Suppose $G$ is a group of order $4$ and $x^2=e$ for all $x$ in $G$. Prove that $G$ is isomorphic to $Z_2\oplus Z_2$.  My attempt:  (1) Show that $G$ is abelian.  \begin{align*} \text{Take }x,y\in G.&\text{Then }xy\in G.\\ (xy)^2&=e\\ \text{Thus } (xy)^{-1}&=xy\\ \text{Also by socks-shoe property }(xy)^{-1}&=y^{-1}x^{-1}=yx\\\\\text{Thus we have }&xy=yx \text{ and $G$ is abelian}. \end{align*}  (2) Show that $Z_2\oplus Z_2$ is abelian. $$\text{This can be easily verified.}$$ (3) Define the isomorphism $\phi$  $$\text{Let $G$}=\{e,a,b,c\}\\ \text{Define } \phi \text{ from $G$ to $Z_2\oplus Z_2$ such that}\\ \phi(e)=(0,0)\\\phi(a)=(0,1)\\\phi(b)=(1,0)\\\phi(c)=(1,1)$$ $$\text{Clearly $\phi$ is one-one and onto.}$$How do I show that $\phi$ is operation preserving?If this is not the right way the proof is going, please post the solutions.

I have this homework problem.  It states:  By constructing the possible Cayley tables, list all groups where the underlying set has at most 4 elements, up to isomorphisms.  That is, no two groups in your list should be isomorphic.   I understand the basic use of Cayley tables in the sense that they are used to see what the operation on two of the elements becomes.  One group that I know that would fit this would be $\mathbb Z_4$.  I'm not sure how to list all of them and if there is a way to know if it will be isomorphic or not.


I'm making simple application for record internal leaves of my office. with this application I have to provide users to two HTML date fields for select start leave date and end leave date. At the same time I need to calculate how many days have in between user's selection also this count may exclude the weekdays. To do this i tried to use simple javascript with one of date fields onchange event but it's not working   this is the complete code with HTML I have tried        <form action='reqprocess.php' method='post'>             <input type="date" name="datepicker" class='form-control' id="startd" required/>
             <input type="date" name="datepicker2" class='form-control' id="endd"required />
             <input type="text" name='leavehmd' class='form-control' id="lhmd"/>
             <input type='submit' value='Apply' class='btn btn-primary' /> </form>               But when sect second date, on-change function not works and Input field suppose to fill with counted dates not populated. How can I fix this ?  or how can I achieve this via methods like ajax or jquery

How do I get the number of days between two dates in JavaScript? For example, given two dates in input boxes:  <input id="first" value="1/1/2000"/> <input id="second" value="1/1/2001"/>  <script>   alert(datediff("day", first, second)); // what goes here? </script>


Please excuse my noobs query, as I'm new to linux environment. I'm getting errors in sudo apt-get update  W: Failed to fetch http://deb.playonlinux.com/dists/precise/InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY E0F72778C4676186 E: Failed to fetch http://ppa.launchpad.net/pmcenery/ppa/ubuntu/dists/xenial/main/source/Sources  404  Not Found W: Some index files failed to download. They have been ignored, or old ones used instead.   There was some error in this ppa.launchpad.net/pmcenery, I found some suggestion after googling, it said me to remove the key by doing  sudo apt-get del Keyno. I did removed that still there are some errors, now it is saying there's no public key.  Please suggest how to get rid of this issue.

I added some extra repositories with the Software Sources program. But when I reload the package database, I get an error like the following:     W: GPG error:  trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 8BAF9A6F   I know I can fix it using apt-key in a terminal, according to the official Ubuntu documentation. But I would have liked to do it graphically. Is there a way to do this without using a terminal?


As per title, why Ubuntu with the 4k Monitors it has this strange managing/behaviour under the DPI called Fractional Scale. Exeample, I have the 4k Monitor where the Resolution it's 3840 x 2160, yes you can manage the words proportions, icons and so on, but will never be homogeneous proportions like as you set all the system with the DPI option. One thing that I noticed with Ubuntu, it's, with 4k Monitors you pass from 100% DPI (small for 4k) to 200% (big for 4k monitors), so if you wanna go in between you have to choose the Fractional Scale that allows you to set 125, 150 and so on DPI scale... But here comes in the way the problems, under the game sections and some software, because if you set 150 DPI scale the Fractional Scale Options it will keep the Monitor in Native 4k 3840 x 2160 but to scale everything in 150 DPI it will "let to think to the System" that you are under 5k Monitor as 5120 x 2880 pixels, and this you cannot reverse if you want keep 4k 150 scale DPI!!! So, the system it tells you that you are fine under 4k, but the Nvidia in detailed it tells that you are in 4k Monitor under 5k Resolution (as the games or software percept as well 5120 x 2880), and if you change it with Nvidia x Server Settings, you can cange temporary; but in the next reboot will go back in the same way 4k Monitor 5k Resolutions. And, if you are using some Games or Wine or even some software it behaves as it runs under 5k Monitor with the consequences of messy resolutions and increase the GPU Power because the GPU has to manage higher Resolution. My question, it's, why Ubuntu cannot manage it in better way as any other OS or Windows OS without using this "go around system for DPI options"? Technically there is some reason or it's just a limited implementation?

Is fractional scaling ( ) available in 18.04 LTS yet? I am waiting until this is available before I install.


Can heat be transfer from low temperature body to high temperature body? Because according to second law of thermodynamics it can be transfered. But how?

I hope this question isn't too simplistic but I've been in a discussion with someone who claims that no energy is transferred between a cool object and a warm one (either by radiation or conduction) because the 2nd Law of Thermodynamics states that heat always flows from hot to cold.  My intuitive understanding is that energy actually flows in both directions, but the net flow conforms to the 2nd Law as more goes from hot to cold than vice-versa. In effect, the 2nd Law is an emergent property of many interactions. Is this the case?  EDIT: I should add that I've researched as much as possible, but no sources seem to explicitly state anything but the standard 2nd Law statement. If the answer is can be found in a resource I can be pointed towards, I'd be hugely grateful and apologise for wasting anyone's time.


I have two images. One on black background and the other on white. How to pick a color to act like transparency mask? How to separate it and put in alpha?

I am working with very old model files that have BMP textures. The designers did not use a transparency in the textures or a separate alpha b/w texture. They used a specific color value that was then removed by the engine to create a transparency, similar to a chroma key. In this case, all textures used a bright purple/pink color.   I cannot modifying the original texture images by converting them to PNG and add an alpha. I would like to figure out how to do it all in nodes.  The goal is to have this value keyed out and transparent. I have been messing around in the shader editor and cannot figure this out.  I've also been looking around online and in this forum, but the only search terms I can think of are chroma-keying which only results in Compositing results, which I don't believe is what I'm looking for.  Here is an example of the texture (its very small) and it's context:      Any help or direction would be much appreciated!


Related, but not a dupe:   That questions discusses this scenario:   Player A plays Attack. Player B takes a turn, draws an Attack and plays it.  Player C has to take three turns.    That is clear. But in this scenario:   Player A plays Attack. Player B plays some other cards (Favour, See the Future or whatever). Player B plays Attack (so does not draw a card).   Does Player C now have to take four turns or three? Or should Player B have played the Attack as his first card?  An argument for Player C taking four turns is that Player B could have done exactly the same thing whilst not being under the influence of Player A’s Attack and force Player C to take two turns, so they are just stacking those two into the two from the first Attack. However, I felt that by playing cards, Player B was essentially taking a turn which should be completed by drawing a card. He could then play the Attack as his second go and force Player C to take three turns.

Scenario: P1 plays attack  P2 plays attack.  P3 has 4 turns on her. P3 plays a turn and draws a card. P3 has 3 turns left.  P3 plays her attack.   What happens?


I'm building a bibliographic index card, like the ones used in old libraries. So, I have a "bib" file with only one entry (because I'll print one at a time - this will be my reading list). I have made everything. But I need to retrieve the BibTex <entry key>, whatever it is (book, thesis, whatever). My aim is to use this  to automatically generate a barcode at the top of my index card. Cool humm. ;) The problem is that I cannot figure out how to read this <entry key> and put it in a string variable, using \def\mystring{<entry key here>}. This is my index card now:

Suppose I have a .Bib file with an entry like this: @InBook{lear, author = {Shakespeare, William}, bookauthor = {Shakespeare, William}, maintitle = {Collected Works}, booktitle = {Tragedies}, title = {King Lear}, volume = {1}, pages = {53-159}, ...  Important: it could be any other reference, because I'll deal with different Bib files with only one reference each one - they will be generated automatically by another program. I'm using Biblatex inside Overvleaf platform. My question is: Is it possible to retrieve the entryfield (that in the example above is the string lear) and use it to be passed as a parameter? Example: \def\mystring{{*var_entrykey*}}  Where var_entrykey content must be lear (refering to the example above) or whatever other entry depending the bib file I'll be using (remembering that all the Bib files will have only one reference).  The problem is that I don't know how to read the entrykey automatically, i.e. usually we need to know the entrykey to reference it, that's the normal use and obvious. But in this case, I need a hack to retrieve it  - and put it in a variable - without knowing it's content beforehand.  Warm regards


Why do I get .8499999999999943 and not .85 when I run print("My remaining total is:", 80.85 - (20*4))?

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


Find all finite fields making $f (x)=x^2+x+1$ irreducible.  Obviously, we have only two cases:   For each prime $p $, $f $ is reducible over $\mathbb {F}_p $. Then, for any $n\ge 1$, it's reducible over $\mathbb {F}_{p^n}. $ $f $ is irreducible over $\mathbb {F}_p $. Then, since the deg of $f $ is 2, $f $ is reducible over $\mathbb {F}_{p^{2n}} $ if $n\ge 1$.   So it suffices to classify the cases $\mathbb {F}_p. $ From a direct observation, $f $ is reducible over $\mathbb {F}_p $ iff $p $ is a factor of $n^2+n+1$ for some integer $n $. Can I reduce it more? I wonder if $f $ is reducible over $\mathbb {F}_p $ iff $p$ has the form $n^2+n+1$.

