Let G be a group. The function $f:G \rightarrow G$ defined by $f(x)=x^2$ is a homomorphism iff G is abelian.  I am having trouble with the 2nd part of the proof.  Proof:  Assume the function $f:G \rightarrow G$ is defined by $f(x)=x^2$ then:   Assume $f$ is a homomorphism then $f$ satisfies the property: $$ f(xy)=f(x)f(y) $$   where $x,y \in G$  Notice how: $$f(xy)=(xy)^2=xyxy$$ $$f(x)f(y)=x^2y^2=xxyy $$  Since $f(xy)=f(x)f(y)$ then by substitution:  $$xyxy=xxyy$$  Multiplying the right by $y^{-1}$ and the left by $x^{-1}$ then:  $$yx=xy$$ which means G is abelian   Assume G is abelian, we want to show $f$ is a homomorphism   For the 2nd part of the proof, would I just work backwards from the first part of the proof? Here is an outline:  then for $x,y \in G$  $$yx=xy$$ by definition of abelian groups.  Multiple the right by y and the left by x, we have:   $$xyxy=xxyy$$  which is equal to: $$(xy)^2=(x)^2(y)^2$$  since we are given $f(x)=x^2$ then translating this to the above statement: $$f(xy)=f(x)f(y)$$  which satisfies the property of homomorphism.  Does that look right?

I'm working on the following problem:     Let $G$ be a group. Prove that $G$ is abelian if and only if   $\varphi(g) = g^2$ is a homomorphism.   My solution: First assume that $G$ is an abelian group and let $g, h \in G$. Observe that $\varphi(gh) = (gh)^2 = (gh)(gh) = g^2h^2 = \varphi(g)\varphi(h)$. Thus, $\varphi$ is a homomorphism.  I'm having trouble completing the proof in the reverse direction. Assume that $\varphi$ is a homomorphism. We then know that $\varphi(gh) = \varphi(g)\varphi(h)$ and $\varphi(hg) = \varphi(h)\varphi(g)$. However, I don't see a way to use this to show that $gh = hg$.  Could anyone lend a helping hand?


The ring of the darkhidden wondrous item has been published in both MoF and MIC. I assume Magic of Faerûn was printed before Magic Item Compendium, but I want to know for sure. There is a similar , so why not 3(.5)e? The reason that I say 3(.5)e instead of 3e or 3.5e is because some people are willing to allow/use (unupdated) 3e material in their 3.5e game, and , like Savage Species and Book of Vile Darkness. I am particularly interested in 3.5e. The reason that I say "material" is I don't assume that all crunch/rules/mechanics (and things that may-be-more-fluff-but-may-have-an-effect-on-crunch) were printed in books. For example, magazines and web articles may not be considered books.  So, can we have a chronological list of 3(.5)e material?

I'm new to d20. I recently acquired a bunch of D&D books and I'm sure they are all either 3.0 or 3.5, but it doesn't say in the book which version it is. How can I tell which version the book is?  For instance, I have "Complete Warrior - A Player's Guide to Combat for All Classes". It's hard back, published in '03. Is it 3.0 or 3.5?  Another example, I have "Sword and Fist - A Guidebook to Fighters and Monks". Perfect Bound, published in '01. Is it 3.0 or 3.5?


My character has a  that contains a wand of .   Taking the wand out of the haversack is a move action. Activating the wand is an immediate action.  How many seconds would it take once he starts falling for a character to take the wand out of his haversack and activate the spell?   If it's easier to answer another way: how many feet would he fall before being able to activate the wand and stop his fall? As a reference, .   A similar question is asked , but I've read that thread carefully and I don't see a clear answer to my question. Having read that, I do not know what the answer is.

If a character falls from a great height and has a skill or item that may save them if used early enough, how does one determine where in the fall the item is used? Depending on the reason for the fall, there may of course be some DC to avoid falling in the first place (usually a Reflex check against the DC of the trap that's opening up beneath you) but what I'd like to know is what happens once it's decided that the character is definitely going to fall.  For example, say I have some kind of teleportation effect that can get me back on solid ground, but the rules say that it doesn't affect my momentum, so if I'm falling at speed I'll still hit the ground hard when I emerge wherever I teleport to. So, this will only save me if I can do it fast enough - for D&D3.5e that's basically before I've fallen ten feet (or twenty if I can make a DC 15 Jump or Tumble check to negate damage from the first ten). How do we determine if I manage that? Can we assume I make it if the activation of the effect is fast enough? Is there another check? My instinct is that it'd be another Reflex check, but I'm not sure what the DC would be.


Towns/cities are surrounded by a kind of swirling & confusing energy storm or field.  In my mind's eye it was blue/purple in color.  The towns/inhabited regions are in bubbles of normal environment.  This fantasy (or perhaps SF) world has special guides able to lead caravans between the towns/cities, without which the caravans would become hopelessly lost.  In one of the books, I think it's revealed that the energy fields between cities can charge people up with (magical?) power.  I think only the guides are able to use this power.  I vaguely associate this story with Roger Zelazny but I can't find anything in his bibliography that looks like this trilogy(?).  These books would have been published no later than the late '80s.

Fantasy/scifi combo - band of travelers who must get from "sphere" or domain to domain - each geographic area is ruled by a magician - it turns out later these are people who are unwittingly tapping into the computer grid they all live on to alter their own reality?


How many zeros are there in $25!$?  I don't know how to really calculate it the number of zeros in the right hand can easily find by .  That gives us:  $\lfloor{\frac{25}{5}}\rfloor+\lfloor{\frac{25}{25}}\rfloor=5+1=6$  But I got stuck with finding the zeros between.Any hints?

One common math puzzle I've seen around asks for how many zeros are in the product of "100!"  Usually, the solution everyone gives goes something like try to match pairs of 5s and 2s that factor out of the numbers, which ends up being 24 zeroes (you can factor a 5 out of 20 of the numbers, and factor 2 5s out of 4 of the numbers; you can factor more than  24 2s out).   This however as far as I know gives the number of trailing zeroes at the end of the number, but does not account for the zeroes that are within the number. My question is, is this answer correct anyways? Can there be zeroes that aren't trailing that are inside? Why or why not and if there can be can we somehow figure out how many are within the product?   Thanks


Some mathematical patterns stay true for a set of integers $1..n$ only to break at $n+1$.   What are some nontrivial examples where $n$ is ``large''?  As an example $x^2+x+41$ is prime for $x=1..40$, but not at $41$.   I am particularly looking for examples other than . Especially examples suitable for an introductory class.

I just came back from my Number Theory course, and during the lecture there was mention of the Collatz Conjecture.  I'm sure that everyone here is familiar with it; it describes an operation on a natural number – $n/2$ if it is even, $3n+1$ if it is odd.  The conjecture states that if this operation is repeated, all numbers will eventually wind up at $1$ (or rather, in an infinite loop of $1-4-2-1-4-2-1$).  I fired up Python and ran a quick test on this for all numbers up to $5.76 \times 10^{18}$ (using the powers of cloud computing and dynamic programming magic).  Which is millions of millions of millions. And all of them eventually ended up at $1$.  Surely I am close to testing every natural number? How many natural numbers could there be?  Surely not much more than millions of millions of millions. (I kid.)  I explained this to my friend, who told me, "Why would numbers suddenly get different at a certain point?  Wouldn't they all be expected to behave the same?"  To which I said, "No, you are wrong!  In fact, I am sure there are many conjectures which have been disproved by counterexamples that are extremely large!"  And he said, "It is my conjecture that there are none! (and if any, they are rare)".  Please help me, smart math people.  Can you provide a counterexample to his conjecture?  Perhaps, more convincingly, several?  I've only managed to find one! (Polya's conjecture). One, out of the many thousands (I presume) of conjectures. It's also one that is hard to explain the finer points to the layman. Are there any more famous or accessible examples?


I need some help regarding LED chips and compatible drivers.  I previously included too little detail and spec's so here it is. I have a 50w RGB chip, voltages are red 16-20, green 24-28, and blue 24-28, it requires 350mA constant current.   I also have a 50W driver that is for warm white LED, the driver is 30-36v and runs at 1.5A, so it drives too high an amperage. I'm wanting to know if I can run RGB chip on such driver, and if a device such as buck or step down will let me do this, any help greatly appreciated.

I previously asked  regarding 50W RGB multi chips and 50W warm white drivers. Here is , a 50W RGB chip draws much lower amperage and compatible drivers usually max out at 650 milliamperes.  Most of my question was kindly answered in last post, but with the above driver, could I run my 50W RGB chip? Would devices such as "buck" and "step down" enable me to do this?


In Terminal, I used, useradd liao2, as I would also do in Linux, but it failed:  useradd liao2 -bash useradd: command not found   I also tried using sudo:  sudo useradd liao2 Password: sudo: useradd: command not found   How can a user be added from Terminal?

Is there any way to add, remove, or modify user accounts via the command line? I'm not talking about an account for a system process or daemon, I mean is there any way to add a user account, change, user real names, icons, FileVault protection, Admin/normal/limited user status, and basically do everything else that can be done in the System Preferences Users preference pane, but via some command line utility?


I want to prove that if A is onto then its transpose is one-to one. Here $A\in R^{nxm}$.

Let $V$ and $W$ be $F$-vector space, and $V^*$ and $W^*$ be the dual space of $V$ and $W$, respectly. Let $T:V \to W$ be a linear transformation. Define $T^*:W^* \to V^*$ by $T^*(f)=f\circ T$ for all $f\in W^*$. Show that $T$ is onto if and only if $T^*$ is one to one. My attempt: $T$ is onto $\implies$ $T^*$ is one to one: Since $T$ is onto, given $w\in W$, $\exists v\in V$, such that $T(v)=w$. Then, if $f,g\in W^*$ such that $T^*(f)=T^*(g)$, then $f\circ T\equiv g\circ T$,so $f\circ T(v)=g\circ T(v)$ $\forall v\in V$. For that given $w$ we earlier mentioned $f(w)=f(T(v))=g(T(v))=g(w)$, and since $w$ is arbitrary, we have $f\equiv g$. But the other direction of the proof I got stuck: $T^*$ is one to one $\implies$ $T$ is onto : Since $T$ is one to one, $\ker(T)=\{0\}$..., and I can't go further, thanks for help! Thanks martini, I have a typo, it should be proving $T^*$ is one to one $\implies$ $T$ is onto, does it use the same way?


