I am working on a new site collection inside office 365. now when i select to create a new private site collection , i got this dialog:-    where it mentioned that the "Template Selection" will be "2013 experience version will be used".. now as for July 2017, can i have the 2016 experience inside my office site collection? or as for July 2017 the only experience we have is 2013 for our office 365 site collections?

We are using, i think, SharePoint Online as a part of Office 365. Perhaps I have the terminology correct, it is confusing.  When I go to the SharePoint Admin Center and lick on site collections I noticed that all of our site collections are Version 2013.  When I go to create a new site collection the window says: "2013 experience version will be used".  Is 2013 the newest version? I have read about 2016. Can you create a site collection using a 2016 experience? It seems as though even though we user SharePoint through Office 365 there are still versions that match up with the on-prem versions?  My questions:  1) Can I create a site collection using 2016  2) What do the versions mean, and will there always be a version even though we are using SharePoint through Office 365.


Is there a good substitute for one of the "in terms of"s in the following sentence?     Income taxes have costs in terms of the welfare loss of people who pay taxes and also benefits in terms of tax revenue.   Can I use "as" instead of the second "in terms of"?     Income taxes have costs in terms of the welfare loss of people who pay taxes and also benefits as tax revenue.

I have came across this reference:      This phrase is virtually meaningless, but we often hear it on the news and in bloated speeches. “In terms of” is really just a wordy and sloppy transition—usually an unoriginal disguise for a simple preposition, such as “in,” or a more elegant phrasing, such as “in relation to.” “In terms of the cost, it is high,” is easily revised to “Its cost is high.” Do not use “in terms of,” or do so trembling.   Is the reference really right?  Can I use the following sentence?     The figures are expressed in terms of a percentage/in percentage terms.    If so, the phrase "in terms of" seems not to be referred to relation.


My friend and I are making iOS apps and we have are not graphic designers. We have no idea how to do any of that stuff.   Where can we find a graphic designer and how much would he/she cost?

I am developing the backend for a website. I always had the trouble of making an attractive design for my websites and have never hired any graphic designer yet. I have no logo nor web template.  What are the steps to hire a graphic designer? What information should I read about before hiring one in order to make most out of our time? Where should I find him? What questions should I ask him? How much do they charge and what qualifications should I look out for? Should I disclose my business ideas to the designer or could that be risky?


I want to connect headphones to my iPhone (7), and then play all audio from my MacBook (Pro with Retina, 15" Mid-2015), through the headphones connected to my iPhone.  macOS Mojave 10.14.6, iOS 12.4.1  How can I do that?

Say I am playing a video on my MacBook Pro, and I don't want to distract others with the sound. The problem is, I don't have a 3.5 mm Headphone or AirPods at my hand, but I have an iPhone 8 Plus and its EarPods with Lightning Connector. Can I play the sound from the video playing on macOS with the iPhone, preferably without connecting the iPhone to the Mac so that I can plug in the EarPods to the iPhone's socket?  This is basically the reverse of


Here is my code public class xmlreq extends TestBase  { @Test public void buildRequest() {     logger.info("starting");     RestAssured.baseURI="http://webservices.oorsprong.org/websamples.countryinfo";          httpRequest=    RestAssured.given();     String b= "<soapenv:Envelope xmlns:soapenv=\"http://schemas.xmlsoap.org/soap/envelope/\" xmlns:web=\"http://www.oorsprong.org/websamples.countryinfo\">\r\n" +              "   <soapenv:Header/>\r\n" +              "   <soapenv:Body>\r\n" +              "      <web:CapitalCity>\r\n" +              "         <web:sCountryISOCode>IND</web:sCountryISOCode>\r\n" +              "      </web:CapitalCity>\r\n" +              "   </soapenv:Body>\r\n" +              "</soapenv:Envelope>";     httpRequest.header("Content-Type","text/xml");     httpRequest.body(b);                    response=   httpRequest.request(Method.POST, "/CountryInfoService.wso?wsdl");          Assert.assertTrue(response.getBody().asString()!=null);     System.out.println(response.getBody().asString());      }  @Test(enabled=true) public void validate() {     String a = response.getBody().asString();     Assert.assertTrue(a.contains("New Delhi"));      }  }

Is there a possibility of using REST Assured library for testing SOAP webservices? I have a bunch of Test Suites in SOAP UI and I need to check if there is possibility of using REST Assured. Can anyone suggest if this is possible? Many thanks for any comments.


Theorem: the characteristic of a non unital integral domain must be $0$ or a prime.   Assume that $mn$ is the characteristic of a the integral domain for every $a$ in the integral domain we have $(mn)a^2=(ma)(na)=0$ then $ma$ or $na$ must be zero.  So for every $a$ in the integral domain $na$ OR $ma$ is zero but I can't say one of $m$ and $n$ works for every $a$ !

By an integral domain, we mean here, a ring (not necessarily with unity) in which $ab=0$ implies $a=0$ or $b=0$.   Question: If an integral domain without unity has positive characteristic, is it necessarily prime?    An integral domain $D$ is said to be of finite characteristic if there exists a positive integer $m$ such that $ma=0$ for all $a\in D$. [cf. Topics in Algebra- I. N. Herstein, 2nd Ed., p. 129]  My question is a slight modification of Problem 6 in [Topics in Algebra- I. N. Herstein, 2nd Ed., p. 130]


"An error occurred.Please run the Package Manger form the right-click menu or apt-get in a terminal to see what is wrong.The error message was:'Error:BrokenCount>0'.This usually means that your installed packages have unmet dependencies." the software center is showing virtualBox 5.1 and saying: " fail to satisfy all dependencies ( broken cache), i red the posts relevant to this error but didn't help.

I have the message:   Error Broken count >0 Check if you are using third party repositories. If so disable them, since they are a common source of problems. Furthermore run the following command in a Terminal: apt-get install -f Details: The following packages have unmet dependencies: firefox-globalmenu: Depends: firefox (= 19.0+build1-0ubuntu0.12.04.2) but 19.0+build1-0ubuntu0.12.04.1 is installed   Any suggestions?


I have created two or three bootable CD's from downloads, one with Ubuntu 15.1 and one from mini.iso.  I either get a message that there is some problem with PAE which I have no idea how to deal with, or I get a BOOT: prompt after an ISOLINUX message statement mentioning Peter Alvin.  I have absolutely NO IDEA what I am supposed to do with this.  The bootable CD doesn't just start installing Ubuntu like I hoped it would.  What do I do with the BOOT: prompt?  or the PAE message?

After burning Ubuntu 12.04 to a CD, I tried booting and got the message:  This kernel requires the following features not present on the CPU: pae  Unable to boot - please use a kernel appropriate for your CPU.   What does this mean?


Is it possible to prove that $\text{tr}(AB)=\text{tr}(BA)$ without using matrices or having to choose a particular base ?  Such a proof should probably use a non matricial definition of traces. One could say for example that $\text{tr}(A)$ is the linear coefficient of the characteristic polynomial $\det(A-X\text{Id})$. In case the latter doesn't satisfy everyone, here is a definition of trace suggested in Halmos's Finite Dimensional Vector Spaces. Let $E$ be a $n$-dimensional vector space over some field $k$. We recall that the space $W$ of alternating $n$-linear forms $\omega: E^{n}\rightarrow k$ is one dimensional over $k$. Given an endomorphism $f$ of $E$ we can define the linear application \begin{align*} \bar{f}:\quad W &\rightarrow W \\ \omega(x_{1},x_{2},...) &\mapsto  \sum_{i} \omega(x_{1},...,x_{i-1},f(x_{i}),x_{i+1},..) \end{align*} Since $W$ is one dimensional $\bar{f}=\lambda Id$. We set $\text{tr}(f)=\lambda$.  The analog definition of the determinant easily yields $\det(AB)=\det(A)\det(B)=\det(BA)$, but this no longer works here. One could fix a base $e_{1},e_{2},..,e_{n}$  and do the calculations but this would kind of beat the point, since it is essentially the same as computing with matrices.

I am searching for a short coordinate-free  proof of $\operatorname{Tr}(AB)=\operatorname{Tr}(BA)$ for linear operators  $A$, $B$ between finite dimensional vector spaces of the same dimension.    The usual proof is to represent the operators as matrices and then use matrix multiplication. I want a coordinate-free proof. That is, one that does not  make reference to an explicit matrix representation of the operator. I define trace as the sum of the eigenvalues of an operator.  Ideally, the proof the should be shorter and require fewer preliminary lemmas than the one given in .  I would be especially interested in a proof that generalizes to the trace class of operators on a Hilbert space.


I'm having a problem in both Java and MATLAB where two numbers which should be the same apparently aren't.  Java:  float f1 = 0.3f-0.2f; float f2 = 0.4f-0.3f; System.out.println(f1==f2); // Prints false  System.out.println(f1); // Prints 0.10000001 System.out.println(f2); // Prints 0.099999994   Obviously f1 should be equal to f2. What is the most efficient (computationally) method to replace equals below that would return true?  public boolean equals(float f1, float f2){     return f1 == f2; }   I will need to operate on hundreds of thousands of floats so optimization is important here.

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


My friend suggest me Ubuntu OS instead of windows 7 because on ubunut no virus,trojan,rootkit this is true ?  Thanks, Michi

At  there is this "only in ubuntu" that says "Built in virus protection":  What is the Ubuntu built it protection? What is the program in charge of this and how does it work?


Need fast solution how to show series expansion of function at x=0:  $$f(x)=\frac{3x}{1+x^2+x^4}$$  Please some hints.


I have a question just opposite to : my less exits without clearing the screen, but I have never used -X.  The options I use is as follows:  $ echo $LESS  -N -g -i -M -R -w -z-4 $ echo $LESSOPEN $ $ echo $TERM ansi   I remember when my less started to change its behavior: when I was trying to type something to another application but my cursor was in the terminal with less opening. When I realized I'm typing into a wrong place and tried to quit less, the file contents start to remaining to my terminal. I'm using MacOS terminal (not iTerm2).  As @roaima suggested, my issue is to get the less's standard behavior without -X. However, -+X does not work; and -X is not in LESS.  I'm using OSX Terminal.app, not iTerm2.

Neither less or less -X clear screen on exit. At the same time, vim does....  Env iTerm2, protocol mosh, server Centos + tmux + zsh  iTerm2: report term as xterm-256color  tmux: set -g terminal-overrides 'xterm*:smcup@:rmcup@', no change to alternate-screen  $TERM is final set to screen-256color  I also tried     tput smcup | od -c and     tput rmcup | od -c  suggested . It outputs correct answer.