Find all primes $p>2$ for which $x^2+x+1$ is irreducible in $\mathbb{F}_p[x]$   Attempt. Since $x^2+x+1$ is of degree 2, it is reducible iff it has a root in $\mathbb{F}_p$. It has a root in $\mathbb{F}_p$ iff $x^3-1=(x-1)(x^2+x+1)$ has a root other than 1. The latter has a root other than $1$ iff $\mathbb{F}_p$ has elements of order $3$, which happens iff $3\mid |\mathbb{F}_p^{\times}|=p-1$, which happens iff $p\equiv 1\bmod 3$. So $x^2+x+1$ is irreducible iff $p\not \equiv 1\bmod3 $.   I am getting a different answer than my professor, who has $p\equiv 1\bmod 3$. If I am incorrect, were am I going wrong?  Update. Now I am unsure about my own reasoning. What if $1$ is a root of $x^2+x+1$? I don't know why I am considering roots of $x^2+x+1$ other than $1$ when $1$ can be a root.


I don't know if I'm the only person to find this out or not. But anyways I like the way wubi works so I was kind of mad that 13.04 didn't have it. But I was playing around, and I downloaded the Ubuntu 13.04 iso file and I extracted it to a folder, and surely enough after I extracted it, I went to that folder and in that folder I found awubi.exe so I double clicked it and it worked! Now I'm running Ubuntu 13.04 off of a wubi install and it works perfectly fine for me. This shocked me because I thought they had gotten rid of wubi installs after 12.04 but I guess it's still possible. I thought I would just share this with everybody.

I want to install 13.04 (or higher) using wubi, is that possible?


I have 2 bootable installations, one of them is broken, meaning I can't boot it but it does appear in the boot menu. I want to completely remove the broken one and merge its partition with the my current installation. How can I do this safely?  UPDATE:  I can't figure out how to merge sda1 and sda6, sda6 being my main partition.

So basically I have a pretty flooded Grub bootloader, with older linux versions, 3 operating systems and memtests. What I want is to leave the operating systems only. I need to know how to do it manually, and I need someone to tell me what should I be aware of when a new kernel is released. Thanks in advance.


One could use "direction" to describe this property, but it is too wide, and I would like to find a term that narrows it down further, to describe the property (of a direction) of being either to the left or to the right. So, you could say for example that the xx of the object yy is left, where xx is the name of the property. Or you could say, "the xx of parts of the brain determines whether they're dealing more with logical thinking, or more with artistic creativity".

If I take a shape and its mirror image, what is the word for the property in which the two differ? For example, they differ in position after a translation, or orientation after a rotation.  If the original shape had its vertices labeled clockwise, then this word would pick out whether or not the vertices remained clockwise or not (and would still apply for non-chiral shapes like squares where the mirror image would otherwise look the same).


When a person is ill because of cold, then we can say about him that      "He caught cold"    (in 1st p.: "I caught cold" or in modal "you can catch cold if you will not dress properly")  or      "He got cold"?    (in 1st p.: "I got cold" or in modal "you can get cold if you will not dress properly")  Normally I've used "got cold" but someone wrote me that she caught cold (she's not Native English speaker) and that's what brought me to ask my question here.   In addition, I would love to know about the usage of these phrases or corresponding phrases in in the main English speaking countries such as: US, Britain, Canada and Australia (AmE, BrE, CaE, AuE).

The questions here are not about meaning. They are about the usage of the verbs get and catch in the context of getting a cold.   says that get can be used to mean 'to become infected with an illness; to suffer from a pain, etc.' and gives the example:     I got this cold off you.   My grammar confirms the dictionary and talks about get a cold in the chapter dedicated to the verb get. It also brings catch a cold to exemplify English collocations.  However, I was browsing the Internet and it seems that, at least for Americans, if we say I got a cold it is kind of uneducated. I caught a cold is what we should say.  1) Is this true? Is it better to say I caught a cold than I got a cold? 2) If it is the case, does this apply to British English as well?


I was in labyrinthian and was disarmed, as I had never been disarmed before I just thought my Mehrunes Razor had been Unequipped I promptly pulled out chillrend and continued on to get the staff I was there for. Upon arrival at winter hold I realized it was not in my inventory  I am now crawling through labyrinthian trying to find it.  If you are disarmed, and leave the area without retrieving your weapon, will it still be there when you return?

With the Thieves Guild missions to steal X worth of items from Y, I find myself with a lot of useless items that aren't even worth selling.  So usually I just stop and drop everything on the ground. Unfortunately, this means that Riften now has random piles of plates and goblets and other random garbage everywhere. I guess they don't have sanitation workers in Skyrim.  Will these items eventually disappear or will I have to do a special thief "mission" to steal all the garbage off the ground and dump it in a container?


In the original plans for the animated Beauty and the Beast, the Prince was to be a Duke. If they had kept that in, Belle would’ve been a Duchess when she married him, so would she still be a Disney PRINCESS? Edit: Also, would Duke Adam be ruling over a Duchy in France if he was a Duke?

Some characters in Disney movies are labelled as Princesses. Is there an official list of these Princesses? Rules to qualify, requirements that must be met?


When academic committee consider an applicant for postdoc or tenure track positions, how much do they care about where the applicant got his Ph.D? Suppose two applicant have similar accomplishments in their research, will the one who graduated from a more prestigious school gets the offer first?

What I'm trying to understand is, to what degree does the status/rank of the University (where one completes his/her Ph.D) matter while shaping his/her career after graduation? I would like to know the weight given to one's school in both the following cases:   While applying for post-docs/faculty positions in academia While applying to industrial research labs   For instance, I've read on some forums (I can't locate the link now) that while considering prospective applications for tenure-track faculty positions, very few Universities accept a candidate who has completed his/her Ph.D from a lower ranked school having a lesser "brand" value, irrespective of the fact whether he/she has published equally original work as his/her counterpart from an Ivy league college. How much truth is in this statement? It would be really great if someone already in academia, either as a newly-accepted faculty or someone on the Faculty Hiring committee could share their experiences/statistics on this regard. I'm simply interested to know the answer, without commenting at all on whether such a practice is justifiable.  Similarly, what about recruitment to internationally acclaimed research labs (like  or ) - what importance do they place on the pedigree of a candidate's college, before taking into consideration what they published ?  I'm personally interested in answers related to the field of Computer Science (theory), but the question is applicable to any prospective grad student in any discipline in my opinion. Feel free to share your personal experiences post-Ph.D in detail, as that would give me (and future viewers of this question) about what its like to carve a career once you are out of school!


Some of you might have heard rumors, but right now, Science Fiction and Fantasy has  going on. We are currently at exactly 10 nominees with one day left in the nomination phase.  As it stands, if we get no more nominees, we jump right to the election phase. If we get one more nominee, we'll instead split between a primary and election phases. If we do go to a primary, it will probably be with just 11 nominees, and we will spend the next four days decided which one candidate gets eliminated.  Somehow, that seems a bit harsh on whomever that person is. While technically the primary is selecting the top 10 out of 11 candidates, the impression it gives is that we're picking "the worst" candidate.  Perhaps the rules could be tweaked such that the primary process isn't triggered by just having "one too many" candidate. For example, if there are more than X candidates, it triggers a primary where (.75 * X) candidates are selected. That is:   11 candidates -> no primary 12 candidates -> primary -> 9 candidate election

When an election gets more than 10 nominations, primaries are held to select the top candidates. Currently, primaries select the top 10 nominations so that no election will have you choosing among more than 10 candidates, but that can be awkward when you are asked to pick the top 10 candidates... . Spending three days throwing out one candidate sound both awkward and a waste of time. I think it would make more sense if primaries were still triggered upon reaching 11 nominations, but then they should pick the top (say) 8 candidates. This would make primaries always meaningful (cutting down on the amount of choices to the most prominent/popular choices) but never awkward (you'd always prune at least a few people, and not just one or two).  As proof, I ran the elections of Stack Overflow, Programmers, Super User and Gaming, with and without the users that came up 9th and 10th at the primaries. The differences are negligible. Methodology The full ordering of the candidates can be obtained by running the elections with 1, 2, ..., 10 seats. The 4th place candidate is the one that wasn't elected with 3 seats but is elected with 4. To simulate what would happen when the 9th and 10th users in the primaries (marked yellow in the tables) would have been excluded in the elections, I used the "Withdraw candidates" option of OpenSTV, so that any preference for the two users is discarded correctly and the relevant ballots are updated correctly. Results In no cases was the ordering of the remaining candidates changed by this, and only 50 votes from Stack Overflow (out of 4,269) were completely removed as the result of ignoring the bottom two candidates. I think it is fair to conclude that running an election with 8 or 10 candidates makes no practical difference. Data porn


So lets say I am playing a level 12 Wizard, and I am in a dungeon when I find a spell book. So something similar happened in a quest I was playing and then the my DM said something along the lines of "So you can copy the spells in the book to your own book and you will have to buy...". So this made me think must I copy these spells to use them or can carry around both spells and cast from them whenever I want? Am I limited to spells from my book or can I use all spell books for spells

To prepare spells from another wizard's spellbook you have to be able to read it. Since there is no read magic spell (like in previous editions), how does a wizard read another wizard's spellbook?


I was trying to install Ubuntu on my Pc. I am having windows 10 as my current OS, I also want Ubuntu in my Pc. I successfully downloaded Ubuntu from its webpage and booted it to my pendrive.  I created an unallocated space for installing Ubuntu -   Then i restarted my pc and opened boot, changed uefi to legacy (I have Gigabyte). Then i ran my Pendrive. I got the installation page of Ubuntu. But there were no option for dual-booting Ubuntu with my Windows 10 OS.    I want to dual-boot Ubuntu with my Windows 10 so that i can use both without any loss. Please help me with this issue.

I've got an HP Pavilion Touchsmart notebook that came with Windows 8. I've upgraded to 8.1, and now I want to dual-boot an Ubuntu distribution with Windows 10. When dual-booting with Windows 8.1, the Windows Boot Manager always took priority, even after installing GRUB. What do I need to do to get GRUB to be the default bootloader instead of Windows Boot Manager?


14.04, Gnome Flashback desktop. How to create desktop shortcut for Firefox or other applications? Preferably, without installing additional components.

Is there an easy way to create a desktop shortcut for an application in Unity? The ability to right click or drag and drop icons to the desktop in Unity does not seem to be there.


