I know two things:   $\sum_{n=1}^{\infty}\frac{1}{n^{s}}$ converges if and only if $Re s > 1$ analytic continuation is expanding the domain of entire function.   I would like to find analytic continuation of Riemann zeta function.  But there is a problem, as we approach $Re s=1$ from right side the value of series goes to infinity. Then how it is possible to find a smooth crossing to the $Re s \le 1$ part, so that we would have formula calculating zeta function for all complex numbers?(expect case when $s=1$)

I am told that when computing the zeroes one does not use the normal definition of the rieman zeta function but an altogether different one that obeys the same functional relation. What is this other function that they use explicitly given?  Also if I were to take one of these non trivial zeroes and plug it into the original definition would my answer tend towards zero as I evaluate the series?


I've done this before, expect to mutate a file in place, something like $ tr '\t' ',' <file.txt >file.txt and well, clearly the > redirection truncates the file before < can read it; How do I mutate a file inplace without truncating/deleting it?

The  doesn't give me much hope, but I'm hoping it's an undocumented (and/or GNU-specific) feature.


I have a method which gets a string of consecutive bytes and i need an array of bytes out of it:   void  GetByteArray(string paddedResistance) {    unsigned char cmd[4]={0x00,0x00,0x00,0x00};      list<string> resistanceBytesAsString;      for (int i = 0; i < paddedResistance.size(); i+=2)    {        resistanceBytesAsString.push_back(paddedResistance.substr(i, 2));     } }   This is the input value : "00000100"  and i will split it and add it to the list as four separate strings:  00 00 01 00  I need to convert each of them in order to be able to populate the cmd unsigned char array but i can't figure out how to do it.  In C# i would use   Convert.ToByte(myString, 16);   to populate a byte array.

I'm working in a C++ unmanaged project.  I need to know how can I take a string like this "some data to encrypt" and get a byte[] array which I'm gonna use as the source for Encrypt.  In C# I do    for (int i = 0; i < text.Length; i++)     buffer[i] = (byte)text[i];   What I need to know is how to do the same but using unmanaged C++.  Thanks!


I just tried to install Internet Explorer using .  It brought up a terms of service screen in the terminal, which I couldn't figure out how to accept, so I ended up closing the terminal.  I'm now getting this error:  E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?   Looking at this question, , I tried Faheem's answer, but got this error.  kill -9 3849 bash: kill: (3849) - Operation not permitted   What else can I do?  It looked like the other answers could really mess up the system, and as I am new to Linux, I don't want to risk anything to mess it up too badly.  I am using Ubuntu 16.04.  Thank you for your help.

I get this error when trying to use apt-get:  E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?     How can I fix this?


recently everywhere I go online I will find little snippets of text replaced with   "It's a Trap!"   It seemed to start with yahoo.com, but it has expanded to biblegateway, google, and much more! I don't know why its doing this, what type of virus remover to get, or what to do in general. Anyone else having this problem? Thanks!

What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.


There have been talks that md5(md5) is better than md5 alone, but some say it doesn't do anything, can someone help on how to make this more secured? I'm so confused with the mixed feedback.  $query="INSERT INTO `users` (`email`, `password`)     VALUES('".mysqli_real_escape_string($link, $_POST['email'])."',            '".md5(md5($_POST['email']).$_POST['password'])."'           )";

Is hashing a password twice before storage any more or less secure than just hashing it once?  What I'm talking about is doing this:  $hashed_password = hash(hash($plaintext_password));   instead of just this:  $hashed_password = hash($plaintext_password);   If it is less secure, can you provide a good explanation (or a link to one)?  Also, does the hash function used make a difference?  Does it make any difference if you mix md5 and sha1 (for example) instead of repeating the same hash function?  Note 1:  When I say "double hashing" I'm talking about hashing a password twice in an attempt to make it more obscured.  I'm not talking about the .  Note 2:  I know I need to add a random salt to really make it secure.  The question is whether hashing twice with the same algorithm helps or hurts the hash.


I have not asked that many questions, so I do not really know. Basically I just revamped one of my answers where I corrected the sheer ignorance in it and actually found the answer to the question (or at least I believe I got very close), but I do not know if the user who asked the question already sees an alert that I edited it or do I need to notify him with a comment?

Does the OP of a question get a message in the inbox when I update my answer?  Or do I have to make all the time a comment saying "@OP I updated my answer".  (Its a bit annoying when there are a lot of requests coming after the answer, and SO suggests to move the discussion automatically to chat)


Let $H\le G$ and suppose that $[G:H]$ is the least positive prime factor of $|G|$. How to show that $H\triangleleft G$? I am confused in how to establish relation between the number of cosets of $H$ and its normalization. What does the condition "least prime factor" restrict for? Where should I begin?

Generalizing the case $p=2$ we would like to know if the statement below is true.  Let $p$ the smallest prime dividing the order of $G$. If $H$ is a subgroup of $G$ with index $p$ then $H$ is normal.


I have the following code which does not compile cause of this error:     Error 5   Cannot modify the return value of 'System.Collections.Generic.List.this[int]' because it is not a variable   The code looks like this:  List<myStruct> myList = new List<myStruct> { new myStruct { a = 3 } }; myList[0].a = 5;  struct myStruct {     public double a; }   However when myStruct is a class this compiles. I assume it has something to do with struct being an immutable object whereas a class-instance is per se a "dynamic, mutable" object, maybe there are some better explenations for this.

I have a list of structs and I want to change one element. For example :  MyList.Add(new MyStruct("john"); MyList.Add(new MyStruct("peter");   Now I want to change one element:  MyList[1].Name = "bob"   However, whenever I try and do this I get the following error:     Cannot modify the return value of   System.Collections.Generic.List.this[int]‘ because it is not   a variable   If I use a list of classes, the problem doesn't occur.  I guess the answer has to do with structs being a value type.  So, if I have a list of structs should I treat them as read-only? If I need to change elements in a list then I should use classes and not structs?


Hey guys can you help me with this? The problem setting is that X and Y are independent random variables and Z = Y / X. I want to verify that: $\displaystyle f_ Z(z)\, = \int _0^\infty {{y}} f_ Y(y)f_ X(yz) \, dy$ In other words, is this true? I hope the problem is clear. Thank you in advance. PS I know the answer but I'm looking to understand.

Suppose $X$ and $Y$ are independent positive random variables with probability density functions $f_X$ and $f_Y$ respectively. Show that $Z=X/Y$ is absolutely continuous and find its probability density function.   $\textbf{My Thought:}$ In order to show that $Z$ is absolutely continuous, I need to show that it has a commulative distribution function. Then I can also differentiate the latter to obtain the probability density function of $Z$. I have the following calculation \begin{align*} P(X/Y\leq z)&=P(X\ge zY,Y<0)+P(X\le zY,Y>0)\\ &=\int_{-\infty}^{0}\left(\int_{yz}^{\infty}f_{X}(x)dx\right)f_{Y}(y)dy+\int_{0}^{\infty}\left(\int_{-\infty}^{yz}f_{X}(x)dx\right)f_{Y}(y)dy\\ &=\int_{0}^{\infty}\left(\int_{0}^{yz}f_{X}(x)dx\right)f_{Y}(y)dy. \end{align*} Also, if $z<0$, then we have that $F_Z(z)=0,$ since $X,Y$ are positive random variables. Therefore the random variable $Z$ is continuous, and we can differentiate it to obtain the probability distribution function of $Z$. We have that $f_Z(z)=0$ if $z\leq 0,$ and otherwise we have $$f_Z(z)=\int_{0}^{\infty}yf_{X}(yz)f_Y(y)dy.$$    Is my reasoning above correct?  Any feedback is much appreciated.  Thank you for your time.


If a moderator deletes your post, what does it imply (assuming that no reason was given for the deletion)? Are you "in trouble"? For instance, if it seems to have been deleted inappropriately, is it fine to undelete it? And more generally, is it possible to get notification when your post is deleted? [Background: , which was deleted and is now locked.]

What circumstances can cause a question or answer to be deleted, and what does that actually mean?    How can a post be deleted? When can't I delete my own post? Can I still see my post even after it's deleted? Can I see a list of my deleted posts? How can I undelete one of my posts? What does deletion mean for a post? How do votes to delete work? What are the criteria for deletion? What else should I know about deleted posts? If I flag my question with a request to delete it, what will happen?       For more information, see the articles about  and  in the .


Having $n, m \neq 0 $ and $m^2 = 6n^2 $  How do I prove that $ n,m \notin \Bbb Z$  using somewhat formal methods?

Here's my proof for the irrationality of $\sqrt{6}$: Proof: Let $\sqrt{6}$ be a rational number. Then $\frac{a}{b}$ = $\sqrt{6}$ , where $a$ and $b$ are coprime. Therefore,  $a^2 = 6 b^2$. Here $a^2$ is divisible by both $2$ and $3$. Which means, $a$ too is divisible by both $2$ and $3$ (fundamental theorem of arithmetic). Thus, $6b^2=(3\cdot2\cdot k)^2$ ; where $k$ is an integer. $6b^2=36k^2$ or $b^2=6k^2$. Here $b^2$ is divisible by both $2$ and $3$. Which means, $b$ too is divisible by both $2$ and $3$. Therefore, $a$ and $b$ have common factors, which is a contradiction. Therefore $\sqrt{6}$ is not rational.  Is the above proof correct? Is there an easier way to prove this?


I have a question that could be trivial:  Let $X$ be a Banach space, with a sequence $\{x_n\} \subset X$. If $\forall f \in X^*, f(x_n) \to 0$, is it true that $x_n \to 0$ in $X$?  My idea is to first prove that $x_n$ should be convergent, and then use contradiction to prove that $x_n \to 0$. But I don't know what should be the whole picture of the proof. Thanks in advance!

Let $\{f_n\}_{n \geq 1}$ be a sequence of functions in $L^2[0,1]$ converging to $f$ weakly. Does it imply  that $f_n \to f$ in $L^2$-norm?  This question appeared in an exam paper on functional analysis which I failed to solve properly. Any help in this regard will be warmly appreciated. Thanks for your time.


What can cause that i get IllegalMonitorStateException in this code  synchronized(syncCount){     syncCount--;     syncCount.notify(); }   I'm little confused, since, as far as I know running thread must have monitor on object who's notify is called. It looks to me that my code can not be wrong, but somehow it is.

