I'm starting with a course of Introduction to Category Theory, and perhaps is dumb what I'm asking but I'm looking for an example of a monomorphism and epimorphism that is not isomorphism. Can you help me?  Thank you in advance!

It seems to be that if a map is both an epimorphism and a monomorphism, it is not necessarily the case that it is an isomorphism.  However, in the category of sets, if a map is both an epimorphism and a monomorphism it is an isomorphism.  Are these accurate statements?


I got the result from wolfram alpha: $\sum\limits_{i=k}^n {{i-1}\choose{k-1}} = \frac{(n+1-k){{n} \choose {k-1}}}{k}$, but I can't see how it derived it. The expression could be slightly simplified: $\sum\limits_{i=k-1}^{n-1} {{i}\choose{k-1}} = \sum\limits_{i=m}^{n-1} {{i}\choose{m}}\ ;\ m=k-1$. But I still can't see a solution.

Let $n$ be a nonnegative integer, and $k$ a positive integer. Could someone explain to me why the identity $$ \sum_{i=0}^n\binom{i+k-1}{k-1}=\binom{n+k}{k} $$ holds?


When I watched Rogue One, of the millions of questions I asked myself (most of which were admittedly a variation of "why?"), there was one that stuck with me from beginning to end.  What is up with Galen's house on Lah'mu?  It was identical to Uncle Owen's house on Tatooine, right down to the blue milk.    This bugged me because it seems weird that two completely different planets with completely different resources would favour identical architectural styles.  Star Wars usually does a great job of depicting very different cultures through set design alone, but here they essentially copy-pasted Uncle Owen's moisture farm house.    My question is this:  Is there an in-universe justification for why Galen's house on Lah'mu would look so similar to the buildings you'd expect to see on Tatooine?

At the very start of Rogue One, we see several objects that look like this:    This looks very similar to a moisture vaporator from A New Hope:    Moreover, we learn that these objects are used for farming. However, it seems unlikely that the ones in Rogue One are used for moisture farming, since: (the following spoiler is extremely minor)      it rains a short time after we first see them - and the presence of mosses and very green grassland suggest that this is not a rare event in this climate. It's also worth noting that we don't see any evidence of crops or livestock, just green ungrazed grassland and bare rock.   Given this, my question is, what are these objects and what are they used for on this world? What does this farm produce?


If you have a boolean variable:  boolean myBool = true;   I could get the inverse of this with an if/else clause:  if (myBool == true)  myBool = false; else  myBool = true;   Is there a more concise way to do this?

Is there a better way to negate a boolean in Java than a simple if-else?  if (theBoolean) {     theBoolean = false; } else {     theBoolean = true; }


It is often the case that the proposal of a specific idea or approach to a problem (or whole field of research)  triggers a sequel of papers discussing and extending this idea. In this sequel there are papers (probably two or three) that are established as "basic", as points of reference. Each one of them may be usefull in more than one directions of research. However  the  whole set of "basic" papers is characteristic of the discussion.  In this perspective the most efficient way to follow an approach or school of research is to search for articles that cite these (two or three) "basic" papers.  However, according to  question this option is not available, but one has to write some Python code.  That was a year ago.  Is there any new  user-friendly alternative?

For given papers A and B, I would like to search for all papers that cite both A and B. I guess one can generalize to papers {A,B,C,...} and find all papers that cite all of them.   A quick Google Scholar and Web of Science search revealed nothing. Google Scholar has a "cite=..." thing in the URL, which I messed with a bit to no avail.


I have downloaded the font for free on a website. How would I go about implementing it to use it? And, would it be supported with other browsers et etc.

Is there a way to add some custom font on a website without using images,  or some other graphics?  For example, I was working on a wedding website, and I found a lot of nice fonts for that subject. But I can't find the right way to add that font on the server. And how do I include that font with CSS into the HTML? Is this possible to do without graphics?


By default, I have to wait for a few seconds for the notifications to fade off.   I'd like to know the command to kill them immediately, so I can bind it to a shortcut key. (Super+N seems good right now.)  PS: I tried installing notify-osd, but the terminal says it couldn't find the package notifyosdconfig.

So I wrote a little script that makes sure a certain user plugs in a laptop when he logs on (it disables if he doesn't). The script uses notify-send to tell him to plug it in. If he plugs it in, the script quits. Is it possible to clear the notification automatically when he plugs it in? I'm thinking it might require somehow getting the process id spawned by notify-send and killing that PID, but I don't know how to do this.  Here's the current script:  #!/bin/bash   cat /sys/class/power_supply/BAT0/status OUTPUT="$(cat /sys/class/power_supply/BAT0/status)" echo "${OUTPUT}" if [ "${OUTPUT}" = "Charging" ] || [ "${OUTPUT}" = "Unknown" ]; then     echo charging or full elif [ "${OUTPUT}" = "Discharging" ]; then     notify-send -i /home/evamvid/Documents/Programming/OokiNoUse/power25.png "Hey there brother" "plug it in"     COUNTER=0 while [ "$COUNTER" -le 12 ] do     cat /sys/class/power_supply/BAT0/status     OUTPUT="$(cat /sys/class/power_supply/BAT0/status)"     echo "${OUTPUT}"     if [ "${OUTPUT}" = "Charging" ] || [ "${OUTPUT}" = "Unknown" ]; then         exit     elif [ "${OUTPUT}" = "Discharging" ]; then         COUNTER=$(($COUNTER+1))         echo $COUNTER         sleep 1     fi done fi


With the new administration, there is a potential for changes in the tax code.  The one that interests me the most is the possibility that the rate for long-term capital gains (now 20%, maximum) will be raised to the rate for ordinary income which might be as high as 39.6%. I seem to remember that changes in tax rates were not retroactive to before the change was proposed in the bill.  Was this usually the case, and is it likely to be the case in 2021, or is it a coin toss at this stage?

If the US Congress passes major changes to federal income tax laws, such as new income tax rates, what is the soonest that those changes would normally take effect? Would it be the same year, if passage were early enough in the year? How early in the year would it have to be? Or would it normally take effect the following year?


I have tried to replace a string in an array then conver it to string but it was not like I want. Here is my example:      String data = "ABC   00 0 03 54            BTT";     String[] tokens = data.split("\\s+");     for(int i=0; i<tokens.length; i++){         if(tokens[i] == "BTT"){            tokens[i] = tokens[i].replace("BTT"," ");         }     }     data = Arrays.toString(tokens);     Log.log(Log.VRB, "DEBUG: field =" + data);   OUTPUT: DEBUG: field =[ABC, 00, 0, 03, 54, BTT]  But I had tried to get this output: DEBUG: field = ABC  00 0 03 54  Can anyone give me the idea how can I fix it?  Thanks.

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?


Assuming $X_n$ has a discrete distribution on the set $\{\frac{1}{n}\frac{2}{n},...,\frac{n-1}{n},1\}$. We want to show that $X_n \xrightarrow{D}U(0,1)$. I tried to find the CDF of $X_n$ to start, but I unsure how to do this. If I find $\lim_{n\to\infty}F_{X_N}$ and then compute the partial derivative with respect to $t$ and show this is equivalent to $U(0,1)$ I think I will be done. But I don't know how to find the CDF. Any help with this would be greatly appreciated. Thanks

$\newcommand{\floor}[1]{\left\lfloor #1 \right\rfloor} $  Show that if $P(X_n = i/n)=1/n$ for every $i = 1,...,n$, then $X_n$ converges in distribution to a uniformly distributed random variable $X$.  Convergence in distribution is defined as   $$P(X_n \leq x) \rightarrow P(X \leq x)$$  and I have that a uniform distribution with parameters $a$ and $b$ implies that  $$P(X \leq x) = \frac{x-a}{b-a}$$  I cannot go any further however. I feel like I don't know anything about $X_n$ - I don't even know if it is continuous or discrete. What I can just say is that   $$P(X_n \leq x) = \sum_{i=1}^\floor{x} \frac{1}{n}$$  where $\floor{x}$  means rounding $x$ to the closest lower integer.


Somehow I've got text messages syncing to my email account.  I can't figure out how to stop a copy of all text messages going to my email.  I hope someone can help me with instructions.  Thanks!

I recently started using a Samsung Galaxy S4 and one of the features in a synchronization between text messages and email accounts.  When a text message comes in it throws a copy into my Exchange email accounts that are one the phone. I want to turn this feature off but cannot find a setting for it anywhere.  Any ideas?


I’m a new player to MTG and I was wondering what item I should use to keep track of the Power and Toughness in my creatures. Like if I would enchant one of my creatures with a +1/+1 I would need to be able to show it right? I thought I could use dice but I saw many people online discourage it because it can get knocked down easily and other problems. I don’t know if I should use dice or use something more convenient and better.

Card example:   There are a lot of cards that use counter as a noun. I did some Googling but I'm just not clear on what I need to use for counters.  Are they physical things I can buy and if so, what is a good online resource?  Can I just make do with coins or something?


When I have a function that changes an object, I expect the value of the object to change in the calling function (as described in  since the reference is not changed). But it doesn't seem to work for the wrapper classes (like Integer). The following code: public class Test {     private static class MyInt     {         private int i;         public MyInt(int i)         {             this.i = i;         }         public int get()         {             return i;         }         public void set(int i)         {             this.i = i;         }         public void increment()         {             ++this.i;         }         public String toString()         {             return Integer.toString(i);         }      }      public static void test(int a, Integer b, MyInt c)     {         ++a;         ++b;         System.out.println("b after increment is " + b);         c.increment();     }      public static void main(String[] args)     {         int a = 5;         Integer b = new Integer(5);         MyInt c = new MyInt(5);          test(a, b, c);          System.out.println(a);         System.out.println(b);         System.out.println(c);     } }  generates the following output: b after increment is 6 5 5 6  from which I can see that Integer object does actually change inside the function, becoming 6, but it doesn't change the value of b in main. What is happening here? Are wrapper objects passed in some other way than regular objects?

