my understanding of parametric equations, and came up with a neat trick for evaluating certain definite integrals. I'm not sure if it exists as a formal theorem, though I refuse to believe I'm the first to notice such a relation. The 'theorem' is a useful trick to evaluate the definite integral of a continuous function over an interval where the function is either strictly increasing or strictly decreasing, given that the inverse of the function is 'nicer' to work with than the function itself. My idea goes as follows:  If $y = f(x)$ is a continuous function over the interval $I$, and either:  $f'(x) > 0$   OR   $f'(x) < 0$   for all values of $x \epsilon I$, then:  $\int_{a}^{b}{f(x)dx} = bf(b) - af(a) - \int_{f(a)}^{f(b)}{f^{-1}(x)dx}$  where $a,b \epsilon I$  Quasi-proof:  Clearly, if a function is strictly increasing or decreasing, it is injective. This is clear because no two values in the domain can correspond to a single value in the range. I feel intuitively that it must also be surjective (though I'm not entirely sure how to prove this part). Assuming it is both injective and surjective over $I$, the function must have an inverse.   If we were to draw two rectangles out of our bounds, they will have areas:  $af(a)$ and $bf(b)$, so that   $bf(b) - af(a)$ will be the area of the region we are observing.  This area is equivalent to the sum of the areas connecting the curve $f(x)$ to the $x$-axis and to the $y$-axis. Thus:  $bf(b) - af(a) = \int_{a}^{b}{f(x)dx} + \int_{f(a)}^{f(b)}{f^{-1}(x)dx}$  Solving for $\int_{a}^{b}{f(x)dx}$, we get:  $\int_{a}^{b}{f(x)dx} = bf(b) - af(a) - \int_{f(a)}^{f(b)}{f^{-1}(x)dx}$  A particularly illuminating example is evaluating:  $\int_{a}^{b}{ln(x)dx}$  $ln(x)$ is strictly increasing over any interval, so the 'theorem' applies.  $\int_{a}^{b}{ln(x)dx} = bln(b) - aln(a) - \int_{ln(a)}^{ln(b)}{e^xdx}$  $\int_{a}^{b}{ln(x)dx} = ln(b^b/a^a) - (e^{ln(b)} - e^{ln(a)})$  $\int_{a}^{b}{ln(x)dx} = ln(b^b/a^a) + a - b$  and so we've evaluated the integral without the need of integrating the function itself (by method of integration by parts), but rather by integrating its inverse, which is trivial to evaluate.!  Response to Jason DeVito's answer: [This image was taken from   ()


When I use \begin{lstlistings}, the code is too long and goes off the page, will I have to go through every line and fit it onto the page ? The code is incredibly long and this will take a very long time.    Edit: Added code:  \begin{lstlisting}[language=Python]  def bilinear_matrix(volatility,r,x0):  """Finds the bilinear form matrix A for the Black Scholes PDE"""  x = np.array(x0) N = len(x0) - 1 h = x[1:]-x[:-1]  a = np.empty(N+1) a[0] =  ((volatility**2) / 2) * ((x[1]**3 - x[0]**3) / (3 * h[0]**2)) + \         (volatility**2 - r) * (-1.0 / h[0]) * (0.5 * (1 + (x[0] / h[0])) * (x[1]**2 - x[0]**2) - ((x[1]**3 - x[0]**3) / (3 * h[0]))) \         + (r * h[0] / 3)  \end{lstlisting}

I am using the listings package to include sample Perl source code in LaTeX. I included the package with \usepackage{listings}, and used the following code:  \lstset{language=Perl} \lstset{commentstyle=\textit} \lstset{frame=shadowbox} \begin{lstlisting}[numbers=left] $subject = "<owamp:subject xmlns:owamp=\"http://ggf.org/ns/nmwg/tools/owamp/2.0/\" id=\"subject\">\n"; \end{lstlisting}   The resulting output is:    The line doesn't seem to breaking, but I read that lines break automatically when using the listings package. This line is the entire PDF snapshot of the code.  Am I doing anything wrong as far as the code is concerned?


Following on from my previous question, , I have now come across a problem regarding the timezone, and it turns out that it's not always going to be "+0200". So when strptime tries to parse it as such, it throws up an exception.  I thought about just chopping off the +0200 with [:-6] or whatever, but is there a real way to do this with strptime?  I am using Python 2.5.2 if it matters.  >>> from datetime import datetime >>> fmt = "%a, %d %b %Y %H:%M:%S +0200" >>> datetime.strptime("Tue, 22 Jul 2008 08:17:41 +0200", fmt) datetime.datetime(2008, 7, 22, 8, 17, 41) >>> datetime.strptime("Tue, 22 Jul 2008 08:17:41 +0300", fmt) Traceback (most recent call last):   File "<stdin>", line 1, in <module>   File "/usr/lib/python2.5/_strptime.py", line 330, in strptime     (data_string, format)) ValueError: time data did not match format:  data=Tue, 22 Jul 2008 08:17:41 +0300  fmt=%a, %d %b %Y %H:%M:%S +0200

I'm trying to convert a date string into an age.  The string is like: "Mon, 17 Nov 2008 01:45:32 +0200" and I need to work out how many days old it is.  I have sucessfully converted the date using:  >>> time.strptime("Mon, 17 Nov 2008 01:45:32 +0200","%a, %d %b %Y %H:%M:%S +0200") (2008, 11, 17, 1, 45, 32, 0, 322, -1)   For some reason %z gives me an error for the +0200 but it doesn't matter that much.  I can get the current time using:  >>> time.localtime() (2009, 2, 3, 19, 55, 32, 1, 34, 0)   but how can I subtract one from the other without going though each item in the list and doing it manually?


Some anonymous guy edited my answer recently. Here it is:   Five users reviewed this edit and three of them rejected it as invalid. I think that the correction is absolutely valid (missing function argument was added).  What is the correct way of bringing this edit back and accepting it?

A nice user suggested  to . The edit, though very good and desirable, was rejected. I do not understand the reasons, and I did not find a way to contact those people who rejected it. What can I do to re-approve the edit?


I use Terminator terminal. As you can see from the screenshot below, everywhere it shows the directory names. Instead of showing whole directory names, I want it to show only the last directory name i.e ecommerce in this case. Is there a way to do this?

Currently it is:   michael@Castle2012-Ubuntu-laptop01:~/Dropnot/webs/rails_v3/linker/spec/controllers$   Outside of renaming my machine and directory structure...  How could I make it be something more like:  michael:controllers$


Pardon my paranoia; but with an 80,000-strong global work force, one would think the need to cover important security guidelines for users would easily be met with each new OS X release. Yet a glance at  reveals that the last update was for 10.6 Snow Leopard, a long, long time ago for internet age.   So where are the security config guide updates for Lion, Mountain Lion & Mavericks?

Most Mac OS X releases have very nice , but Lion is not in the list. Is this document available somewhere else on Apple's site, or is there a roughly-equivalent document available somewhere on their site under another name?


I have recovered some photos with Recuva and a lot of them have been recovered fine, however there are some that only half the picture shows and the other half is just grey, then there are others that won't show a picture for the thumbnail.  When I check properties it says the size, and each picture shows a different size so I assume there is content.  Please help! If I can load the pictures up somewhere for someone to check over please let me know how and where.

Does anyone know of a way to check graphics files (particularly JPEG, GIF, and PNG) for corruption (preferably in an automated way)?    Explanation:  A few days ago, a command worked incorrectly and ended up deleting thousands of graphics files from a FAT32 volume that was practically out of space. I’ve used several different file/photo-recovery programs, but naturally, they are limited in how much they can recover (though fortunately the volume has 8KB clusters, which helps somewhat).  Anyway, some of the larger files, that were fragmented, are now corrupt. Some of them are not even real files at all (the recovery software merely dumped the clusters that were pointed to by now-overwritten directory entries), while others are broken because of fragmentation.  Moreover, because some picture formats embed a smaller version of the picture as a thumbnail, scanning the thumbnails for corruption is not reliable because it may be intact while the actual file (i.e., the picture when viewed full-size), could be corrupt.    Here are a couple of examples:      Here’s the second one. It’s so damaged that it doesn’t display anything.    (A third one wouldn’t even upload because it doesn’t even have the correct header!)


I have this script which designed to download the pronounciation of the words you give it as argument:  #!/bin/bash  m=$# for ((i=1;i<=m;i++));do  echo $i #wget https://ssl.gstatic.com/dictionary/static/sounds/de/0/"$i".mp3 done   if I run it by this command  ./a.sh personality brave selfish   it should print on the stdout  personality  brave  selfish   but instead it prints  1 2 3   would you help me solve this problem?  p.s : If I write the script without for loop with $1 for example it will work correctly but I want to download many files at the same time

I would like to write a bash script with unknown amount of arguments.  How can I walk through these arguments and do something with them?  A wrong attempt would look like this:  #!/bin/bash for i in $args; do      echo $i done


Other than the obvious "retcon!!11!" reason, was there ever an in-universe explanation about the obvious mistake the scientists made about where Abydos was actually located?  In the movie it is said that the planet is "...in another galaxy, on the other side of the observable universe."  In the series it turns out that not only is Abydos in our own galaxy, but it's in fact the closest planet to Earth with a stargate on it that can still be dialed without a DHD accounting for the stellar drift.  The writers went out of their way to explain other small inconsistencies (Ra being not "last" of his kind, but "oldest", etc.) but not this huge glaring error.

In the tie-in of SG-1 and Atlantis, they had to use a ZPM to power the gate, and use an eighth chevron to travel to the Pegasus Galaxy. It was (so I thought) common knowledge that they could only travel to gates within our own galaxy unless they had met those requirements.   Now, I recently rewatched the movie, in which the probe traveled to the Kaliam Galaxy, or as Catherine put it, "the other side of the known universe." So, why the limitation on the TV show? And why were they able to travel back to that planet in the first episodes?