I would like an 'enlarge' option for text blocks that are wider than the window, such as an enlarge link below wider blocks, or something similar.   I did find  about resizable text blocks, which would be fine, too, but the answers don't seem to fit how I see SE working in my browsers. The answer from Cody Gray I can't repeat on any of my browsers (I can't resize any of the blocks, can you?). Reformatting an entire log snippet to fit the window is tedious and I find harder to read than having everything on one line.  I did observe that the site is slightly wider on my 2560 wide monitor than on my 800 wide tablet, but only by about 6 characters.  In the Android app, I can click on a text block and have it move to the foreground and be as wide as the screen. I would like to have this functionality in the desktop version of the site, as well.

Is there a way for a reader (not the OP) to expand a scrollable window containing source code in a question?  I sometimes have difficulty understanding a block of code because I can't see it all at once. I find myself having to continually scroll the code up and down within the window.  It would be nice to be able to request that the code in all of its entirety be displayed in the question.


I installed Ubuntu 14.04.1 on Dell 7537. My laptop has nvidia 750M graphic card. The problem is that OS the freezes sometimes without any reason.  I installed nvidia-current but nothing changes, the OS freezes and touchpad/keyboard don't work, the only thing I can do is power off the PC.  How can I solve? Where can I find some logs?

I am fairly new to Ubuntu and I was wonder what a good way is to debug when something crashes?   For example: I installed 11.04 and the default media player banshee makes my laptop crash after a few minutes of playing music. Since the system completely freezes and there is not error message it's hard to find out what is wrong.  Second problem I have is that sometimes the system crashes to login. I am suspecting it to be a Chromium or Flash but I am not 100% sure.  So anybody got some tips on how to debug stuff like this?


Here is my system specifications  Processor: Intel Core i7-8700 Processor GPU: Intel® UHD Graphics 630 OS: Debian 9.6 (Stretch) Monitor resolution: 1920 x 1084   Even though I have a full HD monitor, I can't set a resolution higher than 1024x768.  The display is labelled as "Unknown Display".  xrandr shows a warning "xrandr: Failed to get size of gamma for output default"  GPU usage is always 0% (Checked using intel-gpu-tools)  Experiencing screen tearing.  When searching online, most of the solution says to enable Jessie backports. Since I am already on stretch, I think I don't have to do it. How am I supposed to solve it, then? does intel provides any drivers?    Edit  For those who has the same issue, try  answer as suggested by @Stephen Kitt. It worked for me.

I just installed Debian 9 on my laptop, however Wifi isn't working and I'm not sure if my graphic card is either. I'm sure that it's just a lack of drivers, but I've never actually had to update drivers on Linux before. So how do I do that?


After you get the longest road card, can you start building on it and still retain the longest road card?

Imagine the following setup. There are 3 (or more) players with an equally long road. What would happen if the longest road was broken? How is it decided who obtains the longest road from there on?


I'm going crazy trying to figure out how to correctly iterate a large (>100 MB) XML file using PHP. I know how to process other XML files; as long as there are no <ns2:*> items it works great, but this file seems impossible. Please help me out. Example of the XML file: <result version="3.0" xmlns="xml:output" xmlns:ns2="xml:common">     <products>         <product groupingId="347849" language="en">             <ns2:name>Example Name</ns2:name>             <ns2:description>Example description.</ns2:description>         </product>     </products> </result>  I process other XML files this way (this does not work when I load the file structured like the example above).             $xml = new XMLReader();             $xml->open($file);                                          while ($xml->read() && $xml->name != 'product') { ; }             $i = 0;             while ($xml->name == 'product') {                 $xmlProduct = new SimpleXMLElement($xml->readOuterXML());                 echo $xmlProduct->name;             }  Everyone's happy. But that's not the case now. (I need the XMLReader + SimpleXMLElement combo in order to stream large XML files.) If you know how to fix this, please let me know. Thanks. Solution: $values = $xmlProduct->children('ns2', TRUE);

I have this as xml:  <root xmlns:event="http://www.webex.com/schemas/2002/06/service/event">     <event:event>         <event:sessionKey></event:sessionKey>         <event:sessionName>Learn QB in Minutes</event:sessionName>         <event:sessionType>9</event:sessionType>         <event:hostWebExID></event:hostWebExID>         <event:startDate>02/12/2009</event:startDate>         <event:endDate>02/12/2009</event:endDate>         <event:timeZoneID>11</event:timeZoneID>         <event:duration>30</event:duration>         <event:description></event:description>         <event:status>NOT_INPROGRESS</event:status>         <event:panelists></event:panelists>         <event:listStatus>PUBLIC</event:listStatus>     </event:event>     ... </root>   How can I loop through all of the event:event nodes and display, for example, all of the event:SessionKey's?   This does not work:  $xml = new SimpleXMLElement($r); $xml->registerXPathNamespace('e', 'http://www.webex.com/schemas/2002/06/service/event');  foreach($xml->xpath('//e:event') as $event) {  var_export($event->xpath('//e:sessionKey')); }


My parents and I are travelling to Europe in May. Below is our itinerary. Will we require a single- or a multiple-entry visa? We have Indian passports.  My itinerary:   Italy: 7th to 15th May Czech: 15th to 19th May Belgium: 19th to 22nd May Netherlands: 22nd to 26th May   Parents: Italy: 7th to 15th May  Since I am visiting multiple countries, would I require a single-entry visa or a multiple-entry visa? From what I understand, we would require a single-entry, since I am not exiting the Schengen area during my trip.

I applied for schengen visa via Norway embassy. I got a single entry visa (even though I asked for multiple entry). Now my plan actually is to land in France (Paris), travel through Belgium to Amsterdam by road and then fly from Amsterdam to Bergen in Norway. I am curious to know whether flying from Amsterdam would be considered as exiting the Schengen state even though I am flying to another Schengen state?   I know it is OK to travel from one Schengen member country to another within the visa tenure and without exiting the Schengen states. I did it before last year by entrying into Austria and traveled through Czech Republic, Germany and then reaching Switzerland (all by road) and then flew back to Dubai where I reside.  But I am really unsure of air travel that how is it taken when you fly from one Schengen state to another?


If you select 20 people at random. What is the probability that at least one pair of people share the same birthday? (Ignore leap years.)  I was thinking of the total number of possibilities so like (20)^20, for the denominator of the fraction. But I am not sure about this. Also am not too sure about how to do the numerator i.e. the choosing using factorials?

$n$ people attend the same meeting, what is the chance that two people share the same birthday? Given the first $b$ birthdays, the probability the next person doesn't share a birthday with any that went before is $(365-b)/365$. The probability that none share the same birthday is the following: $\Pi_{0}^{n-1}\frac{365-b}{365}$. How many people would have to attend a meeting so that there is at least a $50$% chance that two people share a birthday?   So I set $\Pi_{0}^{n-1}\frac{365-b}{365}=.5$ and from there I manipulated some algebra to get $\frac{364!}{(364-n)!365^{n}}=.5\iff (364-n)!365^{n}=364!/.5=.....$   There has to be an easier way of simplifying this.


Implement a method for adding elements to the class CacheMemory. The Class cache memory has an array memory whose length is passed through a constructor.Elements can be added to the array only if it has not been added before and if the length of the arrays added is within the boundaries of the array.(within its length).  This is the code I came up with so far:  public class CacheMemory {      private String[] memory;      public CacheMemory(int length) {         this.memory = new String[length];     }      public void addingElementsToCache(String mem) {         for (int i = 0; i < memory.length; i++) {             if (memory[i] != mem) {                 memory[i] = mem;                 System.out.println(mem);                 break;             } else {                 System.out.println("Element already exists");             }         }     } }   If i call this method without break,of course it will print out the string five times,but I don't want the same string to be printed out five times,I want to add five different strings and then,while loop goes through the array,and comes to element that has already been passed,to print out the message.

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


I have Mac OS PC, let's name it PC1, and I have Linux PC (PC2), on Mac os PC I have python script(reverse shell), I need to make it run on system start or user login(no matter) threw terminal, I have sudo access to Mac OS terminal from my Linux, so how can I do it?

There is a directory in System/Library for startup items I presume: StartupItems  I need to have a shell script that will configure ethernet interface at start up, with local network address and subnet mask. I need to do this because the network preferences for configuring the ethernet interface will NOT set it using manual settings. THIS appears to be a serious bug, or my installation is bad.  I was given the advice to use  networksetup from the command line but that will not configure the ethernet interface in such a way that the configurations will be there on reboot.  The script needs to do its work with root privileges, or with sudo, but I am assuming that if it uses sudo, there will be a password dialog presented at boot time when the boot process gets to that script.  (I have had enough experience with FreeBsd and Linux to find my way around in the terminal, but not necessarily as it applies to Mac OSX)


How do I generate equally spaced points on the circumference of a circular feature in ArcMap?   I am currently working on a project where I need 36 equally spaced UTM coordinates that form a silo.

I actually did this a few weeks ago but I can't remember how.  I want to create points on the perimeter of a set of polygons at a specific distance interval. I am using ArcMap.  I could do Polygon Vertices to Points, but that would only give me points on the vertices, which I don't necessarily want. What I want is a regular set of points on the perimeter of the polygons.  This is my base polygons:    And this is what I would like to get (the points at regular intervals):    Any ideas?


, the magical skill of extracting feelings and memories from another person's mind.  Both men interacted almost daily with the fake Mad-Eye Moody, Barty Crouch Jr., for an entire school year. Yet neither man suspected Crouch for who he was until the end of the school year.                                  How did Barty Crouch Jr. evade detection by two skilled Legilimens?  A stray thought by Crouch could have given away his identity or his plans. Was he trained in Occlumency to keep his thoughts private from prying minds?  Please provide answers based on canon sources.

An Occlumens is a practitioner of Occlumency, while Occlumency means closing the mind. Despite being in the same school with two great Legilimens (Dumbledore and Snape), he was only discovered to be an impostor after the last round of the Triwizard Tournament in Goblet of Fire:  “Moody,” Harry said. He was still in a state of complete disbelief. “How can it have been Moody?” “This is not Alastor Moody,” said Dumbledore quietly. “You have never known Alastor Moody. The real Moody would not have removed you from my sight after what happened tonight. The moment he took you, I knew — and I followed.”  Does this mean that Barty Crouch Jr. is an Occlumens? Because if not, then Snape or Dumbledore would have found it out earlier, right?


nohub  and & seem to have a similar effect on the surface, they both start processes without occupying the shell from which they have been started, how do they differ on a deeper level?

What are the differences between  $ nohup foo   and  $ foo &   and  $ foo &  $ disown


We have a network of around 100 clients running RHEL and one machine hosting a mirror of RedHat's official repository (via rsync).  The clients point to the server to get their updates (via .repo file), but currently I have to manually go into each one and execute   $yum check-update $yum list updates $yum clean all $yum update  The idea is to have the server do a sort of "push updates" and all the clients receive and apply the corresponding updates on their own.