I want my applications to be moved between workspaces with only keyboard in MAC OS SIERRA  Is it possible to move application to next workspace by    any open source free tools ? any  workflows? using  tool   This is possible in ubuntu via compiz-plugins-manager software or just using awesome unity hud :)   As there are possible duplicates of this question mentioned below in the comment section and none of them have answers which works with only key board.  My question is whether the software utilities mentioned above alfredapp, bettertouchtool can be extended somehow to move applications between workspaces ?

I use spaces for having multiple desktops, but often need to move a program from one space to another.  I am aware of the various ways to do that with a mouse:   Click-and-hold on the title bar of window and drag to edge F8 to show all Spaces and drag to desired location Click-and-hold on the title bar, and use Ctrl+# or Ctrl+Scroll Arrow   But have not been able to find a keyboard-only method. I use Linux for one of my primary workstations which has this ability and I would LOVE to use it with OSX as well.


In the late '70s or early '80s, I was looking at books at Tower Books - remember them?  There was a sci-fi novel about mercenaries in Southern Africa who were in a firefight. They were outnumbered and had to flee.  They ran into a craft which took off. Turned out to be piloted by aliens. The aliens either talked them or forced them to become mercenaries for them.  May have some of the facts wrong.  Drove me nuts over the years.  Would look for it at book stores but there are so many sci-fi novels.  Does anyone remember this?  Word of advice - if a book looks interesting, buy it!

I read this in the mid '80's or early 1990's. A group of heavily armed elite Earth soldiers is kidnapped just as they were about to be overrun and annihilated. Given the choice of being returned to their certain doom, or taking part in an off world adventure, they get recruited to guard an alien crop from attack from the earlier, less technologicaly advanced bands of soldiers that were captured and recruited to guard the previous seasons of the alien harvest from earlier recruits. Oh yeah. (I think) They ride centaurs.


I'm trying to edit the resolv.conf file on my ubuntu 16.04 instance, but I'm unable.   Here are the first two lines of the file:   # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)  #     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN   Please help me to find out how to fix it.  Edited: Here's the entire file  # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) #     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver 62.210.16.6 nameserver 62.210.16.7 search online.net   I'm trying to edit this file to connect my domain to this server. Any type of edits in this file is overwritten with the exact same lines.  It is a fresh new installation and yes I'm using "sudo".

I need help figuring out why my resolv.conf keeps changing to this, causing me to not be able to access the outside internet and only the local network:  $ cat /etc/resolv.conf nameserver 192.168.16.1 domain localdomain search localdomain   I thought I fixed it by getting rid of the loopback interface and adding in the eth0 interface in /etc/network/interfaces with the instructions on .  I've tried things like doing:  $ sudo ifconfig eth0 down $ sudo ifconfig eth0 up $ sudo /etc/init.d/networking restart $ sudo dhclient   And then things would work temporarily, and eventually the nameserver in resolv.conf would get reverted again.  P.S. I also posted this on .    Edit: There is at least one other program besides NetworkManager that's writing to resolv.conf, and I know this because when I refresh NetworkManager, the resolv.conf file that gets generated has a comment that says # Generated by NetworkManager, and the version that it keeps changing to does not.  So I am trying this:  while true; do echo listening; lsof | grep /etc/resolv.conf; echo sleeping; sleep 1; done    Edit 2:  Adding output of files:  $ cat /etc/network/interfaces  auto lo iface lo inet loopback  auto eth0 iface eth0 inet dhcp   No such file as /etc/NetworkManager/NetworkManager.conf  $ sudo cat /etc/NetworkManager/system-connections/Auto\ Ethernet   [connection] id=Auto Ethernet uuid=#######omitted####### type=802-3-ethernet autoconnect=true timestamp=1314377063  [ipv4] method=auto ignore-auto-routes=false ignore-auto-dns=false dhcp-send-hostname=false never-default=false  [802-3-ethernet] speed=0 duplex=full auto-negotiate=true mtu=0  [ipv6] method=ignore ignore-auto-routes=false ignore-auto-dns=false never-default=false


We all know that electrostatic PE between 2 point charges is kq1×q2/r.But what is PE between a hollow uniformly charged sphere of radius R and charge Q ??

Let there be a hollow sphere (Throughout the question we will ignore the thickness of the sphere) which is positively uniformly charged,q of radius,  R. Suppose there to be a test positive charge, q' at point P which is r distance away from the hollow sphere(r>R, P is outside of hollow sphere).  Now I have an doubt on evaluating Electric Potential,V at point P.  Both source charge,q and test charge,q' are +ve, so source charge will repel the test charge which will make the charge, q' to go to infinity.I have to apply external force, F' to displace the charge, q' from infinity to point P against the equal but repulsive force, F.In short, F' is  displacing the q' from infinity to P.  So External Force, F' will do +ve work and Repulsive Force, F will do -ve work. This way the Electric Field,E produced by hollow sphere is Opposite to Displacement of test charge(i.e.,θ=180).  Now we know that E=k(q/(r^2))  [Please Notice that infinity is the lower limit of integration]  Also V=-∫r∞(E dr cosθ)=-∫r∞(E dr cos 180)=∫r∞(E dr)  At last I ended up to V=- k(q/r). I know that V=k(q/r).  I just want to know why I am having this shitty negative sign in my equation.


I am making an apple with a face and I made the actual body and the face separate. Both parts are in different files and I was wondering how I can merge them into one file so I can attach them together.

I have created several designs for a particular project and they are related, but I don't want to have to keep recreating any similar elements, such as shared materials or textures.  How can I use the existing data in a new Blender file?


I'm trying to pass '?' and '=' symbols to a page using routing.yml  company.calc:   path: '/form?company={nid}'   defaults:     _controller: FrameworkBundle:Redirect:redirect     _title: 'Calc'  requirements:    _permission: 'access content'   but the symbols are transcoded to HTML-entities. It looks like form%3Fcompany%3D%3Fcompany%3D18141 and leads to page 404.  Any ideas how to pass the string like   /form?company=1234    ? This string is necessary to prepopulate the form's field.  Find the same question  but no reply, no solution :(.

I have tried a few things and I cannot manage to make this working.  My route is the following.      amu_hal.publicationsPerYear:       path: '/publications/{year}'       defaults:         _controller: '\Drupal\amu_hal\Controller\AmuHalController::publicationPerYear'         _title: 'publicationPerYear'         year: 2016         route_parameters:           url: 'default'       requirements:         _permission: 'access content'   The code for the controller is the following.      public function publicationPerYear($year,$url) {       $url=urldecode($url);       $url .='&fq=producedDateY_i:' . $year;        try {         $client = new Client();         $response = $client->request('GET', $url);         $content = json_decode($response->getBody(), true);         // ...       }     }   The request  gives the following error:     RuntimeException: Controller "Drupal\amu_hal\Controller\AmuHalController::publicationPerYear()" requires that you provide a value for the "$url" argument (because there is no default value or because there is a non optional argument after this one). in Drupal\Core\Controller\ControllerResolver->doGetArguments() (line 165 of /var/aegir/platforms/drupal8-dev/core/lib/Drupal/Core/Controller/ControllerResolver.php).


I'm doing an insert in mysql but all my accents and "ñ"  changes to "?".  I serched  in internet and I've done this:  I changed the collation of my data base and tables to utf8_spanish_c I changed my php.ini in default_charset  but I have the problem yet.  what can i do?

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


Are there any ways to restore your ability to cast  after suffering from the stress described in the final paragraph and losing your ability to cast it?  From the description:     The stress of casting this spell to produce any effect other than duplicating another spell weakens you. After enduring that stress, each time you cast a spell until you finish a long rest, you take 1d10 necrotic damage per level of that spell. This damage can't be reduced or prevented in any way. In addition, your Strength drops to 3, if it isn't 3 or lower already, for 2d4 days. For each of those days that you spend resting and doing nothing more than light activity, your remaining recovery time decreases by 2 days. Finally, there is a 33 percent chance that you are unable to cast wish ever again if you suffer this stress.

When used in ways beyond the standard outlined uses,  carries a risk of stress:     Finally, there is a 33 percent chance that you are unable to cast wish ever again if you suffer this stress.   Assume here that a DM would resolve this using a d100 roll.  Are there any features/abilities in the game that can work to reduce the chance of this happening (either by modifying the roll or by some other method) when using wish in this way?


I'm trying to set up all six triple integrals to find the volume of the solid that lies in the first octant bounded by the coordinate planes, the plane  $y + x = 4$, and the cylinder $16 - 4z^2 = y^2$.  $3$D graph    I've been able to set up the triple integrals for every other combination except for $dydxdz$ and $dydzdx$, which I am struggling to find the bounds for. I know the volume is $8\pi - 32/3$, but I keep getting an incorrect answer when I set up and calculate dydxdz and dydzdx.  Here's my equation for the projection onto the $xz$-plane, but I'm not sure it is correct/complete:  $xz$-plane projection?    I'd appreciate any help regarding how to find the bounds of dydxdz and dydzdx.

I'm trying to set up all six triple integrals to find the volume of the solid that lies in the first octant bounded by the coordinate planes, the plane $y+z=2$, and the cylinder $x=4-y^2$.  $3$D-Graph:    I've been able to set up the triple integrals for every other combination except for $dydxdz$ and $dydzdx$, which I am struggling to find the bounds for.   I know the volume of the solid is $20/3$, but no matter what I try I haven't been able to come up with $dydxdz$ and $dydzdx$ to produce that result. Looking at the $3$D graph, the projection onto the $xz$-plane appears to be the equation $z=2-(4-x)^{1/2}$ and $x=4$ (see image below), but I don't think that is correct since it isn't producing the correct volume.  $xz$-plane projection?   If that isn't correct, what does the projection look like?  I'd appreciate any help. Thank you!


We know that magnetic does not do any physical work . Now consider; we attached a magnet in a wall with help of a tape. Now we bring a magnet near to other magnet and released we see that magnet will displace towards other magnet. How was the work done on the second magnet to traverse the distance ?

I learned that the force from a magnetic field does no work. However I was wondering how magnets can be used to pick up pieces of metal like small paperclips and stuff. I also was wondering how magnets can stick to pieces of metal like a refrigerator?