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


I am using Oracle 11G. I have a table called Tickets in the schema called 'tickets1" I have the same table structure in another schema called 'tickets2' I want to find out  What data is the same in both tables? What data is different?   CREATE TABLE tickets(     ticket_number NUMBER NOT NULL,         first_name VARCHAR2(50) NOT NULL,     last_name VARCHAR2(50) NOT NULL,     PRIMARY KEY(ticket_number) );

How to compare values between two different tables?  I have two tables as shown below:   Table 'A' sql_id       OPERATION       OPTIONS  63kf3an2j0pk SELECT STATEMENT 63kf3an2j0pkc TABLE ACCESS FULL  Table 'B' sql_id       OPERATION     OPTIONS 63kf3an2j0pk SELECT STATEMENT 63kf3an2j0pkc INDEX UNIQUE SCAN IDX_THU   I need to compare the values in Table 'A' and Table 'B' for the given sql_id. My question is how to find the changed values.  In this case in Table 'A' the second line is TABLE ACCESS FULL. Table 'B' the the second line is INDEX UNIQUE SCAN IDX_THU. So here the value has changed. How can I find that using query? Something like when matched then "matched" when not changed "value changed".  I'm looking for output something like below:     sql_id           comaparion outcome dmqb1hzrf5uxh   No change in the plan 74anujtt8zw4h   plan changed   Can I do something like this?  select sql_id,case when ( select sql_id,OPERATION,options  from  a where sql_id='dmqb1hzrf5uxh' minus  select sql_id,OPERATION,options from  b where sql_id='dmqb1hzrf5uxh') is null then 'matched'  else 'changed' end as status;   I am comparing the explain plans before and after patch. The table 'A' is before patch result of the sqlid and table 'B' is after patch result. Now I want to compare the plans in both the tables. I want to compare the plan by using a query.


public class LocalVariables {      static public void main(String args[]){          int var;          if(args.length > 0){             var = 10;          }          else{             var = 20;         }         System.out.println(var);     }  }   Here if I remove else part it's showing compilation error as:  Exception in thread "main" java.lang.Error: Unresolved compilation problem:  The local variable var may not have been initialized   Explain how the local variable value is initialized if I use else part.

Consider this:  public class TestClass {      private String a;     private String b;      public TestClass()     {     a = "initialized";     }      public void doSomething()     {     String c;          a.notify(); // This is fine     b.notify(); // This is fine - but will end in an exception     c.notify(); // "Local variable c may not have been initialised"     }  }   I don't get it. "b" is never initialized but will give the same run-time error as "c", which is a compile-time error. Why the difference between local variables and members?  Edit: making the members private was my initial intention, and the question still stands...


Self studying Lagrangian mechanics using Goldstein. Holonomic constraints, an example being the distance between two particles of a rigid body, can be expressed as  $(r_i - r_j)^2 - c_{ij}^2 =0$ and non-holonomic constraints can be expressed as $r^2-a^2 \ge 0$ Can you help me understand this? Where this comes from and what it means?

:     holonomic constraints are relations between the position variables (and possibly time) which can be expressed in the following form:   $$f(q_{1},q_{2},q_{3},\ldots ,q_{n},t)=0$$      where $\{q_{1},q_{2},q_{3},\ldots ,q_{n}\}$ are the $n$ coordinates which describe the system. For example, the motion of a particle constrained to lie on the surface of a sphere is subject to a holonomic constraint, but if the particle is able to fall off the sphere under the influence of gravity, the constraint becomes non-holonomic. [...] the second non-holonomic case may be given by:   $$r^{2}-a^{2}\geq 0.$$   Is this really a non-holonomic constraint? Consider the following function $f(r)=\min(r^2-a^2,0)$. Then we have  $$r^{2}-a^{2}\geq 0\quad\text{iff}\quad f(r)=0.$$  Doesn't this mean that the constraint is in fact holonomic?


my android phone got stolen a few hours ago. the thief has already removed both the internet sims.  as such, i had not installed AndroidLost or Mobile Tracker apps in the phone as it is a relatively new one.  i have tried to remotely install it, but it may take time .  please help out with the procedure and suggest methods to get it back.

I realize this is a long shot, but my phone was lost or stolen a few hours ago.  At the time it was stolen, I didn't have any specific applications installed to track it or wipe the data. So... my bad. I'm hoping the fact that I have a pattern lock will at least prevent anyone from accessing my data.  My question is, do I have any options for tracking or data wipe after the fact? (I'm more interested in tracking.)  Note: I have read similar questions, but unless I'm mistaken, they all address the question in terms of preparation before losing the phone. I'm asking about fallback options after losing the phone.


I am aware that you can right-click on an application and choose "Add to Favorites". I am trying to add it to the favorites section without using the GUI at all. Everything needs to be done in the terminal or a script.  Anyone have any ideas?  This is not a duplicate of . That is for SETTING the favorites, not ADDING to the favorites. When you right click on an application and choose "Add to Favorites", that must run a script somewhere that takes an input of the application name. What I'm asking is, where is that script or how can I replicate it?

I have a custom .desktop file: [Desktop Entry] Type=Application Terminal=false Icon[en_US]=/home/alex/bin/idea-IC-173.4127.27/bin/idea.png Name[en_US]=IntelliJ Exec=/home/alex/bin/idea-IC-173.4127.27/bin/idea.sh Name=IntelliJ Icon=/home/alex/bin/idea-IC-173.4127.27/bin/idea.png  Output of ls -lha .local/share/applications/intellij.desktop: -rwx--x--x 1 alex alex 248 Dez 30 10:54 .local/share/applications/intellij.desktop  Answers posted to a previous question () don't work for me. I can find this launcher in Activities and I can double click on that file and IntelliJ will start. Nevertheless, I cannot add this launcher as a favorite to the dock. The option does not show up.


I would like to suggest a new feature that when reviewing suggested edits on sites that support MathJax that the suggested edit queue renders the MathJax in the rendered output view. The following suggested edit on Electrical Engineering is an example:    Personally I find that verifying the edit is valid is difficult when that view doesn't render the MathJax. I've been in the habit of opening a new window to paste the markup into a new question (that I discard) to view the rendered output, but it doesn't make for a very efficient workflow.

In a suggested edit I just reviewed, about a third of the MathJax renders properly, but the rest doesn't. Note that the delimiters on puzzling are \$, so that doesn't escape it.    Related:  Don't render MathJax when viewing source:   Render MathJax when viewing rendered output:


I found some webpages but not helpful to me. I'm using MikTex 2.9 with pdfTeX. Thanks.

What's the best strategy for spell checking LaTeX documents?


Thanks for the suggested solution. I have tried it and after some fiddling it works, however I am stuck on how to edit the generic 'List of Figures' heading to match my modified 'List of Plates' heading. This is how I changed the command you provided.   \usepackage{float} \newfloat{plate}{htpb}{plt}[chapter] \floatname{plate}{Plate} \renewcommand{\theplate}{\arabic{plate}} \setcounter{plate}{1} \newcommand{\listofplatesname}{\large List of Plates} \newcommand{\listofplates}{%   \addcontentsline{toc}{chapter}{\listofplatesname} \listof{plate}{\listofplatesname}}       In my document (book class) I have two files in the backmatter containing illustrations. Using \listoffigures generates a combined list of figures. I would like to generate a separate list of illustrations for each file starting on its own page and with its own heading to put in the Table of Contents. Wondering if there is a simple solution for this?  \addcontentsline{toc}{chapter}{\normalsize \textbf{Plates} Colour Folios} \input{chapterPLATES}  \addcontentsline{toc}{chapter}{\normalsize \textbf{Figures} Comparative Illustrations} \input{chapterFIGURES}  \addcontentsline{toc}{chapter}{\normalsize References for Illustrations} \renewcommand{\listfigurename}{ \large Figures} {\small\listoffigures}

I'm trying to get two separate lists of figures. Ones are the figures containing some plots created using tikzpicture like:  \begin{figure}   \begin{tikzpicture}     \begin{axis}     ...     \end{axis}   \end{tikzpicture} \end{figure}   and the others are simple images. At result I need to have List of Figures and a List of Plots. How can I achieve it? Please give an example if possible.


How can I style html the input file type using css, and also change the browse button, thanks

How do you style an input type="file" button?


I know that $x-1 < \lfloor x \rfloor \leq x$ hence  $1-\dfrac{1}{x}<\dfrac{\lfloor x \rfloor}{x} \leq 1$ for $x>0$. I think it is easy to see from this that the limit should be 1 but I don't know how to formally prove this.

Find the limit  $$\lim_{x\to \infty } \ \frac {[x]}{x}.$$  Does $[x]$ means greatest integer in this case?


Consider a financial system, where the customer demands a financial statement consisting of | opening_balance | amount_credited | amount_debited | closing_balance | remarks. Two approaches to doing this are:  Store the above details (opening_balance, amount (+/-), closing_balance) during transaction entry  Just record the amount(+/-) & remarks and get my final statement from performing window queries in SQL (specifically LEAD() and LAG() functions)   Challenge: Consider 5 entries 1, 2, 3, 4, 5. There are high chances that middle entries will change at any time. For example, if the transaction_amount of 2nd entry changes, then it will affect the closing_balance, in return it will affect the opening balance & closing_balance of 3rd entry, and so on, sort of a chain. Which approach better suits the current scenario? PS. I'm using Django, but I don't really care about this, because my concern is the concept of implementation

I have been struggling trying to find a way to properly and reliably maintain a balance for accounts in an order/payment system.  Currently, the process consists of three tables. Below example is very simplified but gets the point across.  Table one contains the account ID, name, total paid, total orders, balance etc.  Table two contains payments, date, the account ID (FK) and amount.  Table three contains orders, date, the account ID (FK) and amount.  Calculating the balance is of course as easy as  SELECT SUM(payments.AMOUNT) FROM payments WHERE ID = [account] SELECT SUM(orders.AMOUNT) FROM orders WHERE ID = [account]   Followed by some simple addition/subtraction math:  UPDATE accounts SET BALANCE = [balance] WHERE ID = [account]   All good - the problem is - how do I maintain this over let's assume years of activity and many, many transactions?  Currently the accounts table is updated every single time a transaction is made, meaning the above three statements run every time. There is of course an index on the ID column in all three tables, and everything is fast and neat for now, but I work with less than 100,000 transactions, meaning everything fits into the RAM and basically all I throw at the database gets executed immediately. Over time this will change, of course - so how do I handle this?  Is it better to mark the accounts as "dirty" and process balancing in a batch job later, or can I keep updating the balance real-time even when I reach the point where the orders and payments tables will not fit into the RAM?  Do I need to segment the orders and payments and "lock" everything before a given time, such as before last calculation? (I would rather not). I ask because then I could do a SUM WHERE DATE > [last lock timestamp] and update with UPDATE BALANCE = [balance] + [value for last lock] and prevent the problem from outgrowing resources.  I don't need a running balance for each transaction. That's all I can find results for when I try to research this problem. I just care about the total amount paid, the total amount ordered and the balance of accounts.  Why don't I calculate on the fly when I need the balance, you ask? Because one must be able to query the system and ask "Which of my (let's say) 50.000 accounts have a balance below 0?" - something we cannot do easily if we do not store the balance with every account.