My aim is to call source(highlighted by minted package) in one of the input.tex file instead of master tex.  This one does not work :     \documentclass{uoyths} \usepackage{minted} \begin{document} \input{chap0.tex}   %Content      \begin{mainMatterEnv}          \CallMintedCodeFromAnotherFile{}          \end{mainMatterEnv} \end{document}   in chap0.tex file :  \def\CallMintedCodeFromAnotherFile { \begin{minted}{c} int main() {     printf("hello, world");     return 0; } \end{minted} }   This one does work in the same file and same pc, any idea ?  \documentclass{uoyths} \usepackage{minted} \begin{document} \input{chap0.tex}   %Content      \begin{mainMatterEnv} \begin{minted}{c} int main() {     printf("hello, world");     return 0; } \end{minted}                 \end{mainMatterEnv} \end{document}   Error message is :    I found the solution and post it to my blog as well.  The solution is : I have put the piece of code to  hello.cpp instead of directly inside \def and then I read it from this source file inside \def. It works perfectly:  \def\CallMintedCodeFromAnotherFile { \inputminted{c++}{hello.cpp} }

I'm trying to compile the following minimal example:  \documentclass{memoir}  % Enable subfloats within figures \newsubfloat{figure}  \usepackage{minted}  \begin{document} \begin{figure} \subbottom{% \begin{minted}{c} test; \end{minted} } \end{figure} \end{document}   but I get an error:  ! Argument of \FV@BeginScanning has an extra }. <inserted text>                  \par  l.13 \end{minted}}   I've tried replacing the minted environment with a inputminted which reads the code from a file, but to no avail.  How do I fix this?


Prove that: $\sec^2 20^\circ +\sec^2 40^\circ +\sec^2 80^\circ = \textrm 36$  My Attempt:  $$L.H.S=\sec^2 20^\circ + \sec^2 40^\circ +\sec^2 80^\circ$$ $$=\dfrac {1}{\cos^2 20°} +\dfrac {1}{\cos^2 40°} +\dfrac {1}{\cos^2 80°}$$ $$=\dfrac {\cos^2 40°.\cos^2 80°+\cos^2 20°.\cos^2 80°+\cos^2 20°.\cos^2 40°}{\cos^2 20°.\cos^2 40°.\cos^2 80°}$$.  I got paused here. Please help to prove this..

Evaluate $\tan^{2}(20^{\circ}) + \tan^{2}(40^{\circ}) + \tan^{2}(80^{\circ})$.  Can anyone help me with this? Thank You!


Find the sum of the following infinite series   $$\frac {1}{3!} + \frac {4}{4!} + \frac {9}{5!} + \ldots$$  I was trying this question ,but I couldn't get it. This is homework that my teacher has given me.  I solved this question using d'Alembert's ratio test but I didn't get a finite value.  If anyone could help me, that would be much appreciated. Thank you

Problem is to find sum  $$\frac{1}{3!}+\frac{4}{4!}+\frac{9}{5!}\cdots$$  What I knew doesn't apply on this problem  Some series are telescoping, some types are solvable using binomial , both look useless here Binomial gives  $$n (n-1) (n-2)x^3=1$$  $$n (n-1)( n-2)(n-3)x^4=4$$  What approach to use here?


This morning suddenly after hours of work I found my self unable to access admin account, just a blank page without any info. The anonymous and authenticated users  are logged in normally without any problem , like usual..    The first reflex was to clear all the cache manually from the database,but this drove me to this issue:    Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[HY000]: General error: 2006 MySQL server has gone away' in /home/www/includes/database/database.inc:2171 Stack trace:  #0 /home/www/includes/database/database.inc(2171): PDOStatement->execute(Array)  #1 /home/www/includes/database/database.inc(683): DatabaseStatementBase->execute(Array, Array)  #2 /home/www/includes/database/database.inc(2350): DatabaseConnection->query('SELECT expire, ...', Array, Array) #3 /home/www/includes/lock.inc(167): db_query('SELECT expire, ...', Array)  #4 /home/www/includes/lock.inc(146): lock_may_be_available('schema:runtime:...')  #5 /home/www/includes/bootstrap.inc(433): lock_acquire('schema:runtime:...')  #6 /home/www/includes/bootstrap.inc(455): DrupalCacheArray->set(Array)  #7 [internal function]: DrupalCacheArray->__destruct()  #8 {main} thrown in /home/www/includes/database/database.inc on line 2171   I tried to change the theme by removing it from the themes folder but nothing worked. Any Help please..

Recently I started getting an error every time I try and add a content no matter what type.  This is the error that shows up in the browser:     Additional uncaught exception thrown while handling exception.        Original   PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT COUNT(cid) FROM {comment} WHERE status = :status; Array ( [:status] => 0 ) in comment_count_unpublished() (line 313 of /Applications/MAMP/htdocs/modules/comment/comment.module).        Additional      PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: INSERT INTO {watchdog} (uid, type, message, variables, severity, link, location, referer, hostname, timestamp) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6, :db_insert_placeholder_7, :db_insert_placeholder_8, :db_insert_placeholder_9); Array ( [:db_insert_placeholder_0] => 1 [:db_insert_placeholder_1] => php [:db_insert_placeholder_2] => %type: !message in %function (line %line of %file). [:db_insert_placeholder_3] => a:6:{s:5:"%type";s:12:"PDOException";s:8:"!message";s:154:"SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT COUNT(cid) FROM {comment} WHERE status = :status; Array ( [:status] =&gt; 0 ) ";s:9:"%function";s:27:"comment_count_unpublished()";s:5:"%file";s:56:"/Applications/MAMP/htdocs/modules/comment/comment.module";s:5:"%line";i:313;s:14:"severity_level";i:3;} [:db_insert_placeholder_4] => 3 [:db_insert_placeholder_5] => [:db_insert_placeholder_6] => ; [:db_insert_placeholder_7] =>  [:db_insert_placeholder_8] => 127.0.0.1 [:db_insert_placeholder_9] => 1338336955 ) in dblog_watchdog() (line 154 of /Applications/MAMP/htdocs/modules/dblog/dblog.module).   I also get the following error in my php error file:     PHP Fatal error:  Uncaught exception 'PDOException' with message 'SQLSTATE[HY000]: General error: 2006 MySQL server has gone away' in /Applications/MAMP/htdocs/includes/database/database.inc:2136        Stack trace:   0 /Applications/MAMP/htdocs/includes/database/database.inc(2136): PDOStatement->execute(Array)   1 /Applications/MAMP/htdocs/includes/database/database.inc(664): DatabaseStatementBase->execute(Array, Array)   2 /Applications/MAMP/htdocs/includes/database/database.inc(2315): DatabaseConnection->query('SELECT expire, ...', Array, Array)   3 /Applications/MAMP/htdocs/includes/lock.inc(167): db_query('SELECT expire, ...', Array)   4 /Applications/MAMP/htdocs/includes/lock.inc(146): lock_may_be_available('theme_registry:...')   5 /Applications/MAMP/htdocs/includes/theme.inc(447): lock_acquire('theme_registry:...')   6 /Applications/MAMP/htdocs/includes/bootstrap.inc(427): ThemeRegistry->set(Array)   7 [internal function]: DrupalCacheArray->__destruct()   8 {main}         thrown in /Applications/MAMP/htdocs/includes/database/database.inc on line 2136   I am having a little trouble deciphering these error messages. Could anyone help me understand what's going on here?


Given V   t-> W   s-> U:  if S and T are both one-to-one, show that ST is one-to-one.  I know that (S.T)(x)=(S.T)(y) for some x,y∈Rn. But I don't know how to apply it here. I'm lost

For injective side, in my opinion, we can find two square matrices $A, B$ with each injective but $AB$ has a zero row ($\dim\ker(AB)\ne 0$), so $TS$ is not injective. But I don't know how to find such matrices.  For surjective side, I have no idea how to start.  I feel my idea is very confusing, could someone give me a clear way to solve the problem?


My question: is there any way that wa can generate a word output file from latex ?  Input : latex file output: word file instead of pdf  Thank you in advance

I often have to write up reports based on the analysis of some data. I use R to analyse the data and export tables, figures, and text. This is then included into a LaTeX document either using input or Sweave ().  However, when I collaborate with others, I sometimes need to provide a document in Open Office / MS Word format.  Question:  Thus, assume the simplest scenario   I have a LaTeX document with text, tables, and figures I need to export this reliably into Open Office or MS Word format: this includes mathematical formulas, table formatting, and quality figures) I don't need to go back from MS Word to LaTeX   What is a reliable, efficient, and preferably free process?  Initial Thoughts:   Export to HTML,  LaTeX - LyX - ODF Use odfWeave  that deals with some specific issues associated with LaTeX to Open Office conversion    I was hoping that there is an expert out there who has worked out a good system already.


I was talking with a friend of mine when she told me that "pretty sure" means something like "more or less sure". I've always known that it meant "totally sure" and was astonished to find this out.  Thinking about it, I could not remember why or how I learned the wrong meaning and looking on the Internet I found more people that thought the same before being corrected.  Edit: I do know that there is a question answering the meaning of the expression. What I'm trying to find out with this one is the reason why some people like me learned the wrong meaning and was sure it was correct. Sorry if I wasn't clear enough.   What could be the origin of such misunderstanding?

Does that expression mean "I'm totally sure" or "I'm almost sure"? I always thought the first option was correct, but once I saw in a series episode a character who said that, and his interlocutor expressed skepticism about it (something like "Are you sure or pretty sure?"). Does that depend on context, or does it always mean the same?


I know that OEM licenses cannot be transfered to new Windows installations, but in this case I am moving existing Windows 10 installation with the SSD to a new setup. My Microsoft-account is tied to the digital license. From the perspective of the SSD / W10 install, it would be the same installation with major hardware changes, right? If I need to re-activate Windows after moving the SSD, can I still do this thing?: Troubleshoot => I recently changed hardware on this device => This is the device that I'm using at the moment I say it again: I am not trying to re-activate inside a new installation, but the old installation that is on the SSD from the old PC setup.  EDIT: The question here  is similar but the OP tried to activate new install, instead of old install. Also the OP or others in that question never mention trying the phone activation so could that be a 50/50 solution? OP said that he tried to change the license key and got an error, but did he get the option to call phone activation? It should appear if there is a problem with the license key.

