Someone needs to set the record straight on what exactly antiderivatives vary by: constants functions or piecewise constant functions.

My problem  Alright, so this is my dilemma and it all boils down to the very troublesome function floor ($\lfloor x \rfloor$) and piecewise constant functions in general ($\lfloor f(x) \rfloor$). Everyone knows what the indefinite integral is. Just in case it is not well known this is what it is:  $$F(x) = \int_{c}^{x} f(t)dt$$  The indefinite integral is an accumulation function with some base value that it starts out with. It varies by an arbitrary constant.  Now let me define a second operator that we will refer to as an implied integral ($\int^*$). It is best defined by example:  $\int^* \lfloor x \rfloor dx = x \lfloor x \rfloor + C(x)$  $\int^* x \lfloor x \rfloor dx = \frac 12 x^2 \lfloor x \rfloor + C(x)$  $\int^* \lfloor f(x) \rfloor dx = x \lfloor f(x) \rfloor + C(x)$  Basically, it is an indefinite integral that varies be piecewise constant functions (C(x)) and treats peicewise constant functions as constants.  Now,there is ambiguousness with the term "antiderivative" that I recently stumbled upon. The antiderivative seems to refer to both of these operations. For instance, see my question about the bug in matlab. The answer there claims that the implied integral is a valid antiderivative. I remember from elementary calculus that antiderivatives vary by constants. However, I am willing to give the benefit of the doubt since that user is a professor and probably knows way more than me.  Why is it important?  Well, while the area function is a set-in-stone idea differential equations rely upon use of the antiderivative and not the indefinite integral. Therefore, depending on which one the antiderivative follows... the result will change the solutions to differential equations. Specifically: It will decide whether or not their solutions must be continuous or if they are allowed to be discontinuous. A more concrete example is that we would no longer be able to just solve homogenous linear equations with constant coefficients. We would be able solve one's with piecewise constant coefficients trivially (it is possible to solve them for continuous solutions by doing things).  To sum it all up:     Do antiderivatives vary by constant functions or piecewise constant functions?   It truly is an important question.


I am in one of those annoying situations in which I try to compile a file that I compiled several times in the past (without problems), but which gives me an error message now.  Under MiKTeX, if I compile this file:  \documentclass{beamer} \begin{document} \begin{frame}   \begin{itemize}   \item P   \end{itemize} \end{frame} \end{document}   I get the error message:  ! Font OT1/mathkerncmss/m/sl/10.95=mathkerncmssi10 at 10.95pt not loadable: Met ric (TFM) file not found.  Any idea about how to get around this problem?


I am using abntex2 to write my thesis and using several tikz pictures, which leads to long compiling times.  However, I am unable to use tikzexternalize with this document class.  The system is running Ubuntu 18.04 with Texlive. It has been used to compile other documents using tikzexternalize without problems.  Texmaker is issuing the command:  latex --shell-escape -interaction=nonstopmode %.tex   A clean code that is able to reproduce my error is:  \documentclass{abntex2}  \usepackage{tikz} \usepackage{pgfplots}  \pgfplotsset{width=15cm,compat=1.9}  \usetikzlibrary{external}  \tikzexternalize[optimize command away=\includepdf]  \begin{document}     \begin{figure}[!ht]         \begin{tikzpicture}             \begin{axis}                     \addplot [samples=500,domain=0:2*pi,line width=0.5pt, black] {sin(deg(x))};             \end{axis}         \end{tikzpicture}     \end{figure} \end{document}   I have tried solutions posted on stackexchange without success.  The document compiles without any problem if the line "\tikzexternalize[optimize command away=\includepdf]" is commented out.


Drop or change automatic migration-rejection based on non-existing tags

I believe this feature creates more issues than it solves and thus would like to see it gone. (This is an out-growth of , which I repost here as it concerns several/all sites.)  The main reason why I think so is that there can be numerous reasons other than the subject being off-topic why some tag does not exist on some site, for one thing it could be a spelling, typesetting, or other formalistic reason. For example, for the two sites I know best MathOverflow and Mathematics hardly any of the most popular tags have a strictly matching tag on Mathematics but only because on MO there is the convention that certain tags are formatted in a specific way, which is not in place on Mathematics (for example nt.number-theory vs number-theory).  On top of that a user choosing the wrong site in the first place is likely not too well aware of the tags of the site they are posting too so that the question might be poorly tagged in the first place.         There is an additional detail I do not understand (it is obsolete if the actual request should be followed but in case it is not):   Even if on the source site a tag has a synonym and that synonym exists as a tag on the target site the migration is rejected. I do not understand the logic behind this at all. Possibly this is just an oversight.   I could also think of some other ways to improve the process while keeping the idea, but since I believe that it is best dropped I do not (yet) elaborate on this.


Not getting correct answers for sum of two double value

I have below program:  double tax = 180.09; double gTotal = 277.08;  double total = tax + gTotal;  System.out.println(total);   After execution it outputs 457.16999999999996.  After Google search I found that one of the cause for this behavior is that there may be no precise binary representation of the fraction part.  To verify that I tried below:  double dNum = 457.17; System.out.println(dNum);   It gave correct output as 457.17. In this case, why it is not printing 457.16999999999996.


How do Star Trek transporters stop you from being merged with stuff?

In The Wrath of Khan, Chekov beams down to a planet with a raging sandstorm. How do the transporters stop the sand from being inside him as he materialises?


Why can't my friend join the Minecraft server?

So I created a network using Hamachi, my friend joined, copied my IP from Hamachi, pasted it in direct connect, and I told him the port. He didn't write anything wrong, every number was correct. Even though we did everythnig well, he couldn't join. This is the message he got:  failed to connect to the server. io.netty.channel.AbstractChannel(dollar sign)AnnotatedConnectException:Connection refused:no further information What could go wrong?


Myself is Divya.. i am new to Linux/Unix.. i have a question on user and group management..  I read that for deleting a group a group must be empty..  I want to delete a primary group without deleting the users(as they belongs to other groups which is their secondary group)  for example I want to delete a group called ABC which contains the users U1,U2,U3,U4 whereas U1 and U4 belongs to another secondary group called DEF and GHI respectively.  ABC is the primary group for U1 and U4. let me know he command/s..  Thanks


Statistical saturation attack on block ciphers

I was wondering if anyone around here could give me some explanation on this type of attacks. Pretty much the only thing that I could find is   What I really need is basic explanation of the attack itself with a small example if possible such as any basic block cipher that you could come up with, with 3-4 rounds. This is for my personal understanding so any input is more than welcome


How to calculate the isometry group of $\mathbb{R}^n$? And show that $G$ is generated by rotations, reflections and translations? Can someone help me?


How can I reset my password without knowing my password? I tried changing my password to a longer and harder password to crack and I wrote it down in a word file but now I lost the file and I can't remember my password. Does anyone know how to reset it? I need to know as soon as possible because it's nearly 5 am and I need to close my computer but I won't be able to log back in without knowing my password.


I have one simple question: Are there any official rules regarding studying books? Any kind of books really. For example, if I spend 10 days downtime studying books does my Intelligence or Wisdom increase, or do I learn anything if I study books regarding a subject?


Is the ex-dividend date linked to the time zone of the market it is bought at? Let's imagine an American firms stock traded at NASDAQ and a German market, the ex-Dividend day being the 1st February. This announcement is made on their American website, without specifying a time zone. I want to get the dividend.  1) The German market opens at 8am on February 1st local time, which would be 2am on February 1st New York time. I sell my shares at 8am. So the trade would have been made on ex-dividend day, with NASDAQ being closed. Will I get the dividend?  2) Let's imagine a bigger time difference, where the market I sell the stock is 8am in the morning of February 1st local time, but New York Time is sill 11pm on January 31. Will I get the dividend?   Or phrased differently, is the Ex-dividend linked to a date, independent of time zones, or is it linked to a local time zone?


Difference between definitions of Rudin base vs Munkres basis

Rudin gives the definition of a base as follows in Exercise 2.23  A collection $\{V_\alpha\}$ of open subsets of $X$ is said to be a base for $X$ if the following is true: for every $x\in X$ and every open set $G\subset X$ such that $x\in G$, we have that $x\in  V_{\alpha}\subset G$ for some $\alpha$. In other words, every open set in $X$ is the union of a sub collection of $V_{\alpha}$  Munkres Topology gives the definition for a basis of a topological space as follows:  If $X$ is a set, a basis for a topology on $X$ is a collection $\mathcal{B}$ of subsets of $X$ (called basis elements) such that  For each $x\in X$, there is at least one basis element $B$ containing $x$ If $x$ belongs to the intersection of two basis elements $B_1$ and $B_2$, then there is a basis element $B_3$ containing $x$ such that $B_3\subset B_1 \cap B_2$   Are these two definitions (a base and a basis) equivalent? If so, how can I see that the Munkres's version is equivalent to the Rudin version?


How to edit ISO Images (Including Bootable ISOs)

I am looking for tools for Ubuntu that can be used to EDIT ISO Images. Including ISO images that are bootable like Ubuntu and Windows ISOs. Not only edit but save the edited ISO and can still boot when burned on an USB Drive or CD/DVD.


How to create users with limited read-only rights in Multitenant Data warehouse with one schema per tenant with views only in MS SQl server 2014

I want to create a data warehouse where data for all tenants are stored in tables under dbo schema. and now I want to create separate schema per tenant so I can create separate users. along with I wish to create views in these tenant specific schema for relevant data only. users created for these schema will have read-only rights on these schemas. Now problem occurs when I create user and grant right on their specific schema but not on dbo. as views created in any schema are reading data from dbo internaly so sql statements gets failed saying that user doesn't have permission on dbo schema. If I grant permission on dbo schema then user gets access to all data.  Can I somehow make it possible to keep data stored centralized and users created for any schema with specific access.


I'm pretty new with PDO. I'm wondering is this now safe from SQL injections?  $name = isset($_GET['name']) ? $_GET['name'] : null;  // Fetch some info $stmt = $db->prepare("SELECT * FROM players WHERE name = ? AND account_id = ?"); $stmt->execute(array($name, $aid)); $row = $stmt->fetch();  if ($row) { $stmt = $db->prepare("DELETE FROM players WHERE id = ?"); $stmt->execute(array($row['id'])); header("Location: /account"); exit(); } else { header("Location: /account"); exit(); }


2000s TV show: people stuck in primitive other world, bit of magic and bit of dinosaurs

I'm trying to identify a TV show I saw when I was a kid (I was born in 93). The show, as far as I remember, was around 2003-2005.   There were a couple of people stuck in a primitive other world. There was a husband and wife, mid 30s, an old smart dude and a young 20s guy who hooks up with one of the blonde natives who proceeds to stay with the group (at some point he disappears). They make their home base in a big tree house in a forest. There was a bit of magic and I think there was also a bit of dinosaurs.


Let $s_i=a_1+a_2+\dots+a_n$ diverge, does $\sum_{i=1}^\infty\frac{a_i}{s_i^2}$ converge?