I've read today a comment from a UK user that sounded weird to me:     so the OP is shooting themselves in the foot here with the tone then.   I would have said instead:     so the OP is shooting himself in the foot here with the tone then.   I've taken a look  but it's way out of my league, and appearently doesn't even answer this question.  Why did he use the third person plural while referring to a third person singular ?

Is there a pronoun I can use as a gender-neutral pronoun when referring back to a singular noun phrase?  Each student should save his questions until the end. Each student should save her questions until the end.


I have a big text file with 1,505,496 rows in the following format -  PAN     rs1  G    G  PAB     rs1  G    G  PAC     rs1  G    G  PAE     rs1  G    G  PAT     rs1  G    G  PAN     rs2  T    T  PAB     rs2  T    T  PAC     rs2  T    T  PAE     rs2  T    T  PAT     rs2  T    T  PAN     rs3  A    C  PAB     rs3  A    C  PAC     rs3  A    C  PAE     rs3  A    C  PAT     rs3  A    C  .  .    and I want my desired output to look like this:            Rs1   rs1       rs2   rs2       rs3   rs3      .... PAN        G    G          T        T       A      C PAB        G    G          T        T       A      C PAC        G    G          T        T       A      C PAE        G    G          T        T       A      C PAT        G    G          T        T       A      C   There are 1153 'rs' numbers and each 'rs' has ref and alt value (first column if each rs ref and second column is alt).

I have an CSV input file format like this, with a nucleotide sequence in field 1, text in field 2, and an integer in field 4:  ATGC,CD3,56 ATGC,CD4,67 ATGC,IgD,126 ATGC,IgM,127 AGTC,CD3,67 AGTC,CD4,78 AGTC,IgD,102 AGTC,IgM,89 TCGA,CD3,334 TCGA,CD4,123 TCGA,IgD,456 TCGA,IgM,80 CGTA,CD3,54 CGTA,CD4,32 CGTA,IgD,82 CGTA,IgM,117   I opened this CSV file using Numbers in Mac it's display as 3 columns format, however, I want to convert it to the table(or Matrix) format (also a CSV file), making the first column, the nucleotide sequences, into a header, and want the result to also look like a table (or Matrix):       ATGC  AGTC  TCGA  CGTA CD3  56    67    334   54 CD4  67    78    123   32 IgD  126   102   456   82 IgM  127   89    80    117   Below is a section from my real input CSV file (sample input.txt):  AGAATAGTCTGATTCT,-,,38 AGAATAGTCTGATTCT,AnnexinV,,51 AGAATAGTCTGATTCT,CD127,,39 AGAATAGTCTGATTCT,CD138,,3 AGAATAGTCTGATTCT,CD14,,2 AGAATAGTCTGATTCT,CD16,,4 AGAATAGTCTGATTCT,CD19,,10 AGAATAGTCTGATTCT,CD20,,6 AGAATAGTCTGATTCT,CD24,,21 AGAATAGTCTGATTCT,CD25,,4 AGAATAGTCTGATTCT,CD27,,87 AGAATAGTCTGATTCT,CD3,,235 AGAATAGTCTGATTCT,CD34,,5 AGAATAGTCTGATTCT,CD38,,18 AGAATAGTCTGATTCT,CD4,,412 AGAATAGTCTGATTCT,CD43,,99 AGAATAGTCTGATTCT,CD5,,430 AGAATAGTCTGATTCT,CD56,,3 AGAATAGTCTGATTCT,CD8,,7 AGAATAGTCTGATTCT,IgD,,4 AGAATAGTCTGATTCT,IgM,,2 TGTGGTAGTTCGTCTC,-,,9 TGTGGTAGTTCGTCTC,AnnexinV,,42 TGTGGTAGTTCGTCTC,CD127,,6 TGTGGTAGTTCGTCTC,CD138,,4 TGTGGTAGTTCGTCTC,CD16,,40 TGTGGTAGTTCGTCTC,CD19,,7 TGTGGTAGTTCGTCTC,CD20,,2 TGTGGTAGTTCGTCTC,CD24,,24 TGTGGTAGTTCGTCTC,CD25,,2   How can I do this using Linux text formatting commands?


Let's say my string is 10 characters long.   How do I remove the last character?  If my string is "abcdefghij" (I do not want to replace the 'j' character, since my string may contain multiple 'j' characters) I only want the last character gone. Regardless of what it is or how many times it occurs, I need to remove the last character from my string.

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


i have 16 gb flash drive and whenever i try to format it, the error "windows was not able to complete the format". so i tried formatting it via disk management but it still didn't work and when i tried using diskpart it encounters an error saying "the request could not be performed because of an I/O device error" and yes i did run as admin when using the cmd. Any tips on fixing this thing ?

When I plug in my USB flash drive, it shows up on my computer as write-protected or read-only. I am unable to transfer data to it, nor can I modify or delete any files already stored on it. I also cannot repartition or reformat the drive using Windows Disk Management, DiskPart, GParted, or other tools. The drive does not have a write-protect switch.  Why did this happen and what can I do about it? Is there a way to remove the write protection?  (Note that this can happen with some memory cards, too, as they often use controllers similar to those used in flash drives. In some cases, the system may report that the drive or card was formatted successfully even though it was never actually formatted; the original data reappears when the device is reinserted.)     This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this problem. Feel free to edit the answer to add additional details.


I would like to make a command to separate some blocks of text with an horizontal line.  However I don't want the line to be drawn at the end (or begininng) of a page, since the page break is already separating the content. Also it would be nice to encourage page breaks to only occur at these places.  Is there some simple way to implement this?  Here is an example. I would like to prevent the lines at the beginning of the new pages.  \documentclass{article} \usepackage{lipsum}  \newcommand{\mybreak}{    \bigskip    \pagebreak[3]   \begin{center}     --------------------------   \end{center}    \bigskip  } \begin{document}  \lipsum[1-2]  \mybreak  \lipsum[1-2]  \mybreak  \lipsum[1-2]  \mybreak  \lipsum[1-2]  \mybreak  \lipsum[1-2]  \mybreak   \end{document}

I have a manual list of stuff that are sometimes separated by an hrule(or my own custom ruler) for visual purposes.  Sometimes the hrule ends at the top or bottom of a page which makes it useless.  Is there a way to prevent it from being added if it is at the top or bottom of a page?    MWE of problem:  \documentclass{book} \usepackage{tikz} \begin{document} \newcommand\rulesep{%   \par % make sure we end a paragraph   \vskip5pt % space above the rule   \leaders\vrule width \textwidth\vskip0.4pt % rule thickness is 0.4pt   \nointerlineskip % disable interline glue here   \vskip5pt % space below the rule } \def\dotikzcircle#1{\begin{tikzpicture}\draw(0,0)circle(#1);\end{tikzpicture}} \rulesep \noindent This is a test\noindent \rulesep \noindent End of test \rulesep \dotikzcircle3 \rulesep \begin{center}\dotikzcircle3\end{center} \rulesep \begin{center}\dotikzcircle3\end{center} \rulesep \dotikzcircle1 \rulesep \dotikzcircle2 \rulesep \dotikzcircle3 \rulesep \dotikzcircle4 \rulesep \dotikzcircle5 \rulesep  \end{document}


How to make an automatically calculate of how many day from what user pick a date using datepicker and minus with the current date.   Let's say i have choosen my date using datepicker and automatically calculate for me how many days from date what i pick until todayDateTime = Now()

         Duration

         From	         To

     <input class="center" type="text" name="Dur_from" size="8"b required="yes">             	                     <input class="center" type="text" name="Dur_to" size="8" required="yes">

How do I get the number of days between two dates in JavaScript? For example, given two dates in input boxes:  <input id="first" value="1/1/2000"/> <input id="second" value="1/1/2001"/>  <script>   alert(datediff("day", first, second)); // what goes here? </script>


Find $\left(\cos 52^{\circ}+\cos 68^{\circ}+\cos 172^{\circ}\right)$      $\color{green}{a.)\ 0 }\\ b.)\ 1 \\ c.)\ 2 \\ d.)\ \text{none of these} $   In exam I often fail to remember the formula's of   $\sin(A)\pm \sin(B) \\ \cos(A)\pm \cos(B) \\ \sin(A)\pm \cos(B) \\ $  so I wonder if there is any other general method to tackle this problem.  I look for a short and simple way.  I have studied maths up to $12$th grade.  Note: I can't use calculator.

I am a little weak in trigonometry. I have two questions:   Find the value of $\cos 52^{\circ} + \cos 68^{\circ} + \cos 172^{\circ} $ Find the value of $\sin 28^{\circ}+ \cos 17^{\circ} + \cos 28^{\circ} + \sin 17^{\circ} $   I am asking these questions because: 1. I am weak and unable to solve these. 2. I want to know the difference in these questions.


Are there any cases where  x == y //false x === y //true   is that ever possible in JS? :)

I'm using  to go through JavaScript, and it's returning many suggestions to replace == (two equals signs) with === (three equals signs) when doing things like comparing idSele_UNVEHtype.value.length == 0 inside of an if statement.  Is there a performance benefit to replacing == with ===?   Any performance improvement would be welcomed as many comparison operators exist.  If no type conversion takes place, would there be a performance gain over ==?


Is the word replacement in my question is uncountable? But how?

Can't we ask instead, Have you ever had a surgery? Is surgery a countable noun? I guess we can speak of surgeries in the plural form. Why should we use zero article in this sentence?  Update: What about the phrase, You will not be emperor.  is a countable noun according to the Cambridge dictionary. Why should we use zero article in this case?