I have a raster data in TIFF format which represents land use categories (urban, forest, agriculture etc). This I made in ArcGIS where it is possible to see all categories in different unique colors but I can't see those categories when I opened that file in QGIS.

In ArcMap, it is possible to automatically calculate the unique values for a raster and then apply a different style to each unique value (see 1st image).  However, in QGIS, I have to manually add values for styling when using the "Singleband pseudocolor" style (see 2nd image). Is there a way of auto-populating the unique values like ArcMap does?  ArcMap:    QGIS (how to auto-populate the value list with unique values?):


The system of equations are:  $\begin{cases}x+y+kz = 1\\x+ky+z=1\\kx+y+z=1\\ \end{cases}$  I am looking to finding values of $k$, for which this system has either no solutions, infinite many solutions or a unique solution (if any).  I've had a look around the web for some help, and know that this question has been asked, but in a way that I have not yet learnt (something to do with determinants I think).  However, I have only been working with reducing the matrix to REF/RREF and thus I'm trying to find rows, such as $( 0 \ 0 \ 0 \mid 2)$ and $( 0 \ 0 \ 0 \mid 0)$ etc to show if we have no solutions or infinite many solutions, for instance.  So far, I've got the following:  $\left[\begin{array}{ccc|c}1&1&k&1\\1&k&1&1\\k&1&1&1\end{array}\right]$  Then, $R_2$$\mapsto$$R_2-R_1$  $\left[\begin{array}{ccc|c}1&1&k&1\\0&k-1&1-k&0\\k&1&1&1\end{array}\right]$  Then, $R_2$ $\leftrightarrow$ $R_3$   $\left[\begin{array}{ccc|c}1&1&k&1\\k&1&1&1\\0&k-1&1-k&0\end{array}\right]$  This is where I got stuck, and I'm not sure how to continue.  Thank you in advance, and I'm sorry if this question has been asked and solved in the same way as presented above.  Cheers.

For which real values of t does the following system of linear equations:  $$ \left\{  \begin{array}{c} tx_1 + x_2 + x_3 = 1 \\  x_1 + tx_2 + x_3 = 1 \\  x_1 + x_2 + tx_3 = 1 \end{array} \right.  $$  Have:  a) a unique solution?  b) infinitely many solutions?  c) no solutions?  I haven't done linear algebra in almost a year, so I'm really rusty and could use some pushes in the right direction.


I have run:  sudo apt-get upgrade && sudo apt-get update sudo apt-get dist-upgrade sudo apt-get autoremove sudo apt-get autoclean   but same :(  Here's log:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  wine1.7 : Depends: wine1.7-i386 (= 1:1.7.34-0ubuntu1~ppa1)         Recommends: gnome-exe-thumbnailer but it is not going to be installed or  kde-runtime but it is not going to be installed E: Unable to correct problems, you have held broken packages.

Occasionally, when I'm installing stuff, I get an error like the following:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?


I did not like unity desktop.I want to install kde desktop enviorment.Please help!!!

I want to have both KDE and Gnome shells on Ubuntu. Ubuntu only has Gnome installed by default. How do I install KDE?


I need to link my table with another one which is in different database(say table logs in device db and table accounts in user db, both on same server). So using  I create a foreign table(I check it with running select * from accounts; in device db which works successfully).  But I could not create a foreign key to foreign table from device db still  CREATE TABLE public.logs (   id bigint NOT NULL DEFAULT nextval('logs'::regclass),   ...   account_id bigint,   ...    CONSTRAINT logs_account_id_fkey FOREIGN KEY (account_id)       REFERENCES public.accounts (id) MATCH SIMPLE       ON UPDATE NO ACTION ON DELETE NO ACTION  )   The error message is  ERROR:  referenced relation "accounts" is not a table ********** Error **********  ERROR: referenced relation "accounts" is not a table SQL state: 42809

It seems to be disallowed to add a Foreign Key constraint to a foreign table.  Is there any other way to do this?  My two tables have these constrains on the remote server.    More specific details:  I only really need it as an annotation because some tools look that up for JOINs.  I have two tables on a remote server that I've added to my local using postgresql_fdw's CREATE FOREIGN TABLE.  These I'm using in PostgREST, an automatic API server uses the REFERENCES information in order to make joins.  Actually, I'm further making two additional CREATE MATERIALIZED VIEW to make the lookups fast - but sadly, they too don't have any way I know of to add REFERENCES information?  I'm open to other ways of making (read-only) lookups fast for these tables on the foreign API server and where Foreign Key constraints will work.


Would this look natural:     StackExchange is a helluva site! I found out about this site at Facebook.    Or should we use the preposition on:     StackExchange is a helluva site! I found out about this site on Facebook.    Or are both okay?   (Inspired by a )

I normally use 'on' with mentioned site whereas I would like to know the main reason behind it. I am wondering that should I always use 'on' with related sites? To put it more clearly,  I saw your message on [ Internet | Facebook | Twitter | LinkedIn | and so on]. I wrote you another comment on [ Internet | Facebook | Twitter | LinkedIn | and so on].  How about 'in'?, would 'in' be used for the same purpose?


UPDATE: I am able to save the progress, and make the added layer actually show up in the TOC, by using mxd.saveACopy rather than mxd.save():  mxd.saveACopy(r"W:\for\RSI\DKL\General_User_Data\gamos\Projects\01_Tenures_Mobile_Map\Highway_intersections_2.mxd")  The downside is this way requires me to create a new .mxd, rather than save to an existing .mxd     I am trying to add a layer file to the TOC in using the arcpy.mapping.AddLayer method in Python, but it won't show up:  arcpy.mapping.AddLayer(df, lyr, "TOP") arcpy.RefreshActiveView(),arcpy.RefreshTOC()  layers = arcpy.mapping.ListLayers(mxd) #Returns the object list of layers print"Here are the layers in the TOC:" print"========================================" for layer in layers:     print layer.name   df and lyr are objects, "TOP" is the position it should be inserted.  After I do addLayer, I grab the ListLayers object from the mxd, then print out all the individual layers. It's there - so why can't I see it in the TOC in ArcMap ??  Here is how I grab my mxd and df objects, add the Layer, and (attempt) to save the .mxd:  mxd = arcpy.mapping.MapDocument(r"W:\for\RSI\DKL\General_User_Data\gamos\Projects\01_Tenures_Mobile_Map\Finding_FSR_highway_intersections.mxd") print (str(mxd) + " extracted OK")  #df = mxd.activeDataFrame df = arcpy.mapping.ListDataFrames(mxd, "Layers")[0] print (str(df) + " extracted OK")  arcpy.mapping.AddLayer(df, lyr, "TOP")   arcpy.RefreshActiveView() arcpy.RefreshTOC() mxd.save() #this will run inside the script OK, will run from an external script only if the mxd is closed ???

I want to use arcpy.mapping to make some changes to a mxd.  I am using the Spyder environment for python.  To change the title I can use the following code:  import arcpy  myMap = r'C:\path_to_mxd\myfile.mxd' mxd = arcpy.mapping.MapDocument(myMap) mxd.relativePaths = True mxd.title = 'Title' arcpy.RefreshActiveView() mxd.save()   I can't execute mxd.save() on an open mxd file though.  Is there a way to make changes to an open file and view any code I execute on the fly?


I'm creating a poker mini-game in Minecraft and I need a command block to be able to select two items, from a selection of 52, and give them to the player. So for example, I have three cards and I want the command block to choose two of them and give them to a player and then leave the last one sitting.  Here is the command's I would use to distribute:  /give @p minecraft:paper 1 0 {display:{Name:"Ace of Spades"}}  /give @p minecraft:apple 1 0 {display:{Name:"Four of Spades"}}  /give @p minecraft:redstone 1 0 {display:{Name:"Three of Spades"}}   How would I do this? I know it sounds like a request but I am unsure where to start here. I have tried making a randomizer with scoreboard objectives by setting the score of the player to a number below 52 ( <=) but that did not work.  That ^ is not a smiley face. :)

I want to make a mini game in Minecraft were I need a random command generator for 9 commands. I need a random command to give the player a random item. I can't do the command block in the dispenser any more because it will just drop out instead of being placed. What different ways are there for generating randomness in commands, and which one would be best for my use? This question is similar to the one about , but I am specifically attempting to get randomness when using commands - the redstone solutions do not apply here.


I'm doing some automation in my work using Python, I basically created a fairly simple GUI with several options, whenever to user click in one of these options the app creates a new thread with the deamon flag set to true.  Happens that most of the time everything works flawlessly, except when something that was not planned happens, then I have to manually kill the application while it keeps pressing buttons and clicking everywhere, I'm already using the safe flag from the PyAutoGui from putting the mouse on the top left corner of the screen, but this isn't quite user-friendly for users that are not so familiar with technologies, I wish I could set a key in the keyboard to act a safety switch, whenever the user press this key all the threads except the main one should be killed.  I know that there is a lot of content available about that, but I'm just a simple guy that knows some stuff about coding and I didn't quite understand how this is supposed to work, could you clarify how can I stop all threads? Or point me to some good reading material?

Is it possible to terminate a running thread without setting/checking any flags/semaphores/etc.?


I'm trying to figure out what's going on with Apple's ratings/reviews system on the App Store. I've had issues with my own app (ratings/reviews not showing) now I see a major app with similar issues...  The Sports Illustrated Swimsuit 2011 free app was released just 2 days ago (Feb 14). It now has 29 ratings and 9 reviews (one review is mine posted from night of 2/15). But this has got to be a well downloaded app right? I'm talking 1000's probably just in the first day, so where are the other reviews/ratings?  Does anyone know if:  1) Apple has humans approve all ratings/reviews before letting them show?  2) Apple has an algorithm for passing/rejecting ratings/reviews?  3) What is the exact time delay between posting a review/rating and it appearing on the App Store?  Also-> Have you had any experience with a review or rating not showing in the App Store ever or only after a long delay?

I have an app that's been out for a couple of weeks. Its not exactly selling like hot cakes yet, but I'm pretty sure I've gotten a rating or a review by now. But nothing shows when viewing either in iTunes or directly on the AppStore on the iPhone.  Is there a standard delay as to when ratings/reviews show up, that Apple imposes, especially for new apps? Or do you think there is some problem with Apple's system?


\begin{equation} w \left (\dfrac{x+y}{2} \right ) \le \dfrac{1}{2}(w(x) +w(y)) \quad \mbox{for all}  \quad  x,y \in \Omega, \end{equation} is a sufficient condition to a continuous function $w \in C^0(\Omega)$ be convex?