I'm trying to activate a new Windows installation using the digital license that's associated with my Microsoft account. On the old (activated) pc, I can go to the activation setting and see the "Windows is activated with a digital license tied to your Microsoft account" message.  On the new PC, if I log in with the same Microsoft account, Windows is not activated. I get the message that a valid product key has not been found (0xC004F213).  Using the trouble shooter, I get the message that Windows cannot be activated on this device. I then click "I recently changed the hardware for this device."  I then get a dialog showing me the device with the old motherboard. If I click "Activate", I get a simple "Windows cannot be activated" message.  If I go back to settings and try to change the product key, and enter the old pc's product key, I get an error that says the key is invalid (0x80041023).  I'm kind of at a loss now. How do I get this working?  Windows 10 Pro x64 was installed on both devices using the same USB drive.


I am new to cycling. I recently got Jamis Trail X with 27.5x2.25" tires. This is a bit hard (not easier) on city roads. I was thinking about replacing the tires with max 1.5" wide hybrid or road tires. I researched a little bit and learned that 27.5 is not actually 27.5 rim. It's 26.5" or 584mm in diameter. My question is, can I replace these tires with any 584 or 650b tires?

We often get questions on bicycles.stackexchange about fitting wider or narrower tires to bicycles. We have a large number of these with answers suiting the specific bike or style of bicycle in question, but I have been unable to find one that provides a generic answer covering off all things that need to be considered. For most bicycles, the answer is the same regardless of the specific style and sizes of tires in question.   This is intended as a canonical question that we can point closed questions to.


Is it possible to have a tabs panel in Fullscreen Mode in Google Chrome?  I know the option of using Ctrl + Tab / Pg Up / Pg Dn commands.   I would prefer Google-created solutions, for compatibility and safety.

Firefox can do it, can Chrome?   Here's what I'm looking for:


I'm running a Toshiba Qosmio V1.32002.   I have had a dual-booted Win8/Ubuntu 13.10 traditionally, and I recently upgraded to 14.04.  When I start my computer, the grub bootloader doesn't even pop up and goes straight to starting up Win8. Any idea as to how I could go about bringing my Ubuntu back from the dead here?

On my old laptop (legacy BIOS, MBR disk), this was perfectly possible to get working:  I turn on the computer and see the Windows Boot Manager  I use EasyBCD (or BootPart, or something else) to add an option to the BCD menu which allows me to boot into GRUB, and then into Ubuntu   I can't figure how to do this on my new laptop (UEFI, GPT disk), whether in UEFI or legacy mode. Currently I've installed (and even booted!) Ubuntu on my laptop, but only with the help of an external GRUB (on a USB flash drive). How can I add GRUB as an option in the Windows Boot Manager on a UEFI laptop? (No, I don't want to change my primary boot loader. So no, I don't want to overwrite the Windows boot loader with GRUB.)


Currently , I am running ubuntu 15.10 on my Dell laptop (ram-4GB) . I want to install ubuntu 16.04 LTS on my laptop as ubuntu 15.10 is no more supported. I don't want to lose my data while changing os , can I install 16.04 without losing data .   Thanx for helping in advance

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


Many times I've tried to find a community to ask a question in, but it's somewhat difficult to wade through the page of 'squarish' buttons for the community entry points. Is there some place or some way to get a text list of them (to make it easier to search)? Or am I missing it somewhere?

Where can I find a list of all the Stack Exchange sites?  I need to ask a question about cars (where my total knowledge is about zero) but I can't find a cars Stack Exchange site - tried guessing all the obvious (and pun based) names.  I assume the list of a dozen or so at the bottom of this page is only a subset? There must be a site on a topic as geeky as cars!  A list of future/beta sites would also be useful - I found a few on topics I'm interested in only after they had been up for a while.


My OS is Ubuntu 16.04 64 bit. In the same system I had also installed VirtualBox for Windows 7. It was alright since last several months. Today there was an OS update through Software Updater. During installation it was observed that VirtualBox update couldn't be installed. However, after reboot, when I went for launch of VirtualBox, Windows couldn't start, rather total system was hanged. Need solutions to overcome the problem.

Ubuntu 16.04 LTS Virtualbox 5.0.40 ubuntu r 115130  Today after upgrading to kernel 4.13.0-26 guest vbox machines started to crash whole ubuntu. just hard poweroff is working.  If I startup with kernel 4.10.0-42 everything works fine.  what may be the problem ?


I have installed both Windows 7 and Ubuntu. But today when I turned on my PC it showed an error regarding GRUB RESCUE. So I solved it referring to a site. The site told the following steps:     If you have Windows 7:         Insert your Windows install disc   Press any key at the “Press any key to boot from CD or DVD” message    to boot from the disc Choose Repair your computer after you select   the language, time and keyboard method (for Windows 7 users)   Select your Windows installation drive (usually C:)   Click Next   Select Command Prompt in the System Recovery Options window   Write the following commands in the Command Prompt:  bootrec /fixmbr bootrec /fixboot bootrec /rebuildbcd       Press Enter after each command      After doing this steps my Windows 7 started loading without any problem, but I cant boot with Ubuntu now. Please help me with your valuable suggestions.

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


After an English class on the subjunctives, I am now confused about the usage of "would".  The definition provided for "would":     (expressing the conditional mood) indicating the consequence of an imagined event or situation.   Before the class, I would typically say something like "I'm sure that would happen."  But come to think about it now, how could you be sure if the consequence is imaginary?  My questions are, instead of saying "that would happen" in the sentence, should I use "that will happen"? And is the original sentence grammatical?  Edit: I'm not asking about the general usage of "will" and "would". I guess my question is more about the combination of word "sure" and "would" since the definition confused me in the first place. So I really don't think my question is a duplicate.

Here is the sentence from the test     Without the Sun there _____________ no light, no heat, no energy of any kind.   a) will be   b) would be   c) will   The answer is obviously "b" because it is second conditional. However in another sentence     Oxygen is an element of greatest importance to the Earth as all living things __________ without it.   a) would die   b) will die   c) will be dying   the correct answer is "b" and not "a". I don't understand why, because both sentences are constructed similarly, even the "without" preposition appears in both of them.


I have an old laptop (Lenovo e530), which came witn Windows 7 preinstalled. My new laptop arrived with Windows 10 preinstalled (Lenovo e550). I would like to put Windows 7 on my new laptop, too. Can I somehow "move" the Win 7 licence from an old laptop to an new one? Or do I already have a right to install all previous versions of Windows, once I have Windows 10 on it?  None of laptops has any stickers with serial numbers.

We get a lot of questions on Super User about Windows activation and licensing. This question is an attempt to answer the most common questions in one place with a .   When reinstalling Windows, the following questions often come up:   Can I transfer the copy of Windows from my old computer to a new one? Does the license key on the sticker on my computer work on any computer? If I have a 32-bit version, can I install a 64-bit version? I have an OEM version of Windows, but only a retail disk. Can I still use it? I want to install Windows with a different language. Do I need a new license in that language? I changed some hardware. Will I be able to reactivate my computer? Can I back up my activation before doing a reinstall? How many computers can I install my license on? Do I have to deactivate my old installation before transferring a license? If so, how? How does licensing work in Windows ? What are the restrictions on transferring, reinstalling, and changing versions of Windows?


Two cowboys $A$ and $B$ decide to solve a dispute with a duel. Cowboy $A$ hits his target $\frac13$ of the time. Cowboy $B$ hits the target $\frac23$ of the time.  It is decided that $A$ will take the first shot, cowboy $B$ will take the second shot (if still alive). This will continue until there is only one left alive. Also, a cowboy can not shoot two times in a row. What are cowboy $A$ chances of winning the duel? My logic is to simulate the cases where $A$ wins: I Case:  $A$ wins: $\frac13$ II Case: $A$ loses, $B$ loses, $A$ wins: $\frac23\cdot\frac13\cdot\frac13$ ... But I don't know what to do from here. Any help?

Two players A and B shoot a target alternately, until somebody hits it and wins the game. Player A takes the first shot. Each time they take a shot, their probabilities of hitting the target are $p$ and $q$ respectively. Which is the probability $\mathbb{P}$ that A wins?   Is the following solution correct ?  A wins if :  he wins with the $1$st shot or  they both fail to hit it during the first $2$ shots, and A hits it with the $3$rd shot or  they both fail to hit it during the first $4$ shots, and A hits it with the $5$rd shot or  ...  So,  $$ \mathbb{P} = p + (1-p)(1-q)p + (1-p)^2(1-q)^{2}p + ... =  p\sum_{n=0}^{\infty}[(1-p)(1-q)]^n = \cfrac{p}{p+q-pq} $$  Thank you in advance


Dears,   I have applied for UK visitor visa, this is my second attempt. my first one was refused. HO sent me the refusal letter in an email and I received my passport later. But this time they sent me an email stating the visa application has been concluded and has been sent back to the Visa Application centre. Does this mean I have got the visa, or do they ever send the refusal letter with the passport?  I need this because I have to take the tickets as I have to travel on December 21st if I get the visa. your help is highly appreciated.  I applied in Germany.  Thanks!

I got two mails from the UK embassy in Abu, saying your visa application has been concluded. I'm really confused, did I get the visa or not? What could the possible results be?


I am looking for a general formula for the sum of columns on Pascal's triangle (finite terms), i.e. $$\sum_{k=0}^{k=n} {k+d \choose k}$$

I have observed the following relation  $$\binom{n}{k}=\sum\limits_{i=0}^{k} \binom{n-i-1}{k-i}, \quad \frac{n}2\leq k \leq n-1$$  Numerical example with $n=5$ and $k=3$  $$\binom{\color{red}5}{\color{blueviolet}3}= \binom{\color{Magenta}4}{\color{blueviolet}3}+\binom{\color{blueviolet}3}{\color{Orange}2}+\binom{\color{Orange}2}{\color{YellowGreen}1}+\binom{\color{YellowGreen}1}{\color{Brown}0}$$  $$10\  \ \  = \  \ \ 4 \ \  \ +\ \  \ 3 \ \  \ +  \  \ \  2  \  \  \ \ + \ \ 1$$  Is this relation true? If yes, is there a name for it?  I´ve used identities like $\binom{n+1}{k+1} = \binom nk + \binom n{k+1}$ to show the relation above, but I failed. Does anyone have an idea how to manage it?  Thanks for taking time to read the question.