I have combined different layers (vector) in a merged layer. All layers had one specific land-use type, so now the new layer has fields called 'tree', 'paved', 'building', 'water' and 'plants'. All these fields either have value 1 or 0. (1 for when this feature has the specific land use and 0 if it doesn't). This means that all features only have one '1' (either in tree, paved, building, water or plants). The other of those fields will then just have 0.   Now I want to add those fields to a new field, so that this field has the type of land cover for each feature, (combine type of land cover into one field basically).  How do I do this?

I have a vector shapefile with a column with string values. How can I convert this to a column of integer values in another column but keep the categorization.  e.g. from:  col1,newcol2 A, A, B, A, C,    to:  col1,newcol2 A,1 A,1 B,2 A,1 C,3    I'm sure it is in the 'replace' or 'case when' syntax somewhere but I cannot find a clear method via Google etc.


Everytime I try to update my ubuntu, it returns this:         W: Failed to search   404  Not Found      W: Failed to search http://ppa.launchpad.net/chromium-daily/ppa/ubuntu/dists/trusty/main/binary-i386/Packages  404  Not Found      W: Failed to search http://ppa.launchpad.net/gwibber-daily/ppa/ubuntu/dists/trusty/main/binary-amd64/Packages  404  Not Found      W: Failed to search http://ppa.launchpad.net/gwibber-daily/ppa/ubuntu/dists/trusty/main/binary-i386/Packages  404  Not Found      E: Failed to download of some indexs. They were ignored or others have been used in the place   And also I can't install pygame...

PPA seems to be constantly offline. Whenever I use sudo apt-get update, this error is shown:  W: Failed to fetch http://ppa.launchpad.net/ 404  Not Found   How do I fix these errors?


The masters, many of them young men who agreed that Chips was hopelessly old-fashioned, rallied round him  Why is it round him and not around him? What's the difference?

When I am writing I often come across the words "around" and "round." I was wondering what is different between them, and how they would be used in different contexts.


I have floated images and inset boxes at the top of a container using float:right (or left) many times. Recently I hit a need to float a div at the bottom right corner of another div with the normal text wrap that you get with float (text wrapped above and to the left only).  I thought this must be relatively easy even though float has no bottom value but I haven't been able to do it using a number of techniques and searching the web hasn't come up with anything other than using absolute positioning but this doesn't give the correct word wrap behaviour.  I had thought this would be a very common design but apparently it isn't. If nobody has a suggestion I'll have to break my text up into separate boxes and align the div manually but that is rather precarious and I'd hate to have to do it on every page that needs it.  EDIT: Just a note for anyone who comes here. The question linked above as a duplicate is in fact not a duplicate. The requirement that text wrap around the inset element makes it completely different. In fact, the response to the top voted answer here makes it clear why the answer in the linked question is wrong as a response to this question. Anyway, there still doesn't appear to be a general solution to this problem but some of the solutions posted here and in the linked question may work for specific cases.

Given the following HTML:

     Copyright Foo web designs

    I would like #copyright to stick to the bottom of #container. Can I achieve this without using absolute positioning?


I think the formula is $n^2$.  Define $p(n): 1 + 3 + 5 + \ldots +(2n − 1) = n^2$  Then $p(n + 1): 1 + 3 + 5 + \ldots +(2n − 1) + 2n = (n + 1)^2$  So  $p(n + 1): n^2 + 2n = (n + 1)^2$  The equality above is incorrect, so either my formula is wrong or my proof of the implication is wrong or both.  Can you elaborate?  Thanks.

The question asks to verify that each equation is true for every positive integer n.   The question is as follows:  $$1+ 3 + 5 + \cdots + (2n - 1) = n^2$$  I have solved the base step which is where $n = 1$.  However now once I proceed to the inductive step, I get a little lost on where to go next:  Assuming that k is true (k = n), solve for k+1:  (2k - 1) + (2(k+1) - 1) (2k - 1) + (2k+2 - 1) (2k - 1) + (2k + 1)   This is where I am stuck. Do I factor these further to obtain a polynomial of some sort? Or am I missing something?


When I was checking someone's profile, I came to know that I can see his reputation history too with the time of that activity. Now, suppose if I get a downvote and I suspect someone for this, so if I check his reputation history, I must see a -1 on his reputation at the same time when I got the downvote.   Does this make downvoting non-anonymous?

I've noticed that if I downvote an answer, the record of the downvote is visible to me in my profile.  But when I view my profile from another browser that's not logged into Stack Overflow, I've noticed that I don't see the record of the downvote.  So I was wondering if the downvote record is visible only to me?  If so, is this done to protect downvoters from retaliation?


On Debian, if the package you're installing has systemd services, they will be automatically enabled and started at post-install. I have found , but not the former (yet).  It seems like the post-install scripts use deb-systemd-helper to do this, which means disabling it shouldn't be impossible.    Edit: This is what I ended up doing.  /etc/systemd/system-preset/00-disable-all.preset:  disable *

I've created a  package which installs a service.  On our embedded devices, I want this package to automatically enable the service.  On our developer workstations, I want the developers to systemctl start foo manually (it's a heavy service, and so it just consumes resources if run all of the time on a desktop environment).  How can I go about prompting the user for their decision during the apt-get step? Is that the best solution?  Note, I've created the package using dh_make and debhelper and enabled it with:  %:     dh $@ --with=systemd  override_dh_systemd_enable:     dh_systemd_enable --name=foo foo.service


I'm listing below the specs of my Lenovo laptop:   Lenovo ThinkPad T430  2349-Core i5 2.6 GHz-3230M/64-bit  Windows 10 Pro/Windows 7 Professional 64-bit  4 Gb RAM 500 Gb HDD DVD printer 1366 x 768/14 wide  HD-Intel HD Graphics update 4000   I'm hoping to run the latest Ubuntu on my Laptop, but it's not on  list, and so I'm a little worried that if I switch from Windows10 to Ubuntu the hardware might not be 100% compatible resulting in poor performance.  As a side note, I did see the T440 and T450 in the list but for past releases, and Lenovo in general seems to be pretty compatible with Linux. Do you guys think that it's okay to make the switch? Thanks!!

I have a device on which I would like to install Ubuntu. How do I find out if Ubuntu will work on it?


Background A  spell is cast as a reaction to an attack that hits.  It applies its AC bonus even against the attack to which it is a reaction, meaning that it can make the attack that hit, retroactively miss and thereby not do damage. Shield 'interrupts'/potentially cancels its trigger, as stated in the DMG in the . Since the hit has retroactively become a miss, what happens to effects that were triggered by the hit in the first place?  Are they undone as well, or do they persist?  has two answers of nearly equal popularity, with one arguing that other effects triggered by the hit still persist, and the other arguing that they do not.  On the side of the argument that they do not occur is a (now-unofficial) tweet from Jeremy Crawford stating  If the attack has a special effect that relies on it hitting, that effect doesn't occur if the attack is turned into a miss.  However, the discussion on both sides therein focusses on a narrow interpretation of 'effects' as discrete, measurable things that happen to specified targets - the hit on the caster of the Armor, and the resulting damage to the creature making the attack. Are the 'special effects' of an attack referred to limited to things like damage or conditions that affect just the target of the attack, or do they include intangibles like knowledge for all intelligent observers? Scenario A party is traversing wilderness with abundant natural cover as well as opponents who are seeking to ambush them. A hidden opponent fires a missile weapon at a party spellcaster and hits.  In response, the spellcaster uses the shield spell and turns the attack into a miss.  However, the ambusher has now revealed their location to the spellcaster and everyone else in the party, since according to the rules of   If you are hidden--both unseen and unheard--when you make an attack, you give away your location when the attack hits or misses.  The party members begin to defend themselves and target the ambusher. The next round, a second hidden ambusher also fires at the spellcaster, hits, and also reveals their presence to the caster and the rest of the party.  The spellcaster again uses shield, and again converts the hit into a miss. This second ambusher, however, possesses the Skulker Feat (PHB 170)  When you are hidden from a creature and miss it with a ranged weapon attack, making the attack doesn't reveal your position.  Since the attack was now actually a miss, does the knowledge of ambusher's location persist as revealed, or is this knowledge undone? Does... ...the shield spell travel back in time, converting the hit to a miss before the party had knowledge of the second ambusher's location? ...knowledge of the ambusher's location count as a 'special effect' of the attack hitting, that now does not occur since the attack resolved as a miss? ...the 'special effect' of the knowledge of the ambusher's location get removed from only the caster, while their companions still know where the ambusher is? ...the knowledge of the ambusher's location not count as a 'special effect' of the attack, but rather as mundane effect, that is not changed by the shield spell? A good answer may use the Crawford quote or not.  If it does, it should convincingly interpret what is a 'special effect' and to whom it applies.  If the answer does not use the Crawford tweet, it should explain from where it draws its reasoning.

I am contemplating a Oath of Conquest Paladin / Sorcerer multiclass character, with a 1 level dip in hexblade warlock. This character will have access to the Armor of Agathys and Shield spells, which potentially allows for a pretty nice combo. The Shield spell states (PHB 275):  Casting Time: 1 reaction, which you take when you are hit by an attack or targeted by the magic missile spell... Until the start of your next turn, you have a +5 bonus to AC, including against the triggering attack,  It looks like you are indeed hit by an attack, but since you have a bonus to AC, you can potentially force that attack to miss instead. Armor of Agathys states (PHB 215),  If a creature hits you with a melee attack while you have these hit points, the creature takes 5 cold damage.  If I cast Shield and cause an attack that "hit" me to miss, does Armor of Agathys still deal damage? I am leaning toward yes, though this combo seems a little too strong--Shield is already a strong spell, and this character will eventually have 9 1st level spell slots and a 7th level spell slot. Not only can they freely block attacks with Shield, but they can also deal up to 35 (5d10) damage to the attacker without an attack roll or saving throw. While a Warlock would have to spend both of their spell slots to do this once, my character would be able to do this 4 times with spell slots to spare. Some notes:    ask about reducing the damage from a confirmed hit to zero. This question is asking about what happens when the Shield spell causes the attack to miss entirely. A number of online resources, such as the Roll20 5th edition compendium, seem to be missing the correct casting time for the Shield spell. Answerers should make sure they're looking at the correct version from the PHB.