Why does this test program result in a java.lang.IllegalMonitorStateException?  public class test {     static Integer foo = new Integer(1);     public static void main(String[] args) {         synchronized(foo) {             foo++;             foo.notifyAll();         }         System.err.println("Success");     } }   Result:  Exception in thread "main" java.lang.IllegalMonitorStateException         at java.lang.Object.notifyAll(Native Method)         at test.main(test.java:6)


Here is my HTML code.
Men's Shirt (on hanger)   -   +    2 Suits

 Total £22.00
   Order now    JQuery code.  $(document).ready(function() { $('.cart_minus').click(function () {             alert("hai"); }); });   When I put same code in console then alert is shown. How could I solve this.

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


As far as I understand, the mean decreased accuracy of a variable is calculated in each tree recording the out of bag error of the variable and subtracting the out of bag error for the same sample used to construct the three but with the values of the variable permuted, then the differences across all trees are averaged and divided between the its standard deviation.  Let's use as an example the iris data:  > iris.rf <- randomForest(Species ~ ., data=iris, importance=TRUE,proximity=TRUE) > importance(iris.rf)                 setosa versicolor virginica MeanDecreaseAccuracy MeanDecreaseGini Sepal.Length  6.116697  7.5435799  7.778538            10.613957         9.794883 Sepal.Width   4.164530  0.2126826  5.441507             4.765478         2.466190 Petal.Length 22.008324 34.2143904 28.077054            34.708242        43.264116 Petal.Width  22.593229 31.8538872 32.629733            33.842020        43.715771   So, what is the interpretation for the values of response variable? I guess that it's the same interpretation of mean decrease accuracy but just for the values of the response variable, in this case "setosa" , "versicolor" and virignica". I read the documentation of the randomForest package and didn't find any explanation about that point.

After running a Random Forest Classifier on the Iris data set, I get an output that looks like this:                setosa  versicolor virginica MeanDecreaseAccuracy MeanDecreaseGini SLength     1.277324  1.632586   1.758101   1.2233029           9.173648 SWidth      1.007943  0.252736   1.014141   0.6293145           2.472105 PLength     3.685513  4.434083   4.133621   2.5139980          41.284869 PWidth      3.896375  4.421567   4.385642   2.5371353          46.323415   While I understand the last 2 columns, I don't understand what the numbers in the first 3 columns (the classes) are.  Can someone help me understand what the number 1.277324 (SLength, setosa) means please?


It might be a C++ beginner mistake but I'm really confused now by getting this compiler Error:  error: no matching function for call to 'B::B(A (*)())' note: candidates are: B::B(A*)   I have written two class which look simplified like this:  //a very simple class A class A { public:     A()     {         //do some stuff in Constructor     } }  //another class, that stores a pointer to an object of A as a field class B { private:     A* _a;  public:     //simply initialize the field in Constructor     B(A* a) : _a(a) { }      void doMagic()     {         //do something with _a         _a->xyz();     } }   And what I am calling in my code is this:  A a(); B b(&a); //here the error appears   What I want is to create an object a and pass its pointer to object b. So that I have access to a in b's members.  It must be just something in the call of B b(&a); Perhaps you can find out what my Problem is very easily.

Is there any good reason that an empty set of round brackets (parentheses) isn't valid for calling the default constructor in C++?  MyObject  object;  // ok - default ctor MyObject  object(blah); // ok  MyObject  object();  // error   I seem to type "()" automatically everytime. Is there a good reason this isn't allowed?


I am transiting through the UK on my trip from the US to Italy. I am arriving at Heathrow and will be going through immigration to get to Stansted, where I'm catching my flight to Italy. I am a Vietnamese citizen but hold a US visa and last entered the US on such a visa in June. Although my citizenship may require me to apply for a transit visa, I'm wondering if I could do without by meeting the transit without visa concession:    You might be eligible for ‘transit without visa’ if:   you arrive and depart by air have a confirmed onward flight that leaves on the day you arrive or before - midnight on the day after you arrive have the right documents for your destination (eg a visa for that country) you’re travelling from (or on part of a reasonable journey from) Australia, Canada, New Zealand or the USA and it’s less than 6 months since you last entered that country with a valid entry visa.   Also worth noting: I am doing a short study course in England this fall for my study abroad program, and I have acquired the appropriate visa for that. Unfortunately the valid date on this visa is the start date of my course, which is after when I wish to transit through the UK to do my Europe trip. I figure re-applying for a visa or applying for a transit visa would be a fuss and am hoping to be able to qualify for the concession. I would appreciate any thoughts and advice.

Is there a website or some other way to find out if I need a transit visa for a short stop in the UK on my way somewhere else? Ideally this should give me the answer for all nationalities, and take into account any other visas I may have.


I understand how unbelievably lucky the discoverers were to catch the wave produced billions of years ago by an event that happens so rarely one hour into a test run of their equipment. But one thing is still not clear to me – how did they know what exactly caused the spike? Was that merely a conclusion that this must have been two black holes colliding or there was any additional astronomical observation done that spotted the collision?  EDIT:   is similar, and one of the answers mentions that LIGO observation can not be interpreted as evidence of WHAT the actual event was, but it also never directly tells me if any proven-to-work ways of observation parallely detected the black hole merger.  Because if only LIGO was involved in detection, than how do we know WHEN and WHERE the merger happen? As far as I understand, LIGO technology does not communicate any space-time coordinates of the event. Or am I wrong?   and other articles insist that event took place 1.3 billion years ago.

Recent reports claim that the gravitational waves detected by LIGO match up with the signal expected from two black holes merging as predicted by general relativity.  Additionally, the masses of both black holes were estimated. Questions:  How certain are we that the detected of gravitational waves are necessarily from two black holes merging?  Since supermassive black holes are typically at the center of a host galaxy, what happened to the galaxies that contained the two merging black holes?  For example, did their host galaxies merge?    Edit After reading the answers, I understand that the signals detected by LIGO are proof of the validity of gravitational wave generational artifacts as predicted by general relativity.  When additionally gravitational waves, caused by the merger of the supermassive black holes (those which ARE indeed located in the centers of the merging galaxies) will be detected, since mergers of galaxies could be observed by the methods independent of gravitational waves such as registering the fact of the quasar appearance (). Additional questions:  Could someone offer me the historical ASTRONOMY precedent when the second degree of inference (from the mathematical model, being associated with the theory of Physics) was accepted as the discovery of the astronomical object?  Could someone give a reference to trustable scientific publication, with the subject of study being discussion of requirements satisfying claim of astronomical discovery of an astronomical object?  Have independent scientific sources (outside of members of the LIGO team) analyzed methodology and results of the LIGO signal detection, and published their conclusions with regards of what was actually discovered?


Short story about a guy thinking of leaving his spouse by substituting a lifelike android of self to cover in his absence. But when he finally decides he shouldn't follow through, he lays back down bed with his wife and when he rests his head on her chest he realizes from the sound that she has already done the switch herself, and she is off somewhere cheating on him and has left an android for him to snuggle with.  This would be an older story, I think I first read it in about 1974 or so. Most likely it was a mainstream well known sci-fi author if I was reading it in high school. The reason I am looking is I would love to find the haunting audio version of the story as read by Burgess Meredith.

I read a short story about four years ago and can't remember the title or author. The only thing I know is that it is relatively old -- like Huxley or Asimov era. Can anyone help me?   The basic synopsis is this: a man clones himself and has his clone do the parts of his life that he doesn't enjoy. He deceives his wife about this; she doesn't know he has a clone. Whenever the man and the clone are both home, the clone is locked in the "toolbox" in the basement. The clone starts to treat the man's wife better than he had previously. His wife starts to fall in love the clone, and the man decides he needs to get rid of the clone. When he tries to do so, the clone overpowers the man and locks him in the toolbox in the basement!  I'm hoping to share this story with my English class this school year. Any help is appreciated!


I just discovered a significant updated solution for the following topic:    I feel so compelled to share it, but this would be my first post.    How can I go about commenting to the topic or starting my own topic.  The issue has been alternate row coloring in a tablix.  An exhausted topic, but I had the issue of alternate row shading where the row group was sorted Z-A.  Using the Code.AlternateColor from the comments, I was able to achieve alternate row coloring on a sorted table and since I spent a lot of time trying to find the solution and realizing so many others have the same issue, I want to share.  Let me know the best way to share my solution (without a question really).

Questions can be protected (i.e. marked "highly active").   What does it mean for a question to be protected? Why are some questions protected? Who can protect and unprotect questions? Who can answer a protected question? How are protected questions displayed? When should I protect or unprotect a question? When does the Community user protect a question?


I have a windows 10 professional 64 bit OS on a PC I've recently built. I want to install Ubuntu along side it so I can boot into Windows for games, Ubuntu for everything else. I have a 1 TB M2 SSD that Windows is installed on that I want to split between the two OS's. When I try and install Ubuntu - I don't get an option to install along side windows and the partition screen confuses me. Can you help?

I'd like to see the full How-To on how to use manual partitioning during Ubuntu installation. The existing guides (at least those I found here) cover only automatic part and leave untouched the manual part (or extremely short and contain no pictures).  I'd like to cover such situations:     If your disk contains other systems:


I know how to prove "Infinite Sets Contain Countably Infinite Subsets". But I found that I have to use some kind of AC (at least DC or ACω). I read that in analysis the statement that can be proved by using AC can also be proved without using AC. Is there a way to prove this statement without using AC?  P.S.: Sorry, I didn't pose my complete logic so the "Dedekind" is a mis-input. "Infinite Set" here I mean is the opposite of "Finite Set", so please don't assume the infinite set is defined as Dedekind infinite. My complete logic is to use this fact as the lemma to prove that Dedekind infinite is equivalent to infinite. I appreciate for the nice answer given below, but that's not what I need. Description is edited already.

Set A is Dedekind infinite, i.e. there is a bijective function from A onto some proper subset B of A.  Please prove that A has a countably infinite proper subset.