I am confused with the definition of a primary ideal. The definition states that if $R$ is a commutative ring then $I$ is called a primary ideal of $R$ is the following condition holds. If $xy\in I$ then either $x\in I$ or $y^n\in I$ for some $n$. My confusion lies in the following case. Suppose we have that $xy\in I$ but both $x$ and $y$ are not in $I$ and further $y^n \notin R\  \forall n$. Then by definition we have that $I$ is not primary. However if there exists $k$ such that $x^k\in R$ then the element $yx$ does not lead us to a contradiction. But since our ring is commutative $yx=xy$. So what I don't understand is the following this definition might show me that an ideal turns out to be primary depending on how I write the elements (i.e $xy$ or $yx$) which simply doesn't make sense. So what am I saying wrong here?  Thanks in advance.

In a commutative ring, can I say   An ideal $\mathfrak q$ in a ring $A$ is primary if $\mathfrak q \neq A $ and if $ xy \in \mathfrak q \Rightarrow $ either $ x \in \mathfrak q$ or $y^n \in \mathfrak q $ for some $n > 0$ or either $ y \in \mathfrak q$ or $x^m \in \mathfrak q $ for some $m > 0$.  Why I am asking this question is if I use the above definition, and use the ideal $P^2$ in the question , then $\bar{x}\bar{y} = \bar{z}^2 \in P^2 \text{ and } \bar x^2 \in P^2 $ gives a contradiction to the fact that $P^2$ is not primary.  Where my understanding went wrong?


I just tried doing a fresh install of the 3 flavors of Ubuntu 12.10 and every time I try to boot into the GUI interface, I face an error saying "Fatal Error: No screens detected" and then just thrown into the terminal prompt screen.  Did ubuntu discontinue support for the Intel N2600 (GMA 3600) cpu/gpu? I'm trying to install linux on a Asus EEE PC 1025C netbook.

I am looking for instructions on how to install cedarview graphics drivers on Ubuntu 13.04 32bit.  My graphics hardware is a GMA3600 aka Power VR SGX545.  EDIT: It seems that they are not in Raring yet, but only Precise:   EDIT2: they seem to be closed source.


Empirically it seems that I just gained tag wiki edit suggestion privileges (ability to add a suggestion to the review queue, not to get my changes approved without peer review) in Stack Overflow when my reputation got over 500 points. However,  suggests there is a completely different logic involved, but it doesn't seem to match my personal experience. As far as I can tell the current logic is not explained in the  or on SO's own , although there is a lot of content in both and I might have missed something. I did see somewhere a note that anyone can suggest edits to the tag wikis, but I've misplaced where that was (somewhere within the linked FAQ pages, possibly?), and at least personally I couldn't suggest tag wiki edits in SO last week when my reputation was 495. I assume that this could be one of the many cases where SO does things a bit differently than most sites, but if so, is the limit in SO truly 500 reputation or some other milestone that I happened to hit over the weekend? Edit: there was no 'Edit tag info' button at all when I tried on Friday, but now there is.

Formerly Reputation requirements compared. What are the reputation requirements for privileges on the various sites in the network? Also, how do reputation requirements for various privileges compare on different Stack Exchange sites? Specifically, the following types of sites:  Designed sites e.g. Stack Overflow, Ask Ubuntu, Gaming, etc. Public beta and non-designed sites Private beta sites  ...as well as any site-specific differences.


Just looking for some opinions here before I begin planning my next US trip.  A little background first;   I'm a UK citizen with a clean immigration history. I've made 4 short/medium length visits to the US in during 2011-2012 (on the VWP)  Visited friends in California from 18th June - 12th August 2015.  Visited same friends again from 1st November '15 - 26th January '16.   So as you can see, I spent quite a bit of time in the States last year. I should note that I received no hassle at all after visiting again in November. If anything, it was the most friendly border crossing yet!  I'm about to go through some fun stressful times with moving to a new home. After settling down in my new home for a month or so, I'm considering another vacation in the US to meet with the same friends to unwind and enjoy the California summer for around 3-4 weeks.  I was already feeling nervous about considering a trip in mid-June, considering I will have only been back in the UK for a total of 5 months before flying back out again.  However after stupidly reading a couple of online articles from people who have received hassle from CBP over too many frequent visits, I'm now even more anxious.  So here's my question to you guys. Given my recent travel history, what is your opinion about me possibly travelling again in mid-June?  I would be travelling for a much shorter duration this time, most likely just for 3-4 weeks. Obviously I realise no one can give me a 100% answer since it'll be up to the CBP officer I meet on the day, but I'm still curious to know what you guys think.  Do you think it's too soon? Or am I stressing myself out unnecessarily?   Another point to add is that on both previous visits, I ended up extending my stay by 2-3 weeks more than originally planned. (The last trip extension was due to having a heavy cold, and wanting to fight it off before flying)  Even though both trips were still within the 90 day limit, will the fact I have a history of extending my flights be an issue? (I should note that I'm not intending to do it this time)  I should note that I would be able to bring documentation in regards to my new lease to show ties to the UK, along with evidence of plenty of funds to support my trip, and a return ticket of course.  I should also note that this is the only US trip I am planning for this year.  Thanks in advance for any opinions you guys may have for me!

I went to the US for 90 days on an ESTA in August to November. Then back to my home country for 1 month and then back again mid December until mid February and now I am going back again after 10 days for another 90 days. Now I can see that some people refer to 180 day rule in a year. My stay will be 240 days in one year with short gaps between coming back. Is the 180 day rule accurate? Some people write that you can do unlimited trips to The US as long as you don't stay more than 90 days. Is that correct? My reason for going there the first time was to visit and travel with an American friend.  After my first visit (she is my girlfriend) moved with me to my home country but has ended up in a custody battle in the US so she needed to return urgently so I returned only to be with her and support her, not to be a tourist.  Then after my second visit I needed to go back to my sick Dad and to rent out my apartment since we left in a rush to go back to the US.  Now, my third visit is to continue to be with my girlfriend and support her in her difficult situation.   My question is, if I do end up in trouble should I tell them this whole story? Or should I just say I am visiting a friend for a third time because I want to see more of the country and I have some more time off before I go back to my job.  I have proof of money in my bank account and I stay and eat with her for free Documented proof that I have a job to return to in my home country My return ticket printed and an address to stay at in the US and I have proof I have an apartment in my home country


In spoken and written British English (perhaps more commonly the former), people tend to use plurals for singular organisations. For instance, "Liverpool are on top of the table", or "The Treasury are aware of the severity of the economic crisis".  Is this correct English? Or merely colloquial and local to the UK and Ireland?

I wrote a sentence for our web site that was submitted for proofreading. The proofreader "corrected" my sentence. I asked how sure he was that he was correct and that I was incorrect. He explained that there are two schools of thought on what's correct and he chose his way as the right way. I suggested that there were certainly two schools of thought: the right way and the wrong way.  School One:  There is a large number of companies.   School Two:  There are a large number of companies.    Can you tell me which is the correct school of thought and why? Update. I think I should be able to reverse the sentence and still have it makes sense.  When I attempt that, it works only with one of these sentences:  The number of companies is large. The number of companies are large.  This suggests to me that the correct sentence uses "is".  Does this make any difference?


while trying to install Ubuntu I accidentally wiped out the HDD and now my Windows 8 is gone and I'm trying to install it back whether alongside with Ubuntu or alone.  I downloaded the windows 8.1 ISO and the win-7 USB Dvd tool but of course they're .exe files so I downloaded "wine" but it didn't work and now I'm stuck with ubuntu and the files mentioned above  NOTE: I have an ultrabook so I don't have CD/DVD drive installed which means I'm only capable of using USB-stick and there's noway that this post is duplicated

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


Trying to find a movie I watched about 10 years ago, I don’t remember much of the plot, nor the title, and I’m trying to figure it out. I recall the following details:  Crane smashes into apartment building. Father is trying to find his son. Based in New York maybe? (Sphere like?) computer/AI has multiple surveillance cameras and watches everything.

Looking for a movie about the military (or intelligence agency) creating an AI system that decides to act on its own.  I do not recall the system's primary function.  Near the beginning of the movie, we see the primary operator die in a car crash.  His brother (identical twin?) is sent in, possibly to investigate, and discovers that the AI system decided to kill the brother to protect itself, and did so by changing a stop light so that he would get t-boned.  It would have been between 2000 and 2010, probably pre-2005.  I had thought maybe it was a Jake Gyllenhaal movie, but his IMDB page begs to differ.


I'm doing a cronjob task which creates a daily database backup. To desctinct the daily files, I name them as follows: dump- (the current date). The backup operation went well, but the date is not interpreted as it should be (dump-$(date '+%Y-%m-%d')) instead of dump-14-12-2018.  #filename=dump-$(date '+%Y-%m-%d') #*/3 * * * * cd /bdd-backups/ && mysqldump --all-databases >  $filename.sql -u xxx -pxxx

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


Can I take a small tube of Gorilla Glue on board a plane in my hand luggage?

Is glue something that is usually excluded from hold luggage on flights? Its a handy thing to have and I'm considering taking a 60ml tube of Gorilla glue with me.


I'm making a game that's pretty simple and I really only need to save one int for when the game is closed (the scene the payer is at), but all the tutorials and guides I've seen haven't been much help so far.   So basically I want a way to either have the game, resume right where I left off when I quit, have it load a specific scene when you resume playing, or have it save that single int. Having it load a specific scene would work best but I can use any of the options stated above.

I am making a game using the Unity game engine. I want to save the player's progress including level, experience points, chosen character, etc. Presently I am using playerprefs but I want to know whether this will work for gamers who will run this game on their mobile devices (Android/iOS) as well as desktops (OSX/PCs)? If not, then how should I save this information? I want to auto-save player progress after clearing each stage.


