Measure of $\lbrace (x_1,...,x_n) \in \mathbb{R}^n : \sum_{k=1}^{n} x_k \leq 1 \rbrace$

I have to determine the measue of $$\Delta_n=\lbrace (x_1,...,x_n) \in \mathbb{R}^n : \sum_{k=1}^{n} x_k \leq 1, x_k \geq 0, k=1,...,n \rbrace$$ The hint that I have is express $\Delta_n$ in terms of $\Delta_{n-1}$. My attempt was to calculate the case $n = 2$ and $n = 3$, where I got $\frac{1}{2}$ and $\frac{1}{6}$ respectively. From there I could write the measure of $\Delta_n$ as $$\int_{\Delta_{n-1}}dx_{n-1} \cdots dx_1 \int_{x_n=0}^{1- \sum_{k=1}^{n-1}}dx_n$$ and from there integrate step by step. The problem is that I think it is too long a process and I would like to know if there is a faster way to find the measure of $\Delta_n$. Note: I was able to write the previous expression since in the cases $n = 2$ I wrote: $$\int_{x=0}^{1}\int_{y=0}^{1-x}dydx$$ and for the case $n=3$ : $$\int_{x=0}^{1}\int_{y=0}^{1-x}\int_{z=0}^{1-x-y}dzdydx$$


Move tilde (~) on macbook to the § (±) key for Brazilian Portuguese. How do I adjust the keyboard?

Just bought a macbook pro in Dubai with this keyboard layout:    I'm trying to move the tilde symbol to the § key, but I'm not succeeding. Anyone can help?  best,  D


Understand "ibase" and "obase" in case of conversions with bc?

I often use bc utility for converting hex to decimal and vice versa. However, it is always bit trial and error how ibase and obase should be configured. For example here I want to convert hex value C0 to decimal:  $ echo "ibase=F;obase=A;C0" | bc 180 $ echo "ibase=F;obase=10;C0" | bc C0 $ echo "ibase=16;obase=A;C0" | bc 192   What is the logic here? obase(A in my third example) needs to be in the same base as the value which is converted(C0 in my examples) and ibase(16 in my third example) has to be in the base where I am converting to?


Is mod_evasive the best prevention to DDOS attack

I already have IPTables blocking all unnecessary traffic.  Is mod_evasive the best solution for something like this?  What do you use on your server?


If we look at a unit circle we can see that the values of cosine are between -1 and 1 however is there a particular proof for this fact? I have tried using the Eulers identity to arrive at a proof with no luck. I have also tried using the expanded form of cosine : $cos(x)=\sum_{n=0}^{\infty } \frac{(-1)^n x^{2n}}{2n!}$. Using the expansion I tried to manipulate as much as I could however it seems that I am not finding a proof in this fashion either. I also tried going from the fact that it is a cauchy sequence.Any ideas?


The update information is outdated (notification icon)

I am running Ubuntu 14.10 server  I'm getting this icon in the notification bar over the last days, even though Software Center is running updates properly and I have no new updates available.  I have run sudo apt-get update && sudo apt-get upgrade and still have this problem. The output after running sudo apt-get update is:  W: Failed to fetch cdrom://Ubuntu-Server 14.10 _Utopic Unicorn_ - Release i386 (20141022.2)/dists/utopic/main/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs  W: Failed to fetch cdrom://Ubuntu-Server 14.10 _Utopic Unicorn_ - Release i386 (20141022.2)/dists/utopic/restricted/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs  E: Some index files failed to download. They have been ignored, or old ones used instead.   How can I fix this issue?


There is a number of three digits, 1 is never immediate right of 2 is? (A)771 (B) 791 (C) 881 (D)891.  I faced this Question in Aptitude Competitive exam and don't know what the question actually means. Please anyone help me answering this question.


How to bind variable in inline style in LWC?

The code below shows binding of attribute in Lightning component.

   Is there any way to do the same in LWC? In LWC, i tried the below code and then passing "width: xxx%" from js. But it didn't worked.


Using /bin/find /root -name '*.csv' returns:  /root/small_devices.csv /root/locating/located_201606291341.csv /root/locating/located_201606301411.csv /root/locating/g_cache.csv /root/locating/located_201606291747.csv /root/locating/located_201607031511.csv /root/locating/located_201606291746.csv /root/locating/located_201607031510.csv /root/locating/located_201606301412.csv /root/locating/located_201606301415.csv /root/locating/located_201607031512.csv   I don't actually want all the files under /root/locating/, so the expected output is simply /root/small_devices.csv.  Is there an efficient way of using `find' non-recursively?  I'm using CentOS if it matters.


How can I determine the function for summing a series of integers?

I want to sum a series of integers, say from 1 to 5, but I want to generalise this function. I have seen that the function is:  $$ \text{sum} = \frac{n(n+1)}{2} $$  where $n$ is the number to sum up to  So for $n=5$, i.e. $1 + 2 + 3 + 4 + 5$, the sum is $15$.  My question is, how could I (without knowing by heart) work out that function myself?


Is there any sun-color that gives humans "Kryptonian" powers?

Superman famously gets his powers from the light of the yellow sun, and loses them from the light of a red sun.  Is that a purely Kryptonian phenomenon, or does the "color of sunlight" have larger implications throughout the DC universe?  Is there a color of sunlight that would give a human the kind of powers that Superman has on Earth?  If not, is any explanation given (scientific or pseudo-scientific) of why Kryptonians are so profoundly affected by light, unlike other races?


How to check if installing a package will require a reboot?

I often install packages and updates for them, although sometimes it is not convenient to do a reboot if one of the packages needs it, so is there any way of telling BEFORE installing the package/update whether or not it will require you to do a reboot? I have already looked  and the solutions there don't solve my problem, nor the more or less same one described there.


How can I get barcode-scan information into my photo metadata, onsite, untethered?

I need a DSLR camera with a barcode scanner for on-site tours photography, which means it needs to be untethered! The image would have to contain the barcode scanned information in the image metadata or in the name itself.  I've seen solutions like, Foolography and a $2600 Canon Studio Edition launched in 2010. But I'm not sure of either those products!  So I'm asking the gurus here how I can get this working, which camera would I need and any accessory necessary?  I'm trying to recreate something like I saw the on-site volume photographers do in Disney's parks.


I used console commands to have a lot of health, now I can't seem to reset it, I am almost invincible and it takes the fun out of the game please help


What are these green checkmarks on my Desktop icons?

I was playing the solitaire they added back in Windows 10 and when I closed it I noticed there were these green checkmarks on my Desktop icons:    What are these green checkmarks on my desktop? How do I get rid of them?


I thought that the droid from Star Wars Rebels spoke in binary, but somehow Hera and Ezra are able to understand and interpret for it. It made sense for C3PO to understand R2 because they're both machines, and I always thought when a human character understood R2 it was because they had a console in front of them (I could be wrong, but I don't remember any instances where this wasn't the case). This doesn't seem to be the case for Chopper though. So, is Chopper not speaking in a binary encoding? Or is it somehow possible for humans to interpret binary in the Star Wars Universe?


Which model is better, one just before overfitting with higher accuracy or one with no overfitting and lower accuracy?

I am training a CNN model. In the first one I got a training accuracy of 87%(0.29 loss) and validation accuracy of 87%(0.30 loss) at 5th epoch, I kept training it for total of 15 epochs and as expected it started overfitting with training accuracy increasing to 97%(0.01 loss) and validation remaining at 87%(0.35 loss). In the second model, I used Data Augmentation and Dropout layer to deal with overfitting (trained for total 10 epochs). These are the results : 5th Epoch : Train Accuracy 77% (0.45 loss) and Validation accuracy 77% (0.41 loss). 10th Epoch : Train Accuracy 82% (0.38 loss) and Validation accuracy 82% (0.35 loss) From the loss and accuracy graph which you can see below, it's clear that Model is overfitting in first scenario, but in second it's not overfitting. Scenario One  Scenario Two  My question is, which model is better in real world based on accuracy ? Model one stopped at epoch 5 with 87% accuracy or model 2 which has not overfit with 82% accuracy (validation)? I understand just based on accuracy model 1 sounds better but it's ultimately overfitting, but if I stop the training using early stopping or something similar, will this be a better model than my second one ?


What crimes can you get away with as thane?

I just became thane in Whiterun and was wondering, What crimes can you get away with as thane, and how many times can you use your rank as an excuse for crime?


How to make colored backgrounds not influence the color of an object

I am making an animation with a green background. When a lamp shines on my mesh, the background somehow makes the lamp shine on my mesh green as if the lamp was shining on it through green glass. How do I make this not happen? My mesh is opaque, has a diffuse BSDF, and is white. Thanks in advance.


Linear Regression: Consequences of Violating Assumptions?

I've been reading more about linear regression and the assumptions it makes.  What are the consequences of violating some of the assumptions involved?  For instance, you need the dataset to exhibit little or no multicollinearity.  What happens if I ignore this?  For instance, suppose I have a dataset where x_3 and x_4 are just duplicates of each other (and thus perfectly correlated).  The only difference I can see is that, instead of having one line of best fit, I can now have infinite:  E.g. if the line of best fit without x_4 had Bx_3 in it, then I can just distribute B amongst x_3 and x_4.  So if B = 5, I could do 4x_3 + x_4 or 3.5x_3 + 1.5x_4, etc.  So, it seems like:  1) Maybe it's not disastrous to violate the multicollinearity assumption?  2) Is it much worse to violate the others / if so, what are the consequences of doing so?  Thanks!


Is there a maximum player level in Pokemon Go?  I'm used to playing Ingress, where there was a maximum level of 8 initially (and then 16.) Does Pokemon GO have a similar mechanic in this regard, or does it work differently?


Xlib: extension "GLX" missing on display ":0". and OpenGL GLX extension not supported by display ':0'

I am trying to use OpenGL on my Ubuntu 12.04 LTS. I installed OpenGL with the following commands:  sudo apt-get install g++ cmake sudo apt-get install freeglut3 freeglut3-dev sudo apt-get install binutils-gold   I wrote a simple example in C++ and compiled it with g++ -lGL -lglut main.cpp -o test and then I tested it using ./test. A window opened but it was black and I didn't show anything.  So, I installed my nvidia driver using the following commands:  sudo apt-add-repository ppa:ubuntu-x-swat/x-updates sudo apt-get update sudo apt-get upgrade sudo apt-get install nvidia-current sudo apt-get install nvidia-settings sudo reboot   And now when I try to run again the program it gives me the 2 errors:  Xlib:  extension "GLX" missing on display ":0". freeglut (./test): OpenGL GLX extension not supported by display ':0'   What could be the problem?  Also, here is the output of the lspci | grep VGA command:  00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) 01:00.0 VGA compatible controller: NVIDIA Corporation GF108M [GeForce GT 525M] (rev a1)


How to make selected an option of tag select in jquery without value

I need to make selected option 17 using JQuery I can't use value, because it's always different. So is there any solution to use number of 'select' child or somthing? Thank you.  <select name="size" id="size">     <option value="1430">17</option>     <option value="1429">19</option>     <option value="1428">20</option>     <option value="1427">16</option>     <option value="1426">15</option>     <option value="1425">18</option> </select>


Can a small sample be cause of heteroscedascity? My guess is that it doesn't depends only on sample size, but also on sample bias or measurement error.


