Pipe/redirect password into ssh for automatic login?

I use ssh to connect to an account based on Kerberos. My Kerberos tickets are only valid for 24h and are not renewed every time I login. Instead they expire and when that happens, ssh keys can't be used for password-less logins since my home directory is not mounted on the shell server, and hence, sshd can't read my authenticated keys.  I don't really care about the security for this account, I only use it to open a tunnel to access an SMTP-server (that in itself requires secure authentication) and therefore wonder if it is possible to somehow echo/pipe/redirect my password (which, BTW, due to stupid password requirements is impossible to remember so I have to have it as a fixed entry in a clipboard manager) into my ssh command so I don't have to enter it manually every time?  ssh -l user host < password


What's worse, too many entities or too many tables?

I just had a question about database design, I am in fairly early learning stages of this so bear with me.  Suppose I have a parent table called "Projects" each "Project" Entity can have any number of "Attachments" and each "Attachment" can have any number of "Anchors".  I can only see a few possible solutions for this. Estimations assume 10 years use of this database: 300 Projects/year * 3 Attachments/Project * 20 Anchors/Attachment  Solution 1 (My initial design idea):  Involves 3 tables. "Projects"->"Attachments"->"Anchors"  Number of Tables: 3  Max entities in a table: 180,000 in "Anchors"  Solution 2:  Involves 2+n tables.  "Projects"->"Attachments"->"Anchors[n]"  Number of Tables: 9,002 (9,000 Anchor Tables)  Max entities in a table: 9,000 (In Attachment Tables)  Solution 3:  Involves 1+n1+n2 tables. "Projects"->"Attachments[n1]"->"Anchors[n2]"  Number of Tables: 12,001 (3,000 Attachment + 9,000 Anchor)  Max entities in a table: 3,000 (In Project Tables)  To summarize:  What's worse, more entities or more tables? AND/OR Is there simply a better design for this situation that I am unaware of?


Slope of an Angled Line Intersecting a Tangent Line

I know that to find the slope of a tangent line at a point $(x, y)$ the general form is $y-y_1 = f'(x_1)(x-x_1)$, and the equation of a line perpendicular to that tangent line is $y-y_1 = -\frac{1}{f'(x_1)} (x-x_1)$. So my question is, what is the general form for an equation that intersects the tangent line of a function at an angle of $\theta$? Thanks in advance!


Find eigen values of $B = \begin{bmatrix} 0 & A^* \\ A &0 \end{bmatrix}$

$$B = \begin{bmatrix} 0 & A^* \\ A&0 \end{bmatrix}$$  I think that $\det(B) = \det(A) * \det(A^*)$ and probably eigen values just get squared. What is the right answer?  EDIT: $\operatorname{rank}(B) = 2 * \operatorname{rank}(A)$, so there are twice more eigenvalue or their multiples. And the additional eigenvalues are just negatives of the eigenvalues of $A$ (Thanks to Simon).  Still can't figure out.


A question on " But guess we'll cry come first of May "

In the lyrics of First of May, there is a line "But guess we'll cry come first of May". What is the meaning of it? Especially, what is the meaning of "come first of May"? What will "come first of May"?   Thanks


I have looked at this question and don't understand almost everything about it. Looking for a detailed answer.  For any two vectors a and b,  Show that $|a+b|^2 + |a-b|^2 = 2|a|^2 +2|b|^2$


annoyance: latest version of Skype under Standard (non-admin) user on macOS 10.13

I always run my systems under an Admin \ Standard user dichotomy.  In other words, I always use my system as a Standard user and never login to the Admin user (except when doing the initial clean install and configuration).  This seems to mostly work on macOS ().  However, I specifically have an irritating problem with Skype, where it will pop up a authentication Window stating:     An update is ready to install.  Skype is trying to add a new helper tool.   ...and asking for my Administrator account credentials.  Now, I've had other programs ask for similar authentications for updates and installs from time to time, and I simply put in my credentials and it installs some update quickly and I continue about my business.  No problem.  However, with Skype, it seems something is simply not working - like perhaps it wasn't designed with Standard users in mind.  After entering my Administrator credentials - nothing installs.  The authentication window simply disappears and nothing happens.  But even worse... the window will inevitably appear again after an hour or two.  So I'm constantly being harassed with this notification, and no matter how many times I authenticate the request (dozens of times so far), it just keeps coming back.  Note that I had this same problem back in Yosemite running whatever version of Skype was the latest back then.  I recently did a clean install of High Sierra, and I had hoped this problem would disappear.  Nope.  Any ideas?


Travel to Australia with new passport (with visa in old passport)

I was granted a visa to Australia few months ago. I’d like to travel to Australia in few days. However, I’ve just renewed my passport and I don’t have enough time to inform them about my passport renewal. Can I travel to Australia by carrying both my old and my new passports?


I have a string of assorted white-space:  e.g.  "\t\r "   I need to display it in an error message, but just showing white-space isn't helpful.  Is there a method to encode the string for displaying?


Why does debugger show errors in browser and not break into code

Basically whenever I debug through my asp.net MVC application and hit an unhandled exception I get the error in the browser - it doesn't step into the application as usually allowing me to view variables etc.  As seen in the picture below the browser merely displays the error:    How do I make the debugger step into the code when an unhandled exception occurs.


Should questions where a problem arose from a typo be closed?  Here is a recent example:    The problem was a misspelled _gaq (written as _gat).   Should these be closed? Surely they're of no use to anyone once the OP recognizes the mistake. If so, what justification should be given? Not a real question? Too localized?     Just to be clear, the question linked above actually was not broken due to a typo. This was my mistake, and raises some other interesting questions. See the discussion below.  If anyone feels like editing this question with examples of actual typo questions, go for it.


What is the point of a retirement plan contribution limits (with after tax dollars)?

Based on the 2021 numbers: 401(k) elective deferrals are limited to 19,500. Limits here make sense as savings offer obvious advantages: pre-tax contributions in case of regular 401(k); non-taxed distributions in case of roth (401)k. Additionally, individuals are allowed to setup after-tax contributions. As the name suggests, these contributions are made with after-tax dollars and earnings are taxed when distributed. This is no different than any investment account. The annual IRS limit for after-tax contributions is set at 58,000 in 2021. What is the point of that limit? Why should I prefer after-tax contributions when I can open a zero-commission investment account and buy/sell the same Vanguard ETFs without limits, paying taxes on earnings?


Let $T,S$ be linear transformations, $T:\mathbb R^4 \rightarrow \mathbb R^4$, such that $T^3+3T^2=4I, S=T^4+3T^3-4I$. Comment on S.

Let $T,S$ be linear transformations, $T:\mathbb R^4 \rightarrow \mathbb R^4$, such that $T^3+3T^2=4I, S=T^4+3T^3-4I$. Then S is:   one-one but not onto onto but not one one invertible non-invertible   (One or more correct options)  My attempt: $S=T^4+3T^3-4I=T(T^3+3T^2)-4I=T(4I)-4I=4T-4I$  How do I go about proving or disproving my options?   My thoughts on options # 1. and 2.: I'm guessing $S$ is one-one if $Ker(S)=\theta$ is one way to go, but how do I obtain the kernel when I don't know what the transformation is? $Ker(S)=\theta$ if $T=I$, which does satisfy $T^3+3T^2=4I$. But so can other $T$s.   My thoughts on options # 3. and 4.: $S$ is invertible if $det(S)\neq0$, which is possible $det(T-I)\neq0$, i.e. $T\neq I$. How do I show that?  Please help!


Spambots causing server crashes. How do I block them?

I have a Drupal 7 website on a shared hosting account that uses an Apache server. It is getting continuously battered by spam bots who try to post junk comments and create fake accounts. What methods can I use to block them from accessing the site and/or doing any operations there.  Currently, I have the following modules installed to block and combat spam:  Spambot -   Spamicide -   Hashcash -   AntiSpam -   Cloudflare -   I tried installing Bad Behavior (), but there appears to be some error in its installation procedure.  I do not want to use captcha to block spambots.


Sufficient Identification for Intra Schengen flights

If one takes a direct flight from one Schengen member state to another, what's the minimum sufficient ID that needs to be provided to board the flight?


How do I add permissions via command line for "everyone" on external HDD

I have an external HDD and I kind of messed up the file permissions but when fixing it I thought it is ok bc with my username I can access the files perfectly fine. Now that I use this with two PC (actually ATM I don't have access to my other PC) I can't access these files.  The problem is this directory has hundreds of folders with no permission for "everyone". I would like to give it the default permissions including have all access for the user "everyone". How do I do that via command line for these hundreds of folders?


PHP Login system using Cookies and Salted Hashes

I am developing a PHP-based login system. Each user has an ID(a number) and a password, which is stored as a salted hash.  I am able to figure out if a login is sucessful or not, but now I need to store that information somewhere(so that the user is not permanently logged out).  In the past, I've played with $_SESSION variables. However, these seem to be deleted when the user leaves the browser, which is undesired. Also, I can not "assume" that the user won't try to trick the system, so it has to be safe.  So, here are my questions:   Should I use $_SESSION or $_COOKIE? What are the main advantages of each of these approaches? How to implement a 'Remember me' checkbox? Which information should be stored in the session/cookie variable?   Note that no database security issues are being taken in consideration in this particular question.  Regarding number 3, what I mean exactly is:   Should I store the ID and the hashed password of the user in the cookie/session, or Should I store the ID and the non-hashed password of the user in the cookie/session, or Should I store a "SessionID" and the password(hashed or non-hashed?) or Should I store a "SessionID", the "ID" and the password(once again, hashed or non-hashed)?   I want to keep my website as safe but efficient and user-friendly as possible. If a SessionID-based approach is taken, I'd also appreciate some explanation regarding how to store it in the database.  Thank you in advance  EDIT: Eran's and Brian's answers combined seem to be what I need. Unfortunately, I can only mark one of them as accepted. I'll try to go ahead and implement to see which one was more useful.


Solving recurrence $T(n) = T(\lfloor{\frac{n}{2}}\rfloor) + T(\lceil{\frac{n}{2}}\rceil) + cn$ is $O(n\text{log}(n))

So I need to prove that T(n) is $O(n\text{log}(n))$, considering $c>0$ is a constant and using substitution method What I've tried so far: We need to prove that $T(n) \leq dn\text{log}(n), d\geq0$ Assuming that $T(\frac{n}{2}) \leq dn\text{ln}(\frac{n}{2})$, we have $T(n) \leq dn\text{ln}(\lfloor{\frac{n}{2}}\rfloor) + dn\text{ln}(\lceil{\frac{n}{2}}\rceil) + 1$ Removing the ceil and the floor, I'm guessing we don't want to equal both of them to $\frac{n}{2}$, so $T(n) \leq dn\text{ln}(\frac{n}{2}) + dn\text{ln}(\frac{n+1}{2}) + 1$ $T(n) \leq dn\text{ln}(n)-dn\text{ln}(2) + dn\text{ln}(n+1) - dn\text{ln}(2)+1$ $T(n) \leq dn\ln(n) + dn\ln(n+1) -2dn + 1$ And I have no idea how to continue this.