Whether you have the app installed or not, trying to install a new version fails. It reaches 100% but then an alert pops up stating that the app could not be installed at this time.  The profile appears to be valid, so I'm not sure why it fails... Too bad I was tempted to check if this also happens if you remove the app... meh.

When installing the latest version of the iOS app it fails telling it can't download the update. It happens at approximately 75% in the loading phase.  I have tried it on various networks and have done a lot of attempts already.  Is this a deployment bug?  Update:  It seems to be a deployment bug indeed since the update is retracted now and can't be downloaded any more. The app doesn't show an update too.     App Version: 1.3.2.231 Device: iPhone7,2 OS Version: Version 9.0 (Build 13A344)


Why do we call y = mx + b linear (in high school)? Why don't we call it affine?  and linear what is actually linear  $$f(x+y)=f(x)+f(y)$$ $$f(ax)=af(x)$$

Consider $f(x) = mx+b$. Let $b\ne 0$   If $f$ is linear, $f(0)$ should yield $0$ $f(0) = m(0)+b = b$ Therefore $f(x)=mx+b$ is nonlinear.    Question:  Why is $y=mx+b$ called a ""?     Remark:  Consider $f(x,y) = y + -mx = b$  \begin{align} \alpha f(x,y) &= \alpha b \\ f(\alpha x,\alpha y) &= \alpha y +-\alpha mx = \alpha (y +-mx) =\alpha b \end{align}  \begin{align} f(x+\beta,y+\beta) &= y + \beta+ - m (x +\beta) \\&= (y+-mx)+(\beta +-m\beta)\\ &= f(x,y)+ f(\beta,\beta)  \end{align}  Therefore, $f(x,y) = y +-mx$ and $f(x,y) =b$ are linear.   Question:  Why is this not a contradiction?


I'm trying to understand how SQL injections fully work in order to feed this information back to some of my students. I have created a simple webpage with a small SQL database attached and would like my students to attempt to "break into" the site and get the token on the welcome page.   However, the resource I used (w3schools) to create the login page only showed me a secure webpage, and I'm not sure how to unravel it to make the login page susceptible to an SQL injection.  So far, the code I have for the webpage is below (stripped to only the essential part of the HTML!)   <?php    include("conf.php");    session_start();        if($_SERVER["REQUEST_METHOD"] == "POST") {             $myusername = mysqli_real_escape_string($db,$_POST['username']);  //get username and password from form       $mypassword = mysqli_real_escape_string($db,$_POST['password']);               $sql = "SELECT * FROM admin WHERE username = '$myusername' and password = '$mypassword'";  //sql query - IF username AND password match what is in the database        $result = mysqli_query($db,$sql);       $row = mysqli_fetch_array($result,MYSQLI_ASSOC);       $active = $row['active'];              $count = mysqli_num_rows($result); //return the number of results - there should only be one!               if($count == 1) {  //if there was 1 result, load the welcome page          $_SESSION['username'] = $myusername;                    header("location: welcome.php");       }else {  //otherwise show an error          $error = "Your Login Name or Password is invalid";       }    } ?>                                   <form action = "" method = "post">                   UserName  :<input type = "text" name = "username" class = "box"/>

                   Password  :<input type = "password" name = "password" class = "box" />

                   <input type = "submit" value = " Submit "/>
                </form>                              I've attempted to change the line:   $myusername = mysqli_real_escape_string($db,$_POST['username']);  to  $myusername = $_POST['username'];  as I assumed that it was being escaped (mysqli_real_escape_string) and preventing any extra characters from being entered into the text box - is that correct?  But that didn't do anything. Any help would be appreciated.

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


In Westworld, what's the underlying power source for the hosts?  Do they digest food like humans to generate calories?  I think this is especially important to know in S2.

We learn from Ed Harris that initially, the hosts were androids - mechanical robots made to look like humans. This is also seen in some flashback sequences, and Robert, the kid who opens his face to reveal the circuitry inside. In episode 6, we learn that the hosts were later switched to the current 3D-printing process, in order to appear even more human.  However, what exactly is their physiology? Their energy source? Do they need food or store it inside a stomach chamber? Or are they charged overnight, since obviously they do need a source of electrical power for remote control and data transmission?


I posted  some minutes ago, and I can reload that page to make sure it's there, but I cannot see it appear under the newest questions tagged "ruby". It is already several minutes ago. Why doesn't it appear?  Update After about ten minutes, I can finally see it appear. Why is this the case? Is there some delaying mechanism?

Recently, I read this  about how they have some of their infrastructure laid out. I was curious to know, does Stack Exchange use caching (both at the application layer and/or database layer) and if so, how?


I have the strangest php behavior I've never noticed before:  $array =array(0,1,2, 'parent');    foreach ($array as $value) {     if ($value=='parent')     {         echo $value;         echo '<br>';         continue;      }  } exit;   Will return  0 parent   I was wondering if anyone could explain to me why it matches the 0 to the string 'parent'?

What is the difference between == and ===?  How exactly does the loosely == comparison work? How exactly does the strict === comparison work?  What would be some useful examples?


Concerning the base-collector barrier, the electrons coming from the emitter move through the barrier using diffusion mainly and drift. Does carrier injection happen as a result of these two mechanisms which leads it to be collected by the collector? I have some confusion here.

So, I understand that for a NPN transistor to work the emitter-base junction needs to be forward biased and the collector-base junction needs to be reverse biased.  I understand how current flows from the emitter to the base when forward biased, but I can't seem to wrap my head around how it flows from the emitter, through the base, and into the collector.  From what I understand about the depletion region of a PN junction diode, when forward biased, the electrons in the N-type material are repulsed by the negative charge of the supply (say a battery) and the holes in the P-type material are repulsed by the positive charge from the supply, thus narrowing the depletion region and allowing electrons to flow from the N region to the P region.  I also understand that the holes and electrons are attracted to the source charges when reverse biased, widening the depletion region and blocking any electrons from flowing.  What I don't understand is what happens to the depletion region of the collector-base junction that allows electrons to flow from the emitter to the collector even though the collector-base junction is reverse biased.  Take a simple common emitter circuit for example.  I apparently am not cool enough to post pictures yet so you'll have to use your imagination.  So pretend we have the base connected to the positive terminal on a 1v battery (Vbb).  The collector is connected to the positive terminal on a 10v battery (Vcc).  The emitter and both negative terminals are connected to ground.  Also pretend that there is some kind of current limiting.  How does current get from the emitter through to the collector?  I can see how they are at different potentials, but I don't understand how this overcomes the reverse biasing of the collector-base junction.  Can anyone tell me what actually happens at the junction to allow current flow and how changing Vbb will affect that current?


OK, I have to begin saying that I'm working with Visual Basic. The problem is that I have a Entity Framework object and I want to indicate that this object implements a interface, for example:  Public Interface ICatalog    Property created_at() As Date    Property id() As Long End Interface   Those properties are allready in the object. In c# I've done this just by declaring a partial class of the object and indicates that implements that interface, but in basic is not working, I supouse that is because of the language sintaxis used to declare that a property is implementing some property of the interface, for example:  Public Property created_at() As Date Implements ICatalog.created_at   So is there any other way to accomplish this?

Okay, I have ran in to a problem with VB.NET. So all those defenders of VB.NET please can you help me out? Here is my issue: I am using LINQ to Entities, it also works with LINQ to SQL, I build my edmx file I then create a Partial Publc Class of the same name as one of the entities All fine up to now, so here comes the problem.   I need the Partial class to implement an Interface Implements Interfaces.IAsset But VB.NET want to place "Implements Interfaces.IAsset.ID" at the end of the property, which of course is in the generated code section of the Partial class, which I can not do as the edmx file is auto generated and will change in the future.   Here is the line of code that needs sorting:   Public Property ID1() As Integer Implements Interfaces.IAsset.ID   In C# it is fine and works wonders. So why can't VB.NET implement an interface that is in the code generated class?


I found a  currently living on earth. Now I'm wondering If anybody tried to estimate the number of species that have lived on earth. I'm familiar with problems of "species concepts". But I'm sure, there is at least a number of all known fossils.  EDIT: In contrast to the question  I'm asking for species and not for individuals. The answer to my question can be used to ansewer the queston for the number of organisms. But still, The questions is different.

I've looked for some information on this, but couldn't find anything useful. Has there been any noteworthy attempt to estimate the sum amount of individuals of all species that have ever lived on Earth?


I'm working on CSES number spiral problem and I've noticed that c++ isn't calculating it right? ans = pow(y, 2) - (x-1);  This is the code and I have x and y both set as 1000000000. cout << "pow =" << pow(y, 2) << "\n"; cout << "x-1 =" << (x - 1) << "\n";  I've put this right before the calculation and pow shows up correct with 1e18 and x-1 is also correct with 999999999. cout << 1000000000000000000 - 999999999 << "\n";  If I manually write it like this it works but pow(y,2) - (x-1) doesn't. It will give me an answer of 999999999000000000.

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


i am new to linux and so far i am getting the hang of it but i was not able install anything with software center so i looked up the error i was getting and i found  and i did the first command "sudo apt-get update" and as always it asks for my password and i put it in and i get   Hit:1 http://dl.google.com/linux/chrome/deb stable InRelease Hit:2 http://archive.ubuntu.com/ubuntu xenial InRelease          Get:3 https://dl.winehq.org/wine-builds/ubuntu xenial InRelease [6,259 B] Get:4 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [109 kB]        Ign:3 https://dl.winehq.org/wine-builds/ubuntu xenial InRelease Get:5 http://archive.ubuntu.com/ubuntu xenial-security InRelease [109 kB] Fetched 225 kB in 2s (111 kB/s)                              Reading package lists... Done W: GPG error: https://dl.winehq.org/wine-builds/ubuntu xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 76F1A20FF987672F W: The repository 'https://dl.winehq.org/wine-builds/ubuntu xenial InRelease' is not signed. N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use. N: See apt-secure(8) manpage for repository creation and user configuration details.   and since i am new to linux i didnt know what it was doing i guessed it was getting the download files to install it with and so i put the next command "sudo apt-get install synaptic" and i got   E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable) E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?   and i didnt know what it meant so i tried to find the app and it doesnt show it, as if i never installed it. so i guessed it didnt work, so i tried the same command and got the same message. and i am on Ubuntu 16.04.6 LTS

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?