This was most likely somewhere between 2005 and 2010, and I saw it on a local TV station that licensed it (as the channel was in my native language but the show was in English). I realise the title is a bit vague, but that's because I only really remember three scenes:  Atop a cliff the main character is confronted by an assassin aiming to kill him. I'm sure there was a wast amount of smoke, that the character has to break through, before he jumps into the water (I think). I'm sure that the events were preceded by the local village burning during the day (possibly by the assassin).  The main character (a young man with shoulder length blonde hair) is sailing through a water filled canyon (visually similar to  from Vinland Saga) on a small boat. I remember that this was the end of the episode with a voice-over by (I think?) an old man.  This last scene may have happened just before the second scene - a giant door somewhere underground was shaking and was then broken apart from the inside. I think that there were mages/wizards trying to stop this but they couldn't.   I think that the main character was (a soon to be) mage, but being originally from a village (the one that burns in 1.). And yeah, I know all this sound as generic as a show can be, but I genuinely cannot remember anything more specific. I'm pretty sure that all these scenes happened in the same episode (or at least in sequential episodes). I know it's not  and I'm pretty sure it's not .

I'm trying to remember the name of a movie in which two young men ask a dragon three questions.  I remember that one of the men asks the dragon, "Don't we get three questions?"  The dragon responds, "Yes, but now you have only two remaining."  Or something along those lines. What movie was this from?


Books about basics of Java told some compiler behaviors. For instance in the book - OCA Oracle Certified Associate Java SE 8 Programmer I Study Guide,   Chapter 1 Java Building Blocks > Creating Objects > Constructors: For most classes, you don’t have to code a constructor—the compiler will supply a do nothing" default constructor for you. Chapter 2 Operators and Statements > Understanding Java Statements > The for Statement > The for-each Statement > Real World Scenario - Comparing for and for-each Loops: Java actually converts the for-each loop into a standard for loop during compilation   ...   All the books only told this, but they never proved it practically with some special tools. So I would like to know is it possible to see such compiler behavior by means of some tools or just programmatically so that we can drill down the explanation from the books?  I tried the javap, which listed only the public instance members with the assembly instructions. I also tried the online decompile tool , which decompiles exactly the original source code other than the intermediate code as those books told.

Is it possible to access the Abstract Syntax Tree(AST) inside the javac.exe programmatically? Could you provide an example?


Backstory:   I am running macOS Sierra and use TextEdit a lot. The problem is that I hate the Versions save schema that causes the universal Save As shortcut of CmdShiftS to instead create a copy of the document. I also hate how Auto-Save makes permanent changes to documents I don't want to modify when I'm tentatively modifying a work-in-progress. Since the introduction of these nuisance features in Lion I have always backed up and then replaced TextEdit.app with the legacy 1.6 version from Snow Leopard.  The problem:  Today when I tried to delete TextEdit.app from my Applications folder using this Terminal command  sudo rm -rf /Applications/TextEdit.app   I got this error  rm: TextEdit.app: Operation not permitted   I was surprised to find that I can't kill it, even with sudo.  How can I actually get rid of an application that is bundled with macOS?  What I've tried so far:  I followed the instructions in , but it didn't work. I also read , which almost accomplishes the same solution by means of disabling Versions and Auto-Save, but then I don't get the benefit of legacy TextEdit's temporary backup saving feature. See the part in the answer stating "This effectively disables the old-style, pre-Lion autosaving completely".   So I think deleting the newer TextEdit v1.12 and replacing it with the legacy v1.6 is still the best option, however I can't get my system to delete it. Any help appreciated.

There are some preinstalled apps that came with my laptop that I know I wil never ever use.   Apps like "Notes", "Stickies", "Game Center", etc.. that were preinstalled in my Macbook Pro are apps that I don't plan on ever using and it's taking up too much space in my Application Folder.  Are there any ways to remove them? Please note that I have already tried dragging it to the Trash bin, but it won't even go to the Trash bin. It' just stuck in my computer forever.


Inheritance (IS-A) vs. Composition (HAS-A) Relationship  please someone explaine what is Inheritance (IS-A & HAS)relationship in java

Why prefer composition over inheritance?  What trade-offs are there for each approach?  When should you choose inheritance over composition?


When a question has an open bounty on it, . Should the close link be hidden in these cases?

If a bounty is active on a question, that question . However, attempting to vote to close works just fine until the "Vote to close" button is pressed. Only then does the "this question has an active bounty and cannot be closed" message pop up.  There may be a technical reason for this, but there's no workflow reason for it. Please show the message as soon as the "close" link is clicked.


I know that there is a very similar question, but I'm not interested in highlighting. What I'm looking for is some tool in Linux to edit pdf files. I've tried pdfedit which did the work for me, but if freezes after a few edits. I've tried this tool under Ubuntu 9.10 and under KDE Fedora 14 and the same thing happens. I've tried Okular but the notations are too big to fill out exercises from pdf workbooks.    Is there any tool that suits this job? I don't care whether it is open source or I have to pay a reasonable price for it.

I typically have two needs:  Scenario A. Change a single PDF page.  In this case I have a PDF but not the original source file used to create the PDF. I don't want to try to recreate the document from scratch. I'd like to open the PDF and change a few things. A good example of this scenario: I was responsible for planning a big event at a campground site, I had a PDF of the site. I wanted to start with that document, highlight some parts, add some labels, remove some parts that weren't relevant.   or   Scenario B. Combine PDFs or extract page(s) from a PDF  This scenario usually arises because I want a single PDF deliverable that is made up of parts that are best created in different programs. In this case I have the source files for all the documents but they don't play well enough together to easily create a single PDF deliverable. For part of it, I may want to use Libre Office Writer. For another page I may want to use Gimp. Still another page I may use Libre Office Calc. I could use Writer as the master document and embed images or the Calc object into that, but for ultimate control, you can't beat separate PDF documents that are then combined.  What are the best tools / processes for editing PDFs in Ubuntu?


I just want to reboot my laptop using ubuntu 16.04LTS.After downloading it is showing to burn it to a disc,but I want to do it using a pendrive.How to do it?

I would like to see a full how-to guide on how to install Ubuntu.


I have a some text saved in a MySql database that contains a mathematical symbol. When I read this from php code it become something like this α=? and β=?  Text in database:
A round balloon of radius r subtends an angle α at the eye of the observer, while the angle of elevation of the centre is β. The height of the centre of balloon is
   Text read from php:
A round balloon of radius r subtends an angle ? at the eye of the observer, while the angle of elevation of the centre is ?. The height of the centre of balloon is
   How to solve this problem?

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


My friend from Jamaica has C1/D visa as he works on the ship. He'd like to visit me in Asia during his vacation. We are wondering if he can use the C1/D visa to transfer in JFK airport (he will need to collect his luggages and check in again tho.) or he needs to apply a transit visa?  He called the US embassy in Jamaica and they said the C1/D is from joining the ship only.  I wonder has anyone with C1/D visa successfully transit in the US?

I'm not a resident of USA. But I work on a cruise ship which required me to have C-1/D visa. I am leaving USA and traveling to Mexico but I will have a connecting flight somewhere in another US airport with 1-2 hours waiting for connecting flight to Mexico.   Do I need B1/B2 visa for that? Or my transit visa C-1/D will be enough as long as I am leaving USA?


I get this error message after trying to do the regular updates from the notification in kali linux:  E: Error http://security.kali.org/ kali/updates/main libicu48 amd64 4.8.1.1-12+deb7u2   404  Not Found   any help?

This is exact content from my sources.list:  #  # deb cdrom:[Debian GNU/Linux 2016.1 _Kali-rolling_ - Official Snapshot amd64 LIVE/INSTALL Binary 20160830-11:29]/ kali-rolling contrib main non-free #deb cdrom:[Debian GNU/Linux 2016.1 _Kali-rolling_ - Official Snapshot amd64 LIVE/INSTALL Binary 20160830-11:29]/ kali-rolling contrib main non-free   I couldn't install the Synaptic package manager and was told to modify sources.list.  I googled a lot and added some repos into it and ran update and upgrade command only to see Kali crash... I had to recover it.  Please mention the exact content that should be there to ensure that Kali Linux works.


I am trying to get the date and time on python for a program I am writing, But I am unsure how to get them. I tried to do it like the following:  import datetime import date   This usually works but now it just prints:  <module 'time' (built-in)> <module 'datetime' from 'C:\\Python34\\lib\\datetime.py'>   How can I fix this?

What is the module/method used to get the current time?


I had several print() statements in my code. I want run the code overnight and have them write to file. I tried redirecting output to file as: python mycode.py >> log.txt  While python process is running, I cannot see anything written to file. When I kill the process and open the log file, I find the output in it. Similar behavior was seen when I explicitlys specified file handle in the every print statement: output_file = open('log.txt','w') print('blablabla', file=output_file)  How can I make print to write the file immediately? Am I missing anything?

How do I force Python's print function to output to the screen?


Let H is a hilbert space of infinite dimention,  and $ V \subset H $ of finite dimention, can we show that V is closed?   I know if H is of finite dimention, then V is closed, but what if H is infinite dimention?

Let $V$ be a Hausdorff topological vector space and $Z$ a linear subspace: $Z\leq X$  Is there a neat way to prove that: $$\dim Z\text{ finite}\implies Z\text{ closed}$$


I'm often compiling stuff and therefore repeating the same command over and over, so I'd like to benefit from my "visual memory" and have a sort of "repeat last command" button attached to a terminal. More precisely, here is how I see it:   My "special" terminal would be just like a standard terminal emulator, with an extra input line at the bottom, which would have a "run" button attached to it. Clicking the button would run the command without erasing it. Maybe even an arbitrary number of such commands could be stacked (since I often need to alternate between 2 or 3 commands).   I know I can use just ↑Enter with the keyboard to redo the last command, but what often happens is that I forget I just had to type another command (to fix something, or whatever) so ↑ will not bring the right command from the history. So instead of a reflex, I have to actually read (at least skim) the command before pressing Enter.  Is there such a contraption somewhere? I often use several terminals precisely to make sure each always has the "right" command as last, but my Alt+Tab skills usually make me tab to the wrong window. And I need terminal information, such as the environment and cwd, so I cannot just try and "integrate" it in my code editor. I mean, using Alt+F2 and then Enter would not work (since I also need the read the output from the terminal). I just want to be able to use the best of both keyboard and visual memory (via clicks) at the same time.