I have the following XML file to read with Python:  <?xml version="1.0" encoding="UTF-8" standalone="true"?> <!DOCTYPE boost_serialization> <boost_serialization version="9" signature="serialization::archive">     <obj>          <count>2</count>          <item_version>0</item_version>         <item>3.1400001</item>         <item>7.3600001</item>      </obj>    </boost_serialization>   The python script I use to read this XML file is as follows:  from xml.dom import minidom xmldoc = minidom.parse('items.xml') itemlist = xmldoc.getElementsByTagName('item') print(len(itemlist)) print(itemlist[0].attributes['ATTRIBUTE_NAME'].value)    The problem with the script is ATTRIBUTE_NAME does not exist. If I print it with print itemlist[0].attributes.keys(), it is empty. So in this case how I can obtain the item values 3.1400001 and 7.3600001 ?

I am creating a GUI frontend for the Eve Online API in Python.  I have successfully pulled the XML data from their server.  I am trying to grab the value from a node called "name":  from xml.dom.minidom import parse dom = parse("C:\\eve.xml") name = dom.getElementsByTagName('name') print name   This seems to find the node, but the output is below:  [<DOM Element: name at 0x11e6d28>]   How could I get it to print the value of the node?


After installing some apps I am getting this error while trying to upgrade :    package is in a very bad inconsistent state; you should reinstall it before attempting configuration   its happening for sudo apt-get autoremove too. I tried solutions given in .  Please Help me.  NOTE: This error is occurring  after installing GIMP, WINE , Playonlinux , and reinstalling of Mozilla (I did all these continuously one after the other so I don't know specifically.)

I can't update my system because it freezes while installing a third-party update (zramswap-enabler)! Sometimes I get the following message in Update manager:  Could not initialize the package information An unresolvable problem occurred while initializing the package information. Please report this bug against the 'update-manager' package and include the following error message: E:The package zramswap-enabler needs to be reinstalled, but I can't find an archive for it.  I tried to remove the zramswap-enabler, but it's impossible because I get the following message: dpkg: error processing zramswap-enabler (--remove):  Package is in a very bad inconsistent state - you should  reinstall it before attempting a removal. Errors were encountered while processing:  zramswap-enabler E: Sub-process /usr/bin/dpkg returned an error code (1)  Actually I would really reinstall that package, but it is unable to do it! If I remove this third-party PPA then the system is warning me about a very very serious problem. So why can I not install/reinstall/remove/update this package and why freezes the updater if I try to update?


What this the best way to accomplish the following? using tabular ?  i dont want to use \hfill and pushing them to the end of the line.  • list-item           i want this • longggg-item        and this to be aligned • another-item        at the same level auto   in a more general way  • some text                  i want this                  same here • another text               and this to be at the        same here • not the same length        same level after let say     seconde level here

Current code is:  \begin{enumerate}[label=LEVEL \arabic{*},leftmargin=*]     \item Description of Level 1 \quad L1 \\ \emph{more text}     \item Description of Level 2 \quad L2 \\ \emph{more text}  \end{enumerate}   but the \quad does not align L1 and L2 uniformly vertically. I want to replace \quad with a tab but the tabbing environment does not allow mixing with an enumerate!


I bought a Dell Inspiron 5423 ultrabook with a 32GB SSD drive and a 500GB HDD. I tried to install Ubuntu with a live CD, but there is no drive shown on which to install Ubuntu. In my boot options I changed the boot option from UEFI to Legacy. I also changed the SATA option to ATA, but it's still not working.

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


I'd like to block access to websites on my Pixel 3 android device. The parental settings leave much to be desired and apps like BlockSite don't work across all browsers. (In this case - it doesn't work in firefox)   Here's what I tried so far   adb pull /system/etc/hosts ~/Documents/android/hosts   I edited the hosts file and got it ready to be transferred back.  adb push ~/Documents/android/hosts /system/hosts   This gave me error message: adb: error: failed to copy '/Users/[username]/Documents/android/hosts' to '/system/hosts': remote couldn't create file: Read-only file system  Per this  and this , I tried a few other options.  I tried to use these commands   adb root adb disable-verity adb reboot adb root adb remount   This gave me error message: adbd cannot run as root in production builds and when I tried adb disable-verity it said: verity cannot be disabled/enabled - USER build.  I tried to use this command  adp remount   This gave me error: Not running as root. Try "adb root" first.  I downloaded an emulator and tried this command on my device  mount -o rw,remount /system mount -o ro,remount /system   Similarly, this was unsuccessful

I'm using LineageOS 14.1 and don't want nor need to root it. How can I remount /system rw and edit /system/etc/hosts?  All answers in "" expect a rooted phone.


I cannot get to kibana through web UI. I'm set the necessary ports in firewall-cmd, I've configured kibana.yml and elasticsearch.yml. I'm not seeing any relevant errors, or at least don't know if they are if they are there. It just shows 'Site cannot be reached' for the appropriate port. Later on I would like to have put kibana on a subdomain kibana.domain.com, but I would first like to confirm that it's working without a subdomain. I can confirm that my domain and nginx are working Current versions: OS - Centos 8 Elasticsearch - 7.10.2 Kibana - I have no clue how to get the version through terminal (there aren't version conflicts to my knowledge so it shouldn't matter. It's 7.x) There is only one instance of kibana running on 5601 from what I can see. netstat -tulpn | grep LISTEN tcp        0      0 127.0.0.1:5601          0.0.0.0:*               LISTEN      290961/node tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      1/systemd tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      290425/nginx: maste tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      4738/sshd tcp        0      0 0.0.0.0:443             0.0.0.0:*               LISTEN      290425/nginx: maste tcp6       0      0 :::111                  :::*                    LISTEN      1/systemd tcp6       0      0 :::80                   :::*                    LISTEN      290425/nginx: maste tcp6       0      0 127.0.0.1:9200          :::*                    LISTEN      287716/java tcp6       0      0 127.0.0.1:9300          :::*                    LISTEN      287716/java tcp6       0      0 :::22                   :::*                    LISTEN      4738/sshd tcp6       0      0 :::443                  :::*                    LISTEN      290425/nginx: maste  kibana.yml server.port: 5601 server.host: "127.0.0.1" elasticsearch.hosts: ["http://127.0.0.1:9200"]  elasticsearch.yml cluster.name: portfolio_es_cluster node.name: portfolio_es_node path.data: /var/lib/elasticsearch path.logs: /var/log/elasticsearch network.host: 127.0.0.1 http.port: 9200  Curl for kibana locally works curl -XGET http://localhost:5601/status -I HTTP/1.1 200 OK content-security-policy: script-src 'unsafe-eval' 'self'; worker-src blob: 'self'; style-src 'unsafe-inline' 'self' kbn-name: mykibananame kbn-license-sig: d9d95bb2e2230b29804216ff76 content-type: text/html; charset=utf-8 cache-control: private, no-cache, no-store, must-revalidate content-length: 121035 vary: accept-encoding accept-ranges: bytes Date: Mon, 18 Jan 2021 06:53:36 GMT Connection: keep-alive  firewall-cmd --list-all public (active)   target: default   icmp-block-inversion: no   interfaces: eth0 eth1   sources:   services: cockpit dhcpv6-client http https ssh   ports: 5601/tcp 9200/tcp   protocols:   masquerade: no   forward-ports:   source-ports:   icmp-blocks:   rich rules:

I have just set up a wi-fi network at home. I have all my files on my desktop computer (192.168.1.56) and want to access localhost over there from another computer (192.168.1.2).  On my desktop I can access localhost through the normal . Apache is running on port 80 as usual.  Exactly what do I have to do to achieve this? There is documentation on the net but they either don't work or are too fragment and confusing to understand.  I think I have to make changes to my apache's httpd.conf file and the hosts file. Any ideas as to what changes to make?


On a mac high sierra 10.13.3 I have 256 open files. I want to raise it and I open a terminal and enter   sudo launchctl limit maxfiles 1000000 1000000   This doesnt change anything when I enter  ulimit -a    I still get 256  But it does change something, because when I enter    sudo launchctl limit maxfiles 1000 1000   the system just stops working until a restart.   What is the right way to Increase number of open files in mac high sierra  Following command changes the open files just for the specific terminal session   ulimit -n 4096

Before Mavericks, I could use /etc/launchd.conf file to change maximum system resource consumption, for example:  limit maxfiles 16384 unlimited limit maxproc 16384 unlimited   It no longer works in Mavericks.  What is the correct way to do it in the recent version of OS X?


I have asked the same question , but thought that is was a good idea to post it here also.  I am learning schemes theory at school and I have for now only lectures notes that I am taking during the course. The professor is quite often using following expressions, without having defined them : if $S$ is a scheme and if $f : X \rightarrow Y$ is a morphism of $S$-schemes he often says that some property P of $f$ is   (1) local on $X$  (2) local on $Y$  (3) local on $X$ and $Y$  (4) local on $X, Y$ and $S$  and I have several question on this, and related to this.  I went to the library to look at all Grothendieck's EGA's and found the same frequent use of the expression la question est locale sur in the same four cases - at least, maybe there are other than these four ? But I found in them no definition of the meaning of la question est locale sur, which means the question is local on in english.  I guess that (1) means that $f$ has the property P if and only if for every open cover $(U_i)_{i\in I}$ of $X$, all restrictions $f_{|U_i} : U_i \rightarrow Y$ have the property P, and that (2) means that $f$ has the property P if and only if for every open cover $(V_i)_{i\in I}$ of $Y$, all corestrictions $f^{-1} (V_i) \rightarrow V_i$ have the property P. For (3) obviously it is equivalent to check (1) and (2), but I cannot state a more synthetic formulation.  Does (3) means that $f$ has property P if and only if for every open cover $(U_i)_{i\in I}$ of $X$ and for every open cover $(V_j)_{j\in J}$ of $Y$ all morphisms $U_i \cap f^{-1} (V_j) \rightarrow V_j$ have the property P ? For (4) it is sufficient to define what means P is local on S. Does this means that $f$ has the property P if and only if for every open cover $(W_i)_{i\in I}$ of $S$, every morphism $p^{-1}(W_i) \cap f^{-1}(q^{-1} (W_i)) \rightarrow q^{-1} (W_i)$ has the property P ? Or is there something more clever than this. Combining this with (3) is equivalent to (4), but here again, is there a more synthetic formulation for this ?  In (1), (2), (3), (4) I used "local morphisms" (restrictions in (1), corestrictions in (2) etc). Is it possible to express these morphisms thanks to fiber products, and if so, how ?  In (1), (2), (3), (4) I used the word every cover but sometimes in the course it suffice to have the fact for only one cover to have it for all. How does this work ? (I call Q this question.)  Sometimes its not only open covers that are used, but open affine covers. For $i\in\{1,2,3,4\}$, is (i) equivalent to the assertion (i) with "open" replaced by "open affine", or even by "affine" ?  Is answering to question Q easier with "open" replaced by "open affine", or only "affine" ? Of this note, what does the following sentence mean : the property P of the morphism of $A$-algebras $\varphi : B' \rightarrow B$ is local on $\textrm{Spec}(A)$ (resp. on $\textrm{Spec}(B')$, resp. on $\textrm{Spec}(B)$, resp. on "combinations of the previous") ?   I have a last question : all the previous questions are local for the topology of the schemes involved, which is a topology in the "classic" sense. Is all of this translatable to Grothendieck topologies ? If so, how ? And then, intuitively, in the case of the Zariski site, is the same ?  I know that this was a lot of question, but all are intimately related to this "local on" stuff, so I preferred to ask all of them in one shot.