Proving $\int_{0}^{\infty} \mathrm{e}^{-x^2} dx = \frac{\sqrt \pi}{2}$

How to prove  $$\int_{0}^{\infty} \mathrm{e}^{-x^2}\, dx = \frac{\sqrt \pi}{2}$$


Warn users before their account is suspended

Questions  are fairly common.  New users sign up, treat Stack Overflow like a forum, and wind up with a suspended account.  They then post here for help, and a moderator ends up writing the same explanation that was written the last time this came up.  Can we do a better job about warning users that their behavior is starting them on the path toward ?  After, say, their first two posts are flagged and deleted can we throw up a red warning banner at the top, linking to a page describing what kinds of posts are acceptable (and unacceptable) here, and warning that they're on the verge of being suspended?    Similar to   and probably a duplicate of


Cannot follow locked posts; wrong error message when attempting to do so

I just visited the question here, which is locked as a "community effort":    I (legitimately) wanted to "Follow" the question so that I would be notified if the status of those types of questions changed in the future.  When I press the "Follow" button, it appears to work. But then I notice a banner at the top of the page:     This post has been locked; locked posts can't be voted on     When I refresh the page, it's clear that the "Follow" action did not work.  Something's clearly wrong here. Ideally I would be able to follow the question. If not, the action button should not be available. And if I can click the button, it should show the correct error message.


C41 (color negative) processing is . I'd still like to learn about film processing, and have heard that black and white negatives are fairly straightforward.  How do I develop black and white negatives at home? What chemicals and equipment will I need?


I have seen the post here:  It is now possible to tag faces that have been detected, but not recognized. However, sometimes a face isn't even detected. Is there any way to fix this? Or is there any alternative to photos that offers similar features, and also this?


Those of us who have been using SO (or any SE site for that matter) for a while know that the box where we type our text is not identical to what is posted (because of various markdown capabilities we are given). We also know that there is a display below the text box that shows us what our post will actually look like once we are done, and we know how to format thing the way we would like them to look.  I've noticed a trend where a user will format things nicely (or somewhat nicely) as plaintext where they type, and ignore the fact that it is not at all formatted like that in the actual post (despite the fact that it is displayed, live, directly below where they are typing). Lists that are meant to span several lines appear as a single string across one line running onto several, code is partially code-formatted, etc...  I suggest that new users and users with many third-party edits (corrections by more experienced users), be prseented with a confirmation dialog when posting confirming that they have, in fact, checked out how their post will actually appear once posted, and that it is accurate. To address concerns regarding reduced conversions, a possible solution would be to bypass the dialog for absolute first posts, since those will be in First Post review queue anyway.  This will:   Make it easier for everyone to read Reduce the amount of editing we have to do to make things readable Make it easier to take new, serious posters seriously, as their questions won't look lazy and effortless due to lack of formatting.   Mock up of dialog to be displayed:   Possible criteria for whether to display dialog:  if posts == 0:     False if posts < 5:  # questions AND answers     True if third_party_edits / posts > .3: # 30% "fixed" by others     True


I am new to LaTeX, cant figure out this issue. I want a box around the following equation.   \begin{equation} A  State  S_{t}   is  Markov if and only  if  : \newline P [ S_{t+1}  |  S_{t} ] = P [  S_{t+1}   |  S_{1}.......S_{t} ] \end{equation}   The \newline has no effect. Some solutions say use boxed, fbox etc. but then I cannot use newline inside it gives me an error. If I use fbox the frame is too big, I just need a nice looking frame (like what boxed gives you), but I also want to use \newline in it.    Edit : I could not achieve exactly what the title says but I got what I wanted using the following lines.   \newcommand*\widebox[1]{\fbox{\hspace{1em}#1\hspace{1em}}} \begin{empheq}[box=\widebox]{align} \nonumber\\ A \ State \ S_{t} \  is \ Markov \ if \ and \ only \ if \ :\\ P\ [\ S_{t+1}\  |\  S_{t}\ ] = P [ \ S_{t+1} \  | \  S_{1}.......S_{t} \  ]\nonumber\\ \nonumber \end{empheq}


Hard time interpreting r output, p value confusion?

I think I'm overthinking it, but this p-value for the exp.c:anx.c interaction (3.84e-09) is significant, right? In other words, it's much smaller than 0.001? Irrational numbers are confusing for me, and I also have a negative t-value that is throwing me off.   I'm also confused at the bottom where it shows: p-value: < 2.2e-16, what does this mean? Overall for the model?


Why is find not listing matching files when preceded by an asterisk(*)?

On Ubuntu 14.04, 64 bit, I have set /lib/modules/4.2.0-27-generic/kernel/drivers to be my current directory. I intend to search all files having net present as a sub-string. If I search with a regex of *net*, only the ./net directory is returned as the search result. However, if I specify exact file name, then only it lists out the relevant file (Useless because not always I know the exact file name to cross check).  $ find . -name *net*  ./net $ find . -name *usbnet*  ./net/usb/usbnet.ko $ pwd /lib/modules/4.2.0-27-generic/kernel/drivers   What mistake am I making?


What are valid values for the id attribute in HTML?

When creating the id attributes for HTML elements, what rules are there for the value?


Does the Biot Savart law only hold for magnetostatics?

I am wondering if a time dependent magnetic field due to a time varying current can be calculated with the Biot Savart law, even though a time varying current is produced by a time varying electric field.


So you are holding a thin horizontal rod (which is not bendable) which is fairly heavy and there is a heavy object (lets say a bag full of heavy stuffs) hanging from it. So now if the bag is shifted towards the end at which you are holding the rod, it seems that we are putting the same amount of force in the upward direction as the rod-bag system is putting in the downward direction. But here comes the catch: When the bag is shifted to the opposite end, opposite to which we are holding the rod, it feels like more force is needed in the upward direction to keep the forces on the rods balanced. WHY SO?


Help with 301 redirect from subdomain to root domain

I need to forward existing subdomain links to the root domain as the subdomain no longer exists. I have tried so many different lines of code in my .htaccess file and can not get the redirect to work.  The links to the subdomain look like: http://sub.example.com/dir/y99bb4  Can anyone suggest any code for me?


I'm thinking of buying this computer and doing a dual boot with Linux and Windows 8. In all of the forums that I have read I found out that its hard to do. If anyone can please tell how to install Ubuntu on Lenovo Y410P I would greatly appreciate it.


A word to describe the feeling that you are forgetting something?

Is there a word (or short phrase) that describes the sinking feeling that one is forgetting something, but but doesn't know what the "something" is?  For example, I'm looking for a word that describes the following feeling: Leaving to go on holiday, and two hours into your journey you feel sure you have left something important at home but just can't think what it is.


Install Ubuntu Linux Desktop 15.x on Pre-installed Windows 8.1 laptop and have dual boot

I looked at various questions all over the internet. Infact i did the same almost 6 months back on my HP Desktop but i did so much hit and trial that i have forgotten what to do this time? Do i need to do any or all of them or what specifically? Disable Secure Boot in BIOS? Disable quick start within Windows 8.1? Disable UEFI Boot and enable legacy boot?  What all i need to do? On top of it, i have no idea what needs to be done exactly? There are so many blogs and stuff on internet forums with a very confusing answers.


How to sort a list of strings (names) alphabetical in javascript

I have a list of names (i.e strings) from user input, and I would like to sort them in alphabetic order


What is the rule for duplicating the last letter when adding "-ed"?

I wonder if there is any rule for doubling the p at the end of a stem. For example:     stop — stopped   but      help — helped


how to apply separately online for tourist visa for UK for a family (Husband, Wife and Child)?

I want to apply for tourist visa for UK along with my wife and son.  I am told that separate applications for each member be filed.  I used my email ID to complete my application.  Now I want to apply on behalf of my wife and son.  Should I use another email ID ?


Should the amount of possible edit suggestions per day be limited?

As a reviewer :     User is editing too much post today. Obviously not interested in content but in reputation   Not exactly a valid rejection reason in general, but , and while a few were ok, many merely placed keywords in backticks (which btw should not be done for non-code, e.g. for the reasons listed ) and should have been rejected (a shockingly large amount of these were however approved). This suggestion behaviour is most certainly not what the system is intended for, so I wonder if there is a limit on suggestions in place? Note I'm not referring to the   but to a general limit of, say, 20 suggestions per day.  As many of you have noted, reviewers actually accepting such crappy suggestions are a problem. But they are not the problem, but rather a consequence. Limiting the amount of edit suggestions1 limits the source of all evil bad edits, while the serious reviewers are rather the victims who loose the battle against are slower than robo-reviewers and thus more likely to reject a suggestion when it has already been approved. We should educate the editors to "make it count", which to my knowledge is already the desired behaviour, but not in a vague "minimum character count" - one missing backtick edited in may severely improve a post, while a second one to emphasize a non-code keyword is bad.    1 And as discussed in comments, 20/day is not necessarily a good measure, something like max. 5 unapproved edits in the last 24 hours where approval a) make another edit available and b) increases that limit with time might be better - the suggestion here is about the consideration of such a limit, not about its implementation details


CTRL+SHIFT+??? also changes language, when just CTRL+SHIFT should do it

Just moved from Unity to GNOME and faced such problem: I change keyboard layouts by Ctrl+Shift. Often use console and when I press Ctrl+Shift+C/V (or any other combinations, where there are Ctrl and Shift), GNOME also changes keyboard layout language.  In Unity, and in Windows, the computer normally waits whether I add to the combination any additional keys or release at least one of the keys (Ctrl/Shift) in order to change the language. GNOME, in my case, changes the language immediately once Ctrl+Shift are pressed.  I have Ubuntu GNOME 16.04, x64 (Fresh installation, downloaded from )  Can anyone suggest how to fix this?


After a reboot, my NFS drives do not mount automatically, I need to manually do:  sudo mount -a  What is wrong? My /etc/fstab looks like this:  /dev/disk/by-uuid/b59667cf-c443-4832-9286-0856ca9e7a35 / ext4 defaults 0 0 /swap.img       none    swap    sw      0       0  192.168.1.96:/nfs/Backups /media/iomega nfs nolock 0 0 192.168.1.96:/nfs /media/ix2-6 nfs nolock 0 0 192.168.1.97:/nfs /media/ix2-4 nfs nolock 0 0 192.168.1.97:/nfs/Videos /media/ix2-4-videos nfs nolock 0 0 192.168.1.97:/nfs/Documents/Archives /media/ix2-4-archives nfs nolock 0 0 192.168.1.92:/nfs/Videos /media/wd-ex2/videos nfs nolock 0 0 192.168.1.92:/nfs/Documents /media/wd-ex2/Documents nfs nolock 0 0 192.168.1.92:/nfs/Sounds /media/wd-ex2/Sounds nfs nolock 0 0 192.168.1.92:/nfs/USB_TrekStor_DS_maxi_g.u_q_1 /media/wd-ex2/usb1 nfs nolock 0 0


What should I make my computer do while I'm away from keyboard?

During the day, usually I'm away from my computer for 3-5 hours. I also sleep 6+ hours every night.  I run Arch Linux x64 on my computer.  Besides the usual things that do not require user intervention (torrenting, backing up data, upgrading the system, etc...), is there anything useful that I can let my computer do while I'm away?  Considering I almost never turn the computer off, it seems like a waste it's sitting there doing nothing. I'm looking for any kind of suggestion, not only machine maintenance.