Two days ago I updated my system. One of the updates was the nvidia driver.  While updating it asked me if I wanted to update some config file as well. It told me the recommended thing to do was to update this config file. Usually I never do so, but I did agree to upgrade those config files.  Today I started my PC and was greeted with this message:       After that I got a message box with the following options:     What information would you like to review?   ⠀   □ Review the xserver log file   □ Review the startup errors   □ Edit configuration file     I tried to run it in low graphics mode, but there was no result. Then I tried to reinstall nvidia 331 drivers, but I had the same problem, nothing changed.   So does anyone know what can be done here?

Note: This is an attempt to create a canonical question that covers all instances of "low-graphics mode" error that occurs to a user, including but not limited to installation of wrong drivers, incorrect or invalid lightdm greeters, low disk space, incorrect installation of graphics card like ATI and Nvidia, incorrect configuration of xorg.conf file while setting up multiple monitors among others. If you are experiencing the "low-graphics mode" error when trying to login but none of the following answers work for you, please do ask a new question and then update the answers of this canonical question as and when your new question gets answered.   When I try to boot into my computer, I am getting this error:  The system is running in low-graphics mode Your screen, graphics cards, and input device settings could not be detected correctly. You will need to configure these yourself.   How do I fix the failsafe X mode and login into my computer?  Answer index:


I think [ ! -f $2 ] means   $2 file doesn't exist.  is it correct?  I'm pretty sure [ ! -f ] means file doesn't exist. but I'm not sure for $2.  give me some help.

I've found some special parameter with Bash starting with $ sign. Example: When I was wandering for exit status I knew about $?, process ID  $$ etc. So, I am sharing  this post to know which are special bash (shell) parameters and their usage.


Having trouble playing DVDs on my laptop. They are .vob files. Neither VLC, Mplayer nor SMPlayer seem to help. Anything else I could do?

I just downloaded a DVD which is for a movie. After uncompressing the DVD file I see .VOB, .IFO and .BUP files. If I open the first .VOB file it shows me the DVD menu but I can't interact with it. So, my question is... is Totem able to play those kind of files? If so, how can I achieve that? What other app could I use in order to reproduce those files?  Edit  Using VLC didn't work neither. I forgot to mention I have already tried that. Let me rephrase: if I open the first video file it shows the DVD menu, BUT I can't interact with it.


I like to download online streaming videos off Chromium. Firefox can do this, but Chromium can't. Any help?

What are instructions on how to download videos from YouTube?    Notice: Terms of Service Violation  Please be aware that by following any of the answers below, you will be violating YouTube's . In particular, from Section 5.B.:     Content is provided to you AS IS. You may access Content for your information and personal use solely as intended through the provided functionality of the Service and as permitted under these Terms of Service. You shall not download any Content unless you see a “download” or similar link displayed by YouTube on the Service for that Content. You shall not copy, reproduce, distribute, transmit, broadcast, display, sell, license, or otherwise exploit any Content for any other purposes without the prior written consent of YouTube or the respective licensors of the Content. YouTube and its licensors reserve all rights not expressly granted in and to the Service and the Content.


How can I get the largest key in a dictionary which may have mixed data types? For example:  myDict = {1: 'foo', 2: 'bar', 3: None, 4: 1000}  I want to get the largest key which is 4.  I tried max(myDict) which does work, but is this always reliable?  Or should I use max(myDict.keys()) instead?

I have a dictionary: keys are strings, values are integers.  Example:   stats = {'a':1000, 'b':3000, 'c': 100}   I'd like to get 'b' as an answer, since it's the key with a higher value.  I did the following, using an intermediate list with reversed key-value tuples:  inverse = [(value, key) for key, value in stats.items()] print max(inverse)[1]   Is that one the better (or even more elegant) approach?


I am currently using Ubuntu 20.04 beta and I get this error on sudo apt update  E: The repository 'http://ppa.launchpad.net/webupd8team/java/ubuntu focal Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.

When updating, I get the following error message:   W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file.   Here, I find another statement on this error:   This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need.    Is this what I should do?


Does anyone remember the name of a story (I think it was a novella from the 1960's or 70's) about the last man left alive on earth after a nuclear war, who is taken care of by a group of robots who gradually evolve into a sentient species?

I read this story in a sci-fi anthology in the mid 90s, but I remember thinking the book looked pretty old by then.  The story is about a man who wakes up from stasis / cryogenic sleep in the future, only to discover that he's the only human left alive on Earth. He's greeted by a simple robot which is programmed to follow his instructions. He spends some time in the library, but eventually decides to go back to stasis. Before he does, he gives the robot an order, which it interprets to mean that it should expand its own capabilities.  When the man wakes up again next time, many years have passed, possibly centuries, and the robot is noticeably smarter, having gained several extensions and upgrades. For some reason, the man goes back to stasis.  That keeps happening a few times, the man goes in and out of stasis, and every time he wakes up the robot has upgraded itself. Eventually the man gets so depressed about being the only human left that he decides to go back to stasis permanently.  The next time he wakes up, billions of years have passed and Earth is about to end. The robot, who by now is on the far side of the singularity, ushers him into a spaceship and puts him back to sleep.  The man wakes up a final time,       on a planet full of humans. The robot has spent the time when he was in stasis to find a new planet, terraform it, and create human beings to populate it. The twist is that everyone has a green tint, because they were modeled on a discolored picture of the man's wife, that he had in his wallet. The man decides he's fine with this.   I can't remember exactly why all the other humans were dead, could have been a war or a plague or something similar. I also can't remember why he went in and out of stasis, it could have been that he gave the robot a project to complete that would take a long time, and only woke up to check on its project.


My attempts at trying to create a new user on Ubuntu 15.04 desktop have been unsuccessful. Sure, I get the new user and the login works and all seems fine. But then I can't use anything requiring sudo. The new user doesn't seem to be in the "sudo group". How can I create a truly new user with full administration rights (install, update, etc.) ?

In /etc/sudoers I see this:  # Allow members of group sudo to execute any command after they have # provided their password # (Note that later entries override this, so you might need to move # it further down) %sudo ALL=(ALL) ALL   So how do I add a user to that sudo group?


I find the lack of information on the internet about the third derivative astounding.  When the first derivative of a function touches or crosses the x-axis, it is a critical point and possibly an extrema. If $f'(x)\gt0$, the slope of $f$ is increasing; if $f'(x)<0$, the slope of $f$ is decreasing.  When the second derivative of a function crosses the x-axis there is an inflection point, and the concavity reverses. If $f''(x)>0$, $f$ is concave up; if $f''(x)<0$, $f$ is concave down.  What visual effects does the third derivative have on its function? Do higher order derivatives have any clearly visible effects?

(Originally  by AJAY.)  What is the geometric, physical, or other meaning of the third derivative of a function at a point?  If you have interesting things to say about the meaning of the first and second derivatives, please do so.


In the given sentence,"There’s Mr. Som, who they say is the best singer in the country" is "who" is the correct word to be used or "whom"

I can never figure out whether I should use who and whom. Most people use who for both colloquially, but some people say this is not correct.  What’s the rule for using who and whom correctly?


The school where I work has an S when it is an acronym (NEGS) it looks odd with an apostrophe to show ownership e.g. NEGS' tennis team...any thoughts?

I work with a company whose name is frequently reduced to an initialism (acronym).  Let's say the name is "Cool Computer Systems" (CCS).  I am engaged in an ongoing, bloody battle with the marketing department, wherein they insist the following apostrophe use is correct:  Buy CCS' New Product.  Reading that line brings visions of crying 4th grade teachers and librarians to mind.  I am quite certain that it should be written:  Buy CCS's New Product.   UPDATE: The examples are in title case because the sentence is the subject line of an e-mail.  UPDATE: Their argument is that "Systems" is plural.  I say that plurality doesn't matter, because "Systems" is part of the name.  The name as a whole should be handled as a singular entity, because the company is, in fact, a single, legal entity.  Thus, the possessive form should be written:  The Emperor's clothes Cool Computer Systems's clothes CSS's clothes


For example, can I make Space + J act as Ctrl + J, and Space act as Space when pressed on its own?

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.


Can I install Ubuntu 14.04 having these   Memory       1GB Processor    AMD sempron Processor 3000+ Graphics     Gallium 0.4 on NV4C OS Type      32 bit  HDD          500GB

I'm thinking about installing Ubuntu Desktop, but I don't know what flavor is the best for my system. What are the minimum and recommended hardware requirements? What kind of CPU? How much memory? Should I have Hardware Acceleration? What flavor should I use?  This is an attempt of a canonical answer. My answers have the "official  requirements", the recommended are a mix of official sources and opinion based (along with the answer it's told the source). You can comment or edit if you feel that the information is obsolete or incomplete. It is a good rule of thumb that any system capable of running Windows Vista, 7, 8, x86 (Intel) OS X will almost always be a lot faster with any Ubuntu flavor even if they are lower-spec than described below.


I have a raster with one band and I would like to query a set of overlying points (.shp) to determine how many points as well as which points points fall under a range of certain pixel values associated with the raster.  This is straightforward in ArcGIS but I want to use GDAL/OGR/Python to automate this process.   I can think of a few ways to potentially accomplish this: (1) Join the raster values to the points, add a new field with the raster values and then query the resulting new_points.shp file.  (2) Write an effective SQL statement that queries the points and the raster to write out a new file with only those points that correspond to the value range I'm interested in. Potentially using a VRT file (3) Convert the raster to a shapefile using gdal_polygonize (very time intensive!) and then use an SQL statement along the lines of SELECT COUNT(*) FROM points, new_poly WHERE ST_INTERSECTS(new_poly.geometry,points.geometry) -dialect SQLITE input.vrt again using a vrt table.   Number (2) seems like the best and most efficient option, but I am unfamiliar with querying both raster and vector data simultaneously. Is there a standard or accepted way to do this?  EDIT: Another option seems to be the gdallocationinfo utility, but it seems that you can only pass lat/long coordinates and not shapefiles.