Coming from Windows administration, I want to dig deeper in Linux (Debian). One of my burning questions I could not answer searching the web (didn't find it) is: how can I achieve the so called "one-to-many" remoting like in PowerShell for Windows?  To break it down to the basics I would say:  My view on Linux:    I can ssh into a server and type my command  I get the result. For an environment of 10 servers I would have to write a (perl/python?) script sending the command for each of them?   My experience from Windows:    I type my command and with "invoke-command" I can "send" this to a bunch of servers (maybe from a textfile) to execute simultaneously and get the result back (as an object for further work). I can even establish multiple sessions, the connection is held in the background, and selectively send commands to these sessions, and remote in and out like I need.   (I heard of chef, puppet, etc. Is this something like that?)    Update 2019: After trying a lot - I suggest Rex (see ) - easy setup (effectively it just needs ssh, nothing else) and use (if you know just a little bit perl it's even better, but it's optional) With  you can do adhoc command and advance it to a real configuration management (...meaning: it is a CM in first place, but nice for adhoc tasks, too) The website seams outdated, but currently (as of 01/2019) it's in active development and the IRC-Channel is also active.  With Windows' new  there are even more possibilities  you can try: rex -u user -p password -H 192.168.1.3 -e 'say run "hostname"'


I try to use KDE desktop a couple days, I think I like it and I don't wanna go back with GNOME. What will I do to remove it completely? I am using Ubuntu 20.04 by the way Thanks

I have just installed the final version of Ubuntu 20.04 LTS desktop system from ubuntu-20.04-desktop-amd64.iso. After two days of testing I completely do not like its graphical interface - the GNOME Shell. Even installation of GNOME Flashback does not help either.  So I want to completely remove the GNOME Shell with all its trails from my system without re-installation. Just want to start from scratch like it was approximately if I have installed Ubuntu from .


How can I prove this?  Let $f_n \to f$ in $L^2$ and $g_n \to g$ in $L^2$. Then $f_n \cdot g_n \to f \cdot g$ in $L^1$.

Let $\mathrm{X, (X_n)_{n\in\mathbb{N}}, Y, (Y_n)_{n\in\mathbb{N}}}$ $\in$ $\mathcal{L^2}$ be random variables. Prove that  ($\mathrm{X_n}$ converge to $\mathrm{X}$ in $\mathcal{L^2}$ and $\mathrm{Y_n}$ converge to $\mathrm{Y}$ in $\mathcal{L^2}$) $\Rightarrow$ $\mathrm{X_nY_n}$ converge to $\mathrm{XY}$ in $\mathcal{L^1}$.  My attempts: I think Jensen's inequality is needed here, with the function $\phi$($\mathcal{x}$)=$\vert$$\mathcal{x}$$\vert$, because the assumption is similar to a property stated here , but I am unable to clearly formulate a strategy to solve this problem


I read somewhere that the addition of R2 provides the DC return to ground however this would reduce the overall input impedance of the op-amp. Input impedance must be high for an op-amp. How to solve this problem?

In the case of a non-inverting amplifier, if I DC couple the input signal with a capacitor only, \$C_1\$ (i.e. no resistor to ground), sources (as well as an experiment in the lab) show me that the op amp input will be saturated as the input bias current deposits charges on the terminal without having a return path to ground. This is solved by using connecting a resistor (\$R_1\$, as shown in the image below) to ground to create the return path. [The image is reproduced from an answer by "Neil_UK" on one of my previous questions, thanks Neil!]    My questions:   1) How is the input bias current able to continuously deposit charges and saturate the input if I don't use the resistor? The resistor should not allow the DC bias current through, so where is this current flowing from/into?  2) Why is this not a problem for the feedback path to the "-" terminal? There is no resistor to ground in that case, and capacitor \$C_2\$ seems to be causing no issues. The PDFs I've been reading suggest that the feedback behaves similar to when I have a resistor to ground by acting as the return path, how is this?


I am using lightning:input for autocomplete (ui:inputText doesn't really work here correctly as it doesn't update value until you remove focus from field):                  <lightning:input                       label=" "                       placeholder="Opportunity or Project"                       name="myname"                       onchange="{!c.searchOpportunities}"                       value="{!v.newRecord.opportunity}"/>   However, I do not like the whitespace left above the field. What is the right way to remove it? It's kind of annoying that its required in first place, esp. when we have alternatives like placeholder (I know I know, semantically it's not the same, but in some cases it makes sense to use placeholder).

I would like to use the lightning:input component in a data table. Therefore my question is: Is it possible to remove the label attribute on the lightning component?  <lightning:input type="number" label=" " name="aNumberInputField" />   is quite not the solution for this (shifted... doesn't look good), and removing the attribute throws an error. Any advise?


How can I express in an informal way that I've eaten, and ready to continue what I was doing before, akin to saying that my phone's charged up, or a petrol tank has been filled up?  For example:     User A: Are you ready?      User B [who's just had lunch]: Yep, I'm ready. I'm [fed up] and ready to continue.

English is not my native language, but when I was studying in the US, I was always trying to find an alternative to      I'm full!   I felt that it was a very improper way to express that I have eaten enough, especially when I was invited for dinner. I remember having difficulties demonstrating my gratitude towards my hosts when using this expression.  Being full feels to me a bit like a car that has been filled with gasoline and gasoline is just used to continue working. That's not what I want to say...   Is there a better word I can use? I haven't found one in the dictionary. There are, of course, long forms:     I have had enough [, thank you].   that I have learned to use, but I wonder if there is a short one. Other Languages have rassasié (French), sazio (Italian) and satt (German). Should I use satiated?    Update: Thank you all for the overwhelming response! After 13 answers, I feel I got a better understanding of the phrase. I'm grateful for @Andrews answer, because he took the cultural aspect into consideration. This was the decisive part that I missed. I can also understand @MT_ Head that saying No thank you, I'm full while smiling isn't offensive at all. Thanks for that.   I conclude that there is not a single wide spread word I can use which doesn't sound stilted or strange (or even has a touch of sexual pleasure).   I now have a repertoire of polite responses available. I'm accepting the most helpful answer for me, but most of you got my up-vote. :)


The question is: If $a_1,a_2,...a_n$ are the sides of a convex polygon $A_1A_2...A_n$  then prove the inequality: $$\frac{a_1^2+a_2^2+...+a_{n-1}^2}{a_n^2}\ge\frac{1}{n-1}$$ How do I even start approaching this? The only idea I tried was using Cauchy-Schwarz but I couldn't make the RHS appear. Can someone please provide a hint or some alternate method? Any help would be appreciated.


I have a directory that I want to find sizes on. When I run the two following commands, I get very different results. I expect the second to produce results like the first. Any ideas why?  $ for d in `echo *`; do du -sm $d; done 5649    archive 2055    archive.git 426     filtered 65      filtered.git 14      filtered.git.bfg-report $ du -sm * 5649    archive 1       archive.git 426     filtered 1       filtered.git 14      filtered.git.bfg-report

I'm trying to move some data over and to start with I'd like to make sure that the size is ok. I run into a problem however, if I check the folder with   du -sh  myfolder/ 780M    myfolder/   but   du -sh * .. 71M     myfolder ..   I thought it might be something to do with hidden files but this particular folder does not have any inside.  Am I missing something?


I need to prove that $$(1+2+{...}+k)^2 = 1^3 + {...} + k^3$$ using induction. So the base case holds for $0$ because $0 = 0$ (and also for $1$: $1^2 = 1^3 = 1$) I can't prove it for $k+1$ no matter what I try! Can you give me a hint?

How can I prove that     $$1^3+ 2^3 + \cdots + n^3 = \left(\frac{n(n+1)}{2}\right)^2$$    for all $n \in \mathbb{N}$? I am looking for a proof using mathematical induction.  Thanks


I am trying to create a custom array and want to add data by indexing using k (int). I don't know why it's giving me a null pointer exception.  public class FourElements_Sum_GivenVal {      int sum,first,second;      public static void findFourElements(int arr[],int n,int x) {          int size=((n)*(n-1));         FourElements_Sum_GivenVal aux[] =new FourElements_Sum_GivenVal[size/2];         int k=0;         //System.out.println((n*n-1)/2);          for(int i=0;i<n-1;i++) {             for(int j=i+1;j<n;j++) {                 aux[k].sum=arr[i]+arr[j];                 aux[k].first=i;                 aux[k].second=j;                 k++;              }         }         public static void main(String[] args) {         // TODO Auto-generated method stub            int arr[]= {1,2,3};           int x=23;           findFourElements(arr,arr.length,x);     }    }

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


I have tried the following:  public class OuterClass {     abstract class abstract AbstractInnerClass     {         final Object member;         public Abstract InnerClass(Object member) { this.member = member; }     }     public class InnerClass extends AbstractInnerClass { } }   However, this gives me a compile fail:     Parent class has no 0-argument constructor for implicit construction   However I can change InnerClass to:  public InnerClass extends AbstractInnerClass {     public InnerClass(Object member) { super(member); } }   Another change I can make indicates at least some constructors inherit:  public class AbstractInnerClass {     Object member;     public AbstractInnerClass() { }     public AbstractInnerClass(Object member) { this.member = member; } }   Thing is, I do not care about the 0-argument constructor and don't foresee ever having any use for it. I tried to make an abstract constructor:  public class AbstractInnerClass {     Object member;     public abstract AbstractInnerClass(Object member) { this.member = member; } }   Unfortunately the above also results in a compile fail:     Constructors cannot be abstract   Is there no way to inherit constructors?

If I have an abstract parent class like this:  abstract class Vehicle {     public Vehicle(Person driver) {         //     } }   and then I create a child class like this:  public class MagicCarpet extends Vehicle {     //this won't compile }   I encounter the following Compile Error:     Error: Parent class has no 0-argument constructor for implicit construction at line ... column ...   Obviously I can explicitly re-declare a constructor on the child class toget it to compile:  public class MagicCarpet extends Vehicle {     public MagicCarpet(Person driver) {         super(driver);     } }   But I feel this isn't DRY. Not sure what's actually going on under the covers here.  How can I get a constructor (other than the implicit 0-argument one) to be inherited by a child class?


I followed the steps mentioned in: , to change Keyboard shortcuts to switch to another workspace, as can be seen in the following picture:    Most of the times this works. But, sometimes this shortcut that I have set Super+1 and so on conflicts with the other shortcut: The icons on the dash or Ubuntu Dock (on the left edge of the screen gets switched) as shown in the following figure: (You can observe that numbers appear at the bottom of each icon.)    How can I completely disable or change the shortcuts to switch apps on the vertical dash, so that it doesn't conflicts with my workspace switching shortcuts?