Given that $$f\left(\frac{x+y}{2}\right)\leqslant \frac{f(x)+f(y)}{2}~,$$ how can I show that $f$ is convex. Thanks.      Edit: I'm sorry for all the confusion. $f$ is assumed to be continuous on an interval $(a,b)$.


I am trying to cite my references in latex using my reference details which are stored in the file references.bib. I referenced as \cite{blah} but it does not work. Does it need some package?

I've browsed the forums and found a number of posts that have addressed this issue, but none of the solutions seem to work for me. I have the following script that I just copied from the bibtex home page to get familiar with it. Instead of the citation number I get a question mark. I compile using Latex+Bibtex+Latex+Latex+PDFLatex+ViewPDF just as has been previously suggested and the problem persists.   \documentclass[11pt]{article} \usepackage{cite}  \begin{document}  \title{My Article} \author{Nobody Jr.} \date{Today} \maketitle  Blablabla said Nobody ~\cite{Nobody06}.  \bibliography{mybib} \bibliographystyle{plain} \end{document}   My bibliography (Bib.bbl)  @misc{ Nobody06, author = "Nobody Jr", title = "My Article", year = "2006" }    Looking at previous posts one thing that is concerning is that my .bbl looks empty as shown below. Further, I don't have a .blg  \begin{thebibliography}{}  \end{thebibliography}


I have a polygon shapefile and a point shapefile. At the point shapefile, I want to create a column, which will inform me about the polygon where each point exists. What do you suggest?  I mainly use QGIS, but I am also familiar with ArcMap.

I want to count points (1000 of students home) in district polygons with Qgis 2.16. I didn't find the tool in the analysis tools plugin.   Is there another plugin or method I could use to perform this task ?


Yeah hi, I was wondering how I could get my images to look like they were shown on 90's TV or were recorded to a VHS and ripped into a digital file. Examples shown below.        I'd like to utalize this effect for a flyer/gigposter I'm making.

How can I create an image in Photoshop that imitates a photo taken with a low-quality phone camera? Examples of qualities I want to simulate:   blurring in some areas caused by a dirty lens low quality exposure handling in the darkroom noise   Some examples:


I was hoping to left align the 'Reason not found' text so that it is in line with the other rows. \begin{table}%[htb!]     \caption{Reasons}     \centering     \begin{tabular}{|p{2cm}|l|l|l|l|}         \hline         \textbf{Scheme} & \textbf{R } & \textbf{Type} & \textbf{State} & \textbf{P} \\ \hline         \multirow{2}{*}{V (3)}          & M (2) & \multirow{4}{*}{S } & Accepted & 2 \\ \cline{2-2} \cline{4-5}          & No M. (1) &  & Rejected & 1 \\ \cline{1-2} \cline{4-5}                   \multirow{2}{*}{P (2)} & M (1) &  & Accepted & 1 \\ \cline{2-2} \cline{4-5}          & No M (1) &  & Rejected & 1 \\ \hline                  \multirow{5}{*}{                           \begin{tabular}{l}Reason\\not found\\(38) \end{tabular}         } & & \multirow{2}{*}{S} & Accepted & 32 \\ \cline{4-5}          &  &  & Rejected & 3 \\ \cline{3-5}          &  & P & Accepted & 2 \\ \cline{3-5}          &  & I & Accepted & 1 \\   \hline  % \cline{2-5}               \end{tabular} \end{table}

I currently have this table:  \begin{table} \centering \begin{tabular}{ |c|c| } \hline no test & no test \\ \hline no test & \begin{tabular}{c|c} D1 & 1.23 \\ \hline D2 & 1.23 \\ \end{tabular} \\ \hline \end{tabular} \end{table}    Giving:    hline in the nested tabular does not span the entire cell width.  Of course multirow/multicolumn would be a choice. However, this is a "mutable" table, to which I will need to add "sub-rows" each time new data arrives, but I do not know in advance where. So, it could become something like:    For such purpose, multirow/multicolumn seems that would require constantly changing their row/column numbers.  How can this be solved in such a way that minimizes the work each time a new "sub-row" is added?  Thanks.


I have the following APEX code I need tested and have found many topics regarding testing these methods but none seem to work.  Please if you have any tips on how to test this method it would be appreciated.    @AuraEnabled(cacheable=true)     public static String getPreviousContractStatus(Id parentId) {          // create new list of all previous Contract amounts         List<String> oldValueList = new List<String>();          //query for OldValue of Contract Status         List<Contract__History> oldValuesContractStatus = [                 SELECT OldValue                 FROM Contract__History                 WHERE Field = 'Contract_Status__c'                 AND ParentId =: parentId                 ORDER BY CreatedDate DESC         ];          // Remove Approval Requested value from list as it always will be OldValue         // when using Close Contract button         if(oldValuesCommitStatus.size() > 0){             for(Contract__History cH : oldValuesContractStatus){                 if(cH.OldValue != 'Approval Requested') {                     oldValueList.add(String.valueOf(cH.OldValue));                 }             }         }          return oldValueList[0];      }   Any help would be appreciated on how to test.

I have some code that relies on field history tracking by querying the History for a custom object. This works fine, but it appears that the history records aren't created during the test so none of my tests will pass.


From Ubuntu I download   ubuntu-16.04.4-desktop-amd64.iso  But I don't see AMD in my motherboard of my computer  Which iso from Ubuntu site, I have to download for my computer?

I was told that computers with more than 2 gig's memory need a 64 bit operating system to utilize all RAM.  Is the 64bit Ubuntu download really JUST for AMD processors? I am asking because the disk image I downloaded says AMD64.  So will my new Intel 2.3Ghz Core i3 Dual Core processor work with 64 bit Ubuntu?  It runs the 64bit version of Windows without any qualm.


I was studying gravity and I came to know about $P.E.= -\frac{GMm}{r}$ which is derived by $GMm(\frac{1}{\infty} - \frac{1}{r})$  which the work done by the body to displace it from infinity to $r$. But, I thought potential energy is the energy which could be converted to kinetic energy or any other visible form but What I see is ,it  is the work done by gravitational force while displacing some body from infinity to $r$. So, I request true meaning of gravitational potential energy and explaining the formula of $-\frac{GMm}{r}$.

In a gravitational field, the gravitational force acting on a body (of mass m) at a point x metres away from the attracting body (of mass M) is $\frac{GMm}{x^2}$. Integrating this force from a point at infinity to x gives $-\frac{GMm}{x}$, or the work done by the gravitational field on the mass in moving the mass from a point at infinity to x. Then, the gravitational potential at point x is $-\frac{GM}{x}$.  However, the definition that my school gives is : "Gravitational potential at a point in a gravitational field is the amount of work done by an external agent in moving one unit of mass from a point at infinity to the point in the gravitational field, without any acceleration". The lecturers explained that as a body moves closer to the attracting body, it accelerates and gains kinetic energy. In order to maintain a constant velocity, negative work must be done by an external agent to remove this extra kinetic energy.  Now I am very confused, because both seem valid to me. What does "gravitational potential" actually mean?


I'm in a writing comp class and my professor is charging the class each a cash fee for a New Yorker magazine which is part of the required classwork. Is this allowed and is it considered ethical, especially knowing there are textbooks and other avenues that she can get our classwork from where we can go through school sources such as our book store or library to get our course work? Personally it is not even the fee I'm worried about, I am worried about a professor taking advantage of her students for her own personal gain, it just doesn't feel right or professional, and it definitely doesn't seem like it is good conduct.

I'm currently taking a class that doesn't have a required textbook, which is why I took it. My professor is now saying that due to her scanning and printing out handouts for use we are each required to give her $15. I'm confused by this because isn't the money supposed to go through my university, as a fee for the class, rather than through her? I just want to know if she's allowed to do this


I have a Samsung laptop a bit old, with Ubuntu 18.04 LTS and an integrated gpu card (Intel HD Graphics 4000), but also a dedicated graphic card : AMD Radeon HD 7600M Series.  The amd driver is not recognized by Ubuntu, only the Intel HD Graphics.  The "additional driver" tool don't help me because he can't find anything..  I don't find the driver for this card on the AMD website.  So, my questions :    can I install the AMD Radeon HD 7610M driver? AMD Catalyst™ 15.9 Proprietary Ubuntu 14.04 x86_64 Video Driver for Graphics Accelerators Revision Number 15.9 - Release Date 9/15/2015.  There arre 4 different files. Which is the good one?   AMD Catalyst™ 15.9 Proprietary Ubuntu 14.04 x86_64 Video Driver for Graphics Accelerators Minimal Video Driver for Graphics Accelerators (Non-X Support)  Video Driver for Graphics Accelerators Devel Files (OGL, OCL)  AMD Catalyst™ 15.9 Proprietary Ubuntu 14.04 x86_64 Catalyst Control Center     I tried a live Zorin OS, and I think the driver was recognized because in the about thing it was written: Intel HD Graphics 4000 / AMD track (I think..). So a driver exists!  Anyone has a solution ?

I'm using Ubuntu 16.04 and there's no fglrx! What happened?


If $\mu$ is semifinite measure and $\mu(E) = \infty$, for any $C > 0$ there exists $F\subset E$ with $C < \mu(F) < \infty$.   Attempted proof - Suppose $E\in M$ with $\mu(E) = \infty$ then there exists $F\in M$ with $F\subset E$ and $0 < \mu(F) < \infty$, $\mu$ is called semifinite. This is the definition from Folland. I am guessing that we have to set $C$ equal to something where the definition still holds true but I am not sure how to do this. Any suggestions is greatly appreciated.

I am trying to solve following exercise from Folland,     If $\mu$ is a semifinite measure and $\mu(E) = \infty$, for any $C > 0$, $\exists$ $F \subset E$ with $C < \mu(F) < \infty$.   It seems to follow from definition of semifinite measures, which you can find , but I couldn't prove it.


While reviewing  I noticed that the URL that was posted as one of the answers looked weird to me:     leopard_9m2809a.dmg">   I clicked on the edit link to see if the user had perhaps posted some broken HTML, but all I found was a bare URL:     http://adcdownload.apple.com/iphone/iphone_sdk_3.1.3__final/iphone_sdk_3.1.3_with_xcode_3.1.4__leopard__9m2809a.dmg     Here's how the above URL renders currently:    (I'm assuming) it should look like this:      EDIT:  I wonder if it has anything to do with the double underscore that is causing the word "leopard" to appear italicized?  Let's try that out by removing the double underscore:    Aha! That must be it.