I am working on a computational model of the abundance of wild pollinators across a landscape.  The model itself is complete, and I am now struggling with a post-processing step.  I have my GDAL pollinator supply raster that looks something like this (lighter colors mean higher pollinator visitation to a pixel):    And I have an OGR shapefile of points representing sample locations on the landscape:    I'm trying to run some analysis on the pixels under these points, but to do so, I need to be able to extract the value of a pixel under a point.  Is it possible to extract the value of a pixel under a point using only OGR and GDAL through Python?  I would prefer to avoid reading the entire raster into memory through ReadAsArray(), as my output rasters are very, very large (too large to fit into memory).  I noticed , which is similar, but requires a command-line call.


I am new to php. I just got to know about sql injection, and have been thinking of ways to avoid it. One way I could think of is this: If we could hash the username, the password and other details before querying, then we can avoid sql injection completely. So is there a good way to do this? I mean, can we use a hash function to prevent sql injection?   The languages I am familiar with are C and C++. Is there a way to obtain the hex coding of each character entered in the string so that it can be converted to some other type before querying?

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?


If for example we have 2 people one moving in speed v relative to the other, according to special relativity the time passing for the moving person is slower than for the stationary person. However from the moving person’s prospective he is stationary and his friend is moving so time should move faster for him. What’s going on?

Suppose we have two twins travelling away from each other, each twin moving at some speed $v$:    Twin $A$ observes twin $B$’s time to be dilated so his clock runs faster than twin $B$’s clock. But twin $B$ observes twin $A$’s time to be dilated so his clock runs faster than twin $A$’s clock. Each twin thinks their clock is running faster. How can this be? Isn’t this a paradox?


I have a script in python. Here is some of my code:  from splinter import Browser url = "http://arashiyan.ir/Narm/entekhab.html" browser=Browser('firefox') browser.visit(url) second_found = browser.find_by_name("LsnGrp[]")[3] second_found.fill("3")   I want to run this script in one part of my android application.I researched and find some frameworks like kivy but it will make complete app with python. does it possible with jython? Tnx

We are working on an  version and this platform has a nice Python API..  However, there is nothing official about Python on Android, but since  exists, is there a way to let the snake and the robot work together??


Cormac McCarthy has several idiosyncracies in his writing style, but I'm looking for the name of a specific style he employs: When he joins together several actions or clauses with "and".  Example that I just made up: "He walked over to the horse and whispered to it and stroked it and let it know that everything was ok and closed his eyes and…"  I'm fairly certain it has a name, but it escapes me, and it's hard to google the word "and".

I was always under the impression I should not use and more than once. I have this text:     I appreciate that all my previous work experience is within office based industries however I am a quick learner, keen and enthusiastic and am looking to change to ensure longevity of career and that the remainder of my working life is spent doing something that I enjoy and that I can feel passionate about.   Are there too many ands in that sentence?


In C language, you cannot declare any variables inside 'case' statements.  switch ( i ){ case 1:   int a = 1; //error!   break; }   However, you can when you use with curly parentheses.  switch ( i ){ case 1:   {// create another scope.     int a = 1; //this is OK.   }   break; }   In Javascript case, can I use var directly inside case statements?  switch ( i ){ case 1:   var a = 1   break }   It seems that there is no error but I'm not confident this is grammatically OK.

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


Since some weeks ssh asks me to Enter passphrase for key '[home directory]/.ssh/id_rsa' without any changes to the system. I may have installed updates, but I can't make a connection to a specific one, also not after going through /var/log/apt/history.log.  Invoking gpg-agent which I recall is somehow related to storing such passwords prints gpg-agent[24068]: no gpg-agent running in this session to terminal.  I'm using Unity and see the same issue when using GNOME shell.  After removing a stale ~/.gnupg/gnupg_spawn_agent_sentinel.lock I could fix and issue where I experienced a ~60 seconds freeze of the screen between login and displaying of the desktop for both Unity and GNOME shell and after every login as well as blocking of email sending in thunderbird because the add-on Enigmail was launching /usr/bin/gpg2 --charset utf-8 --display-charset utf-8 --use-agent --batch --no-tty --status-fd 2 --with-fingerprint --fixed-list-mode --with-colons --list-secret-keys which (run in a terminal) permanently printed gpg: waiting for lock (held by 28158) .... So, there might be more issues regarding stale locks.  I'm using Ubuntu 17.10.

Since I updated to Ubuntu 17.10 a while ago, my private keys – the which I use for example to access my server via ssh – are not unlocked programmatically after login anymore.    My understanding is, that usually the seahorse client should take care of this, by asking you whether or not to store the key's password when typing them in for the first time.  My first guess was, that seahorse-daemon wasn't running for some reason, but it is:  user@Zeus:~$ ps aux | grep seahorse user    19170  0.0  0.1 432636 26564 ?        Ss   00:07   0:00 seahorse-daemon   My second guess was, that for some reason I have to delete all related passwords stored in seahorse under »Passwords->login«:    I was hoping to force the client to ask me again and then storing them again. But this didn't help either. The client does not pop up to ask me...  Then I found this question, which could be related, but did not help me:    As the management of other passwords work as expected (for example passwords for nautilus, Chromium, Nextcloud etc.) I assume the problem has to do something with ssh-agent...  Can anybody hint me in the right directions, how to solve this problem? Has anything changed in the way how GNOME handles passwords? Maybe some new fancy program failed being installed during the upgrade process?   UPDATE When I add the private key to the authentication agent again with:  ssh-add ~/.ssh/id_rsa   and try to log in, I will be asked to unlock the key only once, after that the key gets unlocked programmatically. But this works only until the next reboot. After a fresh start, I have to add the key again...


In sage, I got a lot of bright blue colors that aren't readable. I want to change them, but I don't know colors' source or from where they are coming.  How can I change colors to my liking?  Below you can find 2 screenshot of my terminal opened on sage.   I did use setterm to change foreground text, but the problem is that it is still bright blue in color?

I can change the colour through preference , but how can I change the background colour and text colour of terminal through the command line?


Let $A$ and $B$ be sets. Suppose that $\#A<\#B$. That is, $B$ has strictly greater cardinality than $A$.     Is it necessarily true that $\#(2^A)<\#(2^B)$? In particular, is this question decidable in ZFC without the (generalized) continuum hypothesis?   , but this seems to be a different question (though I'm not 100% certain). It is also true (in ZFC) that $\#A<\#B$ implies $\#(2^A)\leq\#(2^B)$. The question is whether the “weak inequality” can be strengthened.

Is it generally true that if $|P(A)|=|P(B)|$ then $|A|=|B|$?  Why? Thanks.


Is there any difference between these sentences:   You must try it. You should try it.   With some respect, I mean when talking to elders.

I tend to use should when it's a suggestion I don't have a strong opinion on, i.e. it could be done in many other ways than the one I'm suggesting and it can still happen.     You should stop by that gas station to go to the bathroom.   On the other hand, I usually use must for things that have to happen in a certain way; any other way would make that thing not to happen. The problem is that some people find this usage harsh, as they receive it like if I'm giving them an order.      You must cross the street to get to that store.   To me, it's just a depiction of reality, not an order. But I'm neither a native speaker nor a regular person. :-)  So, what's the proper use for must and should? Does this use differ among the English dialects?


I saw a similar type of question in this forum but let me tell you my data point is far less than the data mentioned in that my data points are very less compared to other posts. I have only 20 data points. I need to do forecasting using that data in R. Can you please suggest some forecasting technique using such a small data? I tried to take 19 observation as training and 1 observation to validate & fitted an auto.arima model but while I'm trying to predict it for 1 time period ahead I'm getting prediction as null.

I have a question related to modeling short time-series. It is not a question , but how. What method would you recommend for modeling (very) short time-series (say of length $T \leq 20$)? By "best" I mean here the most robust one, that is the least prone to errors due the fact of limited numbers of observations. With short series single observations could influence the forecast, so the method should provide a cautious estimate of errors and possible variability connected to the forecast. I am generally interested in univariate time-series but it would be also interesting to know about other methods.


It has the form   $$ z \rightarrow w = \frac{a z +b}{cz +d } . $$  This is apparently not a linear function. A linear function should be in the form of   $$ w = a z +b ,$$  right?   ps: I am reading the book by Ahlfors.

Now I'm confused with what "a linear transformation" means.  In linear algebra textbook, I learned that a linear transformation is $T:V \to W$, where V,W are vector spaces, which satisfies additivity and homogeneity, in other words, $T(u+v)=Tu+Tv, T(av)=aTv$ for all $u,v \in V$ and $a \in F$  But in my complex analysis textbook, $\displaystyle f(z)=\frac{az+b}{cz+d}$, $a,b,c,d \in \mathbb C$, is introduced as an example of a linear transformation.   However, this function $f$ doesn't seem to follow the definition from linear algebra. Indeed, $f(0) \neq 0$.  Is it like there are two kinds of linear transformations in mathematics, or they are actually the same thing but I don't get it well?


Ok so we are going to begin looking at Set theory next week in class so I thought I would try to learn a bit about it before we start. I am curious and perplexed by $(A \cap \emptyset)′$ in regard to what it can be simplified to as when using the rules of set theory.   For example if I have $U$ and $A$, $B$ are both subsets does that mean that $(A \cap \emptyset)′ = U$ or does  $(A \cap \emptyset)′ = (A)'$?  If anyone can please provide some insight that would be much appreciated.

We have learned that for universal set $U$ and  for set $A$ belonging to $U$, $A^c=U-A$ but what about for the empty set?


I want to scan a research paper of pdf format  using linux shell command. If I want to print/display only the name of the authors and the title of the paper, is there any specific way to do that?

Normally, we can search a keyword in a list of pdf files using the following command:  for file in *pdf; do  pdftotext "$file" - | grep keyword done   Now, from the search result, If I want to find the title name along with the authors/writers of the file manually, without using pdfinfo command, what will I have to do?


How do I integrate $\displaystyle \int \frac{x^2}{(x^2+9)^2}\, dx$  ?   I tried doing using algebra and solving the question a bit. But it didn't become something that looks solvable.  How should I do this?