Let $a_1,a_2\dots$ be a sequence of positive reals such that $s_n=a_1+a_2+\dots+a_n$ diverges.  Does it follow that $\sum\limits_{i=1}^\infty \frac{a_i}{s_i^2}$ converges? I am really stumped at this problem. I tried finding counterexamples like $a_n=\frac{1}{n\log n}$ and got some series which I was unsure whether they diverged or not. But at then every example I have tried converges. Thanks in advance.


How do I speed up a video by 60X in ffmpeg?

I found this example   ffmpeg -i input.mkv -filter:v "setpts=0.5*PTS" output.mkv    but I have a video I want to speed up by 60 times, not just 2X.


Where to ask tool/API/technology selection questions

I tried to ask on Stack Overflow for a tool or technology choice, and my question was closed as non-constructive or not intended for Stack Overflow. I tried to ask the same question on , and it was closed with the same reasoning.   I see that those types of questions usually have a lot of up-votes, but they are typically closed quickly. So, there exists a need for a forum where people can discuss which technology//tool to use, but I haven't found something like that yet.   Is there a place like that within the Stack Exchange Network?


Limit of sequence $ \left\{ \left(\frac{n^2+2}{2n^2+1}\right)^{n^2}\right\}_{n\geq 1}$

I trying to calculate  $$ \lim_{n\to\infty}\big(\frac{n^2+2}{2n^2+1}\big)^{n^2}.\tag{1}$$  Of course I cannot use theorem that if $a_n\to\infty$ then $\lim_{n\to\infty}(1+\frac{1}{a_n})^{a_n}=e,$ because in this particular situation we have $$\lim_{n\to\infty}\big(\frac{n^2+2}{2n^2+1}\big)^{n^2}=\lim_{n\to\infty}\big(1+\frac{1-n^2}{2n^2+1}\big)^{n^2}=\lim_{n\to\infty}\big(1+\frac{1}{\frac{(2n^2+1)}{(1-n^2)}}\big)^{n^2},$$ and $\lim_{n\to\infty}\frac{(2n^2+1)}{(1-n^2)}=-2.$  I would be grateful of any hints and comments.


How to change ubuntu install from legacy to uefi

I was not aware of booting mode and installed ubuntu on my new x64,4 gb ram, Acer ES15 laptop in legacy mode. I read about the feature of uefi mode and would like to switch to uefi. When I boot on legacy mode, ubuntu loads up and system works fine, but when I change my bios setting to uefi it says no bootable device found. Should I install ubuntu again using uefi mode after erasing data? Will that work?.... Is there any other way to get to uefi mode or I need to format and then install ubuntu again using uefi bios mode? Please, help.


Has there ever been an instance in Star Trek where someone beamed into a solid object?

One of the many notable devices in Star Trek is the transporter, which can beam people to any set coordinates. Has there ever been an instance in any Star Trek story where someone was beamed into something solid? For example, someone's arm being trapped in a table or something because they were accidentally beamed into it.


Playback HEVC videos with Plex Media Manager on LG 42LN5708 television

I'm using Plex Media Manager under Ubuntu 14.04 and want to playback HEVC videos on my LG 42LN5708 television via Plex.  HEVC videos play just fine in Mozilla Firefox when I open the Plex Media Manager program there. So apparently Plex understands what the format is. However, when I try to play the same video on my LG 42LN5708 television it says the format is not supported.  How is this possible? Plex Media Manager is just a frame server, right? So why does it not serve the frames properly to the television?


Trying to find a book about alien symbiote in a fantasy setting.  I think it was a young adult book, but I’m not sure.    People had found these aliens that they first bonded with native life and then bonded the resulting crystals to themselves giving them elementally themed powers.  There were lab flashbacks and an AI I think doing them extractions as the world regressed.  Oh yes, the humans were colonists but trapped and regressed.  The main character ends up throwing a bunch of symbiotes together in desperate attempt to beat the baddie. It might have had "storm" in the name?


Are  increases ever discrete in nature, or is it a continuous variable?  If a discrete case exists, is there any material that exhibits particularly strange behavior?


I'm unsure where to put the word "only" in the following sentence:        The machine must be operated by the authorized personnel from [company X] only.   The machine must only be operated by the authorized personnel from [company X].   The machine must be operated only by the authorized personnel from [company X].      If there's another way of saying this, let me know.


Bash script to change parent shell directory

What I'm trying to do   I've created a shell script that I've added to my $PATH that will download and get everything setup for a new  project. I would like the script to end by changing my terminal directory into the new project folder.   From what I understand right now currently it's only changing the directory of the sub shell where the script is actually running. I can't seem to figure out how to do this. Any help is appreciated. Thank you!  #! /usr/bin/env bash  echo -e '\033[1;30m=========================================='  ## check for a directory if test -z "$1"; then   echo -e ' \033[0;31m✖ Please provide a directory name'   exit fi  ## check if directory already exist if [ ! -d $1 ]; then   mkdir $1 else   echo -e ' \033[0;31m✖ The '"$1"' directory already exists'   exit fi  # move to directory cd $1  ## Download Laravel echo -e ' \033[0;32m+ \033[0mDownloading Laravel...' curl -s -L https://github.com/laravel/laravel/zipball/master > laravel.zip  ## Unzip, move, and clean up Laravel echo -e ' \033[0;32m+ \033[0mUnzipping and cleaning up files...' unzip -q laravel.zip rm laravel.zip cd *-laravel-* mv * .. cd .. rm -R *-laravel-*  ## Make the /storage directory writable echo -e ' \033[0;32m+ \033[0mMaking /storage directory writable...' chmod -R o+w storage  ## Download and install the Generators echo -e ' \033[0;32m+ \033[0mInstalling Generators...' curl -s -L https://raw.github.com/JeffreyWay/Laravel-Generator/master/generate.php > application/tasks/generate.php  ## Update the application key echo -e ' \033[0;32m+ \033[0mUpdating Application Key...' MD5=`date +”%N” | md5` sed -ie 's/YourSecretKeyGoesHere!/'"$MD5"'/' application/config/application.php rm application/config/application.phpe  ## Create .gitignore and initial git if -git is passed if [ "$2" == "-git" ]; then   echo -e ' \033[0;32m+ \033[0mInitiating git...'   touch .gitignore   curl -s -L https://raw.github.com/gist/4223565/be9f8e85f74a92c95e615ad1649c8d773e908036/.gitignore > .gitignore    # Create a local git repo   git init --quiet   git add * .gitignore   git commit -m 'Initial commit.' --quiet fi  echo -e '\033[1;30m==========================================' echo -e ' \033[0;32m✔ Laravel Setup Complete\033[0m'  ## Change parent shell directory to new directory ## Currently it's only changing in the sub shell filepath=`pwd` cd "$filepath"


How to convert dollar amounts between years?

If something cost 17 million USD in 1994 how to I figure out what it would have cost in 2000?


After json_encode() 100Ã¢ÂÂ¬ became 100Ã¢Â\u0082Â¬

I am making an api in which i fetch data which contains column some special character value when i convert them in json format it's value is change from 100Ã¢ÂÂ¬ to 100Ã¢Â\u0082Â¬ . I don't want this \u0082 extra characters .  Here is my code  $UserDetailSql    = "SELECT * FROM `characteristic` WHERE event_id='" . $events->id . "'";   //$this->_db->my_query("SET NAMES 'UTF8'");  $UserDetailSqlVal = $this->_db->my_query($UserDetailSql);  $temp_char = array();  while($characteristic = $this->_db->my_fetch_object($UserDetailSqlVal)){      $char_temp['characteristic_id'] = $characteristic->characteristic_id;       $char_temp['title_description'] = $characteristic->title;      $char = $this->_common->getEventCharacterstics($characteristic->characteristic_id);      $char_temp['title'] = $char->title;       $char_temp['image'] = IMG_PATH.'characterstics/'.$char->image;       $temp_char[] = $char_temp; } $temp['characteristic'] = $temp_char; echo json_encode($temp);`      Here $characteristic->title can have catalan or spanish or english data.The value i give in heading is this column.  I tried utf8_encode(),htmlentities(),htmlspecialcharacters() but no luck please help i am fed up now.Thanks in advance.


How to compile the document in particular orders?

\documentclass{article}  \newcommand{\reflog}[2]{\cleardoublepage    ref log --~#1 \\ #2} \newcommand{\obsform}[2]{\cleardoublepage   obs form --~#1 \\ #2} \newcommand{\lessonplan}[2]{\cleardoublepage lesson plan--~#1 \\ #2}   \begin{document}  \reflog{01 July 2015}{test test test test test } \lessonplan{01 July 2015}{test test test test test }   \obsform{02 July 2015}{test test test test test }  \reflog{03 July 2015}{test test test test test }  \lessonplan{04 July 2015}{test test test test test } \reflog{04 July 2015}{test test test test test }   \lessonplan{05 July 2015}{test test test test test }   \end{document}   If I just compile the document, it gives them in the exact order as I input them. Is there a way to say compile them according to the commands?  Say compile all \reflogs first, then \obsforms and then \lessonplan? But I still want to be able to disable this easily. So it's like an off/on switch control.  Thanks.


Using GNU-Screen for a long time.  C-a 1 2 n p   to navigate to other tabs. This works till 9. I often have 10, 11 etc. Is there any way to go to them quickly ?  Currently, i have to do:      C-a 9, C-a n which is quite a pain. Thanks.


Open the popups of all markers that are visible on the map with a zoom > 10

I need to open all the markers that are visible on the map at Zoom > 10. I am using leaflet.markercluster plugin.  Init map:  initMap() {   this.map = L.map('map', {     center: [55.55, 37.61],     zoom: 9,     layers: this.layer   })   this.tileLayer = L.tileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {     maxZoom: 18,     attribution:       '&copy; OpenStreetMap, &copy;'   })   this.tileLayer.addTo(this.map)  this.map.on('zoom', function(ev) {     ???   })   Add marker layer:  this.markerLayer = new L.LayerGroup()   // layer contain searched elements   // this.map.addLayer(this.markerLayer)    for (const i in data) { ...     const marker = new L.Marker(new L.latLng(loc), { title: title, icon: icon })// se property searched     marker.bindPopup(title)     this.markerLayer.addLayer(marker)   }   Use leaflet marker cluster:  this.markersLayer = L.markerClusterGroup({     iconCreateFunction: function(cluster) { ... },     singleMarkerMode: false   })   this.markersLayer.addLayer(this.markerLayer)   this.map.addLayer(this.markersLayer)


Best practice: card expiry date on checkout

What is the best format for gathering the card expiry data during the checkout process on an eCommerce website?  So we need to collect the month of expiry and the date of expiry (as standard on all web card transactions).  I have seen this done differently on websites so it would be good to know the best practice.


