I need to install node in my system (Ubuntu 16.04) so I type:  sudo apt-get install nodejs   but I get this error:

I am using 15.04.   So I'm working with git and I installed the standard version. I set up the ssh keys and was able to clone one of my repositories to the correct folder. Everything was working great and then I decided it was a good idea to install more packages. I ran sudo apt-get install git-all. I'm looking at error codes now having to deal with upstart.  start: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused No apport report written because the error message indicates its a followup error from a previous failure. dpkg: error processing package runit (--configure):  subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of git-daemon-run:  git-daemon-run depends on runit; however:   Package runit is not configured yet.  dpkg: error processing package git-daemon-run (--configure):  dependency problems - leaving unconfigured Errors were encountered while processing:  runit  git-daemon-run E: Sub-process /usr/bin/dpkg returned an error code (1)   This is what happens when I even update/upgrade my system. At this point all I'm looking to do is be able to install software and update my current software. Is there any way I can potentially reverse this issue or at least correct it?   Edit: Thankfully this issue was solved only a day or two after it happened. The accepted answer worked perfectly and took care of my issue


I need to bypass or find a way to make a zte prestige w/o sim card boost (mobile) into a wifi phone or a phone that can at the very least connect to wifi for internet. it will connect to wifi but it wont open anything so there's no way to get internet or get to a browser because of FRP Google Lock. Anyone know how I can use the internet at the very least and/or bypass the google frp or get internet browsing capabilities? Thank you, appreciate any help.

I won a Samsung Galaxy S6 Edge, signed into it with my Google account, played around with it, wiped it, and sold it.  Now the person can't get past setup because it's saying he must login with an account previously synced to the phone.   Is there anything I can do from my side to remove this lock?


What is the difference between a video game developer and a video game designer?

Gameplay programmers write game code, but so do game designers and developers. Where is the line drawn? What skills do gameplay programmers use that game designers or developers do not?


In bash, I would like to specify all .jar files under a directory to the option -cp of javac (and later java when running the compiled program).  But   $ javac  -cp /home/hibernate-release-4.3.11.Final/lib/required/*.jar *.java javac: invalid flag: /home/hibernate-release-4.3.11.Final/lib/required/dom4j-1.6.1.jar Usage: javac <options> <source files> use -help for a list of possible options   Is it because the expansion of *.jar files are  separated by  but not : which is required by -cp?  Is there a way that works without me to manually specify all the .jar files under a directory?  Thanks.

Is there a way to include all the jar files within a directory in the classpath?  I'm trying java -classpath lib/*.jar:. my.package.Program and it is not able to find class files that are certainly in those jars.  Do I need to add each jar file to the classpath separately?


Find:$$\sum_{k=1}^{n} \binom{n}{k}k^{r}$$      For r=0 the sum is obviously $2^{n}$.  For r=1 the sum is $n2^{n-1}$.  For r=2 the sum is $n(n+1)2^{n-2}$.  Here's what I've tried:  $$\frac{d(1+x)^{n}}{dx}=n(1+x)^{n-1}=\binom{n}{1}+2\binom{n}{2}x+3\binom{n}{3}x^{2}+\cdots+n\binom{n}{n}x^{n-1}$$  $$\frac{d[x\cdot n(1+x)^{n-1}]}{dx}=\binom{n}{1}+2^{2}\binom{n}{2}x+3^{2}\binom{n}{3}x^{3}+\cdots+n^{2}\binom{n}{n}x^{n-1}$$  So if we continue like this and put x=1 we will get our result.However I cannot generalize this.  I think the answer has something to do with the Stirling Numbers of the Second kind.          Another way to present this question:     Find $A_{1},A_{2},\cdots ,A_{r}$ such that $$k^{r}=A_{1}k+A_{2}k(k-1)+A_{3}k(k-1)(k-2)+\cdots$$      If someone can answer the second question I can solve the first one.

Is there a closed-form expression for the sum $\sum_{k=0}^n\binom{n}kk^p$ given positive integers $n,\,p$? Earlier I thought of this series but failed to figure out a closed-form expression in $n,\,p$ (other than the trivial case $p=0$).  $$p=0\colon\,\sum_{k=0}^n\binom{n}kk^0=2^n$$  I know that $\sum_{k=0}^n\binom{n}k=2^n$ and $\sum_{k=0}^nk^n=\frac{k^{n+1}-1}{k-1}$ but I am unsure of whether these would be of much use now.    Additionally, what about the similar series $\sum_{k=0}^n\binom{n}kk^n$ where $p=n$?


could someone help me with calling the first constructor and putting it in the second and third? I may have some problems with the syntax, it seems...

Is it possible to call a constructor from another (within the same class, not from a subclass)? If yes how? And what could be the best way to call another constructor (if there are several ways to do it)?


I've read through the standard explanation of the electric field due to a spherical shell with uniform charge density. This explanation argues that because a Gaussian surface inside the shell encloses zero charge, by gauss' law, the electric field must be zero here. However, shouldn't the statement actually be that the flux is zero here? For example, a Gaussian sphere enclosing no charge above an infinite plane has zero net flux through it, and so it satisfies Gausss' theorem, but inside the sphere, the electric field is still the standard field due to an infinite sheet, no? So doesn't the argument re the spherical shell only rule out that the flux thru a gaussian surface inside the shell will be zero, and not that the field there is zero?

If you have a conducting hollow sphere with a uniform charge on its surface, then will the electric field at every point inside the shell be 0. The reason the electric field is 0 at the center is clear from the symmetry of the sphere, but for a point at a certain distance from the center, shouldn't a net electric field exist?  I saw a similar question on the site but it was vaguely explained.


I'm trying to find the word: <*hasburnt*> in the string below using the this regex: <\*.*(bur).*\*>  But it gives me both <*hasburnt*> <*electrical*>.  How do I just get <*hasburnt*> ?     bench testedstarter, starter just makes noise, and <*hasburnt*>   <*electrical*> smell.

I have this gigantic ugly string: J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM J0000010: Project name: E:\foo.pf J0000011: Job name: MBiek Direct Mail Test J0000020: Document 1 - Completed successfully  I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time). Here's the regex I've been playing with: Project name:\s+(.*)\s+J[0-9]{7}:  The problem is that it doesn't stop until it hits the J0000020: at the end. How do I make the regex stop at the first occurrence of J[0-9]{7}?


I already know how to set someone to auto-follow a record based on specific criteria (record created, modified, etc) by inserting records into the EntitySubscription object.  What I am trying to accomplish is a process in which, for a specific internal object, anyone who is @Mentioned on a chatter text post that is related to that object type will automatically become a follower of the record that they were mentioned in.  I can query for the information I need from the FeedItem object with [SELECT Id,ParentId,Body FROM FeedItem WHERE Type = 'TextPost'], but the body looks like this:     @Person One @Peron Two @Person Number Three can one of you provide me with a specific account that you are referring to?     Issue: I don't use regex often, but figured it would be useful here, however my problem is that there isn't really any clear 'line in the sand' in the Body of the FeedItem for me to tell the regex when to start/stop and guarantee that I've captured the full name of the user, and without the full name of the user I can't properly query for their User Id and insert their EntitySubscription record(s).  In my example above you'll note that I can't just rely on the two words that immediately follow an @ symbol, because there are some users who have a multi part name (Morgan Del Ray, as an example). I was hoping that the @Mentions would be formatted as @[Mention] so that I could use the [ ] as my limiters, but alas it is not.    Question: Is there any way I can guarantee this functionality will capture the full name using an advanced form of regex? Or is there perhaps another object that actually stores the Id references of the users that were tagged in a post? Somehow Salesforce manages to turn the @Mention tag into a link to the User, but I don't see that in the FeedItem object so I'm not sure where (or if) I can reference that data directly.

Is there a way to retrieve the user id of @mention user from chatter post in Apex? We can write a before insert trigger on feeditem, but when we display the body (which has @mention user) it simply displays as text. Is there any workaround for this?


Does Ubuntu Ubuntu 14.04.1 LTS have any OpenSSL vulnerabilities in connection with the Heartbleed bug? I downloaded the ISO today and I am installing it and I would like to know if there are any existing vulnerabilities.

I have read that there is a bug in SSL called heart bleed bug. Has Ubuntu 14.04 shipped along with this bug or has it been resolved in this release?


I have a friend who claims that you can leave the Schengen area for 1 night, and re-enter, to reset your 90 days.  For example, an Australian could enter Europe and then go for a couple of nights holiday to Morocco, Andorra, or London (any place outside of Schengen), and then return to Paris and have the passport stamped for another 90 days stay in Europe.  They swear by this and claim they know guys doing it for years.  My understanding, which admittedly is just from reading online and not real-world experience, was that we could only spend 90 days out of any 180 days in the Schengen region.    I've also heard other people say, no, you can't do that and if you are caught overstaying then you can be banned from re-entering schengen region for 5 years.  But, I've heard similar stories from several other people about leaving for 1 night making me think there is something to this story even if it's a loophole or a legal grey area (e.g. maybe the person checking at the border when you re-enter has to actually notice a previous stamp in your passport?)  So what are the real rules and facts about tourists staying in the Schengen region on these visa waiver agreements?

I have searched the web a lot and could not find an answer that fits my situation. Here are two links that are quite contradictory:       My situation:  I've visited Portugal in December 2012 for 29 days on a Schengen visa valid from December 1st, 2012 to February 1st, 2013 for research purposes (I am a Ph.D. student). I want to visit Sweden from February 10th, 2013 to May 10th, 2013 (89 days). I have applied for a Schengen visa again (for research). How will the 90/180 rule work in my situation?


I have been trying to show this proposition for hours, Does anybody have an idea how could i do it? This is the proposition:    This are the definitions and propositions more important:      I wait your help. Thanks

Suppose that a subset $S$ of $R^2$ has the property that locally on $S$ one of the coordinates is a $C^∞$ function of the other coordinate. Show that $S$ is a regular submanifold of $R^2$  My prof gave me a hint saying we must take charts $(U,x,y-f(x))$ and $(V,x,y-g(x))$ and show they are compatible and so are their adapted charts. What does he mean?  A subset $S$ of a manifold N of dimension $n$ is a regular sub- manifold of dimension k if for every p ∈ S there is a coordinate neighborhood $(U, φ ) = (U, x_1 , . . . , x_n )$ of p in the maximal atlas of N such that U ∩ S is defined by the vanishing of n − k of the coordinate functions. By renumbering the coordinates, we may assume that these n − k coordinate functions are $x_{k+1} , . . . , x_n$ .