A division program the enters numerator twice and doesn't enter the denominator

I want my program to keep asking the user to enter the numerator and if the input was a number it asks for the denominator it checks if it is 0 or not if 0 it shows error message and if not it completes division  but if the numerator was a string it sends an error message but if it is E or e it exits the program  but the problem is that it asks me to enter the numerator twice and it doesn't ask me to enter the denominator and it devises the first number I enter over the second even if I enter a string it asks me to enter the string twice  package Division; import java.util.Scanner; public class Division{      public static void main(String[] args) {     Object n,d;       Scanner input = new Scanner(System.in);           do{              System.out.println("Enter the numerator: ");             n = input.next();             System.out.println("");              if(input.hasNextDouble())             {                  System.out.println("Enter the denominator: ");                 d = input.nextDouble();                 if (d==0){                     System.out.println("You can't divide "+n+" by 0");                 }                 else{                     System.out.println(n+"/"+d+" is"+Double.valueOf((String) n)/Double.valueOf((double) d));                 }             }             else if(input.hasNextLine()) {                 if(n.equals("e")||n.equals("E")){                     System.out.println("Good Bye");                 }                 else{                     System.out.println("You entered bad data. Please try again.");                 }             }         }while(n.equals("e")==false||n!=n.equals("E")==false);    } }


Could anyone explain how this statement is true? You may notice that this statement is part of the process of adding two independent binomial r.v.'s.  $$ \ \sum_{x=0}^\infty{n \choose x}{m \choose w-x} ={n+m \choose w}\ $$


How to find all objects in the Camera's view with Python?

I have a scene with a many objects and one camera.  I would like to select the objects that the camera sees, even partially.   Is there a way to do that in Python that accounts for the objects bounds?    Note, I know that KD trees and Octrees are used for the lookup. There is  but the example only suggests how to query objects close to a point. I'm not familiar with the math for combining camera frustrum and binary trees lookup.


How do I scroll to an element which is present inside an overflow div which itself is inside an an overflow container?

Everytime I add a new element the page should scroll to the bottom of the inner div (having id = content). Right now scrollTo scrolls to the top of the outer div aka container    // css     .container{       background: #eee;       height: 800px;     }     .inner-div{       overflow-y: auto;       height: 100px;       background: #aaa;     }

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   <button onclick="addItem()">   Add Item   </button>


How do you make buns hollow inside for filling?

Chinese and Korean filled buns are my family's favorite. I've succeeded in making soft breads but never know how to make the buns hollow to inject a cream inside. I know that some recipes simply put the filling inside before baking them but I wanted to know if there is a way to make it hollow inside?


learning linear algebra in a brief amount of time

I'm trying learn linear algebra in a brief amount of time. so  I'm looking for a book on linear algebra which is succinct, enlighting and self-contained. Based on your personal experience which book you think is best to learn linear algebra in a brief amount of time.


Let $I,J$ be left ideals in a ring $A$ such that $\forall x\in I \ \ \forall y \in J$ we have that  $x,y$ are nilpotent. Is then true that every element of $I+J$ is nilpotent? Now, if the ideals are bilateral, expanding $(x+y)^{n_0}$ and "playing" a little bit with the exponent $n_0$ we've proved that the answer is: yes. But I think a different approach is needed with the hypothesis that $I,J$ are left ideals. Any suggestion?


apt-get: reasons for “…but it is not going to be installed”

So once again apt-get bothered me with the infamous message that package installation failed because a dependency “is not going to be installed”:  ~ $ sudo apt-get install php-apcu Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  php-apcu : Depends: phpapi-20151012             Recommends: php-apcu-bc but it is not going to be installed E: Unable to correct problems, you have held broken packages.   As I understand, default is to install all missing dependencies along with the requested packages. What would cause apt-get to refuse to install certain dependencies? (And if there is more than one thing leading to this, how can I find out which it is?)


Best Statistics Textbook For Undergrad Statistics Course

I'm currently an applied math major on the final semester. Currently taking mathematical statistics which im finding difficult. Can anyone recommend a really good textbook with proper worked examples and possibly detailed chapter/section explanations. Im currently using Introduction to Mathematical Statistics - Robert Hogg 7E. Any good recommendations truly appreciated.


I am trying to read txt file, find $id and increment it's value $id=>value. But the problem is that when I want to save changes the first new line is ignored so  10=>26 30=>11 33=>22   became this after I run the script  10=>2730=>11 33=>22   This  10=>26 30=>11 33=>22   Should result in this  10=>27 30=>11 33=>22   Here is the code. I am using $id = 10.   $tmp= "";     $file = file_get_contents(dirname(__FILE__) . "/requests.txt", "r");     $file = explode("\n", $file);     foreach ($file as $product){          $data = explode("=>", $product);         if($data[0] == $id) {             $data[1] += 1;             $product = $data[0]."=>".$data[1];             $tmp = $tmp.$product."\n";             continue 1;         }         $tmp = $tmp.$product."\n";     }     echo $tmp;     file_put_contents(dirname(__FILE__) . "/abc.txt", $tmp);


I used all options on the web but this seems to trick me every time.  u used flex  vertical alignment  I don't want to add margin or padding.  You can comment to start the discussion.  I am just adding this bcox its asks for more explanation:     .topnav {      overflow:hidden;   background-color: #333;   padding-top: 10px;   padding-bottom: 10px;   padding-left: 5px;   margin: 0px; }   .topnav div {   float: left;   display: flex;   color: #f2f2f2;   font-size: 15px;   margin:auto;   text-align: center;   padding-left: 10px;    }   .topnav div:hover {   background-color: #ddd;   color: black;   margin:auto;   position: relative;   vertical-align: middle; }  .topnav div.active{    color:white;    display:flex;    font-family: Arial, Helvetica, sans-serif;    font-size: 20px;    margin:auto; }

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Cannot rm or cp files with a wildcard in name

I have a line like this in my script:  rm "$TEMP_DIR/*.txt"   It fails with this output:  rm: cannot remove 'temp/*.txt': No such file or directory   I don't understand why doesn't that work. What am I doing wrong?


Calculate ellipsoidal area for a projected layer in PyQGIS 3

I'd like to loop though each feature in a layer and calculate its ellipsoidal area using QgsDistanceArea() in PyQGIS 3.  Everything works fine on unprojected layers, but I get strange results when input layer is in projected CRS.  So far I have written this:  from qgis.core import *  def calculate_area(in_lyr_name, ellipsoid, units):     input_layer = QgsProject.instance().mapLayersByName(input_lyr_name)[0]      area = QgsDistanceArea()     area.setEllipsoid(ellipsoid)      features = input_layer.getFeatures()     feature_area = 0     error_features_counter = 0      for i, feat in enumerate(features):         geom = feat.geometry()         polygon_area = 0         try:             if geom.isMultipart():                 polygons = geom.asMultiPolygon()                 for polygon in polygons:                     polygon_area += area.measurePolygon(polygon[0])             else:                 polygon = geom.asPolygon()                 polygon_area = area.measurePolygon(polygon[0])              feature_area += polygon_area          except AttributeError:  # catches NoneType geometries (broken etc.)             error_features_counter += 1             pass      # calculated area is in sq. metres (see the "else" case)     if units == 'km²':         final_area = feature_area / 1e6     elif units == 'Ha':         final_area = feature_area / 10000     else:         final_area = feature_area     return final area, error_features_counter   How do I get a constant result that does not depend on the presence of projection?


I am flying from Johannesburg to Paris. I want to spend a couple of days there. Then I am going to Amsterdam with the train to spend a couple of days there. I am flying back from Amsterdam to Johannesburg.  I did apply for my Netherland visa (Schengen visa) - do I need to apply for another visa for Paris as well?


In Glass shader, transparency in not displayed

I want that when I apply glass shader then transparency must display but it is not , when I applied glass shader then reflection of trees are dipplayed instead of transparency , why? please help me, I am using blender 2.8, this problem is in both cyclic and EVEE


Is it possible to save `bc` command line history?

bash has a handy file .bash_history in which it saves the history of commands and on the next execution of bash the history is populated with saved commands. Is it possible to save bc command history to a file in the same way and then load it on startup so that bc history is preserved? I tried reading  and it mentions readline and libedit. From ldd /usr/bin/bc I see mine uses readline and readline has  and read_history functions. Is this functionality implemented in bc or to do it I'll need to patch bc?


I have a Rest Web Service class that exposing Get Function. I am trying to get the entire URL of the request to save it in logs. According to the  I could get it, without beginning of the URL, with : req.requestURI  But when I use it, I only get 'Account/' if I take as example the Get function in the documentation, without base URL and without parameters. So the question is how I can get the entire URL of the Request including base URL and Parameters? for example:  https://myDev.my.salesforce.com/services/apexrest/GetAccountInfo?IdNumber=1561&AddressId=53812245&Apartment=8


How to know whether the data is linearly separable?

The data has many features (e.g. 100) and the number of instances is like 100,000. The data is sparse. I want to fit the data using logistic regression or svm. How do I know whether features are linear or non-linear so that I can use kernel trick if non-linear?


How much heating does Earth inner core provide to the surface?

Compared to the energy that the Earth's surface receives from the Sun, how much power comes from the inner melted core?  How important is this contribution to the surface temperature?


Driving force and mean of a particle wave function

I am currently undergoing a course on introduction to quantum mechanics and we took the historical approach. I'm currently at DeBroglie wavelength. He introduces the wave particle duality in matter, from which will arise the wavefunction of a particle for example. And we have seen that this wave can take a lot of forms and shares most properties of other waves that we have seen (e.g. water waves, electromagnetic waves, and so on), but I can't seem to grasp two things:   We know that physical waves (water waves or sound) need a physical mean of propagation in order to transfer its energy, but electromagnetic radiation doesn't. It can propagate in vacuum! However, this idea that waves propagate in nothingness does not fit in my mindset, it just can't be! Although, one could argue that, for electric charges, the waves travel due to perturbations in their own field, since it extends itself to infinity and so any changes in the field would be noticeable (for photons I'll guess its a bit different, but that's another question). And so, it kind of has some "mean" to propagate, but I can't see where or "on what" do the wave functions live or travel! Do they simply "exist"? That can't be. What created them? and this leads me to the next question; What is the wavefunction driving force? we can easily create sound, and electromagnetic waves by applying some driving force to their system. But for a particle we assume that it merely has a wave associated to it. But how did it even get there in the first place? Does this wave exist from the beginning of time? We could say and argue intensely "It's a property of the particle!!! and when we "mess" with the particle we change the wave function so this wavefunction is always changing, but where does it come from??   I know that it will always be impossible to answer all the why's but if we have a theory that fits beautifully to our experimental data it's worthwhile to answer as many fundamental questions as possible


80s movie with futuristic vehicle with dome on top in desert-like universe

I remember watching it on HBO all the time as a kid.  Vehicle was gray, had a dome up top and possibly a dome on back.  It had huge tires strapped together with bungee cords.  It broke down and a girl shows up. Lots of creatures throughout, for example a swamp with paper-like ghouls. Eventually a thunder-dome-like setting with a bionic villain attached to some sort of robotic arm to move around, like a spider web. He had a circle-lightning-looking light behind him.