In the answer , the parser breaks my URL link.  The URL was with __word__:      http://www.open-mpi.de/projects/hwloc/doc/v1.2/group__hwlocality__membinding.php#gade5e2c28ea8475a479bf2b1df36c6ccd   After parsing, it becomes (<a href is broken; no clickable link):  hwlocality_membinding.php#gade5e2c28ea8475a479bf2b1df36c6ccd">http://www.open-mpi.de/projects/hwloc/doc/v1.2/group_hwlocality_membinding.php#gade5e2c28ea8475a479bf2b1df36c6ccd   Short test:  http://example.com/_test_ -> test">http://example.com/test  Or if I put in a naked URL with _test_ just here:


I am using jQuery to replace normal checkbox with image. I am able to replace checkbox with image but unable to set CSS and click handler on image.  This is my jQuery code.    (function ($) {     $.fn.SetOnOff = function (onImage,offImage) {          debugger;          var html = '<img style="width: 80px; height: 30px" src="'+offImage +'"/>';                 $(this).replaceWith(html);          $(html).css('cursor','pointer');           $(html).click(function(){              var fileName = $(this).attr('src');                 if (fileName == onImage)                     $(this).attr('src', offImage);                 else                     $(this).attr('src', onImage);          });                          return  $(this);     }; } (jQuery));     can anybody let me know how to do this?  you use   link to test it

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


I tried installing PlayOnLinux by using the steps according to a YouTube video, , and used the command  sudo apt-get install curl   Then it requested my password which I entered.   Can anyone please explain what this command line does?

I am completely new to linux and hence Ubuntu. Though i have been using the Ubuntu OS on my system for a while, it is for the first time I am trying to learn the nuances and hence starting with the documentation.  I am wondering , if we use apt-get command to install packages, what does apt-get install aptitude do ?


I created a newcommand like this: \newcommand{\txtDBC}[1]{\contour{white}{#1}} and I want to apply it on all text and math formula in a tikzpicture.   The first was to declare a specific font using font keyword:  \begin{tikzpicture}[font=\small] ... \end{tikzpicture}   But my \txtDBC command need one parameter. How can I rewrite it for using it as the \small command? Maybe another solution can be used.   MWE:  \documentclass[]{standalone}  \usepackage{esvect,tikz} \usepackage[outline]{contour} \newcommand{\vecteur}[1]{\protect\vv{#1}} \newcommand{\txtDBC}[1]{\contour{white}{#1}}  \begin{document} \begin{tikzpicture} \node[fill=blue]{\txtDBC{$\vecteur{aa}$}}; \end{tikzpicture} \end{document}   Result:   Expected syntax:  ... \begin{document} \begin{tikzpicture}[font=\txtDBC] \node[blue]{$\vecteur{aa}$}; \end{tikzpicture} \end{document}

I would like to create a TikZ style that adds a thick outline to the node text using the \contour{<colour>}{<text>} macro from the contour package (as in the answer to the question ), i.e. I want to define a style halo so that  \node [halo] {Text};   is equivalent to  \node {\contour{red}{Text}};   My problem is that I cannot tell TikZ to use the node text as an argument for a macro.  The font option only works with switches like \itshape (as opposed to \textit{}, which requires the text to be italicised to be provided in the argument).  There are two keys execute at begin node={<code>} and execute at end node={<code>} that can be used to call code at the beginning and end of the node, but I can't split the \contour command up using execute at begin node={\contour{red{} and execute at end node={}} because the brackets don't match. Replacing { with \bgroup and } with \egroup fails with Missing } inserted.  Here's am MWE to play with:  \documentclass{article}  \usepackage{tikz} \usepackage[outline]{contour} \contourlength{1.2pt}   \begin{document}      \begin{tikzpicture}     \node {\contour{red}{Text}}; %    \node [font=\contour{red}{}] {Text}; % Doesn't change the text %    \node [execute at begin node={\contour{red}{},execute at end node={}}] {Text};  % Fails with ``Runaway argument?'' %    \node [execute at begin node={\contour{red}\bgroup},execute at end node={\egroup}] {Text};  % Fails with ``Missing } inserted''     \end{tikzpicture} \end{document}


I installed the popular software 'Synthesia' from its official website. It is a program for piano transcriptions. It has always been safe.  I decided to uninstall it and as soon as I uninstalled it, a virus came up. I mean, I tried to uninstall it from the Panel Control > Programs [list] > Uninstall a Program.  The uninstall.exe stopped and a warning from Avast came up saying that the .exe has been stopped and the virus [Trojan] moved to the chest [Avast virus chest].  I checked it out and it is quite strange because the name is   au_.exe found in the Temp Folder -- C:/Users/MyUserName/AppData/Local/Temp/~nsu.tmp  As Avast has reported the virus is a FileRepMalware  I decided to scan the computer but nothing has been labelled as infected.  Anyway, the software is still there, not uninstalled. How can I remove it if the uninstaller is infected?  p.s - as far as I know, au_.exe is a virus. au.exe is not a virus, at all. Anyway I got the first one so it is a virus and not a false positive of course!

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


I wanna make something like the table in the picture.So far i only managed to do this:  \documentclass{article} \usepackage{longtable} \setlength\LTleft{-110pt}  \setlength\LTright{\fill}   \begin{document}  \begin{longtable}{lllll}  \caption{Quick guide to GPU terms}\\ \hline \bfseries Type &\bfseries Descriptive name &\bfseries Closest Term &\bfseries Official term &\bfseries Definition\\ \hline \endfirsthead \hline \endlastfoot \hline Program abstractions       &Vectorizable Loop         &Vectorizable Loop       &Grid     &Vectorizable Loop       \\        \hline (put in this space the above title vertically)   &some     &some       &some      &some                                   \\       \hline (same as above)                                        &some     &some       &some      &some                                   \\       \hline  Machine object          &Thread SIMD               & Thread Vector            &  Warp    &      SIMD Processor\\ \hline (put in this space the above title vertically)&some     & some                         &  some      &   some\\                  \hline (same as above)&some                          & some                         &  some      &   some\\                  \hline  Processing Hardware &some                          & some                         &  some      &   some\\                  \hline (put in this space the above title vertically)&some                          & some            &  some      &   some\\              \hline (same as above)&some                          & some                         &  some      &   some\\                  \hline  Memory Hardware     &some                          & some                         &  some      &   some\\                  \hline (put in this space the above title vertically)&some   & some                         &  some      &   some\\               \hline (same as above)&some                          & some                         &  some      &   some\\                  \hline  \end{longtable}  \end{document}   Can anyone point how to do this?

I have a big table with a problem, when I want to rotate the text in a \multirow cell, the text is placed outside and is bigger than the dimensions of the cell, I took some advice from here, using\parbox, and then \rotatebox. But I don't get good results.           \documentclass{article}  \usepackage{array,multirow,graphicx}  \begin{document}  \begin{table}[H]  \centering  \begin{tabular}{|c|l|r|r|r|r|}  \hline  & \multicolumn{1}{|c|}{Text} & \multicolumn{1}{|c|}{Text} & \multicolumn{1}{|c|}{Text} & \multicolumn{1}{|c|}{Text} & \multicolumn{1}{|c|}{text}\\  \hline  \rotatebox{90}{\parbox{2mm}{\multirow{3}{*}{rota}}} & text &&&&\\  & text &&&&\\  & text &&&&\\  \hline  \end{tabular}  \end{table}  \end{document}   Which results in:


Sorry for using this image, but I thought this was the most convenient way of asking this question. Please zoom in.  I do not understand from the line, "Now, in the body frame $T = (T_{x'}, T_{y'}, T_{z'})\ldots$"  How is that in the body frame? That should be in the inertial frame, since it is dL/dt. In the body frame, it is dL'/dt.   How can you treat dl/dt as the torque in the body frame, and then derive the Euler's equation?

I am in search of a simplified version of the derivation of  (both translational and rotational) for a rigid body (3D block) that has a body fixed frame and where the center of mass of the body is not at the center of gravity.  I can find elementary derivations for the same system when the center of mass is at the center of gravity, but not for my system in question.    I am using the derivation as background research for a rotordynamics project that I'm working on.  Any help and or references would be greatly appreciated!  :)


I've just asked this question () and I've got a nice answer... but! Just to understand a little more about JavaScript, I'd like to know if the momoized function can be written in this style:  function main () {     function memoized_f(){         //memoizing code     } }   EDIT: Please notice I'm not asking what is the difference in the code above, I'm asking if it is possible to memoize the second one!  So, how to rewrite this?  function main() {   var create_node = (function() {     var memo;     console.log("memo: " + memo);     console.log("create_node")      function f() {       var value;       if (memo) {         value = memo.cloneNode();         console.log("clone node");         console.log(value);       } else {         var value = document.createElement("div");         value.innerHTML = "hello";         console.log("new node");         console.log("value: " + value);         memo = value;       }       return value;     }     return f;   })();   var collection = [];   for (var i = 0; i < 10; i++) {     collection.push(create_node());   };   // Display results   for (var i = 0; i < 10; i++) {     console.log(i + ". " + collection[i]);   } } main();

I've recently started maintaining someone else's JavaScript code. I'm fixing bugs, adding features and also trying to tidy up the code and make it more consistent.  The previous developer used two ways of declaring functions and I can't work out if there is a reason behind it or not.  The two ways are:  var functionOne = function() {     // Some code };     function functionTwo() {     // Some code }   What are the reasons for using these two different methods and what are the pros and cons of each? Is there anything that can be done with one method that can't be done with the other?


I'm trying to save  locally. I found this  ,but how to use Blob() in my case?  There is one more  but is for Java and i don't know how to use wget in javascript.  Thanks! :)  //Edit 1 I downloaded the file with    wget 'http://api.eventful.com/json/events/search?c=music&app_key=API_KEY&page_number=1&date=Future&keywords=Andrea-Bocelli&callback=processJSONP' -O hi.json   //Edit 2 This  not working for me

I need to do an  request in JavaScript. What's the best way to do that?  I need to do this in a Mac OS X dashcode widget.