I know I can use Up to iterate through previous commands. Running the last command simply involves Up + Enter. However, I was thinking of buying the  as I spend a lot of time in vim.  This keyboard has no arrow keys, and the only way I know how to get this kind of behaviour is by pressing Ctrl + R and beginning to repeat my previous command.  Is there an easy way to emulate Up + Enter in an UNIX terminal without the arrow keys?


so I have this math problem where I have to prove this using induction. $$\begin{pmatrix}2\\2\end{pmatrix}+\begin{pmatrix}3\\2\end{pmatrix}+\begin{pmatrix}4\\2\end{pmatrix}+\cdots+\begin{pmatrix}n\\2\end{pmatrix}=\begin{pmatrix}n+1\\3\end{pmatrix}\text{ for } n\ge2$$  I start by checking the initial case $P(2)=\begin{pmatrix}2\\2\end{pmatrix}=1$ It's good.  I then assume P(k) is true. $P(k)=\begin{pmatrix}2\\2\end{pmatrix}+\begin{pmatrix}3\\2\end{pmatrix}+\begin{pmatrix}4\\2\end{pmatrix}+\cdots+\begin{pmatrix}k\\2\end{pmatrix}=\begin{pmatrix}k+1\\3\end{pmatrix}$  I then try to prove P(k+1) is also true. $P(k+1)=\begin{pmatrix}2\\2\end{pmatrix}+\begin{pmatrix}3\\2\end{pmatrix}+\begin{pmatrix}4\\2\end{pmatrix}+\cdots+\begin{pmatrix}k+1\\2\end{pmatrix}=\begin{pmatrix}k+2\\3\end{pmatrix}$  I know that $\begin{pmatrix}k+1\\3\end{pmatrix}=\begin{pmatrix}k\\2\end{pmatrix}+\begin{pmatrix}k\\3\end{pmatrix}$  Now I'm stuck here... I'm not sure how to  finish this proof. Thanks.

Show that $\,\displaystyle\sum_{i=1}^{n} \binom{i}{2}=\binom{n+1}{3}$.   I'm thinking right now (though not getting anywhere with it) that I want to expand out the summation portion to $i!/2!(i-2)!$ and simplify from there? Not sure if that will help, not to mention if I put $1$ in for $i$ I get $1/-2$ which I don't think is right.   Anyone care to shed some light on the subject?   Thanks.


Okay, so YESTERDAY i bought my (super very wow expensive) Macbook Pro Retina 13,3". Huge investment for me. Yesterday night i tried charging i for the first time, and it started tingling against the palms of my hands whenever i like moved it across the under-keyboard area. I've read a lot about it, and i've read that it's normal, and that i have to use a three plug charger - the problem is that in Denmark we dont use three plug chargers, so i really dont know what to do! I just can't believe that i've saved so many money for so long, and that I experience problems after less than 12 hours.. ugh. Hope you can help me.

Whenever my MacBook Air is connected to the AC power and I have my hands on the palm rest, I feel it passes some electricity to me. If I unplug it from the AC power it stops doing that.  This has recently became obvious, when other people can feel this tingling by touching my skin after I've been working for a while.  I have two questions:  1- Is this normal in unibody Macs?  2- Is this harmful for my health in the long run?


I want to print an output like this:   bookId = "1234" (String)  bookName = "Machine Learning" (String)  price = $20 (int)  ratings = (array of object)     rater = a, score = 5     rater = b, score = 3   To get that output, i create the following class:  public class Shop {  private String rater; private int score; private List<Shop> ratings;  public Shop(String rater, int score) {     this.rater = rater;     this.score = score; }  // a function that contain all the data public void viewProduct() {     ratings = new ArrayList<>();      String bookId = "1234";     String bookName = "Machine Learning";     int price = $20;      Shop rater1 = new Shop("a", 5);     ratings.add(rater1);     Shop rater2 = new Shop("b", 3);     ratings.add(rater2);      // return ?   I want to return all the data from the viewProduct() function with a return syntax  But i got stuck on how to return the data, anyone can help?

I want to return two objects from a Java method and was wondering what could be a good way of doing so?  The possible ways I can think of are: return a HashMap (since the two Objects are related) or return an ArrayList of Object objects.  To be more precise, the two objects I want to return are (a) List of objects and (b) comma separated names of the same.  I want to return these two Objects from one method because I dont want to iterate through the list of objects to get the comma separated names (which I can do in the same loop in this method).  Somehow, returning a HashMap does not look a very elegant way of doing so.


I ran principal components analysis in R on my data. All my regressors are continuous, non categorical variables, except gender which I excluded. I will add it and compare model 1 = PCA to model 2 = PCA + gender and see if its significant.   I determined that PC1/2/3 determine 95% of the variance so I only consider the first 3 columns. All the variables have non-zero values and come up in the order I inputted it into the matrix of regressors.   I used a spree plot to determine I need 3 regressors to explain most of the variance only (which is rather amazing given I have 30+ variables!).  I am confused how I determine which variables I should choose. Do I order the variables per PC column from highest to lowest and see the variables contributing the most? I saw in the Freeway R guide that they actually plot the graphs and compare - similar graphs they take one variable and different looking graphs they subtract the variables from each other. This was rather confusing to me.   Questions:     Is the ANOVA approach correct in this case for this variable?  Spree plot - do I look for the first 'kink' or the point where the x axis (no of variables) first goes to 0. Mine jumps dramatically down after 3 variables (to about 0.5) and then curves down to 0 on variable 15. Different websites say different things hence I'm confused. Is the approach above correct to write a linear model? Do I write it as $y={\rm variable}_1 + {\rm variable}_2 + {\rm variable}_3$ or do I multiply them or both?

I'm new to feature selection and I was wondering how you would use PCA to perform feature selection. Does PCA compute a relative score for each input variable that you can use to filter out noninformative input variables? Basically, I want to be able to order the original features in the data by variance or amount of information contained.


I'm getting a datetime string in a format like "2009-05-28T16:15:00" (this is ISO 8601, I believe). One hackish option seems to be to parse the string using time.strptime and passing the first six elements of the tuple into the datetime constructor, like:  datetime.datetime(*time.strptime("2007-03-04T21:08:12", "%Y-%m-%dT%H:%M:%S")[:6])   I haven't been able to find a "cleaner" way of doing this. Is there one?

I need to parse  strings like "2008-09-03T20:56:35.450686Z" into Python's datetime type.  I have found  in the Python standard library, but it is not very convenient.  What is the best way to do this?


What is the Limit of $(1+\frac{1}{2})(1+\frac{1}{4})...(1+\frac{1}{2^n})$ at n = $\infty$?  At first I think it is divergent but it is surely convergent to something between $2$ and $3$. More exactly it is between $2.3$ to $2.4$. something about $2.38$. but I don't know how to find its limit. What can we say about rationality of the answer? (Is it rational or irrational?)  My question is made of two parts. first finding the limit and second, discussing about its rationality.

Compute:$$\prod_{n=1}^{\infty}\left(1+\frac{1}{2^n}\right)$$   I and my friend came across this product. Is the product till infinity equal to $1$?  If no, what is the answer?


Prove that $b\cdot\aleph_0=b$, where $b$ is an infinite set. I tried by multiplying $1\le\aleph_0\le b$ with $b$ but then I have to prove that $b\cdot b=b$  and that seems harder than my original problem.

Question:     let $\alpha$ be a infinite cardinal , show that:   $$\alpha=\aleph_{0}\alpha$$   where $\aleph_{0}$ is the cardinality of the natural numbers is denoted aleph-null   this equation is from a book,and I can't prove it,and the author say this is important equation,and can't prove it.Thank you for you help


I have some C code to practice the quick sort. I want to use macro the get the length of the array. The macro works fine in the main() function. But when I use the macro inside the sort function, it does not return the length of array. Please see the comments inside the code I left.  Also, I want to use struct to create the member function pointer called "sort" and "quick_sort". Any people who are good at c programming gives me some advise if there are some points that I can improve, not matter the syntax, the code format. I feel kind of weird about the sort and quick_sort functions format inside the struct. My purpose is use Array struct to call the functions.  #include <stdio.h> #include <stdlib.h> #include <string.h>  #define NELEMS(a) (sizeof(a) / sizeof(a[0]))  typedef struct _Array Array; struct _Array {     void (*sort)(int* arr);      void (*quick_sort)(int* arr, int l, int r); };  void sort(int* arr); void sort(int* arr) {     // Issues here.     // The len is 2 not 5.     // the macro returns the sizeof arr here is 8, not 20.     int len = NELEMS(arr);     if(len == 0){         return;     }     void quick_sort(int* arr, int l, int r);     quick_sort(arr, 0, len-1); }  void quick_sort(int* arr, int l, int r) {     int j;     if(l < r)     {         j = partition(arr, l, r);         quick_sort(arr, l, j - 1);         quick_sort(arr, j+1, r);     } }  int partition( int* a, int l, int r) {     int pivot, i, j, t;     pivot = a[l];     i = l; j = r+1;      while( 1)     {         do ++i; while( a[i] <= pivot && i <= r );         do --j; while( a[j] > pivot );         if( i >= j ) break;         t = a[i]; a[i] = a[j]; a[j] = t;     }     t = a[l]; a[l] = a[j]; a[j] = t;     return j; }  void print_array(int* array, int len){     int i;     for(i = 0; i < len; i++)         printf("%d, \n", array[i]); }  int main(int argc, char const *argv[]) {     int nums[5] = {5, 1, 3, 2, 4};     // len is 20 / 4 = 5. It works fine.     int len = NELEMS(nums);      Array *array = malloc(sizeof(Array));     array->sort = sort;     array->quick_sort = quick_sort;     sort(nums);     print_array(nums, NELEMS(nums));     return 0; }

How do I determine the size of my array in C?   That is, the number of elements the array can hold?