My sister went to Chile in Sept'18, she was there for two weeks, left for Costa Rica, returned for two weeks, left for Ecuador then came back to Chile and has been there since.   I understand the tourist visa is 180 days from entering but we're not sure if that's from the first day she entered in Sept or the last time she went back in November. Either way, her tourist visa has now expired.  She applied for a 'temporary visa'? Something like that but hasn't heard back from them and is now looking to come home. Would she have to pay a fine for overstaying even though she applied for another visa in November and hasn't heard back or would she be free to leave without a penalty?

On 15 May, I entered Chile; my visa was for 3 months. On 10 July, I booked a ticket to go to New Zealand. I bought the ticket from LATAM Airlines for $1700 (USD).  But they didn’t let me board the flight to go to New Zealand and also they didn’t refund my money. Now, it is three months that I have been trying to get back my money, but they don’t want to give it to me unfortunately.  Now I want to leave Chile and go back to Amsterdam, my home. What should I do ?


I found this paragraph and I'm having trouble reading it, I understand that the total of all possible arrangments equal to A1*A2*A3...An but I don't understand how we get there from this:     If A1, A2...Ak are sets so that #Ai=ni>=1 for i=1...k, so cartesian product o A1 x A2 x ... x Ak, consisting of all vectors form (a1, a2...ak) with ai E Ai, has a total of n1*n2...nk elements, meaning:      (A1 x ... x Ak) = n1 * n2 ... nk

Definition of Multiplication principle in Principles and Techniques in combinatorics by Chuan-Chong, Khee-Meng is given as:      Let $$\prod_{i=1}^rA_i=A_1\times\dots\times A_r=\{(a_1,\dots,a_r) | a_i\in A_i, i=1,\dots,r\}$$ denote the cartesian product of the finite sets $A_1,\dots,A_r.$ Then $$\left\vert \prod_{i=1}^r A_i \right\vert=|A_1|\times\dots\times|A_r|.$$   I want to know how this principle is applies in defining $P_r^n=n(n-1)\cdots2\cdot1$, ie, what are sets $A_1,\dots,A_r$ here?


Anyone know of one? I noticed the question was asked once before , without any answers.  Also I saw that contributors of scikit-learn are working on a more scalable version of t-SNE in a comment .

My understanding of  and the Barnes-Hut approximation is that all data points are required so that all force interactions can be calculated at the same time and each point can be adjusted in the 2d (or lower dimensional) map.  Are there any versions of t-sne that can efficiently deal with streaming data? So if my observations are arriving one at a time, it will find the best location on the 2d map to place the new observation, or continuously update all points on the 2d map to account for ht new observation.  Would this even make sense or does it go against the setup of t-sne.


I have a cable texture and a simple curve. I want to map the texture on the curve so that it looks like a cable.   Note : I dont want to convert the curve to mesh and the map with uv. Reason is i dont want to make more verts and the file size heavy. Any suggestion. Thanks

I really want to be able to apply mapping to a curve object. For instance a rope or pipe that has a repeated pattern along its length that follows it's twists and turns.  There must be a simple way to generate UV coordinates for such an object without converting it to a mesh and unwrapping it. Can anyone help?


I found some combinatorial identities in my old notebooks, but I cannot recall how I derived them. Can anyone help provide the most elementary/elegant proofs for the following identity? Specifically, the connection between the summation and either of the two closed-form expressions. $$ \sum_{k=0}^n{ \binom{2k}{k} 2^{2n-2k} } = (2n+1) \binom{2n}{n} = \frac{n+1}{2} \binom{2(n+1)}{n+1} $$ Some specific cases written out for some simple visualization: ($n=0$ through $n=3$) $$ \begin{align} \binom{0}{0} 2^{0} &= 1\binom{0}{0} = \frac{1}{2}\binom{2}{1} \\ \binom{0}{0} 2^{2} + \binom{2}{1} 2^{0} &= 3\binom{2}{1}  = \frac{2}{2}\binom{4}{2} \\ \binom{0}{0} 2^{4} + \binom{2}{1} 2^{2} + \binom{4}{2} 2^{0} &= 5\binom{4}{2} = \frac{3}{2}\binom{6}{3}\\ \binom{0}{0} 2^{6} + \binom{2}{1} 2^{4} + \binom{4}{2} 2^{2} + \binom{6}{3} 2^{0} &= 7\binom{6}{3} = \frac{4}{2}\binom{8}{4} \end{align} $$ EDIT: I should specify that I have already found an inductive proof, but it is not satisfying to me. I am specifically looking for a bijective/double-counting proof ideally.

The identity I am interested in reads, $$ \sum_{k=0}^{n-1} {2k \choose k} \cdot 2^{2(n-k)} = 2n \cdot {2n \choose n}. $$ It is not hard to prove using the generating functions, but it seems that there should be a combinatorial argument. I tried different ideas with lattice path counting, but without success.   Update: I found a related discussion , however, among the many arguments there is no combinatorial one.  Update 2: it seems I have found a combinatorial proof (quite indirect), but will post it only after the bounty expires. I hope someone comes up with an answer before this so that the bounty is not wasted.


I have some template struct defined in templates.h:  //templates.h #ifndef TEMPLATES_H #define TEMPLATES_H  template<typename Key = int, typename Value = Key>  struct array{       map<const Key, Value> data;       //Stuffs  };  /*explicit (full) specialization*/  template<> template<typename Key> struct array<Key, char>{      map<const Key, Value> data;      //Stuffs };  #include "templates.cpp"  #endif   Trying to separate declarations (interface) from definitions (implementations), i did this in templates.cpp:  //templates.cpp #ifdef TEMPLATES_H #include "templates.h" #endif  template<typename Key, char>  array<Key, char>::array(const Key& k, const char* v){ cout << "specialised array<T, char>"; }    inside main(), i test-drove:  //inside main(); array<int, char> out(1, "Just testing");      /*error 1: prototype for 'array<Key, char>::array(const Key&, const char*)' does not match any in class 'array<Key, char>'                                                 error 2: candidate is: array<Key, char>::array(const array<Key, char>&)                                                     */   Question: I expected a call to array::array(Key, char) constructor; which is an explicit specialization of array::array(Key, Value), but got the error message commented above. what am i doing wrong, or how can i fix this ?.

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


What are the orbits of satellites; circular or elliptical?

Almost all of the orbits of planets and other celestial bodies are elliptical, not circular.   Is this due to  by other nearby massive bodies?  If this was the case a two body system should always have a circular orbit.  Is that true?


I want to know the meaning of static in my file. Everytime, I come across an error and then find out that the word static is missed. Can you please explain when and where should the word static be used.  Here, for example in the code, even if I remove static from the variable, it shows error.   Is, it static class, so it has to be static variable ??  public class TestJavaServer {      static String xCordinate;      public static void main(String[] args)     {                 readFromFile();         }     public static void readFromFile() throws IOException     {                        xCordinate ="something";        }

To be specific, I was trying this code:  package hello;  public class Hello {      Clock clock = new Clock();      public static void main(String args[]) {         clock.sayTime();     } }   But it gave the error      Cannot access non-static field in static method main   So I changed the declaration of clock to this:  static Clock clock = new Clock();   And it worked. What does it mean to put that keyword before the declaration? What exactly will it do and/or restrict in terms of what can be done to that object?


I received an email about some activity on a question, and noticed a small misspelling (chcecked instead of checked) in the email, screenshot below. The guys who I contacted via email said to post in meta, since here developers can track things related to main site (features, bugs, etc).

I just received an email from Stack Exchange <do-not-reply@stackexchange.com>, which has a misspelled word "chcecked". It should be "checked".     The following items were added to your Stack Exchange global inbox since you last chcecked it on   Screenshot:


I am wondering how can I prove $\lim\limits_{n \rightarrow \infty} {φ(n)=\infty}$   My attempt: For a prime number, we have φ(n)=n-1, so the equation above is proved. However, how can I prove it when n is a composite number?   What do you think about it? Could you please show me?  Regards

How can I show $\displaystyle\lim_{n\to\infty}\phi(n)=\infty$?  Obviously as $n$ approaches infinity it will have infinitely many prime factorizations, so the product series approaches infinity as well. How can I formally prove this?


On SO I was just editing an answer when I noticed this. In the preview the headline appears large & bold:  but in the published version it is just followed by an HR:  I was editing  if it matters.

With markdown, you can use some dashes for headings. For example, this: Hello ---- this is some other text  renders as this: Hello this is some other text This is fine and works well. When I want to quote that text is when the problem arises, since this Markdown: > Hello > ---- > this is some other text  When written down shows well in the preview but not when posted:  Hello this is some other text   As an example, see an screenshot of the preview:    and a screenshot of the posted content, where the ---- becomes a <hr>:  Note a similar bug I also reported: .


Ludwig was from Kaiserslautern, GE and said he was in the German Army. He was old enough for WWII, but not completely sure about when he served. He immigrated to USA in March 1957.

Where can I find information on German soldiers from World War I and World War II?   I am curious to find out about my ancestors' role in the wars, i.e. what rank they had, where they where fighting, with whom and anything else.