For this particular review:   The question got fifteen close votes over the course of an hour.  Seems like that's a lot.  This could indicate a bug.

I was in the Low Quality Review queue, and the following review confused me:    It's showing eight "Close votes", which should be more than enough to close a question.  I checked the question's , and it wasn't somehow closed, then re-opened in the middle of the review.  So I then checked on each of the users, and noticed that the majority of them are under 3000 reputation, meaning they can only "Recommend Close".    However, all reviews are simply showing as "Close", which is extremely confusing.  Is this a bug, or possibly an undocumented change related to ?    Another recent example:


At the beginning of Order of the Phoenix, when nobody believes Harry that Voldemort had returned, why didn't he just show everyone what happened via a pensieve. Surely there is no way to dispute the hard evidence in Harrys memories of his encounter with Voldemort at the end of Goblet of Fire

In Goblet of Fire, after the last task why didn't they simply use the pensieve to restore Harry's memory instead of making him relive the events?  Wouldn't this provide valuable evidence to make everyone believe Voldemort is back? It would be easier to make a ‘fellowship' if everyone was aware of what was coming which was clearly what Dumbledore wanted.  So why didn't he use the Pensieve?


I am a little bit confused after I found out that "e.g." is followed by a comma in American English. My confusion stems from the correct placement of this abbreviation. Consider the following sentence:     Usually, these entities are both represented in the source language,   e.g., as modules or top-level declarations, and easy to distinguish   from each other by the user and the compiler, e.g., as separate   files or directories.   When reading this sentence, I stumble upon the commas after the "e.g."s. I could understand it if the sentence was:     Usually, these entities are both represented in the source language,   as, e.g., modules or top-level declarations, and easy to distinguish   from each other by the user and the compiler, as, e.g., separate   files or directories.   The second version reads somewhat slower, there is more emphasis on the ".e.g." as I would like and the meaning of the second "as" might be confused to relate to the "compiler".   Is the first form correct? If so, I wonder what purpose the commas serve? Is the second version different in meaning from the first, or am I reading it wrong?

It seems that "e.g." is always followed by a comma but "i.e." is not. Why is that?


had 4.9 questions per day during it's BETA period and was declined the opportunity to turn into a full StackExchange site, but the  had only 3.4 questions per day and was approved.  All of the other metrics for both seem to have came up as Excellent.  Why was the role playing site approved, but the Startup site declined?

I really enjoyed that site. I've only posted on it once, but I enjoyed seeing other people's posts and appreciated reading about entrepreneurial dilemmas.


What I (think I) understand: When light is refracted in a medium (say glass), the light interacts with the electrons in the medium and the electrons create new waves.  Summing the waves with the original wave gives a group velocity slower than c because of phase lags.   What I'm confused about: How is light interacting with these electrons? It's not being absorbed.  it is described as being "virtually absorbed". I understand that  you can view a photon as taking every possible path and sum them, but they're if they don't have the energy to excite an electron, then why would summing a bunch of paths where it can't excite an electron result in "virtual absorption"? What does "virtually absorbed" mean?  describes it: "In an indirect way they're able to make the electrons wiggle."  What is this "indirect way"? Also is dispersion a continuous or discrete phenomenon and why?

I am currently reading about the interactions between light and matter, but I keep coming across conflicting explanations.  My initial understanding (using classical electrodynamics) was that light (EM) waves do not actually travel through glass. Instead, they are absorbed by the atoms and/or electrons within the glass, which then emit new EM waves. The new EM waves emitted by the energised particles make up the forward-radiation, which is the light observed from the opposite side of the glass. So it appears as if light is travelling through the glass, but it's actually being absorbed and then re-emitted with (mostly) the same properties.  The article  by Chad Orzel, based on a related SE question, confirms the above:      To understand the propagation of a wave through a medium, you can   think of each component of the medium– atoms, in the case of a glass   block– as being set into motion by the incoming wave, and then acting   as a point source of its own waves.   But an answer to a different but related question,  conflicts with the above:     the electrons in glass are tightly bound to atoms so they are not free   to move like the electrons in a metal and therefore they do not absorb   the photons.   I know the above is referring to the quantum electrodynamics understanding, but I think it still conflicts as it claims that EM waves are not absorbed by the electrons in glass because they are too tightly bound to their atoms.  Also, the  provides a small explanation of the mechanics behind refraction within glass, which kind of conflicts with both of the above:     In the case of dielectrics such as glass, the electric field of the   light acts on the electrons in the material, and the moving electrons   generate fields and become new radiators. The refracted light in the   glass is the combination of the forward radiation of the electrons and   the incident light. The reflected light is the combination of the   backward radiation of all of the electrons.   From my understanding, the above claims that some of the light is absorbed and re-emitted by the electrons (which conflicts with the linked answer), and that the rest of the incident light travels through the glass (makes up the rest of the refracted light) (which I think conflicts with the linked article, claiming the light is absorbed (although the article doesn't technically state whether all of the light is absorbed and re-emitted, so maybe that's where I'm going wrong(?))  I'm sure this is my misunderstanding, so I would be very grateful if you could clear it up for me:  When a light wave is incident on a sheet of glass, do the particles that make up the glass absorb the waves and re-emit them in the forward direction? Or do the light waves manage to travel through the glass, without being absorbed and then exit the glass?


I saw the following problem on Facebook (figure not drawn to scale):                                                              $\triangle ABC$ is an isosceles triangle with $AB\equiv BC$, $AC\equiv BD$, and $\angle B=20^\circ$. Find $\angle CAD$.   What I did was let $BC\equiv x$ and divide the triangle in two by bisecting $\angle B$. This yielded two right triangles with base $x\cos80^\circ$. Therefore, the base of $\triangle ABC$ has length $2x\cos80^\circ$.  Clearly, $DC=x-2x\cos80^\circ$, and $\angle C=80^\circ$.  Now, to find $AD\equiv y$, I used the law of cosines:  $$ y=\sqrt{(2x\cos80^\circ)^2+(x-2x\cos80^\circ)^2-2(2x\cos80^\circ)(x-2x\cos80^\circ)\cos80^\circ}. $$  Finally, to find $\angle CAD\equiv\theta$, I used the law of sines:  $$\begin{align} \frac{\sin80^\circ}{y}&=\frac{\sin\theta}{x-2x\cos80^\circ}\\ \Longrightarrow\theta&=70^\circ. \end{align}$$  Is my result correct? Is there an easier way to solve this problem?

$\triangle ABC$ is an isosceles triangle such that $AB=AC$ and $\angle  BAC$=$20^\circ$. And a point D is on $\overline{AC}$ so that AD=BC, , How to find $\angle{DBC}$?    I could not get how to use the condition $AD=BC$ , How do I use the condition to find $\angle{DBC}$?  EDIT 1: With MvG's observation, we can prove the following fact.     If we set on a point $O$ in $\triangle{ABC}$ such that $\triangle{OBC}$ is a regular triangle, then $O$ is the circumcenter of $\triangle{BCD}$.   First, we will show if we set a point $E$ on the segment $AC$ such that $OE=OB=OC=BC$, then $D=E$.  Becuase $\triangle{ABC}$ is a isosceles triangle, the point $O$ is on the bisecting line of $\angle{BAC}$. $\angle{OAE}=20^\circ/2=10^\circ$.   And because $OE=OC$, $\angle{OCE}=\angle{OEC}=20^\circ$, $\angle{EOA}=20^\circ-10^\circ=10^\circ=\angle{EAO}$.   Therefore $\triangle{AOE}$ is an isosceles triangle such that $EA=EO$. so $AD=BC=AE$, $D=E$.  Now we can see the point $O$ is a circumcenter of the $\triangle{DBC}$ because $OB=OC=OD.$  By using this fact, we can find $\angle{DBC}=70^\circ$,


I would like to perform some action on sliced DataFrame with multiple slice indexes. The pattern is df.iloc[0:24] , df.iloc[24:48], df.iloc[48:72] and so on with step 24 as you get it. How I can iterate it without to set it manually every time. More like df.iloc[x:z] and each iteration x=0, z=24 and next iteration with 24 step, x will be 24 and z=48 and so on. Thanks in advance, Hristo.

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


I see there are some similar questions but there's no solution there for my case. At least none that I could understand.  When I type sudo apt-get update, I get a response:  E: Malformed entry 54 in list file /etc/apt/sources.list (Component) E: Nie udało się odczytać list źródeł.   Second line means that it was impossible to read the list of sources.

I'm relatively new to Ubuntu 16.04, and everything has been going fine until my OS threw this error today.   Below is the source code from /etc/apt/sources.list for line 54:  deb http://archive.canonical.com/ partner   I have tried appending ubuntu after the / and before partner, but this does not seem to work.   Any ideas what else to try? I can't run sudo apt-get update until this is fixed.


An instructor asked me to factor $x^{2020} + x^{2019} + \cdots + x + 1$ on $\mathbb Q[x]$, which he considers to be tricky.  This polynomial is trivial to factor on $\mathbb C[x]$ and $\mathbb R[x]$. Just notice $x^{2021} - 1 = (x-1)(x^{2020} + x^{2019} + \cdots + x + 1)$ and we know  $$ \begin{equation} \begin{aligned} x^{2020} + x^{2019} + \cdots + x + 1 =&  \prod_{k=1}^{2020} \left[x - \cos(\frac{2k\pi}{2021}) - i\sin(\frac{2k\pi}{2021})\right] \\ =& \prod_{k=1}^{1010} \left[x - \cos(\frac{2k\pi}{2021}) - i\sin(\frac{2k\pi}{2021})\right] \left[x - \cos(\frac{2k\pi}{2021}) + i\sin(\frac{2k\pi}{2021})\right] \\ =& \prod_{k=1}^{1010} \left[x^2 - 2\cos(\frac{2k\pi}{2021})x + 1\right] \end{aligned} \end{equation} $$  It's not easy to "combine" the factorization over $\mathbb R[x]$ to form a factorization over $\mathbb Q[x]$ though.  Should I go the other ways and try to prove it's irreducible? Maybe not. Since $2021 = 43 \times 47$, it seems reducible.