I like to switch workspaces via Super+Number. But unfortunately the default behavior in Ubuntu for Super+Number is to select applications from the dock.   Is it possible to disable that functionality? I've tried overriding the keyboard shortcuts but it doesn't appear to be working.


I have the following table structure:  tags            image_tags          image ------------    ----------------    --------------- id  tag         tag_id  image_id    id    etc... ------------    ----------------    --------------- 1   apple       1       1           1   image_1.jpg 2   banana      2       1           2   image_2.jpg 3   cherry      2       2                 3       2   Tags are joined to images through a many-to-many relationship.  I want to get a list of tags that appear together in at least one image.  Something like:  ----------------- a        b ----------------- apple    banana banana   cherry  etc..   Each tag pair should only appear once, and the order of the pair doesn't matter.  We'll be using this data to create a .dot file for a network graph.  I'm not sure exactly how to structure a query like this.

Basically the question is how to get from this:   foo_id   foo_name 1        A 1        B 2        C   to this:   foo_id   foo_name 1        A B 2        C


a vacuum airship is a hypothetical airship that is evacuated instead of using a lighter gas. Really, once I first saw this, I thought, "Why did I never think about this before?!" Indeed, whenever I pictured an evacuated container, I thought it would just sit there.  But no. Instead here on Earth, a theoretical vacuum airship could lift 1.28 grams per liter of evacuated space, a 14% boost over helium, owing to the density of air.  Of course, the air is also the destroyer of this powerful capability; it exerts 14 psi, or ~0.1 MPa!! According to Wikipedia's calculations, a hemispherical shell would have to withstand $$450,000 kg^{-1} m^5 s^{-2}$$ which is over 3 times the buckling pressure of diamond.  Give up? Not yet. There is a couple of interesting ideas I thought about:   Why hemispherical? Wouldn't other shapes do well also? For example, a sphere, or a cylinder (maybe a cylinder with radius=height). From what I know (not much..) about spherical items, I suppose it would distribute the pressure evenly. Wouldn't that mean that diamond could easily sustain 100 kPa (withstands up to 600 GPa)? Is there no other way around this obstacle? Could we make use of any exotic forces or structural methods? (One interesting suggestion: Gradually evacuate the helium-filled airship, slowly going up, so that when we reach a total vacuum the airship is basically in space? In that case there wouldn't be any powerful pressure from air...)

Is it possible to make a solid rigid evacuated "balloon" out of Beryllium or other elements or alloys?  The critical buckling pressure at which an evacuated sphere is given as $$ P_1=\frac{2E\cdot\left(h/R\right)^2}{\sqrt{3\left(1-\nu^2\right)}} $$ where $E$ is , $h$ the shell's thickness, $R$ the radius to the midsurface shell, and $\nu$ is .  Of course this is theoretical and experimental and literature values for submersibles hover around 1/4 of the theoretical pressure.  Beryllium has the following properties:   Density=1.85 g/cm$^3$ Young's Modulus=287*10$^9$ Pa Poisson Ratio=0.032   Calculating the upward force, buoyancy at 101.3 kPa atmospheric pressure and Radius of 10m gives 4.24*10$^8$ N. The weight of this sphere with shell thickness 1mm has 2.32*10$^7$ N downward force of Beryllium material, so it will theoretically float at ground level.   Calculating the critical buckling stress of this beryllium sphere is 331.57 kPa, which is 3.27 times the atmospheric pressure of 101.3 kPa, so theoretically it won't buckle. But in experimentation done in earlier experiments as stated before, due to construction/material non-ideal situations, the critical buckling formula predicts about 4 times stronger than actual, so it would need about 400 kPa, not 331 kPa as Beryllium sphere with this specification would hold. Increasing the strength capability also increases weight and therefore lowers it's ability to float, but Beryllium is the closest element with this situation I have calculated that could work if ideal (I have only been using periodic table elements and household materials)  Is it possible with an alloy of elements? Using the equations for buckling and buoyancy, the following is needed. What alloys/materials come to your mind?  Material considerations:   Material with larger Poisson ratio Material with larger Young's Modulus Less dense material Construction (is it possible)   Material considerations affect on lift   Thickness can be larger, increases strength by the squared. But also increases weight. If a material with lower density with similar structural properties as Beryllium is used, it would help. Radius can be lower for same reason, but also lowers buoyancy (volume)   My other designs (don't worry about these just yet, just if you are curious is a vacuum sphere with a pressurized "outer tube" with spokes in tension (carbon fiber nanotubes maybe) to keep the 2 spheres in position. Another is a spherical truss out of carbon fiber nanotubes with a light membrane around. The truss prevents the outer membrane from collapsing due to the atmospheric pressure  The "point" of this if you ask, as to why not use a traditional balloon is it can be used as a boat by filling the sphere with air, and then used as a aircraft at will by evacuating the sphere. An alternative mode of transportation for sea vessels etc.


I installed tails on a USB and everything was great but when I tried to browse the web, I get it is anonymous but it makes it slower than normal to load websites or videos online. The point is I want to run Ubuntu live on ram but also with persistent live and to be able to install new apps. I also already tried installing it on a USB but it takes too long to boot up and it is so slow. Somebody help.

Persistent live drive with a partition for persistence There are some web sites describing  new tools new features in [new versions of] old tools  that can create a persistent live drive from an iso file with Ubuntu 19.10 and the corresponding Ubuntu family flavours.  Why and how does it work? How is it different from earlier methods for persistent live drives? Isn't live the default for a cloned drive?


I have a link sharing site (think reddit). It is hosted on godaddy deluxe shared hosting now. I am planning to migrate it to aws.  I have seen an aws webinar on scaling till 10 million users. But basically it just says beyond an extent you can't scale in a vertical manner so choose to scale in a horizontal manner from the beginning itself.  I don't need to support 10 million users. Assume that i need to support 100,000 users daily. At most the site will have say 1000 concurrent users.  Use Case   Users will post links to the site. Only one in 1000 users will post links. Most users just search the site for links, read the description etc. About 5000 comments will be made on the site every day. It is mainly a text based site. There are very little images on the site except user avatar and banner, both of which are limited at 2MB.  The images are stored in the DB. usual features of a forum like signup,login, account etc are present.   Planned Architecture   1 EC2 instance 1 RDS instance 1 Route 53 Zone 1 Elastic ip 1 s3 (only for backup)   I plan to scale using this simple method -  Start with say t2.micro, as the user base grows simply upgrade the ec2 instance. The same goes for the RDS instances.  I know that 1 EC2 or RDS makes it a single point of failure. If any of these break i plan to terminate that instance and start an identical one from an image/backup. I am okay if the site is offline for 1 hour every 30 days.  Please keep in mind that i have no one to assist me and this is a solo effort. I can find someone to assist on the aws side if it hits users.   Can i support 100,000 users in this manner? At what breakpoints should i upgrade to the next Ec2 instance till the 100,000 users/1000 concurrent users? (eg. Till 5 concurrent users- t2.micro/db.t2.micro, Till 40 concurrent users- EC2 Instance type 2/Rds instance type 2 etc.) Is there anything else that i have not considered/ have to consider before going ahead with this plan?

This is a  about  Related:      I have a question regarding capacity planning. Can the Server Fault community please help with the following:   What kind of server do I need to handle some number of users? How many users can a server with some specifications handle? Will some server configuration be fast enough for my use case? I'm building a social networking site: what kind of hardware do I need? How much bandwidth do I need for some project? How much bandwidth will some number of users use in some application?


In the Star Trek TNG episode "Descent" (part 1 and 2), Lore exploits a weakened state of the Borg collective to become their leader (temporarily).   How much of the collective followed him? I infer that it was only a small portion but it's not necessarily clear in the episode.

Unless I missed something key during Descent 1/2, how is it that the Borg are once again a collective?


How do I show that the reals under addition are not isomorphic to the rationals under addition, and that the rationals under addition are not isomorphic to the integers under addition?  I've tried finding elements with different orders, but for each group, the elements have infinite order. I know all three groups are Abelian. Is it because they won't form a bijection?

Is there a better (or other) way(s) to prove the following statement? Also, the same argument works for multiplicative groups $\mathbb{R}-\{0\}$ and $\mathbb{Q}-\{0\}$, right?       Problem Prove that the additive groups $\mathbb{R}$ and $\mathbb{Q}$ are not isomorphic.   Solution By cantor's diagonal argument, there is no possible bijection between $\mathbb{Q}$ and $\mathbb{R}$. Since an isomorphism needs to be a bijection, there is no possible isomorphism between the additive groups $\mathbb{R}$ and $\mathbb{Q}$.    Thanks


I am looking at taking a job offer from a company based in New York. The position is fully remote and I live in Utah. I have been trying to find information on what my state income taxes will look like if I take the job. What I find online is very confusing. I was hoping for some clear-cut information on what taxes I would be paying. Specifically, would I pay any New York state income tax? I assume I would pay Utah state income tax no matter what since I am a Utah resident. Bonus: If I do pay New York taxes, what rates would I be paying?

I have been down in Florida for the past 3 1/2 years and continue to pay New York state taxes out of the money I earn for a company I work remote for that is in New York.  Should I be paying New York state taxes on this income?  Or do I not need to pay New York state tax because I live in Florida?  Our NY accountant says I need to continue to pay since company is out of NY, however others say I don't need to pay.  Pls advise which is correct. Thank you.


I am having a problem with client application (running on a PC on LAN) connecting to the SQL Server 2008 Express.  The application gets error something like "Server does not exist"  When running the application right on the VM box where SQL server is installed, no problem. Executing the PortQry.exe utility on the server shows that SQL Server is listening on port 1433. The Remote Connection option is checked in the SSMS. So it could be a firewall issue.  But the question is the following:  Is there a command (like PING) I can execute on the client PC on the LAN that will show if the SQL Server is being accessed?  Just so that I can see that "something" is blocking or not the connection. This would be another way of checking it, besides using the application.