Does the shape of a containter affect the apparent mass of liquid inside it when measured by a scale?

For both containers it is true that:  $p_{bottom}=p_{atm}+\rho gh$ and $F_{bottom}=a*p_{bottom} \iff F_{bottom}=a*p_{atm} + a\rho gh$  I do not know how a scale functions, but I guess that the only force it can count is the force by the liquid on the bottom of each container (the only surface that is in touch with the scale is the bottom of the container). Thus, if we measured the mass of these two masses of water (lets assume that the mass of the containers is negligible) it would appear to be the same in each case. Am I right?


proof or disprove :If p is a prime number of 5 or more, there is no integer n satisfying $p + 1 = n^2$  first attempt: suppose $p>5$ and $p$ is prime and prove that there is no n integer that satisfy $p+1=n^2$. let $ p=7$, $n= \sqrt {p+1}$ , $n= \sqrt 8$ and is not integer   i think this proof is wrong? because i only proved for p=7  second attempt: let $p=n^2-1 $,$ p=(n+1 )(n-1)$, since $p$ is prime and bigger than 5 by assumption , $n-1=1$, $n=2$, $p=3.2$ , this contradict the fact that p is prime and bigger than 5, hence there is no integer n that satisfy $p + 1 = n^2$ is this looks fine?  now im trying to proof by contrapositive, there is n integer satisfy $ p+1=n^2$ and trying to proof p is prime and p<5  $n=\sqrt {p+1}$ , suppose $p=3$ ,$ n= \sqrt 4$, $n=2$ so there is n integer  satisfy $p+1=n^2$, hence If p is a prime number of 5 or more, there is no integer n satisfying $p + 1 = n^2$  please give review thanks! if im not sure that the proposition is correct, how can i proof by contradiction ?


Is there an equivalent to __DATE__ in AS3?

I'm looking for an equivalent to C/C++'s __TIME__ and __DATE__ compile-time constants in AS3. I want to be able to bake in when the swf was built.  I can write a build script or JSFL to update a constant somewhere, but I was hoping there was something built in.


Undefined reference error when trying to overload the >> operator in a template class

I am trying to overload the >> operator in my template class as a friend function.The problem occurs when I want to read an object of that class;I get the following error: undefined reference to `std::istream& operator>>(std::istream&, ContBancar&)'.  I have checked this post () and I have tried the second approach which is found in the code below.  //ContBancar.h //included all the necessary libraries  template<class T> class ContBancar; template<class T> istream& operator>>(istream&, ContBancar<T>&);  template<class T> class ContBancar {     string detinator;     string dataDeschidere;     T sold; public:     ContBancar(string det="DefaultDestinatar", string data="NoData", T sol=T(0)):detinator(det),dataDeschidere(data),sold(sol){}     friend istream& operator >> <T>(istream &, ContBancar<T> &);  };    //ContBancar.cpp #include "ContBancar.h"  template <class T> istream & operator>>(istream &in, ContBancar<T> &ob) {     in>>ob.detinator;     in>>ob.sold;     in>>ob.dataDeschidere;     return in; }


Condense two ternary operators into a single one-liner?

I'm parsing multiple csvs that contain overlapping fields. I'm first trying to check if a field exists in the csv being parsed, and then check if that value exists in a dictionary. If that value doesn't already exist, then I want to append the value to the dictionary, so that I can later write all of the unique values to a separate file.  I needed to reduce this:  if 'ZIPCODE' in row: ZipCode = row['ZIPCODE'].upper() else: ZipCode = ' '    and was directed to ternary operators:   ZipCode = row['ZIPCODE'].upper() if 'ZIPCODE' in row else ' '   The second check is an if else for the Dict:  FieldDict['ZipList'].append(ZipCode) if ZipCode not in FieldDict['ZipList'] else ' '    My question is, is there a way to combine those two comparisons into a single statement? Or, is there a better way to check for uniqueness in both the csv and the dictionary.  **** figured it out ****  FieldDict['ZipList'].append(row['ZipCode'].upper()) if 'ZipCode' in row else ' ' if row['ZipCode'] not in FieldDict['ZipList'] else ' '


How to work around wildcard inside double quotes?

In bash, the file globbing * doesn't work inside double quotes, but my filename contains whitespace, so I need to double quote filename before passing it to a shell script. How can I do that? For example myscript.sh "0$i*.pdf"  where the pdf files may be "01a b.pdf", "02c d.pdf". I use i to store 1 and then 2. Thanks.


Regarding syntax for object creation using new keyword. I know that syntax to create an object is:  Foo ref = new Foo();   Do java language in itself provide some mechanism that can create object other than standard syntax as mentioned above?  I have knowledge that Scala has such functionality or may be some other JVM compatiable language but I want to know from just core java point of view.  Without using keyword 'new' and assignment operatior '='. For example it can be like Foo ref Create(). ? Now I want to develop 'Create' method to replace traditional syntax.


android error 495 while downloading application , why is there no solution for it?

tried almost every solution but faced very frequently. Android should deliver a fix for it and at least show more details on the failure. almost could not download from weeks due to 495 error.


\big parenthesis not much bigger than simple parenthesis in 11pt font

I frequently use simple and larger parenthesis in math mode, like what is shown in the MWE below:  \documentclass[11pt,letterpaper,twoside]{book} \usepackage{lmodern} \usepackage{amsmath} \usepackage{mathtools}  \newcommand*{\bigs}[1]{\vcenter{\hbox{\scalebox{1.25}{#1}}}}  \begin{document}  Blabla bla bla blabla :     \begin{equation}         \Big( c \, \bigs( \big( (1 + (x - y^2)(a + b) \big) \bigs) \Big) = \tfrac{3}{4}.     \end{equation}  \end{document}   I usually don't use the \left \right variants, since I find them too big, and also for other reasons that aren't relevant here.  The \big( \big) commands give a nice output when the document is written in 12pt size.  The difference with simple () is clear.  But then, If I reduce the font to 11pt, the difference becomes very small, almost negligible.  Why is that?  To solve this, I defined a small macro to give something between the simple parenthesis and the \Big version.  But I'm now wondering why I have to do this and if this a proper way of doing things in LaTeX.


I send my initial Ph.D. proposal to my prospective supervisor, but there was no answer to the document receiving confirmation

A week ago, on July the 16th,2019,  I have sent my initial PhD proposal to a prospective supervisor in New Zealand who I have previously made direct contact with, after 4 days I sent another email to make sure he received my documents, but there was no response. I just want to make sure that he can open my file without difficulty. What am I supposed to do now?


Meaning of -- in set command in shell script

What is the meaning of set -- $PATH in shell script? Is this the same as set echo "$PATH" ? What is the significance of -- here?


What are the practical implications of a name change for international travel and activities abroad?

I am considering a name change, which seems to be a relatively straightforward action, when one remains in the same country: certain documents are replaced with new ones bearing the new name, and others are presented together with the name change document.  However, I travel internationally multiple times per year, and I often change temporary residence from one country to another. So I often deal with immigration and similar things. Furthermore, I have a lot of things going on like work and studies.  Quite obviously, if I change my name, I would often have to produce a proper translation of the name change document, which may include notarized translation thereof with apostille or, for example, traduction assermentée in France.  However, it would be great to hear about experiences of people, who have dealt with this issue first-hand, so I can weight the disadvantages against advantages of this correctly. In particular, I would like to know if anyone has encountered unforeseen difficulties with this, and how people rate the overall difficulty of such experiences.


Every Ideal of the ring $R \times S$ (where R and S are rings) is the cartesian product of the ideals $J_1 \subseteq R$ and $J_2 \subseteq S$

I’m looking for some hints. Let J be an ideal of $R \times S$. I have already proved that  $$J_1 = \{a \in R / (a,b) \in J \; for \; some \; b \in S\}$$ $$J_1 = \{b \in S / (a,b) \in J \; for \; some \; a \in R\}$$ are ideals of R and S respectively.  Also, I proved that if $J_1$ and $J_2$ are ideals of R and S respectively, then $J_1 \times J_2$ Is an ideal of $R \times S$. But I don’t know how to conclude the proof.


Check if checkbox is selected using JQuery

I am inserting checkbox using JQuery. When a user click "Add Checkbox" button, the checkbox appears. Now once the user selects this checkbox, I want to get the details i.e value or text of that particular checkbox. How to do that ?    $(document).ready(function() {   $('.btn-check').click(function() {     $('.getcheckbox').append('<input class="check-box" type="checkbox" name="vehicle" value="Bike"> I have a bike
');   });    $('.check-box').change(function() {     if ($(this).is(':checked')) {       console.log("tick");     }   }); });

 <button class="btn-check">Add Checkbox</button>


Is there anything like Stack Overflow for discussions?

Let's say I'm going to write an article why I think a new GUI Library needs to be developed. Is there any place to do this? It would be a longer blog style article, so not something what IMHO belongs on Stack Overflow. But for obvious reasons I don't want to start just another blog.  So do I have to wait for a DiscussionOverflow.com or is there already something like it?


How to reconstruct an image after performing PCA on face image dataset (eigenfaces)?

I've performed PCA on face images dataset and I'm not sure how can I use the most informative principal components to show the "reduced" image.  The original image is 96*96 pixels (96*96 = 9216) and I use a sample of 70 images here (70 rows and 9216 column). We get 70 principal components (min{num of samples, num of features}=70).    How can I re-construct a 96x96 image in order to show the eigenfaces? I want to show my students how the eigenvectors "predict" the real data.  The dataset I'm using .  The code:  install.packages("foreach")  file ='C:\\I\\Love\\Data Science\\face.training.csv' data_all = read.csv(file , stringsAsFactors=F) dim(data_all) #7049   31  # use only 70 first images data = data_all[1:70,] names(data) str(data)  # extract the images data im.train <- data$Image     data$Image = NULL  # each image is a vector of 96*96 pixels (96*96 = 9216). library(foreach) im.train <- foreach(im = im.train, .combine=rbind) %dopar% {   as.integer(unlist(strsplit(im, " "))) }  # im.train is a matrix of pixels 70x9216  # show picture number 2 im <- matrix(data=rev(im.train[2,]), nrow=96, ncol=96) image(1:96, 1:96, im, col=gray((0:255)/255))  # Apply PCA pca <- prcomp(im.train,                  center = TRUE,                  scale. = TRUE) ## using correlation matrix  # There are in general min(n − 1, p) informative principal components in a data set with n observations and p variables. Hence, pca$x is 70x70  # Standard deviation of each component pca$sdev  # A numeric matrix which provides the data for the principal components analysis pca$x     dim(pca$x)   # The print method returns the standard deviation of each of the PCs,  # and their rotation (or loadings), which are the coefficients of the linear combinations of the continuous variables. print(pca)  #The summary method describe the importance of the PCs. summary(pca) #The first row describe again the standard deviation associated with each PC.  #The second row shows the proportion of the variance in the data explained by each component  #while the third row describe the cumulative proportion of explained variance.    # plot method returns a plot of the variances (y-axis) associated with the PCs (x-axis).  # useful to decide how many PCs to retain for further analysis.  plot(pca, type = "l")


How is consumer secret key adding security to Oauth 2.0?