I studied the cyclotomic extension using Fraleigh's text.   To prove that Galois group of the $n$th cyclotomic extension has order $\phi(n)$( $\phi$ is the Euler's phi function.), the writer assumed, without proof, that $n$th cyclotomic polynomial $\Phi_n(x)$ is irreducible over $\mathbb{Q}$.  I know that for n=p, p is prime, $\Phi_n(x)$ is irreducible over $\mathbb{Q}$ by Eisenstein's criterion.  But I don't know how $\Phi_n(x)$ is irreducible over $\mathbb{Q}$ when n is not prime.


How to create frames as shown below with tcolorbox package. Although I did learn about it but did not know how to create the begging you help me thanks!

I would like to clone this box used on the tcolorbox manual, but I couldn't find the configuration in the manual.    Can you help me?


I have json string which looks like the following:   "users":[       {user_id=1,        user_name=foo,        profile_image=profile.png},       {user_id=2,        ............},        .............           ]   How can I convert it into a java arraylist of key,value pairs?

What is the best way to convert a JSON code as this:  {      "data" :      {          "field1" : "value1",          "field2" : "value2"     } }   in a Java Map in which one the keys are (field1, field2) and the values for those fields are (value1, value2).  Any ideas? Should I use Json-lib for that? Or better if I write my own parser?


Let $R$ be a commutative ring with unity such that every prime ideal contains no non-zero zero divisor (i.e. if $P$ is a prime ideal and $x,y \in P$ with $xy=0$ then either $x=0$ , or $y=0$). Then is $R$ an integral domain ? (I want every prime ideal $P$ to contain no non-zero divisor as a ring in it's own right, not that $P$ contains no non-zero divisor of $R$.)    This question is related to , but is not exactly same.   Please help. Thanks in advance.

Let R be a commutative ring, and let P be a prime ideal of R. Suppose that P has no nontrivial zero divisors in it. Show that R is an integral domain.   My proof:  Take $r,s,a \in R$ with $ar = as$, and $p \in P$. Then  \begin{align*} par &= pas\\ a p r &= a p s && \text{R is commutative} \end{align*} and since $P$ is an ideal of $R$, then $pr, ps \in P$. Since $P$ is an integral domain, then $a p r = a p s \implies p r = p s$, so $r = s$.  I'm not using the fact that $P$ is a prime ideal which leads me to believe that I messed up a step.


I started a bounty at 11:52 on Nov. 7th and it expired yesterday after seven days. No answer has been posted and I know I will end up losing this reputation.   Now, it is 12:12 on Nov. 15th, eight days and 20 minutes passed since I started it. But I still see the message below:     I understand the purpose of this message.   How long is as soon as possible? Is this message or extension useful when there is no answer?   Note: The reason I asked this question was this grace period is blocking me from starting another bounty. When there is no answer, I don't see any usefulness of this grace period or message.

The bounty I offered on  is now in its grace period and the information box tells me:     you must award this bounty as soon as possible   But there are no answers - what do I do?


I want to convert the output of ls to octal permission bits.  I think of the shortest and clearest way to implement that excerise: Let's say that we have as input:  total 1 drwxr----x 1 user2 workers 1024 May 26 22:22 dir -rwx-wxrw- 2 user2 workers 1024 May 26 22:22 file.txt   our output should be:  741 dir 736 file.txt

Say I have the following output from ls -l:  drwxr-xr-x 2 root root 4096 Apr  7 17:21 foo   How can I automatically convert this to the format used by chmod?  For example:  $ echo drwxr-xr-x | chmod-format 755   I'm using OS X 10.8.3.


I am new in Blender and  I can't understand why rendering goes wrong?

While rendering a mesh with smooth shading on, I get a dark region/shadow on certain faces. The effect is more evident when smooth shading is applied to a mesh containing ngons, with the ngons turning black when rendered.   The blackening effect is visible in the viewport too.  How can I solve this problem?


I'm trying to use natbib in a manuscript draft using the document class nature. If I use the bibliography style naturemag, any citation I try to use with \citet{something} does not turn up correctly, and is given a missing author.  Is there any way to solve this, or is the naturemag bibliography style incompatible with \citet citations?

I'm trying to compile my bib references with natbib and \bibliographystyle{nature}. To my uttermost surprise BibTeX reports that some of the entries have an empty title, while IMHO the title is not empty, e.g., on the following bibliographic entries:  @INPROCEEDINGS{WuWangZhaoMa, author={Wu Kehe and Wang Zhuo and Zhao Xing and Ma Gang}, booktitle={Advanced Computer Theory and Engineering (ICACTE), 2010 3rd International Conference on}, title={Design and implementation of the monitoring system for EJB applications based on interceptors}, year={2010}, month=aug, volume={4}, pages={V4-5--V4-9}, ISSN={2154-7491}, location = {Chengdu, China} }   and  @inproceedings{DBLP:conf/sigdoc/TilleyH03,   author    = {Scott R. Tilley and                Shihong Huang},   title     = "A qualitative assessment of the efficacy of {UML} diagrams                as a form of graphical documentation in aiding program understanding",   booktitle = {SIGDOC},   year      = {2003},   pages     = {184--191},   ee        = {http://doi.acm.org/10.1145/944868.944908},   crossref  = {DBLP:conf/sigdoc/2003},   bibsource = {DBLP, http://dblp.uni-trier.de} } @proceedings{DBLP:conf/sigdoc/2003,   editor    = {Susan B. Jones and                David G. Novick},   title     = {Proceedings of the 21st annual international conference                on Documentation, SIGDOC 2003, San Francisco, CA, USA, October                12-15, 2003},   booktitle = {SIGDOC},   publisher = {ACM},   year      = {2003},   isbn      = {1-58113-696-X},   bibsource = {DBLP, http://dblp.uni-trier.de} }


I use nano <file_name> to open/edit files on my remote Digital Ocean server (running Ubuntu 16.04). However it's very hard to edit so is there a way to open these files in TextEdit?  I tried to use the proposed solutions below but they do not work:  open -a TextEdit <my_file_name> and open -a TextEdit both return this:  open: invalid option -- 'a' Usage: open [OPTIONS] -- command  This utility help you to start a program on a new virtual terminal (VT).  Options:   -c, --console=NUM   use the given VT number;   -e, --exec          execute the command, without forking;   -f, --force         force opening a VT without checking;   -l, --login         make the command a login shell;   -u, --user          figure out the owner of the current VT;   -s, --switch        switch to the new VT;   -w, --wait          wait for command to complete;   -v, --verbose       print a message for each action;   -V, --version       print program version and exit;   -h, --help          output a brief help message.   open -e <my_file_name> returns:  Couldn't get a file descriptor referring to the console   so I tried an alternate method I found.  I added alias textedit='open -a TextEdit' to my .profile. After that I tested it with textedit settings.py and it returned  The program 'textedit' is currently not installed. You can install it by typing: sudo apt install xview-clients   So I installed it - but after I tried textedit settings.py again, it returned:  XView error: Cannot open connection to window server: :0 (Server package)   Any idea?

I wanted to try out using graphical tools over ssh. Just to learn a new thing :)  so my understanding is this, I connect like this: ssh -port -x user@server  But I'm running ubuntu server so it has no gui and thus no gui tools. My understanding is I've to install gedit on server. But also xserver?  Can someone clear up this concepts to me?


I know someone asked this question before  but it still doesn't make any sense for such a property! I looked into the source code of the Array class on  As you can see from source code, all methods related to finding a specific index, for example:  public static int LastIndexOf<T>(T[] array, T value)   return integer value System.Int32, So again, What is the point of a property which returns a System.Int64 representation of an array length but all the other methods that deal with internal item indices return System.Int32? This is really confusing!

What is the purpose of the LongLength property for arrays in .Net.  Using a standard integer for length, you could accommodate up to 2 billion indices.  Are there really people using .Net to maintain a single array with more the 2 billion elements.  Even if each element was a single byte, that would still be 2 GB of data.   Is it feasible to use such a large array in .Net?


I want to set up a folder such that anything created within it (directories, files) inherit default permissions 777. Can we set a umask for a particular directory to achieve this?

I have a /data folder (actually a partition) for all data that should be accessible by all users (in this case family members). We all have individual user accounts and are often all logged in at any time on this one PC.  How can I set up permissions so that we all retain access to files there no matter who creates them, including new folders? If I create a folder it gets my user and group, so nobody else can write to it.


The following code  \documentclass{amsart} \usepackage{fontspec} \usepackage{unicode-math} \setmainfont{Minion Pro} \begin{document}   \title{A motif approach to the Mordell conjecture}   \author{Shurik G.}   \maketitle \end{document}   compiles differently with XeTeX:  and LuaLaTeX:  Why does LuaLaTeX produce the title in italic? How can one solve the problem keeping the LuaLaTeX engine? I checked that LuaLaTeX works correctly with other fonts, including Cambria. TeXlive 2016 with updates, Linux x86_64.

When I compile with LuaLaTeX and TL2016 this MWE   \documentclass{article}  \usepackage[no-math]{fontspec} \usepackage{luatex85} \usepackage{shellesc}  \setmainfont{Minion Pro}  \begin{document}  \huge{huge} \textbf{\huge{huge}}  \Huge{Huge} \textbf{\Huge{Huge}}   \end{document}   I have this .pdf.     Any help? With TL2015 all is correct. Thanks


Quick question of the order between enemy actions and friendly reactions.  Sentinel  When a creature within your reach makes an attack against a target other than you (and that target doesn't have this feat), you can use your reaction to make a melee weapon attack against the attacking creature.   Does this happen before the enemy's attack goes through? So the player have a chance to kill the attacking creature before he attacks the players party member? Or does the enemy's attack connect first, giving the player an opportunity to attack the enemy?