I am trying to create a dependent picklist in LWC and it is somehow not working. I have a controlling picklist called Event Types. The values for this picklist are fetched from a picklist field present on custom object Event. When a user changes the value in this picklist, in the onchange method, I am calling an Apex class which fetches the value for the dependent picklist. The values are getting returned as expected from Apex, then I am creating the array of objects for the dependent picklist, but the updated values are not getting displayed in the dependent picklist. Can anyone please let me know what's the problem with my code. Thanks.  <template> <lightning-layout class="slds-box slds-theme_default">     <lightning-layout-item size="4" padding="around-small" class="slds-box">         <template if:true={eventTypes.data}>             <lightning-combobox               name="eventType"               label="Choose Event Type"               value={selectedEventType}               placeholder="Select Event Type"               options={eventTypes.data.values}               onchange={handleEventTypeChange}             ></lightning-combobox>           </template>           <lightning-combobox               name="objects2"               label="Choose Object"               value={selectedObject}               placeholder="Choose Object"               options={objects}             ></lightning-combobox>     </lightning-layout-item> </lightning-layout>     JS Controller  import { LightningElement, wire, track } from "lwc"; import { getPicklistValues } from "lightning/uiObjectInfoApi"; import EVENT_TYPE_FIELD from "@salesforce/schema/Event__c.Event_Type__c"; import { getObjectInfo } from "lightning/uiObjectInfoApi"; import EVENT_OBJECT from "@salesforce/schema/Event__c"; import getSupportedObjects from "@salesforce/apex/PicklistController.getSupportedObjects";  export default class EventList extends LightningElement {   @track selectedEventType;   @track selectedObject;   @track objects = [];   @track error;    @wire(getObjectInfo, { objectApiName: EVENT_OBJECT })   objectInfo;    @wire(getPicklistValues, {     recordTypeId: "$objectInfo.data.defaultRecordTypeId",     fieldApiName: EVENT_TYPE_FIELD   })   eventTypes;    handleEventTypeChange(event) {     console.log("*****objects before push:", JSON.stringify(this.objects));     this.objects = [];     this.selectedEventType = event.detail.value;     getSupportedObjects({ eventType: this.selectedEventType })       .then(result => {         result.forEach(element =>           this.objects.push({             label: element.Object__c,             value: element.Object__c           })         );         console.log("*****objects after push:", JSON.stringify(this.objects));       })       .catch(error => {         this.error = error;       });   } }   The output of console log:  *****objects before push: [] *****objects after push: [{"label":"Account","value":"Account"}]  Apex Class:  public class PicklistController {      @AuraEnabled(cacheable=true)     public static List<Configuration__c> getSupportedObjects(String eventType){         return [SELECT Object__c FROM Configuration__c WHERE Event_Type__c=: eventType];     } }

We are migrating over to Lightning Web Components in the last couple of weeks now and we had some struggles with the arrays in Javascript. On a trackable array, when I call push in a wiredMethod, Array.push won't update the view. We found a workaround but I was wondering if there is a more elegant solution to this. Please take a look at the code snippets:  import { LightningElement, wire, track } from 'lwc'; import getData from '@salesforce/apex/LWCController.getData';  export default class myLWComponent extends LightningElement {     @track error;     @track dataArray = [];     @track processedArray = [];      @wire(getData)     wiredMethod({ error, data }) {         if (data) {             this.dataArray = data.arr;             this.dataArray.forEach(function (value) {                 // do some work on data here                 this.processedArray.push(value);             }         } else if (error) {             this.error = error;         }     }                  }   And on the view here:  <lightning-card title="Card Title">     <template for:each={processedArray} for:item='item'>         {item.title}     </template> </lightning-card>   Here is our workaround:  export default class myLWComponent extends LightningElement {     @track error;     @track dataArray = [];     @track processedArray = [];      @wire(getData)     wiredMethod({ error, data }) {         if (data) {             this.dataArray = data.arr;             let tempArray = [];             this.dataArray.forEach(function (value) {                 // do some work on data here                 this.tempArray.push(value);             }             this.processedArray = tempArray;         } else if (error) {             this.error = error;         }     }                  }   As you can see from the work around, if we set array to the temp array, framework understands that the array is updated and updates the view accordingly. We also tried setting values as follows which didn't work:  this.processedArray[index] = value;   We are wondering why push doesn't work and/or if there is a better way to do this.


I recently installed a browser extension to detect trackers on a webpage.   According to that extension, Stack Overflow uses two trackers:   Comscore Beacon Quantserve Tracker   While other Stack Exchange sites (I have checked MSE, History, SFF, Arqade and Politics) use just Comscore Beacon.  Why does Stack Overflow need two trackers? What kind of browsing activities do they track on SE sites?

I'm starting to block lots of javascript trackers using the  for reasons.  Currently Stack Exchange seems to be using the following tracking technologies across multiple sites according to my brief analysis:   Adzerk -  (and 4 other scripts once this parent script loads) Facebook Social Graph - several locations that seem machine generated as opposed to static links Google Analytics -  Quantcast -  ScoreCard Research Beacon -    Personally, I was stunned recently at how much more responsive the site was under marginal network connections with everything but gravatar blocked, but I also don't want to kneecap the site's revenue and research data. With broadband, I'm not seeing very measurable issues, but still am learning what/how these work in practice.   Would someone go out on a limb and rank these in terms of which ones are most critical to the site as currently designed?  I'm more tempted to unblock trackers when they are few and/or justified by the site owners with somewhat reasonable explanation on how they support the mission. It's clear my experience is better blocking these trackers, but I'm looking forward to learning the provider side of the story as well.  Thanks to anyone that can point me to where this is already documented or can answer below in a semi-official capacity.


I need to attach an event to a dynamically created element. With jQuery I can archive this by using the following code:  $("body").on("click", ".my-element", function() {});   And if I added a new .my-element, it automatically got the event attached.  I'm not creating the elements via document.createElement("div");, but I'm using  to reload just some parts of the page, so the main JavaScript file just loads one time, for that reason events need to be attached dynamically.  How can I achieve that with vanilla JavaScript?

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I love Stack Exchange and really hope to see it evolve, maybe into a helper page for sites like Wikipedia. One of the problems I have as a user is the kinds of questions I generally have are for lists of answers, or to get a vague and rambling set of answers to dig through and collect the pieces I'm looking for. For instance, it would be nice to ask for a list of great food websites (as an example only) and then get a listing of these sites.  I'm wondering if there is a sub-section or side-section of Stack Exchange that offers this kind of back-and-forth that is restricted on the Stack Exchange topics normally? I get that sites like facebook offer this to one degree or another, and message boards, etc. But none of those sites have the indexing, tagging, searchability, and referencing options that Stack Exchange does. So I'm hoping that there is a Stack Exchange-approved model for this question that I just wasn't aware of yet.

Stuff like polls, recommendations based on subjective constraints, puzzles, webcomics etc. do not belong on the serious main SE sites, where professionals should be considered at work and having just a few spare minutes ("code's compiling") to answer questions, so they should not be distracted by such things. However, I'd also like to have a home for these things still using the SE engine. For the reason I mentioned before, this needs to be a separate place though. Let's call it four.[sitename-here].com.


$$ |\mathrm e^{i\theta_1}-\mathrm e^{i\theta_2}|\le|\theta_1-\theta_2| $$  This seems like a simple inequality but I cannot prove it simply. Do I have to consider Taylor expansions? Could anyone help me how to prove this inequality?

I'm trying to prove the inequality  $$|e^{i\theta_1}-e^{i\theta_2}| \leq |\theta_1 - \theta_2|$$  I have tried to use Taylor's formula and got this  $$|e^{i\theta_1}-e^{i\theta_2}| = |(1+i\theta_1 - \frac{\theta_1^2}{2} + \ldots) -(1 +i\theta_2 - \frac{\theta_2^2}{2} + \ldots)| = |i(\theta_1-\theta_2) + \frac{\theta_2^2-\theta_1^2}{2}+\ldots|$$  The first term looks right, but how do I proceed?


Anyone have a walkthrough on installing Citrix receiver on Xubuntu 13.04 64-bit?    Update  $ sudo apt-get install libmotif4 nspluginwrapper   ... snip ...  Setting up libmotif4:amd64 (2.3.3-7ubuntu1) ...  Setting up nspluginviewer (1.4.4-0ubuntu5) ...  Setting up nspluginwrapper (1.4.4-0ubuntu5) ...  plugin dirs: nspluginwrapper: no appropriate viewer found for /usr/lib/flashplugin-installer/libflashplayer.so  Auto-update plugins from /usr/lib/mozilla/plugins  Looking for plugins in /usr/lib/mozilla/plugins  Segmentation fault (core dumped) Processing triggers for libc-bin ...  ldconfig deferred processing now taking place   sudo dpkg --install Downloads/icaclient_12.1.0_amd64.deb  Selecting previously unselected package icaclient.  (Reading database ... 155808 files and directories currently installed.)  Unpacking icaclient (from .../icaclient_12.1.0_amd64.deb) ...  dpkg: dependency problems prevent configuration of icaclient:  icaclient depends on libc6-i386 (>= 2.7-1);  however: Package libc6-i386 is not installed. icaclient depends on ia32-libs;  however: Package ia32-libs is not installed.  icaclient depends on lib32z1;  however: Package lib32z1 is not installed. icaclient depends on lib32asound2;  however: Package lib32asound2 is not installed. dpkg:  error processing icaclient (--install): dependency problems -  leaving unconfigured Errors were encountered while processing: icaclient

Has anyone managed to get the Citrix receiver client (icaclient) working in Ubuntu?


I know that the  was developed as an addition to the Einstein Field Equation as an anti-gravity force: $$R_{\mu \nu} - \frac{1}{2} R g_{\mu \nu} + \Lambda g_{\mu \nu} = \frac{8 \pi G}{c^4} T_{\mu \nu}$$  so that he could get a static universe. But later it was discarded. And now it is related to dark energy.  But what exactly does the cosmological constant mean. Is it a measure of the amount of dark energy? If so, how can we measure it? Please note that I want to know the physical meaning of the constant in our universe (but some mathematical exposure can be helpful anyway)  NOTE: The answer given here:  is more inclined towards the fact that the cosmological constant was developed as a tool to keep the universe static, or that it represents curvature where $T_{\mu \nu} = 0$, but what I am looking for is what do we think of the cosmological constant today? I am not asking how or why it crops up in the EFE, or why it was developed to make sense of a solution to the EFE, but simply what it really is, physically?

Newtons theory of gravity involves a gravitational constant $G$, however one does not refer to it directly, we speak instead of gravity or the force of gravity.   Now Einsteins introduced a  in his equation for GR, and ever since it's been referred to as such; however, this usage seems strange to me, given the above parallel; it seems to me we ought to be referring to something physical, which can then be quantified and whose quantification involves the cosmological constant.   Does the cosmological constant then refer to a cosmological force? A force that is, contra gravity, repulsive? And which is even weaker than gravity, kicking in on the scale of galaxies rather than solar systems?


Why we can overload -> and not . operator? Both are member access operator and has same significance.  I have read some reference from     AND    but still my doubts remains the same why we can overload .operator while not ->?   Is it because -> operator implicitly gets the reference of the returning pointer and thus making the call as the chain calls  struct X {     int foo; };  struct Y {     X x;     X* operator->() { return &x; } };  struct Z {     Y y;     Y& operator->() { return y; } };  Z z; z->foo = 42;          // Works!     z->foo = 42; This call is converted to ((z.operator()).opeartor()).operator() and thus value of foo is set to 42.  If I take this point I still have two more points,  1) why can't .(dot) operator works this way?  2) What if -> operator do not returns the reference to the class Y? Will it be a compilation error in that case?

It would be very useful to be able to overload the . operator in C++ and return a reference to an object.  You can overload operator-> and operator* but not operator.  Is there a technical reason for this?