I'm trying  to calculate $\int \frac{x^2 }{(x^2+1)^2} dx$ by using the formula: $$ \int udv = uv -\int vdu $$  I supposed that $u=x$ s.t $du=dx$, and also that $dv=\frac{x}{(x^2+1)^2}dx$, but I couldn't calculate the last integral. what is the tick here?           the answer must be: $ \frac{1}{2}arctan\ x - \frac{x}{2(1+x^2)} $ + C


Why does this expression evaluate true?  SimpleRoundTo(93.599, -2) > 93.6   When I use the SimpleRoundTo like this  ShowMessage(FloatToStr(SimpleRoundTo(93.599, -2)));   it shows 93.6.

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


Suppose we have a random number generator, and we do not know anything about the generator, including the distribution of its outputs. We are allowed to use the generator some number of times to get draws and observe the sample.   Then, from the sample(s), we want to find a number M such that we can say something like  "z% of the (future) draws from this random number generator will be less then M." (future draws meaning not including the draws we used to make sample(s))  How would I go about doing this, and are there any resources to go to?  Thanks!

I'm working on a multi-armed bandit problem where we do not have any information about the reward distribution.   I have found many papers which guarantee regret bounds for a distribution with known bound, and for general distributions with support in [0,1].   I would like to find out if there is a way to perform well in an environment where the reward distribution does not have any guarantees about its support.  I'm trying to compute a nonparametric tolerance limit and using that number to scale the reward distribution so I can use the algorithm 2 specified on this paper (). Does anyone think this approach will work?  If not, can anyone point me to the right spot?  Thanks a bunch!


My son likes to watch a specific YouTube video in the car sometimes, and he always touches the screen and stops the video. Is there any way to prevent this while keeping the screen on?

I have Samsung Galaxy S5. Is there a way to lock the screen but keep YouTube videos playing?  For example, a particular browser app or add-on that would allow for the audio to continue playing while the screen is off.


I am trying to dynamically add,delete and update records into a table  but i am getting following error.  java.lang.NullPointerException in preparedStatment object  i have tried this  try {         String sql = "INSERT INTO " + LoginFrame.userName + "." + TableInfo.tableName + "(" + txtIdName.getText() + "," + txtName.getText() + ") VALUES(?,?)";         JOptionPane.showMessageDialog(null, sql);          pst = (OraclePreparedStatement)con.prepareStatement(sql);          pst.setInt(1, Integer.parseInt(txtIdValue.getText()));         pst.setString(2, txtValue.getText());         pst.executeUpdate();      } catch (Exception ex) {         JOptionPane.showMessageDialog(null, ex);         System.out.println(ex);     }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Here is my code, I just can't get the login div to sit vertically aligned.  Code:    main {  display:flex; } .loginForm {  margin: auto; }  footer {     position: absolute;     bottom: 0;     left: 0; } <html> <head> <meta charset="UTF-8"> <title>Untitled Document</title> <link href="includes/css/basic.css" rel="stylesheet" type="text/css"> <link href="includes/css/layout.css" rel="stylesheet" type="text/css"> </head>  <body>   <main>   <div class="loginForm">    Login   </div>  </main>  <footer>   Footer  </footer> </body> </html>     But it just doesn't work. Can anyone give me any advice?

I have a div with two images and an h1. All of them need to be vertically aligned within the div, next to each other. One of the images needs to be absolute positioned within the div. What is the CSS needed for this to work on all common browsers?

testing...


Suppose we have a semisimple complex Lie algebra $L$, with a Cartan subalgebra $H$.  Suppose that $L= L_1 \oplus\cdots\oplus L_k$ with each $L_i$ a simple ideal of $L$.  I want to show that $H_i=H \cap L_i$ is a Cartan subalgebra of $L_i$.  For this I would need to show $3$ things from the definition of a Cartan subalgebra:  (i) $H_i$ is abelian  (ii) every non-trivial $h_i \in H_i$ is semisimple  (iii) $H_i$ is maximal with respect to (i) and (ii)  I feel like the first property follows immediately from the fact that $H$ is abelian being a Cartan subalgebra of $L$ itself, and so as $H_i \subset H$ we have that $H_i$ is also abelian.  I am struggling to figure out what to do with the other two cases, for (ii) a direct approach seems like it wouldn't work since there is no specific Lie algebra we are working with so I have no basis to calculate ad$(h_i)$ for a general $h_i \in H_i$, but I cannot figure out what approach to take.  Any help would be appreciated thanks :)

Let $L$ be a semisimple complex Lie algebra and $H$ a Cartan subalgebra. Suppose that $L=L_{1}\oplus ...\oplus L_{k}$ with each $L_{i}$ a simple ideal of $L$. Show that for $1\leq i \leq k$, $H\cap L_{i}$ is a Cartan subalgebra of $L_{i}$.  I have had no thoughts on this problem and no idea how to solve it hence I cannot make an attempt. I have seriously severe difficulties.


I am trying to extract specific data from a text file and obtain the first and second line from that second line.  I appended the textfile into an arraylist and I'm trying to find the specific data's index and add +1 to find the values I want.  I then alter those values.   When I try to write the values back into the textfile I keep getting "Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException".   This is my code.  public class AppendsScore extends quiz{     public void AppendsScore() {          String filename = "Data_CS";          FileWriter fw = null;          try {          fw = new FileWriter(filename, true);     }          catch (IOException e1) {         // TODO Auto-generated catch block             e1.printStackTrace();     }         List<String> Score = new ArrayList<String>();         Integer CorrectAnswers = quiz_questions.CorrectAnswers;         {          try (BufferedReader br = new BufferedReader(new FileReader(filename))){             String line=br.readLine();             //System.out.printf(FName + SName);             while (line != null) {                 Score.add(line);                 line=br.readLine();                 System.out.print(Score);             }             int name = Score.indexOf(FName + " " + SName);             int correct = 1 + name;             int NoofQuestions = 2 + name;             Integer CorrectInt = Integer.parseInt(Score.get(correct));             CorrectInt = CorrectInt + CorrectAnswers;             String CorrectStr = Integer.toString(CorrectInt); //To String from Double             Integer NoQuestionsInt = Integer.parseInt(Score.get(NoofQuestions));             NoQuestionsInt = NoQuestionsInt + CorrectAnswers;             String NoQuestionsStr = Integer.toString(NoQuestionsInt);             Score.set(correct , CorrectStr );             Score.set(NoofQuestions , NoQuestionsStr );             for(String str: Score) {                   fw.write(str);                 }             fw.close();         }             catch (FileNotFoundException e) {                 // TODO Auto-generated catch block                 e.printStackTrace();             } catch (IOException e) {                 // TODO Auto-generated catch block                 e.printStackTrace();             }      }    }   }


My question is about "getting it". Does it mean to thank sb. for his attaining sth.? Or, does it mean to thank sb. for settling sth.？Or, to thank sb. for understanding eth.?

In my native language we have lots of ways (some of them very funny) of saying that you, or someone else didn't understand a joke right away. That is, he/she needed some time to figure it out.  I wonder if there's any idiomatic way of expressing that in English.


I'm working on a project which uses postgresql with glassfish. When I execute Statement PreparedStatement pstmt = conn.prepareStatement(sql) it give me  java.lang.NullPointerException. Here is my code:     String sql = "DELETE FROM blocklist WHERE ? >= time + ?;";          try(Connection conn = this.connect();              PreparedStatement pstmt = conn.prepareStatement(sql))     {         pstmt.setLong(1, System.currentTimeMillis());         pstmt.setLong(2, blocktime);         pstmt.executeUpdate();     }     catch(SQLException ex)     {         Logger.getLogger(RecordManager.class.getName()).log(Level.SEVERE, null, ex);     }  connect() function is here which is being called at Connection conn = this.connect();: private Connection connect() {     Connection con = null;     try     {         con = DriverManager.getConnection(Config.dburl, Config.dbusername, Config.dbpassword);     }     catch(SQLException ex)     {         Logger.getLogger(RecordManager.class.getName()).log(Level.SEVERE, null, ex);     }     return con; }  Here is exception log: Severe:   Exception in thread "AWT-EventQueue-0" Severe:   java.lang.NullPointerException     at urrsm.sng.RecordManager.unblockrun(RecordManager.java:91)     at urrsm.sng.WebScocketEnd$1.actionPerformed(WebScocketEnd.java:45)     at javax.swing.Timer.fireActionPerformed(Timer.java:313)     at javax.swing.Timer$DoPostEvent.run(Timer.java:245)     at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)     at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)     at java.awt.EventQueue.access$500(EventQueue.java:97)     at java.awt.EventQueue$3.run(EventQueue.java:709)     at java.awt.EventQueue$3.run(EventQueue.java:703)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)     at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)     at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)     at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)     at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)


I'm asked to show that if $X$ and $Y$ are independent exponential random variables with parameter , then  has a Beta distribution.  Up to know I had to find the new pdf or df when $Y$ was of the kind $Y=aB + c$ which I understand now. Here a hint is given to use "Law of total probability" which I've only seen in measure theory.   My guess would be to compute  using the fact that the df of exponential distribution is . I'm stuck at that step.

Been crushing my head with this exercise. I know how to get the distribution of a ratio of exponential variables and of the sum of them, but i can't piece everything together.  The exercise goes as this:  If X,Y are independent exponentially distributed with beta = 1 (parameter of the exponential distribution = 1) then what is the distribution of X/(X+Y)  Any ideas?  Thanks a lot.


Just a quick question (not too open ended).  Is the Yongnuo YN 50mm f/1.8 Lens for Canon EF compatible with the Rebel T2i (550D)? And if so, would you recommend the lens?  Thanks in advance for any help.

This is specific to Canon, but what is the difference between EF and EF-S lenses?


Is there any way of getting subsections of a map as in, you have a larger map area in which you want to take out 3 smaller areas (A, B and C), you reference them on the "main map"  Currently I have people drawing the A, B and C areas on paint but is there a more direct way of doing it?

i want to create 4-5 detailed maps, and then an overview map that has rectangles that markes the locations of the detailed maps. Best case would be if the rectangles were links to the detailed map.   I have managed to make the overview and the rectangles, and think I know how to make the detailed maps one by one. The rectangles are drawn manually on the overview map. All layers that I plan on using are in the same QGIS project.  The final product that I hope to create would be the overview map on the first page, followed by the detailed maps. The overview would have links to the detailed maps, click on the rectangles to open the right detailed map.  Is there a way to link the detailed maps to the overview in QGIS 2.8 print composer?  I'm still not sure if I'm doing something wrong, when I try to create the overview. I want it to show the extents of all of my detailed maps.   Is this possible?