The third benefit of the Sentinel feat (PHB, p. 169-170) allows a melee attack when an enemy within 5 feet of you makes an attack against a target other than you (that doesn't have the feat).   If you kill this enemy with your attack, does their triggering attack still go through?  Same question if say you knock him back or prone, etc.


Is there any case in the Harry Potter-verse of someone magic born but having no magic skills? I haven't read enough to know why muggleborns can have magic powers but if it works one way then maybe the other?

I just started re-watching the Harry Potter series, and I had a curious thought.  We know that Harry was born to two parents who were capable of magic, and is able to to do magic. We know that Hermione was born to two Muggle parents, and can also do magic.  Is there anybody born to two magical parents, who is unable to do magic themselves?


Are these the correct constructions?   Do any of the students write well? Does anyone write well?

I always thought with "any" I should use the plural, but on the internet I can find both:   It can be found in any book. It can be found in any books Do you have any books? It can be said in any language.  This can be understood by anyone.  It has been used in any form.   So, what's correct?  Is there any rule?


What is the difference between these?   #hello-world p  p #hello-world  p#hello-world  If you could give me an example of each that would be the best. Thanks

What's the difference between
 and
 when it comes to CSS? Is it alright to use
?  I see different developers doing this in both ways, and since I'm self taught, I've never really figured it out.


does frozen vegetables and berries need to be washed or rinsed before cooking for eating fresh? Frozen vegetables and berries do you keep them in the freezer or chiller or in an airtight container to stay fresh?

Do frozen vegetables have pesticides on them? Are you supposed to wash frozen vegetables before you cook them and eat them?


Given a matrix A, return the transpose of A. The transpose of a matrix is the matrix flipped over it's main diagonal, switching the row and column indices of the matrix. Example Input: [[1,2,3],[4,5,6]] Output: [[1,4],[2,5],[3,6]] my code: def transpose( A):     length = len(A)     width = len(A[0])     res = [[0] * length] * width     for i in range(length):         for j in range(width):             res[j][i] = A[i][j]     return res        transpose([[1,2,3],[4,5,6]])  my code's result : [[3, 6], [3, 6], [3, 6]] I track in the double loop, every time the res is updated, the value of a column is updated. def transpose( A):     length = len(A)     width = len(A[0])     res = [[0] * length] * width     for i in range(length):         for j in range(width):             res[j][i] = A[i][j]             print(i,j,'->',j,i)             print(res)     return res        transpose([[1,2,3],[4,5,6]])  The output information is as follows: 0 0 -> 0 0 [[1, 0], [1, 0], [1, 0]] 0 1 -> 1 0 [[2, 0], [2, 0], [2, 0]] 0 2 -> 2 0 [[3, 0], [3, 0], [3, 0]] 1 0 -> 0 1 [[3, 4], [3, 4], [3, 4]] 1 1 -> 1 1 [[3, 5], [3, 5], [3, 5]] 1 2 -> 2 1 [[3, 6], [3, 6], [3, 6]]  But the following code gets the correct result： def transpose( A):         length, width = len(A), len(A[0])         res = [[0] * length for _ in range(width)]         for r, row in enumerate(A):             for c, val in enumerate(row):                 res[c][r] = val         return res  transpose([[1,2,3],[4,5,6]])  It's confusing!Is there any difference between the two ways of loop？ Is it caused by the underlying code optimization during compilation?

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


For the Fourier transform defined as $$\frac {1}{\sqrt{2\pi}} \int_{-\infty}^\infty f(x) e^{-i\alpha x}\,dx$$ I know there is simple formula for the Fourier transformation and inverse transformation of $$f(x)=e^{-x^2/a}$$ but I can't remember it or derive it on my own.  Does anyone have a formula for this?

I need to calculate the Inverse Fourier Transform of this Gaussian function:  $\frac{1}{\sqrt{2\pi}} exp(\frac{-k^2 \sigma^2}{2})$  where $\sigma > 0$, namely I have to calculate the following integral: $\int{\frac{1}{\sqrt{2\pi}} \exp(\frac{-k^2 \sigma^2}{2})} \exp(ikx) dk$.  How can I do that? If I am not wrong (in which case please correct me) the result should be $\frac{1}{\sqrt{2\pi}\sigma}exp(\frac{-x^2}{2\sigma^2})$...but I don't know how to get there!


Yoneda Lemma says that, for a locally small category $\mathcal{C}$, an object $A$ in $\mathcal{C}$ and a functor $F:\mathcal{C}^{op}\to \textbf{Set}$, the natural transformations $[Hom(-,A):F]$ is in one-to-one correspondence with elements of $F(A)$.   My question is the following:   $\textit{A priori}$, we do not know that the collection $[Hom(-,A):F]$ is.  Now we show a "bijection" to $F(A)$.  How does it imply that the collection $[Hom(-,A):F]$ is a set.    If the above question does not make sense, then I try to frame it in another fashion.    For doing mathematics we need to consider primitive undefined objects and their "properties".  Mathematicians argue that foundations can be built in many ways like-   sets and $\in$ (Well, wasn't this the plan) sets and $f$ (function) (Leinster's $\textit{Basic Category Theory}$) types (friend told this to me)    So what are the objects we are considering in Category theory. If we take an arbitrary collection of morphisms, when can we say it is a set or not.  If it is not a set, how is its properties different from that of a set.   If this is vague question, specfically considering Yoneda Lemma, how can we say that $[Hom(-,A):F]$ is a set.

Appearing on the second page (under the section Digression: Size worries) of the following paper about the Yoneda Lemma:     It says that $a$ $priori$ $[\mathcal C^{op},Set](H_A,X))$ is a class. I don't understand why this is the case.  My understanding is that $a$ $priori$ each member of $[\mathcal C^{op},Set](H_A,X))$ is a class.  So it seems to me that $[\mathcal C^{op},Set](H_A,X))$ could be a collection of proper classes.  I've looked at this , but it hasn't helped me much.  Any help is appreciated -Thanks


How do I show that $\mathbb{Q}[X]/(X^2 + X + 1)$ and $\mathbb{Q}[X]/(X^2 + 1)$ are not isomorphic?

I found an argument online that the two fields are not isomorphic but I can't make sense of the argument. You find it .  These are the things I'm confused about when it comes to the argument.     It says that the field $\mathbb Q[x]/(x^2+1)$ contains a root of the polynomial $x^2+1$. I suppose this is the congruence class $[x]$? But this is not the same as the zero element of the field $\mathbb Q[x]/(x^2+1)$, right?   It says that every isomorfism takes $0$ to $0$. I interpret this as the zero-element in $\mathbb Q[x]/(x^2+1)$ (which I interpret to be $[0]$) is taken to the zero-element in $\mathbb Q[x]/(x^2+2)$ denoted $[0]_2$. But in the argument it says that this means that if $\mathbb Q[x]/(x^2+1)$ has a root of the polynomial, then also $\mathbb Q[x]/(x^2+2)$ must have a root of this same polynomial. Why is that?     Greatful for any help!


Some newer Samsung devices have a pull out tab that stores some of the commonly used applications. I have accidentally enabled and disabled it a number of times, but I don't know how. I don't see anything related to it in device settings or any of the installed apps that would control it.  How do you hide / show this pull out bar?      (Click on the image for larger version)

A couple of weeks ago a sliding app section appeared on my home-screen. I have no idea how it got there, and no clue on how to disable/remove it. I tried all I could on the homescreen, to no luck.  Using Galaxy S3, Android 4.1.2, everything standard (so no custom launcher).    Any ideas on how to remove it?


I am not talking of a  style , but am I or anyone else allowed to comment in a question of mine requesting an answer from a particular person? Example,  Persons_name I would really appreciate an answer from you.  OR  It is an area of expertise of Persons_name and I would appreciate an answer from him/her.  OR  This question maybe best answered by persons_name  The reason being that particular question might be a speciality of that person.  The necessary assumption should be that:  it's a very new question, that particular person is a frequent visitor who also sees almost every question, so there is a good chance that he/she will probably see the comment, He/she hasn't yet commented in any part of the question and its existing answers (if any). The Stack Exchange site is not Stack Overflow, hence the maximum questions per day is 15.

There has been quite a few times that I wished I could send a message to another user on SO - not ask a question for everyone to see, but just a short message informing them of something or requesting them to do something.  Are there any plans to allow this to happen in the future?  Related:


I am currently using Ubuntu 15.04 and wish to upgrade to 16.04 LTS. I try:  sudo do-release-upgrade   But I get:  Checking for a new Ubuntu release No new release found   How do I move forward? Is my install simply reporting the wrong version number - how can I find out?  I mean, it looks like I am still on 15.04  lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 15.04 Release:    15.04 Codename:   vivid   What next steps can I take?  UPDATE  I followed the directions in  which caused a lot of 404 errors. I then realised that vivid was not in  and search replaced those urls back to  and, bingo, updates working as they should.  TL;DR: The sources list was clearly wrong. Fixed it.

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


How can I configure the ↑ key to get commands from history?  Example: If I type p and press ↑ then it should only show commands in the history starting with "p" like python, php, perl, etc.  Please can anyone help me to configure this feature?  I've edited .bashrc, but it doesn't work for me.

I have searched, but not found anything on this. I am looking for a functionality in bash, using a terminal.  Way back when, I had a user on a debian system, and a friend set me up with a convenient history search feature (I believe I used tcsh then), where I would type the beginning of a previous command, hit up-arrow, and it would do a search, based on the partial string.  E.g. if my history is:  ./script.pl ./script.pl arg1 cat output cat output | grep yada   And I type ., and press up-arrow, it would show me: ./script.pl arg1. Press it again and it would show ./script.pl, etc.  Very much like it would perform a grep on .bash_history. Is there a way to get this functionality?


Problem  Let $f:\mathbb{R}→\mathbb{R}$ be a differentiable function such that $f(0)=0$ and $\forall x \in \mathbb{R} \enspace f′(x)=[f(x)]^2.$  My Process  I want to solve this question with analysis arguments, not simply ODE. This question is in the integral chapter so maybe we should use that.  Anyways. A method that would work would be to show that as $f$ is continuous, the set of points where $f \neq 0$ is open. If we then show that this set is also closed, it would have to be the empty set since as $f(0)=0$, it can not be $\mathbb{R}$. The thing is I cant see how to show this.  Also, is there another way, actually using integrals?