I recently downloaded the  LaTeX template. When I build the PDF the below \textsc headers appear bunched up. Is there a line spacing parameter I could pass as an argument to \textsc? Also how do I post the output of the below code? Is that possible I believe I have seen it in other posts? I did try searching for an answer to my question! Please let me know If I need be more clearer and demonstrate my output.  %---------------------------------------------------------------------------------------- %   HEADING SECTIONS %----------------------------------------------------------------------------------------  \textsc{\LARGE Harvard University Extension School}\\[1.5cm] % Name of your university/college \textsc{\Large CSCI E-59 Database Design \& Implementation}\\[0.5cm] % Major heading such as course name \textsc{\large Database Design \& Implementation Final Project}\\[0.5cm] % Minor heading such as course title  %---------------------------------------------------------------------------------------- %   TITLE SECTION %----------------------------------------------------------------------------------------  \HRule \\[0.4cm] { \huge \bfseries The ACME Wholesaler Sales Order Database}\\[0.4cm] % Title of your document \HRule \\[1.5cm]

If I type something like this:  {\itshape\LARGE   Dunt venim dolorerosto do odit   ametum vulla conum dolore   conulput in vero od el   Dunt venim dolorerosto do odit   ametum vulla conum dolore   conulput in vero od el }   it results in a block of 4 lines with narrow spacing between the 1st and 2nd line and between the 3rd and 4th line. Line spacing between the 2nd and 3rd line is normal.  I can't fully explaing it to myself so I am looking for a short description for this behaviour. I know for example that with a \par at the end of the text (inside the group), the calculation would correct. But I have no idea why...


I have got this file downloaded:  ubuntu-12.04.4-desktop-amd64.iso   I have a 64 bit OS and want to install ubuntu 12.04 on it alongside win 7 (which I already ahve on the PC)  I have a Pendrive. how do I install ubuntu using the already downloaded file (given above) and a pendrive?

I am looking at this:    I need to create a boot disk to test Ubuntu to make sure it will run on a PC (Compaq Mini CQ10-120LA) I was given. I can create the boot disk off of a Mac (in English) or Windows (but Windows is in Spanish and foreign to me).   Questions:     What format do I choose for the USB stick? (I wish the instructions stated this). What is Dash? (Will I know when I run the installer?) Can I do this from a Mac or Windows computer? Or only from Ubuntu?


I'm fairly new to regular expressions and what I'm trying to achieve seems impossible after a few hours of trying. I could not find similar issues, so that is why I am making a separate question; please excuse me if there is already a question like that.  Now. I want to match every occurrence of the regular expression throughout the document; the occurrences are spanning multiple lines. Here is an example:  // javascript.js  /**  * #start?  * @name myFunction(p1)  * @desc Description of the function  * @param p1 : int = Parameter of type int  * ...  * #end?  */ function myFunction(p1) { ... }  /**  * #start?  * @name yourFunction()  * @desc Description of the function  * ...  * #end?  */ function yourFunction() { ... }   With the regular expression I would like to match the comment sections that describe the functions, from #start? to #end?. As a result I want to have 2 matched occurrences - the description of the first function and that of the second one.  What I came with is (#start\?)[\s\S]+(#end\?), but as you can guess it matches the first #start? and closes the match with the second #end?  How can I make it match all similar comment sections as separate occurrences?  Thank you very much for your time!  Update/Solution As pointed out by Wiktor Stribiżew - lazy != greedy The working regular expression for this case is (#start\?)[\s\S]+?(#end\?)

I have this gigantic ugly string: J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM J0000010: Project name: E:\foo.pf J0000011: Job name: MBiek Direct Mail Test J0000020: Document 1 - Completed successfully  I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time). Here's the regex I've been playing with: Project name:\s+(.*)\s+J[0-9]{7}:  The problem is that it doesn't stop until it hits the J0000020: at the end. How do I make the regex stop at the first occurrence of J[0-9]{7}?


I'd like to know if it's possible to link a .blend with another .blend file.  For example, I have a House .blend file, but it has no doors. I'd like to add multiple of the same door .blend file to the house, and have it so that if I edit the door .blend file, it will update all of the corresponding doors in the house .blend file, and possibly have it editable in the house .blend file too, where editing a door in the house .blend file would update all other door objects and the door .blend file.  I just find it would make life much easier for making models for things like games, where it's tedious to edit everything in 1 single file.  Thanks in advance!

I have created several designs for a particular project and they are related, but I don't want to have to keep recreating any similar elements, such as shared materials or textures.  How can I use the existing data in a new Blender file?


I read the following sentence and I was wondering if this is correct:   "Society and activist, non-governmental organizations monitor the sustainability performance of firms."  Or is "monitor  firms' sustainability performance" preferable, using the Saxon genitive?  Thank you!

I gave a quick answer to part of  which had not been covered by previous answers, trying to clarify the reason you would say time of decoding but not decoding’s time. I said it was ’s usually indicates possession, but of course there were several counterexamples that would have occurred to me after a moment’s consideration, and these where helpfully supplied:   Britain’s climate two days’ time  a day’s work  the sun’s rays   I am still of a mind to say that possession of some sort is what allows the ’s. Even though the sun does not have title to its rays, they do belong to the sun. Now, at the risk of duplicating the original question and/or being pigheaded, I am curious as to why time of decoding but not decoding’s time is correct, if not for the reason I gave.


I remember a short story or maybe novella about a first contact. The powers in place bring in a renowned linguist (female, iirc) and her team to help communicate with the aliens.  Working off the aliens' physiology, she works out their way of thinking and representing information. There was some visualisation involved, but they may actually have been studying "spoken" language.  In the end, communication was established and, iirc, the linguist started thinking in the alien patterns as well.  I seem to remember reading the story in Lightspeed magazine in recent years, but I can't find it. It may have appeared somewhere else.  Does anyone have better memory than me?

I read a story several years ago in which aliens come make first contact with Earth, and a bunch of scientists set to work trying to establish communication with them in various fields. The main character is a linguist and her team is working to try to figure out their written language, which doesn't have any sort of linear structure and can be read starting from any place.  It contains some explanation of quantum physics as an analogy for how they view time.  In the end, it turns out that the aliens don't perceive time in a linear fashion, and sort of see the future on equal terms with the past, etc. The main character learns to see time this way by studying their language, and the story is interspersed with her talking about what her child is going to do / is doing / has done.  I think I read it in a science fiction magazine but I'm not sure about this part.


was made community wiki in rev 14.  says:     [Post Made Community Wiki by being edited by more than 5 different editor]   (Side note "5 different editor" (instead of "...editors") is exact quote, that's just the way how system wrote it. Also worth noting that this happened before .)  The problem is, I found only three editors, not five: Jimmy edited , David edited  and all the rest seems to be done by yours truly. (For the sake of completeness, I found fourth editor but it was .)  In a simpler case I would say it's a  but here, I am not certain. Revision history  and I could have missed something.  Were there indeed five different editors when this post was made community wiki?

Surprisingly, I couldn't find a straight answer to this.  It's not entirely clear in the .  There are (at least?) four different types of edit actions:   Body edits Title edits Retags Rollbacks   And a few actions that show up in the history but aren't really "edits":   Close/Reopen Delete/Undelete   The FAQ seems to indicate that only body edits are important as far as "wikification" is concerned, but I'm not sure if that's really correct or if I'm just interpreting the post too literally.  The FAQ also says that rollbacks don't reverse the calculations - fine, but are they considered to be additional edits or are they ignored?  Can anyone tell me which of these actually count toward the wikification of a post, and whether the rules are any different for owner edits vs. multiple editors?


I have this code:    var userId = Int32.Parse(User.Identity.GetUserId());   using (var context = new IdentityContext())   {       roleId = context.Database.SqlQuery<int>("SELECT RoleId FROM AspNetUserRoles where UserId = " + userId).FirstOrDefault();   }   Is there a very quick and simple way I could time how long this takes to execute. Even if the answer is put into a variable after this code block that would be enough as I can debug and see how long it took.

I need to find a bottleneck and need to accurately as possible measure time.  Is the following code snippet the best way to measure the performance?  DateTime startTime = DateTime.Now;  // Some execution process  DateTime endTime = DateTime.Now; TimeSpan totalTimeTaken = endTime.Subtract(startTime);


On Lubuntu 18.04, Is /usr/lib/binfmt-support/run-detectors   supposed to choose mono or wine to run a windows or .net executable?  $ cat /proc/sys/fs/binfmt_misc/cli  enabled interpreter /usr/lib/binfmt-support/run-detectors flags:  offset 0 magic 4d5a  $ file /usr/lib/binfmt-support/run-detectors /usr/lib/binfmt-support/run-detectors: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=06509e829163c8e50781b5335883bf9a8ed47321, stripped   Why can't I run a Windows executable? How can I make run-detectors work?  $ ./PDFXCview.exe  run-detectors: unable to find an interpreter for ./PDFXCview.exe $ file ./PDFXCview.exe  ./PDFXCview.exe: PE32 executable (GUI) Intel 80386, for MS Windows  $ type wine wine is /usr/bin/wine   Thanks.

I uninstalled my wine, and installed a higher version of wine by compiling source.  However when I run an exe executable (whose path is in $PATH), it doesn't work as it used to:  $  PDFXCview.exe     run-detectors: unable to find an interpreter for /home/tim/program_files/document/pdfxchange_portable/PDFXCview.exe   I am not sure why I was able to run this executable directly before I uninstalled my old wine and installed the new one. How can I make $  PDFXCview.exe work now?  Note:  $ wine /home/tim/program_files/document/pdfxchange_portable/PDFXCview.exe   will work.   $ wine PDFXCview.exe   wine: cannot find L"C:\\windows\\system32\\PDFXCview.exe"   doesn't work. Note that the path of PDFXCview.exe is still in $PATH  Thanks.


I understand that by convention, the cross product is defined to be the vertical projection of vector $A$ on $B$ in the case of $A \times B$. But the vertical projection of $A$ on $B$ would still be in the same coordinate-plane as $A$ and $B$. Why should the resultant cross-product necessarily point in the orthogonal direction given by the right hand rule? We have always taken it for granted when solving problems, and my textbook does not make any attempt at an explanation.

I get the physical significance of vector addition & subtraction. But I don't understand what do dot & cross products mean?   More specifically,    Why is it that dot product of vectors $\vec{A}$ and $\vec{B}$ is defined as $AB\cos\theta$? Why is it that cross product of vectors $\vec{A}$ and $\vec{B}$ is defined as $AB\sin\theta$, times a unit vector determined from the right-hand rule?   To me, both these formulae seem to be arbitrarily defined (although, I know that it definitely wouldn't be the case).   If the cross product could be defined arbitrarily, why can't we define division of vectors? What's wrong with that? Why can't vectors be divided?