Algorithm for computing Hadamard product of two rational generating functions

If I have two generating functions $A(x) = \sum_na_nx^n$ and $B(x) = \sum_n b_nx^n$   then the Hadamard product is $(A \star B)(x) = \sum_{n} a_nb_nx^n$.  Now when $A$ and $B$ are both rational functions ($P(x)/Q(x)$ with polynomials $P, Q$) I've seen non-constructive proofs that $A \star B$ is also rational.  Given two rational generating functions $A$, $B$, is there an algorithm that efficiently computes $A \star B$? Or at least a constructive proof you could use to write an algorithm?


Java - Object state does not change after method call

Beginner java question, but I cannot understand how call-by-Value ( or Reference ) is working in the example below -   How come the String value is not modified after it exits the method while my custom String Object is. ? Same with other classes like Date..  public class StringMadness {  public static void main(String[] args) {     String s = "Native String";     CustomStringObject cs = new CustomStringObject();     System.out.println("Custom String Before: " + cs.str);     hello(cs);     System.out.println("Custom String After: " + cs.str);      System.out.println("Native String Before: " + s);     hello(s);     System.out.println("Native String After: " + s); }  private static void hello(String t) {     t = "hello " + t; }  private static void hello(CustomStringObject o) {     o.str = "hello " + o.str;   } }  class CustomStringObject {  String str = "Custom String"; }


Say for example I take a 30 year mortgage and I make repayments fortnightly. How many repayments will I be making, will it be exactly 780? If so, how does one account for the extra days?


Prove ${n - 1 \choose k - 1} + {n - 2 \choose k - 1} + {n - 3 \choose k - 1} + \dots + {k - 1 \choose k - 1} = {n \choose k}$

Can someone check my logic here.   Question: How many ways are there to choose a an $k$ person committee from a group of $n$ people?   Answer 1: there are ${n \choose k}$ ways.   Answer 2: condition on eligibility. Assume the creator of the committee is already in the committee. This leaves us with choosing $k - 1$ people from a group of $n - 1$ potentially eligible people. If all remaining people are eligible, there are ${n - 1 \choose k - 1}$ possible committees, if there are $n - 2$ eligible people, there are ${n - 2 \choose k - 1}$ committees, if there are $n - 3$ eligible people, there are ${n - 3 \choose k - 1}$ committees,..., if there are $k - 1$ eligible people there are ${k - 1 \choose k - 1}$ committees. Therefore,$${n - 1 \choose k - 1} + {n - 2 \choose k - 1} + {n - 3 \choose k - 1} + \dots + {k - 1 \choose k - 1} = {n \choose k}$$.


Python regex not working when flags are passed as positional arguments in re.sub

So, here's my question:  I'm trying to replace anything in a string that is not an "A" or a "C" case insensitively. My strings are all three characters. (In reality the specific two letters will change, which is why I'm not hardcoding the negated values.)  So, I thought I'll do  re.sub(r'[ac]', "X", "ABC", re.IGNORECASE)   But, what I got back was 'XXC'. I expected 'AXC'.  The full range of my data would be  map(lambda s: re.sub(r'[^ac]', "X", s, re.IGNORECASE), [ "ABC", "ABc", "AbC", "Abc", "aBC", "aBc", "abC", "abc" ])   and what I get back is this:  ['XXC', 'XXc', 'XXC', 'XXc', 'aXX', 'aXc', 'aXX', 'aXc']   Why does the re.IGNORECASE replace the "A"'s? and, why does it sometimes replace the C's? (Notice how it turned "abC" to "aXX".  if I do this:  map(lambda s: re.sub(r'[^acAC]', "X", s), [ "ABC", "ABc", "AbC", "Abc", "aBC", "aBc", "abC", "abc" ])   I get what I want:  ['AXC', 'AXc', 'AXC', 'AXc', 'aXC', 'aXc', 'aXC', 'aXc']   Must I use r'[^acAC]'?? Is there no way to case insensitively complement a regex?  It's interesting to me also, that in vim, if I put all those strings into a text file and do     :%s/[^ac]/X/gi   I get the right thing. (And, blasphemous as this might be, if I do this in perl:       #! /usr/bin/perl      use strict;      foreach my $gene ( "ABC", "ABc", "AbC", "Abc", "aBC", "aBc", "abC", "abc") {                 my $replaced = $gene;             $replaced =~ s/[^ac]/X/gi;             printf("%s\n", $replaced);     }   I get   AXC AXc AXC AXc aXC aXc aXC aXc   So does Ruby:  irb(main):001:0> ["ABC", "ABc", "AbC", "Abc", "aBC", "aBc", "abC", "abc"].collect{|s| s.gsub(/[^ac]/i,"X") } => ["AXC", "AXc", "AXC", "AXc", "aXC", "aXc", "aXC", "aXc"]   How can I do the equivalent in python without doing r'[^acAC]'?  Thanks!


What's the /home directory for, or did I just accidentally create it?

I saw reference to a bash command, cd /home, in a multiple choice quiz about navigating within Terminal. I tried it, expecting -bash: cd: /home: No such file or directory, but to my surprise it took me to a top level directory /home. I don't know if it just created the directory or if it was already there, or if it's a temporary thing or what.  I've googled around for info on the hidden top level directories (/var, /usr, /private, /etc, ...) but none mention a /home directory. Using ls -al from / yields (omitting all but the relevant line):  dr-xr-xr-x   2 root  wheel        1 Sep  6 15:57 home   and a ls -al from within /home yields  total 2 dr-xr-xr-x   2 root  wheel     1 Sep  6 15:57 . drwxr-xr-x  30 root  wheel  1088 Aug 17 17:17 ..   I was surprised at how hard it was to track down a comprehensive (or even partial) directory tree showing what/where stuff is (beyond what shows up in Finder).  Can anyone help me out?


please see my alternative question below. :)    I'm currently working on a bst file for a multivolume companion (approx. 1800 pages in total). By using makebst, I tried to apply the guidelines that my publisher gave to me. Yet, the resulting bst file is not satisfying all my needs.  These are the guidelines:     Monographs:   Alpha, B. (edition numberyear). book title. publisher.   Gamma, D./Epsilon, Z. (eds., year).  booktitle. publisher.   Articles:   Iota, K. (year). article title, journal name volume: pages.   Articles in companions:   Ny, L. (year). article title, "in:" E. Ditor (ed., year), book title. publisher. pages.   I have already inserted the "ed., "/"eds., " before the year. Now I'm struggling with the edition number that should be superscripted right in front of the year. There ist still a ", " before the edition number. Also, it should appear in the in-text citation (e.g., "Alpha (edition numberyear, page)").  I would appreciate if some of you could have a look at the bst file. And maybe tell me how to get rid of the extra ", ", and how to add the edition number to the in-text citation.    I bet my problems are way easier to fix with biblatex. I have already customized a bbx file, that satisfyies the guidelines from above. But, the publisher wants to diferent in-text citation styles:     in-text citation: Alpha (edition numberyear, page)   footnote citation: Alpha (edition numberyear) page   At the moment (as I'm using bibtex with natbib), I modified the \footnote command to set a boolean variable to true. This way, my modified \citet command checks if the citation is inside the normal text or a footnote. (I exspect this to end up in a much higher compilation time due to setting the boolean variavble to true and false at each \footnote and to check the variable at each \citet.) This modification is not perfect yet. (Cf. \citet{Alpha:2002} => "Alpha (2002, )")  Thank you so much or your help. rsa-krypto    bst-test.tex:  \documentclass{scrartcl} \usepackage[utf8]{inputenc} \usepackage[]{natbib}     \bibpunct[:\ ]{(}{)}{;}{a}{}{;}  \let\svfootnote\footnote \renewcommand{\footnote}[2][\thefootnote]{%     \stepcounter{footnote}%     \gdef\infootnote{T}%     \svfootnote[#1]{#2\gdef\infootnote{F}}% } \gdef\infootnote{F}  \makeatletter \newcommand{\citefoot}[2][]{%     \@ifnextchar[%     {\citeauthor{#2} (\citeyear{#2})}%  w     {\citeauthor{#2} (\citeyear{#2}) #1}%   w/o } \newcommand{\citetxt}[2][]{%     \@ifnextchar[%     {\citeauthor{#2} (\citeyear{#2})}%  w     {\citeauthor{#2} (\citeyear{#2}, #1)}%  w/o } \renewcommand{\citet}[2][]{%     \if T\infootnote%         \citefoot[#1]{#2}%     \else%         \citetxt[#1]{#2}%     \fi% } \makeatother  \begin{document}     Dies ist ein Testdokument zum Prüfen der bst-Datei.      \infootnote      \footnote{Cf. \citet[12]{Alpha:2002}.}      \citet{Alpha:2002};     \citet[13]{Gamma:2015};     \citet[14]{Iota:1998};     \citet[15]{Ny:2018}      \bibliographystyle{test-companion}     \bibliography{test-companion} \end{document}   test-companion.bib:  @book{Alpha:2002,     Author = {Beta Alpha},     Note = {(= optional note)},     Publisher = {Chicago},     Title = {Book title},     Year = {2002},     edition = {2}}  @book{Gamma:2015,     editor = {Delta Gamma and Zeta Epsilon},     Publisher = {Berlin},     Title = {Another book},     Year = {2015}}  @article{Iota:1998,     Author = {Kappa Iota},     Journal = {journal name},     Volume = {24},     Pages = {11--18},     Title = {article title},     Year = {1998}}  @incollection{Ny:2018,     Author = {Lambda Ny},     Booktitle = {book title},     Editor = {E. Ditor},     Pages = {93--129},     Publisher = {London},     Title = {article title},     Year = {2018}}   EDIT: test-companion.bst   EDIT2: babelbst.tex


I have installed Ubuntu 18.04 on a cloud server and accessed it with a VNC client. I tried installing software using the software center, but got an error that I do not have permission to install software. How do I enable those permissions?


Using StringBuilder with double brace initialization

double brace initialization is good for have better visibility of the context of java code.  unfortunately StringBuilder can't use with double brace initialization like      final String[] array = new String[] {"A", "B"};     System.out.println(new StringBuilder(){{                            for (String s : array){                                append(s + "\n");                            }                        }}.toString());   is this a good alternative? any better suggestions? my intention for this question is not to find a way for string concatination. my intention is to find a way for use double brace with StringBuilder.      final String[] array = new String[] {"A", "B"};     System.out.println(new Object(){         @Override public String toString(){             StringBuilder stringBuilder = new StringBuilder();             for (String s : array){                 stringBuilder.append(s + "\n");             }             return stringBuilder.toString();         }     });


Measure the correlation between categorical variable and continuous variable

Question I would like to see how the machine learning algorithms (models) used in a paper could affect the citation count the paper receives (suppose all papers considered are published at about the same time). More specifically, I have a dataset that looks like following id model citation count   1  SVM             10   2 LSTM              5   3 GBDT              0   4  HMM              2   5  SVM              4 ...  them is it possible to see how the third column is influenced by the second column? There are two naive thoughts  Encode the model name with 1, 2, 3, etc, and use Pearson correlation. Plot the distribution of model name count and citation count respectively, and measure the difference of two distributions using JS divergence or KS divergence. However, in my example, "SVM" will have a high model name count and therefore higher citation count, then the result might not make sense.  Could someone provide pointers to my problem? Thank you in advance!