Increase close vote weight for gold tag badge holders

In order to increase the efficiency with which poor quality questions are closed, it could make sense to have weighted close votes for a small subset of qualified users.   A very good way to measure the qualified users would be to leverage the tag badges. However, it needs to be rationally limited to a set of users that are knowledgeable with the subject. A very good way to measure the top users in a tag would be to look at those who have a gold badge in the tag.  If two users who have a gold tag badge pertinent to a question issue a close vote, the question should probably be closed (or probably will be very soon under the current system). I think it would make sense to allow users with a gold tag badge to have a 3x weight for close votes in those tags.  Please keep in mind, this isn't suggesting full moderator one click closure. It only adds weight to the vote. A single user could not do it on their own. These singular users cast close votes all the time, so that aspect would not change. Some will vote to close, some wont, but the ones who do should have a stronger weight to their vote. Even with 3x it will require 2 of said votes to accomplish, or still 2 other users (meaning 3 agreed it should be closed - which is the same amount of high rep users it takes to delete a question and that has a much greater impact than closure).  tldr;  Allow gold tag badge users to have a weighted close vote in their tag


Question regarding open covers in Zariski topology (distinguished opens of affine schemes are quasi-compact)

Let $A$ be a commutative ring with $1$, and define for $f\in A$ the distinguished open set $D(f)=\{P\in\operatorname{Spec}A\mid f\not\in P\}$. Suppose we have $D(f)=\bigcup_{i\in I}D(h_i)$ over some index set $I$ and where $h_i\in A$ for every $i\in I$. I'd like to show that there is a finite subset of $I$, call it $\{1,\dots ,n\}$ for which $D(f)=\bigcup_{i=1}^n D(h_i)$. I can make some progress on this. We have $D(f)=\bigcup_{i\in I}D(h_i)$ if and only if $V(f)=\bigcap V(h_i)=V(\sum_i (h_i))$, and so $f\in\sqrt{\sum(h_i)}$, which means $f^n=\sum_{i=1}^N b_ih_i$ for some $N\geq 1$ and some $b_i\in A$. Now, how do I "get rid of" the $b_i$'s so that I can end up at the desired form?


biblatex combined with refsection and List of Tables

I have the following problem: Some Tables have captions with references in them. This works, however, when I add a List of tables (and I'm using biblatex with refsection=chapter), this reference gets messed up in the List of tables (i.e., I get ['2] instead of .  Is there a magic trick? Or can I even "hide" all the used references from captions in the List of Tables?      \documentclass{scrreprt} \usepackage[refsection=chapter]{biblatex} \usepackage[english]{babel} \usepackage[T1]{fontenc} \usepackage[ansinew]{inputenc} \begin{filecontents}{biblio.bib} @book{goossens93,     author = "Michel Goossens and Frank Mittlebach and Alexander Samarin",     title = "The Latex Companion A",     year = "1993",     publisher = "Addison-Wesley",     address = "Reading, Massachusetts"  }  @article{greenwade93,      author = "George D. Greenwade",     title = "The {C}omprehensive {T}ex {A}rchive {N}etwork ({CTAN})",     year = "1993",     journal = "TUGBoat",     volume = "14",     number = "3",     pages = "342--351",            url=" www.ctan.org" }  \end{filecontents}  \addbibresource{biblio.bib}  \begin{document} \listoftables \chapter{Test Chapter One} \cite{goossens93} \printbibliography[heading=subbibliography]  \chapter{Test Chapter Two}  \begin{table} \caption{Tabelle mit \cite{goossens93}} \centering \begin{tabular}{lll}     \hline     \textbf{linke Spalte} & \textbf{mittlere Spalte} & \textbf{rechte Spalte} \\     \hline     i & ii & iii \\     \hline \end{tabular}  \end{table}  \printbibliography[heading=subbibliography]  \end{document}


Where can I get a copy of Mavericks after Yosimite has been released?

I think I would like to install Mavericks over Snow Leopard on my Intel Core 2 Duo MacBook Pro because I imagine it is more stable than Yosimite and I'm doing a lot of development on it, for which I want Port Tree (Fink in my case) packages to be available for items like Python, PostgreSQL, etc.  But Mavericks doesn't seem to be available on the App store anymore. Tried downloading from CNET, but all I seemed to be finding was an update.  I am tempted to just install Yosemite and would love to get some input.


Baseline hazard and survival curves in Cox regression

The idea behind Cox regression in survival analysis is that it does not require knowing the baseline hazard rate, $\lambda_0(t)$. Yet, one often needs this rate, and many software packages do estimate both the baseline hazard and the baseline survival function. Question: How are the baseline hazard and/or survival function estimated? Does one reduce it to applying Kaplan-Meier estimator or is there a procedure in the spirit of Cox likelihood? To clarify: I did search the other posts, and there are many similar questions. However, they all seem to ask for a specific R or Python function for a specific package, whereas my question is about a math behind. (In order to understand the issues that I have with one such package.)


I am trying to copy fgdb from one path to another using Python.  copy(base.gdb,dest)   And got the message:  Error Info:  [Errno 13] Permission denied:   How to fix it?


Expose two filter blocks from the same view using drupal 7 ?

I'm not sure how to overcome this. So far I have managed to do it by simply duplicating the view, but this is not a good idea.   The view needs to have two exposed filters. These blocks are styled different and sit in different parts of the site, so they need to be independent.  Is it possible to expose two filter blocks from one view?


Using extension syntax I'm trying to create a left-join using LINQ on two lists that I have. The following is from the Microsoft help but I've modified it to show that the pets list has no elements. What I'm ending up with is a list of 0 elements. I assume that this is because an inner-join is taking place. What I want to end up with is a list of 3 elements (the 3 Person objects) with null data filled in for the missing elements. i.e. a Left-Join. Is this possible?  Person magnus = new Person { Name = "Hedlund, Magnus" }; Person terry = new Person { Name = "Adams, Terry" }; Person charlotte = new Person { Name = "Weiss, Charlotte" };  //Pet barley = new Pet { Name = "Barley", Owner = terry }; //Pet boots = new Pet { Name = "Boots", Owner = terry }; //Pet whiskers = new Pet { Name = "Whiskers", Owner = charlotte }; //Pet daisy = new Pet { Name = "Daisy", Owner = magnus };  List<Person> people = new List<Person> { magnus, terry, charlotte }; //List<Pet> pets = new List<Pet> { barley, boots, whiskers, daisy }; List<Pet> pets = new List<Pet>();  // Create a list of Person-Pet pairs where  // each element is an anonymous type that contains a // Pet's name and the name of the Person that owns the Pet. var query =     people.Join(pets,                 person => person,                 pet => pet.Owner,                 (person, pet) =>                     new { OwnerName = person.Name, Pet = pet.Name }).ToList();


How can I receive FM radio broadcasts on my iPhone 4?

How to listen my local FM stations in my iphone 4? Like I can listen with my old Nokia phone, without using Internet, GPRS etc.  Is iPhone 4 lacking this facility?  I heard about "Pandora Radio" but it uses the Internet to run and it's also not for Indian FM channels.  In my Nokia Express Music Mobile I can listen my local FM stations without any GPRS, Internet in mobile.


Escaping special characters like ) in regular expressions in Python

I have a dictionary and string like :  d = {'ASAP':'as soon as possible', 'AFAIK': 'as far as I know'} s = 'I will do this ASAP, AFAIK.  Regards, X'   I want to replace the values of dict with the keys of the dict in the string and return  I will do this <as soon as possible>, <as far as I know>.  Regards, X.   I use   pattern = re.compile(r'\b(' + '|'.join(d.keys())+r')\b') result=pattern.sub(lambda x: '<'+d[x.group()]+'>',s) print"result:%s" % result   I have a dictionary like:  {'will you wash some pants for me please :-)': 'text'}   The smiley is causing an error.  How do I change my regular expression to suit any characters like smileys?


How to partition my hard drive for Ubuntu use?

Till now I was windows user. From now on I want to use only Linux.   I have 500Gb HDD. How do I partition it properly? I read that there is no right or wrong way, but still, I am confused. I did something and I have primary partition mounted on / (160Gb) which I believe is a OS and 350Gb extended partition of which I have 4Gb of swap and 346Gb mounted on /home.  I got used to C:\ and D:\ partitioning, but I don't see file system in that way. I am lost. Where is what? How can I make C:\ partition for OS and D:\ for apps, movies, music, photos. Or what I want is Windows way and I have to get used to Linux way?


What is the difference, if any, between "Permanent", and "Until Dispelled"?

Some spells, such as Forbiddance, say that under certain circumstances, they last "Until Dispelled".  Other spells, such as Mordenkainen's Private Sanctum, say that under certain circumstances, they become "Permanent".  What is the difference between these two terms?  Does "Permanent" mean that the effect can never be dispelled?


forgot user password & root password 16.04

i am very user of ubuntu, i have forgot my user & root's passwords now i am not able to login in my machine. I can login via guest user. please help me to reset password.   I tried to reset the password by recovery but after 3 steps. it starts asking me for "give root password for maintenance or press control-D".   I tried with another method by pressing "e" instead of "enter" by selecting ubuntu, with linux 4.4.0-140-generic (recovery mode). But the next window something very much different.   please help !


I don't understand why people give down vote to a question even though it may not be stupid. Some don't even specify the reason for down vote. Are they doing this intentionally to reduces other's reputation? Stack Overflow should provide a facility that we can see who gave us a down vote.


Translated  I'm looking for a similar solution to creating a bat file in Windows on Ubuntu 18.04, I have a java file in which I make the call via console with the command java -jar routine.jar however I would do the same routine to streamline with an executable like in bat files.  I made a file called backup.sh with the same internal command and I applied chmod+x and made the change via Nautilus giving the execution permission via software, still it is not executed via terminal, can you help me?  Original  Estou buscando uma solução semelhante a criação de um arquivo bat no Windows no Ubuntu 18.04, eu tenho um arquivo java no qual eu faço a chamada via console com o comando java -jar rotina.jar no entanto, gostaria de fazer a mesma rotina para agilizar com um executável como em arquivos bat.  Fiz um arquivo chamado backup.sh com o mesmo comando interno e apliquei o chmod+x e fiz a alteração via Nautilus dando a permissão de execução via software, ainda assim o mesmo não é executado via terminal, podem me auxiliar?


Why does MTP show wrong directory location?

MTP (Miserable Transfer Protocol) failed once again.  After moving a directory to a different path, it is still on the same path as before according to MTP.  I already tried re-plugging the USB port and reading it from a different computer. Same result.  Why is MTP so bogus that it shows a moved folder on its previous path?


Any alternative ways to find hostels than hostelworld or hostelbookers

Are there any other reliable ways to find cheap, hostel like accommodation last minute, without using hostel world or hostel bookers?   I'm currently finding all accommodation booked up on these two sites :-\


How do I generate an audio sine or square wave of a given frequency?  I am hoping to do this to calibrate equipment, so how precise would these waves be?