I am trying to understand what additional security the the consumer secret(client_secret) for OAuth 2.0 provides. If one want to avoid using the consumer secret when authenticating you can use the User Agent flow rather than Web Server flow.  As far as I can see there is no way to restrict which flow that you allow to be used for your connected app. So what is the purpose of the consumer secret when anyone can easily avoid using consumer secret for authentication by selecting a different response_type(=token) in order to retrieve an access token?  Is this not just like having two doors into the same house. One with two locks, and the other with just one?


Why doesn't appending a message to a key instead of vice versa defeat length extension attack?

It's well established that H(K||M) is vulnerable to length extension attacks for SHA-2 and other hashing algorithms, and instead an HMAC construction should be used. However - why can't H(M||K) be used instead? Will this also be vulnerable to length extension attack in the same way?


How to find out exactly what is transferred through my router?

I am on a quota-based internet where I am. I have a USB 3G modem that plugs into my TP-Link MR3420. My quota is being drained quickly, but only my wife and I connects to this router and during the day I am out at work. Wife is not a power user either she only uses Instagram, Facebook, Whatsapp, BBM, and some email and general browsing. Yesterday suddenly more than 1GB was drained when I wasnt home. I installed Data Usage app on our iPhones and none used that much. So either someone is stealing my internet or the ISP is cheating me. I looked through the Wifi connection list and didnt see anything suspicious.   What can I do to know exactly what goes between our devices, router, internet? I am hoping to find something that can tell me exactly which device connected to what server, up/download how many KB, and at what time.   Appreciate your help


I have this desktop computer im not using. I want to use it for file storage for all types of files. I also want to share these files to windows computers and stream video to tablet and phones. The streaming will be only localy  What software do i need and how would i go about this?


Proof of the First Isomorphism Theorem for Rings

The statement is the First Isomorphism Theorem for Rings from Abstract Algebra by Dummit and Foote. I'd like to check if all is ok. In particular I'm a bit worried about the (*) line. It looks a bit awkward, but is it too bad? Any suggestions?  Theorem:  1) If $\varphi:R \rightarrow S$ is a homomorphism of rings, then the kernel of $\varphi$ is an ideal of $R$, the image of $\varphi$ is a subring of $S$ and $R/ker \varphi$ is isomorphic as a ring to $\varphi(R)$.   2) If $I$ is any ideal of $R$, then the map $R \rightarrow R/I$ defined by $r \rightarrow r+I$ is a surjective ring homomorphism with kernel $I$. Thus every ideal is the kernel of a ring homomorphism and vice versa.  Proof: Let $\varphi: R \rightarrow S$ be a ring homomorfism. If $r \in R$ and $r' \in ker \varphi$, then we have $rr',r'r \in ker \varphi$ (so that it is closed under multiplication by elements of $R$) since $$\varphi (rr')=\varphi (r) \varphi (r')=\varphi (r)0 =0=0 \varphi (r)=\varphi (r') \varphi (r)=\varphi (r'r);$$ since $ker \varphi$ is also a subring of $R$, it is an ideal of $R$. It's clear that $\varphi (R)$ is a subring of $S$. Now, let $I$ be an ideal of $R$, so that $R/I$ is also a ring, and define $\pi:R \rightarrow R/I$ by $\pi (r)=r+I$. We know $\pi$ is a group homomorphism with kernel $I$, and for $r,s \in R$, we have $$\pi (rs)=(rs)+I=(r+I)(s+I)=\pi (r) \pi (s),$$ so that $\pi$ is in fact a ring homomorphism. Define then $\phi: R/ker \varphi \rightarrow \varphi(R)$ by $$\phi (r+(ker \phi))= \varphi (r),$$ for each $(r+(ker \phi)) \in R/ker \varphi$, for some $r \in R$. This is well defined because  if $r' \in (r+(ker \varphi)),$ then $$\phi (r'+(ker \varphi))=\varphi(r')=\varphi(r)=\phi (r+(ker \varphi)).$$ Also, this is a ring isomorphism because for each $\varphi (s) \in \varphi (R)$ for some $s \in R$, we have $$(*) \ \phi^{-1}\{\varphi (s)\}= \phi^{-1} \varphi[r+(ker \varphi)]= \phi^{-1} \varphi[\pi^{-1} \{r+(ker \varphi)\}]= \{r+(ker \varphi)\},$$ a set with a single element of $R/ker \varphi$, so that it is a bijection, and for every $r+(ker \varphi), r'+(ker \varphi) \in R/ker \varphi$, for some $r,r' \in R$, we have $$\phi [(r+(ker \varphi))+(r'+(ker \varphi))]=\phi [(r+r')+(ker \varphi)]=\varphi(r+r')=\varphi(r)+ \varphi(r')=\phi [r+(ker \varphi)]+ \phi [r'+(ker \varphi)],$$ and $$\phi [(r+(ker \varphi)) (r'+(ker \varphi))]=\phi [(rr')+(ker \varphi)]=\varphi(rr')=\varphi(r) \varphi(r')=\phi [r+(ker \varphi)] \phi [r'+(ker \varphi)],$$ so that it is a ring homomorphism.


are interesting and all, but are there and scenarios in physics (either confirmed or hypothetical) where fractional calculus is part of a model?


Assume h is an increasing function from the set of real numbers to the set of reals. Show h(R) connected implies that h is continuous.

Assume h is an increasing function from the set of real numbers to the set of reals. (h: R -> R). Show h(R) connected implies that h is continuous.


How do I correct missing departure records?

I am a Canadian citizen. A few years ago, I had a four-month internship in the US. I entered on a J1 visa. After completing it and returning to Canada, I subsequently did two more four-month internships, both on J1 visas as well. However, when I returned from the second internship, I completely forgot to turn in my I-94 card. When heading to the US for my third internship, the CBP agent obviously noticed this, gave me a big lecture on how I screwed up, almost turned me back home, etc.; nonetheless, he still admitted me and I completed my third internship, making sure to hand in the I-94 card this time.  Some time later, I went to the US for a short vacation. For some reason, I was pulled aside again for I-94 issues, even though I turned in my latest I-94 card. This almost caused me to miss a connecting flight.  I then found that there's an online database where you can check your arrival and departure records. To my surprise, it indicates that there are still two missing departure records, despite the fact that I am in possession of zero I-94 forms (I turned it in after internships #1 and #3, and the CBP agent took the one from internship #2):                     Departure    2013 June 14        MIL - MILWAUKEE, WI Vacation      -->  Arrival      2013 June 08        CHI - DISTRICT OFFICE 9, CHICAGO, IL                    Departure    2012 December 23    SFR - SAN FRANCISCO, CA Internship #3 -->  Arrival      2012 August 25      TOR - TORONTO, ONT. CANADA Internship #2 -->  Arrival      2011 December 31    TOR - TORONTO, ONT. CANADA Internship #1 -->  Arrival      2011 April 28       TOR - TORONTO, ONT. CANADA   I fear that these missing departure records will haunt me every time I try to travel to the US. How can I correct the missing records, even if I don't have the I-94 forms anymore? I still have all of my original boarding passes for the missing departures (all trips were done via air).


What is wrong with the following proof that one is the largest integer

Note: that this is not precisely the same as  that has been asked before.  Let $n$ be the largest integer. Then $n>1$. Now $n^2$ is also an integer, and $n^2>n.1=n$. So $n^2>n$. which contradicts $n$ being the largest integer. Therefore our initial assumption is false, and 1 is the largest integer, as claimed.


Permanently disabling Galaxy S3's calling and SMS

I've procured myself a Galaxy S3 and I intend to mess with it.  I'd like to have a phone that runs one app and one app only (mine).   I want to disable calling, texting, app installs. Come to think of it, I still want to be able to receive texts, but not send them.  Removing the base apps isn't necessary as long as they're made non-functional in some other way like crashing on startup or something. Outgoing calls or picking up incoming calls is a no-no.  What's the best way to go about disabling these features?   Here's an "artist's" rendition of what I want to see ideally:


Map labels are smaller in exported image than in print composer

I am trying to export images with legible town name sizes but they keep shrinking to an unreadable size when I export them. I have tried a few solutions based on similar questions but to no avail.  I am using QGIS version 2.18.9 and a number of different map sources (OSM, SIX, Google, Bing).


Why is there a difference between ping "localhost" and ping "local IP address"?

Using cmd and ping on Windows gave me the following results:   Pinging "localhost":       Pinging "192.168.0.10" (local IP address):     Aren't both situations exactly the same?   I mean, I'm pinging the same interface, the same machine and the same address. Why do I get such different results?  EDIT: Here is my ipconfig /all screen:


Let $f:\mathbb{R} \to \mathbb{R}$ be continuous satisfying: $f(x+y) = f(x) + f(y)$. Show $f$ is linear.  What I thought would be simple and still probably is, I'm having trouble with. So to show this function is linear, I have to show it satisfies two properties:  1) for any $x+y \in \mathbb{R}$ that $h(x+y) = h(x) + h(y)$  This one is satisfied, just by definition of the function.  2) for any $x \in \mathbb{R}$ and scalar $c \in \mathbb{R}$ then $h(cx) = ch(x)$  I'm having trouble proving this. Since there is no explicit function which would make this easier I'm left struggling how to apply continuity. I thought perhaps if I said:  "suppose $f$ is continuous at the point $a$. Then by definition:   $\forall \epsilon > 0$ and $\forall a >0$ there exists $\delta > 0$ such that if $|x-a| < \delta \rightarrow |f(x) - f(a)|< \epsilon$.   So I thought if I adapt this definition and instead say $\forall \epsilon > 0$ and $\forall a >0$ there exists $\delta > 0$ such that if $|cx-ca| = |c||x-a| < \delta \rightarrow |c||f(x) - f(a)|< \epsilon$.  I'm not sure that really says anything at all, but it is what i came up with.  Advice on how to proceed?


How to calculate $\lim_{n \rightarrow \infty} e^{-n} (\frac{1}{n}+1)^{n^2}$?

How to calculate $$\lim_{n \rightarrow \infty} e^{-n} (\frac{1}{n}+1)^{n^2}$$?  The result should be $$\frac{1}{\sqrt{e}}$$  But I have no idea how to get it.  I've been only thinking of rules to multiply the $e^{-n}$ through somehow, but I don't seem to find anything. The different quantities also seem to work in different directions making interpretation difficult, since: $$e^{-n}\rightarrow 0$$  $$(\frac{1}{n}+1) \rightarrow 1$$ $$n^2 \rightarrow \infty$$  So these interactions make it difficult to say anything about this.  Perhaps there's a way to develop inequalities that show which terms will dominate when approaching infinity?


how does c++ template work in when we use libs?

I firstly think c++ compiler like g++ generates different functions or classes for different templates in compiling stage, But when we use a lib, lib binary has been made, it has been a fixed binary, just for link, why template still works?


iPhone - Detect (recognize) a visual pattern or object using the device's camera

I would like to develop a simple application to detect (recognize) a certain pattern (lets say the logo of a car manufacturer) using the iPhone's camera.  I don't know from were to start. Can you give me a hint? What framework are available for this type of image processing, are somewhere on the internet some tutorials related to this?  I just know about openCV, but I couldn't find a ported iPhone version.