Criteria for the difference of two matrices to be positive semidefinite when the eigenvectors are known

Let $A$ be a rank 1 positive semidefinite matrix and $B$ a Hermitian matrix. Suppose I know the eigenvectors of both $A$ and $B$ and that $A-B$ is also positive semidefinite.  Apart from Weyl's inequality is there anything that can be deduced about the eigenvalues of $B$?


I have to pick a ball from a set of balls. Each ball has a size, so I have a distribution for ball sizes (I assume a number between 0-1).   I want to pick a new ball at each step with the probability associated with its size. I have read about . But I wasn't able to find any numerical example. All I could find were some well known distributions, that are always reversible, however in my example two or more balls can have the same size. I'm not able to understand how to move forward.  Any help is greatly appreciated.


Besides all the talk about the "Philosopher's Stone". Can anybody or anything become an alchemist? Not including homunculus.


$\displaystyle\frac{n!}{(n-k)!~n^k}\to 1$ as $n\to\infty$

In proving the equivalence of the series and $\lim_{n\to\infty}(1+\frac{x}{n})^n$ definitions of $e^x$, it turns out that I need to show that for any positive integer $k$, $$\lim_{n\to\infty}\frac{n!}{(n-k)!~n^k}=1.$$ I have no idea how to show this (I'm a Physics student). Any help?


How to alter my JLabel based on input from a separate class

Im working on creating a basic GUI for a program I was tasked with early on in the year. My goal is to have it so that when the program is executed, the first screen that displays is a field for the user to type out their name. Upon pressing enter or the submit button this then directs them to another window which will have the name of the player embedded as a layer.   Now I'm not sure I am doing this in the most efficient way but from reading through multiple answers, creating separate frames seems like the best way to do this, although do correct me if I am wrong.  I get the following error when I execute      "Exception in thread "AWT-EventQueue-0"   java.lang.NullPointerException"   So I begin by running the loginpanel code:  import java.awt.event.ActionEvent; import java.awt.event.ActionListener;  import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JPanel; import javax.swing.JTextField;  public class loginPanel extends JFrame {      public static void main(String[] args) {         loginPanel loginFrame = new loginPanel();     }      private JButton submit;     private JLabel playerName;     private JTextField nameInput;     public String name;      JPanel panel = new JPanel();      loginPanel() {         setTitle("Game Data");         setSize(300, 400);         setLocationRelativeTo(null);          submit = new JButton("Submit");         submit.addActionListener(new ActionListener() {             public void actionPerformed(ActionEvent event) {                  if (nameInput.getText().isEmpty()) {                     JOptionPane.showMessageDialog(null, "Invalid Input, please try again");                 }                  else {                     name = nameInput.getText();                     gameDataPanel mainFrame = new gameDataPanel();                     mainFrame.setVisible(true);                     dispose();                 }             }          });          playerName = new JLabel("Enter Player Name");          nameInput = new JTextField(30);         nameInput.addActionListener(new ActionListener() {             public void actionPerformed(ActionEvent event) {                  if (nameInput.getText().isEmpty()) {                     JOptionPane.showMessageDialog(null, "Invalid Input, please try again");                 }                  else {                     name = nameInput.getText();                      gameDataPanel mainFrame = new gameDataPanel();                     mainFrame.setVisible(true);                     dispose();                 }             }          });          panel.add(playerName);         panel.add(nameInput);         panel.add(submit);          getContentPane().add(panel);         pack();         setVisible(true);         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     }      public String grabName() {         return nameInput.getText();     }  }   and then it should run this upon pressing submit:  import java.awt.Color; import java.awt.Dimension;  import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JTextField;  public class gameDataPanel extends JFrame {      private JLabel playerName, gameName, gameScore, timePlayed;     private JTextField gameNameField, gameScoreField, timePlayedField;     private loginPanel login;     private String name2;      public static void main(String[] args) {         gameDataPanel mainFrame = new gameDataPanel();     }      JPanel panel = new JPanel();      gameDataPanel() {         setTitle("Game Data Entry Program");         setBackground(Color.WHITE);         setPreferredSize(new Dimension(400, 300));           name2 = login.name;          playerName.setText(name2);          panel.add(playerName);         getContentPane().add(panel);         pack();         setVisible(true);         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     }  }   The problem is that it never gets past the first screen, any help is appreciated. Thanks!


Why Li is not added as contact by ion implantation method in p type HPGe detector?

n+ contact of p type Ge is ~700µm thick compared to p+ contact of n type Ge only ~0.3µm. The process of adding the contact is different. n+ contact Li is added by diffusion process but p+ contact B is added by ion implantation technique. In diffusion we can get only thick contact but in ion implantation we can achieve thin contact, Fine. With a thin (~0.3µm) Li ion implantation, low energy efficiency of p type HPGe detector can be on par with n type HPGe detector (as per the attached fig).    Why Li is also not added as contact by ion implantation method? Is it a mandatory requirement of having thick (~700µm) n+ contact or only due to technology used for doping, we are getting thick (~700µm) contact?


Is a quotient group a subgroup?   I am trying to solve the question below, and if the answer to above is "yes," then my proof will follow below.   I am trying to prove that a cyclic group G, has a cyclic quotient group G/N.  Where N is a normal subgroup.  A SUBGROUP OF A CYCLIC GROUP IS CYCLIC.  By   So if   (1) G is cyclic   (2) G/N is a subgroup   (3) G/N is a cyclic subgroup   (4) The Quotient group G/N is cyclic   I am unsure about my reasoning in step (2), Is this a valid assumption?


Does the rotation of the earth dramatically affect airplane flight time?

Say I'm flying from Sydney, to Los Angeles (S2LA), back to Sydney (LA2S).  During S2LA, travelling with the rotation of the earth, would the flight time be longer than LA2S on account of Los Angeles turning/moving away from our position?  Or, in the opposite direction, would the flight to Sydney be faster since the Earth turns underneath us and moves Sydney closer?  ===   Please ignore jet stream effects and all other variables; this is a control case in an ideal environment. By "dramatically" I suppose I mean a delay of 1 hour or more.


"I can't find file `pgfutil-common-lists.tex'." after update

I've just did an update.   $ sudo tlmgr update --self tlmgr: package repository http://sunsite.informatik.rwth-aachen.de/ftp/pub/mirror/ctan/systems/texlive/tlnet tlmgr: saving backups to /usr/local/texlive/2013/tlpkg/backups tlmgr: no updates for tlmgr present. tlmgr: no updates available $ sudo tlmgr update --all [...] [108/109, 06:49/06:49] update: collection-pictures [1k] (32769 -> 33307) ... done [109/109, 06:51/06:51] update: collection-publishers [1k] (32864 -> 33330) ... done tlmgr: package log updated: /usr/local/texlive/2013/texmf-var/web2c/tlmgr.log running mktexlsr ...  mktexlsr failed (status -1), output:  running mtxrun --generate ...  mtxrun --generate failed (status -1), output:  Can't exec "kpsewhich": No such file or directory at ./tlmgr line 679. Use of uninitialized value $TEXMFSYSVAR in scalar chomp at ./tlmgr line 679. Can't exec "kpsewhich": No such file or directory at ./tlmgr line 680. Use of uninitialized value $TEXMFSYSCONFIG in scalar chomp at ./tlmgr line 680. Can't exec "kpsewhich": No such file or directory at ./tlmgr line 681. Use of uninitialized value $TEXMFLOCAL in scalar chomp at ./tlmgr line 681. Can't exec "kpsewhich": No such file or directory at ./tlmgr line 682. Use of uninitialized value $TEXMFDIST in scalar chomp at ./tlmgr line 682. Use of uninitialized value $TEXMFDIST in concatenation (.) or string at ./tlmgr line 693. Can't exec "kpsewhich": No such file or directory at /usr/local/texlive/2013/tlpkg/TeXLive/TLUtils.pm line 2785. Use of uninitialized value $tmfsysconf in scalar chomp at /usr/local/texlive/2013/tlpkg/TeXLive/TLUtils.pm line 2785. Use of uninitialized value $tmfsysconf in concatenation (.) or string at /usr/local/texlive/2013/tlpkg/TeXLive/TLUtils.pm line 2786. Cannot open /web2c/updmap.cfg for writing: No such file or directory at /usr/local/texlive/2013/tlpkg/TeXLive/TLUtils.pm line 2928.   Then I run mtxrun --generate which seemed to work.  Then I've tried to compile  and got:  (/usr/local/texlive/2013/texmf-dist/tex/generic/pgfplots/pgfplots.revision.tex) (/usr/local/texlive/2013/texmf-dist/tex/latex/pgf/frontendlayer/tikz.sty (/usr/local/texlive/2013/texmf-dist/tex/latex/pgf/basiclayer/pgf.sty (/usr/local/texlive/2013/texmf-dist/tex/latex/pgf/utilities/pgfrcs.sty (/usr/local/texlive/2013/texmf-dist/tex/generic/pgf/utilities/pgfutil-common.te x ! I can't find file `pgfutil-common-lists.tex'. l.556 \input pgfutil-common-lists.tex  (Press Enter to retry, or Control-D to exit) Please type another input file name:   When I enter /usr/local/texlive/2013/texmf-dist/tex/generic/pgf/utilities/pgfutil-common-lists.tex it seems to work until it gets to pgfmathfunctions.integerarithmetics.code.tex which it also doesn't find.  As  with the same problem had problems with the path, I checked it (added breaks to make it easier to read):  $ echo $PATH /usr/local/texlive/2013/bin/x86_64-linux: /usr/local/texlive/2013/bin/x86_64-linux: /usr/local/texlive/2013/bin/x86_64-linux: /usr/local/texlive/2013/bin/x86_64-linux: /usr/local/texlive/2013/bin/x86_64-linux: /usr/local/sbin:/usr/local/bin: /usr/sbin:/usr/bin:/sbin:/bin:/usr/games: /usr/local/games   I don't know why TexLive is there 5 times, but that should not be a problem (?)  Before the update, I had pgfplot 1.09.  Can anybody please tell me how to fix this problem?


How to write conditional equations within equation tags

I used following tags to create equations in my document. But when I tried to add conditional equation within this tag, it didn't work properly. Is there any way to add conditional statement within equation tags?    \begin{equation}     \begin{cases}          xxxxx, & \text{xxx}\\          xxxxx, & \text{xxx}      \end{cases}   \end{equation}


(1) For every $n\in \Bbb N$, there exist squarefree numbers $x$ and $y$ such that $x+y=n$, i.e., every natural number can be written as the sum of two squarefree numbers; (2) For every $n\in \Bbb N$, there exist squarefree numbers $k$ and $l$ such that $k-l=n$, i.e., every natural number can be written as the difference of two squarefree numbers.   For the squarefree numbers, I only know the definition of it, and I really did not quite understand how to prove these two from the definition.   Any help, please. Thanks in advance.


How to display loading image while actual image is downloading

Sometimes images take some time to render in the browser. I want to show a busy image while the actual image is downloading, and when the image is downloaded, the busy image is removed and the actual image should be shown. How can I do this with JQuery or any javascript?


Can i upgrade my mid 2012 macbook pro to use DDR4 ram ? Checking Apple > About this Mac > Memory i got the following  Your Mac contains 2 memory slots, each of which accepts a 1600 MHz DDR3 memory module.   Which seems to suggest not, but i wondered if DDR4 was even around at the time my mac was made, is Ram a backwards compatible upgrade like placing a Sata SSD in a 10 year old device ?


French work permit holder: visa required for a visit to the UK?