I am Linux user and currently there is no Windows* PC s available to me . I just want to experience the Windows 8 I have a Windows 8 Image/files I have a running Ubuntu PC I have an 8 GB USB disk I want to install Windows in a old PC which doesn't have support for UEFI boot. Is there any solution available ?

I'd like to create a Windows bootable USB stick, but I don't have a Windows machine with me at the moment to do so. How could I achieve the same using Ubuntu?


I just installed ubuntu 18.10 alngside windows 10. After the instalation completed and restarted this appeared on my screen. I am lvl 1 ubuntu user XD Thought someone here can help. Thanks!

I get this error message   NMI watchdog: BUG: soft lockup - CPU#2 stuck for 23s! [plymouthd:305]    on the startup of my system (even with live-cd).  My PC is a dell inspiron 7559 with intel graphic and nvidia.  UPDATE - this issue also happens when attempting to install ubuntu 18.10 using LiveUSB


I was reading the book "Essential Grammar in use" Third Edition by Raymond Murphy.   In page no.56, there were some questions about using Past Tense and Present Perfect Tense. In that, one question confused me a little. I've given it below,     The washing machine was broken, but it's OK now. It __________ (repair).   My answer at first sight was "was repaired" (wrong answer) because I thought the action was completed in the past.  But the correct answer given in the book was "has been repaired". It confused me a little. However, I understood it later that the action's result "It's OK now" has been related to the present. So the answer "has been repaired" seemed correct to me.  However I always confuse this below examples,     "I sent an email to you yesterday."      "We despatched a parcel to you yesterday."   vs.      "I have sent an email to you."      "We have despatched a parcel to you."   The first one should be the most common or correct answer. But what's wrong with the second one? Can I use it? Because the mail sent / parcel despatched has some connection with the Present, because it hasn't reached them yet.  Also please clarify, whenever I use Past tense, Is it always required to tell the time of action? Eg. "I sent an email to you yesterday."  I have already asked similar questions here. But still, I have some little confusions. As a non-native English speaker, most of the time, I think that something I did in the past has some connection with the present moment and I feel like I need to use " Present Perfect".  Please help me. Thanks in advance.  Update:  This question has been marked as duplicate. The other question was also asked by me. However this one is different & more in detail than the other question. That question was about the time markers (yesterday) with Present Perfect tense. But this is about no time markers, but I'm asking that, is it OK to use Present Perfect tense when the action was happened some hours ago however the action is still connected to the present moment.

I have a doubt in the below sentence whether to use Past Simple or Present Perfect Tense,     We have despatched the parcel yesterday.      We despatched the parcel yesterday.   I know the second one is right because the parcel was despatched yesterday which means the action is completed (Past Tense).  But what about the first sentence, because the parcel was despatched, however the parcel is not reached the customer yet. So is it ok to use "have despatched" in the sentence (Present Perfect) in the mail to inform the customer?


I am trying to solve the same problem on this . One gave an hint defining an inclusion function. Does someone know what is meant there?  Thanks

Prove that, there exists no continuous function $f:\mathbb R\rightarrow\mathbb R$ with $f=\chi_{[0,1]}$ almost everywhere.$\textbf(Make\ sure\ that\ your\ proof\ is\ completely\ rigorous)$.   I don't know, which property to use. (It is not allowed to show it with $\epsilon-\delta-criterion$, our last topics were: Lp-Spaces, Radon-Nikodym Theorem, Riesz Representation Theorem,Lipschitz-Functions, Product measures, Fubini Theorem)  but i can't find anything to do with continuity, which of them could be useful ?


I would like to know how I can find  the path of the recycle bin and its files.  I have tried  to find  them from a DOS command.  However, it took me to the recycle.bin but did not show its path.  How can I find out the path of recycle bin? Is there a command to retreive that?

I dragged a file to the recycle bin a few days ago. I have Windows 7 premium on a 245 GB partition, a 240 GB SSD, and a 250 SSD. And somewhere in the past few days I incidentally installed Delta Search. I know I should remove it right away, but I just switched to Windows on the partition of a 3.5 1 TB drive and would like to restore that file and deal with the malware after Christmas is over.  I'm pretty sure I know what drive that deleted files should be on, but what is the real name of the recycle directory and exactly where is it located? In other words, if I know the name of the drive what would the rest of the path look like so I can just paste it in my Explorer window and change the drive letter.


I was wondering if it's possible to change the splash screen of the newest Blender version (2.68a). You could change the splash in previous versions via splash.png but I can't find it in 2.68a?

The default Splash screens are cool, but I'd like to add some of my own work to remind me of how awesome I am (no, not really).    Is it possible to customize/change the splash screen?


I am writing a script to modify settings on my Ubuntu server.  I have the following line in it:  sudo sed 's/PasswordAuthentication yes/PasswordAuthentication no/' /etc/ssh/sshd_config   The problem is that the change will not remain.  It simply changes the 'no' back to 'yes'.  When the command executes, the modified file immediately displays in the terminal showing the 'no', but when I cat the file or open it in vim it shows a 'yes' again.  Additionaly, I can open sshd_config in vim and modify it manually and the change remains just fine.  Any thoughts?  Thanks.

Replacing strings in files based on certain search criteria is a very common task. How can I    replace string foo with bar in all files in the current directory? do the same recursively for sub directories? replace only if the file name matches another string? replace only if the string is found in a certain context? replace if the string is on a certain line number? replace multiple strings with the same replacement replace multiple strings with different replacements


[Edit]  Make it simple.  I invoked java xxx... on Machine A using putty to connect from Machine B. However I cannot reach Machine B. How can I connect Machine A from Machine C to set the running process java xxx... could not be terminated when Machine B shuts down?  [Original]  I'm connecting to a server(Machine A) using putty, and I'm running a process on it. However I have to reboot my computer(Machine B), which could terminate the connection as well as putty. Because I didn't set nohup on the process which I'm running, this could be terminated. I cannot use putty to set disown for some reasons. So I want to use Machine C to open putty to connect to the server(Machine A) and set the process I'm running that it won't be terminated when I reboot Machine B.  Is there any way to do this? I know I can use disown if I'm using the same shell process. But now is not this case.

I have a running program on a SSH shell. I want to pause it and be able to unpause its execution when I come back.  One way I thought of doing that was to transfer its ownership to a screen shell, thus keeping it running in there.  Is there a different way to proceed?


I am trying to link a digital pin to a pad that's already wired to an ADC. I was wondering how many ohm the ADC port internal resistance is.

I'm using the  on some small robotic arm motors, and reading in the analog voltage with an Arduino Uno.  I've had reasonably good results, but only after putting in an RC filter on the output.  However, in the application note on the datasheet, it says not to do that:  "the addition of an RC filter to the output of a sensor IC can result in undesirable device output attenuation — even for DC signals."  Then it gives a formula to calculate attenuation, but it depends on knowing the input impedance of whatever is reading the signal, so that's what I'm after here.


I have a sentence where I'm unsure about my grammar when discussing planets:   "Branch Technology is revolutionizing the use of 3-D printing to create architectural elements and structures that will enable new home designs not only for Earth but maybe even for the Moon and Mars."   Is this grammar and capitalization correct usage? I always get stuck on "the earth" or just "Earth."

In what cases do we have to put the definite article the before each of these words:   Sun Moon Earth   and in what cases do we not need to?


I am  an Ubuntu newbie user. I used Ubuntu on a virtual machine and I liked it very much. Now I want to install it instead of Windows 7 on ''C'' drive. Will that format my other drives too?

I current have Ubuntu Installed using Wubi under C:/ drive. Im on Ubuntu 11.10. Im planning a full reinstall of Ubuntu 12.04, but this time without Wubi.  I want to install Ubuntu on a Single Drive, like D:/ or G:/  Can I do that ? If I delete and make some unallocated space can I use that to Install Ubuntu ?  More Info :  Five Partitions  C: 135  D: 50  E: 50  F: 180  G: 50  Gparted shows I have Primary ntfs 135 and other 330 as extended.  I have Windows 7 x64


If there would be such a thing as a complex prime number, how would it be defined?  A normal prime is defined as a number only dividable by one or itself.. would that be "1+1i" with complex numbers?    Thanks in advance :)

I was just learning about how, if you multiply any two complex numbers together, you get a new complex number. With that in mind, is there such a thing as complex numbers that cannot be factored, or prime complex numbers.


In Mac OS X, run 'ls -al' gives me something like this.   drwxrwxrwx+  4 smcho  staff     136 May  5 09:18 Public drwxr-xr-x+  6 smcho  staff     204 Feb  1  2010 Sites drwxrwxrwx   9 smcho  staff     306 Feb  2  2010 backup drwxr-xr-x@ 36 smcho  staff    1224 Sep  4 22:51 bin    What's the + or @ at the end of the first column means? Is this unique to Mac, or common in UNIX?   ADDED  After Michael Mrozek's answer, I ran 'ls -ale' to get the following.   drwx------+ 66 smcho  staff    2244 Aug 30 13:40 Library  0: group:com.apple.sharepoint.group.3 allow search  1: group:everyone deny delete drwxr-xr-x   3 smcho  staff     102 Sep  4 15:01 Mail drwx------+ 13 smcho  staff     442 Aug 28 17:55 Movies  0: group:everyone deny delete drwx------+  6 smcho  staff     204 Jul  9 09:37 Music  0: group:everyone deny delete drwx------+ 11 smcho  staff     374 Aug 28 16:55 Pictures  0: group:everyone deny delete drwxr-xr-x   3 smcho  staff     102 Mar 18 15:43 Projects drwxrwxrwx+  4 smcho  staff     136 May  5 09:18 Public  0: group:everyone deny delete drwxr-xr-x+  6 smcho  staff     204 Feb  1  2010 Sites  0: group:everyone deny delete   What those appended messages mean? Why do I have them for some of the files? I don't remember doing anything particular for them.

I am using Mac OSX. When I type ls -l I see something like   drwxr-xr-x@ 12 xonic  staff    408 22 Jun 19:00 . drwxr-xr-x   9 xonic  staff    306 22 Jun 19:42 .. -rwxrwxrwx@  1 xonic  staff   6148 25 Mai 23:04 .DS_Store -rw-r--r--@  1 xonic  staff  17284 22 Jun 00:20 filmStrip.cpp -rw-r--r--@  1 xonic  staff   3843 21 Jun 21:20 filmStrip.h   What do the @'s mean?