Let $f:\mathbb{R} \rightarrow \mathbb{R}$ be a differentiable function such that $f(0) = 0$ and $f'(x) = [f(x)]^{2}$, $\forall x \in \mathbb{R}$. Show that $f(x) = 0$,  $\forall x \in \mathbb{R} $.  I first (unsuccessfully) tried using the Mean Value Theorem, but this is in the Integrals chapter so the solution probably involves them. Can't really see where integrals come in here though.  What I've got so far:   (i) Since $f$ is differentiable, thus it is continuous and, hence,  integrable. Therefore $f^2$ is also integrable and as $f'=f^2$, $f'$ is too.   (ii) $f' \geq 0$, $\forall x \in \mathbb{R}$


i have a TextView which is set using...  // Declare view variables private TextView mInfoText;  // Assign views from layout file to cor. vars mInfoText = (TextView) findViewById(R.id.infoText);   how do i do an if else statement for the text inside it, i thought about doing it like this, but it doesn't work, i get a red line under the word "Sand".  if (mInfoText = "Sand"){                  //Show correct              } else {                  //Show incorrect             }   Any ideas?

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


I would like to know where I could find an installer for MiKTeX embedding all existing LaTeX packages (if it exists). I am going to install LaTeX on a computer which will not ever be connected to Internet, and which won't allow amovible media (USB key/CD-ROM/...) as soon as everything is set up. So basically, I have to do a "one-shot" installation. I still do not know my needs in term of LaTeX packages, so I am wondering if a version of MiKTeX embedding all existing LaTeX packages existed.   I would like to install it on a Windows computer.

As I understand it, a snapshot of the MiKTeX/TeXlive is available on .  How do I install a complete (with all packages) TeX distribution on an offline computer (without Internet) ? Is MiKTeX/TeXlive snapshot available on a DVD (for a price)/free or on some "TeX user groups"?  Is the MiKTeX/TeXlive snapshot available for free for download? If so, where can I find it?


Since the definition of Cauchy sequence is: , I noticed we need an absolute value for $a_m-a_n$ in the definition so the statement would be false. But I can't find such a couterexample. Maybe it is true?

What is an example of a sequence in $\mathbb R$ with this property that is not Cauchy?  I know that Cauchy condition means that for each $\varepsilon>0$ there exists $N$ such that $d(x_p,x_q)<\varepsilon$ whenever $p,q>N$.


I have this DEM file that's I've colored by altitude.   When I try to do a hillshade on this DEM I get some contouring and very dark shading.   Could someone give me a hint as to what I need to correct?  When I use the Processing Tool in the Raster Analysis Menu I get a similar result.  Ultimately I want to use multishading, but when I check that on it goes all black.

I have a problem with hillshade function: I've set 315 azimuth, 45 vertical angle and 1 Z factor, but the result is very bad...  The original dem file is a .geotiff from Global Data Explorer (Aster Global DEM V2). I would like to obtain a pretty hillshade, but I don't know what is wrong.  Here the original and the screen of the hillshade result. It's 1:660.000 scale


When I get to distribute exp to party members, should I give the same amount of EXP to everyone or split it by monsters killed/fight contribution?

I am a very inexperienced DM. I have here what must be an obvious question, but I can't seem to find any solid clarification.  How is XP rewarded after a combat encounter? Is the total monsters' XP given to each player, divided between the players, awarded depending on which player killed each monster, or something else?  Or can anyone recommend discarding the XP system altogether and levelling up everyone when appropriate? If so, how exactly should that work?


Similar to  question but replace produce flame with a missed melee attack with green-flame blade.  If I cast green-flame blade but miss the melee attack with the weapon, does the benefit of Flames of Phlegethos still trigger?  I would think the answer is also yes but I just wanted to make sure I'm not making a logical jump.

I have a player in my campaign who took the  tiefling racial feat (from Xanathar's Guide to Everything, p. 74-75). One of its abilities is:     Whenever you cast a spell that deals fire damage, you can cause flames        to wreathe you until the end of your next turn. The flames don’t harm        you or your possessions, and they shed bright light out to 30 feet and        dim light for an additional 30 feet. While the flames are present, any        creature within 5 feet of you that hits you with a melee attack takes        1d4 fire damage.   Additionally, he took the  cantrip:     A flickering flame appears in your hand. The flame remains there for        the duration [...]      You can also attack with the flame. When you cast this spell, or as an        action on a later turn, you can hurl the flame at a creature within 30        feet of you. Make a ranged spell attack. On a hit, the target takes 1d8        fire damage.   If he casts the produce flame cantrip and holds it (i.e. doesn't attack or attempt to deal damage with it) would that still trigger this Flames of Plegethos ability?


I need to show that $\{(x,y,z)\in\mathbb{R}^{3}:x^2+y^2+z^2 = 1\}$ is connected. Intuitively I understand that it is path connected and, therefore, connected. However, I don't understand how I would define such a path mathematically. For example, if I wish to show that every point on the unit sphere connected to the north pole and, therefore, to every other point, how would I show this?

I am asked whether the unit sphere $$X=\{(x,y,z,w)|x^2 + y^2 + z^2 + w^2 = 1 \}\subset \mathbb{R}^4,$$ is path connected or not. I just know that $X$ is a closed subset. How can I answer this question? Is there any hint? Thank you very much.


I need to take the token and username out of a url to store as a variable in my code for MVC. The URL is   local.test.test.com/Login/PasswordReset?u=test.hitt@emp.test.com&t=5cd5acc2-2446-47fb-862d-7a13871aa523   The username would be: test.hitt@emp.test.com The token being: 5cd5acc2-2446-47fb-862d-7a13871aa523  I currently have what is below, but am getting a null value.    string userName = Server.UrlDecode(Request.QueryString["u"]);  string userToken = Server.UrlDecode(Request.QueryString["t"]);

Under ASP.NET MVC are you supposed to pick up QueryString params the same way you do in ASP.NET WebForms? or does the [AcceptVerbs(HttpVerbs.Get)] declaration get used somehow?


I'm not sure if it is a .Net or C# or even Visual Studio 2010/2008 thing, but I noticed that whenever I pause my application to change something in the code and the changes are made within a delegate, I can't resume the application but have to restart it.  So my questions are:  1) Is this depend on the programming language? Or the framework? Or the Editor?  2) Is it only when I change delegates? Or other things?  3) Why is this so?

So, every time I have written a lambda expression or anonymous method inside a method that I did not get quite right, I am forced to recompile and restart the entire application or unit test framework in order to fix it. This is seriously annoying, and I end up wasting more time than I saved by using these constructs in the first place. It is so bad that I try to stay away from them if I can, even though Linq and lambdas are among my favourite C# features.  I suppose there is a good technical reason for why it is this way, and perhaps someone knows? Furthermore, does anyone know if it will be fixed in VS2010?  Thanks.


I want to delete everything related to libreoffice. So I did a: sudo apt remove --purge libreoffice* But it's telling me that: E: Unable to locate package libreoffice*  I'm not exactly sure what obvious issue I'm missing here.

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


I have read several threads and articles about the need to use nested cross validation when, for example, choosing between different machine learning algorithms. Here are two describing the use of nested cross validation in algorithm selection: , .   I am aware that the process of nested cross validation in selecting between, for example different algorithms, is as follows (for the case of k fold CV):   The inner loop CV uses the 'outer loop' training sets, to find the optimal hyperparameter. The optimal hyperparameter is chosen based on its test performance on the 'inner loop' test folds. Here we loop over a selection of different hyperparamter values. If we performed 5 fold CV in the inner loop, then each hyperparameter's 'score' is the average of the scores from testing it on the 5 'inner loop test' folds.  The 'inner loop' gives us our best hyperparameter. We then train a model on the 'outer loop' training data (which we earlier split inside the 'inner loop') and calculate its test performance on the 'outer loop' test fold.  This entire process is repeated for as many 'outer loop' folds we are using. So, if we were doing 5 fold 'outer loop' CV, we could (depending on model stability) end up with 5 different hyper parameters.   Once this is repeated for these 'outer loop' folds, we take the average of all the 'outer loop' test fold scores to get the overall test performance of that particular algorithm. This is repeated for all the algorithms we are comparing. The one with the best score is taken forward.    I know the purpose of separating the model selection (done in the inner loop) and performance estimation (done on the outer loop) is to avoid biasing the results somehow, but i don't understand why. I have looked at several threads on here but cant get my head around it (e.g.  , )  Take the following example of where normal (say 5 fold) cross-validation is used. This would involve the following steps:   Split data into 5 folds Select the first algorithm to test. Take a given value form the selection of hyperparameter values we wish to test, and train it on the 4 training folds. Calculate a test score using the remaining test fold. Repeat for all 5 folds. Average all 5 test scores to get the average test score for that hyperparameter.  Repeat this for all values of the hyperparameter. The one with the best test score is carried forward.  Repeat this for all the algorithms we wish to test. Compare the average test scores for each algorithm and the one with the best test score gets carried forward.   I can't seem to understand why the above method, which doesn't require nested cross validation is not sufficient?  I guess the question is, why do we need to separate the model selection and performance estimation steps into the inner and outer loops? I can't see the benefits of this compared to doing both at the same time, which is what the second set of steps described does.  UPDATE I've come across a video which explains the reasoning very well:

How can one use nested cross validation for model selection?   From what I read online, nested CV works as follows:   There is the inner CV loop, where we may conduct a grid search (e.g. running K-fold for every available model, e.g. combination of hyperparameters/features) There is the outer CV loop, where we measure the performance of the model that won in the inner fold, on a separate external fold.    At the end of this process we end up with $K$ models ($K$ being the number of folds in the outer loop). These models are the ones that won in the grid search within the inner CV, and they are likely different (e.g. SVMs with different kernels, trained with possibly different features, depending on the grid search).  How do I choose a model from this output? It looks to me that selecting the best model out of those $K$ winning models would not be a fair comparison since each model was trained and tested on different parts of the dataset.  So how can I use nested  CV for model selection?   Also I have read threads discussing how nested model selection is useful for analyzing the learning procedure. What types of analysis /checks can I do with the scores that I get from the outer K folds?