I have a quite specific issue here : I am living and working in London (I am French), and my friend would like to come for a few days. The thing is, my friend is Chinese, but is working in France for a few years, so she has French work permit, does she need to apply for a "Standard Visitor visa" anyway?  Precision: I know that Schengen and UK have different types of visa, but as she has a long-time permit in France, can she be considered differently than just a Chinese citizen?


Im trying to make a forest scene of a path and I want it to seem like the path is infinite or the path goes on for a very long time.  Im gonna also add trees to the side of the path and an HDRI for the sky.  I wanna know what I should set the camera settings and the plane size to so that the screen will be filled but appear to be infinite.  All help will be appreciated.  Thanks


propositional calculus problem, is this right proof?


How to obtain Rectangular Lines between nodes with tikz?

Sorry if duplicate (I'm sure duplicate) but I really can't find the way to do it in manual. I have created next block chain.     Here you can see curved line between last and third blocks. But I want something like this:  And the question: how can I сonnect them in this way? I'm sure that it is pretty simple. MWE:  \documentclass{article}  \usepackage{tikz} \usetikzlibrary{shapes,arrows,positioning,automata}  \begin{document} \begin{tikzpicture} \node[draw, thick, rectangle] (0) {Data arrival}; \node[draw, thick, rectangle, below of=0] (1) {Coks backoff procedure}; \node[draw, thick, rectangle, below of= 1] (2) {Get trigger-frame?}; \node[draw, thick, rectangle, below of= 2] (3) {Performs backoff procedure}; \node[draw, thick, shape aspect=2.7, diamond, below =0.5cm of 3] (4) {$b<0$?};   \path[>=latex, auto = right,every loop]  (0) edge[] node {} (1) (1) edge node {} (2) (2) edge node {} (3) (3) edge node {} (4) (4.east) edge[in=0, out=0, looseness=3] node[right] {N} (2.east) ;      \end{tikzpicture} \end{document}


How to manage users and groups using GUI?

Just switched from 10.04 to 11.10. I'm wondering about the limited options in the GUI for managing users and groups. Where is the old GUI to change groups, id's, etc. I know that I can do this from cli, that's no problem. But I want this comfortable GUI back.


A formula for the power sums: $1^n+2^n+\dotsc +k^n=\,$?

Is there explicit formula for the expression $1^n + 2^n + \dotsc + k^n\,$?  I know that for $n=1$ the explicit formula becomes $S=k(k+1)/2$ and for $n=3$ the formula becomes $S^2$. But what about general $n$?  I know there is a way using the Taylor expansion of $f(x)=1/(1-x)=1+x+x^2+\dotsc\;$, by differentiating it and then multiplying by $x$ and then differentiating again. Repeating this $n$ times, we get  $$\frac{d}{dx}(x\frac{d}{dx}(\dots x\frac{d}{dx}f(x))\dots )=1+2^nx^n+3^nx^n\dots.$$  Now do the same process but with the function $g(x)=x^{k+1}f(x)$. Then subtract them and we get $1+2^nx^n+\dots k^nx^n$. Because we have the explicit formulas $f(x)$ and $g(x)$ we can find the explicit formula by this process for arbitrary $n$. A big problem is that as $n$ grows, it is going take a lot of time finding the explicit formula. My question is therefore: are there other ways?


So this a fundamental assumption in mathematics. Can someone explain informally what it actually is please.  My guess is that its when we say in proofs that "Let $x \in X$". But I am not sure.


Adding curved features to map with ArcGIS API for JavaScript?

I've tried without much success to add a curved line feature to the ArcGIS JavaScript map.    I created a polygon with a curved edge in ArcMap:   However, when I load this same feature in the web API, it becomes segmented:   The problem started when I tried to create a curved feature from the JavaScript API itself, which only seems to allow full circle features (not circular arcs).  This makes me think that curves are still unsupported in the JavaScript API. Do you know any way around this? Do you have any other ideas on alternatives I can use to create and correctly view curved features?


I tried finding this on here, but couldn't so sorry if it's a duplicate.  Say I have 2 groups and a user: group1, group2, user1 with the following structure: group1 is a member of group 2, user1 is a member of group1  Now say I have the following files with relevant permissions  file1 root:group1 660 file2 root:group2 660   Now when I log into user1, I'm able to edit file1, but not edit file2. Short of adding user1 to group2, is there any way of doing this? or is there no way?  I'm using Ubuntu btw.


For any set $A$, prove that the cardinality of $A$ is no larger than the cardinality of $\mathcal{P}(A)$.  Please help! Thanks!


Deep Format of a Harddrive on a Linux System

I've got an original Asus Eee PC Netbook that I'd like to sell.  When I've sold old computers in the past, I've typically done a deep/secure/zeroing out style format.  How can I do this on a Linux Netbook?  I'm looking for   The command that will let me do this Advice on how I can do this on a device with (seemingly?) non-removable media   Thanks in advance!


Proving that a function is not holomorphic on the disk

Let $f \in C(\overline{D(0,1)})$ and $f(\frac{1}{n})=\frac{1}{n+1}$ for $n = 2,3 ...$ Show that $f \notin H(D(0,1))$ Attempted Solution: If I understand the problem correctly, I should show that $f$ is not differentiable on the unit disc centered at the origin. Hence, the limit: $$ \lim_{z\rightarrow 0} \frac{f(z) -f(0)}{z-0}         $$ does not exist. I'm guessing that I should approach $0$ through the sequence $\frac{1}{n}$ and that should somehow enable me to show that the limit does not exist. But, I don't quite understand how I should go about doing that. Can anyone give me some clues?


My phone won't give me Storage no matter what I do

So I try to download an app but a thing pops up saying I can't because I don't have enough storage on my phone so I go to my settings and I delete some apps and some pictures on my phone but it didn't do anything it still said I have 0 storage! So I get a flash drive and download all my photos on to it and then go back on my phone and delete them all ( well all most all of them I had 1300 photos  and I deleted like 700 photos)and I go back and there was no change my pictures was still using the same amount of storage and it still said I have 0 space left! It's making me mad! Please help! ( do I need a new phone??) Ps.i also deleted a bunch of old text messages and group chats but that didn't do anything either!


$P(X<Y)$ where X and Y are exponential with means $2$ and $1$

Given that $X$ and $Y$ are independent variables and that $X$ is exponential with a mean of $2$ and $Y$ is exponential with a mean of $1$. Find $P(X<Y)$?   From the information it can be concluded that $X \sim \operatorname{Exp}(\frac{1}{2})$ and $Y \sim \operatorname{Exp}(1)$  Hence, $f(x,y) = \frac{1}{2}e^{-\frac{1}{2}x} e^{-y} $  Therefore, $P(X<Y) = \int_{0}^{\infty} \int_{0}^{y} \frac{1}{2}e^{-\frac{1}{2}x} e^{-y} \,\,dx dy = \frac{1}{3}$   Is this the correct way to solve this problem?


Why sometimes the number of total-votes is different between various communities?

I think the algorithm of calculating the number of votes for each question/answer is different between different communities.  Here is one of my question on the StackExchange:    As you see, StackExchange shows the number of total_votes of that question is 6.  Here is the same question in the stackverflow:    And as you see, stackoverflow shows the number of total_votes of that question is 4. (even there isn't any downvote which makes a error-possibility in the calculation)  Well, why there is two different number as total-votes-number for on question when I open it on stachoverflow and stackexchange (list of questions) ?  I always taught all communities use of an identical algorithm for every task. But it seems wrong ...!


is it a safe code from mysql injections?some suggestions please

I am developing a system for a client. I need some suggestions for that. Is this a safe code to prevent sql injection?  $username=$_POST["username"]; $password=md5($_POST["password"]);  $num_rows=mysql_num_rows(mysql_query("select * from table where username='$username' AND password='$password'"));  if($num_rows>0) {     echo "Logged in"; } else  {     echo "Incorrect username or password"; }   Thanks in advance for your suggestions. Please elaborate your answer why the above code is unsafe.Thanks please dont negative vote the question if you dont have any answer.


My number of figure display in paragraph

I don't know which part of code make it happened  %%%%%%%%%%%%%%%%%%%%%%LIST OF FIGURES%%%%%%%%%%%%%%%%%%% \renewcommand\listoffigures{ \if@draftmode\else     \if@twocolumn     \@restonecoltrue\onecolumn     \else     \@restonecolfalse     \fi     \chapter*{\listfigurename}     \renewcommand{\@althead}{\hspace{0.3\textwidth}LIST OF FIGURES~(Cont.)\hfil}     \pagestyle{headings}     \thispagestyle{tocheadings}     \linespacing{1.3}     \addcontentsline{toc}{chapter}{\normalfont \MakeTextUppercase\listfigurename}     \@starttoc{lof} % must go after addcontentsline     \if@restonecol\twocolumn\fi \fi } %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   -  \newcommand{\figuretable}[3]{\begin{tabu}{|X|X|}     \hline     \multicolumn{2}{|c|}{#1}\\     \hline     \textbf{Project}: \@title \newline\newline \textbf{System}: {#2} \newline & \textbf{Major Advisor}:\newline \@majoradvisor \\     \hline     \multicolumn{2}{|p{\dimexpr \linewidth-2\tabcolsep}|}{\textbf{Description}: {#3} \newline} \\     \hline \end{tabu} }   -  %Figure 2.3: “Film” entity in wikidata \ref{fig:203}. \begin{figure}[htb] \centering \includegraphics[width=\linewidth]{figures/chap2/203.png} \caption{“Film” entity in wikidata} \label{fig:203} \end{figure}[![enter image description here][1]][1]


What are methods of Object Class in Python?

How to check methods defined in any class in Python.  I am now studying Pandas and I have checked pandas documentation and python github code too.   I want to know about: DatetimeIndexResampler class. size() and count() are two methods of this class. What are the other methods defined inside this class. I have checked github and it's documentation too.


Which of the above is correct?  I am in a dilemma which one is correct. I have an inkling that has is right.


How to force Wine into acting like 32-bit Windows on 64-bit Ubuntu?

When installing Wine on 64-bit Ubuntu 12.04, both 64-bit support and 32-bit support get installed. If I run wine foo.exe where foo.exe is a 64-bit-aware installer, it thinks it's on 64-bit Windows. This would be fine if this mode didn't fail, but in my case, it does (yet the Wine database suggests the app I'm trying to install should work, presumably as a 32-bit app).  How do I tell Wine (and Winetricks) to use Wine in 32-bit-only mode?


Is it possible to create a toggle button in C# WinForms? I know that you can use a CheckBox control and set it's Appearance property to "Button", but it doesn't look right. I want it to appear sunken, not flat, when pressed. Any thoughts?


Is Linear Discriminate Analysis (LDA) and Fisher Discriminant Analysis (FDA) same meaning? And also Fisher Criterion (FC)? Do these three terms interchangeably, having the same meaning?


How to remove the tab-like space after an empty line?

I want to write sth like:  aaaaaaaaaa  [empty line]  bbbbbbbbb  but instead I often get this:  aaaaaaaaaaaa  [empty line]  __bbbbbbbbbb  When I try skips inbetween, they do not start where they should, but rather in the middle of the text.


Reply for Look forward to seeing you tomorrow

I would like to reply to a statement Look forward to seeing you tomorrow.   Can I write I look forward too to see you tomorrow?   OR   I look forward to see you tomorrow too/as well?  I would appreciate if anyone could point out the mistake(s) in the above two responses. Also, if the two statements are not correct, what could be the alternative sentence?  Thank you for your help.