I just installed SQL Server 2008 Express on my Vista SP1 machine. I previously had 2005 on here and used it just fine with the old SQL Server Management Studio Express. I was able to connect with no problems to my PC-NAME\SQLEXPRESS instance (no, PC-NAME is not my computer name ;-).  I uninstalled 2005 and SQL Server Management Studio Express. I then installed SQL Server 2008 Express on my machine and elected to have it install SQL Server Management Studio Basic.  Now, when I try to connect to PC-NAME\SQLEXPRESS (with Windows Authentication, like I always did), I get the following message:  Cannot connect to PC-NAME\SQLEXPRESS. A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) (Microsoft SQL Server, Error: -1) For help, click:   When I installed SQL Server 2008, I had it use SQLEXPRESS as the local instance name. As far as I can tell, through SQL Server Configuration Manager, SQL Server is configured to allow remote connections.  When I went to the help link it mentions, the help page suggests the following:   Make sure that the SQL Server Browser service is started on the server. Use the SQL Server Surface Area Configuration tool to enable SQL Server to accept remote connections. For more information about the SQL Server Surface Area Configuration Tool, see Surface Area Configuration for Services and Connections.   Well, as far as I can tell, there is no SQL Server Browser service on my system (looked in MMC for one, couldn't find one).  And the SQL Server Surface Area Configuration tool doesn't exist in SQL Server 2008. So good job there with your help documentation, Microsoft ;-).  I'm at a loss for what to do right now. I had a lot of work I was hoping to get done today after upgrading to 2008 (the person I'm working with got it up and running with no problem and told me it would be easy - he's also far better with database stuff that I am). Does anyone have any idea what might be wrong? I'd really appreciate it. If I can't get this working in a few hours, I'm going back to SQL Server 2005 (if that will even work, gah...).  Edit: I have tried turning Windows Firewall off, and that did not help. Also, I noticed that I do not have a "Data" directory under my SQL Server 2008 install directory tree - could I have possibly set something up wrong when I installed it?


Suppose there are two  elements vertically placed together, like the following image:    The condition is div1's height is auto/dynamic, since it depends on its content.  The question is how to set css style of div2 to make sure the sum of heights of div1 and div2 is fixed, for example:  <div1> and <div2> has total height of 1000px, while div1's height is auto, when div1 has height of 200px, the height of div2 will auto adjust to 1000-200=800px; when div1 has height of 400px, the height of div2 will auto adjust to 1000-400=600px;  Is there any solution about this? I tried to use flex, but cannot figure out how.

I am working on a web application where I want the content to fill the height of the entire screen.  The page has a header, which contains a logo, and account information. This could be an arbitrary height. I want the content div to fill the rest of the page to the bottom.  I have a header div and a content div. At the moment I am using a table for the layout like so:  CSS and HTML    #page {     height: 100%; width: 100% }  #tdcontent {     height: 100%; }  #content {     overflow: auto; /* or overflow: hidden; */ }

...

...

     The entire height of the page is filled, and no scrolling is required.  For anything inside the content div, setting top: 0; will put it right underneath the header. Sometimes the content will be a real table, with its height set to 100%. Putting header inside content will not allow this to work.  Is there a way to achieve the same effect without using the table?  Update:  Elements inside the content div will have heights set to percentages as well. So something at 100% inside the div will fill it to the bottom. As will two elements at 50%.  Update 2:  For instance, if the header takes up 20% of the screen's height, a table specified at 50% inside #content would take up 40% of the screen space. So far, wrapping the entire thing in a table is the only thing that works.


Give a derivation of $\neg R$ from the following premises: $$\{R\leftrightarrow(R\lor(P\land \neg P)), R\leftrightarrow\neg P, \neg P\to(P\leftrightarrow(Q\to Q)), P\to Q\}$$ using the rules found .  My assignment is due today, if someone can help me out. ty Is this correct? I know some dependence columns are wrong.  1 1) R↔(R/lor(P∧¬P)) P 2 2) R↔¬P P 3 3) ¬P→(P↔(Q→Q))  P 4 4)P→Q P 5 5)R P 2 6)R→¬P  2,BE 2,5 7)¬P 5,6,MP 2,3 8)P↔(Q→Q) 3,7,MP 2,3 9)(Q→Q)→P 8,BE 2,3,5 10)¬(Q→Q) 7,9,MT 2,3,5 11)Q∧¬Q 10,NC 2,3,5 12)Q 11,simp 2,3,5 12)¬Q 11,simp 2,3 14)¬R 12,13,RAA 2,15)¬R 5,14,RAA

Give a derivation of $\neg R$ from the following premises: $$\{R\leftrightarrow(R\lor(P\land \neg P)), R\leftrightarrow\neg P, \neg P\to(P\leftrightarrow(Q\to Q)), P\to Q\}$$ using the rules found .  I don't know where to start... Edit:  1 1) R↔(R/lor(P∧¬P)) P 2 2) R↔¬P P 3 3) ¬P→(P↔(Q→Q))  P 4 4)P→Q P 5 5)R P 2 6)R→¬P  2,BE 2,5 7)¬P 5,6,MP 2,3 8)P↔(Q→Q) 3,7,MP 2,3 9)(Q→Q)→P 8,BE 2,3,5 10)¬(Q→Q) 7,9,MT 2,3,5 11)Q∧¬Q 10,NC 2,3,5 12)Q 11,simp 2,3,5 12)¬Q 11,simp 2,3 14)¬R 12,13,RAA 2,15)¬R 5,14,RAA


Say we have a system with a given Lagrangian $L(q_i, \dot q_i, t)$.   A continuous transformation $ Q_i= q_i +εK_i $ is a symmetry when L doesn't change in first order with respect to $ε$. In the same manner, it's a symmetry of action when the action $ S= \int_{t_1}^{t_2} Ldt $ doesn't change in first order.  Is there, given the Lagrangian, a specific method for finding all the symmetries of this Lagrangian/action? If we suppose a random transformation  $ Q= q +εK $ and then demand that it's a symmetry how do we proceed? Do we know what/how many symmetries to expect? Thanks in advance :)  EDIT If it makes things easier, suppose the special case of a body in a homogenous and vertical gravitational field with $L={1 \over 2} m {\dot {\vec r}}^2 -m \vec g \vec r$. How do we find the symmetries of this lagrangian and of its action? I'd prefer an answer to the general case, but solving this example would give me an insight as well.

Assume one has a continuous transformation of fields, and also of coordinates - in case if we consider coordinate transformations as well. Global internal symmetries, rotations, translations, dilatations, whatever, or any other. How do we generally check whether the action is invariant under such a transformation?  I feel like my question is way more basic than Noether theorem, charges, currents, etc.  To be more precise. Let's change the fields (and probably the coordinates) as: \begin{align}     x &\to x + \xi(x)\\     \phi(x) &\to \phi(x) + \delta\phi(x) \end{align} where $\xi(x)$ and $\delta \phi(x) = F[\phi(x),\partial\phi(x)]$ have certain functional form. I would like to know, whether the action \begin{equation}     S = \int \operatorname{d}^D x\, \mathcal{L}[g^{\mu\nu}, \phi(x), \partial\phi(x)] \end{equation} is form-invariant under such a transformation. In other words, whether it will go into something like \begin{equation}     \tilde{S} = \int \operatorname{d}^D \tilde{x}\, \mathcal{L}[\tilde{g}^{\mu\nu}, \tilde{\phi}(\tilde{x}), \partial\tilde{\phi}(\tilde{x})] \end{equation} (notice no tilde above $\mathcal{L}$! I guess, that is form-invariance...)  So far, it seems to me that the obvious option - to calculate $\delta S$ does not give anything (that's what we do when deriving Noether currents). On classical trajectories, we end up with smth like $\delta S = \partial(\ldots)$ - which if of course correct, but does not help  to answer my question at all.  I feel like my question should be related to Killing vectors... In various textbooks I found how the Lie derivatives are applied to the metric in order to determine which transformations preserve it. Seems like I'm interested in a similar procedure for the action.  As usually, any references greatly appreciated.  UPDATE  Since the original question can be answered in a brute force way - "just plug your transformations into the Lagrangian and see how it goes", let me ask it in a slightly more general way:  Given the action, what is the procedure to find all continuous symmetries which leave it form-invariant?


The real problem is this: nothing is working

I have a Nexus 5 phone and ever since I allowed a system update, it won't let me post pictures to Instagram. It keeps talking about turning off a "screen overlay", but then when I try to follow the steps to get to that setting, it just sends me in a loop and doesn't actually let me change anything.  (Click image to enlarge)


Find all the ring morphisms from $ℤ_{15}$ to $ℤ_3$.  I know the axioms that have to be satisfied in order for a function to be a ring (homo)morphism but I don't know how to go about finding them. Any help would be great. Thank you in advance!

Question:      Find the number of non trivial ring homomorphisms from $\mathbb Z_{12}$ to $\mathbb Z_{28}$. ($f$ is not necessarily unitary, i.e., $f(1)$ need not be $1$.)    Suppose $f$ is a ring homomorphism from $\mathbb Z_{12}$ to $\mathbb Z_{28}$.  Consider $f$ as a additive group homomorphism.  Let $k= |\ker f|$ and  $ t = |\operatorname{im}(f)|$. Then $k\mid 12$ and $t\mid 24$ and $kt=12$, by first isomorphism  theorem of groups.  There are two possibilities $k=3$, $t=4$   and $k=6$, $t=2$.  For the first case $f$ should map $1$ to an element of the subgroup generated by $7$ as there is a unique subgroup of $\mathbb Z_{28}$ of order $4$ generated by $7$. For the second case $1$ has to map to $14$, for the same reasoning.  So there are at most two ring homomorphisms from $\mathbb Z_{12}$ to $\mathbb Z_{28}$. Question is how to check the possible maps which are ring homomorphisms.  Thanks.


Sorry for a simple curiosity, Given Unencrypted and encrypted data (AES-GCM) both, is it possible to calculate the Chiper key of AES-GCM ?

At least it's my understanding that AES isn't affected by known-plaintext. Is it immune to such an attack, or just resistant? Does this vary for chosen-plaintext?


I have 12 overhead soft white canned lights in a 10ft ceiling, each casting about 65watts.  A large tinted window is bringing a ton of grey light into a 550 ft room.  So my problem is now the can lights are warming up the grey turning people orange, and the grey natural light I can't warm up so photos look blueish.  What kind of stationary lighting do I need to cancel that grey? How many? Wattage?  Thank you.

I have a dSLR and I often find myself taking pictures of people in 'mixed lighting' environments (e.g. tungsten lighting and daylight, fluorescent and tungsten, or even the ‘nightmare lighting scenario’ of mixed fluorescent, tungsten and daylight). Since white balancing won't work (or at least it won't work completely) to remove the color cast from these sorts of mixed environments, what can I do to manage the multiple types of lighting in my environment?    Asked by :  I was at a wedding recently, and the reception hall had these huge windows that let a lot of sunlight through. The overhead lamps used inside the reception hall had a strong yellow tint to them. Given the two different types of light sources, "white" seems to have a vastly different definition in different parts of the photo. I found that a lot of my photos were near impossible to correct the white balance in post production (I shot in RAW).   Here is an example from the set I shot at the wedding:    If I set the white balance relative to something outdoors, everything inside looks too yellow (as seen). If I set the white balance relative to something indoors, everything that falls in the sunlight looks too blue. Neither looks particularly "good".  So, does anyone have tips for how to handle this sort of situation next time I take a shot? I'll also accept answers that offer post-processing advice.  // As an aside, I'm just an photography hobbyist...not a professional wedding photographer ;)


This is continuation of . The answer by @samcarter works, but there is a loose end: making reference to Example 1 in the continuing example is done by "[myexample]". I was wondering if we can replace it with "[\ref{myexample}]" by modifying the preamble. This makes life a little easier because WinEdt then suggests a list of label after typing the first few letters. Thanks!