In my MWE below, I sort my bibliography with the nyt option (name-year-title), cf. the   under 3.1.2.1 General. Then I also include sortcites = true, which according to the manual will "sort citations if multiple entry keys are passed to a citation command. If this option is enabled, citations are sorted according to the global sorting order of the bibliography."  Since the "global sorting order of the bibliography" in my case is name-year-title, I'd expect my citations to be sorted first by name, then by year, and finally by title. But as the MWE below demonstrates, my citations are simply printed in the order given in the cite command. I was expecting "Lennon" to appear before "McCartney" since l preceeds m, but this does not happen. I am either not understanding what sortcites is supposed to do, or I am setting the options incorrectly. What do I need to do to automatically sort my citations by name?  \documentclass{article} \usepackage[style = authoryear-comp, sorting = nyt, sortcites = true]{biblatex} \usepackage{filecontents} \begin{filecontents}{\jobname.bib} @book{mccartney1965,     author = "Paul McCartney",     title = "Yesterday",     year = "1965"} @book{lennon1967,     author = "John Lennon",     title = "Lucy in the sky with diamonds",     year = "1967"} \end{filecontents} \addbibresource{\jobname.bib} \begin{document} \cites{mccartney1965}{lennon1967} \printbibliography \end{document}

I am using biblatex for citations and bibliography. Now I often have lists of multiple citations, for which biblatex has the \cites command. Now I can get citations to automatically sort if I don't want page numbers, but I cannot get it right with page numbers.  What I want is all citation ordered chronological (oldest first). Is this possible, or must I just do this by hand?  Here is an example.  \documentclass[11pt,oneside]{memoir}  \usepackage[     style=authortitle,     useprefix=false,     maxnames=2,     firstinits=true,     sortcites=true,     uniquename=init,     abbreviate=true,     backend=biber,     sorting=ynt ]{biblatex}  \begin{filecontents}{jobname.bib} @book{tom1,   author = {Author, A.},   year = {2001},   title = {This book is from 2001},   shorttitle = {2001}, } @book{tom2,   author = {Author, A.},   year = {1999},   title = {This book is from 1999},   shorttitle = {1999}, } \end{filecontents}  \addbibresource{jobname.bib}   \begin{document} This one is corrent.\footnote{\Cites{tom1,tom2}.} This one is corrent.\footnote{\Cite{tom1,tom2}.}   This one is incorrent.\footnote{\Cites{tom1}{tom2}.} This one is incorrent.\footnote{\Cites[1]{tom1}[12]{tom2}.} \end{document}


I spend most of my time answering Google Maps questions, but don't quite get the point of having three tags for them:        Why should someone choose the  tag instead of ?  In other words, why do the -api-3 and -api-2 tags even exist?

There are three main tags covering Google Maps' JavaScript API:         concerns version 2 of the API, .   As such, I perceive  to refer to Version 3 of the API by default. May we please merge  into ?


I've always found it a bit peculiar that Apple's marketing refers to iPhone without an article. There is a question  which discusses why it feels more natural to use an article, but I'm wondering what the actual grammatical status of the word "iPhone" would be.       Buy iPhone at your favorite Apple Retail Store.   My initial impression after reading this would be to interpret "iPhone" as its own plural, like "deer".     Now iPhone is even bigger on productivity.   Now it can't be exactly like "deer", as you would expect to see "iPhone are", "the iPhone" or "an iPhone".  So looking at both examples together, my next thought would be that perhaps "iPhone" is a mass noun, like "data". Substituting "data" in either sentence seems acceptable.     ...we could have sold many more iPhones...   Now they've made "iPhone" plural. I'm not sure how you could fit "data" into this sentence other than the slightly odd "datums".     The new iPhones include iOS 8...   ...and now "iPhone" finally has an article. The only word I can think of that can go in all of these sentences now is "coffee", but I'm not sure this is actually the same. "Coffee" seems to have the odd property that "a coffee" is different from "coffee", "a coffee" always means "some coffee in a vessel", and "coffees" is always the plural of the "a coffee" form even if you omit the article (as in "Coffees are expensive.", which is distinct from "Coffee is expensive.").    (All quotes were taken from official Apple correspondence,  and .)  So what category does the noun "iPhone" fall under? Is it equivalent to "coffee"? (And if so, what exactly is going on with the different forms of "coffee"?)

Apple is somewhat notorious for omitting articles when talking about their products, and statements such as "People love iPhone" hit my ear a little strangely. But when I stopped to think about it, I realized that I wouldn't say "the Windows" or "the iWork".   I couldn't come up with a reason that I use the definite article before some product names and not others. Is there some sort of convention (probably not a hard-and-fast rule) for usage here?


I am trying to obtain an output such as      Theorem 4 (see [1, Theorem 12]). Statement of the theorem.   Separately, the commands \begin{Theorem}[comments]... and \cite[comments]{refname} work fine, assuming the comments of the Theorem contain nothing crazy, and assuming that \cite is outside the comment environment of the Theorem. But together, such as in the following minimal code  \documentclass{article} \usepackage{amsmath, amssymb, amsthm} \newtheorem{Theorem}{Theorem}  \begin{document} \begin{Theorem}[see \cite[Theorem 12]{refname1}] \end{Theorem}  \bibliographystyle{plain} \bibliography{b} \end{document}   I get the error      ! Argument of \@citex has an extra }.   Note that it happens already before Bibtex is run, that is when the compiler hasn't read what refname1 refers to. And running Bibtex doesn't change anything.  Any idea where this could come from or how to fix it?

How do I create something like this without getting any errors?  \begin{thm}[\cite[page 10]{ABC2011}] ... \end{thm}   I tried putting various things into {...} brackets, but not eliminating any errors. I probably have misunderstood something about how LaTeX works in the background and the AMS packet:  \usepackage[amsmath,thmmarks]{ntheorem}


I have two sting lists  List<string> list1=new List(){"1","2","3"}; List<string> list2=new List(){"1","2"};   What will be the easiest way to check if list1 contains the values in list2.

Given two sets of values:  var subset = new[] { 2, 4, 6, 8 };  var superset = new[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };   how do I determine if superset contains all elements of subset?  I have come up with this:  superset.Intersect(subset).Count() == subset.Count()   Is this the most logical and efficient method?


I am writing a program to find perfect numbers. The first step in doing this is to find all of the factors of a number. I need some code to find the factor of a number and save the factors to an array (NOT print the numbers). This is what I have so far, but it returns a NullPointerException:  public static int[] getFactors(int number) {     int factorNumber = 1;     int varArrayStoreID = 0;     int[] factors = null;      while(factorNumber <= number){         if(number % factorNumber == 0){             varArrayStoreID = varArrayStoreID + 1;             factors[varArrayStoreID] = factorNumber;         }         factorNumber++;     }      return factors; }   Thanks.

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


The coefficient of determination, $R^2$, is an empirical quantity. What population quantity does it estimate and are there other estimators for this quantity? I am particularly interested in the fixed design, and not the multiple correlation coefficient, which corresponds to a random design.   References appreciated.

I am interested in getting an unbiased estimate of $R^2$ in a multiple linear regression.  On reflection, I can think of two different values that an unbiased estimate of $R^2$ might be trying to match.    Out of sample $R^2$: the r-square that would be obtained if the regression equation obtained from the sample (i.e., $\hat{\beta}$) were applied to an infinite amount of data external to the sample but from the same data generating process. Population $R^2$: The r-square that would be obtained if an infinite sample were obtained and the model fitted to that infinite sample (i.e., $\beta$) or alternatively just the R-square implied by the known data generating process.   I understand that  is designed to compensate for the overfitting observed in sample $R^2$. Nonetheless, it's not clear whether adjusted $R^2$ is actually an unbiased estimate of $R^2$, and if it is an unbiased estimate, which of the above two definitions of $R^2$ it is aiming to estimate.  Thus, my questions:   What is an unbiased estimate of what I call above out of sample $R^2$? What is an unbiased estimate of what I call above population $R^2$? Are there any references that provide simulation or other proof of the unbiasedness?


I have a list like this:  [(0, 1), (0, 2), (0, 3), (1, 4), (1, 6), (1, 7), (1, 9)]   That I need to convert to a tuple that looks like this:  [(0, [1, 2, 3]), (1, [4, 6, 7, 9])]   This is the code I have:  friends = open(file_name).read().splitlines() network = [] friends = [tuple(int(y) for y in x.split(' ')) for x in friends] return friends

I haven't been able to find an understandable explanation of how to actually use Python's itertools.groupby() function.  What I'm trying to do is this:  Take a list - in this case, the children of an objectified lxml element Divide it into groups based on some criteria Then later iterate over each of these groups separately.  I've reviewed , but I've had trouble trying to apply them beyond a simple list of numbers. So, how do I use of itertools.groupby()?  Is there another technique I should be using?  Pointers to good "prerequisite" reading would also be appreciated.


The question is self-explanatory. A person that rose up from the american poverty line to become rich and famous.

Is there a single word (noun) that describes someone who was born into a lower social class family, but struggled along to a higher social class with his/her own efforts? Idioms are also welcome.  For example, I have a friend who is such a person. He has very uneducated parents who also had a lot of financial problems when he was a kid. He grew up with no toys, with clothes from his older siblings, without much of a social environment. His parents just attended primary school before they immigrated to Europe, so his parents also could not guide him and motivate him for education. He was, however, able to graduate from one of the best technical universities without any support of others, including his parents.  I wanted to tell him that he is a ______, but I did not know what word would fit to describe him.


Initially when i tried to undo, the answer google brought up was outdated, and I pressed ctrl+alt+z, then I did a little more digging, and pressed ctrl+z, that STILL didn't revert to any earlier edits, so I went to the edits menu, and looked through my edit history, when I pressed edit, something happened and my model looked something like this:

So I was just modeling a Pokeball to upload to Deviant Art for fun. And as soon as I left the live preview in object mode as seen here(Picture 1),   I went to start adjusting the camera only to be greeted with this(Picture 2).  The mesh is still fine in edit mode. I am just wondering what it is and why Blender is replacing the spheres with what would belong to a science fiction game.   Thanks in advance :)