I am traveling to Amsterdam (2 nights), Paris (2 Nights), Rome (3 nights) and Zurich (3 nights). However, I am landing in Brussels and then taking a train on the same day to Amsterdam. To which country should I apply for the visa?

My port of entry and exit is Frankfurt, Germany. However i will only be spending a day or two there. I am visiting Spain and Portugal for a week each. So should I be applying to Spain embassy or German embassy? I am an Indian citizen.


I develop an Apex REST web service in Salesforce and I would like to test it with Postman. Unfortunately, I get an error message than I don't understand:  Expected JSON object to deserialize apex parameter from at [line:3, column:14]  This is the JSON I tr to send with postman:     {       "data":  [             {                   "attendantYear":"2014;2015;2016;2018;2019",                   "birthDate":"1981-12-11",                   "city":"New-York",                   "country":"USA",                   "email":"jean-paul.gus@gmail.com",                   "firstname":"Jean-Paul",                   "itra":450,                   "lastname":"Gus",                   "salutation":"Mr."             }       ] }  And this is how looks like my apex web service: @RestResource(urlMapping='/accounts/*') global with sharing class ABT_WSAccounts{      @HttpPost     global static String upsertAccounts(String data){         String result;          System.debug('--- data : ' + data);          if(!String.isBlank(data)){             List<Account> accountsToUpsert = new List<Account>();              List<ABT_AccountInnerClass> sobjects = (List<ABT_AccountInnerClass>) JSON.deserialize(data, List<ABT_AccountInnerClass>.class);             System.debug('--- sobjects : ' + sobjects);              .....         }          return result;     } }  And my inner class: global class ABT_AccountInnerClass{      global String firstname;     global String lastname;     global String salutation;     global Date birthDate;     global String email;     global String street;     global String country;     global String attendantYear;     global Decimal itra;  }  Please, can you explain me the error? Thanks

This is a canonical question and answer developed by the community to help address common questions. If you've been directed here, or your question has been closed as a duplicate, please look through the resources here and use them to shape more specific questions. To browse all canonical questions and answers, navigate to the  tag.  This question and answer is owned by the community! If you can improve it and make it more useful, you're welcome to edit it.  I have a specific JSON structure in mind. I need to either deserialize this structure that's coming in from a web service, or I need to serialize data into this structure to transmit it to another system. How should I get started on this project in Apex?


I have this string :     464-138234-AVENANCE   And I need this output on three items :   464  138234  AVENANCE   For first item I have try with success :  strMyString.SelectedItem.Value.Substring(0, strMyString.SelectedItem.Value.IndexOf('-'))   Output : 464  I can't to extract the two and three items :  strMyString.SelectedItem.Value.Substring(1, strMyString.SelectedItem.Value.IndexOf('-'))   The output is :  64-   Can you help me?  Thank you in advance for any help, really appreciated.

How do you split a string?  Lets say i have a string "dog, cat, mouse,bird"  My actual goal is to insert each of those animals into a listBox, so they would become items in a list box.  but i think i get the idea on how to insert those items if i know how to split the string. or does anyone know a better way to do this?  im using asp c#


While trying to link an IRC channel on a tag wiki, I had to realize that all four ways to create a link in SO's markdown failed. Trying a bit around, I noticed the link would render if I would change the schema from irc to http. It seems https and ftp are working as well. But what else does?  The  doesn't mention which schemata are actually supported. Here on meta, I can only find answers regarding . Am I missing something?

It seems like the engine completely breaks all links that use a URI with a scheme other than 'http' or 'https'. Web != Internet, guys! ;)  For example, the market scheme links to the Android market: market://details?id=com.google.zxing.client.android (<-- if it worked, you'd see a link here)  I can also think of a number of relevant schemes for the Gaming SE, e.g. the steam scheme:     steam://store/400/ (<-- if it worked, you'd see a link here) And various smaller ones which are specific to certain games to install mods, add-ons, etc.  And here's a real life example:  If this link wasn't broken, I could just click it and my phone would start installing the app or show the search results.


We have a  tag, which has no description. What types of questions is this tag meant to be used for?

What is the best long-term solution for the  problem? Adapted from the above article:  Identifying Help Vampires can be tricky, because they look like any ordinary person (or Internet user, whichever is lesser). But by closely observing an individual's behavior using this handy checklist, you too can identify Help Vampires in the field:  Do they ask the same, tired questions others ask (at a rate of once or more per minute)? Do they clearly lack the ability or inclination to ask the almighty Google? Do they refuse to take the time to ask coherent, specific questions? Do they think helping them must be the high point of your day? Do they get offensive, as if you needed to prove them why they should use Ruby on Rails? Are they obviously just waiting for some poor, well-intentioned person to do all their thinking for them? Can you tell they really aren't interested in having their question answered, so much as getting someone else to do their work?


please help me in understanding this doubt. My brain says 'were' but some stupid online rule says was'

Formally, is it correct to write:     A number of questions has been asked here.   or:     A number of questions have been asked here.   As a non-native speaker of English, I would prefer the former: the subject seems to be "number", therefore the verb ought to be singular, I'd say. However, the latter seems more common, and therefore I believe that my gut feeling is just plain wrong — but I would really like to have a definite answer.  Moreover, is it the same for "a myriad of", "a plethora of", and so on?


How can I convert/migrate my own question from one Stack Exchange site to another?

I posted a question which was closed as off-topic and it seems like it could fit on another site in the network. How can I go about moving it there?   What is migration? When can a question be migrated, and who can migrate it? When should I consider migration, and when is it inappropriate? What causes a migration to be blocked and what happens after? What causes a migration to be rejected and what happens after? Anything else I should know about migration?


I want to log in to my Google Chrome browser.   I downloaded the .deb from Google but it would not install. I came to Ask Ubuntu and read that I should download gdebi installer. I did that but I didn't/don't know what else to do.   Then someone said I should install Chromium and I did so.   Now what?

How do you install Google Chrome on Ubuntu?


Going by this question:   Fast Heal will allow a creature to clean up bleed damage quickly, but my question is does it do any damage on the first round before healing kicks in? Or does the opponent get to choose the order.

I've designed for a campaign a duo of rogues. My character is as , and his follower is a Knife Mistress. Couple of question about them. Our party is about to ambush several . My Sniper will hide near their camp, and shoot the weakest one when fight begins. His follower will then rush the troll and slice him in several pieces. My Sniper has the Bleeding attack feat:  Bleeding Attack (Ex) Benefit: A rogue with this ability can cause living opponents to  by hitting them with a sneak attack. This attack causes the target to take 1 additional point of damage each round for each die of the rogue's sneak attack (e.g., 4d6 equals 4 points of bleed). Bleeding creatures take that amount of damage every round at the start of each of their turns. The bleeding can be stopped by a DC 15 Heal check or the application of any effect that heals hit point damage.  Emphasis mine. Thus, a normal enemy would bleed every turn, until he get cleaned of the bleeding effect. However, troll have a special ability, which is  5 (acid/fire)  Regeneration (Ex) A creature with this ability is difficult to kill. Creatures with regeneration heal damage at a fixed rate, as with , but they cannot die as long as their regeneration is still functioning (although creatures with regeneration still fall unconscious when their hit points are below 0). Certain attack forms, typically fire and acid, cause a creature’s regeneration to stop functioning on the round following the attack. During this round, the creature does not heal any damage and can die normally. The creature's descriptive text describes the types of damage that cause the regeneration to cease functioning.  So, the troll will automatically get rid of the bleeding effect during his first turn. My question is: Does the bleeding effect apply before the regeneration, or get neglected, because the troll will heal during his turn? Am I right to assume that, Bleeding attack effect getting triggered at the beginning of the troll turn, it will deal him the damages before the wounds heals?


I saw a number of apps in the Play Store, but I was wondering if there's an official one. I didn't see a link on the homepage. It would be nice to be able to check, and get notifications, on my phone, without having to keep opening a browser (my browser has a bunch of open tabs which makes it worse).

I'm using the official Stack Exchange mobile app for iOS or Android, and  My app crashed! It doesn't look good on my new smartphone. It won't run after I updated my device. I noticed another bug. I have an idea for a new feature which is currently not in the app.  How do I report bugs with or request features for the iOS and Android apps? Also:  I've used the built-in functionality of the app to report a bug or submit a feature request. Did I do the right thing? The app prompted me to post on Meta after an error occurred. Should I post about it here? I'm wondering why the latest version is from 2017. I've heard rumors that the apps are no longer supported; is that true? I can't find the app on my device's app store anymore! Where did it go?     We get a lot of bug reports from users about the mobile apps, which are unsupported, and at the moment, there is no centralized Q&A pair for those to be closed as duplicates of (the relevant answers are spread across multiple unrelated questions). This question is an FAQ proposal, to serve as a directly-related duplicate target for those questions.


I'm trying to activate some command blocks only if there's more than one player online in my vanilla server. Is there a way to accomplish this with command blocks?

I want to run a command when there are only 10 entities left. I know you can use /execute unless entity to detect when all matching mobs have died, but it doesn't work if you want to run a command when there are for example 10 entities left.  A command like /execute if entity @e[limit=10] does not work, it also triggers if there is only one entity.  Such a counting system could also be used to determine once there is only one player left in an arena, meaning they have won a battle or similar.


I have a site that's already on the host. So what I want to do is to put in on my PC , and so I could edit it.  I have already installed WAMP and download a backup with the site from the host, and downloaded the DB from the host also.   What I have to do next?

I have a drupal site running currently on bluehost. The site is big and I want to test every thing I change on local host before doing it on production site.  Unfortunately, I can not move it to from the remote server to local host.  Can someone give me the basic steps needed to move site from remote server to my local host (aquia dev desktop)?


A man wants me to transfer 2.1 million into my account and then have me purchase properties with the money. Am I being scammed? He has given his banking info, Password, and routing information.

A man in  west  coast  Austria wants to deposit money  into  my account.  I'm in Alabama.  I had to get an online  account.  I did that, but he says his bank manager  needs all this information:   DOB SSN    online access username  online access  password   security  question and answer   bank name   bank address   bank number  person who is on the account     their name their address    account no   routing no     OK. Is it safe  to do this or am I being scammed?  I don't want him  to be able to end up withdrawing all my money instead of depositing money.


If $\{s_n\}$ is a sequence of positive real numbers such that $\lim_{n \rightarrow \infty }s_n = s$, is it true that $\lim_{n \rightarrow \infty} \frac{1}{n}\sum_{k=1}^n s_k =s $ as well?