"Who wants ice-cream?" — Should I say "(not) I" or "(not) me"?

With the enthusiastic question of "Who wants ice-cream?", what is the more correct response?         (Not) I.   (Not) me.      Neither response is a sentence. The first response of "(not) I" sounds stuffy, like it should be followed with an indignant sniff. The second sounds like American idiom and acceptable for casual speech.    What do you say?


Is there is a way to exclude nested subdirectory specified by a path to that dir from grep recursive search?

Or I have to use ack or find for this?  Here's what I want. Say I have this dir structure:  dir/nesteddir/match.txt otherdir/nesteddir/match.txt   How do I exclude first nesteddir only? Is it even possible using grep?  Most obvious answer $ grep -r --exclude-dir="dir/nesteddir" "stringToFind" . doesn't seem to work, nor do any of my experiments with various --exclude-dir paths using globbing, leading ./, etc.   Reading man page and googling didn't help, the only mention of this usecase I found is this question:   It was concluded that this is bug introduced in grep 2.12, but I'm using latest version (2.16) and grep's bugtracker () doesn't mention anything related to --exclude-dir, so I guess either it was fixed or it's an intended behaviour.   Would be really nice to get some clarification.


True or false? If $G$ is a group with the property that $g=g^{-1}$  for all g element  $G$, then $G$ is abelian .prove   true ,inverse exits which is in G,for it to be abelian ,it means that it is commutative that is $ab=ba$


Running yes > /dev/null takes my CPU usage to 99%.    The Macbook Air 2018 have a 2 core CPU (1.6 GHz Core i5 [I5-8210Y]). Why is the "% CPU" taken by this process so high?


How could one show that the number of atoms in an uncountable probability space is at most countable?


Is applying for other positions during the early stages of a PhD you don't like considered bad?

I've recently started a PhD position in a university and I figured out that many aspects deject me. At the moment I'm employed in a test phase of a few months, and this has led me to think of leaving this position if it didn't fulfil me by then. With that in mind,  Is it ethical/professional/acceptable to ask my references for additional recommendation letters, again, for the new positions I'm going to apply to? Is a sign of lack of commitment and interest (and therefore, unprofessional)?  I appreciate your opinions.  PS: Even though I have accepted this position, it never was among my top choices. In fact, my decision was very much affected by the situation of COVID in my country and the market recession. UPDATE The main reasons unprofessionalism strikes my mind are the following. I hope it clarifies my situation more.  I'm in the very early days of my PhD, the transient phase so to speak. So any extrapolation of my current situation to the future isn't reliable. I'm afraid that I'm making my mind during this transition time, before adjusting myself or tasting the research as much as I should.  As far as I can feel, the non-academic aspects of my unhappiness outweigh the academic part; For instance, the cold environment of the campus and the city, the depressing atmosphere of the only accommodation I could find, as well as my flatmates (please look at PS2) who are desperately are looking for jobs in the wakes of the pandemic, all transfer a sense of stagnation to me. Although some of these issues can be solved, I believe they need an immense amount energy and time, probably comparable to the effort I need to put on my research.  I accepted this position with one vital side goal in mind, which (to be honest) is as important for me as the PhD degree if not more: learning the local language (until B1 level). Learning a new language is though, especially alongside a PhD. I know it needs extra focus and perseverance. But with all I have to face (summarized in the previous number), and knowing my personal mental capacity, I'm seriously sceptical about being able to achieve this.   I believe these are decent arguments on a personal level, but maybe not academically. I'm afraid that Academic institutes may find this chain of reasoning unsatisfactory, a set of excuses, or a sign of unreliability. As I'm barely a researcher at this point, I'd be grateful if you can shed more light on these arguments and resolve their (lack of) pertinence to the academic world to me, as an experienced outer observer.  PS2: My flatmates are good people. However, I'd rather like to be surrounded by people who are trying to push forward a meaningful protect with passion. That kind of people whose perseverance inspires others. And I'm not talking about superman; For me, any other PhD candidate is a good example of such a group.)


80's (or earlier) book with gun-like weapons holstered on one's forearm, connected to their wrist nerves to jumps into their hand at will

I read a book in the early 80's (sometime between 81 and 83) that I have been trying to remember the title of for a long time. I got the book from my high school librarian as a reading suggestion, so it may have been a young adult book, but I don't know.   The only think I remember about the story is one of the weapons that the "good guys" wore.   The weapon was a hand gun type of weapon that they wore in a holster that was on the forearm of their gun hand.  The weapon was somehow connected to the nerves in their wrist so that when they tensed their hand or arm in a certain way the gun jumped into their hand.


I was reading a website where common English sentence errors are written -     INCORRECT - He doesn't know to swim.      CORRECT - He doesn't know how to swim.   I know He doesn't know how to swim is a correct sentence. But why is the other one wrong, is my question?  I know that know is a transitive verb. So, the following are correct -   i) He knows swimming.  Swimming is a gerund. We can also use the infinitive form here - to swim  ii) He knows to swim.


$f(f(x)) = \log(x) \forall x > 0$, what is $f$?

I seek a function $f(x)$ such that $f(f(x)) = \log(x) \forall x > 0$ .   If possible, $f$ should be monotonic and $\log(x) < f(x) < x, \forall x > 0$  How would I go about this? Does such a function exist?


Why are the textures i assigned not appearing to the cube?

I tried to add some photos to give the light grey bar on the top some texture but it wont show up. I'm new to blender so any advice or solutions would be great


The limit of the square root of two times the square root of two times.....

i'd like to know how to prove that following sequence  $$\sqrt{2\sqrt2},\sqrt{2\sqrt{2\sqrt2}},\sqrt{2\sqrt{2\sqrt{2\sqrt2}}},...$$  Is convergent, and that it's limit equals two.   In other words, that $$\sqrt{2\sqrt{2\sqrt{2\sqrt2...}}}=2$$  I imagine it's supposed to be simple and straightfoward, but i cant figure it out. I would be grateful for any help you could give me.


How to log out of a Stack Exchange site?

Per the title, where is the logout button?  All the existing questions I can find refer to the previous design of the site, where hovering over your name in the top bar brought up a menu.


How to check that a cubic polynomial is irreducible?

I want to argue that argue that $\pi(\alpha)=\alpha^3+3\alpha+3$ is an irreducible polynomial over the finite field with 5 elements $\mathbb{F}_5$. My approach was just to check that $\pi$ has no roots in $\mathbb{F}_5$. Is this right?


My marriage visitor visa was refused on the basis of a document which was tagged non genuine (offer letter from a registered company)   We are considering filing a pre action protocol explaining our situation and proving that the document is true and genuine and get a response from Home office.   Any advice on filing pre action protocol? We didn't find any good lawyers yet, still searching as most of them we spoke to don't seem professional. We are also considering getting married in another country and applying for EEA family permit, will previous U.K. Visa refusal affect my application for EEA, even when we're husband an wife?   Thanks for any advice!


When I run this command :  apt install libkf5*   I get the following error :  Unable to locate package libkf5*    I'm sure that the packages whose names start with libkf5 exist (tab-completion says so) . So the problem is not about the absence of those packages.(Note the asterisk at the end of that error message , the wildcard's not working at all) I use apt v.1.9. Thanks in advance.


The text size in the Stack Exchange app should be user-configurable

Why can we not adjust the size of the text in the Stack Exchange app? The tiny size text may be unhealthy to my eyes. Can the ability to adjust the text size be added?


How can I check the existence of an element in jQuery?  Currently snip of my code looks like this:  if ($(selector).length>0) {     // This should do something }   Is there some kind of function, or a plugin that could work with this? Is there any better way to approach this?


Dedicated mouse and keyboard for a virtual machine, is it possible?

Let's say I have a PC with two monitors atached. I'm running e.g. Windows Vista natively, and start up a virtual Ubuntu PC. I change to fullscreen mode so that on one Monitor, I see my Windows Desktop, and on the other one, the Ubuntu Desktop. I can now use my mouse and Keybord for both of them.  This works fine, but I'd really like to connect a second mouse and a second keyboard to my physical PC, and do some configuration so that one set of input devices is used for Windows, and another set for the virtual Ubuntu. Then two persons could work at the same time, as if they were using two separate computers, although there is only one physical machine.  I'm currently using Sun VirtualBox and it has a feature to assign specific USB devices to the virtual machine. While this sometimes works for e.g. external disk drives, it never worked for mice and keyboards for me (yes, of course my input devices are attached via USB!).  I'd like to know a solution that works with VirtualBox, but any answer is appreciated, even if another virtualization software or some additional hardware was needed.


I'm a fairly new user with ubuntu. But What's the best/easiest way to get wine to work. It never seems to work for me.  thanks


True /false question about compact set in real analysis

This question was a true /false question in my real analysis quiz today and I am unable to provide a reason for it. Question is : A closed and bounded subset of complete metric space is compact. I think it is not compact but only because any open cover may not have finite subcover but I am unable to provide a counterexample for the same.


Help!  I have a PHP (PHP 5.2.5) script on HOST1 trying to connect to an MySql database HOST2. Both hosts are in Shared Host environments controlled through CPanel.  HOST2 is set to allow remote database connections from HOST1.  The PHP connect I'm using is:-     $h2 = IPADDRESS;     $dbu = DBUSER;     $dbp = DBPASS;  $DBlink = mysql_connect($h2, $dbu, $dbp);   This always fails with:-  Access denied for user '<dbusername>'@'***SOMESTRING***' (using password: YES)   nb: SOMESTRING looks like it could be something to do with the shared host environment.  Any ideas???  BTW: I can make remote connections to HOST2 from my laptop using OpenOffice via ODBC, and SQLyog. The SQLyog and ODBC settings are exactly the same as the PHP script is trying to use.


Method to eliminate $x$ between the equation $x^2 + ax + b = 0$ and $xy+ l(x + y) + m = 0$

If by eliminating $x$ between the equation $x^2 + ax + b = 0$ and $xy+  l(x + y) + m = 0$, a quadratic in $y$ is formed whose roots are the    same as those of the original quadratic in $x$. Then prove either $a =  2l$ & $b = m$ or $b + m = al$.   Initially, I thought of eliminating $x$ but that method seems to be very lengthy. Is there any trick that can help to solve the problem faster?


While trying to create a custom business rule using Apex I got the error:  INVALID_ID_FIELD, SaveAsActivity is not allowed with whatId that is not supported as a task whatId.  ...and found out that it was caused by the method setSaveAsActivity on my code, that was like:  msg.setSaveAsActivity(true); // "msg" is a SingleEmailMessage   What am I doing wrong here?