A question from Introduction to Analysis by Arthur Mattuck:  Suppose $f(x)$ is continuous for all $x$ and $f(a+b)=f(a)+f(b)$ for all $a$ and $b$. Prove that $f(x)=Cx$, where $C=f(1)$, as follows:  (a)prove, in order, that it is true when $x=n, {1\over n}$ and $m\over n$, where $m, n$ are integers, $n\ne 0$;  (b)use the continuity of $f$ to show it is true for all $x$.  I can show the statement is true when $x=n$. As for $x={1\over n},{m\over n}$, I don't know how.

The  asks about functions $f \colon \mathbb R \to \mathbb R$ such that $$f(x+y)=f(x)+f(y).$$ It is a very well-known functional equation, which appears in various areas of mathematics ranging from exercises in freshman classes to constructing useful counterexamples for some advanced questions. Solutions of this equation are often called . Also a few other equations related to this equation are often studied. (Equations which can be easily transformed to Cauchy functional equation or can be solved by using similar methods.) Is there some overview of basic facts about Cauchy equation and related functional equations - preferably available online?


I frequently use:  find /home -iname foo* 2> /dev/null   The 2> /dev/null suppresses any permissions issues and leaves legit matches.  I tried creating:  alias lost=find /home -iname ${1} 2> /dev/null

I want to know if I can pass an argument with an alias command.  for example:  alias d="dmesg|grep -iw usb|tail -5"    Now d will print the last 5 lines. If I want to use d to print a different number of lines, I have to make change in the alias command declaration of d again.  Is there any way I can modify the declaration of an alias so that I don't have to retype the declaration to change the number of lines. Like incorporating passing the number of lines as an argument while declaring alias for d? Or is there some other method to solve this?


link 1:   link 2:    I have found 2 solutions, the second one convinced me. But so far I cannot formally prove that the method given in the first link gives a reminder with its size function less then the size function of the divisor. And I think maybe there exist Gaussian integers $a+bi$, $c+di$, such that using the division algorithm in link 1 to divide $c+di$ by $a+bi$ gives a remainder whose size function value is greater than the size function value of $a+bi$.  Is it possible? If it is possible, could someone find such $a+bi$ and $c+di$?If the method in link 1 also allows us to always get a remainder with size function value less then the divisor, could someone formally prove that?  Thanks in advance!

I'm having some trouble proving that the Gaussian Integer's ring ($\mathbb{Z}[ i ]$) is an Euclidean domain. Here is what i've got so far.  To be a Euclidean domain means that there is a defined application (often called norm) that verifies this two conditions:   $\forall a, b \in \mathbb{Z}[i] \backslash {0} \hspace{2 mm} a \mid b \hspace{2 mm} \rightarrow N(a) \leq N (b)$ $\forall a, b \in \mathbb{Z}[i] \hspace{2 mm} b \neq 0 \rightarrow \exists c,r \in \mathbb{Z}[i] \hspace {2 mm}$ so that $\hspace{2 mm} a = bc + r \hspace{2 mm} \text{and} \hspace{2 mm} (r = 0 \hspace{2 mm} \text{or} \hspace{2 mm} r \neq 0 \hspace{2 mm} N(r) \lt N (b) )$   I have that the application meant to be the "norm" goes: $N(a +b i) = a^2 + b^2$, and I've managed to prove the first condition, given that N is a multiplicative function, but I can not find a way to prove the second condition.   I've search for a similar question but I have not found any so far, please redirect me if there's already a question about this and forgive me for my poor use of latex.


I'd find it useful if the number of items to review (say, the total number that your permissions allow) could display in the main menu bar next to the review link, similar to  how your reputation and number of badges show up net to your profile link.  The reason I ask is because it is a little annoying to keep checking, only to find that there are zero items to review.  But I do understand if the volatility makes it infeasible to keep it on every page (those posts that are there always go so quickly!).  I think I've seen this in the new top-bar - ?

I am under the impression that increased participation in the review queue is, on the whole a good thing.  It encourages people to feel an ownership in the community and partially responsible for the site as a whole.  On Programmers.SE, I've seen what I believe to be an uptick in flagging to close (non-audits with no votes in the close queue).  I believe that to be a good thing as it indicates to me that there are at least a few on P.SE who may some day become more active participants in the site.  On the other hand, I don't often see too many new names in the "recent reviews" page.  There are often new names scattered about on close votes of recent questions which suggests to me there is a population of 3+k users who don't review, but do close recent questions.  While the close queue at P.SE is completely different than the one at SO (we start wondering about it in chat when it hits 20 and occasionally motivate people to help smash the queue back to 0), I was wondering if there wasn't something that could be done to help direct everyone possible to review (or at least be aware of it - there was a comment at one point of a 10k user who wasn't aware of anything in the /review link after clicking it as a new user and not seeing anything in it that could be done by him).  The suggestion  Next to the review link display the number of reviews that user is capable of doing at this time, akin to the way the 10k banner looks when there are flags or edits outstanding.  Many people perceive numbers as "there is something here that needs my attention".  Inbox size, alerts on mobile device apps, notifications, etc...  Using this it would be possible to point people to the review part of the application and help them become a more active participant in the site and the community as a whole.  This number would be:  min(first post queue size, first post audits doable) + min(late answer queue size, late answer audits doable) + ...    There seems to be some confusion about what this would be and what the numbers on it would be.  I have used my considerable art skills (sorry, no pie) to make a mockup of what this would look like based on the current snapshot of what I see on P.SE    "Wait," you say... "why is that a 20?  Shouldn't it be 24?"  Nope.  Because on P.SE I can only do 20 close vote reviews a day (smaller queue or something of that nature).  If you hit it with someone who hasn't reviewed most of the queue, you'll actually see that its 60.  And still the answer should be 20.  And so, min(60,20) + min(0,20) + min(0,20) + min(0,20) + min(0,20) (those are the other queues there too) is 20.  And that's the number that should be shown.  This should be something that you can get to 0 every day.  Making it something that is an unmanageable number makes it something people will ignore, and that's not what this is suggesting.


Is there a way to set the new Nautilus in Ubuntu 13.04 to have an old behaviour I liked, namely:   Type something An item matching that name will be selected (pretty much like using the Tab key in a terminal)   This used to be virtually instant and quite convenient, but now it does a deep search across a variety of parameters when you start typing.   The deep search is useful, but by far the more frequent task is to select something within the current directory by name, which the old function satisfied perfectly.  Is there a way to restore this behaviour? I couldn't find an option in Preferences.  If possible, I'd like to avoid a roll-back as I hate to fight progress, but if that's the only option I'll take it.

Until now I was using a "traditional" version of Nautilus: that that comes with Ubuntu 10.10. Now I'm using 3.6.3, included with Ubuntu 13.04 (most likely any recent version is equivalent for the scope of my question, anyway).  One major difference between the two is the search-as-you-type behavior: in classic versions of Nautilus, when you typed an input, the file with the closest alphabetical match would become the selected one, the eligible files/folders being restricted to the current directory.  The new behavior is to perform an optionally-global search instead.  Can one configure Nautilus to provide the previous functionality ?


I've got the following exercise:Show that the series $\displaystyle\sum_{n=1}^{\infty}\dfrac{1}{\sqrt{n}+\sqrt{n+1}} $ converges and compute its limit if it's posible. I've already tried with the Integral test but is worthless, I've got the same thought about using the ratio test. So I don't know which one of the convergence test would be most useful to compute the limit.

Does the following series converge or diverge? $$ \sum\limits_{n=1}^\infty\frac{1}{\sqrt{n}+\sqrt{n+1}} $$ The methods I have at my disposal are geometric and harmonic series, comparison test, limit comparison test, and the ratio test.


can I process salad dressing for shelf life in a water bath or pressure canner and if I can how long is the process time, I can't find out anything about it please help.

I would like to bottle my homemade dressing. The main ingredients are olive oil, balsamic vinegar, honey, lemon and dijon mustard. Once it is bottled, is there a processing time as there is with canning vegetables?


Is there any way to create Task<T> in runtime where T is the type known only in runtime? I would like to create Task<T> with default value for T but after obtaining default value for T and use Task.FromResult(default_value)  I’m getting Task<object> instead of Task<T> because in most cases default value is null. Any Idea to fix this?  static void Main(string[] args)         {             var type = typeof(string); // fin real code type resolved in runtime             var default_value = GetDefaultValue(type);             var test = Task.FromResult(default_value); //Task<object> - how to get Task<T>         }          public static object GetDefaultValue(Type t)         {             if (t.IsValueType)             {                 return Activator.CreateInstance(t);             }             else             {                 return null;             }         }

Edit:  Of course my real code doesn't look exactly like this. I tried to write semi-pseudo code to make it more clear of whay I wanted to do.  Looks like it just messed things up instead.  So, what I actually would like to do is this:  Method<Interface1>(); Method<Interface2>(); Method<Interface3>(); ...   Well ... I thought that maybe I could turn it into a loop using reflection. So the question is: How how do I do it. I have very shallow knowledge of reflection. So code examples would be great.  The scenario looks like this:  public void Method<T>() where T : class {} public void AnotherMethod() {     Assembly assembly = Assembly.GetExecutingAssembly();      var interfaces = from i in assembly.GetTypes()     where i.Namespace == "MyNamespace.Interface" // only interfaces stored here     select i;      foreach(var i in interfaces)     {         Method<i>(); // Get compile error here!     }       Original post:  Hi!  I'm trying to loop through all interfaces in a namespace and send them as arguments to a generic method like this:  public void Method<T>() where T : class {} public void AnotherMethod() {     Assembly assembly = Assembly.GetExecutingAssembly();      var interfaces = from i in assembly.GetTypes()     where i.Namespace == "MyNamespace.Interface" // only interfaces stored here     select i;      foreach(var interface in interfaces)     {         Method<interface>(); // Get compile error here!     } }   The error I get is "Type name expected, but local variable name found". If I try  ...     foreach(var interface in interfaces)     {         Method<interface.MakeGenericType()>(); // Still get compile error here!     } }   I get "Cannot apply operator '<' to operands of type 'method group' and 'System.Type'" Any idea on how to get around this problem?


I'm trying to illustrate a classic physics problem where a rope that is coiled on the ground is lifted by one end until it is vertical; a quick online search turned up . Is it possible to create a similar sketch using tikz?