I have programmed in c++ for a couple of months, and I am starting to understand the core. At the moment I am trying to make a calender program with classes and inheritance (just to get more comfortable with object oriented programming), and a few weeks ago I learned about operation overloading.  I am wondering, is it a bad idea to overload parantheses for an object, such that I could for instance write this, or can an error occure becuase the compiler can confuse it for something else(constructor or something like that)?  //creating a valid year-object Year year1998 = Year(1998,true);  // the parantheses operator returns a day(another object) Day d = year1998(1,10);  //the overloading Day& Year::operator()(int monthNumber, int dayNumber){     //Just returns a day from the month class     return months[monthNumber][dayNumber]; }

I keep hearing a lot about functors in C++. Can someone give me an overview as to what they are and in what cases they would be useful?


I know that by a theorem, $A(B(x))$ is a formal power series if $b_0=0$. I wasn't sure if it works the other way around.  Can I also say that if $b_0\ne0$, $A(B(x))$ is not a formal power series?  If it doesn't work the other way around, what other techniques can I perform to determine if $A(B(x))$ is a formal power series when $b_0\ne0$?

Say if I define a power series over some arbitrary field $F$ as   $$a = \sum^{ \infty }_{i = 0} a_{i} X^{i} $$  Then can I say:  $$ab = \sum^{ \infty }_{i = 0} \sum^{ \infty }_{j = 0} a_{i} b_{j} X^{i + j} $$


I am trying to replace 'G' with 'R' but I am getting unhandled exception.  int main() {     char *pszStr1 = "EFGH";      (++pszStr1)[1] = 'R';      printf("%s", pszStr1);     return 0; }

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


I migrate an old not drupal site to drupal 9. I have a content type called "Team". This content type has some fields that the client needs a fast access/edit to all of them using a table like the old site:  Is there any module/plugin that let me do this? Or should I have to create a custom one?

I am hiding a field using hook_form_alter, because I only want to be able to edit this field in views. then, I used the  to display this field. Now, my problem is that when I press the save button, all of my nodes are saved.  Is there any way to only save nodes where this field has been edited?


Mainly error is shown in "if" section.  "org.apache.jasper.JasperException: An exception occurred processing JSP page [/enquiryForm_processing.jsp] at line [52]" is the error.  Code:  <%@page import="com.Package3.*"%>  <%String saved=EnquirySaving.savingFunction(name, address, email, mobile, gName, gMobile, time, career1, career2, career3, career4, hear1, hear2, hear3, hear4, hear5, before, institution, courses, status, councelling, visitDate, othersSpecify, othersSpecify1, othersSpecify2);%>     <%if(saved.equals("success")){%>     <%response.sendRedirect("loginPage.jsp");%> <%}else{%>     <%response.sendRedirect("enquiryForm_processing_failed.jsp");%> <%}%>

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


I wrote some conditionals for a button component and everything works, but I feel like this is not the right way of writing conditionals. Would appreciate it if anyone could review my code.  import buttonStyles from './Button.module.scss'; import { Link } from "gatsby";  interface Props {   content: string,   color: string,   path?: string,   type: string }  export default function Button(props: Props): JSX.Element {   const availableColors = ['blue', 'grey', 'dark-grey', 'white'];   const borderColors = [''];    if(!availableColors.includes(props.color)) {     console.error(`"${props.color} color key not available for button style`);     return;   }    if(!props.content) {     console.error(`"${props.content} is not valid as content`);     return;   }    let buttonStyle = buttonStyles[`button--${props.color}`];   let elementType;    if(props.type == 'link' || props.type == 'button') {     if(props.type == 'link') {       elementType = <Link to={ props.path } className={ buttonStyle }>{ props.content }</Link>     } else {       elementType = <button className={ buttonStyle }>{ props.content }</button>     }   } else {     console.error(`"${props.type} is not valid as a type. Use 'link' or 'button'`);     return;   }    return (     <React.Fragment>       { elementType }     </React.Fragment>   ); } ```

I've been trying out React for a couple of days and I tried to build a button component with some conditionals. Everything works but I feel like I am not doing it the right way. Could anyone review my code and give me some advice and tell me what I am doing wrong or what i could do better. I think I am using too many return statements. I use Typescript for type checking. Would appreciate any help! import { Link } from "gatsby";  interface Props {   content: string,   color: string,   path?: string,   type?: string }  export default function Button(props: Props): JSX.Element {   let elementType;    const checkProps = () => {     const availableColors = ['blue', 'grey', 'dark-grey', 'white'];     const borderColors = [''];     let buttonStyle;      // Check if props.color exists in availableColors     if(!availableColors.includes(props.color)) {       console.error(`"${props.color} color key not available for button style`);       return;     }          buttonStyle = buttonStyles[`button--${props.color}`];      // Check if props.content is valid     if(!props.content) {       console.error(`"${props.content} is not valid as content`);       return;     }      // Check if props.type exists     if(!props.type) {       elementType = <button className={ buttonStyle }>{ props.content }</button>       return;     }      if(props.type !== 'link') {       console.error(`"${props.type} is not a valid type, use 'link' instead or use nothing for default button`);       return;     } else {         elementType = <Link to={ props.path } className={ buttonStyle }>{ props.content }</Link>     }   }    checkProps();    return (     <React.Fragment>       { elementType }     </React.Fragment>   ); }```


I'm completely new when it comes to computational theory, and I've been asked to describe what the computational cost (as a function of n) is for a python function. I'm a bit confused on how to do this. Am I to plug in different inputs and then calculate the difference between the run time of the algorithms? And if I did that how would I describe it as a function of n? Sorry if this is a very beginner level question, I'm very new to this topic and I'd love some further explanation as well as some guidance on how to apply it to a real function using python.

Most people with a degree in CS will certainly know what . It helps us to measure how well an algorithm scales.   But I'm curious, how do you calculate or approximate the complexity of your algorithms?


I received the scene from a friend but cant seem to make it work properly in 3ds max and when exporting as fbx into Blender it seems to lose all its materials and lights?

I've tried to import but I don't see the (.max) file as an option when importing. Is there another way to import the 3DMax model into Blender for rigging and animation?


When I am posting my question I am getting the following error:     Sorry, we are no longer accepting questions from this account.   What can I do?

If you are reading this, you may have been affected by one of our post quality bans. If so, it is important that you  to understand what has happened and how to regain the permissions that you lost. While trying to ask a question, one could see:  We are no longer accepting questions from this account. See  to learn more.  Likewise, for answers:  We are no longer accepting answers from this account. See  to learn more.   Why am I getting this message? Are deleted posts taken into account too? Is a question/answer ban the same as a suspension? How do I avoid getting a question ban? How long do I have to wait before I can post again? What can I do to release the ban? How can I reactivate my account? Can I simply create a new account? I'll just ask somewhere else on the SE network, and they'll migrate my question to the correct site! Will a ban on one Stack Exchange site affect my standing on other sites in the network? Does this apply to meta sites too? My account is in good standing. Why am I still blocked?


The Structure Theorem for Finite Commutative Rings with unity state that:  A finite commutative ring $R$ with multiplication identity is isomorphic to a direct sum of local rings.  Suppose all the maximal ideals of $R$ are $M_1, M_2, ..., M_n$,  and let $J$ be the Jacobson radical of $R$. There exists a positive integer $k$ such that $J^k=0$.  There is an assertion in the proof which says that $M_i$ is the unique maximal ideal such that  $M_i^k\subseteq M_i$, why?    The complete proof of the theorem see    p. 9, lem. 9 in the thesis  p.95, thm. (VI.2) in the book "Finite rings with identity", Bernard R. McDonald p.40, thm. 3.1.4 in the article "Finite commutative rings and their applications", Gilberto Bini and Flamino Flamini

Say I have a commutative ring $R$ with a maximal ideal $m$. Then $m/m^k$ is a maximal ideal in $R/m^k$ for any $k$. Is it the only maximal ideal, i.e. is $R/m^k$ a local ring?    This is a well known result for $k = 1$, as $R/m$ is a field. It seems to be true in other cases, e.g. $p\mathbb{Z}\subset \mathbb{Z}$ for prime $p$ and for $(x,y) \subset \mathbb{F}[x,y]$, the maximal ideal generated by $x$ and $y$ in a polynomial ring over the field $\mathbb{F}$.   Equivalently, if an element $x\notin m$, is $x + m^k$ an invertible element in $R/m^k$?


I am using Ubuntu 14.04 32-bit LTS for a while and I'd love to try Ubuntu 16.04 64-bit LTS. In Ubuntu download page I found 64-bit ISO image as ubuntu-16.04-desktop-amd64.iso, I am bit confused because it mentioned amd64.  Can this image ubuntu-16.04-desktop-amd64.iso can be run on intel 64-bit processors?

What is the difference between standard i386 download and the amd64 download of Ubuntu 11.04? I am currently running the i386 on an amd machine, would my system work better with the amd64 download instead? (my machine was running Windows 7 64bit, but I neglected to look at that prior to installing Ubuntu).


I did put up a question for bounty  , which got one answer, which kinda led in the right direction, but had an immense flaw (Still in 8 Bit). I upvoted the answer cause the direction it was going is correct, but it was not totally solved, so I did not accept it. However, it was upvoted a second time, thus the bounty was auto selected in a case where the answer was not answering the question.   I know that it is not possible to withdraw a bounty which was put up once, however it feels kinda unfair to give the bounty to an unsatisfying answer.   So what could have been done better? Can a Mod change this? Or should the general behaviour of bounty questions be changed?