I know this is simple, but I don't know very much at all about series, and I'm wondering how it's shown that:  $$ 1 + 2 + 3 + \cdots + (n - 1) = \frac{n(n - 1)}{2} $$

Apparently $1+2+3+4+\ldots+n = \dfrac{n\times(n+1)}2$.  How? What's the proof? Or maybe it is self apparent just looking at the above?   PS: This problem is known as "The sum of the first $n$ positive integers".


I'm afraid I'm missing something because the 0% tax bracket for capital gains seems too good to be true.  Everything I'm reading (e.g. "The zero percent tax rate on capital gains applies to people in the 15 percent marginal tax rate or below. In 2018, that applies to married tax filers with taxable income up to $78,750, and single tax filers with taxable income up to $39,375." at ) says that my capital gains tax rate is dependent only my income tax bracket.  In other words, say I have $2 Million worth of a mutual fund, which I bought more than a year ago for $1 Million (i.e. long-term capital gains of $1 Million).  If my income this year is $40,000 and I sell all holdings in this fund, I will pay $150k of capital gains tax.  However, if my income is $38,000 and I sell it all, I pay nothing.  Is this correct? If not, what am I missing?

First, my understanding is that the long-term capital gains tax rate is 0% for those whose marginal rate on ordinary income is 10% or 15%, and (ignoring the highest 39.6% bracket) the rate is 15% for everyone else. (See  and .)  My interest is in what happens at the crucial break between the 15% and 25% bracket, which is $73,800 for married/joint returns in 2013 (and presumably will be higher in 2014, though I haven't been able to find out what that is or if it has even been set yet). Let's say a household has $64,000 in wage income, and sells stock for a $10,000 profit.   Does their income for the purposes of establishing their tax bracket go to $74,000? If so, is the entire $10,000 profit subject to the 15% long-term capital gains rate? Is any part of the wage income subject to the higher marginal tax rate?   Since the amount of income subject to the higher marginal rate is, well, marginal, part 3 seems somewhat less important than part 2. The real issue is whether the capital gains rate hits the entire profit, since, in that case, it seems the household should only sell enough stock to generate a $9000 profit, and sell the remainder in a future year.


Suppose you made a lightsaber shaped like a Y, and in a battle fought with the one going straight. If you activated the other blade when you and your foe crossed blades, it would go right through them before they could block it, right? Is this possible?

Has a  ever been fictionalized previously in the Star Wars universe of any canon? Or is this a new saber technology completely written for the new Star Wars film?  I'm unsure how Disney works the canon now in the Star Wars universe. I did find this article on the , but I'm not sure how canon that article is.


How can I make the result of one command to be an argument of another?  I'm trying to kill child process by pid of parent process and use for it pgrep  Example: pgrep -P <PID>  But after I need to kill the PID which I get from pgrep  pgrep -P <PID> | kill  - it doesn't work(  Thank you!

To create a playlist for all of the music in a folder, I am using the following command in bash:  ls > list.txt   I would like to use the result of the pwd command for the name of the playlist.  Something like:  ls > ${pwd}.txt   That doesn't work though - can anyone tell me what syntax I need to use to do something like this?  Edit: As mentioned in the comments pwd will end up giving an absolute path, so my playlist will end up being named .txt in some directory - d'oh! So I'll have to trim the path. Thanks for spotting that - I would probably have spent ages wondering where my files went!


Let $N$ be a proper class model of ZFC and $x \subset N$ a set. Show that  there is a set $y \in N$ such that $x \subset y$.   If $x \subset N$, I think that by the downward's part of Löwenheim-Skolem, we can find an elementary submodel $y$ of $N$ such that $x \subset y$. But how would I conclude that $y \in N$? It seems like I'm missing something trivial but I can't figure out what exactly.   Note: A hint to point me to the right direction would be more appreciated than a complete answer.

I so stuck with a problem of set theory. But first a recursive definition:   Define $R_0=\emptyset$ If $R_\alpha$ is defined, then $R_{\alpha+1}=\mathcal{P}(R_\alpha)$ (the power set). For a limit ordinal $\gamma$, if $R_\alpha$ is defined for all $\alpha<\gamma$, then define $R_\gamma=\displaystyle\bigcup_{\alpha<\gamma} R_\alpha$   We define $\text{BF}=\displaystyle\bigcup_{\alpha\in\text{OR}} R_\alpha$ (the class of well founded sets).  Next, my problem     Take $A\subseteq \text{BF}$ a proper transitive class such that $(A,\in)\models\text{ZF}$. Prove that $A$ is almost universal.    I think that the exercise is false because if it was true, then we could conclude that the strongly inaccessible cardinals doesn't exists. This because if $\kappa$ is strongly inaccessible then $R_\kappa$ satisfies the hypothesis but $R_\kappa$ isn't almost universal. I really appreciate any hint or/and suggestion.   Edit: my counterexample is wrong. But, then, how can I solve the exercise?


To my knowledge if you calculate the coordinate time (time experienced by an observer at spatial infinity) it takes an infinite amount of time for an object to fall past the horizon of a Schwarzschild black hole. Doesn't this imply that it takes an infinite amount of coordinate time for a Schwarzschild Black Hole to form since the last bit of in-falling matter won't ever ross the horizon as observed by someone at spatial infinity? If so, is it possible for other types of black holes (Kerr etc.) to form in finite coordinate time?

One thing I know about black holes is that an object gets closer to the event horizon, gravitation time dilation make it move more slower from an outside perspective, so that it looks like it take an infinite amount of time for the object to reach the event horizon. It seems like a similar process should slow the formation of the black hole itself: As the star collapses, its gravitational time dilation make itself collapse more slowly. This make me wonder, are what astronomers claim to be black holes really black holes, or are they stars that progressively make themselves more similar to one without actually reaching the stage of having an event horizon?  EDIT: Contemplating one answer, I realize the question is ambiguous. What does finite time mean in general relativity. Here is a less ambiguous question: Is there a connected solution of 3+1 dimensional general relativity with one space-like slice not have a singularity, and another space-like slice having one.


I want a desktop-like full-page width layout. Some menu at the top (uknown height, depending on the content),  and div underneath that takes ALL the available space in viewport.    div {   padding: 0px }  html, body {   height: 100%;   padding: 0px;   margin: 0px; }  .outer {   background: olive;   height: 100%; }  .menu {   background: orange; }  .should_fill_available_space {   background: brown; }

     Lorem Ipsum Lorem Ipsum Lorem Ipsum

     Brown color should go all the way down

     I've got a codepen for this case:   I want should_fill_available_space go all way down, as in the case where menu would have height:10% and should_fill_available_space have 'height:90%`.

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

...

...

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


I made a comment on YouTube and want to see if someone replied to it.

I posted something the other day and wish I could find the video again. Is there a way I can see all of my comments?


I often come across interesting new questions which don't have any answers yet. To further my knowledge, I would like to revisit these questions when they do have answers.  I would absolutely love it if a feature could be implemented where one "subscribes" to a question and gets some type of notification when either the question is answered, or an answer is accepted.  These notifications could form part of the other notifications in your inbox.  What I do at the moment is "favorite" questions with the hopes of (a) remembering to look at questions that I've previously "favorited" and (b) that the questions do in fact have an answer now.  I think such a feature could go a long way in promoting learning and knowledge sharing over and above the questions that you ask yourself.  Would love to hear what the community thinks of this.  Note: I posted this question on the Electrical Engineering meta here . It could be useful for all sites though.

Right now there isn't a great way to monitor the questions that I am interested in following. What I seem to do now is go to my recent history for questions I have commented on, and then link to the questions from there. The problem is, if I am really interested in a question, I have to monitor it closely. Sometimes I will "favorite" a question so it is easier to access more quickly, because I do not have a lot of favorites. But favoriting is not the right thing to do. I think you should only favorite a question if you really really like it, not to make it easier to follow.  I propose that you can mark questions as "interested" or something like that. What this means, is that you will get notifications for everything associated with a question: any time a new answer is posted, the answer/question is edited, and any comments to any of the answers (or question). This would make it much easier to follow questions. Especially if someone adds a new answer or comment way down the road, after you have long forgotten about the question.  It would also be nice if such a feature allowed you to write a sentence or two to associate with the question to remind you about something. In fact, if this is done, we could just use this feature to implement  to allow an edit to notify downvoters. Instead of that specific feature, you can mark a question as interested after downvoting and add a comment, "remove downvote when fixed".  What do you all think? Do you propose a better way to manage monitoring questions of interest? (The other thing I do is keep a bunch of browser tabs open with questions I am following... and this is messy :-( ).


If $H^2(\mathbb{D})$ is space of all analytic functions whose series of taylor coefficient is absolute square summable and $\phi$ is analytic in $\mathbb{D}$,then $\phi H^2 \subset H^2$  if and only if $\phi$ is in $H^\infty$.  Not able to solve it through elementary arguments. can't think of what theorem of functional analysis can i invoke. any hints ?

Let $H$ be a Hilbert space of analytic functions.  Define the multiplier algebra of H in the following manner:  $M(H)=\{ \phi \in H  :  \phi h \in H, \forall h \in H \}$  It is mentioned in countless places that the multiplier algebra for  $H^2=\{f \text{ analytic on the disk}, f= \sum a_nz^n : \sum |a_n|^2 < \infty \}$  is $H^\infty$, the space of bounded analytic functions on the unit disk.  It is obvious that $H^\infty \subset M(H^2)$.  My question is how does one prove the other inclusion?


I have the following code:  print ("Cost: %f per %s" % (mrate[choice], munit[choice]))   Output:  Cost: 25.770000 per 10gm tube   How can I get it to round to two decimals while printing, so that I get 25.77 in the output?

I want a to be rounded to 13.95.  >>> a 13.949999999999999 >>> round(a, 2) 13.949999999999999   The  function does not work the way I expected.


My Laptop has 3 primary partition and 1 logical partition (which is common share among the 3 primary partition). 1st partition is with Windows 7, 2nd with Windows 8 and i intend to install 3rd with Ubuntu. I have a boot menu (using boot-us boot manager) to show this 3 partition separately when i switch on my laptop.  1) Please advise me the steps how to install Ubuntu into 3rd partition on only without damaging any of my other partition (E.g. 1st, 2nd and logical partition to be intact).  2) How do i change or fix the mac address (to a new one) in ubuntu (via menu or command line)?  Thanks in advance Saha

I currently have Windows 7 on my computer and I want to install Ubuntu alongside Windows safely.  Could someone please provide clear instructions?