Entity Framework Lookup table update / create

I had this create method:  [HttpPost] [Route("")] /// <summary> /// Create a team /// </summary> /// <param name="model">The team model</param> /// <returns>The modified team model</returns> public async Task<IHttpActionResult> Create(TeamBindingViewModel model) {      // If our model is invalid, return the errors     if (!ModelState.IsValid)         return BadRequest(ModelState);      // Get all our colours     var colours = await this.colourService.GetAllAsync();      // Create our new model     var team = new Team()     {         Name = model.Name,         Sport = model.Sport     };      // For each colour, Add to our team     team.Colours = colours.Where(m => model.Colours.Any(c => c.Id == m.Id)).ToList();      // Create our team     this.service.Create(team);      // Save our changes     await this.unitOfWork.SaveChangesAsync();      // Assign our Id to our model     model.Id = team.Id;      // Return Ok     return Ok(model); }   As you can see, when a Team is created, I need to add the Colours to the lookup table. To do this, I get the Colours from the database and then filter them by the colours that were passed as part of the model.  That tells Entity Framework that these Colours are not new entities, so it just creates a reference in the lookup table rather than creating new Colours.  Now I want to do the same for the update method.  I tried this:  [HttpPut] [Route("")] /// <summary> /// Update a team /// </summary> /// <param name="model">The team model</param> /// <returns>The modified team model</returns> public async Task<IHttpActionResult> Update(TeamBindingViewModel model) {      // If our model is invalid, return the errors     if (!ModelState.IsValid)         return BadRequest(ModelState);      // Get our current team     var team = await this.service.GetAsync(model.Id, "Colours");      // Get all our colours     var colours = await this.colourService.GetAllAsync();      // Make changes to our team     team.Name = model.Name;     team.Sport = model.Sport;      // For each colour in our team colours but not in our model colours, remove     foreach (var colour in team.Colours)         if (!model.Colours.Any(c => c.Id == colour.Id))             team.Colours.Remove(colour);      // For each colour that has to be added, add to our team colours     if (model.Colours != null)         foreach (var colour in model.Colours)             if (!team.Colours.Any(c => c.Id == colour.Id))                 team.Colours.Add(colours.Where(m => m.Id == colour.Id).SingleOrDefault());      // Update the team     this.service.Update(team);      // Save our changes     await this.unitOfWork.SaveChangesAsync();      // Return Ok     return Ok(model); }   But it didn't work. I got an error stating:          Collection was modified; enumeration operation may not execute.      I know it is talking about the Colours but I have no idea how to get around it.  Perhaps someone has had a similar problem and managed to fix it?


Maclaurin series for   $$\frac{x}{e^x-1}$$  The answer is   $$1-\frac x2 + \frac {x^2}{12} - \frac {x^4}{720} + \cdots$$  How can i get that answer?


Could Voldemort have died a natural death with his horcruxes intact?

A more general question is: Can a witch or wizard die a natural death as long as her/his horcruxes exist?  Looking for canonical answer only. Rowling's interviews etc are welcome, too.


Which one is the correct use?  She judged him wrong. She judged him wrongly.  Or, are both correct, but have slightly different meanings?


$A\in \mathrm{Mat}_n(\mathbb{Z})$ is the matrix representing $f$. Show that if $\mathrm{Coker}(f)$ is finite, then $|\det A|=|\mathrm{Coker}(f)|$.

Let $M$ be a free $\mathbb{Z}$-module of rank $n$, and $f:M\to M$ be a homomorphism of $\mathbb{Z}$-modules.  $A\in \mathrm{Mat}_n(\mathbb{Z})$ is the matrix representing $f$ with respect to a fixed $\mathbb{Z}$-basis of $M$.  Show that if $\mathrm{Coker}(f):=M/\mathrm{Im}(f)$ is finite, then $|\det A|=|\mathrm{Coker}(f)|$, and for a prime $p$ with $p\nmid |\mathrm{Coker}(f)|$ the induced map $f':M/pM\to M/pM$ is an isomorphism of  $\mathbb{Z}/(p)$-modules.


Using 2 passports Canadian/UK when visiting the UK

I will be visiting Scotland and wondered if I can use my UK passport to enter so I can use the shorter line at immigration, then use my Canadian passport when I return to Canada?


I'm trying to disable some CPUs of my server. I've found this link: , which offers me a method as below:  Here is what numactl --hardware gave me:   I want to disable all CPUs from 16 to 63, so I write a script named opCPUs.sh as below:  #!/bin/bash  for i in {16..63}; do     if [[ "$1" == "enable" ]]; then         echo 1 > /sys/devices/system/cpu/cpu$i/online     elif [[ "$1" == "disable" ]]; then         echo 0 > /sys/devices/system/cpu/cpu$i/online     else         echo 'illegal parameter'     fi done grep "processor" /proc/cpuinfo   Then I execute it: ./opCPUs.sh disable and I can see the result of grep in the script:   It seems to work.  Now I think all of processes should be in CPU 0 - 15 because others have been disabled. So I use the existing processes dbus to verify as below: ps -Lo psr $(pgrep dbus)  I get this:   The psr tells me in which CPU the process is running, right? If so, I have disabled CPU 60, CPU 52 etc, why they are still here?


Error installing Apache2 in Ubuntu 12.04

I'm new to Ubuntu, I'd installed Apache2 in Ubuntu but due to errors during installation i uninstalled it. But when i try re-installing it again an error is displayed in terminal..  Error: Module cgid does not exixts. It looks like you've deleted /etc/apache2/mods-available/cgid.load, so mod_cgid cannot be enabled.  To fix this, please purge and reinstall apache2.2-commom.  /etc/init.d/apache2: 51: .: Can't open /etc/apache2/envvars invoke-rc.d: initscript apache2, action "start" failed..   Please help me to solve this error..


What does Windows 7 'Diagnose Network' actually do (as opposed to "just check")?

I have a Linux guest virtual machine under VirtualBox, on Windows 7 Professional, which exports its disk as a Samba share.  When I connect to \\SHARENAME after booting, though, while the share does appear, and the files are there, they are greyed out with a fat grey "X" overlaid. If I click on any of them (file or folder), I'm informed that the item is not available and Windows suggests I run a Diagnose Network.  If I choose not to, and cancel, nothing happens; the share remains unavailable for up to ten minutes, after which it'll stabilize and start working for no apparent reason. During this ungrace time, connecting to the IP address, restarting Samba, twiddling with NET.EXE from command line, etc., all avail nothing.  If I accept, the Diagnose Network applet starts (d’oh), and after four or five seconds it reports that nothing is wrong. And it's right: because just an instant before it terminates, the icons become fully visible and the X overlay disappears. Nothing's wrong, but that's because it just got fixed!  So I deduce that Windows Diagnostics does something without even being aware it's doing it, to the point that it uncharacteristically doesn't even boast of having solved anything.  I'd therefore very much like to be able to run this something, whatever it is, directly from a shell script, instead of having to run the tiresome connect-doesntwork!-wannadiagnose?-yesdamnyoureyes-nothingwrongyouninny gauntlet. Or having to wait ten minutes before being able to do anything.  But what is it that Windows Diagnostics fixes, rather than just diagnosing?   Or equivalently, is there a way of making the share become "available", whatever this means?   lists what Windows Diagnostics claims to be doing, but that's not what I want. The official Microsoft answer states,     The following table contains a list of issues that the Fix My Network   Wizard can check for and fix. The list is not exhaustive, and there   are many more issues that the wizard can fix   While not claiming it's a complete list (rather, stating the contrary), the problem here is that Fix My Network can't be just checking things, it must be actively doing something, even when it doesn't say so.  More to the point, I've tried checking those same things that appear in MS's list. My checking has had no effect.  Following the advice of , I've tried the "running nbtstat -R to purge and reload the name cache" thing, with no results.  Update (and fix)  Following @DanielB's hint, I was able to fix everything by disabling Offline Availability that I must have turned on somehow on the VM's share.  My guess is that O.A. is checking every ten minutes whether the files are there or not; that if they are not, the disk is shown as unavailable, even if it meanwhile it's become available; and that Fix My Network somehow teases the check into running immediately.  So probably tinkering with Offline Availability would also have fixed my problem. This can be useful to someone with the need for O.A.; I did not have such need, so I just disabled O.A. altogether and the share now comes up at once.


what would be the null and alternative hypotheses?

In the following statement, what would be the null and alternative hypothesis? The researcher wants to test (at the 1% level), whether the true mean score is at least 5 points.  I got confused because I have learned that Ha is not supposed to have the equal sign so even if it says at least, is it okay to write this hypothesis?:  $$ H_0: \mu = 5 \\ H_a: \mu > 5 $$


How does this program create a 2D Array using malloc in C

How does the following program work to initialize a 2D Array, store data in it and then calculate the sum of all the elements. I am actually bothered about how dynamic memory allocation is actually working in this code. This approach is new to me as I couldn't find any resource that could explain this code. #include <stdio.h> #include <stdlib.h>  #define col 5 int main(){     int n, i, j, sum =0;     int (*a) [col];     printf("Enter number of rows: ");     scanf("%d", &n);     a = (int (*)[col])malloc(n * col * sizeof(int));      for(i = 0; i < n; i++){         for (j=0; j < col ; ++j){             //pointer to 5 elements row             scanf("%d", &a[i][j]);             sum+= a[i][j];         }     }      printf("Sum : %d\n",sum);      free(a);     return 0; }


Since RNA viruses and retroviruses all have high mutation rates, why do only a few viruses have the virtue of variability?

We have been taught that it's difficult to make vaccines to influenza, HIV and HCV because they lack the proofreading mechanism, hence have high mutation rates. But most RNA viruses and retroviruses are still antigenically stable, such as measles, rabies, polio, yellow fever, HBV etc. So why do only a few viruses successfully become variable? Is it because their receptors allow flexibility, or their glycoproteins have sophisticated conformations that allow more mutations?


Why does /gamerule KeepInventory true not work?

I am in minecraft 1.8.9, and when I try to do /gamerule KeepInventory true, it says the command has been updated, and then I go and do /kill. But I still lose my items, both in creative and in survival. What am I doing wrong?  @Arperum mentioned in the comments that it should be keepInventory, but on some worlds, when I type /gamerule and cycle through the rules, the one with the uppercase "K" shows up. Is that a glitch?


How long can I store homemade caramel or butterscotch sauce?