I feel intimidated in learning TikZ. I was wondering if there are some nice materials (or just your replies) at different level:   for providing big picture, which is important to beginners to not lose direction during learning. for comprehensive reference.   Examples are important, but only examples are not always clear for understanding the big picture and organization.


So I just ran into this issue, and while i've been working Javascript a while now, I didn't realize what seems to be an innate behavior and I'm hoping you guys can help explain when in this is the case. Consider this:  let a = {key1: [1,2,3]}; let b = a.key1; b.pop(1); console.log(a); // { key1: [ 1, 2 ] }   It appears that instead of b becoming a copy of a.key1 it is infact passing a pointer to the original data. This causes any changes that I make to b reflect up to a.key1. So my question is where can I read more about this behavior, does this apply for copying solely objects, or does it apply to other things (e.g.arrays, strings).  This is somewhat alarming to me considering code I've written in the past not being aware of this and leaving landmines for myself to find later...

The primitive types (number, string, etc.) are passed by value, but objects are unknown, because they can be both passed-by-value (in case we consider that a variable holding an object is in fact a reference to the object) and passed-by-reference (when we consider that the variable to the object holds the object itself).  Although it doesn't really matter at the end, I want to know what is the correct way to present the arguments passing conventions. Is there an excerpt from JavaScript specification, which defines what should be the semantics regarding this?


While modifying a node script I inadvertently created a directory with files in it called "Test..".  I have tried deleting it from explorer and it just tells me:     Could not find this item   This is no longer located in c:\myparentfolder. Verify the item's location and try again.   But the directory is still there. Couriously if I create another directory called "Test" and then delete "Test.." from explorer, it will delete "Test" and leave "Test..".  I have also tried rmdir /s /q "Test.." but it just tells me that      The system cannot find the file specified.   How can I remove this folder?

I'm trying to delete a folder in Windows 7 and get a perplexing error message: "Could not find this item:  This is no longer located in G:\Graphics.  Verify the item's location and try again.  I can see the folder -- I can find it.  I just can't delete it.    I also get a second error message (sometimes) when I click on the folder: G:\Graphics 2009-11-17 refers to a location that is unavailable...this information might have been moved to a different location.    I'm using Windows 7; this folder is on an external hard drive.  I've emptied the folder (there were items in it); I've scanned that external hard drive for errors.  Trying to rename the folder yields the same enigmatic error message.    Is there a way to delete this folder?


I really need to know the answer to the second question from the Squirrel.  "That's right! Here's 20 candies for you. Now complete this sequence of letters and you'll get a new reward : S, E, I, D,          N, A, ?"

I'm at the part where I am asked to complete a sequence of 7 letters and a question mark. I simply just don't understand what I am supposed to do. Can I get some help?


My code looks somewhat like this:  <form method="POST"> //something <form method='GET'> <input readonly type='text' id='userpwd' value= 'Day'  name='count'/> <input type='submit' id='btn' formaction='admi.php'  name='admin' value='Add Details'></form> <input type="submit" id="btn" formaction="choose.php"  name="admin" value="Done"></p> </form>   I want to get the value of readonly type input in my new php file.How could I achieve this.I tried doing this:  $var=$_GET['count'];   but it is giving following  error msg:  Notice: Undefined index: count in C:\xampp\htdocs\tourism\admi.php on line 4   Please somebody help me out..!Kindly give some solution in php only.

Is it possible to nest html forms like this  <form name="mainForm">   <form name="subForm">   </form> </form>   so that both forms work? My friend is having problems with this, a part of the subForm works, while another part of it does not.


I've already created a design for an iOS application using Adobe Illustrator default font (Myriad Pro). Can I use this font in development too? (Create an app as a product). As far as I searched, I think that I can not use it because there is no license for that. In this case, are there any alternatives that can be used instead of Myriad Pro ?

Are there any fonts that I can use in my font stack that are more or less similar to  and ?


When writing software documentation I very often have to describe things like a value manager, a value cache or a device map. These are usually components of the software system. In practice the manager does of course not manage a single value but many and the map does not map only a single device etc. My question is: is it more common to speak of a values manager instead of a value manager and of a devices map instead of a device map etc.?

Sorry for the title, it is not very evident and intuitive but I really do not how to tell it better...  Well, you know, several times, or better, many times, we use this form:  If I want to say:      "development of special weapons was   the first point in Hitler's   program..."   I will say this (a better form):      "special weapon development was..."   OK...  is it      "special weapon development"   or      "special weapons development" (note   the plural...)   what's the grammar rule in order to understand how to use this very used form?


Let $G$ be a graph with n vertices. Prove that $\chi(G)\cdot\chi(\overline G)\geqslant n$.   I know that the chromatic number of a graph with $n$ vertices will have somewhere between $\chi(G-\ni) \leqslant\chi(G)\leqslant\ni(G-v)+1$ and also that the upperbound of the chromatic number will be greater than or equal tot he max degree of a vertex in $G+1$ and that the lower bound is the greater than or equal to the largest clique.  Is there anything we can do with this information to prove our proposition?

Is there any relation between the chromatic number of a graph $G$ and its complement $G'$ that are always true?  I saw these ones: $\chi(G)\chi(G')\geq n$ and $\chi(G)+\chi(G')\geq 2n$,  but I'm not pretty sure about them.


I've composed a few queries and then I found that there is not an option to remove some of those.  I  but no luck.    Is there a way to delete some of my own queries?

As the title says. There's a history of all our queries and it would be good to be able to delete the lousy queries and keep the useful ones.   Is there a way to do this?


I am having trouble understand theorem $9.4$ of Chapter $6$ of Lang's Algebra (pg. 300-301).   The setup is a we have a field $k$ of characteristic not dividing $n$. We know that the splitting field of $f=X^n-a$ is $k(\zeta_n,\alpha)$ where $\alpha$ is a root of $f$ and $\zeta$ a primitive $n^{th}$ root of unity. Any automorphism $\sigma$ of the Galois group of $f$ over $k$ maps $\alpha \mapsto \alpha\zeta^b$ where $b$ is unique modulo $n$, and $\sigma$ induces an automorphism of the cyclic group $\mathbf{\mu_n}=\left\langle \zeta \right \rangle $ via $\zeta \mapsto \zeta^d$ where $(d,n)=1$ and $d$ is uniquely determined by $\sigma$.   We then verify that the map  $\sigma \mapsto \begin{pmatrix} \ \ 1 & 0\\ b_\sigma & d_\sigma \end{pmatrix}$ where $b$, $d$ are the integers determined by $\sigma$ in the previous paragraph is an injective homomorphism into the group $G(n)$ of all matrices $\begin{pmatrix} \ 1 & 0\\ a & c \end{pmatrix}$ such that $a \in \mathbf{Z}/n\mathbf{Z}$, $c \in (\mathbf{Z}/n\mathbf{Z})^{*}.$    The question that the theorem addresses is when the above the map is an isomorphism of the Galois group of $f$ and $G(n)$. With $\phi$ being the Euler function, the theorem states:   Suppose $[k(\zeta_n):k]=\phi(n)$ and let $a \in k$. Suppose for each prime $p|n$ that $a$ is not a $p^{th}$ power. Let $K$ be the splitting field of $X^n-a$ over $k$ and $G$ the Galois group. Then the above map is an isomorphism $G \cong G(n)$ with commutator subgroup Gal$(K/k(\zeta_n))$, so $k(\zeta_n)$ is the maximal abelian subextension of $K$.   The proof begins with the case $n=p$ where $p$ is a prime, which I follow. However, following that case Lang writes (bold is what I don't understand):  A direct computation of commutator of elements in $G(n)$ for arbitrary n shows that the commutator subgroup $C$ is contained in the group of matrices $ \begin{pmatrix} \ \ 1 & 0\\  b & 1 \end{pmatrix}$, $b \in \mathbf{Z}/n\mathbf{Z}$ and so must be that subgroup because its factor group is isomorphic to $(\mathbf{Z}/n\mathbf{Z})^{*}$ under the projection on the diagonal.  When $n=p$ is prime I already happened to know that $G \cong \mathbf{Z}/p\mathbf{Z} \rtimes_\varphi (\mathbf{Z}/p\mathbf{Z})^{*}$ from which it is clear (I think?) that the quotient by the image of $\mathbf{Z}/p\mathbf{Z}$ is the maximal abelian quotient, and the fact that the commutator subgroup is nontrivial inside a subgroup of order $p$ means it must be the whole group. However, when $n$ is arbitrary it's not obvious to me why the quotient by the commutator $C$ in $G(n)$ is ismorphic to $(\mathbf{Z}/n\mathbf{Z})^{*}$ nor why $C$ has to be isomorphic to $\mathbf{Z}/n\mathbf{Z}$. If someone could explain what is missing here that would be much appreciated.  I also have a couple of questions on the rest of the argument which I will just link here     1.) On the $3^{rd}-4^{th}$ lines: $\beta$ is a root of $X^m-a$ and by induction we can apply the theorem to $g=X^m-a$.   OK, fine, but what is Lang using the induction for? The splitting field for $g$ is $k(\beta,\zeta_m)$ and has Galois group isomorphic to $G(m)$ and it's maximal abelian extension is $k(\zeta_m)$. I've been staring at this and I don't see what the conclusion is.  2.) lines $3-5$ after the diagram: apply the $1^{st}$ part of proof (case of $n=p$ is prime) to $X^p-\beta$ over $k(\beta)$...shows that $k(\beta,\zeta_n)\cap k(\alpha)=k(\beta)$.  Again I don't know what exactly is being said. The splitting field of $X^p-\beta$ over $k(\beta)$ is $k(\alpha,\zeta_p)$, and it's maximal abelian subextension is $k(\beta,\zeta_p)$. How does Lang's conclusion follow from that?   Thanks to everyone who took the time to read my question, any help is much appreciated.