Problem rebooting after installing Ubuntu 18.04.2 LTS

I'm experiencing some problems after finishing installation of Ubuntu 18.04.2 LTS  I have a Dell Inspiron 15 7567 with the following specs: - SK Hynix SC311 M.2 128GB SSD with windows 10 - Toshiba HDD 1TB (where I created partitions for ubuntu during installation, via bootable usb) - 8Gb RAM DDR4 Sk Hynix 1Rx8 2400Mhz - Intel Core i7-7700HQ (4 physical cores) (6MB Caché, uo to 3.80 GHz) - NVIDIA GTX 1050Ti (4Gb) GDDR5 - Only 3.0 USB ports  On the first try, I did the normal installation without changing any default setting of windows or bios. During the intallation I checked the "Download updates while installing ubuntu" option.  The installation process finished without any problem. After it was complete and after clicking on the "Restart Now" button, the problems started. Firstly, it took a while to begin the process of restarting. Then, the folowwing messages appear:    After reading some possible solutions, I did the specified on the following link:   In my case, since I had a previous installation, i didn't choose the "reinstall" option. I went to "something else" and overwrite the partitions that I created before. The installation went perfectly until it was completed. Again, after clicking the "restart now" button, the same issue appear.  This time, I tried to log in to Ubuntu. It showed me the Ubuntu logo but after that it was freezed. In both cases, hard shutdown was required.  What is the problem? How I can solve it?  Is a firmware bug? or a hardware problem?  Please help me, I'm starting with linux.


When restoring logs in log shipping, when does the restoring stop

We are using LS for reporting purpose. LS backup runs on primary every 15 minutes. On Secondary nightly restore via LS restore job is done daily at 10 PM.  While the nightly restore job is running, additional log backups are being taken and delivered.  Will the restore job restore the logs through the last one present when the job started? Or, will it keep restoring as long as there's another log to restore.  Let's say our log backups are taken at XX:05, XX:20, XX:35, and XX:50. Our restore job usually runs to, say, 6:00 AM. At that point, does it represent our primary database as it was at 9:50 PM (the last log taken before the restore job started), or as it was at 5:50 AM (because after it restored the 5:50 log, it didn't find another, so it quit)?  Naturally, our users want to know for their queries; whether the data reflects 10PM or 6AM can make a big difference.


Passing value type by reference without initializing in c#

I have a very basic question about passing a value type by reference in c#. why c# doesn't allow us to pass a variable by reference if its not initialized? what will be the issue if we do it? lets take for example below code public static void main() {    int i;    SomeMethod(ref i); }  public static void SomeMethod(ref int i) {    i = 10; }  why cant i execute this method? why compiler is stopping me from doing this? what issue will be faced if we pass a unassigned variable as reference?


I work at a weather app. I use a free api to get the weather information. When I try yo run this class i get "null" Why?You can see the json code in the url. It should return "Romania" but it returns "null" and I don't know why.    import java.io.IOException; import java.io.InputStreamReader; import java.io.Reader; import java.net.URL; import java.util.HashMap; import java.util.Map; import java.util.Scanner;  import org.apache.commons.io.IOUtils; import org.json.simple.*; import org.json.simple.parser.ParseException;  public class Weather {     public static URL url;      public void getWeather() throws IOException, ParseException {          url = new URL("http://api.openweathermap.org/data/2.5/weatherq=drobeta,romania");          Scanner scan = new Scanner(url.openStream());         String str = new String();         while (scan.hasNext())             str += scan.nextLine();         scan.close();         System.out.println(str);          String genreJson = IOUtils.toString(url);         JSONObject genreJsonObject = (JSONObject) JSONValue.parseWithException(genreJson);         // get the title         System.out.println(genreJsonObject.get("country"));      } }


In this post-apocalyptic short story, a small group of people are returning from a (failed) effort to save one outpost.  They cross a snowy wasteland to find that the nearest domed refuge has also ceased functioning and are forced to stretch their supplies and physical resources to reach a farther afield one.  The story ends with them barely reaching their goal to find a warm and civilized society inside the refuge. I believe hot cocoa features in the final scene.


So I know that $\mathbb{R}$ is both open and closed. But given a set, $X\subset \mathbb{R}$, $X\ne \emptyset $ that is both open and closed, how does one show that $X=\mathbb{R}$?    Here is my attempt: Using the definitions I was given, $X$ open implies that for every $x\in X$ there is a $\delta \gt 0$, $(x-\delta,~ x+\delta)\subset X$.    Also, since $X$ is closed , $B=\mathbb{R}$\  $X$ is open.    However, I don't know how to proceed. NB: This is not a homework problem.


Multiple assignment and identity for integers in python

I am noticing something peculiar about identity comparison for integers, below and above 256, in python. Take a look at below code.  a = 256 # or any number below b = 256 print(a is b) # True a = 257 # or any number above b = 257 print(a is b) # False   This my guess is that since a number > 256 doesn't fit in an 8 bit memory location, python moves it else where and stores a pointer instead. (I'm not a CS graduate, probably my understanding is completely wrong).  However, if I use multiple assignment. Things are different.  a, b = 257, 257 # or any number above print(a is b) # True   Is this by design? May be for optimizing memory? Why does python behave like this?   ps: I am using Python 3.6.1


How can I see the current Database Mail configuration?

Our SQL Server (2008) instance is configured to send mail and everything is working correctly, but I can't figure out how to view the existing configuration, in particular the SMTP server.   From SSMS I can only start the configuration wizard, and I can't find anything online - plenty of info on how to set it up but nothing on how to view the current settings.   How can I view the existing settings?


Ignoring file sublime-text.lis as it has an invalid filename extension

When I try to install any program by terminal on Ubuntu 14.04 it fails with the same set of errors.  Here's what happens when I try to install sublime-text:


Intuitive examples of importance sampling

My background is computer science. I am fairly new to monte carlo sampling methods and, although I understand the math, I have hard time coming up with intuitive examples for importance sampling. More precisely, could someone provide examples of:    an original distribution one cannot sample from but one can estimate an importance distribution which can be sampled from and adequate for this original distribution.


I'd like to find all xml files containing 'foo', but not containing 'bar'. The command I've put together looks like this:  find -iname "*.xml" -print0 |   xargs -0 grep -FlisZ "foo" |   xargs -0 grep -Flisv "bar"   However the final grep command doesn't seem to exclude files that contain 'bar'. Have I chained the commands correctly?  p.s. I know this can be written in many different ways (and probably a single grep command). However I'm interested in why my chaining is broken.  p.p.s The filenames contains spaces (hence the -print0 in find, the -0 in xargs and the -Z in grep)


Temperature is often said to be average kinetic energy of the atoms and heat the sum of kinetic energy of all atoms.  I dont agree with this definition of Heat as Heat is NOT energy. It is mode of energy transfer i.e. it is energy in transit. Once it is in System you can't distinguish between heat or work or any other form of energy. So temperature is avg kinetic energy and heat is energy in transit. is that right.?


Right now I'm almost tormented by answering the following question:  "How do we handle our errors and issues in an agile environment?"  Scrum is a framework that does not directly dictate how to handle errors. The direct answer would be to treat bugs as Product Backlog Items that should be included in the Product Backlog. If the Product Owner rates their priority as very high, then they will be considered by the development team at the next sprint. Questions:  But is this the only or the right way? So how should you deal with the mistakes in an agile development?


subsection title in header in twosided article

I wish to have section and subsection title in header on every page. Here is my code  \documentclass[10pt,a4paper,twoside]{article} \usepackage{fancyhdr} \pagestyle{fancy} \fancyhf{} \fancyhead{}      \fancyhead[RE]{\sl{\MakeUppercase{\rightmark}}}      \fancyhead[LO]{\sl{\MakeUppercase{\rightmark}}}     \fancyhead[RO]{\sl{\MakeUppercase{\leftmark}}}   \fancyhead[LE]{\sl{\MakeUppercase{\leftmark}}}  \fancyfoot[LE,RO]{\thepage}  \begin{document}                \section{First section} \subsection{First subsection}  \newpage \section{Second section} \subsection{Second subsection} \newpage \subsection{Third subsection} \end{document}   but on the pages with sections there are only sections title in header (for example "First section" on the right side on the page 1 but no "First subsection" on the left side). However on the page 3 it is correctly. Any solutions for this problem? Thanks.


How do I set a recurring event that takes place on the 15th each month but is NOT a weekend?

I'm trying to enter in a reminder for payday.  I'm paid on the 15th of each month.  However, if the 15th falls on a Saturday or Sunday, I'm paid on Friday.  I have no problem entering a recurring event on the 15th.  It's not having it fall on a weekend that I can't figure out.   Someone asked a  but that is always setting a reminder on the 14, so that some months it would be early. It seems this person was trying to make Friday events fall on a Thursday and Sunday events fall on a Monday.  I want anything on Saturday or Sunday to fall on Friday.  I'm hoping to make an .ics event that I would import into my calendar.   worked for me to enter the event for the last day of the month but I can't figure out how to edit it to work on the 15th.  I was trying to edit BYSETPOS and it didn't work.


Can Greasemonkey cause the displayed title to change

I want to change the title showing in a page based on information I pick up from within the page (eg to show the number of inbox messages)  document.getElementsByTagName('title')[0].innerHTML="foo"; does change the title tag, but firefox does not update the displayed title (in window and tags) when this happens.   Is this possible?


I am using QGIS 2.18.16 on Windows 10.    What I want is a label to appear within the boundaries of a polygon.    I select a layer, then select command Layer>Labelling, and I get:    From here, I can change "No Labels" to "Show labels for this layer".  But I can't actually create label text.  I find a clue in a prior question:    “Labelling polygon using QGIS?”    The answer was:  The layer you are trying to label must have at least one attribute field populated with data. You can then turn on labelling in Layer Properties and select which attribute field to use for your labels.  I can enter command Layer>Open Attribute Table, and what I get is:    If I need something in the attribute table in order to apply a label, how do I accomplish that?


Is there any kind of immortality in plants?

I asked a question about  and learned good things about senescence. Now I would like to know about immortality in plants, if there is some kind of immortality in plants and how this occurs - how does it protect itself from senescence?


Initializing and appending Nested Lists in Python?

While trying to append values to a nested list through a for loop,  I came across an issue that the appending values to the list depends on the way the list is initialized.Suppose, I initialize a nested array as:     a=[[[],[],[],[]],[[],[],[],[],[]]]     a[0][1].append(2)  results in     [[[], [2], [], []], [[], [], [], [], []]]  but initializing and appending data in the following manner     a= [[[]]*4]*2     a[0][1].append(2)  results in     [[[2], [2], [2], [2]], [[2], [2], [2], [2]]]  What is the difference between the two as both of them initialize the same type of list?


using double or float as key in std::map

I'm trying to use the std::map where the is double or float up to the third digit after the decimal point, my problem is how to system save the double number when I'm entering 9.20 some time is saved as 9.199999 and then the find function is not working. is there a way to make it work or just use ints or strings as key?


Let $(M,d)$ be a metric space and $x\in M$, $x_n\to x$  So $|d(x_n,a)-d(a,x)|\leq d(x_n,x)$ is a concluse form the triangle inequallty?


What is the smallest (installed size) ubuntu based distribution?