I made a butterscotch sauce for a butterbeer cupcake, but I have about a cup of the sauce left.  How long can I leave it in the fridge since it has heavy cream?  Can I freeze it?  I imagine for most purposes, caramel and butterscotch sauces will have the same storage methods.


java.lang.NullPointerException: Attempt to invoke interface method on a null object reference

the following code throws a NullPointerException and I'm not sure why. If someone could point me to the error it would be much apprecciated.   The code from the MainActivity, the error is in line 4:    private void init(){     this.createClassifier();     this.takePhoto(); }  private void createClassifier(){     try {         classifier = ImageClassifierFactory.create(                 getAssets(),                 Constants.GRAPH_FILE_PATH,                 Constants.LABELS_FILE_PATH,                 Constants.IMAGE_SIZE,                 Constants.GRAPH_INPUT_NAME,                 Constants.GRAPH_OUTPUT_NAME);     }catch (IOException e) {         Log.e("MainActivity", e.getMessage());     }   } private Classifier classifier;  ...  private final void classifyAndShowResult(final Bitmap croppedBitmap){     runInBackground((new Runnable(){         public final void run(){             Result result = classifier.recognizeImage(croppedBitmap);             showResult(result);         }     }));  }   There are different methods calling init(), so I can't figure out why classifier doesn't get initialised.   The result class:   public class Result { private String result; private float confidence;  public Result(String result, float confidence) {     this.result = result;     this.confidence = confidence; }  public String getResult() {     return result; }  public void setResult(String result) {     this.result = result; }  public float getConfidence() {     return confidence; }  public void setConfidence(float confidence) {     this.confidence = confidence; } }   the classifier Interface:   public interface Classifier { Result recognizeImage(Bitmap bitmap);   and the initiated recognizeImage:   public Result recognizeImage(Bitmap bitmap){     preprocessImageToNormalizedFloats(bitmap);     classifyImageToOutputs();     PriorityQueue outputQueue = new PriorityQueue(getResults());     Object queue = outputQueue.poll();     return (Result)queue; }   The error code was: java.lang.NullPointerException: Attempt to invoke interface method 'classifier.Result classifier.Classifier.recognizeImage(android.graphics.Bitmap)' on a null object reference  ImageClassifier Constructor:    public ImageClassifier(String inputName, String outputName, long imageSize, List labels, int[] imageBitmapPixels, float[] imageNormalizedPixels, float[] results, TensorFlowInferenceInterface tensorFlowInference) {     this.inputName = inputName;     this.outputName = outputName;     this.imageSize = imageSize;     this.labels = labels;     this.imageBitmapPixels = imageBitmapPixels;     this.imageNormalizedPixels = imageNormalizedPixels;     this.results = results;     this.tensorFlowInference = tensorFlowInference; }   ImageClassifierFactory Class:   public class ImageClassifierFactory {  public final static Classifier create(AssetManager assetManager, String graphFilePath, String labelsFilePath, int imageSize, String inputName, String outputName) throws IOException {      List labels = getLabels(assetManager, labelsFilePath);     ImageClassifier  im = new ImageClassifier(inputName, outputName, (long)imageSize, labels, new int[imageSize * imageSize], new float[imageSize * imageSize * COLOR_CHANNELS], new float[labels.size()], new TensorFlowInferenceInterface(assetManager, graphFilePath));     return im;  }   }


Getting the greatest common divisor of a sequence

For each positive integer $n$, define $a_n = 20 + n^2 $ and $d_n = \gcd(a_n, a_{n+1})$. Find the set of all values that are taken by $d_n $ and show by examples that each of these values is achievable.   Hello! I hope everybody is doing great! Can anybody help me with the above problem?  I tried some values of $n $ and I think the answer may be $1,3,9$. I thought of using $\mod 3 $ and the fact that a square is congruent to $1 \pmod{3}$ and $20 \equiv 1 \pmod{3}$ but that did not really help.  Any help would be appreciated. Thanks.


I have just searched for the usage of "until" and "by", and I was confused by these sentences. I've tried my best to tell the difference between them, and give my understanding in the bracket. Is there anybody who can tell me am I correct?   I've got to pay the money back by the end of the month. 【=pay before the end of the month】   I've got until the end of the month to pay the money back. 【=I don't need to pay it back any more, once I successfully shun the debt】   I put on an extra pair of socks. Until/By then my feet were freezing cold. 【until:my feet were no longer cold after I put on stocks】 【by:several minutes before I put on stocks I felt cold】  I stood outside the cinema for an hour. By then my feet were freezing cold. 【=in the end of the hour, my feet were cold】


Why aren't MCU movies featuring Coulson after Avengers?

Coulson died in the Avengers movie thanks to Loki, but Fury revived him in Agents of S.H.I.E.L.D. TV series. So, in-universe status of Coulson isn't a hurdle at all. He is alive and it has been explained in detail.  Talking about privacy, it barely matters if producers/writers want to. Nick Fury is also officially dead, but he'll be in Avengers: Age of Ultron.   Why exactly isn't Marvel Studios featuring Coulson in the MCU phase 2 movies? He isn't a part of Avengers: Age of Ultron crew, too.


Prove Sylvester rank inequality: $\text{rank}(AB)\ge\text{rank}(A)+\text{rank}(B)-n$

If $A$ is a $m \times n$ matrix and $B$ a $n \times k$ matrix, prove that  $$\text{rank}(AB)\ge\text{rank}(A)+\text{rank}(B)-n.$$  Also show when equality occurs.


If the number that approaches 1 from the left is 0.99 with infinitely repeating 9s, then how come 0.99 with infinitely repeating 9s equals one?

As the title says.  The proof for the last part is as follows: 1/3 = 0.333 with infinitely repeating threes. Multiplying both sides by 3, we have 1 = 0.333 with infinitely repeating threes * 3 = 0.9 with infinitely repeating 9s.  Edit:  The application for this question is with limits. Consider a function f(x) such that it defined as y = 1 for all x in [1,3].  lim f(x) x -> 1^- = DNE, since f(1^-) is not defined. But is this equation not the same as lim f(x) -> 0.99999 with infinite 9s? Since 0.99999 with infinite 9s = 1, then lim f(x) -> 0.99999 = f(1) = 1.


Are there some Latex editors that allow the online sharing? I mean an editor that when a shared file is opened by two users (for example using dropbox), each person can see on time what the other person is writing. I know that Sharelatex do it, but I would like to get an editor installed directly on my mac.


'Hardly any of us consider' or 'Hardly any of us considers'?

Any is supposed to be singular but the latter sounded kinda unidiomatic


auto enter password for `passwd ` from script?

if the script was useradd ...............<new_user>; passwd <new_user>;. is there a way to put the new password in a script? I don't need to change or add an old password for an existing user. I need to enter a brand new password twice when prompted.


Why bother publishing papers in journals?

Read this:   It says:     It is through publication that the research, including its scientific   and practical contributions, is disseminated to others in a particular   field.   Ironically, how can you disseminate research when they put a high paywall right between you and the paper?  And in today's Internet world, can't anyone just publish anywhere?


Please discourage flags on old questions and answers

The  tool is frequently cluttered with Not an answer or Low quality flags on questions and answers from 2008 and 2009; I've recently counted 17 and 13 such flagged questions or answers out of the 50 randomly shown. Stack Overflow is not the site it used to be; it doesn't seem productive to me to try to hold ancient posts to standards that did not yet exist. Some old answers should have been comments, but -- I think -- were made before comments were implemented. So I propose adding a polite unicorn when a user flags an old post:  Examples: Very Low Quality:  GEOCHET's answer is definitely lacking in description, but a -1 would probably do better than flagging. Not an Answer:   These answers, and two more, (since deleted by Robert) might have been wrong, but they were at least suggesting libraries. 2D-only, rather than the 3D that the questioner requested. That's why they had negative votes. But they weren't comments. They weren't requests for more information. They were just wrong. Incidentally, the question is a poll. Today we'd close and delete the entire question. But in 2009, it got 11 answers -- and remains open today. Duplicate:  was marked as a duplicate of . I don't think I'd ever recommend marking a question as a duplicate of a code-golf question. (Which we mostly throw over the fence these days.) But the code golf question got 8 answers back in 2009, and it remains open today. Summary Those old questions and answers might not be perfection by today's standards. But they've been picked over quite a bit already and I think we've reached the point of diminishing returns. Our flagging and pruning efforts would probably be better spent on the contents generated in the last week.


ruby introspection: how to ask ruby where a method is defined?

I have a class like this in a rails app  class User < ActiveRecord::Base   .. end   The class doesn't have a method caller foo? Nor does any of the include ... files. But User.new.foo? does respond, so how can I ask where this method is defined?


How to delete these Warehouse.jpg names from the list? I want to pack extra files, but get errors because these files don't exist  I use X sign, but no result


I don't know how I did this. Can someone explain. Is this lighting? shading? why the extreme black and how do I fix this? Thank you. Cheers!


Was Severus Snape ever loved/liked romantically by a woman?

Is there any evidence that Severus Snape from J.K. Rowling's Harry Potter was ever loved romantically by a woman? If so, please provide evidence that he was loved - canon evidence only, please.


D&D-like fantasy film from possibly the 80s

When I was a little kid I was fascinated by this movie but I only remember parts of it.  These are the little snippets I remember:   The villain was a Darth Vader-like black knight with a large sword. He had a helmet that covered half of his face. He must have had something terrible happen to him in the past. Once his helmet was removed by his superior(?) and that half of his face was all scarred. The heroes once stayed in an empty castle. In the party there was a big but good-hearted brute and a rogue-like thief. The big one was about to eat a huge bowl of chicken when the thief stopped him saying "Hey, isn't that sacred food?" The big one was like "Huh?" "Because if it is you could get sick. But I can try it for you.", and he took a bite. "Not sure yet...", and he carried on eating it until the other one realised he had been tricked. After this when they all went to bed some witch opened the front door with magic and sprayed in some spiderweb-like foam. Not sure what it did but it was bad apparently. I think the thief was running away from his hometown where a massacre took place. Probably by Darth Villain.   Not sure if this was an American film or not. I saw it on Hungarian TV in the 1980's. It wasn't Hungarian for sure.  I'm also not sure if it's a good movie or not. I loved it but I was a little kid and there weren't too many other fantasy movies.


Is the Cartesian Product of a finite number of infinitely countable sets countable?

Let $S=A_1 \times A_2 \times ...\times A_n$   Is S countable? And how do I prove it? I think the answer is yes because $A_1 \times A_2$ creates an infinite table so for n sets we would have an infinite table - just much bigger?  This is not a duplicate because no other question is for infinitely countable sets only


Why $\le$ sign rather than $<$ sign only? If $x_1<x_2 \implies f(x_1)\le f(x_2)$ then the function is increasing.

If $x_1<x_2 \implies f(x_1)\le f(x_2)$ then the function is increasing. If $x_1<x_2 \implies f(x_1)<f(x_2)$ then the function is strictly increasing. By this definition it seems that if for any $x_1<x_2 \space \space \space f(x_1)=f(x_2)$, then the function is still increasing but output values are constant. Second definition makes sense, but I don't see why would we define a function to be increasing with $\le$ sign rather than only with $< \space$?


How can I undo "always allow" in keychain item

By mistake, I clicked on "always allow" on a file in my keychain on the Mac. How do I undo this and restrict access? I tried to correct it by clicking on Access Control. There I selected "confirm before allowing access" but it didn't work. I can still see the password for that file without entering a password.


How to download software from the Ubuntu app directory?

I don't want to use sudo apt-get 'softwareName' to install software on a Ubuntu machine. Instead I want to go to  search for the software then download and install it later like Windows.  So, how to download software from Ubuntu app directory?


Is Thomae's function Riemann integrable?

Let $\displaystyle f: [0,1] \rightarrow \mathbb{R}$ given by   $$f(x) = \begin{cases} 0 & x \notin \mathbb{Q} \\ \\ 0 & x = 0 \\ \\ \frac{1}{q_x} & x = \frac{p_x}{q_x} \in \mathbb{Q} \backslash \{0\}, \ p_x \in \mathbb{Z}, \  q_x \in \mathbb{N}, \ \text{gcd}(|p_x|, q_x) = 1 \end{cases}$$  Is $\displaystyle f$ Riemann integrable?  I am trying to use the equivalent statements $\displaystyle g:[a,b] \rightarrow \mathbb{R}$ is Riemann integrable and $\displaystyle \forall \epsilon >0 \ \exists$ step functions $\displaystyle \rho, \psi$ with $\displaystyle \rho \leq g \leq \psi$ such that $\displaystyle \int_a^b (\psi - \rho) \leq \epsilon$.  I guess that means I would have to somehow show that given $\displaystyle \epsilon$, there exists only a finite amount of $\displaystyle x \in [0,1]$ with $\displaystyle f(x) \geq \epsilon$?   Is it recommended that I consider something else instead? If not, how should I do this?