I have two examples in Beamer, Example 1 and Example 2. I then would like to have Example 1 (ctd) after Example 2. The following is not working:  \documentclass[notheorems]{beamer} \usetheme{Pittsburgh} \setbeamertemplate{theorem}[ams style] \setbeamertemplate{theorems}[numbered]  \makeatletter \ifbeamer@countsect   \newtheorem{theorem}{\translate{Theorem}}[section] \else   \newtheorem{theorem}{\translate{Theorem}} \fi   \theoremstyle{example} \newtheorem{example}{\translate{Example}}    \setbeamertemplate{theorem begin}{% \begin{center} \begin{minipage}{0.9\textwidth} \begin{\inserttheoremblockenv} {%   \inserttheoremname   \inserttheoremnumber   \ifx\inserttheoremaddition\@empty\else\ (\inserttheoremaddition)\fi% }% }  \setbeamertemplate{theorem end}{% \end{\inserttheoremblockenv} \end{minipage} \end{center} } \makeatother  \addtobeamertemplate{theorem begin}{% \setbeamercolor{block title}{fg=green}% \setbeamercolor{block body}{bg=gray}% \setbeamerfont{block title}{size=\small,series=\bfseries}% }{}  \newtheoremstyle{examplec} {\topsep} {\topsep}% {\upshape}% Body font {}% Indent amount (empty = no indent, \parindent = para indent) {\bfseries\scshape}% Thm head font {.}% Punctuation after thm head {1em}% Space after thm head (\newline = linebreak) {\thmname{#1} \thmnumber{ #2}\thmnote{#3} (ctd)}% Thm head spec \theoremstyle{examplec} \newtheorem*{examplec}{\translate{Example}}  \begin{document} \begin{frame} \begin{example} This is the first example.\label{myexample} \end{example}  \begin{example}  This is the second example. \end{example}  \begin{examplec}[\ref{myexample}]  Continuing first example. \end{examplec}  \end{frame} \end{document}   This will produce the following:    What I want is: instead of Example (1), having Example 1 (ctd).  I noticed the solution at  but it does not seem to work if I keep my configurations in the preamble (which is why MWE is a bit long) -- I want to keep the (ctd) part.   Your help is much appreciated. Thanks!


In response to questions like , can we implement a feature whereby questions cannot be posted to certain tags?  For e.g., if someone attempts to post a question to  on SO, they (questioner) get a response:     This tag (and the questions) exist for historic reasons. Such questions are no longer on topic at SO and should be asked at X.SE, following the guidelines established at X.SE/faq   where X.SE depends on the tag. This will prevent crap on SO, result in SO getting less flak for migrating crap and prevent "why was my question closed?" questions on meta.

Based on my answer , I would like to propose the implementation of a tag black list.  The black list should contain a list of tags that should NOT be used on the site and disallow people with tagging rights to use these tags, for example the case of using the belongs-on tags.  I would also suggest increasing the tagging rep limit however this was previously covered .   Additional Options  As mentioned by  the list should only be accessible by moderators and possibly 10K moderators to ensure that the list is kept tidy. However for 10k moderators a voting process will be put in place to add a tag to the blacklist.  The list should also be updated when moderators merge tags. The removed tag should automatically be added to the black list.  Blacklisted tags can appear as strikethroughs on the tag field when editing or adding a new question, and be validated accordingly.  Additional Nice to Have  When tags are edited they should not bump questions, as this ends up creating a lot of noise on the homepage.


I'm not good at physics, but I'm trying to make a lantern. So I have an LED with this characteristics:    N = 3 Watt I = 0.7 Ampere U = 3.4-3.6 Volt   So I connect it to 6V battery, but need ~3.5 V. What type of resistor do I need?  I calculated internal resistance with R = U / I and got 3.6 / 0.7 = 5.14 Ω.  And using this formula I = 𝛆 / (R + r) I got total resistance of 6 / 0.7 = 8.57 Ω. Here 8.57 - 5.14 = 3.42 Ω of external resistor. Am I right?

I need to work out what resistor I need for a series circuit containing 3 LEDs of 2 different types, and a 9v battery.  I can do the maths, but I need to check I'm doing it right as I'm trying to learn this from what I can google!  LED1 VF = 3.2V @ IF = 20mA LED2 VF = 2.2V @ IF = 20mA  Both LEDs have a Forward Current of 20mA at these Forward Voltages.  The circuit will contain 2x LED1 and 1x LED2.  So, using R = (VS - VF) / IF, do I calculate the total VF as 3.2V + 3.2V + 2.2V, therefore VF = 8.6V?  Using the figures I have, I get:  (9 - 8.6) / (20 / 1000) = 20 ohm, so I'd need a 20Ω resistor?  Also, can anyone advise what type of resistor would be best?


I vaguely remember this fantasy-esque miniseries (or was it a made for TV movie?) that featured a society where some of the worst criminals were punished with immortality along with imprisonment as a form of ultimate punishment.  Basically, if I recall correctly, being immortal was seen as a curse and once you were immortal you could be kept imprisoned by other immortals for millennium or longer.    Offenders were made immortal by being strapped to a chair with their mouth forced open and some kind of lizard-like humanoid would spit/excrete some kind of mucusy substance into their mouth, kind of gross.  I only saw a few parts of the show so I could be misremembering or misunderstanding any or all of it.  But I do distinctly remember immortality being administered as a punishment to at least one character.  I think this miniseries or TV movie was made some time in the 90s, but it could be late 80s for all I know.

I remember watching something on TV that seemed like it was the first episode of a TV series.  It might have just been a pilot of something that got cancelled, or I guess it's also possible it was a miniseries or made-for-TV movie.  I believe this was in the mid-90s, but definitely at some point in the 90s, when I saw it.  I'm guessing that's also when it was made, because the production quality seemed decent to me at the time--nothing special, just didn't seem dated.  Anyway, there was a young doctor just arriving fresh for his first post, in some backwater or frontier planet or region--I remember some sort of contrast between his training and equipment and their (wooden?) housing.  I think he was resentful about the post.  It also turned out to be quite dangerous.  The locals suffer periodic attacks from riders on horseback who emerge from some sort of rift--like a tear in space/time sort of portal.  So there's some sort of sci-fi frontier medicine vibe going on.  Finally, I also remember there was some surgery and/or combat scenes with a bit of blood.  I was young and it was too much blood for me at the time, so I changed the channel and never managed to find this again...  Any ideas what this was?


I have Windows 10 and Ubuntu 16.04 (I did a UEFI install ) How can i uninstall ubuntu, delete GRUB and recover the stock windows boot loader ?

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


I'd like some help on proving the following inequality $$ \prod_{i=1}^{n}\left(1+a_{i}\right) \ge \bigg(1 + \prod_{i=1}^{n} a_{i}^{1/n}\bigg)^{n}, $$ given that $ a_{i} > 0\,\, \forall\, i\in\{1,2,\cdots,n\} $.  I tried to use AM-GM inequality on the right-hand side, but without success. Any help would be appreciated.

I can show that for $x > 0$ and $r_{i} > 0$ we have $$ \left(\, x + r_{1}\,\right)\ldots\left(\, x + r_{n}\,\right)\ \geq\ \left[\, x + \left(\, r_{1}\ldots r_{n}\,\right)^{1/n}\,\right]^{n}.$$ However, I can't do this using straight up induction, strong or weak. Can someone do this?   You can show the inequality holds for $n$ if it holds for $n+1$ using $r_{n+1} = (r_1 \cdots r_n)^{1/n}$, so going down isn't a problem, but going up has eluded me. Additionally, you can show that if it holds for $n=a$ and $n=b$ then it holds for $n=ab$. Using powers of two and the above is sort of a way to prove the above by induction but it certainly isn't "normal".  You can also prove the above using Lagrange multipliers (which isn't surprising). The last proof I know is where you compare coefficients of $x^k$ and use the AM-GM inequality.


I only want to read the first line of a text file and put that first line in a string array.  This is what I have but its reading the whole file.  ex text in myTextFile:   Header1,Header2,Header3,Header4,Header5 1,2,3,4,5 6,7,8,9,10      String line= System.getProperty("line.separator"); String strArray[] = new String[5];   String text = null; BufferedReader brTest = new BufferedReader(new FileReader(myTextFile));     text = brTest .readLine();         while (text != line) {             System.out.println("text = " + text );              strArray= text.split(",");          }

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


I am trying to convert a script made for a tool called Noesis to Blender, so far I have gotten it to work, although I cannot find an alternative to this line of code for blender: material.setTexture() I would imagine there is something similar to this, but I can't find anything. So is there an alternative to change the material to an image texture and then assign an image to it, preferably without the use of nodes? Edit: for the most part, I have fixed it, yeah, you have to use nodes. Thanks to everyone that helped out.

How can I define the different properties of an Cycles/Eevee material? Such things as glossy, glass, diffuse, RGB-color, emissive via python scripting?


string input = "

         Text A

                     Text B

                     Text C

         Text D

"   I have a series of tables in the above string format.  I want to extract out the content in the first level of all
, where the expected extracted content is:  Text A

         Text B

         Text C

  Text D   I have the following Regex that describes what I am trying to do  var regexTableRow = new Regex("
(.*?)
");          var regexMatches = regexTableRow.Matches(htmlInput);          var tableRows = new List<string>();          foreach (Match match in regexMatches)         {             // Get a row of

 out             var value = match.Value;              tableRows.Add(value);         }   Where the Regex fails is it extracts the
 from the inner tables instead of outer tables. How do you make Regex focus only on outer tables during extraction?  Thanks.  [Edit] - Thank you, I will use HtmlAgilityPack instead. Similar issue is being faced with this code:  var htmlDocument = new HtmlDocument();             htmlDocument.LoadHtml(htmlInput);              var output = htmlDocument.DocumentNode                 .SelectNodes("table/tr");   Where the inner tables are being picked up instead of the outer tables.

I'm looking for a library/method to parse an html file with more html specific features than generic xml parsing libraries.