For ridiculously small hard drives (8GB), what Ubuntu Based (although not necessarily official) distribution offers the smallest installed size?  Let me clarify: I still want a certain amount of personal file space, preferably a few gig. I also don't have a problem with performance, while it is mediocre, a 2.6GHz single-core and 1GB of ram suffice to run ubuntu fine, but i find that it  uses 6-7GB of space. I am aiming for closer to 4GB.


Add an icon to the achievement list when new privilege has earned in apps

Achievements list doesn't contain an icon for new privilege for both iOS and Android apps:     Web contains an icon either:    Is it possible to add same icon as in web?


How can I make calls related to a case display in its Chatter feed?

I am using the Service Console in Lightning Experience, and using the Chatter Feed component on the Case layout to display updates to the Case.  If I use the "Log a Call" Quick Action from the Chatter publisher, these calls are displayed in the Chatter feed.  This is the desired behaviour.  However, if I insert a Log a Call record related to the Case any other way - e.g. using the Developer Console, or my CTI system's custom components - the call does not display in the feed.  If I query the record, it looks exactly the same as the record that is created with the Quick Action.  It just seems that the Chatter post is never made in this situation.  I have checked my Feed Tracking settings:   Task has Enable Feed Tracking and Subject checked Case has All Related Objects checked   How can I enable calls created with a custom component (part of a CTI system) to display in the case feed?


Why does this produce "missing \endcsname" error?

I need to dynamically create the name of a macro, where part of the name is based on the argument which needs to be capitalized beforehand. The following MWE illustrates my intention:  \documentclass{article}  \usepackage{xstring}  \newcommand{\CommandOne}{bla} \newcommand{\CommandTwo}{more bla}  \newcommand{\foo}[1]{   \StrLeft{#1}{1}[\strHead]%   \StrGobbleLeft{#1}{1}[\strTail]%   \csname Command\MakeUppercase{\strHead}\strTail\endcsname% }  \begin{document}  \foo{one} \foo{two}  \end{document}   However, this produces   ! Missing \endcsname inserted.   upon compilation. Why, and how do I fix it?


python slicing strings vs lists: inclusive/noninclusive slice index

Suppose I was slicing a list and a string:  num_list = [1, 2, 3, 4] print(num_list[2:]) # => [3, 4]  text_string = 'This is a test string' print(text_string[5:] # => 'is a text string'   So, when I slice the list, the first slice index is inclusive, but when I slice the string, the slice index is noninclusive. What is it like this? Why does string slicing not follow the same ruleset that list slicing appears too?   My understanding of list slicing is that the left slice index is always inclusive, whilst the right slice index is only inclusive when it is left blank.


Can I do something like [a,b,c] = [1,2,3] in node js?

I would like to be able to do this kind of assignment in node js:  [a,b,c] = [1,2,3]   or just like in python  a,b,c = 1,2,3   so that I would have a=1, b=2 and b=3.  Actually the purpose of this is to do something like   [a,b,c] = somefunc()   or for array declaration  [a,b,c] = [[],[],[]]   Any ideas?


How to take screenshot of a page which is larger than the screen i.e. webpage?

I use ubuntu 14.04 LTS. I used Ubuntu screenshot application in my computer. But it can maximum take a screenshot of whole screen.  What can I do if I want to take screenshot of a page which is larger than the screen i.e. webpage?


I'm looking for "Experience Stack Exchange" or probably "Personal Experience Stack Exchange" site (I can't recall the exact name) but can't find it.  I used to visit it few years ago or so.  On that site people used to ask questions about all type of personal experiences including but not limited to: love, relationship, marriage etc, and I'm not talking about "User Experience Stack Exchange".   Any idea what happened to it?


C# .NET: The TabPage of TabControl disabled/enabled implementation

I have found some implementation of the Enabled property for tabPages, since the implementation for it in the UI is hidden, but I do not know how to use it. It might strike as a stupid question, but I really just started with c# and the .net platform. I want to take a variable from the first form, which is a login form that sends a true value if one checkbox is checked or false if it's not, and if it is true, login as an admin that has the privillege to access all the tabs, but if it is false, a user will be restricted acces from some of the tabs. I do not know how to restrict access to these tabs, or allow it. The code is as follows:  Code for the constructor of the form:  public Form1() { InitializeComponent();  this.tabControl1.DrawMode =  TabDrawMode.OwnerDrawFixed; this.tabControl1.DrawItem +=  new DrawItemEventHandler(DisableTab_DrawItem); this.tabControl1.Selecting +=  new TabControlCancelEventHandler(DisableTab_Selecting); }   The function which draws the tab pages:  /// <summary> /// Draw a tab page based on whether it is disabled or enabled. /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void PageTab_DrawItem(object sender, DrawItemEventArgs e) { TabControl tabControl = sender as TabControl; TabPage tabPage = tabControl.TabPages[e.Index];  if (tabPage.Enabled == false) { using (SolidBrush brush =  new SolidBrush(SystemColors.GrayText)) { e.Graphics.DrawString(tabPage.Text, tabPage.Font, brush,  e.Bounds.X + 3, e.Bounds.Y + 3); } } else { using (SolidBrush brush = new SolidBrush(tabPage.ForeColor)) { e.Graphics.DrawString(tabPage.Text, tabPage.Font, brush,  e.Bounds.X + 3, e.Bounds.Y + 3); } } }   The event handler that prevents the tab from being selected if it is disabled:  /// <summary> /// Cancel the selecting event if the TabPage is disabled. /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void PageTab_Selecting(object sender, TabControlCancelEventArgs e) { if (e.TabPage.Enabled == false) { e.Cancel = true; } }   The said variable and the decisional statement:   int cont = Login.accountType; //the variable from the first tab, that decides whether the account is admin type or client type         //the variable is public static int in the first form          if (cont == 1)         {             //display all the tabs, because we logged in as admin         }         else if(cont == 0)         {             //disable the tabs that we do not want the client to access         }


Is it possible to "decompile" a Windows .exe? Or at least view the Assembly?

A friend of mine downloaded some malware from Facebook, and I'm curious to see what it does without infecting myself. I know that you can't really decompile an .exe, but can I at least view it in Assembly or attach a debugger?   Edit to say it is not a .NET executable, no CLI header.


Solve: if $\tan (a+b-c)/\tan (a-b+c)=\tan(c)/\tan(b) $, prove that $\sin 2a + \sin 2b + \sin 2c = 0$

My try :   I can proceed from here but as you all know that it will take more than 1 page , but I want a short approach for it.


Is it ok have to have two search bars on the same page?

I have two search boxes on the page. First one is the universal search in the main navigation bar and the other one to filter map pins based on location. What do you guys think?   P.S I am unable to get usability testing done now due to time constraints.


Sum of series proof $\sum_{i=1}^{n} i2^i$

How can I find the sum of $\sum_{i=1}^{n} i2^i$ in a closed form. I have a feeling I can do this using differentiation of an existing series but cant seem to find it.


How can I implement chance/probability into Python?

I want to have Python print "Yes" 70% of the time, and "No" 30% of the time. How should I go about doing so?


How do I show the left hand side bottom box

How do I show the left hand side bottom menu which is present right after Shift-A added object Torus once I've closed it? It should be labelled Add Torus in this case.


(This is mainly for Stack Overflow, I did personally not check out color schemes on the other sites. But a  has been raised for beta sites.)  I don't think the current style for visited links on Stack Overflow posts is very nice. The text is black and links are #4A6B82 which looks almost like black or a very dark grey on my screen. That's not very accessible (and that's in spite of my good eyesight).  Additionally, links in inline code sections do not get underlined on hover, which makes them even harder to spot. Sometimes I link to documentation by putting a link on (<- like this), and it is very hard to notice that it is even there (apparently, Meta has the same problem…).  I would find brighter links and consistent underlining very helpful.  I'll tag this as [bug] because I think link coloring is actually broken. And the other choices ([feature-request] [discussion] [support]) don't really fit.


I came across this interesting question in a game forum and I couldn't solve it:  Each time a gamer has probability = 1/4 of drawing out an SSR, if the gamer doesn't get an SSR after 3 consecutive draws, the 4th draw is guaranteed to be an SSR. What is the expect number of SSRs after 100 draws?


Reading list and book recommendation on Conformal Field Theory

I have a background in QFT, GR and differential geometry at the level of a master student in theoretical physics. I would like to touch the area of CFT. I know the textbook of Philippe Di Francesco. It may be too big for the beginner like me. Are there some good introductory lectures or textbooks adapted to the needs of beginners?


Proving that $m+n\sqrt{2}$ is dense in $\mathbb R$

I am having trouble proving the statement:     Let $$S = \{m + n\sqrt 2 : m, n \in\mathbb Z\}$$ Prove that for every $\epsilon > 0$, the intersection of $S$ and $(0, \epsilon)$ is nonempty.


When writing large numbers, should a comma be inserted?

I know that it is common to write the number 'ten thousand' as a numeral with a comma delimiting the 10 and the 000 like so: 10, 000  However, I have never seen a comma used for numbers less than 10,000, such as 8000 where, I assume using a comma would look like: 8,000.  Are there any rules relating to when a comma should be inserted into a numeral?  N.b. I live in the UK, so answers pertaining to UK English are preferred.


Can lands that say “Add one mana of any color to your mana pool” be used in a colorless EDH deck?

A couple of other questions have been asked regarding cards that "Add one mana of any color to your mana pool", but    (which, in most cases, have at least one color)  (which would likely also be used in a colored deck, or a non-EDH deck where extra colors don't matter)   What I'm trying to answer now is if those sorts of cards can be used in a colorless EDH deck.  So, for example, if I have one of the big Eldrazi as my commander, I know I can have  in the deck because it has a colorless color identity. But, once it's on the field, can I use it to generate usable mana?


I have a query that is expected to return a few rows but is not returning any results in code. I have some value from an arraylist that I'm wrapping around single quotes and comma to be use in the 'in' operator.  Am I doing something wrong here?  AseCommand cmd = new AseCommand("select * from Customer where ID in (@parmCustId)", conn); cmd.Parameters.AddWithValue("@parmCustId", string.Join(",", arrList.Cast<string>().Select(x => string.Format("'{0}'", x)))); using (AseDataReader dr = cmd.ExecuteReader()) {    if (dr.HasRows)    {       //do something    } }


Let $A$ be an $n \times n$ matrix.  $i)$Prove that if the sum of each row of $A$ equals $s$, then $s$ is an eigenvalue of $A$.  $ii)$Prove that if the sum of each column of $A$ equals $s$, then $s$ is an eigenvalue of $A$.  I think that being an eigenvalue of $A$ implies that $sv=Av$ for some vector $v$. Furthermore, I know that $[a_i] = s$ if we let $a_i$ denote the i-th row of $A$. However, I do not seem to be able to find a link between these two facts. Could anyone please help me out?