The prime number theorem over a finite field - Lang's *Algebra*, Chapter V, Exercise 23(b)

This is Exercise 23(b) of Chapter V (Algebraic Extensions) from Lang's Algebra.     Let $k$ be finite field with $q$ elements, and let $\pi_q(n)$ be the number of monic irreducible polynomials $p \in k[X]$ of degree $\leq n$. Prove that   $$ \pi_q(m) \sim \frac{q}{q-1} \frac{q^m}{m} \quad \text{for} \quad m \to \infty. $$     I have tried a few things but I'm not making any progress at all.   The hint given in class was to take the logarithmic derivative of the zeta function that was defined in part (a) of the same problem. We defined the zeta function to be $$ Z(t) = (1-t)^{-1} \prod_p (1-t^{\deg p})^{-1}. $$ I computed this to be equal to the rational function $$ (1-t)^{-1}(1-qt)^{-1} $$ on the region $|t| < q^{-1}$. Taking the logarithmic derivative of $Z(t)$, I get $$ \frac{Z'(t)}{Z(t)} = \frac{1}{1-t} + \frac{q}{1-qt} = \frac{1+q-2qt}{(1-t)(1-qt)} = (1+q-2qt)Z(t). $$ I am not getting any further ideas at this point in how to use this to describe $\pi_q(n)$. From Exercise 22 I know that if $\psi(d)$ denotes the number of monic irreducible polynomials of degree $d$, then the total number of polynomials of degree $n$, which is $q^n$, can be expressed as $$ q^n = \sum_{d \mid n} d \psi(d). $$ Using the Möbius inversion formula, I can deduce that $$ n\psi(n) = \sum_{d \mid n} \mu(d) q^{n/d}, $$ where $\mu$ is the Möbius function. Since $\pi_q(m) = \sum_{k=1}^m \psi(k)$, I can use the above equation to write $$ \pi_q(m) = \sum_{k=1}^m \frac{1}{k} \sum_{d \mid k} \mu(d) q^{k/d}. $$ My intuition is that the highest power of $q$ will dominate the sum, so the RHS is approximately $$ \frac{q^m}{m}, $$ so I get roughly what I'm asked to show in the problem. I'm having trouble refining my ideas any further. I have also looked at , which asks the same problem, but no answers or comments have been posted there. Lang remarks after stating the problem, "This is the analogue of the prime number theorem in number theory, but it is essentially trivial in the present case, because the Riemann hypothesis is trivially verified." I have tried looking at the proof of the prime number theorem on the internet, but I haven't really understood it; and I certainly can't see how to deduce it from the Riemann hypothesis even in this case.   Any help in solving this problem would be appreciated.


Find all n for which $2^n$ divides $3^n-1$

Find all positive integers such that $2^n$ divides $3^n-1$.  I tried factoring $3^n-1$ as such: $$3^n-1=(3-1)(3^{n-1}+3^{n-2}+3^{n-3}+\cdots+3+1).$$ But now I'm stuck.


What are the pros and cons to keeping SQL in Stored Procs versus Code

What are the advantages/disadvantages of keeping SQL in your C# source code or in Stored Procs? I've been discussing this with a friend on an open source project that we're working on (C# ASP.NET Forum). At the moment, most of the database access is done by building the SQL inline in C# and calling to the SQL Server DB. So I'm trying to establish which, for this particular project, would be best.  So far I have:  Advantages for in Code:   Easier to maintain - don't need to run a SQL script to update queries Easier to port to another DB - no procs to port   Advantages for Stored Procs:   Performance Security


I have a null-pointer exception in fuction and don't know how to fix it

The function is:  public Integer[] details; private void putDetails(Integer l){     if (l != null){         int n = new Integer(0);         n = details[l];         details[l]=n+1;     } }   The error message say:  java.lang.NullPointerException     at operacional.an_lex.putDetails(an_lex.java:30)   where the line 30 is : n = details[l];  Can you help me?


How can I change the selected option of a select box using jQuery

As title says, how can I change the selected option of a select box using jQuery?  I have something like this:  <select id="v_lenguaje" name="lenguaje"> <option value="English">English</option> <option value="Spanish">Spanish</option> <option value="Italian">Italian</option> <option value="French">French</option> <option value="Japanese">Japanese</option> <option value=""></option> </select>   By default it shows 'English', and what i want is after an ajax call the selected option change. I tried many codes but it doesn't worked. Thanks


I have written up a script for my model. But there is a bit of a problem with it. As in I have to run the script every time I open the file. I want the script to run automatically when I open the blender File.


Quick-and-dirty way to ensure only one instance of a shell script is running at a time

What's a quick-and-dirty way to make sure that only one instance of a shell script is running at a given time?


Noetherian ring with finitely many height $n$ primes

If $R$ is a Noetherian commutative ring with unity having finitely many height one prime ideals, one could derive from the "Principal Ideal Theorem", due to Krull, that $R$ has finitely many prime ideals (all of height less than or equal to $1$). It may comes to mind that, in general,      if $R$ is a commutative Noetherian ring with unity of finite Krull dimension $d$ has finitely many prime ideals of height $n$ with $0<n≤d$, then $n=d$.    My question: is this generalization valid?   I shall appreciate any help.


We take full backups of the DB every day (in full recovery mode) and keep them for 10 days. Because of our requirements, we don't want to take incremental or differential backups of the DBs.   Now we are observing that the ldf file size is growing too large. The question, is there any way to handle this scenario?   We don't want the ldf file to increase in size but at the same time we don't want to lose full backups.


I am unable to install synaptic on my system. I have tried the following but no luck.  sudo apt-get update sudo apt-get install synaptic   I get the output:  Reading package lists... Done  Building dependency tree Reading state information... Done  Package synaptic is not available, but is referred to by another package.  This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'synaptic' has no installation candidate   This is the error message I get when I run sudo apt update :  cccc@cccc:~$ sudo apt update [sudo] password for ccccc:  Ign:1 http://gb.archive.ubuntu.com/ubuntu artful InRelease Hit:2 http://archive.canonical.com/ubuntu artful InRelease Ign:3 http://gb.archive.ubuntu.com/ubuntu artful-updates InRelease Ign:4 http://gb.archive.ubuntu.com/ubuntu artful-backports InRelease Ign:5 http://gb.archive.ubuntu.com/ubuntu artful-security InRelease Err:6 http://gb.archive.ubuntu.com/ubuntu artful Release   404  Not Found [IP: 91.189.88.149 80] Err:7 http://gb.archive.ubuntu.com/ubuntu artful-updates Release   404  Not Found [IP: 91.189.88.149 80] Err:8 http://gb.archive.ubuntu.com/ubuntu artful-backports Release   404  Not Found [IP: 91.189.88.149 80] Err:9 http://gb.archive.ubuntu.com/ubuntu artful-security Release   404  Not Found [IP: 91.189.88.149 80] Reading package lists... Done                       E: The repository 'http://gb.archive.ubuntu.com/ubuntu artful Release'  does not have 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://gb.archive.ubuntu.com/ubuntu artful-updates  Release' does not have 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://gb.archive.ubuntu.com/ubuntu artful-  backports Release' does not have 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://gb.archive.ubuntu.com/ubuntu artful-security  Release' does not have 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.   Does anyone know how to install it?


Using tags to indicate what technologies are allowed

I noticed that people use tags of technologies/languages that are not present in the actual question:    -> ,   -> , ,   -> ,    (probably all these questions:  and other question that uses similar tags with version numbers embedded)  I was tempted to remove these tags, as they are not relevant for the question and are used to attract attention (in a wrong way IMHO).  But then I was wondering whether they were added to indicate that these technologies/languages are available to answer the question...  My question/discussion is: 'Is it allowed/intended to (mis)use tags for these purposes, or should I remove them?'  Personally, I still tend to remove them, as the answer might or might not use these tags and they are (still) misused. But please correct me if I am wrong!


Convergence of series involving the prime numbers

Given the series $A=\sum\limits_{n=1}^{+\infty}\frac{p_n}{p_{n+1}}$ and $B=\sum\limits_{n=1}^{+\infty}\frac{p_{2n}}{p_{2n+1}}$, where $p_n$ is the sequence where the nth number are the nth prime number, is it possible to determine whether they are converging or diverging?   I think there are some ways using the fact that $\sum\limits_{p\in\mathbb{P}}\frac{1}{p}$ diverges, but I'm not sure of how I can use it.


I recently received an award. It's relatively prestigious (even internationally), but it's not well-known outside of my discipline, and its name is not very explicit (nor is it in English). Should I explain it on my CV? I was thinking of copying the one-sentence blurb on the award's website, something like "rewards people who have achieved this and this in this discipline". I don't see how it can hurt, but I have not seen anyone else do it...  (For context, I'm not applying for jobs as I have one, but I do apply for grants... All the time...)


Meaning of the sentence "by degrees some fifty adjuncts to that refreshment" from "Great Expectations"

From the novel Great Expectations by Charles Dickens.       I rang for the tea, and the waiter, reappearing with his magic clew, brought in by degrees some fifty adjuncts to that refreshment, but of tea not a glimpse. A teaboard, cups and saucers, plates, knives and forks (including carvers), spoons (various), saltcellars, a meek little muffin confined with the utmost precaution under a strong iron cover, Moses in the bulrushes typified by a soft bit of butter in a quantity of parsley, a pale loaf with a powdered head, two proof impressions of the bars of the kitchen fireplace on triangular bits of bread, and ultimately a fat family urn; which the waiter staggered in with, expressing in his countenance burden and suffering. After a prolonged absence at this stage of the entertainment, he at length came back with a casket of precious appearance containing twigs. These I steeped in hot water, and so from the whole of these appliances extracted one cup of I don’t know what for Estella.   Below is the sentence about which I have questions:     I rang for the tea, and the waiter, reappearing with his magic clew, brought in by degrees some fifty adjuncts to that refreshment, but of tea not a glimpse.    Does "bring in" mean "put"? Does "by degrees" mean "gradually"? Does the word "adjunct" mean "something that is joined or added to another thing but is not an essential part of it"? Does "brought in by degrees some fifty adjuncts to that refreshment" mean "gradually put fifty adjuncts in the refreshment of tea"? Does "that refreshment, but of tea not a glimpse" mean "the refreshment of tea, not the refreshment of glimpse"? Does the word "refreshment" mean "food and drink"?


Listening multiple possessives and the use of apostrophes

I want to say that 2 or more people all have something like this:  John's and Mary's hats.  Is this correct or would it have to be:  John and Mary's hats.