In Section 9 of Chapter 6, Lang constructrs for the first time a non-abelian extension as a splitting field $K$ of $X^n - a$ when the ground field $k$ does not contain primitive $n$-th roots of unity $\zeta_n$. He constructs an injective homomorphism of the Galois group $G(K/k)$ into the matrices of type   $$ M=\begin{pmatrix} 1 & 0 \\ b & d \end{pmatrix} \quad \hbox{with}\ b\in \mathbb{Z}/n\mathbb{Z} \quad \hbox{and} \quad d\in (\mathbb{Z}/n\mathbb{Z})^*,$$  where $(\mathbb{Z}/n\mathbb{Z})^*$ the multiplicative group of integers modulo n.  Afterwards, he states in Theorem 9.4 that if $n$ is an odd positive integer prime to the characterstic and $[k(\zeta_n):k]=\varphi(n)$ (i.e, the primitive roots of unity are not in the ground field), then the above homomorphism is, in fact, an isomorphism. Besides, the commutator group is $G(K/k(\zeta_n))$, so $k(\zeta_n)$ is the maximal abelian subextension of $K$.  Lang proves the theorem inductively over the number of prime factors in the decomposition of $n$ (i.e. if $n=9= 3\cdot 3$, then the proof "would take two steps" to complete). The induction start with $n$ prime is written clearly and I agree with it.   Now come the questions:   I do not understand Lang's argument to prove that the commutator subgroup is the subgroup $\begin{pmatrix}1 & 0 \\ b & 1\end{pmatrix}$, $b\in \mathbb{Z}/n\mathbb{Z}$. What is this projection on the diagonal and how does one see that the factor group of the commutator group is isomorphic to $(\mathbb{Z}/n\mathbb{Z})^*$?   By the way, direct computation of $x\, y\, x^{-1}\, y^{-1}$ for two arbitrary matrices $x=\begin{pmatrix} 1 & 0 \\ b & d \end{pmatrix}$, $y=\begin{pmatrix} 1 & 0 \\ c & e \end{pmatrix}$ yields a matrix $\begin{pmatrix} 1 & 0 \\ b(1-e)+c(d-1) & 1 \end{pmatrix}$. As $n$ is odd, $2 \in (\mathbb{Z}/n\mathbb{Z})^*$, so taking $e=1$ and $d=2$, we indeed reconstruct the above-mentioned group.   The second (inductive) part of the proof is a complete mystery to me with virtually every sentence being a Theorem which needs an extra proof. Can someone give me some hints?   2.a. Lang writes $n=p\,m$ and takes $\alpha$ to be the root of $X^n-a$. It is clear that $\beta=\alpha^p$ is a root of $X^m -a$. Now comes the argument "By induction we can apply the theorem to $X^m-a$". I agree that we can apply it here but the result is that $K=k(\beta,\zeta_m)$ is the splitting field of $X^m-a$. In the diagram below, there appears $k(\beta,\zeta_n)$ out of nowhere.   2.b. Now Lang proceeds to apply the theorem on $X^p-\beta$ over $k(\beta)$. Bergman's "Companion" reminds to check that $[k(\beta,\zeta_p):k(\beta)]=\varphi(p)$ before applying the theorem and gives a hint "$[k(\zeta_p):k]$ and $[k(\beta):k]$ are relatively prime". I disagree with this hint. Take $n=21= m p$ where $m=3$ and $p=7$. Then $[k(\zeta_p):k]=\varphi(p)=p-1=6$ but $[k(\beta):k]=m=3$ and both are not co-prime. Can we apply the theorem here at all? Or if so what is the argument? If Bergman's argument is valid, where is the fault in my logic?  2.c. Even assuming that we can apply the theorem in 2.b., then we can say something about $k(\alpha, \zeta_p)$ and not $k(\alpha,\zeta_n)$. How do we proceed to checking everything Lang states in the last section of the proof (basically, everything after the diagram)?  EDIT: I have found the essentially same question


If I understand correctly, particle is something at a point of time, where you can tell it's position, but what if particle is moving, then you can tell it's speed.  From what I understand wave is NOT particle moving, but rather, a phase the particle is in. The particle was agitated and turned into a wave.  So, what do you call a moving particle if it's not a wave? Could the particle's movement be represented as a wave because particle has tendencies to be at certain places at certain times?

I often hear about the wave-particle duality, and how particles exhibit properties of both particles and waves. However, I wonder, is this actually a duality? At the most fundamental level, we 'know' that everything is made up out of particles, whether those are photons, electrons, or maybe even strings. That light for example, also shows wave-like properties, why does that even matter? Don't we know that everything is made up of particles? In other words, wasn't Young wrong and Newton right, instead of them both being right?


I was messing around with some try...catch...finally executions and noticed a breakpoint in finally won't seem to be hit:      try {         System.out.println("in try");         int num = 5 / 0;     } catch (ArithmeticException e) {         System.out.println("in catch");     } finally {         System.out.println(); //breakpoint here         System.out.println("in finally");     }   The breakpoint in the finally doesn't seem to hit, however it prints out successfully.  However, if I change the try to int num = 5 / 1;, and therefore not going in to the catch, the breakpoint is hit.  I'm using Netbeans 8.1.  Is there a reason for this?

Considering this code, can I be absolutely sure that the finally block always executes, no matter what something() is?  try {       something();       return success;   }   catch (Exception e) {        return failure;   }   finally {       System.out.println("I don't know if this will get printed out"); }


I like to include an image with   \includegraphics[width=5cm]{./images/My_Image.svg.png}   where the image is an png file that had been converted with inkscape from an svg and therefor the filename-ending is .svg.png on linux.   Now pdflatex does not recognize it as an png  ! LaTeX Error: Unknown graphics extension: .svg.png.   What can I do, besides renameming the file?  Renaming does not work, because the files are needed in exacly that name from somewhere else, my last idea would be to use symlinks, but I would prefer a "latex-only" solution

\includegraphics cannot handle filenames that contain more than the one dot, separating the filename from the extension. Apparently it uses everything after the first dot as extension and then, of course, complains about an unknown graphics extension.  This is annoying as I very often have filenames that contain parameter values, e.g. plot_a0.4_b0.6.pdf.  Is there a way to teach LaTeX to interpret only the string behind the last dot as extension?


I have a 32 gb usb and i am using windows as my daily driver. in my home there are 2laptops and 0 desptops one of them died which is my daily driver and i use linux on it and the windows one is my dads so i cant do dual boot as it got only 500 gig storage so i want to install ubuntu 20.04 on my usb to daily driver it . I am a linux user and fan but i am just learning about it .  Note Please dont tell the rufus or other program for persistant boot because it wont work very god with me i tried that.  If i can install ubuntu on usb just like hardisk install so please tell me i got to know that ubntu's community is very good so please tell me this is my first question

I am using Windows 10, and hasn't got not enough SSD storage. So, I decide to install Ubuntu in a 32 GB USB stick (made by tf card and reader ).  I will not just try Ubuntu, but will use it everyday, and will install Python, VS Code, PyCharm, etc... Hope to learn coding with this USB stick. Will it work perfectly?


I'm having an issue that is probably more easy than I am making it out to be. (I am in an intro level programming class)  Basically I am writing a program where I ask a user for a file name, I read info from the file before sorting it in a list and writing it somewhere else. The assignment wants us to ask user for the file name to read from. If the user enters the file name with the '.txt', we carry on with the processing. If they do not, we must add the '.txt' before continuing on. I know how to add the '.txt' to the file name if they did not include it, but I can not figure out how to check first to see if they did.  How do I go about first checking to see if the user wrote the file name with the extension?  I am assuming it has something to do with an if/else statement but I have been baffled.  Thank you

Is there a function to extract the extension from a filename?


Yesterday, I briefly discovered that holding the click on my Chrome's reload button opened a dropdown. It had:    reload (ctrl+r)  hard reload (shift ctrl +r)   clear cache and reload   .  A few seconds later my office mate said his Chrome needed updating and checking mine I saw that it did too.   Unfortunately, after updating the awesome extended multi-function features of the reload button are no longer there.  Has anyone else discovered the multi-function relaod button or still have it or know how to get it back? And it wasn't an extension or a plug-in, none of those changed or were updated.  Any help clearing up my mystery is appreciated.

I don't know what exactly it's called, by cache refresh I mean, refresh the page after clearing its cache. I don't want to clear the entire browser cache.  I can't seem to cache refresh my pages. In Firefox, I know it to be Shift+Refresh.  In Chrome, I've tried Ctrl+R, Ctrl+Refresh, Alt+Refresh, Shift+Refresh but none of them work.


Here is a javascript dropdown menu. I got it from some site it works fine but problem is the dropdown menu closes only when menu button is clicked. How can I make dropdown menu close even when I click any where else on page.
 <button onclick="myFunction()" class="dropbtn">ddm</button>

I have some HTML menus, which I show completely when a user clicks on the head of these menus. I would like to hide these elements when the user clicks outside the menus' area.  Is something like this possible with jQuery?  $("#menuscontainer").clickOutsideThisElement(function() {     // Hide the menus });


I have fallen into a slump at the minute where i just don't feel like preparing food when i get home from work, and i would prefer to cut up a larger batch of potatoes in one go and store them in the fridge/freezer in the correct portion sizes, so when i get home i can just throw them into the oven.  The problem i have had with this up to now is, if i put them into the freezer and then try to cook them, the defrosting process turns them to mush. If i put them in the fridge, they have gone off by morning.  Is there a better way to store potatoes that have been cut up?


I like how canning bone broth causes the broth to go clear. My recipe for bone broth is to cover bones with water and simmer on low for 4-5 hours.   I then strain it several times with the last straining through cheesecloth.  The broth is milky in appearance at this stage. The left-hand jar was made at the same time as the right hand jar.   I just didn't have room in the canner to do all the jars in 1 batch, so it went in the fridge instead.  After the left-hand was canned, the broth turned clear as well. Is there a way to get clear bone broth without pressure canning it?  Taste wise, both jars are the same but I find the broth in the right hand jar substantially more appetizing than the left hand jar. I should point out that when the picture was taken, the broth in both jars was jelled.  They retain the state of milkiness or clarity when heated though.

I often like to cook an entire chicken in water in a crockpot. After the chicken is done cooking, I remove all the meat and then throw the bones & organs back in, pour some extra water in, and let it sit for a day on "Keep Warm".  Now the only thing is that I find that there's some brown particles floating around that I'd rather not be in there. I do my best to clean out the chicken before putting it in, but I'm still not entirely trusting.  Anyway, how can I filter this stuff out to just leave me with a liquid broth?


Define the exponent of a group as $\sup o(a)$ ,where $a \in G$. Show that if $G$ is a finite abelian group $o(a)$ divides the exponent of $G$, for each $𝑎\in 𝐺$ Here $o(a)$ denotes the order of an element $a$? How can I show this? Can someone please show the right approach to attempt this question. Thanks.

Let $a$ be an element of maximum order from a finite Abelian group $G$. Prove that for any element $b$, $|b|$ divides $|a|$ (order of $b$ divides order of $a$).