I have this problem I'm working on. Hints are much appreciated (I don't want complete proof):  In a normed vector space, if $ x_n \longrightarrow x $ then  $ z_n = \frac{x_1 + \dots +x_n}{n} \longrightarrow x $   I've been trying adding and subtracting inside the norm... but I don't seem to get anywhere.  Thanks!


During Doctor Who S9E2, The Witch's Familiar,      The Doctor gives away enough of his regeneration energy to revive Davros and every Dalek on Skaro, including all the "dead" ones.   Capaldi was the first regeneration of a new cycle, but surely this event shook things up. How many more Doctors will we have before Moffat has to get creative again?  The events of S9E2 give me a reason to think there would be a different  answer than the one to

In The Time of the Doctor, the Doctor says that he has a "new regeneration cycle". Does this mean he has another set of 12 regenerations, or just the one?


When I try to update my StackExchange profile image I get the following error:     Oops! There was a problem updating your profile: This email address is   already registered. If it belongs to you, log in above or visit our   account recovery page to get access to this account.   Tried in: askubuntu and stackoverflow.  Steps to reproduce:   Open "My Profile" Go to "Edit Profle and Settings" "Change Picture" Update picture (tried with URL and also with direct upload) Click "Save and copy changes to all public communities" Then I get the error. Changes are not saved.

I am unable to update my user profile settings on Stack Overflow as I receive the following warning:     Oops! There was a problem updating your profile:   This email address is already registered. If it belongs to you, log in above or visit our account recovery page to get access to this account.   I have read through some of the similar questions about having to merge accounts but I only appear to have one account. I tried logging in with Facebook and standard email but both appear to link to the same user number.


I have this fiddle:    jQuery(function($) {     $(".parcelshop").click(function() {         $("#address_lastname").val(this.value); // Put the value into the Amount field     }); });  <input type="radio" class="parcelshop" name="data[shipping_address][address_firstname]" value="95621"> Click me  <input type="text" value="D1" id="address_lastname" name="data[shipping_address][address_lastname]">   And while it works in this controlled setup, I can't get it to work on my site.   I'm getting values from AJAX that populate a DIV - in this DIV I have a radio button for each result. I'm looking for a way to send the value of the user selected radio button to a input field, and I just can't get it to work.   Is it because the way AJAX works, that my javascript doesn't "see" the content of my AJAX output in the DIV?  Any pointers or help would be greatly appreciated.  Thanks

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


I've noticed that my /Users directory on OSX always gets changed to "rwxrwxrwx"  I'm not sure how this is being changed? Only just started happening  Could it be malware or such?

I use the Disk Utility to repair it. But the permissions change back after reboot.     Permissions differ on “private/etc/aliases”; should be lrwxr-xr-x ;   they are -rwxr-xr-x .    Permissions differ on “Users”; should be drwxr-xr-x ; they are drwxrwxrwx .    Permissions differ on “Users/Shared”; should be drwxrwxrwt ; they are drwxrwxrwx .   System: Mac OS X 10.9.3


I have yet to find a product or a question addressing this. The issue is quite simple. I am installing a tile floor in the bathroom, and the finished tile floor at the doorway will sit significantly lower than the adjacent hardwood floor. This is mainly due to the fact that it is two layers of hardwood / laminate flooring.  There are lots of products from schluter to address the reverse (tile is higher), and plenty of wood trim options for when the two floors are in the same plane. However, I have yet to find the proper trim type to transition from the tile UP to the hardwood. I assume this must exist. What type of trim is this. I would prefer a metal type trim, but am unsure what the options are. Does this exist? What is it referred to as and where would it be found?

I have ripped out some old carpet and am preparing to install a new solid hardwood floor myself.  In several places, the floor transitions to an existing tile floor.  The hardwood floor guys told me the best transition between the two is a T molding.  You simply leave a gap between the two floors, and then place down the T molding between the two floors, so it sits on both surfaces.  Sounds simple enough.  However, the height difference of the two floors is considerable, and the T molding does not sit flush.  What are my options?  Here is a diagram showing the dimensions.      NOTE:  Using the T molding is not a requirement, I could go some other route if there is a better option.


Let $f(x)=|x|^r$ on $B_1(0)$ real valued function.Where $B_1(0)$ is the unit ball in $\mathbb{R}^n$. I am trying to show that if $r>1-n$ f has a weak derivative.   ATTEMPT: I know from the definition of the weak derivative that I need to check whether there is a function $g:B_1(0)\rightarrow \mathbb{R}$ such that $$\int_{B_1(0)}f\phi'dx=-\int_{B_1(0)}g\phi dx,$$ for all test functions $\phi\in C_{c}^{\infty}(B_1(0))$. But since $x\in \mathbb{R}^n$, I dont know how to proceed. Please help.

Let $f(x)=|x|^r$ for a given real number $r$. Show that $f$ has first order weak derivatives on the unit ball $B_1(0)\subset \mathbb{R}^n$ provided that $r > 1-n$.  Does anyone have an idea on how to prove this?


I have a Array data structure right now, which contains 10  soldiers in my army.  They can setup initially in various formations  -  e.g.   o  o  o   o  o  o o  o  o  o   The user can move one of the soldier(currently selected) with the joystick.   o  o  o   o  o  o o  o  o            o   When he moves I want to automatically adjust the rest of the soldiers position so that they occupy equal areas in the scene, as well as still follow their orignal formation to some extent.  Somehow like this   How do I do this? What kind of algorithms should I look at? How should store my soldiers? which data structure?

For intentional reasons, certain units in the game I'm currently programming don't have any collision detection and response among each other.   This enables them to clutter right on top of each other. This is a wanted behavior, since there will be situations in the game when the player does want them to stack like that.  However, I want to make the process of uncluttering them easy for the player, so that they just have to press a hotkey or click some button on the screen and have the units disperse just enough so it's easy to select a group of them with the mouse (if they stand on top of each other one mouseclick selects all units).  How could I do this without running a brute force N^2 nearest neighbor search on all units?


I need some help about permission. I had a permission drwxrwxr-x but I try to change the permission with chmod 755 /folder/ and after that I receive permission drwxr-xr-x but I would like to change it back to drwxrwxr-x. Please can you help me with this?  Filip

Can you explain briefly the main concepts and command line tools used to manage file permissions?


I read an article about using commas for parenthesis and I want to make sure that I understand it properly. So can you guys tell me if I am using commas correctly in the following examples?  Examples:  My Mum, Jane Smith, is a nice lady.  Jake Mole, who is from Manchester, was arrested last night.  My daughter, Louise, is very helpful. ( Would this change to no commas if you had more than one daughter? For example if you had three daughters, how would you know which one is being talked about? )  My dog, which has one eye, is my best friend.  Those are my examples. So, am I using them right? If not, if you guys could explain to me how to properly use commas as parenthesis then that would be great. :)

When do you use commas and when do you use parentheses to provide more detail about something?  For example:   The suspect, Tom Wilson, is now being charged with murder. The suspect (Tom Wilson) is now being charged with murder. John Smith, a member of the jury, agreed with the verdict. John Smith (a member of the jury) agreed with the verdict. The first example, the one about the fox, is the more valid one. The first example (the one about the fox) is the more valid one.   I realize that the first example, the one that uses parentheses, is probably more valid in this case (if anyone has a better example, please include it), but when, if ever, would you favor parentheses?  Update: I realize that dashes are sometimes used for similar situations, so I'd appreciate information on these as well.  For example:   The children—who are wearing shoes—will go on the trip The children, who are wearing shoes, will go on the trip The children (who are wearing shoes) will go on the trip


Whenever I asked my grade school and college teachers why $\frac00$ is undefined, they would show me a graph of $\frac1x$ and point out the vertical asymptote at $0$, noting that "Since it approaches $-\infty$ from the left and $\infty$ on the right, it could be $-\infty$, $\infty$, or anything in between. So, we say it's undefined."  My question is, then, why isn't it $\Bbb R$, or even $\{\Bbb{R,C}\}$?

I came up some definitions I have sort of difficulty to distinguish. In parentheses are my questions.   $\dfrac {x}{0}$ is Impossible (  If it's impossible it can't have neither infinite solutions or even one. Nevertheless, both $1.$ and $2.$ are divided by zero, but only $2. $ has infinite solutions so as $1.$ has none solution, how and why ?) $\dfrac {0}{0}$ is Undefined and has infinite solutions. (How come one be Undefined and yet has infinite solutions ?) $\dfrac {0}{x}$ and $x \ne 0$, it's okay for me, no problem, but if someone else wants to add something about it, feel free to do it.


Why does the virtual image appear right on top of the object and not a little to the right, for example? Is it explained by some formula or just symmetry of the geometry?

What is the formula for Real vs Apparent Depth, when not looking perpendicular to the interface?   I know the formula $$\frac{\text{real depth}}{\text{apparent depth}}=n$$   but I'm not looking for this.


I'd like to know the difference between a library and an engine. I've searched some information and if I'm not wrong, an engine gives you more options and makes work easier than a library.   An engine can help you for example handling user input or handling collisions but I don't know how. I mean I've been using SFML and it has a function that detects collision between two rectangles. You can handle user input too.   How does an engine work? In what ways handling collisions for example is easier with an engine than with a library?

I am just starting out trying to learn to develop games. At first I thought C++ and OpenGL were the tools a beginner would start out to make a game, but quickly found out the OpenGL was just a API for graphics. Then I thought C++ and SFML were what I needed to learn to make a game, but found out the SFML was a media framework that could be used to make games but wasn't a game engine.  I don't want to use a software that does all the work for me, I want to code my own game, the way a game programmer would. I don't understand the difference between a IDE, framework, API, and a engine; What separates them from each other? Do some game programmers use the SFML framework, while other programmers use a game engine?


In this story, the characters live in a world with a wall that cannot be crossed. One day someone finds a way to get to the other side and discovers that as he's getting away from the wall and further into the other side, he's just coming back to his own world.

I am looking for a story about a tiny universe smaller than our Solar System. It has one star and one planet, and the planet's orbit is on the edge of universe. The planet's single face points to its sun at all times. The world has a very tall wall around its twilight circumference.  A civilization grows on the planet. The ruler of the civilization - curious about what is beyond the wall - commissions for a ladder to be built up the wall. He climbs the ladder and walks towards the darkness beyond the twilight atop the wall. He keeps walking and      comes back to his original location. Anything that goes beyond the wall at the edge of the universe is reflected back on itself.   I think it starts with a quote like this: "Many and strange are the universes that exist like bubbles in the foam along the river of time."