Charging a Macbook pro 15-inch (late 2016 touch bar)

The original charger for my laptop model can output 87W. Sometimes I forget it at work and I use my Nintendo Switch Charger (Output: 15V, 2.6A = 39W) for emergencies.  I was wondering if using a charger that may not be able to input the amount of power needed (for example maybe the laptop needs 45W so it will take the rest from the battery) could damage the laptops battery?   Extra: If there is no problem, would that also hold for this power bank:


Lie algebra of 2 by 2 matrces that are upper triangular and their characteristics that define them

I know how to find the orthogonal and the special linear group of $2$ by $2$ matrices. This is because I know their “defining” properties. How can I find the Lie algebra of:  $$A = \left(\begin{array}[c c]  - a_1 & a_2\\    0& a_1^2  \end{array}\right),$$  Where the matrices are invertible? I don’t know their defining characteristic that is my big problem. If I know it, I can use dedicated to solve. Maybe it has to do something with their matrix potential or their trace?  Please help.


I have made a car model and i'm ready to render , I decided to try to make a shadow catcher plane ( which has never worked )  Im using and HDRI image and set up the nodes correctly , yet it still doesn't work.


Understanding a proof that $2x + 3y$ is divisible by $17$ iff $9x + 5y$ is divisible by $17$

I'm having some trouble understanding a proof on  on Number Theory and I was wondering if you guys could give me some help. The problem is that I don't understand the last implication on the proof for example 1.1     Example 1.1. Let x and y be integers. Prove that 2x + 3y is divisible by 17 iff 9x + 5y is divisible by 17.      Solution. 17 | (2x + 3y) ⇒ 17 | [13(2x + 3y)], or 17 | (26x + 39y) ⇒ 17 | (9x + 5y)       conversely, 17 | (9x + 5y) ⇒ 17 | [4(9x + 5y)], or 17 | (36x + 20y) ⇒ 17 | (2x + 3y).   My problem is that I don't understand how does 17 | (26x + 39y) imply 17 | (9x + 5y). If you could elaborate on this step I would be most grateful.  I'm sorry if this is an obvious question but I am a beginner and I just can't get it.  Thanks for your help in advance.


In a five card hand how many three of a kinds can I generate?

have been trying to wrap my head around solving this. So far this is what I got. But for some reason I keep getting the wrong answer. According to some research I need the multiply the number of combinations of the last two cards(not the three of a kind) by 4 choose one * 4 choose one, and not 4 choose one. Now what I don’t understand is why do I multiply it by 4 choose one twice and not one][1][1]. [1]:  image description here]()


Let $R$ be bring, and $M$ be module over $R$. Then, we usually define krill dimension of $M$ as $dim(A/ann(M))$, where $dim()$ is krull dimension of ring. But Is this compatible with definition of krill dimension of $R$? That is, does $dim(A/ann(A))＝dimR$ always hold ? I think $ann(A)$ is not always $0$. Where am I missing? Thank you in advance.


Mobile App: browsing a tag search. Pressing back from question clears search

Steps:   Search via tag search for something Touch into a question Press system back key   Results:   Search is cleared out. Tag list displayed   Expected results:   Same search displayed prior to reading a question App Version: 1.0.95 Device Manufacturer: Samsung Device Model: SM-G950U OS Version: 7.0 (G950USQU1AQGA)


What's a word for someone whose personality or character changes a lot and get more affected than others by other's company or influential people?


Do the ranged effects of districts or the Colosseum depend on the actual district location or on the city center?

Some districts (e.g. Factories, Zoos) and the Colosseum wonder have an effect that is stated to extend to cities within a range of 6 tiles.  Will this distance be calculated from the district itself or from its city center?  example: city A is 5 tiles away from city B - does A always get all ranged effects from B's districts?  Or could districts on the far side of B fail to influence A?  Conversely, could a district on the near side of city C (itself 7+ tiles from A) influence A?


Summoning a villager with specific (Non-Custom) trades

Today I had an incident on my 1.16.4 Minecraft server where a Player had his house unnecessarily grief'd by a cheater using fly hacks. Typically in the circumstance I would give the player some of his things back, however his main concern was that of a Savannah villager who had sharpness 5. Is there any way for me to spawn a Savannah Villager with sharpness 5 for this player, and if not, is there a good plugin for future cases to make griefing easier to deal with?


Please find error in proof If c|a and c|b then $cgcd(a/c, b/c)=gcd(a, b)$

Let $R$ be UFD and denote.  Show that if  If c|a and c|b then $cgcd(a/c, b/c)=gcd(a, b)$. My attempt. Let $gcd(\frac{a}{c},\frac{b}{c})=d$. First need to show $(a,b) \subset (cd)$. This is clear since if $x \in (a,b)$ then; $$x=ar+bs=c(a/c)t+c(b/c)s$$ and since $d$ divides both $a/c$ and $b/c$ we are done. Now need to show that if $(u)$ is another princ. ideal with $(a,b) \subset (u)$ then $(cd) \subset (u)$. this is also immediate since if $y \in (cd)$ then for some $s,t \in R$ we have $(a/c)v + (b/c)w=d$ and ; $$y=cdr=c[(a/c)v + (b/c)w]r=avr+bwr$$. Which seems to show $(a,b)=(cd)$ but this can't possibly be true;


Let $A$ be ring and $\mathfrak{a}$ be an ideal of $A$. Then I was wondering whether $$\mathfrak{a}\otimes_AM \cong \mathfrak{a}M  $$ where $M$ is an $A$-module. Clearly the map $f: \mathfrak{a} \times M \to M$ defined by $f(x,y) = xy$ is surjective and bilinear so it extends to a surjective homomophism $f^{*}:\mathfrak{a}\otimes_AM \to \mathfrak{a}M$. But there is no natural inverse of $f^{*}$. It seems intuitive because $A\otimes_AM \cong M$.


Mint :give root password for maintenance

And yes: for a few days i have problems with one of systems on my PC -LMDE. Recently i got repaired there one thing as shown here : (). Now i have yet bigger problem - system ask me password for non-existing user (root) error code is here: Give root password for maintenance (or press Control-D to continue):  When i press these button it shows me: Reloading system manager configuration Starting default target You are in emergency mode. After logging in, type “journal -xb” to view system logs, “systemctl reboot” to reboot, “systemctl default” or “exit” to boot into default mode. Give root password for maintenance (or press Control-D to continue)  When i chrooted into this OS (with live-boot) i saw that there are problems with sudo and pkexec, so i cant use root even in chroot (and modify system files, etc...) is there any way to boot PC normally or i need to always use “initramfs error” and boot only to busybox cli (i can do that because i accidentally uninstalled grub and now i have cli when booting up pc)? Ps: I didnt setted up root (su) account (no password, user, etc) and i was really messing up with sudo so now i think that this also doesnt exist. ———————————————- Edit: i’ve done it with passwd as @cas said. Now i have bigger problem. My second problem is that all my partition is r/o. Even with modified /etc/fstab to open all partitions as writable. My system didn’t exited cli to the now - system doesn’t load without writable permission and my current (logged-in) user looks like root (have # before command and whoami shows me as root) but it isn’t. When i try mount command they said that i need to have root permission ( how i cant have them when currently i am root?!). Is there something i forgot, all my PC is corrupt or im a real n00b?


Who was on the audience during final battle in Rise of the Skywalker

I watched the film twice, and still, I am unsure who was on the audience during battle between Palpatine and Ray+Kylo? I thought they are some kind of ancient sith ghosts, while friend of my insist on the version, that the hooded characters are the same as the ones who repaired Kylo's helmet. (Some sort of Palpatines cult?) Is there any canonical answer to that?


I need to create an algorithm that extracts one of the largest possible  subsets from a list, in which all elements are ordered. This subset can  be non-consecutive, but must preserve the order from the original list. For example:  Input:                   Possible Output: [1,2,8,3,6,4,7,9,5]  ->  [1,2,3,6,7,9]   One might rephrase the question as "which elements do I at least have to remove so that the remaining list is sorted".  I'm not looking for an implementation, but just for ideas for a simple algorithm. My best approach so far would be to build a tree with nodes for each number, and their children being all larger numbers following in the list. Then the longest path down the tree should equal the sorted subset. However, that seems overly complicated.  Context: this is to check student's answers on a test where they have to order items by size. I want to find out for how many they got right, relative to each other.


Add the ability to lock a question against edits

(Similar to )  It would be nice if diamond mods could have the ability to prevent edits on a question/answer.    For example, the famous  answer has been (in the not recent past) defaced by a user who decided it was inappropriate.  Recently, the answer has shown up in the mod queue as flagged for the same reason.  I'd like to prevent someone from editing the answer (it is perfect), but locking it prevents people from upvoting.  The option to "prevent edits" would be nice.  Not only in this instance, but also in instances where edit wars are going on over a question/answer.


How to make the PDFs produced by pdfLaTeX smaller?

I feel that the PDFs produced by pdflatex are too huge. So for example my 50 page book with no illustrations is 500KB. I feel it should be more like 50K or even less. The .tex files together are just 40KB. Anyone knows why the final PDF is so huge and is there a way to compress it to make smaller?


I'm building a class library that will have some public & private methods. I want to be able to unit test the private methods (mostly while developing, but also it could be useful for future refactoring).  What is the correct way to do this?


If I roll two fair dice, the probability that I would get at least one 6 would be....

$11$ out of $36$? I got this by writing down the number of possible outcomes ($36$) and then counting how many of the pairs had a $6$ in them: $(1,6)$, $(2,6)$, $(3,6)$, $(4,6)$, $(5,6)$, $(6,6)$, $(6,5)$, $(6,4)$, $(6,3)$, $(6,2)$, $(6,1)$. Is this correct?


I'm building a wireless photoframe. The one thing I haven't been able to figure out is how to get my wifi connection back up using a recommended method.  Right now I edited /etc/network/interfaces so wlan0 is started at boot:  auto wlan0 iface wlan0 inet dhcp         wireless-essid ourssid   This method works fine for booting. But I found that if I do not check the connection for a long time (could be a week) it might be down. So I should reconnect.  What I do now to verify the connection is working is downloading a file from the server that can't be cached (http://server.ext/ping.php?randomize=123456) If I fail to retrieve the file I assume that the connection is no longer working and I run a shell script like  #!/bin/bash ifconfig wlan0 up iwconfig wlan0 essid "ourssid" dhclient wlan0   And the connection comes back. But I can't find anything if this is in any way a good method.  Can this be improved upon, or is this already right?


Keying and Masking Green Screen but Background Isn't Transparent

I have green screen footage that I'm trying to render with a transparent background.  I create a mask and set up my nodes in the compositer, but the result in the viewer and in renders has a checkered background with distorted colors (see image).  What is the issue? I can see and account for all nodes going into compositing, so there shouldn't be anything else. Film is set to transparent, sequencer is toggled off, and I don't have a clip editor tab open. Conceptually, I can tell that the mask and keying is working, but then it's adding back in the checkered background. I have read everything I could find and watched many tutorials.  I am out of ideas. I'm sure this is a noob mistake and I'm ready to eat crow. Thank you in advance.