I have data of customers and their numbers. I want to show it in dataTable. Additionally, I am trying to color those rows whose numbers are invalid and also disable the checkbox for that row. I have stored 'invalid-number' in the column:'valid' of the Customer objects for those records. First, I have tried to hide checkbox for those records by writing following code:  <lightning:datatable data="{! v.CustomerList }" class="slds-m-top_medium"     columns="{! v.columns }"      keyField="id"     hideCheckboxColumn="{!valid == 'invalid-number'}"     onrowselection="{! c.getSelectedName }"/>      But this code is not working for me and also I need pointers for coloring these rows with invalid numbers.

Canonical Question  I want to do <some really cool thing> with a lightning:datatable, but I can't seem to figure out how to do it. I checked the , but I did not see a way to implement <this really cool feature I need>.  Perhaps I want to provide tooltips, or a pick list, or alter the behavior of the menus, or display images, or show a custom component I created, or define a new row-level click behavior, or alter the keyboard event handlers, etc.  Can I somehow do this?


I want to declare an unsigned long long array with 2mil. elements. When I first define the length of the array const and then define the array I get a segmentation fault error. However when I define the length just as unsigned long long the declaration works.   int main(int argc, const char *argv[]) {     const unsigned long long lim = 2000000; //If I omit const, it works.     unsigned long long nums2lim[lim];      exit(EXIT_SUCCESS); }   Does anybody know why the segmentation fault is thrown?

The following code is generating a stack overflow error for me  int main(int argc, char* argv[]) {     int sieve[2000000];     return 0; }   How do I get around this? I am using Turbo C++ but would like to keep my code in C  EDIT:  Thanks for the advice.  The code above was only for example, I actually declare the array in a function and not in sub main.  Also, I needed the array to be initialized to zeros, so when I googled malloc, I discovered that calloc was perfect for my purposes.  Malloc/calloc also has the advantage over allocating on the stack of allowing me to declare the size using a variable.


Why are second order partial differential equations able to model such a wide variety of physical phenomena? Why do we never need to go to third or fourth order ?It seems just about everything can be described with such equations, as if physical reality is just second order in nature. Is there a reason for this?

What is the reason for the observation that across the board fields in physics are generally governed by second order (partial) differential equations?    If someone on the street would flat out ask me that question, then I'd probably mumble something about physicists wanting to be able to use the Lagrangian approach. And to allow a positive rotation and translation invariant energy term, which allows for local propagation, you need something like $-\phi\Delta\phi$.  I assume the answer goes in this direction, but I can't really justify why more complex terms in the Lagrangian are not allowed or why higher orders are a physical problem. Even if these require more initial data, I don't see the a priori problem.  Furthermore you could come up with quantities in the spirit of $F\wedge F$ and $F \wedge *F$ and okay yes... maybe any made up scalar just doesn't describe physics or misses valuable symmetries. On there other hand in the whole renormalization business, they seem to be allowed to use lots and lots of terms in their Lagrangians. And if I understand correctly, supersymmetry theory is basically a method of introducing new Lagrangian densities too.   Do we know the limit for making up these objects? What is the fundamental justification for order two?


I put an 8pound Boston butt in the crock pot last night to cook. Crock pot got hot I went to bed. Sometime during the night the crock pot turned off. Everything was cold. Is it safe to cook and eat?

If I left food out of the refrigerator for some period of time, is it still safe? If I left it out too long, can I salvage it by cooking it more?


Let $G$ be a group, and $N \lhd G$ so that $[G:N]=2014$. I need to prove that there is a subgroup of index 2.  Indeed, since $N \lhd G$, $o(G/N)=2014$, but I  couldn't find how to go on.

Let $n$ be a positive integer. Show that any group of order $4n + 2$ has a subgroup of index 2. (Hint: Use left regular representation and Cauchy's Theorem to get an odd permutation.)  I can easily observe that $\vert G \vert = 2(2n + 1)$ so $2 \mid \vert G \vert$ and 2 is prime. We have satisfied the hypothesis of Cauchy's Theorem so we can say $G$ contains an element of order 2.  This is where I am stuck  I am confused about how the left regular representation relates to the group. So my understanding at this point is that every group is isomorphic to a subgroup of some symmetric group. My question: is the left regular representation $\varphi : G \to S_G$ an isomorphism? where $G \cong S_G$ or is $S_G$ the same thing as $S_{\vert G \vert}$ and $\varphi$ is only an injection? I'm using Dummit and Foote for definitions.  I saw an argument online that said that since we have an element of order 2, there is a $\sigma \in S_G$ of order 2, but it is a product of $2n + 1$ disjoint 2-cycles. I don't understand how they could claim this and tried working it out on my own but didn't get there. -- They then went on to use the parity mapping $\varepsilon : S_G \to \{\pm1\}$ and since we have an odd permutation $\sigma$, we have $[S_G:\text{ker }\varepsilon] = 2$. I understood their computation but not how that directly shows that $G$ has a subgroup of order 2? unless $G \cong S_G$ because of how left regular representation is defined. (but again, I'm not understanding that concept very well yet.)  So, to be clear about my questions:   What is meant by left regular representation, is it an isomorphism or just an injection? and how would it be used here. If it is an isomorphism, the argument online starts to make more sense, but how can they say that since $\sigma$ is even, it is made up of $2n + 1$ disjoint transpositions? If you have a full, proof, I'd appreciate it, but good hints are just as good!   Thanks you!


I need to show 7 posts of a certain category.  The first needs to appear as Title / Date / Excerpt.  While the others can just be Titles of the posts.  Right now I am having trouble with getting the first post to appear different with my specific code.  Any help would be appreciated, thanks.  <?php $the_query = new WP_Query( 'showposts=7&cat=113' ); ?> <?php while ($the_query -> have_posts()) : $the_query -> the_post(); ?> <a href="<?php the_permalink() ?>"><?php the_title(); ?>
 <?php endwhile;?>

Hi i'm using the code below to call post from a certain Category under certain post types, But how do i style it so that i can make the first post different from the rest of the post.  <?php $queryObject = new  Wp_Query( array(         'showposts' => 4,         'post_type' => array('pretty-little-liars', 'revenge', 'once-upon-a-time'),         'category_name' => celebrity,             'orderby' => 1,         )); // The Loop! if ($queryObject->have_posts()) { ?>  <?php while ($queryObject->have_posts()){     $queryObject->the_post();     ?>  <a href="<?php the_permalink(); ?>" title="<?php printf(__( 'Read %s', 'wpbx' ), wp_specialchars(get_the_title(), 1)) ?>">                     <?php the_post_thumbnail('video-post'); ?>                       <?php echo human_time_diff( get_the_time('U'), current_time('timestamp') ) . ' ago'; ?>                 <a href="<?php the_permalink(); ?>"><?php the_title(); ?>   <?php } ?> <?php wp_reset_postdata(); } ?>


Say I want to see whether two variables y and x1 are linearly related, while controlling for the effect of an x2 "nuisace" variable. What is the difference between  (a) regressing y over x1 and x2 and just looking at x1's coefficient; and  (b) doing a partial correlation for y and x1 while controlling for (co-varying) x2?

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


I remember a book about a man who could smell emotion, and lived in a labyrinth filled with traps.  A team goes into the labyrinth either to get him, or for archeological reasons, and have to contend with the multitude of traps.  I think it may have been called Labyrinth, but without an author, I've no hope of finding this one.

I am trying to identify a fix-up novel, where I think I only remember a sub-story from the middle.  It was probably published at least fifteen years ago, but I cannot pin down the date better than that.  The main character volunteers to travel to an alien world (maybe with the first intelligent aliens humans have identified?).  A remote probe had sent back some visual data on the aliens, before the aliens destroyed the probe.  The main character has some history as an amazing explorer or risk-taker, and he is sent to try to establish communication with the aliens.  His chance of coming back alive is rated as being very low.  I don't think it's clear what happens to him on the aliens' planet.  Maybe he doesn't remember it, or he thinks that his mission was a failure, and he eventually decides to return to Earth.  However, upon his return, it turns out that the aliens have modified him, in an attempt to enable communication.  He has become an overpowering telepathic projector; every thought and emotion in his mind is communicated to everyone near him.  This is extremely unpleasant at close range.  (I think there's a scene where his girlfriend is really, really trying to have sex with him after he comes back, but she is ultimately unable to.)  Eventually, he decides that he cannot live around people any more.  I don't recall where he goes, although I think the last part of the book features people from Earth trying to get him back for another mission (perhaps one for which his uncontrollable telepathy might be useful).


I read about BCryptPasswordEncoder here and I don't understand why this would be used rather than a hash+salt, there is no secret key involved all it takes to for an attacker to crack it is gaining access to the hash and using the algorithm's decode. I thought hash+salting required an external key as the additional layer of security so an attacker would require 2 pieces, the hash and the key.  Or are you suppose to use this then the salt in addition?  All the attacker has to do is run the .match with a password if they obtain the hash  BCryptPasswordEncoder passwordEncoder = new BCryptPasswordEncoder(); String password = ... // Password entered by user String dbPassword       = ... // Load hashed DB password  if (passwordEncoder.matches(password, dbPassword)) {  }   But with a key not stored in the hash an attacker wouldn't be able to just run a decoder against a string they'd need the external key. So how is this more secure than using an external key?

The current top-voted to  states:     Another one that's not so much a security issue, although it is security-related, is complete and abject failure to grok the difference between hashing a password and encrypting it. Most commonly found in code where the programmer is trying to provide unsafe "Remind me of my password" functionality.   What exactly is this difference? I was always under the impression that hashing was a form of encryption. What is the unsafe functionality the poster is referring to?


I got The Elder Scrolls V: Skyrim not too long ago so, I'm a total noob. I want a horse, but im literally too broke for it. Is there any faster way to get money than just doing the quests?

In Oblivion, I had two favorite money-makers:   Dump all my stuff except some basic armor and potions, and raid an oblivion tower. The armor and weapons was worth lots, and selling it in Anvil made a lot of cash fast. Harvest an entire farm's worth of crops, create 'restore fatigue' potions and sell them.   Skyrim seems to spoil this:   Merchants have a max-amount per day/QOD/... instead of per item You can't carry as much (or maybe I have yet to discover the strength/feather spells) Alchemy is a lot harder (most common items go into food recipes now, which don't sell for those prices) On top of that, once a dungeon is cleared, it doesn't respawn - so no 'farming' familiar dungeons?   What are some easy/repeatable money making methods in Skyrim? Which are most efficient effortwise/real-life-time wise?