Good Evening people,  I recently started working in Java (from Python).The issue occurs when I'm trying to split a string and then test some of its elements.  I checked many other answers to similar questions but nothing solved my issue.  String str = "0 0 0 0 0"; String[] splitString = str.split("\\s");   The System.out.println(splitString[0] == "0"); always outputs false !  However System.out.println(splitString[0].contains("0")); evaluates to true.  I fear that I'm doing something really stupid but I'd like to know if someone could help me here :)  Cheers,  Alex


What's the difference between correlation and simple linear regression?

In particular, I am referring to the Pearson product-moment correlation coefficient.


Quick way to find the number of the group homomorphisms $\phi:{\bf Z}_3\to{\bf Z}_6$?

Consider the following multiple choice problem:  Let $H$ be the set of all group homomorphsims $\phi:{\bf Z}_3\to{\bf Z}_6$. How many functions does $H$ contain? A.1  B.2 C.3 D.4 E.6  Since $1$ generates ${\bf Z}_3$, one can analyze $\phi(1)$ case by case, which may be rather time consuming, for me, at least. Since this is a multiple choice problem, is there any quick way to solve it?


"In real life" vs "In a real life" vs "In the real life"

Should I use an article in such phrases, and if I should - which one? Examples:   In [?] real life you shouldn't do that. In [?] real life things aren't so simple. In [?] real life it's almost useless.


I guess the canonical proof to this problem is attained using the Euclidean Algorithm (I've seen some posts like this already). I came with this proof, based on gcd definition and some divisibility properties. I'd like to know if it seems correct to you.  Proof:  Let $d$ be a common divisor of both terms. Then $n! +1$ = $d$.$s$ and $(n+1)! +1 = d.t$, for $s, t$ in $\Bbb Z/{0}$. Therefore $(n +1)n! + 1 = n.n! + n! + 1 = n.n! + d.s = d.t$, and it follows that $d|n.n!$. Now, since $n=d(t-s)/n!$, $d|n$. Then $d$ must divide 1 ($n! + 1 = d.s$), and $|d|$ = 1. Being $d'$ another common divisor, it is clear that $d'$ must divide 1 also, and therefore it does divide $d$, so we have $d = gcd(n! + 1, (n+1)! +1) = 1$


About 8 Month ago, my postfix worked, now it does not work, does my log file look ok?  Aug 21 17:00:34 localhost postfix/master[9342]: daemon started -- version 2.7.0, configuration /etc/postfix Aug 21 17:01:11 localhost postfix/smtpd[9354]: connect from localhost.localdomain[127.0.0.1] Aug 21 17:01:11 localhost postfix/smtpd[9354]: C691694D4F: client=localhost.localdomain[127.0.0.1] Aug 21 17:01:11 localhost postfix/cleanup[9358]: C691694D4F: message-id=<52152a97a19ea_1f7542665f21564a@li534-212.mail> Aug 21 17:01:11 localhost postfix/qmgr[9345]: C691694D4F: from=<administrator@mcmdacm.com>, size=746, nrcpt=1 (queue active) Aug 21 17:01:11 localhost postfix/smtpd[9354]: disconnect from localhost.localdomain[127.0.0.1] Aug 21 17:01:12 localhost postfix/smtp[9359]: C691694D4F: to=<xxxxx.yyyyy@gmail.com>, relay=gmail-smtp-in.l.google.com[173.194.68.26]:25, delay=0.35, delays=0.05/0.01/0.12/0.16, dsn=2.0.0, status=sent (250 2.0.0 OK 1377118871 f10si5584777qai.16 - gsmtp) Aug 21 17:01:12 localhost postfix/qmgr[9345]: C691694D4F: removed   (Note:  I changed actual email to: xxxxx.yyyyy@gmail.com)  I did some tracing, results below  $ host -t A smtp.gmail.com smtp.gmail.com is an alias for gmail-smtp-msa.l.google.com. gmail-smtp-msa.l.google.com has address 173.194.68.108 gmail-smtp-msa.l.google.com has address 173.194.68.109  $ host -t MX gmail.com gmail.com mail is handled by 30 alt3.gmail-smtp-in.l.google.com. gmail.com mail is handled by 10 alt1.gmail-smtp-in.l.google.com. gmail.com mail is handled by 40 alt4.gmail-smtp-in.l.google.com. gmail.com mail is handled by 5 gmail-smtp-in.l.google.com. gmail.com mail is handled by 20 alt2.gmail-smtp-in.l.google.com. $    I am pretty new to email, so is it possible that I was black-listed somewhere by any chance?  Edit 8/22/13: OK, got the answer, email can be sent, but email servers will reject it unless criteria is filled, see the


Identical float values comparing as inequal

I was working on some 'determine the output' questions in C. I came across this question which looked simple on the face of it, but after running the code left me puzzled.   The output I expected was "True". However upon running, it was "False". And when I checked the value of f using printf(), it showed 0.1. Can someone please explain why f being assigned 0.1 doesn't return true for the IF statement?   There was no explanation for the answer from where I picked the question up, and I wasn't able to find an answer myself.   #include <stdio.h>  int main() {     float f = 0.1;     if (f == 0.1)         printf("True");     else         printf("False"); }


I'm having trouble figuring out how to evaluate:  $$\sum _{j = 1}^{n} j!j$$  I've tried plugging in numbers and looking for a pattern and I've also tried to find a general form like:  $$n=1:$$ $$ 1*1 = 1 = n^2$$ $$n =2:$$ $$ 1*1 + 1*2*2 = 5  = (n-1)^2 + (n-1)(n)^2$$  Could anyone point me in the right direction?


I've found a Bug with the new stack exchange bar

As you can see from the below image, the black top bar seems to stop when I scroll the page to the right.    Can this glitch be fixed?


What is the difference to declare a pointer before the malloc

I am learning about malloc function & I see this difference but I cannot understand it What is the difference between ptr = (*int) malloc(sizeof(int)*N)  and ptr = malloc(sizeof(int)*N)


I'm curious to know what the chown command does. In the manual page it says the chown command changes the file owner and group. I know the owner is the one that created the file(unless changed), but what are groups and when do we create a group?


I trying to do my second full project after finishing Chris  Plush's Pretzel.  So I am on to Blenderguru's anvil and have I stalled.  Cutting the circular slots with a cylinder into the anvil built from a plane has been terrible.  My problem is after I finish the the boolean modifier.  Because of the model design I need to go inside of the newly cut circular semi-circle and line up the new vertical edges with the preexisting horizontal edges.  Now I have my anvil with 2 semi-circular cuts in the base with all the geometry lined up and I go to apply the Subsurface and disaster.  The bottom layer of the geometry is gathering together in the middle of the center of the 2 semi-circles.  I have tried this with a miroir, using the loopcut to divide the mesh before the modifier and after the modifier.  I have done it without a mirror and just did 2 cuts and still the same problem.Does anybody have any suggestions on what might be happening to the bottom layer of geometry? Thanks Wayne


Hello I am a student and had the following problems in inequality: $-2\le 1 $ Squaring both sides the sign changes  $4\gt 1$ But for  $-1\lt 1$ Squaring the terms we get  $1\le 1$ I am stuck here please help me to understand this concept


System showing specified dll.application extension not found :    I tried installing Adobe Reader DC on my Windows 7 laptop and it couldn't load because the extension MSVCP120.dll was missing from my computer. I downloaded the extension and tried to register it, but the computer kept saying that the module msvcp120.dll failed to load and could not be found.  What should I do?


How does current flow in a short circuit?

In a short circuit, the potential difference across the terminals of a battery (consider a single cell with internal resistance)is 0 according to the equation  $$V=E-Ir,$$ where $r$ is internal resistance of the cell,$E$ is the emf of the cell and $V$ is a potential difference across the battery.   If the potential difference across any two points in a circuit is 0, the electric current $I$ doesn't flow right? Then how does current flow in a short circuit (assume 0 resistance for short-circuited wire)?


I'm trying to prevent sql injection in my code. so how can i rewrite this code using prepared statement.   This is my first code that work fine but open to sql injection  <?php     if(isset($_SESSION['em'])){      $eml = $_SESSION['em'];     $query = ("select id,fst,las,uid,pass,email,sts,ocp from Users where id !=0");     $res = mysqli_query($conn,$query);      if(mysqli_num_rows($res) > 0){        while($row = mysqli_fetch_assoc($res)){     $_SESSION['ids'] = $row['id'];     echo $row['fst'];     echo $row['ocp'];     echo $row['las'];       }     }     }      ?>   how can i use prepared statement for the same code please


I am curious as to whether set blacksmith plans sometimes drop only from certain sources. I am under the impression (right now) that all blacksmith plans drop unniversaly and random. Unlike the legendary crafting materials where you have to fight specific super-bosses.  Is this the case?  Can I get all pieces of the "Hallowed" set () Randomly throughout the rift, without having to farm a specific situation?


sudo apt-get update and adding a repository error

Whenever I sudo apt-get update I get an error. Here are the errors from the log:    Err:13 http://ppa.launchpad.net/ehoover/compholio/ubuntu eoan Release    404  Not Found [IP: 91.189.95.83 80]     Err:14   http://ppa.launchpad.net/gnome-terminator/ppa/ubuntu eoan Release        404  Not Found [IP: 91.189.95.83 80]    Err:15   http://ppa.launchpad.net/pipelight/stable/ubuntu eoan Release          404  Not Found [IP: 91.189.95.83 80]     E: The repository 'http://ppa.launchpad.net/ehoover/compholio/ubuntu    eoan Release' does not have a Release file.     N: Updating from such a repository can't be done securely, and is    therefore disabled by default.     N: See apt-secure(8) manpage for repository creation and user    configuration details.     E: The repository 'http://ppa.launchpad.net/gnome-terminator/ppa/ubuntu    eoan Release' does not have a Release file.     N: Updating from such a repository can't be done securely, and is    therefore disabled by default.     N: See apt-secure(8) manpage for repository creation and user   configuration details.      E: The repository   'http://ppa.launchpad.net/pipelight/stable/ubuntu eoan Release' does   not have a Release file.      N: Updating from such a repository can't be   done securely, and is therefore disabled by default.      N: See   apt-secure(8) manpage for repository creation and user configuration   details.   also when I try for example sudo add-apt-repository ppa:openrazer/daily or adding any other repository, I get a similar error  Can someone help me solve this? there are some answers over the internet, but I'm a beginner, so I can't understand how to fix my specific problem and not similar problems... thanks in advance!


What is the average time taken to populate tracking data in Marketing cloud and "Individual Email Results" in Sales Cloud

I am working on a API triggered journey with a single email send activity. Though the trigger successfully sent the email and also received the email.  I am unable to see the trackig data neighter in Marketing cloud "My Tracking". Nor in "Individual Email Results" in Sales Cloud


How to free up boot partition space more after removing old kernels?

I am upgrading from Ubuntu 14.04 to 16.04. When I tried to upgrade it threw errors about not enough memory space. After searching on the web I found out deleting old kernel helps. I deleted old kernel, and was successful in freeing up space. However, the upgrade still needs more space (more than 3 GB). How can more space be made available?. My partition is of 19GB


Chapter on the right side - How to turn it off?