It's possible to offer and award bounties of reputation on questions.   What is a bounty? How can I find questions that have a bounty attached? How do I start a bounty? When can I start a bounty? Why is the system requiring me to choose a bounty amount that's higher than the minimum? Can I use Markdown formatting in the bounty remarks? Can I edit the remark? How long is the bounty period? How do I award a bounty? Can I award a bounty to my own answer? Can I award a bounty to an old answer? If I offer a bounty on someone else's question, can I award the bounty to their answer? After awarding the bounty, can I remove it or move it to another answer at a later time? What happens if there's no answer after the bounty period? What happens if I feel my question is still unanswered? What is automatic awarding? Are bounty awards exempt from the 200 points/day reputation limit? How does Community Wiki mode affect bounties? How does user deletion or post dissociation affect bounties? Can I award a bounty to an answer from a deleted user or one where the author was dissociated? Can I offer a second bounty after the first one has expired? Can I raise my bounty? What happens if a bounty question is closed or deleted? Why can't I vote to close or migrate a bounty question? What happens if I delete my account while I have an active bounty? Do I keep an awarded bounty when I delete my answer? What happens if a question where I awarded a bounty later gets deleted or migrated? Can I cancel my bounty? Can I affect / divide / share part of my bounty to two (or more) users? How many outstanding bounties can a single user have?      See also:  in the Help Center


I have some findings (new but nothing ground-breaking) from my master thesis in the field of A which I could publish if I spent more time on the topic. However, my PhD and future specialization is going to be in B. So spending time in A and particularly trying to publish in the field may be a distraction from the B. When applying for postdocs and tenured positions, is any researcher/application assessor going to appreciate my publications from a different field?  I know one mathematician from Princeton. He comes to workshops and always solves some problem. He would never publish it (even if nobody else did) because it is a distraction from what he is doing. Then other participants write his ideas and publish it with his name as coauthors. On the other hand, my personal tutor told me that any publications are good as they demonstrate the researcher's independence and capability. Hence it seems, that unless a person is a top researcher in the field, publishing in other fields is not a distraction, but a plus.

If one obtains results in one area of a field (say during an MSc thesis) before deciding that one is not interested in making a career in that area, should one take the time (as a PhD student) to get make those results publishable, or is it better to focus on the new area?


I accidentally open the second timeline widow. What's worst it is moving simultaneously with the properties tab. My question is - does anyone know how can I close this window. Here you is what my problem looks like

How do you close windows/tabs in 2.8? I've tried a lot of stuff, but always end up opening up more.


sorry if this is a basic question, but I was reading about the permutation group $S_3$, and I read that it has three subgroups: $\langle y\rangle$, $\langle xy\rangle$, $\langle x^2y\rangle$ of order 2 and $\langle x\rangle$ of order 3.   Can someone mention which subgroups these are, and how to determine their order? are any of these groups normal?

I'm being asked to find 2 subgroups of $S_3$, one of which is normal and one that isn't normal. I guess, to find the non normal subgroup is easier. I would do this by trial and error, but since the group is $S_3$ and easily visualizable, I guess that there should be a geometrical property that makes it easy to find a normal subgroup. Any of you guys know one? Or should I try this by brute force?


My teacher told me, when you pluck the string which is being stretched from two sides, it means there is tension in it. When I compress it from both ends, there is no tension in it. What does that mean?

In my textbook, the definition of tension was given that  is the reactive force which exists when string is being stretched at its both end. After it there was a case given that to calculate acceleration and tension produced in string while it's attached with different masses at both its ends and passed over a frictionless pulley. First body is being hung and second is placed over horizontal frictionless surface with relatively smaller mass. It is given in my book that there are three forces acting on the body placed on horizontal smooth surface viz., Weight of body, the reaction force to weight and tension in string pulling body towards pulley's wheel. How can there be tension in string according to the definition given my book however there is no acting force (pulling force) on the body that pulls it away from wheel.  There are different definitions for tension. The one in our book is creating problem however second one, that is, " tension describes the pulling force exerted by each end of a string, cable, chain, or similar one-dimensional continuous object " is al right.  Since acceleration is lowered due to Tension then acceleration produced in the body must be given by, $a=\frac{Net-Force}{m}$ $=>$ $a=\frac{m_1g-T}{m_1}$ since $W_1$ $>$ $T$.  If tension in string is the reactive force to the weights pulling the string apart then according to Sir Isaac Newton, $W_1=W_2=T$.


I am trying to find the possible topologies on $X=\{ a,b \}$.   $\varnothing ,\{ a,b \}$ $\varnothing ,\{ a \},\{ a,b \}$ $\varnothing ,\{ b \},\{ a,b \}$ $\varnothing ,\{ a \},\{ b \},\{ a,b \}$   First off, a topology $\tau $ on a set $X$ consists of subsets of $X$ following the properties:   The empty set $\varnothing$ and the space $X$ are both sets in the topology. The union of any collection of sets in $\tau$ is contained in $\tau$. The intersection of any finitely many sets in $\tau$ is also contained in $\tau$   All four I think are actual topologies. Am I correct?

Assuming the following: let $X$ be a set with two elements, $X$ = {$a,b$}.  what are all the possible topologies on $X$ ?  The answer I've come up with is: $$\tau_{T}=\{ \emptyset, X\} $$ $$ \tau_{a}=\{\emptyset,\{a\},X\} $$ $$\tau_{b}=\{\emptyset,\{b\},X \} $$ $$ \tau_{D}=\{\emptyset,\{a\},\{b\},X\}$$  My question is, are these correct? and are there any more?  thanks in advance


Following the advice  from , I've tried to load Ubuntu without a graphics environment by replacing quiet splash in the grub boot script with text, and alternately by appending it to the parameters.  This hasn't worked; Ubuntu 17.10 still launched the Gnome Display Manager and shows the login screen. However can I boot Ubuntu 17.10 into a terminal interface? Thank you.  For future people: Rinzwind's systemctl command works for me, while the similar systemctl command from  did not work. guiverc also points out that text as boot parameter only refers to outputting kernel messages as text, not to booting into a command line interface.

Is it possible to disable X at boot time? I'm setting up a server so it would be nice if it wouldn't load the graphical interface every time I boot.


I am using Windows 8.1 and I believe that it's been infected. I wanted to format it but I haven't backed up the files . will upgrading to windows 10 remove the virus ? Or is there any other way I can get rid of the virus..?

What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.


I own a OnePlus6 running OxygenOS 9.0.9. I noticed that lately my battery doesn't last as long as it used to. I used the Battery Monitor app to check if there's anything suspicious. This is what I noticed:     In this screenshot my battery is at 88% (12% consumed), yet, the app consumption sums up to 8% as opposed to the 12% that is actually consumed.   Is this behavior normal? Is the remaining 4% being consumed by the OS or is there some rogue app that's consuming my battery?

I use GSAM battery monitor. i have flashed a few roms,    I get this reading:   ~91% battery. 460ma current consumption with regular use(full brightness). 3:40 hours time left(avg last 5 minutes).   So this means that my 91% battery should hold around 1800mah-2000mah (460*3:40) , but this is strange because my battery is a 4100mah battery, and i have it only for 8 months.  Another strange thing: when i look at Android's battery statistics, the sum of percenatges of the battery that goes towards each app(including screen) is only at ~50%.   As a fix, i tried to recharge my phone to 0% and than fully charge. but the problem stays the same.   So what does this mean ? and are my battery problems due to software or hardware?


I need to upgrade my OS because Kubuntu 19.10 is apparently "end of life" and no longer allows updates.  The update instructions I find say apt-get update && apt-get dist-upgrade.  But apt-get update fails: Ign:1 http://us.archive.ubuntu.com/ubuntu eoan InRelease Ign:2 http://us.archive.ubuntu.com/ubuntu eoan-updates InRelease Ign:3 http://us.archive.ubuntu.com/ubuntu eoan-backports InRelease Ign:4 http://security.ubuntu.com/ubuntu eoan-security InRelease Err:5 http://us.archive.ubuntu.com/ubuntu eoan Release   404  Not Found [IP: 91.189.91.39 80] Err:6 http://security.ubuntu.com/ubuntu eoan-security Release   404  Not Found [IP: 2001:67c:1562::15 80] Err:7 http://us.archive.ubuntu.com/ubuntu eoan-updates Release   404  Not Found [IP: 91.189.91.39 80] Err:8 http://us.archive.ubuntu.com/ubuntu eoan-backports Release   404  Not Found [IP: 91.189.91.39 80] Get:9 https://download.docker.com/linux/ubuntu eoan InRelease [43.0 kB] Hit:10 http://archive.canonical.com/ubuntu eoan InRelease Hit:11 http://repository.spotify.com stable InRelease Hit:12 https://packages.riot.im/debian default InRelease Ign:13 https://dl.bintray.com/stripe/stripe-cli-deb stable InRelease Get:14 https://dl.bintray.com/stripe/stripe-cli-deb stable Release [1,840 B] Get:15 https://dl.bintray.com/stripe/stripe-cli-deb stable Release.gpg [821 B] Get:16 https://weechat.org/ubuntu eoan InRelease [3,997 B] Get:17 https://dl.bintray.com/stripe/stripe-cli-deb stable/main amd64 Packages [6,036 B] Get:18 https://weechat.org/ubuntu eoan/main Sources [3,891 B] Get:19 https://weechat.org/ubuntu eoan/main i386 Packages [4,972 B] Get:20 https://weechat.org/ubuntu eoan/main amd64 Packages [4,960 B] Reading package lists... Done E: The repository 'http://us.archive.ubuntu.com/ubuntu eoan Release' no longer has a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://security.ubuntu.com/ubuntu eoan-security Release' no longer has a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://us.archive.ubuntu.com/ubuntu eoan-updates Release' no longer has a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://us.archive.ubuntu.com/ubuntu eoan-backports Release' no longer has a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.  On too many occasions I've had apt render my computer unusable.  So I'm not willing to try apt-get dist-upgrade given that apt-get update can't even run successfully. I saw some hackish looking solution about running sed on /etc/apt/sources.list, but it was also 10 years old (not trustworthy) so I didn't try it. I can't install or update any software now.  And the first command in the upgrade in  fails.  I'm stuck.  How do I get unstuck?