I am using 20.04 GNOME. I tried to delete VLC with aptitude, which also somehow deleted h.264 decoder required to play some videos.  So I can't play videos on my machine any more. I've downloaded everything from h.264 as sudo apt install gstreamer1.0-libav, sudo add-apt-repository ppa: mc3man / trusty-media. They appear as downloaded but there is no h.264.  How do I install h.264 decoder so I can play the videos again?

Where do I get the MPEG-4 AAC decoder, and the H.264 decoder.  How to install them and play the multimedia?


I'm having a hard issue on a server, and I get no clue of what is happening nor where to search to debug it.  Here is my problem : When I run any command such as :  systemctl start httpd.service   or  systemctl -a   or (apparently) any systemctl linked command, I get the following message :  Failed to get D-Bus connection: Connexion refusée   Running ps ax | grep dbus returns:  403   ?     Zs 33:44 [dbus-daemon] <defunct> 25673 pts/2 S+ 0:00  grep --color=auto dbus   If you have any clue on it, let me know ! thanks

I'm trying to list services on my CentOS image running in Docker using  systemctl list-units     but I get this error message:  Failed to get D-Bus connection: Operation not permitted   Any suggestions what the problem might be?


I don't see why the cartesian product of two sigma-algebras is not always a sigma algebra ($\mathscr{B}(\mathbb{R}$ is the Borel sigma-algebra).

When reading the book Measures, Integrals and Martingales written by R.L. Schilling, I saw a statement as below: $$\mathcal{A} \times \mathcal{B}:= \{A \times B: A\in \mathcal{A}, B\in \mathcal{B}\}$$ where $\mathcal{A}$ and $\mathcal{B}$ are $\sigma$-algebras, is not $\sigma$-algebra in general.  However, I cannot construct a counterexample. Could anyone offer help here?  Kind regards


I am trying to access a variable that I made inside of a function on the outside. This is what I did:      def add(a,b):         v = a + b         print(v)      add(5,5)      print(v)   However, it tells me that it is not defined when I try to print it outside of the function. I then proceeded to create the variable outside of the function first, and then change it inside of the function. This is what I did for that:      v = 0     def add(a,b):         v = a + b         print(v)      add(5,5)      print(v)   In this case, it just printed out 0 instead of 10 on the last line. Is there any way to keep the changes to variable while it was inside of the function instead of it staying the same?

How can I create or use a global variable in a function?  If I create a global variable in one function, how can I use that global variable in another function? Do I need to store the global variable in a local variable of the function which needs its access?


I need some support with one problem 🙂 System messages in B2B web applications, specifically about them being ignored by users. Can you recommend any references or share your experience in designing them? System messages - I mean messages related to the operation of the system, namely: information about errors in the database information about upcoming deadlines warning about unsaved user actions information about the timeliness of data and the possibility of their supplementation  That is, partly about situations not resulting from the user action but from the system. The assumption is - message recognition, invasiveness in the scope acceptable by the user, creating the feeling of importance for safety and work in the system (but not to treat these messages as a buzzing disturbing fly) Thanks in advance for your help

I am working on ux for a desktop application for users. I am looking to find out more information, answers, best practices when it comes to handling notifications of actions and other alerts within a desktop application. Obviously I have seen how StackExchange handles notifications but since this is a desktop application instead of web it is a question I wanted to source.  Included is an image in this post that will display the two options I have been looking at. Both options seem to be the most common display areas that I have researched as well as seen active in many other applications. Currently the standalone desktop application opens to the default 1024x768 size but also has the ability to be scaled fullscreen to any size window the user is using. What concerns me is when a user full screens the application to a size such as 2560x1440 and a notification displays I don't want them to miss this notification.    Option 1: In my mockup the notification bar alerts the user by sliding down from the top of the desktop application. The left and right arrows inside the notification represent the ability to scroll back or forward to previous notification messages. The notification would have a 4 Second display time before auto hiding or the user has the ability to click X to close.  Note: This notification would cover the top menu navigation bar when sliding down.  Option 2: In my mockup the notification bar alerts the user by sliding up from the bottom right of the desktop application. The left and right arrows inside the notification represent the ability to scroll back or forward to previous notification messages. The notification would have a 4 Second display time before auto hiding or the user has the ability to click X to close.  Note: This notification would cover only minimal content display.  So my questions:   Are the options I am displaying the best solutions for users to see the notification without covering up to much content and ruining the experience? Is one option losing the users vision over the other? Would there be better areas or ways to handle these notifications in a desktop application that I am missing?


k am a Gambian national traveling to Gambia do I need a  four hour transit visa to morroco Cassablanca

I am travelling from Montreal (Canada) to Beirut (Lebanon) and transiting in Casablanca Airport (Morocco) for 8 hours. I currently hold a valid Canadian entry visa and study permit. My passport is Syrian. Do I need a Moroccan transit visa?


I've recently tried the tikz wheel from this other thread:  - it all works fine until I switched polyglossia to german. This fails with  Extra }, or forgotten \endgroup.  \documentclass{article} \usepackage{polyglossia} \setdefaultlanguage{german} \usepackage{graphicx} \usepackage{tikz} \begin{document}     \begin{tikzpicture}         \pgfmathparse{(5? "west" : "east" )}  % Apprently these quotes are  the culprit.     \end{tikzpicture} \end{document}  This works \documentclass{article} \usepackage{polyglossia} \setdefaultlanguage{german} \usepackage{graphicx} \usepackage{tikz} \begin{document}     \begin{tikzpicture}         \pgfmathparse{(5? 5 : 4 )} % This does not make sense but works     \end{tikzpicture} \end{document}  As we can easily see the quotes around east seem to be problem. How can I bypass this?

The MWE below gives error language@active@arg" has extra }.  \documentclass{article}     \usepackage[T1]{fontenc}     \usepackage[utf8]{inputenc} \usepackage[english,slovene]{babel}%     \usepackage{tikz} \usetikzlibrary{quotes}  \begin{document}     \begin{tikzpicture} \draw (0,0) edge ["right", ->] (2,0);     \end{tikzpicture} \end{document}   Cause for it is option slovenian in babel which seem to redefine " somehow (if I remove this option, MWE work fine). Please, help me fix this error.


I know that $$ \int_{-\infty}^\infty e^{-x^2} dx = \sqrt{\pi}, $$ and clearly this integral is invariant under translation along the real axis. But today I learned that $$ \int_{-\infty}^\infty e^{-(x+ik)^2} dx = \sqrt{\pi} $$ holds for any choice of constant $ k \in \mathbb{R}$, so we even have translation invariance along the imaginary axis. Why is that?

How to prove $\int_{\mathbb{R}} e^{-\frac{(x+it)^2}{2}}dx=\sqrt{2\pi}$ for any $t\in \mathbb{R}$? I only obtained the case that $t=0$, $\int_{\mathbb{R}} e^{-\frac{x^2}{2}}dx=\sqrt{2\pi}$.   Thanks.


Induction on $n$:   If $n=1$, then $A_{n+2}=A_{3} \simeq \mathbb{Z}_3$ has subgroup $1 \simeq S_n = S_1$. Assume for some $n>1$, $S_n \simeq H$ for some $H \leq A_{n+2}$. I want to show that $S_{n+1} \simeq H'$ for some $H'\leq A_{n+3}$.  Note that $H \simeq S_n \leq S_{n+1}$, and by inductive hypothesis $H \leq A_{n+2} \leq A_{n+3}$. I guess if I can show that $S_{n+1} \simeq A_{n+2}$ then it will complete the proof, but I don't even know if that is a true statement.

I am trying to prove that for all $n$, $S_n$ is isomorphic to a subgroup of $A_{n+2}$.  Say $S_n$ acts on $\{\alpha_1,...,\alpha_n\}$ and $A_{n+2}$ acts on $\{\alpha_1,...,\alpha_n,\alpha_{n+1},\alpha_{n+2}\}$.  Let $\sigma \in S_n$ and let $\phi: S_n \to A_{n+2}$ be given by $\phi(\sigma)=\sigma$ if $\sigma$ is an even permutation, and $\phi(\sigma)=\sigma(\alpha_{n+1}\alpha_{n+2})$ if $\sigma$ is an odd permutation.  This way $\phi(\sigma) \in A_{n+2}$.  Now, let $\sigma, \rho \in S_n$.  Then $\phi(\sigma \rho)=\sigma \rho (\alpha_{n+1}\alpha_{n+2})$.  Also, $\phi(\sigma)\phi(\rho)=\sigma(\alpha_{n+1}\alpha_{n+2})\rho(\alpha_{n+1}\alpha_{n+2})=\sigma\rho$.  So, $\phi(\sigma \rho)$ does not seem to equal $\phi(\sigma)\phi(\rho)$.  But the idea is that we want $\phi(S_n) \cong S_n$, and $(\alpha_{n+1}\alpha_{n+2})$ does not permute any members of $\{\alpha_1,...,\alpha_n\}$, so $\phi(\sigma \rho)$ and $\phi(\sigma)\phi(\rho)$ are equal as permutations on this (sub)set.  This feels a little subtle to me and I'm not sure if my idea is valid or not.  If it is not, can this proof still be saved?  I appreciate any thoughts on this.  Thanks.


I'm flying Delta and making a connection at LAX between a domestic flight to a departing international flight? Do I need to reclear security and/or checked bags? Is the 1.5 hours that Delta reserved sufficiant? I arrive at 11 pm on Wednesday and leave at 12:30 am, and have a single ticket for the entire journey.

I am flying United Airlines to Melbourne from O'Hare (same ticket). There is a 1 hour 10 minute layover between my ORD-LAX and LAX-MEL flights.  Is this enough?   My research so far on this:   My ORD-LAX flight is United. So, I guess it should arrive at Terminal 8. I checked FlightAware and it seems that my LAX-MEL flight also takes off from Terminal 7 (Not TBIT).  Terminal 7 and 8  I have no checked baggage. Just a backpack.  Since ORD seems to be weather sensitive, this trip is in first week of May so hopefully, weather-related delays shouldn't occur (?).