As a documentclass I use book. Chapters always start on the right hand side.  How can I turn it off? I don't want to have empty pages. I don't care on which side starts  new chapter.


How do I copy a file in Python?  I couldn't find anything under .


The exact question is $ABC$ is a triangle. Find the locus of $P$ if $PA^2 + PB^2 = PC^2$. I have solved similar questions in Coordinate geometry where coordinates of the sides were given and I know the locus is a line, but I'm not able to conlude anything in the general case. I tried using, $PA^2 + PB^2 + PC^2=GA^2+GB^2+GC^2+3PG^2$ But couldn't proceed further, I also tried to draw medians to AG from P but arrived at the same equation.


I have a thread class:  private class Mythread extends Thread{        boolean mfinish = false;        private void finish(){            mfinish = true;            interrupt();        }        while(!mfinish){ do my work} }   and I use SparseArray<Mythread> mThreadArray to hold threads.  I registered a BroadcastReceiver in my service A:  private BroadcastReceiver myBroadcastReceiver = new BroadcastReceiver(){          public void onReceive(Context context, Intent intent) {           if(intent.getAction().euqals(STOP_THREAD)){                uid = bundle.getInt("uid");                pid = bundle.getInt("pid");                tid = bundle.getInt("tid");                if(mThreadArray.get(tid)==null){                     Mythread samplThread = new Mythread(pid, tid);                   mThreadArray.put(tid,sampleMainThread);                   sampleThread.start();               }           }           if(intent.getAction().equals(STOP_THREAD)){               uid = bundle.getInt("uid");                pid = bundle.getInt("pid");                tid = bundle.getInt("tid");                if(mThreadArray.get(tid)!=null){                     mThreadArray.get(tid).finish();                   mThreadArray.remove(tid);               }           }      }  }   In another application B, sentBroadcast() when there is a thread is created or ended. However, in my service A, I found the created threads can't be stopped when the "stop" intent comes.  Does any body know the reason?


Gear Theory -- Entanglement -- Spooky action at a distance explained?

Nothing can travel faster than the speed of light. Not even an electrical signal. Entanglement seems to violate this. But, does it?  Imagine 100 gears lined up in sequence all the way across a basketball court. As you turn the gear under one hoop, all 100 gears simultaneously spin.  Even the gear across the court would simultaneously spin.  Could you in theory connect gears a longer distance? Even Miles?   Imagine 100 basketballs in a straight line from one hoop to the other hoop with gears around the circumference parallel to the floor. You spin one ball, and they all spin.  Spinning the ball under one hoop, simultaneously spins the other ball.  Imagine, the in-between balls were not visible. Would this be a similar pattern to what we are seeing with entanglement?  Is it possible that it is not empty space between the two particles, yet some gear like matter that is connecting entangled particles?  Gear Theory --THE END--


Dual boot with Windows 8.1 and Ubuntu 13.10

I have a laptop that had Windows 7 previously installed but now has Windows 8.1. I want to dual boot with Ubuntu 13.10. But I was curious on how to do this properly and in the case that GRUB messes up my computer just delete it and restore it to the original Windows bootloader. Also DON'T recommend EasyBCD. I don't mind using GRUB but I want to be sure I can remove Ubuntu and GRUB.


Colloquially, people tend to speak in "shorter sentences" and leave out words like pronouns and verbs such as do, be and have, especially when it's clear who or what they're talking about. They might also omit whole phrases:     Do you want me to try getting the shelf off for you?    -------> Want me to try?   Another example:     Are you sure you've got time?    -------> Sure you got time?   Now, what are the shortened versions of the following sentences?     Would you like a drink?      Do you have any green tea?   Are they shortened in the same way as the examples below?     Do you want a drink?   -------> Want a drink?      Have you got any green tea?    -------> Got any green tea?


Mathematically what is the difference between pure separable state and entangled state ?  Can anyone explain with equations?


Can I interrupt the process of rendering and resume it later?

Let's say I have a huge project with a rendering time of 1000 hours or more. I don't want my PC to work non-stop for that long. I want to say something like, 'Please stop rendering now and continue where you have left off later when I tell you to.'


installing android sdk in android studio

For some reason I couldn't download Android Studio and Android Studio bundle. I download them both separate each other. In install section of Android Studio there is a part to specify Android SDK location. I locate the Android SDK folder and go on but this error message appears for no reason:


How do I pass an unknown value to a choice key in pgfkeys?

Why is the parameter value not being passed to my code for the unknown key value here?  \documentclass{article} \usepackage{pgfkeys}  \makeatletter \def\ae@size{2cm} \pgfkeys{/ae/example/.cd,   size/.is choice,   size/small/.code=\def\ae@size{I am small},   size/medium/.code=\def\ae@size{I am medium},   size/large/.code=\def\ae@size{I am large},   size/.unknown/.code={\typeout{UNKNOWN  ----> #1}\def\ae@size{I am customized to#1}}, } \newcommand\problem[1]{%%   \pgfkeys{/ae/example/.cd,#1}%%   \ae@size     \par } \makeatother \begin{document}  \problem{size=small} \problem{size=medium} \problem{size=large} \problem{size=a different size}  \end{document}


We are new to Linux. We have a small charter school customer that is struggling with a lab solution and Ubuntu seems to be a good choice with a server and thin clients. I bought a used server and 5 Dell thin clients to put up a lab and test. I also downloaded Ubuntu server. Just need to know if I'm headed in the right direction and if anyone has any tips or ideas. All the students need is internet access(Maybe Chrome) and basic office programs. The immediate need is to get 15 up and going but the long range plan is for about 90. Please help!!  Jay


What are the similarities/differences between the behaviors of Quantum particles and bouncing droplets?

Bouncing droplets on a fluid surface show many weird behaviors of the quantum world. Look at this for example:    They can show tunneling, double-slit interference patterns, and even particle-antiparticle creation (when two solitary waves meet, according to the aforementioned reference). Some people take this as an approval of the pilot-wave interpretation.  What is the reason for this similarity of behavior between bouncing droplets and quantum particles? Is there any difference, where this analogy no longer works and droplets CANNOT mimic quantum particles? And, is this a hint that quantum behaviors might have a classical underlying reason, similar to what happens to the droplets?


What should the character limit(s) for first/last name inputs be?

We want to create input fields for a user's first and last names. What should the minimum and maximum limits be, if any, and why?


How do I write a mathematical equation for ARIMA(1,0,0)(1,1,0)[12] and How to substitute values of coefficients in that formula. Please help

How do I write a mathematical equation for ARIMA(1,0,0)(1,1,0)[12] and How to substitute values of coefficients in that formula. My model is   ARIMA(1,0,0)(1,1,0)[12] ## ARIMA(1,0,0)(1,1,0)[12]  ##  ## Coefficients: ##          ar1     sar1 ##       0.6606  -0.5763 ## s.e.  0.1143   0.1295


I have an account named as Chankey (local user). I had to use some commands like viewing the shadow file etc. I tried it using sudo command     sudo vim /etc/shadow   It said:      Chankey is not in the sudoers file. This incident will be reported.   How can I add this user Chankey to the sudoers file?


Travelling from US to Sri Lanka, do I need transit visa for Canada?

Passport : Sri Lankan Holding a valid US Visa (F1). Spending only 3.15 hours at Toronto Airport. Flying in through United and leaving to my next layover (London) in Air Canada.


Some irreducible character separates elements in different conjugacy classes

Let $x$ and $y$ be elements that are not conjugate in $G$.  Then there is some irreducible character $\chi$ such that $\chi(x) \not = \chi(y)$.   Clearly the "irreducible" part isn't important, since any character can be written as the sum of irreducible characters, but I'm having trouble going beyond that.  I'd appreciate a good hint over a full answer, and I'd be most interested in a way to construct a group representation $\varphi:G \to GL(V)$ of $G$ such that the character of the representation takes different values on $x$ and $y$.


Are there any published guidelines on how to chop up monsters for use as alchemical components?

I have a character with the Guild Artisan background. His guild was an Alchemists' Guild so he is proficient with the alchemist's tool kit.  I mentioned to the DM that I could theoretically chop up monster corpses for use as alchemical raw materials and he said it was a good idea but provided no guidance.  Is there any published material that explains how to do this in 5th edition? Because the last time I saw guidelines, they were in the AD&D Dungeon Master's Guide.


Should we always cuddle a toddler when it cries?

Whenever our 3-month old baby cries, as soon as we cuddle her, she will stop crying.   My worry is:   She will develop a habit out of this and grow too dependent on us cuddling her.   Should we leave her crying for a while to stop her demand cuddling so much?


Blender VSE slow regarding PC Capabilities

I am quite a newbie at Blender (v2.79b) and I noticed something disturbing while generating videos. I have 8C/16T, all the raw materials are on SSD and I can only see 1 core working on my machine with a 10% load on my CPU. I can see in the Task Manager that Blender has 40 threads but it seems only one is really working. I make FullHD H264 lossless videos with Blender, compression is done with Handbrake in a second time. I followed mostly video tutorials made by Mickeycal on YT to make the effects (cuts, speed, cross....). I use Blender Render. Do you have clues to speed up Blender's performance ? KR, OLM


Prove by mathematical induction that $2n ≤ 2^n$, for all integer $n≥1$?

I need to prove  $2n \leq 2^n$, for all integer $n≥1$ by mathematical induction?  This is how I prove this:  Prove:$2n ≤ 2^n$, for all integer $n≥1$  Proof: $2+4+6+...+2n=2^n$  $i.)$ Let $P(n)=1         P(1): 2(1)=2^1\implies 2=2$.        Hence, $P(1)$ is true.  $ii.)$  Assume that $P(n)$ is true for $n=k$, i.e, $2+4+6+...+2k=2^k$, and prove that $P(n)$ is also true for $n=k+1$, i.e, $2+4+6...+2(k+1)=2^{(k+1)}$  from the assumption add $2(k+1)$ on both sides so we have   $2+4+6...2k+2(k+1)=2^k+2(k+1)$  I'm confused with $2^k+2(k+1)$, I don't know how to make $2^k$ be equivalent to $2^{k+1}$.  I feel i'm doing something wrong.   Any help would be appreciated!


Where in the (Stack Exchange) world can I initiate a programming-related discussion?

I fired up Stack Overflow just now and entered in the search "best jquery tooltip plugin", and was met with a fine collection of perfectly clickable candidates ... many of which have been closed as not constructive.  I've read the FAQ and I get it; it's not necessarily a factual programming question, and at some point they have to .  Alas, I'm spoiled, and at this point I've pretty much convinced myself that if a SO post fails to generate traction then my question is untenable.  Where in the Stack Exchange universe does a question like the one above make the most sense?  Is it just flat out unacceptable anywhere?  Is there a stackdiscussion.com?  Should I be asking this in meta.stackoverflow?  .  But this is a programming question.  Factual?  debatable.  But most certainly a programming question.


I am currently in need of using apt-get on a chroot directory. The setup is the following.  I have a chroot setup with schroot. This chroot environment needs to be stripped down as much as possible. Therefore I am planning to remove apt-get and commin from the chroot environment.  I know that Gentoo has the possibility to use portage on a different root directory. Is this possible to set a different root directory for apt.get to install software into my chroot directory?  Thanks in advance


A bit silly, but I can't type this character ಠ, on ubuntu.  Some page say it should be this way  Ctrl+Shift type u0CA0   But it doesnt do anything. Even I find a shortcut for sublime that I didn't know that exist before try this.