It's a .net core project running on a Mac. I've a custom Exception class that I'm serializing as JSON as output in case of an error.    public class HttpException : Exception {     private readonly int statusCode;      public HttpException() {}      public HttpException(int statusCode, string message) : base(message) {         this.statusCode = statusCode;     }      public int StatusCode {get {return this.statusCode;}} }   Code related to json serialization  Exception exception = (Exception)serviceRequest.ResultData; MemoryStream memoryStream = new MemoryStream();   DataContractJsonSerializer dataContractJsonSerializer = new DataContractJsonSerializer(typeof(Exception));     // it fails here dataContractJsonSerializer.WriteObject(memoryStream, exception);     byte[] json = memoryStream.ToArray();   memoryStream.Close();   Console.WriteLine(Encoding.UTF8.GetString(json, 0, json.Length));      System.Runtime.Serialization.SerializationException: Type 'Service.Model.Exceptions.HttpException' with data contract name 'HttpException:' is not expected. Add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer.      at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeAndVerifyType(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, Boolean verifyKnownType, RuntimeTypeHandle declaredTypeHandle, Type declaredType)   Edit  Trying to use System.Web.Extensions but have squiggly lines.

More specifically, when the exception contains custom objects which may or may not themselves be serializable.  Take this example:  public class MyException : Exception {     private readonly string resourceName;     private readonly IList<string> validationErrors;      public MyException(string resourceName, IList<string> validationErrors)     {         this.resourceName = resourceName;         this.validationErrors = validationErrors;     }      public string ResourceName     {         get { return this.resourceName; }     }      public IList<string> ValidationErrors     {         get { return this.validationErrors; }     } }   If this Exception is serialized and de-serialized, the two custom properties (ResourceName and ValidationErrors) will not be preserved. The properties will return null.  Is there a common code pattern for implementing serialization for custom exception?


i have a Visa type C , Multiple Entry with 1 year of validity to the Netherlands(issuing Country), so i want to visit first Spain for a week and then go to my destination which is the Netherlands. can i do this without having any problem in my upcoming application ?

In case, if I get a multiple-entry Schengen visa in one of the embassies in Ukraine, Kyiv - should my first trip be to the country which issued the visa?  Any there any requirements of this sort? Does this condition vary depending on embassy which issued the visa?  What are the possible consequences on not visiting that country first? Does it somehow depend on country where the embassy is (i.e. non-Schengen and not EU members)?


Well, the title basically explaines my problem: Adding footnotes inside footnotes doesn't seem to work... Can you help me?

How can I make a footnote to a footnote? E.g.,  Playfair's axiom\footnote{so called in honor of mathematician John Playfair, etc, etc., but was actually discovered by Proclus\footnote{Greek mathematician, etc, etc.}}


Are there hash functions that dynamically take integers a and b, and output h(a) and h(b) such that if a>b we have h(a) > h(b)?

Is there a construction of an order preserving hash function that keeps the preimage property of a crypto hash function? By order preserving hash function (OPHF) i mean for $x<y$ then $OPHF(x) < OPHF(y)$


I'm preparing a farewell email to my colleagues and want to use this phrase:  "Not only I am proud of the work we have accomplished together but also I have learned so much from you about statistics, sciences and beyond."  I'm not a native English speaker and wondering whether this is a conventional way. Could somebody have me some suggestions.  Thanks in advance.

I'm trying to figure out how to use "not only... but also" properly. Basically, my goal is to combine two clauses by using "not only".  For negations, I've figured out two styles that both sound correct:   He knew that if he fractures his finger, not only would he not be able to compete in the water polo tournament, he would not be able to take the SAT on Monday, either. He knew that if he fractures his finger, neither would he be able to compete in the water polo tournament, nor would he be able to take the SAT on Monday.   However, I don't know how to form a sentence that does not include a negation while using "not only". Here are a few possibilities that I've considered:   Thanks to his remarkable performance on the SAT, not only was he accepted into Harvard, but he was also given a full scholarship. Thanks to his remarkable performance on the SAT, not only was he accepted into Harvard, but he was given a full scholarship. Thanks to his remarkable performance on the SAT, not only was he accepted into Harvard, he was given a full scholarship. Thanks to his remarkable performance on the SAT, not only was he accepted into Harvard, he was also given a full scholarship.   In those four possibilities, I'm varying the usage of "but" and "also" in the last clause.  What is the proper usage of "not only"?


Cannot Complete Login      Detected an attempt to send an assertion when the identifier () is not owned by the logged in user.      If you believe you encountered this message in error, please report it.   Login page:

The SourceForge signon page says I can associate an OpenID with my existing SourceForge account:    I enter my currently-signed-in SourceForge account password I select the custom OpenID URL and enter https://openid.stackexchange.com I'm redirected to https://openid.stackexchange.com/account/login?<session key bits> I enter my openid.stackexchange.com login information there I get the error message:     Cannot Complete Login      Detected an attempt to send an assertion when the identifier () is not owned by the logged in user.    I don't understand what that means.


I'm not sure if this is for everyone, but the "n question(s) with new activity" notification doesn't show up for me in Stack Overflow. It's really inconvenient having to reload the page again and again, when a simple click can load the questions for me... It works for MSO and English.SE -  But doesn't work for Stack Overflow. It used to work before, but now it doesn't show up anymore. Can this be fixed? It stopped working a couple of days ago... Note: I've looked at other similar questions and yes, my browser (Chrome) supports WebSockets -

We have deployed a new feature that hopefully help with keeping you instantly updated as new questions and answers are posted.  All sites except for Stack Overflow have a new activity indicator on the homepage which will show when new posts are asked or answered.    We have also enabled updates on the questions page for the newest and active tabs for all sites except Stack Overflow.  If you open a browser to these tabs you will receive instant notifications when new questions are asked or answered.    Stack Overflow has a massive amount of activity so we have decided to limit this feature to tags only.  Both the "newest" and "active" tab will have updates after first selecting a tag or tag combination.    We recently added support for new answers and comments:        Now for the gotchas - in order to use this feature you must have a browser that supports web sockets.  See:   for a list of browsers that currently support web sockets.  UPDATE  As a few have mentioned below we are now experimenting with updating comment counts, votes on a post, and your reputation score.


I'm involved in a project that will deploy approximately 400 android tablets. All the devices are on the same network. Is there an easy way to centrally manage the following:  Creating and updating policies to restrict users from launching apps or updates Update a custom written application  Set device into kiosk mode and auto start an app  Any help would be appreciated.

I have 50 Android tablets. I want to be able to control from a central place the following things on the devices:   General settings like date-time, unlock method, display sleep time etc; Chrome specific things like clearing the history and cookies, saving bookmarks, setting the homepage etc; The ability to install or uninstall apps on particular device or all of them.   So I need a mini SCCM for Android. Is there such a thing?


Today when I logged into my Stack Overflow account it showed me that I had got one reputation point. But when I clicked on the "Recent achievements" button on top bar there was no explanation for it. This is how it looked like to me:    Any one knows why was I awarded one reputation point?

In the top bar, the green “achievements” number shows +14. But when I open the dropdown, I see four items totalling +20. Why does the total not match the sum of the items?    No lower entries were highlighted.


I just upgraded to ubuntu 14.04 from ubuntu 12.04 (Which I loved) and now, I cant install apt-fast. My net connection is very slow and I want to download using apt-fast but whenever I add the apt-fast ppa and update and try to install it, It says   package apt-fast not found  How do I fix this? thank you.  I really appreciate The effort made by askubuntu (Which includes you awesome people ;)) To help me. My problem has already been answered. Here is a screenshot of my software sources. The person who answered my question has apparently removed the comment that answered my question but here is the repository that helped me add apt-fast  sudo add-apt-repository ppa:saiarcot895/myppa  So if this helps I would like to upvote each and every person who helped me and I will accept one answer too, Just give me some time to test both of them ;)  anyway thank you guys to help me. You are awesome :-) XD

Several times over the past couple years, I've heard of people using apt-fast for updating and installing packages, but I'm not really sure what it does.  I think I've traced its origin to , and it seems to be a script that speeds up apt-get operations.  What exactly does the script do? Are there any potential downsides to using it? If not, why isn't everyone using it?


I want to write this algorithm (recursive) in latex but I don't know how to do it. I have attached image of the algorithm. Please help me with the code. I am using algorithm2e package. Thanks!!

I have defined my own language whose syntax is very close to the one of Pascal. I would like to type the following program for instance. Many people use the packages algorithmicx or algorithm2e to print programs, but it seems that we have to use their specific keywords of its syntax like procedure, end while.  I just want to indent spaces when needed, and bold some words when I want (sorry that I could not bold letters in the following figure). Do I have to use  texttt for each line? Also, with verbatim, I could not bold words...  Also, as the program is not large, I would need to put it on the left side of the page, and leave space for some explanasion text on its right hand side. So I  guss I need to get them all together, and use multicols.  Could anyone help?  program test                                      some text here var   i : integer;                                    ...    b : boolean; begin    i := 1;                                        ...    b := true;    while i < 15 do       i := i  + 1;       b := not b                                  some text here    od end   Edit1: Following @Werner's tabbing solution, I have made the code a minipage:  \begin{minipage}[t]{0.48\linewidth}% \begin{tabbing} Werner's solution \end{tabbing} \end{minipage}\hfill \begin{minipage}[t]{0.48\linewidth} a paragraph \end{minipage}   Actually as the code shows, I want the texts to be another separated minipage on the right hand side of the code. I have then 2 questions:   is it reasonable to make 0.48\linewidth instead of 0.5\linewidth? 0.48\linewidth is a conventional choice? is it possible to make a frame around the code, and use \caption and \label to make it a reference (I prefer figures)?


This is almost certainly a dumb question, but... say I have Windows 7, with some anti-virus software installed, and I am using Microsoft's  to run some legacy applications  as well. Is there any reason why I would want to install an anti-virus program in XP mode as well?

Does the Virtual PC XP-Mode (or any other virtualized mode) require safety measures, such as antivirus or a firewall?  I'm just wondering if the XP-Mode would be a large security loophole, since it's so much more integrated into Windows 7. Actually I'm wondering the same for Portable Ubuntu, are their any safety measures I should undertake, so that I don't open a backdoor on my computer.


If $G$ is a nontrivial group that is not cyclic of order 2, then $G$ has a nonidentity automorphism.  This is the exercise of hungerford algebra in the chapter $IV$ MODULES. Can you help me please?

Well, this is an exercise problem from Herstein which sounds difficult:   How does one prove that if $|G|>2$, then $G$ has non-trivial automorphism?   The only thing I know which connects a group with its automorphism is the theorem, $$G/Z(G) \cong \mathcal{I}(G)$$ where $\mathcal{I}(G)$ denotes the Inner- Automorphism group of $G$. So for a group with $Z(G)=(e)$, we can conclude that it has a non-trivial automorphism, but what about groups with center?