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


in a file how could I select line where there is :  Value_1 and Name_species   I should get for instance:  Value_1:(O)_content_:Name_species    I tried   grep "Value_1:*:Name_species" file    but it does not work...

I don't really understand regular expressions.  Can you explain them to me in an easy-to-follow manner?  If there are any online tools or books, could you also link to them?


Currently, the profile page does not show which questions one (un-)protected.  One  (at most one week old, not containing deleted questions), but that's somewhat cumbersome. I guess it should be the point eight under the votes tab, not number nine under the actions tab, though it doesn't matter that much.

Having a record of all actions taken on a site, as is provided by the "activity" and "votes" tabs of our profile, comes in handy very often. Perhaps the most common case is being able to find a question I've interacted with in the past, to see if anything has changed about it. This applies to questions a user has protected as much as anything else. Users are theoretically encouraged to unprotect questions when it's no longer necessary, as emphasized , but in practice they often do not. In many cases it's hard to blame them: unless they specifically marked it as a favourite, the site doesn't keep any record of the question to allow them to find it again. We should help users more easily review their own protections in the future.    For personal review, the votes tab is adequate, but there may also be value in displaying this publicly in the activity tab. There may be users with a history of repeatedly protecting questions over-eagerly. It would be useful to be able to review other users' protection histories to see if this is the case. Even if this is not available to regular users, it may be helpful to moderators, unless their user activity views already allow them to filter down to see this.


In Starwars during the battle of Hoth, the empire made what i believe to be a hilarious strategic miscalculation and sent vehicles with only forward facing firepower (unimpressive firepower at that), are easy targets, and are slow moving, up against the stronger, more agile squadrons of rebel fighters which consequently result in massive imperial AT-AT casualties.   The rebels had previously illustrated a proficiency at fighter based combat and rely upon them heavily. Fighters appear to be the perfect counter to an AT-AT assault.   So why would any general in his sane mind deploy them? granted, i recognise that their firepower was sufficient to breach the rebel defences, would likely impose a significant psychological effect on the enemy, would act as overwatch due to heigh and acted as troop carriers. However they were completely vulnerable to the obvious rebel fighter counter and appear to be totally impractical anyway: They are slow moving, easy targets and possess obvious weak spots around the cockpit and leg joints.   What ever happened to tanks, which would be the far more logical alternative, especially when supported with ground to air/air-air defences, and why would the empire use AT-ATs?

are used by the Empire in a manner that is tactically identical to how a modern day army would use a tank, in that they are used as shock armour with powerful main guns which will punch through entrenched positions. (No combined arms tactics were used in the Battle of Hoth, but that's a different question altogether)  However, AT-AT walkers have a number of (rather lethal) drawbacks and no advantages that I can see compared to tanks.    They have footpads in place of treads, which greatly increase their ground pressure, and which will cause them to easily sink as compared to treads They have a high center of gravity and can be easily tripped, which was exploited in the Battle of Hoth. (granted that this was canonically presented as an oversight, albeit a rather stupid one, since most martial arts strongly emphasise lowering your CG.) They are slower than a modern main battle tank despite their long legs, which one would normally expect to grant additional mobility (max speed 60km/h on flat terrain, compared to 72km/h on flat terrain for the ). This is exacerbated by the fact that AT-AT walkers are using fusion power cells as compared to diesel engines.   It would seem that it would make far more sense for the Empire to remove the legs and mount the main chassis on treads, which would make the vehicle far more effective. Why then, did they not do this? It clearly was not the case that imperial Engineers lacked imagination, as they did produce .   Possible answers which I find implausible as advantages:  1: AT-AT walkers are tall, and therefore have a surveying advantage over the battlefield / have a better vantage point to fire from  Orbital satellites can provide the observation, and in any case air/orbital support should always be called in, especially if fire support from above is required.


‘Yeah, well, food’s one of the five exceptions to Gamp’s Law of Elemental Transfiguration,’ said Ron, to general astonishment.   Now Avis is a charm that creates a flock of birds. Isn't it possible to create the birds, and cook them to get food? Isn't this an indirect violation of the Gamp's Law of Elemental Transfiguration?

A comment on  question led me to read about the Golden Snidget on Pottermore (emphasis mine):  The Golden Snidget is an extremely rare, protected species of bird. Completely round, with a very long, thin beak and glistening, jewel-like red eyes, the Golden Snidget is an extremely fast flier that can change direction with uncanny speed and skill, owing to the rotational joints of its wings. The Golden Snidget’s feathers and eyes are so highly prized that it was at one time in danger of being hunted to extinction by wizards. The danger was recognised in time and the species protected, the most notable factor being the substitution of the Golden Snitch for the Snidget in the game of Quidditch. Snidget sanctuaries exist worldwide. - Fantastic Beasts and Where to Find Them  We see that skilled witches and wizards are easily able to transfigure inanimate things into animals:  Then [McGonagall] changed her desk into a pig and back again. They were all very impressed and couldn't wait to get started, but soon realized they weren't going to be changing the furniture into animals for a long time. - Harry Potter and the Philosopher's Stone, Chapter 8  So my question is, why would any animal (although I have provided only the Snidget as an example, I'm sure there are be more) be on the verge of extinction if it's fairly easy to perform a transfiguration and create more of them? Are there any rules or regulations in place prohibiting doing this?


I know that the lsb_release command echoes the Ubuntu version I'm currently using. But is there a command that prompts the system flavor (Ubuntu, Lubuntu, Kubuntu, Edubuntu, etc.) I'm in? Like:  $ the_command Ubuntu   If I'm using Ubuntu or  $ the_command Lubuntu   If I'm using Lubuntu?

I installed some version of Ubuntu on my VMware, but I don't know what version exactly it is. How can I find it out?


Does  only apply to web server? Or also to other servers which are  not web servers?  I ask this because in web servers, named based virtual hosts are implemented by HTTP Host header. I don't see virtual hosts for non-web servers.  Thanks.

This is a  about hostname-awareness and proxying.   I know that some protocols are hostname-aware; that is, when I connect to the HTTP server at www.example.com it knows I want www.example.com's HTTP service, not www.example.net's, even though they are on the same IP address.  How can I do this for protocol foo?  (Temporary note: this question appears pursuant to .)


\documentclass{article}  \begin{document}  \begin{description} \item[This is a very very very very very very very very very very very very very very long header line:] blah blah \end{description}  \end{document}   In the above, the item label ("This is a very ... long header line:") does not wrap. How can I make it wrap?

I have a LaTeX document that is automatically generated and then inserted as part of my own larger document with \input. This other document has a description environment for examples, one item for each. The problem is that some of them are very long and run out of the paper margins. Here's an example,  \begin{description}  \item[{\texttt{bp\_genbank\_ref\_extractor --transcripts=accession '"homo sapiens"[organism] AND H2B'}}] \mbox{}  Search Entrez gene with the query \texttt{'"homo sapiens"[organism] AND H2B'}, and save their transcripts sequences. Note that default value of \textbf{--limit} may only extract some of the hits.   \item[{\texttt{bp\_genbank\_ref\_extractor --transcripts=accession --proteins=accession --format=fasta '"homo sapiens"[organism] AND H2B' '"homo sapiens"[organism] AND MCPH1'}}] \mbox{}   Is there a way to force them to wrap around without changing the file? Something I can do before calling \input? The text there will run for several pages and is a section of the appendixes (I'm using the memoir class).  This document is generated automatically from the POD documentation of a perl script using pod2latex.


Is it possible to add a new item in a SharePoint 2010 document library using JavaScript (client object model)? I have successfully created list items in other type of lists, but when it comes to uploading a document I'm out of luck. Maybe this is a feature only supported in SharePoint 2013?  Edit: This is a working example how I add an item to a custom list. I'd like to do something similar using a document library.  var clientContext = new SP.ClientContexturl); var list = clientContext.get_web().get_lists().getByTitle('ProjectData');  clientContext.load(list);  var itemCreateInfo = new SP.ListItemCreationInformation(); var listItem = list.addItem(itemCreateInfo);  listItem.set_item('Title', 'My project title!'); listItem.update();  clientContext.load(listItem); clientContext.executeQueryAsync(onItemAdded, onItemAddedFailed);

I want to Upload File to a Document Library using JavaScript in SharePoint 2010. I found that you can copy file from One Document Library to Another but you can't upload File using JavaScript on this . I want to know exactly that is it really impossible or not. Please help me with that? Its Urgent..


Given G is a cyclic group of order $9$,Question asks to find the number of non-isomorphic subgroups of $G$.I am literally confused what exactly ask in question.Are they asking for the number of subgroups of $G$ which are non-isomorphic to $G$.Then since $G$ has exactly three subgroups of order $1,3,9$.Then subgroups of order $1,3$ must be non-isomorphic to $G$.So, I think answer is $2$.I have seen one related question asked on site and there it was given cyclic group of order $12$ and same question was asked.The answer given for that question says there are $6$ such subgroups but I got confused since $G$ is of course isomorphic to itself so remaining $5$ are non-isomorphic to $G$.Am I understanding question wrongly?

let G be a cyclic group of order 12. find number of non isomorphic subgroups of G.  How to approach such questions?