$f$ is continuous, $\forall x , \lim_{n \to \infty}f(nx)=0 \implies \lim_{x \to \infty}f(x)=0$

$f:(0,\infty) \to \mathbb R$ is continuous, such that $\forall x \in \mathbb R, x >0, \lim_{n \to \infty}f(nx)=0$. I need to show that $\lim_{x \to \infty}f(x)=0$.  I started with an attempt to come with a proof by contradiction: say $x_n \to \infty$ and $f(x_n)$ does not converge to zero, i.e. $\exists \epsilon > 0$ and $x_{n_k}$ sub-sequence of $x_n$ such that $|f(x_{n_k})| > \epsilon, \forall k \in \mathbb N $. From the continuity follows that for each $x_{n_k}$ there is $\delta_{n_k}>0$ such that   $$|f(y)| > \epsilon, \forall y \in (x_{n_k}-\delta_{n_k},x_{n_k}+\delta_{n_k}) $$  And here I am stuck. I would need a hint how to proceed, not a full answer.


I think I'll be wait by/until thursday before making a decision .  which one and WHY?    "I think I'll wait until Thursday before I make a decision." is correct. Explanation is the same. "I am not going to make the decision sooner than on Thursday." "By" would mean on Thursday or sooner which does not make sense. .....  With regard to the top definitions, If I would make  a decision sooner than thursday or on thursday, must I use the preposition"by" instead of "until"? that is,  I think I'll be wait by thursday before making a decision .


As I was trying to cast a vote with an SE account with <15 rep, I read:  Thanks for the feedback! You need at least 15  to cast a vote, but your feedback has been recorded.   What does "your feedback has been recorded" mean when casting a vote was declined because of low rep? Does that mean the vote will be displayed only once that account reaches >= 15rep?


How to assign “copy” and “paste” actions to Logitech Anywhere Mouse MX3 on Ubuntu 18.04.5 LTS?

Just purchased the MX Anywhere 3. Works perfectly on the Mac, but I cannot re-assign buttons on my working laptop that has Ubuntu 18.04.5 LTS. I would like to reassign "copy/paste" actions as my current "back/forward" buttons. Any idea how to solve this? Thanks


Why did Slytherin House not get disbanded?

If every former Hogwarts student who goes bad was in Slytherin, why has Hogwarts kept the house over the years? Why not disband it?


I have the following content in in /etc/udev/rules.d/81-external-disk.rules:  ENV{ID_FS_UUID}=="6826692e-79f4-4423-8467-cef4d5e840c5", RUN{program}+="/bin/mount -o nofail,x-systemd.device-timeout=1 -t ext4 -U 6826692e-79f4-4423-8467-cef4d5e840c5 /backup/external"   After running:  udevadm control --reload ; udevadm trigger /dev/sdb1   It does nothing at all. However if II change the mount command for something such as /bin/touch /tmp/xyz it works.  Versions:  [root@helsinki rules.d]# rpm -qa | grep udev libgudev1-219-19.el7_2.12.x86_64 python-pyudev-0.15-7.el7_2.1.noarch [root@helsinki rules.d]# rpm -qa | grep systemd systemd-libs-219-19.el7_2.12.x86_64 systemd-219-19.el7_2.12.x86_64 systemd-sysv-219-19.el7_2.12.x86_64 [root@helsinki rules.d]# cat /etc/redhat-release  CentOS Linux release 7.2.1511 (Core)


How are connections differentiated from behind NAT routers?

Background: I have a very simple server program written in PHP. It's mostly working, but only as long as there is not more than one client per site.   Questions:   How does a NAT Router (typical SOHO router) know which internal client to send returning traffic? What methods might I use to differentiate between multiple clients behind NAT routers?


In a domain, how does one transfer files from one PC to another?

I googled it and all I got was how to transfer files from one domain to another domain.  Say I have two PCs, one running windows server 2008 and the other running Windows 7, they're connected via a LAN, and they're part of the same domain.  How do you send a file from one PC to the other?  Why the heck isn't there some simple function where you right click a file and select send?


How do I protect against injection for 2+ $_POST[variables] in mySQL query?

I have prepared a series of queries which work.  Now I am in the process of securing these queries against injection.  I can do it fine when I have one variable in the query but have not been able to find how to do it for more with trial and error.   This is what I am doing (See $sql and $handle->execute()):  <?php    $sql = "SELECT FORMAT (z.PriceMultiplier * p.BasicTicketPrice,2)  AS totalPrice  FROM Zone z JOIN Production p  WHERE p.Title = :n AND z.Name = :n"; $handle = $conn->prepare($sql);  $zone = "$_POST[Zone]"; $prod = "$_POST[Production]"; $handle->execute(array(":n"=> $zone, $prod))     $conn = null; $res = $handle->fetchAll();      foreach($res as $row) {        echo "<input name='Price' type='text' readonly='readonly' value=£".$row['totalPrice']."><br>";                  }            ?>   How do I assign the variables $zone and $prod to the statement in handle->execute()?  Thank you in advance.  [edit1: SOLUTION: Use ? instead of :n p.Title = ? AND z.Name = ? and just do $handle->execute(array($zone, $prod))]  [edit2: I do not believe this is a duplicate - the question is not how to prevent an injection attack... it is how to deal with multiple variables in doing so.]


Show that $(f_1of_2)(x)=\inf \{f_1(x)+f_2(x):x=x_1+x_2\}$ is convex function

Show that if $f_1(x_1), f_2(x_2)$ are convex functions then , $(f_1of_2)(x)=\inf \{f_1(x)+f_2(x):x=x_1+x_2\}$ is convex function The definition of a convex function  f is that $$f((1-t)x+ty)\le (1-t)f(x)+tf(y)\tag{1}$$ for all vectors $x,y\in \mathbb{R}^n,t \in [0,1]$ so, $(f_1of_2)((1-t)x+ty)=(f_1of_2)\{((1-t)x_1+ty_1)+((1-t)x_2+ty_2)\}$ $=\inf\{((1-t)x_1+ty_1)+((1-t)x_2+ty_2):x=x_1+x_2,y=y_1+y_2\}$ I am just stuck weather I can use Infimum properties or not someone can help ?


I have installed Windows 10 and now I want to install Wubi... Is it possible?


Fixed point of a map $\mathbb R^n \rightarrow \mathbb R^n$

Today I cam across the following exercise:  exercise  Let $\alpha: \mathbb R^n \rightarrow \mathbb R^n$ be a map with $\alpha^p=1$ for some prime $p$. Show that $\alpha$ has a fixed point.  origin  I found the exercise somewhere in my notes. The setting was roughly orientation and the orientation bundle.  approach  For my approach, of course I assumed that $\alpha$ has no fixed point and just as in the Brouwer fixed point theorem I obtained a map $\mathbb R^n \rightarrow \mathbb S^{n-1}$. But now I don't know how to continue. I especially have trouble using the assumption that $\alpha^p=1$.  Any hint or help for this exercise is welcome!  Sincerely Slin  Edit  This indeed is a duplicate of   The answer uses some more advanced theory. I am interested how to do it the way it is suggested in Bredon's "Topology and Geometry". I cannot make the connection between $\mathbb R^n$ and coverings.


Why in the following tables the results of formatting of S columns are different, i.e. dependent on, where the column is in table? Consequently those tables have different width.  \documentclass{article}                \usepackage{siunitx}     \usepackage{array}  \newcommand\mc[1]{\multicolumn{1}{c}{#1}}      \begin{document} \begin{tabular}{c c|                   *{2}{S[table-format=2.2,                        table-space-text-post=\si{\,\%}\ ]<{\,\%}|}                 }     \hline A  &    B       &   \mc{C}  &   \mc{D}  \\  \hline xx & xx xxx     &   12.34   &   56.78   \\  \hline \end{tabular}  \bigskip \begin{tabular}{c|                  *{2}{S[table-format=2.2,                        table-space-text-post=\si{\,\%}\ ]<{\,\%}|}                 c}     \hline A  &   \mc{C}  &   \mc{D}   &    B     \\   \hline xx &   12.34   &   56.78    & xx xxx   \\   \hline \end{tabular}     \end{document}     As you can see, the difference is in the space between numbers and accompanied sign \%. Probably in formatting of D columns I miss something obvious :-(


Dieline- how do I send a dieline to print.

Have a dieline I need printed. Do I send a preserved pdf? Or a full packaged folder?


What does this 'where' mean in this context?

“It is an art where you’ve got to deal with the demands   of every day but at the same time place it strategically   at the heart of what the company is doing.”   — Jeroen   Tas, group CIO of Philips 5   I have problem in where meaning. I think it mean "what".  EDIT:


Setting MACs setting in /etc/ssh/sshd_config on Amazon Linux

We are going through the process of hardening Amazon Linux 1 based on .  Control 5.2.12 states under "Expected Values" :     The following List String value(s) X indicate the current   status of the MACs setting defined within the   /etc/ssh/sshd_config file.      ======Expected Value(s)======   contains regular expression list   hmac-sha2-512-etm@openssh.com   hmac-sha2-256-etm@openssh.com   umac-128-etm@openssh.com   hmac-sha2-512 hmac-sha2-256   umac-128@openssh.com   curve25519-sha256@libssh.org   diffie-hellman-group-exchange-sha256   Based on  RHEL documentation of the setting, we appended the following to /etc/ssh/sshd_config:  MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256    /etc/init.d/sshd restart results in the following error:     Starting sshd: /etc/ssh/sshd_config line 142: Bad SSH2 Mac spec   'hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256'. [FAILED]    How do we configure SSHD MACs on Amazon Linux?


Prove that $\frac{1}{f'(a)} = \frac{1}{2\pi i} \int_C \frac{1}{f(z)-f(a)} dz$

Let $f$ be analytic on an open set $U$, let $a \in U$, and $f'(a)\neq 0$.  Show that  \begin{align*} \frac{1}{f'(a)} = \frac{1}{2\pi i} \int_C \frac{1}{f(z)-f(a)} dz \end{align*} where $C$ is a small circle centered at a.  I thought that this is very similar with Cauchy's integral formula. But, I can't apply the Cauchy's integral formula. How to apply that?   Any help is appreciated..   Thank you!


Centering controls within a form in .NET (Winforms)?

I'm trying to center a fixed size control within a form.  Out of interest, is there a non-idiotic way of doing this? What I really want is something analogous to the text-align css property.  At the moment, I'm setting the padding property of the surrounding form to a suitable size and setting the Dock property of the control to fill.


How do I do a complete DHCP Server Configuration

i am new bie to Linux and wants to configure complete DHCP server and how I can assign ips to clients on Ubuntu or windows machine. will it connect clients automatically to my Linux Ubuntu machine or I may give some configuration.


Prove that $\mathbb{R}^*$ is not isomorphic to $\mathbb{C}^*$.

Prove that $\mathbb{R}^*$, the multiplicative group of non-zero real numbers is not isomorphic to $\mathbb{C}^*$ the multiplicative group of non-zero complex numbers.   I am unsure how to go about this proof. I know in order to be isomorphic, the function must be a bijective homomorphism. In order for the function to be a homomorphism, for $a,b\in\mathbb{R}^*$, $\phi(ab)=\phi(a)\phi(b)$ for multiplicative groups.


How does Google crawler find pages that are not linked to?

Will Google crawler find a page that is not linked to? I.e. pages accessible by manually modifying the URL, like http://www.example.com/node/1/[secret keyword]. Note that it is only secret in that there are no links to it; this "secret" path should't hold sensitive information.