Please do help me on how to increaase my innodb_log_file_size

So I'm fairly new to tuning InnoDB. I'm slowly changing tables (where necessary) from MyIsam to InnoDB. I've got about 100MB in innodb, so I increased the innodb_buffer_pool_size variable to 128MB:  mysql> show variables like 'innodb_buffer%'; +-------------------------+-----------+ | Variable_name           | Value     | +-------------------------+-----------+ | innodb_buffer_pool_size | 134217728 | +-------------------------+-----------+ 1 row in set (0.00 sec)   When I went to change the innodb_log_file_size value (example my.cnf on  comments to change the log file size to 25% of the buffer size. So now my my.cnf looks like this:  # innodb innodb_buffer_pool_size = 128M innodb_log_file_size = 32M   When I restart the server, I get this error:      110216  9:48:41  InnoDB: Initializing buffer pool, size = 128.0M   110216  9:48:41  InnoDB: Completed initialization of buffer pool   InnoDB: Error: log file ./ib_logfile0 is of different size 0 5242880 bytes   InnoDB: than specified in the .cnf file 0 33554432 bytes!   110216  9:48:41 [ERROR] Plugin 'InnoDB' init function returned error.   110216  9:48:41 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.   So my question: Is it safe to delete the old log_files, or is there another method to change the innodb_log_file_size variable?


In the original matlab code I commented it using characters such as "åäö" creating the following error:  Package inputenc Error: Invalid UTF-8 byte sequence.  when using \lstinputlisting[style=Matlab-editor]{example.m} Indeed the characters doesn't show up when compiling, but everything else works. Is there anything I can do here (other than deleting the characters)?

I want to append some matlab code to a tex document and I use the matlab-prettifier package for that. I updated my miktex installation yesterday and I am now forced to use the \UseRawInputEncoding code line. Everything works fine for the German and Latin symbols I have in my matlab code, except for the degree sign, which comes out as an r with an inverted hat above, regardless of whether I use the literate substitution approach or not. Any suggestions on how to solve this elegantly would be welcome. Here is my MWE: \documentclass{article}  \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage[framed,numbered]{matlab-prettifier} \usepackage{textcomp}   \UseRawInputEncoding  \begin{document}  \lstset{   language=Matlab,   style=Matlab-editor,   basicstyle=\mlttfamily\footnotesize,   literate=%     {°}{\textdegree{}}1% }  \lstinputlisting[]{matlab_code.m}  \end{document}  and my matlab_code.m file reads as: % ----------------------------     % Rö and Mé (T = 23°C) var_1 = 10;  Obviously, I can write degree instead of ° in the matlab file and substitute that by \textdegree, but I would like to bring changes to the matlab code to a minimum and actually use the degree symbol, whose use comes much more naturally than that of the corresponding text. Is it possible to directly read in tex and via matlab-prettifier a ° symbol written on a matlab file, rather than "going around" by substituting the corresponding degree text by the actual symbol?


I am not able to make sense of the first line inside the loop body.  How to interpret this statement:         printf("%d", i++[a]);      #include <stdio.h>      int main()     {          int a[5] = {1,2,3,4,5};          for(int i=0; i<5; i+2){             printf("%d", i++[a]);             printf(",%d",i);         }          return 0;     }   Output  1,12,23,34,45,5

As Joel points out in , in  (aka: K & R), there is mention of this property of arrays in C: a[5] == 5[a]  Joel says that it's because of pointer arithmetic but I still don't understand. Why does a[5] == 5[a]?


Hello helpful community, I am faced with an issue while using a matrix of nodes in Tikz. When I write something in the nodes, they shift. Here is a MWE :     \documentclass{standalone} \usepackage[utf8]{inputenc}  \usepackage{tikz} \usetikzlibrary{matrix}  \begin{document}  \begin{tikzpicture}     \matrix (magic) [matrix of nodes,nodes={minimum width=1cm,minimum height=1cm,draw,very thin, },draw]     {           {} & {00} & {01} & {11} & {10}\\          {} & {} & {} & {} & {}\\     }; \end{tikzpicture}  \end{document}  And its output :  If you haven't tried online editing for latex, you should give a try to overleaf, here is my code on there :

I wanted to draw an almost empty matrix of nodes with TikZ similar to the left most one below. All nodes would have same size (through minimum width and minimum height) and no separation between columns and rows. But when I include a text which needs two lines I obtain the central matrix and, if the text just needs one line the right most one. I don't know what's wrong. Do you? I'm using CVS version of TikZ.  \documentclass[tikz,border=2mm]{standalone} \usetikzlibrary{matrix}  \tikzset{ proces/.style={draw, minimum height=15mm, minimum width=2cm, outer sep=0pt, text width=1.5cm, align=center} }  \begin{document} \begin{tikzpicture}  \matrix (A) [matrix of nodes,nodes=proces,nodes in empty cells] {  & \\  & \\ };  \begin{scope}[xshift=4.5cm] \matrix (A) [matrix of nodes,nodes=proces,nodes in empty cells] {  & OOO OOO \\  & \\ }; \end{scope}  \begin{scope}[xshift=9cm] \matrix (B) [matrix of nodes,nodes=proces,nodes in empty cells] {  & A \\  & \\ }; \end{scope}  \end{tikzpicture} \end{document}


I am using sed for string replacement in a config file.  User has to input the string salt and then I replace this salt string in the config file:  Sample config file myconfig.conf  CONFIG_SALT_VALUE=SOME_DUMMY_VALUE   I use the command to replace dummy value with value of salt entered by the user.  sed -i s/^CONFIG_SALT_VALUE.*/CONFIG_SALT_VALUE=$salt/g" ./myconfig.conf   Issue : value of $salt can contain any character, so if $salt contains / (like 12d/dfs) then my above sed command breaks.  I can change delimiter to !, but now again if $salt contains amgh!fhf then my sed command will break.  How should I proceed to this problem?

In my bash script I have an external (received from user) string, which I should use in sed pattern.  REPLACE="<funny characters here>" sed "s/KEYWORD/$REPLACE/g"   How can I escape the $REPLACE string so it would be safely accepted by sed as a literal replacement?  NOTE: The KEYWORD is a dumb substring with no matches etc. It is not supplied by user.


I have two computers (home and work) that I want connect to VPN. Both computers are behind NAT. I have no access to network configuration so configuring VPN server on router is not possible. Is there free service or software that know's how to do that? I use Windows at work and Mac at home.  I know that Hamachi could do that but its quite expensive.  Thank you for your help.

I have a PC running Windows Vista Home Premium with Norton Internet Security 2009. I like to help my father and sister by connecting their PCs over the internet and taking full control. My father has Windows Vista Home Premium and my sister has Windows XP SP3. Both of them are using McAfee Internet Security 2009. One of my friends recommended me to use TeamViewer. I didn't try it yet. Any comments for this work and for any possible adjustments in both security programs and OS?


recently I encountered this problem: "Show that a rectangle can be partitioned into finitely many squares if and only if the ratio of its sides is rational."  I have found the a solution which I need help to understand:     Clearly, every rectangle with rational ratio of sides can be partitioned into finitely many equal squares. Thus, the interesting part of the problem is the "only if" one.   Proof via Dirichlet's simultaneous rational approximation theorem   Without loss of generality, we may assume that both sides of our   rectange are greater than $1$. We can choose a positive integer $q$   such that the product of every coordinate of every vertex of every   square in our partition becomes almost an integer after multiplication   by $q$. So, we may assume that all these coordinates differ from   integers by, at most, $\frac 15$. Now let $a$ and $b$ be the   horizontal and the vertical side of our rectangle, respectively, and   let $s_i$ be the sides of the squares in the partition. Denote by   $\tilde x$ the nearest integer to $x$. Now, draw the horizontal lines   at all half-integer heights (i.e., the heights $\pm\frac 1 2,\pm\frac  3 2,\dots$) and look at the total length $L$ of these lines within our   rectangle. On one hand, we have $L=a\tilde b$. (There are $\tilde b$   lines intersecting our rectangle and each of them intersects it by an   interval of length $a$.) On the other hand, looking at what happens in   each square, we get $L=\sum_i s_i\tilde s_i$. Thus $a\tilde b=\sum_is_i\tilde s_i$. Similarly, drawing the vertical lines through   half-integer points, we arrive at the identity  $b\tilde a =\sum_i  s_i\tilde s_i$. Thus $a\tilde b=b\tilde a$, i.e., $\frac a b=\frac  {\tilde a}{\tilde b}\in\mathbb Q$.   I didn't understood why did he had to use Dirichlet  theorem in order to draw line on each side, particulary I didnt understood why did he had to do this and how everything in this part connected:     Without loss of generality, we may assume that both sides of our   rectange are greater than $1$. We can choose a positive integer $q$   such that the product of every coordinate of every vertex of every   square in our partition becomes almost an integer after multiplication   by $q$. So, we may assume that all these coordinates differ from   integers by, at most, $\frac 15$.   If anyone can please explain it, it would be great, thanks  reference for the problem and solution:   I’m asking about the answer he gave, not about any other solution...

For what positive real numbers $x,y$ can an $x\times y$ rectangle be partitioned into a finite number of squares?  When $\dfrac{x}{y}$ is a rational number, it is not hard to see that we can partition it.  Also, we can scale the width to $1$, so, say we're dealing with a $1\times c$ rectangle. For what values of $c$ can we do the partition?


I'm using nginx as a load balancer for few http servers (nodejs mostly).  I was wondering if anyone here knows a module (or a way) for nginx to inform (preferably http/s but email is also ok) that one of the instances (or more) is down. I've found many modules that enable me to configure the health check behaviour, but I need something to inform me that a server is down in some way.

For a more comprehensive list of monitoring tools and their features, check out .   As the question states, what are the most commonly used tools used for this task and what are their strengths and weaknesses?


I wish to know the default kernel version that comes with Ubuntu 16.04.6

Is there a list of Ubuntu versions with default corresponding Linux kernel versions somewhere?  I would specifically like to know the most recent version of Ubuntu that still used Linux Kernel 2.x.


Alright, I have a function   function foo(input) {     input = input.split("\n");     console.log(input); }   and the input is 'alert("gsasdgasdg")' so foo('alert("gsasdgasdg")') the output I get when I run it in nodejs is the expected output: [ 'alert("gsasdgasdg")' ] ` Now I will add a simple loop,   function foo(input) {     var output = "";     input = input.split("\n");     console.log(input);     for (var i in input) {         console.log(input[i]);     } }   Now I get the first console.log output as [ 'alert("gsasdgasdg")' ]  (expected) but there should be only one console.log when it loops through the array, what I get is alert("gsasdgasdg")  (expected) and then [Function] as far as I know nodejs should have not of converted this string into a function, any insight that explains why this happens?

I've been told not to use for...in with arrays in JavaScript. Why not?