Oracle shared memory exception ORA-04031

I'm trying to establish an Oracle database connection. It throws the following exception:  ORA-04031: unable to allocate 4048 bytes of shared memory    ("shared pool","unknown object","sga heap(1,0)","kglsim heap")   I have tried connecting the database through JDBC as well as  SQL Developer, however it throws the exception in both case.  How can I fix this?


NullPointer exception being thrown using .equals on string in java?

I have a 2d array of "#" and "." I am Passing into a method, I am then trying to iterate through the array and find how many "#" are in it. I keep getting a NULLPOINTER exception when using .equals. the method should return the amount of "#" in the array. I tried iterating through the 2d Array and then converted the 2d into a single dimension array and still am getting the EXCEPTION Im not sure what I am doing wrong, any help would be greatly appreciated.  my code is:  public static int countSeats(String[][] aud){     int openSeats = 0;     String [] audit;    audit = new String[120];     int k = 0;    for(int i= 0; i < aud.length; i++)        for(int j = 0; j < aud[i].length; j++)            audit[k++] = aud[i][j];      for(int i= 0; i <= audit.length; i++){           openSeats = audit[i].equals("#")? +1:+0;     } return openSeats;


Why does the StackExchange Android app not go back to last page?

I use the StackExchange app on my Android device and whenever I choose to display questions by a tag then go on to view a specific question from that tag I find out that whenever I press the back button from the question which I'm on it takes me to the tags page and I think this should not be.  When I click back from the question I'm on it should take me back to the list of questions that I was shown when I choose a tag.  I should only get back to the "tag page" when I click back button from the results page(results of questions that are under the tag I chose at first).  I wanna know if this happens with just me or its a bug that needs to be fixed.


My project is to develop an installer which is an executable for Windows, Mac and Ubuntu. The executables on Windows, Mac and Ubuntu are .exe, .app and .deb respectively. So, I converted my .jar file to a .exe file on Windows using a software called launch4j. And on MAC I used a software called Jar-Bundler to convert my jar in to .app file. I want to know if there is any specific software on Ubuntu to convert my jar file in to a .deb file.


How far away is Cosmic Background Radiation?

I've been reading about Cosmic Background Radiation (CMBR) lately.  My understanding so far is that this is the "Noise"/"Flash" from the big bang.  Assuming that information is correct, how far away is it traveling in order to reach us?  The way it was described to me makes it sound as if it should be coming from the "end" of the universe.  Or is it omnipresent?


Fix the footer to bottom but not following the mouse to scroll

I make a footer positioned absolute to the bottom

Copy Right www.example.com

  footer, .footer {     position: absolute;     width: 100%;     height:20%;     color: rgba(255,255,255,0.75);     background-color: #24292e; }   The footer works properly if the content is long enough, else the content is short the footer will float far beyond the bottom line  I tried to set position: fixed in which situation the footer follows the mouse to scroll.  How could I fix the footer to bottom but not following the mouse.


how to install ubuntu 12.04 on a new laptop

I have a new laptop with no OS on it and I would like to install Ubuntu 12.04 on it. Can any one tell me or guide me how to install ubuntu 12.04.


Why $I=\left\{p(x)\in \mathbb{Z}\left[X\right]:2\mid p(0)\right\}$ is not a principal ideal?

I saw  but I still do not understand:     What is the difference between ideal and principal ideal?     At my homework I had to prove to things about $I=\left\{p(x)\in \mathbb{Z}\left[X\right]:2\mid p(0)\right\}$: 1. That $I$ is an ideal. I prove it... 2. That $I$ is not a principal ideal.    Now how can I prove 2.? Why $I$ isn't a principal ideal?   Thank you!


i am new to java and i am getting an error while compiling.the error is 'nullpointerexception'

my code was:  package javaapplication1;   import java.io.Console; public class JavaApplication1 {       public static void main(String[] args) {          Console console =System.console();         // TODO code application logic here         String ageInString ;         ageInString= console.readLine("how old are you?  ");         int age = Integer.parseInt(ageInString);         if(age<18)         {console.printf("not valid");         System.exit(0);         }      }  }   and the error is:  Exception in thread "main" java.lang.NullPointerException     at javaapplication1.JavaApplication1.main(JavaApplication1.java:20) Java Result: 1


I would like to hear some philosophical arguments which justify the use of logic.   Additionally, if a justification of logic takes the form of an inference, is it a problem if this inference itself makes use of logic.   Can we justify logic in a way that is not circular? Is a circular justification a bad thing?  Thanks.


Is there a cryptography algorithm that will remain safe if P=NP?

From what I heard, many encryption algorithms are based on the assumption that some problems are computationally hard, i.e, NP-complete. In the unlikely event that someone proves that P=NP, these codes will break.  Is there a practical encryption algorithm that will remain safe even if P=NP? I.e, an algorithm that depends on problems that are more difficult than just NP-complete?  My guess is that the answer is no: to be practical, a code must be verified in polynomial time, i.e, the problem must be in NP. Is this correct?


Is while (true) with break bad programming practice?

I often use this code pattern:  while(true) {      //do something      if(<some condition>) {         break;     }  }      Another programmer told me that this was bad practice and that I should replace it with the more standard:  while(!<some condition>) {      //do something  }      His reasoning was that you could "forget the break" too easily and have an endless loop. I told him that in the second example you could just as easily put in a condition which never returned true and so just as easily have an endless loop, so both are equally valid practices.  Further, I often prefer the former as it makes the code easier to read when you have multiple break points, i.e. multiple conditions which get out of the loop.  Can anyone enrichen this argument by adding evidence for one side or the other?


How to determine the method used to launch a batch file?

I’ve created a single batch file that runs various apps on different servers when it is launched (different apps are run based upon computer name, day of week, time of day, etc.).  It isn’t actually a batch file but a link to a batch file (CMD actually) stored in a central network location for admins only.  Q:  How can I determine the method used to launch a batch file?  In other words, I’ve placed a shortcut to the batch file in the STARTUP group (folder) on the servers (so that it is run automatically when logging in to the server).  Then the batch file can do its thing and check the computer name, date/time, etc. and go from there).  But I’d also like to be able to run the batch file manually (either by clicking on a shortcut, launching it from the command prompt, from another batch file, from a group policy, etc.).  I just can’t figure out how to determine the method for launch a batch file.  Thanks


Converting cluster of Points to Polygons using QGIS

I have an input point layer that is grouped into clusters, so I want to have each cluster of points converted into polygon. This question  (this question was removed) seems to come close to what I wanted by it hasn't been answered. So basically, I need an algorithm in QGIS that will convert each cluster of points (based on attribute field) as seen below into a polygons?  I have tried  plugin and it gave me wrong result seen below...  A copy of my data is found .


Terminal Logo gets misplaced after changing the theme

Recently I changed my Ubuntu 18.04 theme to MacOS theme. No sooner I installed the theme, I found the misplaced terminal icon in terminal window. I tried uninstalling and re-installing the terminal, wandered in terminal preferences, but came with no result.  I need to know how the misplaced terminal logo can be removed or placed rightly.  This is how it looks like:


I'm trying to recreate tetris using processing for a school project. But I keep getting nullPointerExceptions when trying to call the fill function  this is the class:  package nl.HAN.game.eindOpdracht;  import processing.core.PApplet;  public class Block {     private PApplet app;     private int xPos;     private int yPos;     private int width;     private int height;     private boolean exploded;      public Block(PApplet app, int xPos, int yPos) {         //standaard         this.app = app;         this.xPos = xPos;         this.yPos = yPos;          this.width = (app.width / 3) / 10;         this.height = app.height / 20;         this.exploded = false;     }      public boolean isExploded() {         return exploded;     }      public void explode(){         this.exploded = true;     }      public void drop(){         this.yPos++;     }      public void move(int direction){         if(direction == 0){             this.xPos++;         } else {             this.xPos--;         }     }      public void draw(){         if(!exploded){             app.fill(200, 100, 100);         }     } }   this is the main class:  public static void main(String[] args) {      PApplet app = new PApplet();      //app.print("test");      Block block = new Block(app, 1, 1);      //block.draw();     app.fill(255);      String[] processingArgs = {"nl.han.ica.oopd.waterworld.WaterWorld"};     Main mySketch = new Main();      //PApplet.runSketch(processingArgs, mySketch); }   and this is the error:  Exception in thread "main" java.lang.NullPointerException     at processing.core.PApplet.fill(PApplet.java:14739)     at nl.HAN.game.eindOpdracht.Main.main(Main.java:18)


I've recently started to learn some C# scripting in Unity. I've been able to make my PlayerCube move around using Vector3 Transform.translations, but I want my camera to follow my cube while moving around, and it's not working since Unity can't find PlayerCube. How do I make make it so it understands that there's a PlayerCube?   using UnityEngine; using System.Collections;  public class CameraScript : MonoBehaviour {     Player = GameObject.Find("PlayerCube");      // Use this for initialization     void Start ()      {     //  GameObject.Find(PlayerCube);     }      // Update is called once per frame     void Update ()      {         Transform.LookAt (PlayerCube);     } }


vfat partition cannot be mounted with x-gvfs-show option

Got a problem with my laptop manufacturer's partition. It's FAT32-formatted and fails under same curcumstances as for topic starter at . It seems like vfat got a problem working with x-gvfs-show parameter. Also, I seek for more "painless" solution then "format-and-refill", because this one is created by the manufacturer and (as far as I know) got specific structure adapted for BIOS.


Let $K_{1}, K_{2}\subset \mathbb{R}^{n}$ compact sets, such that $K_{1}\cap K_{2}=\emptyset$. Prove that, there are open sets $U_{1}, U_{2}\subset \mathbb{R}^{n}$ disjoint such that $K_{1}\subset U_{1}$ and $K_{2}\subset U_{2}$.   My ideia is: how $K_{1}$ and $K_{2}$ are disjoint sets, then $d(K_{1},K_{2})>0$ and $K_{1}\subset \cup_{i=1}^{m}A_{i}$, $K_{2}\subset\cup_{j=1}^{n}B_{j}$, where $A_{i}$, $B_{j}$ are open sets covering $K_{1}$ and $K_{2}$, respectively (Borel-Lebesgue Theorem). Now, i take $U_{1}=:\cup_{i=1}^{m}A_{i}$ and $U_{2}:=\cup_{j=1}^{n}B_{j}$, but how can i conclude that $U_{1}$ and $U_{2}$ are a disjoint sets?  Does anyone have any ideas?


There are 6 periods in each working day of a school. In how many ways can one organize 5 subjects such that each subject is allowed at least one period? Is the answer 1800 or 3600 ?  I have asked this question before () in this site itself to understand the right answer - 3600 or 1800? @Ross Millikan has given me a convincing answer and explained idea of overcounting and why 3600 is wrong. Posting it again here to assert the answer is 1800 and not 3600, mainly because almost all websites give 3600 as answer and only one website gives answer as 1800. Listing the websites for reference  (1) Ans is 3600 see() (2) Ans is 3600 see question 15 in () (3) Ans is 3600 - see 8th question in () (4) Ans is 3600 - see example 5 in () These sites as well as almost all reputed sites give the answer as 3600. But answer is 1800 according to   Sorry for asking the question again. Please tell me which is the right answer. 1800 or 3600. Since I am preparing for my exams, I don't want to be in the wrong path and hence clarifying.