Why do the Natural Earth shapefiles like ne_110m_countries_admin_0.shp have a geometry-type POLYGON, while it should be MULTIPOLYGON (at least when I understand  correct. E.g. USA48 + Alaska + Hawaii is Multipolygon)

Creating Scratch layer gives me a choice between Polygon and Multipolygon, so I started wondering how should I make use of them.    Reading a new book "Mastering QGIS" (through  by Joseph to ), authors' comment was "ESRI shapefiles store geospatial data in multi- type geometry, so using multi- type geometry is a good practice if you plan on converting between formats."  How should I choose one of them (Polygon or Multipolygon) when I create a new polygon layer? (I had confused multi-polygon with multipart-polygon, so I used to choose Polygon.)      One recent situation I have come to choose Polygon/Multipolygon was  in which I draw a dummy polygon as a background layer. Working mainly on shapefiles it seemed I was supposed to choose Multipolygon, although I needed only one polygon. In this case what I needed was simple polygon geometry without any attribute (Not sure this example make any distinction.)


I'd like to press, for example, the Menu key and the output be as if I pressed Ctrl+R or another combination of keys. In other words, I'd like to set aliases for combos using the same graphical user interface (System Settings/Keyboard menu) provided by Ubuntu 16.04 to set/change keyboard shortcuts. Thanks in advance!  LE: I do not want to install Autokey, I want a builtin functionality as I already mentioned above. In plus, Ctrl+R does one thing inside a browser window and another thing inside a terminal window. I just want, for example, to press Menu key and Ubuntu to think I pressed Ctrl+R. That's all. I hope I was clear enough. Just a suggestion.

I want to change the key bindings on some of the keys on my keyboard.  I want some to run commands and others to activate different keys.  What applications can I use to do this?      Index:       (from within System Settings)             I'm still looking for answers using dconf and any other method.


I am trying to write a program that could catch user input of string type. Every time there is a space within this string, the program needs to get that part of the string and try to parse it to a decimal. The entries might be numbers that might be separated by a comma rather than just plain integers, that is why I would be using decimals instead of integers.  This is what I tried so far:  static void Main(string[] args) {     Console.WriteLine("C# Exercise!" + Environment.NewLine);     Console.WriteLine("Please enter two numbers seperated by space to start calculating: ");     string[] input = Console.ReadLine().Split(' ');     //Currently allows for more than one value... I am not necessarily looking for a solution to this problem however.     Console.WriteLine(Environment.NewLine + "Result: ");     //Create the collection of decimals:     decimal[] numbers = { };     numbers[0] = 1.0m;//<-- Results in a System.IndexOutOfRangeException     for (int i = 0; i < input.Length; i++)     {         Console.WriteLine(input[i]);//<-- This value needs to be converted to a decimal and be added to a collection of decimals     }     /*decimal numberOne = ?? //<-- First decimal in the collection of decimals     decimal numberTwo = ?? //<-- Second decimal in the collection of decimals     Console.WriteLine(SumTrippler.Calculate(numberOne, numberTwo));*/     Console.WriteLine(SumTrippler.Calculate(decimal.Parse("0.5"), (decimal)0.5));//<-- Irrelevant method     Console.ReadKey(); }   How could I get two decimals as user input from the user and process this data by passing it to the method at the bottom of my program?  Edit: Closing this question because you are trying to relate a question that adds a string to a list is not a solid reason. I am not trying to add a string to a list.

How to add new item in existing string array in C#.net?  I need to preserve the existing data.


Do American movie theaters really have the intermission for Indian movies or do they skip it?   Like: Indian movie theater do have an intermission for . But do US theaters have an interval for the same movie as well?  My Question is different from this . I am not asking whether film industries outside India use intermissions. My question is about intermission taken for Indian movies by US theaters.

I have seen classic English movies with intervals/Intermission. Current Indian movie industries (Bollywood and others) use intervals and theaters introduce intervals in current English films by interrupting them. Are there other film industries who use intervals?  I am not asking about just theater practices. Movies often change tone after the interval so movie reviews compare both "halves". For example the first half of a movie may evoke laughter all the time while the second half is dead serious.


I have recently acquired a used Nikon D3000 and I've noticed its lcd has dark corners. Seems to have a spotlight in the center of the lcd though it's not affecting the actual image when opened in laptop. I just want to know what's causing this as this might be an issue that can affect other parts of the unit in the future. I've aso looked around the settings for possible configuration but can't find any and also can't find a related thread over the internet.  Please see pic below.

I have a Nikon D7000. The rear LCD is showing some dark shadows. All four corners have this dark shadow but the shadows on upper and lower corners on the right side of the LCD is bigger. At first I thought it's a lens issue then I changed the lens and it's the same. Live view is pretty alarming with these corner patches.   My images are not affected by this dark shadow. I even tried removing the hood/filter. What could be the reason behind this problem and is there any way to solve this?  If anyone has faced the same issue, is there any solution or advice??


Is it valid to use / in a class name in html/css?  // html

  // css ./10{ float:left; }

What characters/symbols are allowed within the CSS class selectors? I know that the following characters are invalid, but what characters are valid?  ~ ! @ $ % ^ & * ( ) + = , . / ' ; : " ? > < [ ] \ { } | ` #


I'm a non-U.S undergraduate Computer Science student and I want to get admission from an eminent U.S university for M.Sc./PHD.    In my experiences, there are lots of practical records. From about 10 teaching assistantships (well I call it practical in comparison to publishing papers for example) and holding programming workshops to doing valuable professional projects, for example a noticeable social networking website which is of course related to my field of study and the fields I'm interested to continue to study and do research in M.SC./PHD.    But I don't have any publications and my GPA is about 2.8/4.0 .  I'm afraid if my CV seems to be more "practical" than "academic" and maybe admission offices of eminent universities are looking for more academic prospective students.    1- Now what's your opinion about this situation and my chance to get admission from eminent U.S universities? 2- From an academic professor's point of view, which is more valuable for an undergraduate student: having publications or making such projects or teaching experiences?

When applying to a PhD program in the US, how does the admissions process work? If an applicant is weak in a particular area, is it possible to offset that by being strong in a different area?  Note that this question originated from this . Please feel free to edit the question to improve it.


I need to write a title of a section that is a list of deals. The title could be "List of deals" but I prefer a more concise form. Since there are usually a lot of deals in the list is it correct to use a title like "Deals list" or should I write "Deal list"?

How can I explain to a non-native speaker that while this is correct:     The felling of trees.    And this is also correct:     tree felling   This is not:     *trees felling   To a non-native it seems very reasonable that since many trees are being felled and given that the felling of trees uses the plural, the inverse form would also use the plural and become trees felling.  To a native speaker such as myself, the latter is very obviously wrong, but I couldn't figure out how to formalize this into a rule that a non-native can understand.


how much helium would you need to pick up one kilogram on mars? is there an equaison that can be used?  thnx alot!

How much lift does the average helium filled party balloon produce? (not including any extras like ribbon string)


Is anyone aware of it ever having been addressed that for a technology such as beaming to remove an object from an environment that is not a vacuum, that on removing it, there would be an instant collapse of a vacuum pocket where the object used to be. The inverse of that would be, provided that one was not "beaming the air out" then I would assume it gets pushed aside. If all this happens at any rate of high speed relating to that of electrons/photons one would have to guess that it causes at the very least a lot of noise...  One would think for this type of technology to work, there would have to be some sort of spatial pre/post processing. Likewise since the locations could and most likely would be moving in relation to one another (say if you were beaming to a planet from a space ship) if the source were not statically bound to the same physical / gravitational grasp (such as on the same planet) that it would not only have to be prepped ahead of time, but sustained and tracked at a potentially very fast rate. The theory could even be weaponized, imagine if someone were to “beam” all the air out of a large building relatively instantly… or beam up a few cubic miles of dense atmosphere just to the left of a ship in orbit, how about a few tons of solar plasma onto a bridge? Matter is matter in that regard, but I digress… There are things like Heisenberg compensators and inertial dampeners mentioned, has this seemingly obvious problem ever been directly addressed, and if so does anyone know of any specific show /. Episodes that did?

A fundamental law of physics is, in short, that two things cannot exist in the same space at the same time.  This is easily demonstrated by dropping a relatively large mass, such as pasta noodles, into a container of water, such as a pot.  The water level will rise as it "makes room" for the pasta, and will overflow if you've put in too much of either.  Conversely, if you were to scoop all of the noodles out (presuming you had a way to scoop just the noodles, without taking along any water at all) you would see the water sink down to its original level (or lower, if it had overflown earlier).  Taking this into consideration, I see a problem with transporter technology which I'm not sure I've ever seen addressed:  What happens to the air surrounding a transport subject's origin point, or occupying the destination?  The transporter must have some means of compensating for the displacement, otherwise each transport should in theory be accompanied by a loud pop at each end - at the origin when the air collapses to fill a vacuum left behind, and at the destination when a relatively large volume of air is forced away to make room for the subject.  This effect should be even more pronounced, and perhaps even hazardous, in closed environments such as spacecraft where the air has really no place to go.  One option would be to have the transporter exchange the air (or other matter, such as dust or raindrops) at the destination for the matter of the subject, as it is being transported.  However, this is not seen as we would often notice small portions of dust storms or downpours getting dropped onto the transporter pad when people are transported into adverse weather conditions.  Imagine having that cleanup as part of the Transporter Chief's job duties.  Another option would be to process the matter from the destination through the replicator, so that it is congruous with the same volume of air at the origin.  This would be a fairly complex operation though, and could result in a lag too long to be acceptable by the laws of physics.  Come to think of it, this same (or a similar) issue should affect replicator and holodeck technology as well.  Has any of this ever been addressed canonically, either in a Star Trek episode or in technical manuals?


I need to save statistics from past 7 days. But tomorrow I need to remove or replace data that was saving 8 days ago. I was thinking about having a table with 8 columns (name + 7 days) and every night remove last one and create new but it sound bad. What is the best way to do this?

I have to collect statisctics by days, weeks, months and years of user activity for a site. I am the DB design stage and I wanted to do this stage properly since it will make my coding life easier.  What I have to do is just simply increment the values in the fields by 1 in the DB each time an activity happens. So then I can pull up the date by each day, each week, each month and year. How should my DB be structured? Apologies if this is a simple question for most. It would also be great if this structure could be extendable so that it can be broken down by other categories.  The bit am having trouble with is each month is made up of more days and these days change each calender year.  Thanks all for any help or direction.  Other info: Linux Machine, making use of PHP and MySQL