I want to create multiple files at a time using names from a file list.txt, as well as the text in each files. Suppose I have a list.txt containing some id. numbers, now I want to make separate files using that ids as the name (e.g. EOG090W002U_M0.ctl, EOG090W00C1_M0.ctl, EOG090W00DC_M0.ctl). Also, the contents of the files need to be changed accordingly.  Sample list.txt:  EOG090W002U  EOG090W00C1  EOG090W00DC  EOG090W00DE  EOG090W00E5 EOG090W00HR  EOG090W00MH  EOG090W00MS  EOG090W00PB  EOG090W00U4 EOG090W00UK  EOG090W00WM  EOG090W00WR   For example the desired content of EOG090W002U_M0.ctl, EOG090W00C1_M0.ctl file will be  seqfile = EOG090W002U_p.phy treefile = Sametree.txt outfile = EOG090W002U_M0_mlc  getSE = 0 RateAncestor = 1 Small_Diff = 5e-7 cleandata = 1 fix_blength = 2 method = 0   Or  seqfile = EOG090W00C1_p.phy treefile = Sametree.txt outfile = EOG090W00C1_M0_mlc    getSE = 0   RateAncestor = 1   Small_Diff = 5e-7   cleandata = 1   fix_blength = 2   method = 0   Here, seqfile and outfile is going to be changed according to the list.txt but other texts in the file will remain the same.   Thanks

I want to create multiple files at a time using names from a file list.txt, how can I do it?  Sample list.txt:  EOG090W002U EOG090W00C1 EOG090W00DC EOG090W00DE EOG090W00E5 EOG090W00HR EOG090W00MH EOG090W00MS EOG090W00PB EOG090W00U4 EOG090W00UK EOG090W00WM EOG090W00WR   Suppose I have this list.txt containing some id-numbers. Now I want to make separate files using these ids as the name (e.g. EOG090W002U_M0.ctl, EOG090W00C1_M0.ctl, EOG090W00DC_M0.ctl). Also, the contents of the files need to be change accordingly. For example the content of EOG090W002U_M0.ctl, EOG090W00C1_M0.ctl file will be   seqfile = EOG090W002U_p.phy treefile = Constant.txt outfile = EOG090W002U_M0_mlc   or  seqfile = EOG090W00C1_p.phy treefile = Constant.txt outfile = EOG090W00C1_M0_mlc   where *.phy and Constant.txt will be provided in the same folder.


I am trying to develop a shopping cart and i am stuck with the following issue. i am creating a new product dynamically using jQuery. The following piece of code adds new product to the cart:          var productAdded = $('
<button href="#0" class="button2" id="'+ id +'">' + product_name + '</button>	<select id="cd-product-'+ id +'" name="quantity"><option value="1">1</option><option value="2">2</option><option value="3">3</option></select>	' + product_price + '
');     cartList.prepend(productAdded);   As you can see above i am creating a new 'button' within javascript. For that element click event is not firing.  $(".button2").click(function(e) {                     e.preventDefault();                      $("#add_product_comment").dialog({                       buttons : {                           "Άκυρο" : function() {                           $(this).dialog("close");                         },                         "Αποθήκευση" : function() {                           setInterval(function(){}, 1000);                            $( "#add_product_comment" ).dialog( "close" );                           // $('#two').load(document.URL +  ' #two'); using ajax reload div                                                    }                       }                     });                      $("#add_product_comment").dialog("open");                     $('.ui-widget-overlay').css('background', '#000000');                    });   Any help will be really appreciated.

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


I'm using \hl{} from soul  package to highlight some words in my document. However, I'd like a "realistic" highlighting, simulating the result of a "manual" note: a not-so-regular rectangle with "waves" here and there.  I think a long time ago I saw something like that here in StackExchange but I could't find it.  Edit  Yes, this is a duplicate of . I can't understand all the code but it is what I need. Just one more thing: is there a way to recreate the darker spot corresponding to the point where the highlighter is removed from the paper, like in the (exaggerated) image?    I don't really need it but it would make the document look more hand-drawn.

LaTeX has soul. ConTeXt, of course, , where you can put sweet hightligher under your text for free!    In the pictured example, you can see highlights that not only highlight, but that do it with cool edges that look so good, you can smell fumes! The fearless author says he'll show how that was done in another post; this one shows only how to lay down a straight, yellow box. But, it is possible to do word-wrapped highlighting with cool-shapped boxes within ConTeXt, presumably.  The trouble for me is that getting into the ConTeXt world is steep climb right now, given the state of documentation and the flux of changes, so I need to continue with LaTeX. But the real problem is that now I can't live without the Organic-Looking Highlights of Awesomeness in that picture!  As I said, Non-Organic-Looking Highlights of the Ordinary are easy with the soul package:  \hl{Some awesome text that word wraps fine.}   It just taunts me on the page with its straight lines. So, if I sacrifice word wrapping, I can use PGF/TiKz and create the following macro:  \newcommand\hl[1]{%     \tikz[baseline,%       decoration={random steps,amplitude=1pt,segment length=15pt},%       outer sep=-15pt, inner sep = 0pt%     ]%    \node[decorate,rectangle,fill=navcolor,anchor=text]{#1\xspace};% }%   Which creates something like this:    Now, my color is too dark and my randomness needs adjusting, but you see that a similar effect could be achieved.  My trouble is that I don't understand TeX enough to dig into the Soul package and add the TiKz/PGF goodness that it so sorely needs. So, I leave it to you guys. Anyone want to tackle this?   Or is it yet another piece of fruit, just a touch out of reach, that shall have to wait until ConTeXt settles down?


Why this is not a duplicate: This question is different than   My issue was caused by a missing attribute on a Lightning component. It would be nice to see some kind of error indicating a required attribute is missing instead of a generic error message.   Original question:  When I include my custom component (.cmp) inside of a standalone lightning app page (.app), I get a generic error:    This page has an error. You might just need to refresh it. Aura.loadComponent(): Failed to initialize application. An internal server error has occurred Error ID: 1165864723-88707 (1861465479)  To find out more details about what is causing the issue, I have:   Enabled debug mode so that I get un-minified js code.  Disabled caching  Installed Lightning Inspector for Chrome    When I load the page, I do not see errors in the Google Dev Tools console or Lightning console. I'm lost as far as how to find out details about the error...  Code  <aura:application extends="force:slds" > <!-- Header --> <lightning:layout class="slds-page-header" >     <lightning:layoutItem padding="horizontal-small">         <lightning:icon iconName="custom:custom54" />     </lightning:layoutItem>         <h1>          Friends with Boats     </h1> </lightning:layout> <lightning:layout>         <c:BoatSearchForm />  <!-- the error happens when I include this component--> </lightning:layout>  </aura:application>   How I debugged the issue   To find out the cause, I commented out the contents of the entire component and uncommented different sections until I ran into the problem. The error happened when I tried to add a  component to the page. The problem -  a missing required attribute 'label'.       <lightning:select>  <!-- missing attributes: 'name' and 'label' caused the error -->             <option value="">All types</option>     </lightning:select>   Takeaways:   If a lightning component requires certain attribute and it is missing, you will get a runtime error on a standalone .app page.  A lightning markup code can be saved even though it might be missing required attributes that cause runtime errors. Currently, Salesforce does not show a detailed error for invalid lightning markup. You only see a generic error. Adding a component to an App page through App Builder does not generate this error. Instead, when you open an app page in a tab, it generates a 'WARNING' in the Google Chrome Development Console. Is this a bug or by design?

I have seen and read many posts in regards lightning component errors and realized there are no questions actually asking how to debug them. I recently stumbled upon:         and decided to post this question in order to get a detailed step by step guide on doing so for lightning components hoping this will help others in the community (and myself as well).  I am aware there is excellent documentation in the developer docs and blogs:     by Peter Knolle   Additionally, if you would like to include any tools you use for doing so, such as:      By all means do so


I program I was using to out put some files apparently did not understand the short cut "~" (directory) very well and has done some trickery that has me confused.  Rather than put the files where I would expect them (/home/me) it has a made a folder in it's subdirectory called "~".  (someprogram/~)  drwxr-xr-x  3 me users 4096 Jan 30 09:34 ~  If I cd into it I get back to /home/me  Is this just a hardlink? I imagine if I try to delete it will will delete my home folder. How can I safely remove it and not delete everything?

I just noticed that I have a file called ~ in my ~-directory.  $ ls -la ~ ... -rw-r-----  1 x1 x1  733962240 Mar  1 17:55 ~ ...   Any idea how I can mv or rm it?


I have already read this answer . However I have tried that on Windows 10 and it didn't seem to change anything. Considering that the solution was from back in 2009, perhaps there is something else that needs to be done in order to get it to work. Any pointers would be helpful.   EDIT:  It seems that for this to work, you have to type the "+" key on the numeric keypad. What about those on a laptop and no numeric keypad?

One of my laptop's keys has fallen off. Is there any way I can remap another key to serve as that key?  I'll 'sacrifice' the other key because I never use it.


According to the player's manual, a character with intelligence = 10 who wants to make a multiclass wizard needs to have a minimum of intelligence = 13. If in the course of an adventure you find an object that increases your intelligence to 19 while it is equipped, does it meet the requirements or are the requirements supposed to be without magic or alterations, minimum characteristic base? In chapter 6 of the player's manual that possibility is not mentioned or I have not found it.

The multiclassing rules (PHB, p. 163) state:     To qualify for a new class, you must meet the ability score prerequisites for both your current class and your new one [...] Without the full training that a beginning character receives, you must be a quick study in your new class, having a natural aptitude that is reflected by higher-than-average ability scores.    Can the ability score prerequisite(s) for multiclassing be met by (long-term) use of a magic item(s) such as the Headband of Intellect (INT 19), Ioun Stones (+2 to various ability scores), etc.?  The phrase "natural aptitude" suggests nonmagical, but a character could have been using a magic item for years which seems virtually indistinguishable.


$$ \lim_{n\to \infty} \left(\frac{1}{n+1} + \frac{1}{n+2} + ..+ \frac{1}{2n}\right)$$  How do i find the limit by expressing it as a definite integral of an appropriate function via Riemann Sums?  I do know that for riemann sums  $\Delta x = \frac{b-a}{n}$ and $ x_i^* = a + \frac{b-a}{n}$  So i would need something like this   $$\lim_{n\to \infty}\sum_{i=1}^{n}\frac{b-a}{n}\cdot f\left(a+i\frac{b-a}{n} \right)$$  But how should i go about solving the question?

What is the sum of the 'second half' of the harmonic series?  $$\lim_{k\to\infty}\sum\limits_{n=k+1}^{2k}{\frac{1}{n}} =~ ?$$  More precisely, what is the limit of the above sequence of partial sums?