Showing $\Delta(\Omega^p M)=d(\Omega^{p-1}M)\oplus \delta(\Omega^{p+1}M)$

Let $M$ be a compact Riemannian manifold, $*$ be the Hodge star operation, $d$ the exterior derivative, $\delta$ the codifferential $(\delta\omega=(-1)^{n(k+1)+1} *d*\omega$ where $n=\dim M$ and $k=\deg \omega$), and $\Delta=d\delta+\delta d $ the Laplacian operator. How can we show that $\Delta(\Omega^p M)=d(\Omega^{p-1}M)\oplus \delta(\Omega^{p+1}M)$? (Here $\Omega^pM$ denotes the space of $p$-forms on $M$.) To show this, we have to show the followings:  $d(\Omega^{p-1}M)\subset \Delta(\Omega^pM)$ and $\delta(\Omega^{p+1}M)\subset \Delta(\Omega^pM)$,  $d(\Omega^{p-1}M)\cap \delta(\Omega^{p+1}M)=0$, and  $d(\Omega^{p-1}M)+\delta(\Omega^{p+1}M)=\Delta(\Omega^pM)$.   The third one is obvious by definition of $\Delta$. The second one follows from the fact that they are orthogonal. But how can we show 1?


When a ship is under attack, the shields wear down over the course of the attack.  What is the mechanism behind this? Aren't the shields powered using energy? While the ship has energy, shouldn't it be able to indefinitely defend against attacks the shield can absorb?


What happens when I use [::-1] with a variable?

So I have this code: t=int(input()) while t:  s=int(input())  n=bin(s)  n=n[2:][::-1]  if n.count('1')==1:   pos=n.find('1')+1   print(pos) else:   print('-1') t-=1  I would like to know exactly what's going on in this line:  n=n[2:][::-1]  What does [::-1] means?


Clicking on "Save Tag Edits" displays JSON response

Starting today, if I click on "edit tags", then on Save Tag Edits, the browser displays a JSON response rather than displaying the question.  Reproduced on Safari 12 and Firefox 63.  (A side complaint: I used to be able to hit Enter in the tag-editing field to save tag edits, but that hasn't worked for months.)


Does a card have a keyword if it has the same effect as said keyword?

I was looking at  and found the effect surprisingly similar to the keyword Surveil. To compare, first the wording of Contingency Plan and then the wording of the Surveil keyword:       Look at the top five cards of your library. Put any number of them into your graveyard and the rest back on top of your library in any order.     And       701.41a To "surveil N" means to look at the top N cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.     They quite clearly are the same, so can I assume the card states "Surveil 5" instead? And if so, does it trigger abilities which state "Whenever you surveil ..."?


I bought a laptop that came with a 128GB SSD and a 1TB HDD. Can I install ubuntu entirely on the HDD?

My laptop came with a 128GB SSD (C:) and a 1TB HDD (D:). It came with Windows 10 pretty much preinstalled, and I'm interested in downloading and installing ubuntu alongside it. The HDD only has a Steam library file on it (For installing any games from steam onto the HDD through the options menu on their install pop up when installing a game), and a Windows 10 upgrade file that appears to have nothing but two metadata files on it that I can't even open. Can I simply download ubuntu from the main site and then install it directly onto the HDD so I don't have to delete or partition the SSD, and if so, will it function? Also, assuming that the answer is yes to both previous questions, how do I go about doing this?


Proving that a function satisfying $|f(x)-f(y)| \leq |x-y|^3$ is constant

Let $\mathbb R$ be the set of real numbers and $f: \mathbb R \rightarrow \mathbb R$ be such that for all $x$ and $y$ in $\mathbb{R}$, $$|f(x)-f(y) |\leq |x-y|^3.$$ Prove that $f(x)$ is a constant.    This is a new type of problem for me and I feel I am missing some trick to simplify the given expression. Any help??


How can I calculate the equation $x^x=5$  Is it an exponential function?  Thank you.


I'm thinking of changing my username to my real name. Given that I have a presence on some of the sites here (mostly codegolf), what etiquette should I follow when choosing my new name?  As my username is currently Quincunx, I'm thinking of changing it to MyRealName (formerly Quincunx). Or perhaps MyRealName (né Quincunx). Maybe just MyRealName (Quincunx). If I do use these usernames, will people be able to recognize who I am? Or is there already a standard way to change usernames (such as relying on the profile picture)?


Several times I've heard sentences like You are not to be here. whereas I'd expected something with should. Or He is absolutely not to know..  What is this form? When should I use it?


Purchasing a house with parent-in-law's money, temporarily

Say I am about to purchase a £200,000 house (moving house, rather than first-time buyer), and can get a mortgage for the £120,000 difference I need. But, my parents-in-law have offered to loan us the £120,000 at 0% interest instead; and we would pay them back the same amount each month that we would have paid for the mortgage. The catch, however, is that at some point in the future they are likely to need the money back, although the timescales are not yet known - in which case we would have to take out a mortgage on the house at that point for the remaining value of the loan, in order to pay them back in a lump sum. What are the legal issues and risks with this approach - how should we make sure everyone is fairly covered? Is there any tax implications? Is there an easier way to approach this? Would we be less likely to get a mortgage in the future because the money would be being used to pay off this loan? Is there anything else I need to know before agreeing to this?


Only address or entire function is passed when we pass function as an argument?

I have been using JavaScript for quite sometime but this question keeps coming back to me every now and then. Consider the following code snippet :  function dummyFunc(inputFunc){     return inputFunc(); }  function getNumber{     return 100; }  dummyFunc(getNumber);   When am passing getNumber - only the address of function gets passed or entire function declaration gets passed to dummyFunc ?  If this is answered already please let me know ?


How to perform a "Select all" via keyboard, in recent versions of Gnome Terminal?

In (X)Ubuntu 14.04, I was able to perform a Select All operation via keyboard, in Gnome Terminal, invoking the menu (Alt-E -> A).  With more recent versions of (X)Ubuntu, I've noticed that the shortcuts for the menu bar are not available anymore.  For some operations, it's possible to set a direct shortcut (eg. Reset and clear terminal), but not for Select All.  Is there a way I can perform this operation via keyboard?  Note: I refer strictly to Gnome Terminal, not other terminal applications.


Close reason disappears when edited answer is reloaded

A little hard to reproduce, but here's what happens:   A question is closed which has an answer (might need to have only one answer) That answer is edited, [an edit has been made to this post, click to reload] appears Clicking that message makes the close reason disappear   Here's a video:   At first I though "Holy crap, that was reopened fast", then I reloaded the whole page and the close message was back. In fact, I think this bug has been around for quite some time.


Let $I=\langle 4, 2x,x^{2} \rangle$ in $\mathbb{Z[x]}$. Show that $I$ can not be generated by 2 elements.

I was trying like this: Let $I=\langle f(x),g(x) \rangle$. Then $4=f(x)q_{1}(x)+g(x)q_{2}(x)$. But $deg (4)=0$. So $deg(f(x))=0$ and $deg(g(x))=0$. So $f(x)=a$ and $g(x)=b$ where $a,b \in \mathbb{Z}$. Then I am stuck. Is this the correct way? Any help is appreciated.


Poisson random variable conditioned on sum

If $X_1,X_2...X_N$ are independent Poisson variables with parameters $\lambda_1,\lambda_2...\lambda_3$, then given $\sum_iX_i=N$, we have that   $X_i \sim \mathrm{Binom}(N,\frac{\lambda_i}{\sum_j\lambda_j})$ (straight from !)  I am looking for a proof of this -- I haven't really studied the relevant stats to know how to attack  this problem. Any help would be great. Cheers!


Minecraft: Didn't Save & Close and now won't open

My laptop battery died before I was able to save and close the game. Now when I start Minecraft, my game is not listed. I can see the folder of my game in Windows Explorer. How do I get Minecraft to open that game again?


Two electrons, or an electron and a proton, interact with each other because of the Coulomb potential, which can also be seen in the Schrödinger equation (which is the equation that describes the motion for elementary particles).  But how do an electron and a photon interact? Why can a photon kick up an electron to a higher atomic orbital, or why is a photon emitted when an electron jumps down to a lower orbital? A photon do not have any charge, so the interaction cannot be caused by the Coulomb potential. So what is it that causes the interaction, and how does that affect the Schrödinger equation? (Or well, the relativistic version of the Schrödinger equation, since we're dealing with photons.)


It's generally accepted that SSDs cannot be securely wiped by writing patterns to the drive, due to features such as wear leveling and over-provisioning, and that the most secure way to wipe a modern SSD is using the ATA Secure Erase firmware commands.   However, from my understanding this doesn't seem to apply to NVMe drives because they're not ATA-based - instead, they connect to and run via the PCIe bus. Looking at the  seems to confirm this, which has a secure erase option dedicated to NVMe drives:    This seems to confirm that NVMe drives have their own equivalent to the ATA Secure Erase command for SATA SSDs, but I haven't been able to find an NVMe equivalent for hdparm.   How exactly can I securely erase an NVMe SSD? I'm running Windows, but also have access to a Unix-like environment using Cygwin.


How can I set up a keyboard shortcut for switching input source?

I have to change my language option very often. It is hard when I write something with combination of both "English" & "Bangla", because I have to change that option rapidly.  Is there any way to set a keyboard shortcut, so that I can change my language option by it while typing?  I am using MacBook Pro with OS X.   Here is a screen shot:    Screen Shot of my Preference:


What is bound and unbound method in python

what is exactly bound method and unbound method in python. How does it differ when object is created?  i am beginner to python i wrote this small piece of code      class newclass:       def function1(self,var2):         self.var2=var2         print var2         self.fun_var=var2     newobject = newclass    newobject.function1(64)   I am getting error like this  Traceback (most recent call last):   File "basic_class.py", line 8, in <module>     newobject.function1(64) TypeError: unbound method function1() must be called with newclass instance as first argument (got int instance instead)   what is exactly bound method and unbound method in python


How can I derive Newton's gravitational law?  $$F=G\frac{m_1 m_2}{r^2}$$  Is it impossible to derive?  Did Newton get this just by obervations?


Visit visa for the UK. Currently unemployed but I have sufficient bank balance

I'm a Pakistani, currently unemployed. I want to visit my brother, who lives in England and can sponsor me. I have enough bank balance to support myself too.  I'm single and unemployed. Is it possible for me to get a visa? The recent job I had was for a year and I was let go in May 2018. I'm a dentist by profession. Before applying for a new job I want to travel a bit. So is there any chance of getting a visa?


Consider the function $f:\mathbb R\to \mathbb R$ and $g:\mathbb R\to \mathbb R^+$ (in that question $\mathbb R^+$ is a set of nonnegative real numbers). And let define for any $x$ in domains of this functions $f(x)=x^2$ and $g(x)=x^2$. And if we look at set-theoretical definition of function it seems this functions must be equal, because $f$ contains all elements of $g$ and vice versa. But $f$ is not surjective but $g$ is. Isn't it a contradiction ? Or maybe I made a mistake and this functions are not equal, so are this functions equal ?


What book features people living in a tree who move up it in a bubble?

I really hope someone can help me. There is a book I read years ago and cannot remember the name of it but would love to read it again.   If I remember correctly it was about people living in a tree and they would get into a bubble or something like that to move up the tree. People thought they were dying but it turns out they were moving up a level in life.   Apparently the same author wrote a story about someone digging up an old teacup handle that is about 3 meters long but it turns out the human race was modified and are now tiny.  Hope I haven't made all this up because they sound like crazy ramblings.  :-D