I have a large spreadsheet with a number of cells containing text that have a "*" character at the end. I would like to find and replace this character and delete it.  solution doesn't seem to work in Excel 2010.

I am trying to find and replace the * (star, or shift+8) character in a bunch of formulas in Excel 2007.  * of course matches the ENTIRE contents of the cell, which is not what I want.  How do I disable this behavior?


On , I have a few tags ignored ([a-song-of-ice-and-fire], [dune], and [fan-fiction]). I've set them to be completely hidden, not just grayed out. This works completely as it should.  However, I get  when looking at questions on tags with no questions in common with these that questions are being hidden, such as [led-zeppelin] and [moon]. This also happens when I search with queries about tags, such as [poe-dameron] -[star-wars], that don't apply to any questions with my hidden tags. These make no sense at all, and I believe they shouldn't be there.

The question  notes that if I try to search for a tag that does not exist, like say, , and I have ignored tags on that site, I get told that posts are being hidden because of those ignore preferences:  Hiding questions because of your Ignored Tags preferences for tags  This is ridiculous and it is misleading, and leaves the impression that if one searches for that tag and the offending ignored tag one would get results. Instead, one gets results like , which simply doesn't make sense:  (Note also that the [homework] tag is part of that query, and it is not in any way expected behaviour to have the results hide posts with the tag.) Compare that search, for example, with ,  which is much more reasonable. So, feature request: Don't tell me you're hiding posts when there are no posts to begin with. The purpose of the banner is to alert you to other possible queries that may yield results that are not being displayed. It is perfectly easy to tell when there are no results to show even with the ignore preferences turned off. If that is empty, simply don't show anything.


I have 3 pages with similar text content. For example  /hardwell/top-songs/ /hardwell/latest-songs/ /hardwell/similar-djs/  The main text content of the page is the biography on the top. It is the same for all the 3 pages. But the main content of the page is different, even though it is not text-heavy. Would google penalize me for this? How should one handle the SEO in such a case? In general how should SEO be dealt with in cases where the website is not text-heavy, eg. a music discovery website?

So I am building my website up, so far so good, only 2 categories and about 40 articles. Each category is different and several of the articles in each category are reviews.  My question is this...  I have 500 words of unique content on each review, and then I have around 300+ words of the exact same content across each review (different category different similar content)  The 300 words of similar content is things like..     Product contains eggs.      product contains milk      product doesn't have support      product company isn't active on social media.      product doesn't have email support.   Things like this, depending on the product and depending on how deep I dive into the reviews they range from 300+ words.  Is it okay to have these reviews with this point back to my category landing page? I mean they're ranking for separate products not the main keyword as my category landing page. Should I rework my strategy and just take out that similar content?


When you think that a feature request in a question should not be implemented (e.g. because you do not agree with the motivations provided) should you do either/both:   Downvote the question, so that by keeping a low score, it's clear it should not be implemented? Or Answer motivating why the feature request is not valid, or upvote an already present answer?

I have seen a few  here on Meta Stack Exchange that cover parts of this, but they are often too local, and none of them seem to cover all the relevant scenarios.  I will break it up into multiple parts in order to make this more specific:     When should I vote on a question:   What are the qualifications for a question to be deserving of being up-voted? When shouldn't I vote up on a question? What are the things that would cause a question to need to be down-voted?   How should I go about down-voting the question (do I wait a little while to give the OP a chance to change it, or do I down-vote it immediately)?  When shouldn't I vote down on a question?  When should I vote on an answer:   What are the qualifications for an answer to be deserving of being up-voted? When shouldn't I vote up on an answer? What are the thing that would cause an answer to need to be down-voted?   How should I go about down-voting the answer (do I wait a little while to give the OP a chance to change it, or do I down-vote it immediately)?  When shouldn't I vote down on an answer?  When should I vote on a comment:   While votes on comments do not affect reputation points, it might be useful to new users to know when to up-vote them.    It seems that a full, comprehensive list of these would be invaluable to new users looking to figure out how the voting system works, but this list seems to be missing from the meta site.


Problem: I have a table that list the person DOB.  I have a field (called Person_DOB) that I can use to grab the person DOB from the database. I would like to grab the person year they were born and compare it with the current year we are in.  Ex. 1988-09-26 00:00:00.000  I have a field that I can call that contains the DOB of the person. How can I covert that to a date and calculate their age using C#?  I have tried the following but it appears to not work:  <% int now = int.Parse(DateTime.Now.ToString("yyyyMMdd")); int dob = int.Parse("Person_DOB".ToString("yyyyMMdd")); int age = (now-dob) / 10000; Response.Write(age); %>   But I am getting invalid argument error. What am I doing wrong?

Given a DateTime representing a person's birthday, how do I calculate their age in years?


I am going through my weekly assignment of complex analysis but I am stuck at two points, since I don't understand a condition in the first case and what I'm being asked in the second one.  In the first part of the assignment I am given an entire function $f : \mathbb{C} \to \mathbb{C}$ such that  $$|f(z)| \leq \frac{1}{|\mathfrak{Im}(z)|}, \qquad \forall z \in \mathbb{C}$$   I have to prove that $f(z) = 0, \ \forall z \in \mathbb{C}$.  What is supposed to happen when $\mathfrak{Im}(z) = 0$? We are not working in $\overline{\mathbb{C}}$, so we don't assume that $f(z) = \infty$ for some $z \in \mathbb{C}$. How should I interpret this condition?  In another part of the assignment I am told to classify entire bi-periodic functions. I know what is meant by classification when one is  talking about e.g. manifolds or surfaces, but I am finding it hard to interpret in this case. At least this follows just from the definition:  Let $f$ be an entire bi-periodic function with periods $p_1, p_2 \in \mathbb{C}$, such that $p_1, p_2$ are $\mathbb{R}$-linear independent. Then we have  $$f(z + jp_1 + kp_2) = f(z) \qquad \forall z \in \mathbb{C}, \ \forall j, k \in \mathbb{Z_{\geq0}}$$    How should I categorize these functions?

Let $f(z)$ be an entire function such that $$|f(z)|<\frac{1}{|\text{Im}(z)|},\qquad z\in\Bbb C-\Bbb R.$$ The question asked me to prove that $f(z)=0$. At least looking at it, it really seems to have an application of Liouville's theorem lurking around somewhere, but I haven't found it.   My thoughts first led me to think about doing this by contradiction and using Picard's little theorem. So, I've considered a strip containing the real axis (say of width $2$ for simplicity). This will imply the complement maps into the unit disk, which implies that this strip has to map almost everywhere else on the complex plane. Now, on the imaginary axis, I know that $f(z)$ will vanish as $z\to\infty$, and this seems like it might be useful. I'm sort of under the impression $f(z)$ might have an essential singularity at $\infty$, which would mean $f(1/z)$ has an essential singularity at $0$. Either way, it of course can't have a pole at $\infty$ because of $f(z)$ vanishing on the imaginary axis, and if it is a removable singularity, it must be $0$, which still gives the solution. Therefore, I think it must have something to do with $f(z)$ having an essential singularity at $\infty$.   I was hoping to combine this with the above inequality and deduce a contradiction, but I haven't thought of one yet.   Any hints or suggestions? I'm studying for a prelim. exam, so this isn't homework.  Update: So, in the spirit of searching methods using the essential singularity at $z=0$, we have $$\left|f\left(\frac{1}{z}\right)\right|\leq\frac{1}{\left|\text{Im}\left(\frac{1}{z}\right)\right|}=\frac{|z|^2}{|y|}.$$ Thus, for $|y|>1$, we have $$\left|f\left(\frac{1}{z}\right)\right|<|y|\left|f\left(\frac{1}{z}\right)\right|<|z|^2.$$ Thus, if I can show that $|f(1/z)|$ is a polynomial, we'll know it can't have an essential singularity at the origin, concluding my proof.


I've read several great posts about traveling with 2 passports, specifically German and US. I'll be leaving Boston for Berlin with a layover in Iceland. In Iceland and Germany I will show my German passport. I know that when I am ready to leave Germany, I need to check in with my US passport and then go through exit customs showing my German passport.  My question is the following:  On my return flight from Munich to Boston, I have a layover in London. Which passport do I show them at customs upon entering? And which passport do I use in exit customs?  Thanks!

I am a citizen of two different countries, and have two passports.  How should I use my passports when traveling?


This book was about an astronaut studying an alien race. The alien village leader thinks he's a wizard or warlock, he also thinks the astronaut is a monster there to attack them. He uses ordinary things to make his magic and cause problems for the astronaut who's just there to study them.

I read this years ago. A scout in spherical advanced ship lands on a planet. Natives are friendly, but the shaman perceives competition, and sneaks into the craft and scatters potions on the controls, their acid eating into plastics and metals. He can be rescued at the other side of planet, but he has a deadline. Eventually all make airship and he makes it.


Just like a normal Minecraft player, I go onto servers and play with friends. But wait. When I join, my skin does not show up.  I am on a 1.8 server and nobody can see my skins. Please help someone.

I made a skin by using Skincraft and I exported it to minecraft.net. I chose my skin and uploaded it. At the top it says,      "Your skin has been changed! Please wait a few seconds for it to   update."   I went to Minecraft, clicked singleplayer and chose a random world at the top. I looked at my character, but it's still default. Multiplayer won't load for some reason. I don't know what I've done wrong!


How can I avoid the nested for-loops in the following Code and using the map-function instead for example?  import numpy as np  A = np.array([[1,2,3],[4,5,6],[7,8,9],[10,11,12]]) n = len(A[0]) B = np.zeros((n,n))  for i in range(n):     for j in range(n):         B[j,i] = min(A[:,i]/A[:,j])

How can I get the Cartesian product (every possible combination of values) from a group of lists?  Input:   somelists = [    [1, 2, 3],    ['a', 'b'],    [4, 5] ]   Desired output:  [(1, 'a', 4), (1, 'a', 5), (1, 'b', 4), (1, 'b', 5), (2, 'a', 4), (2, 'a', 5) ...]


I am in high school now and I want to get the basic idea of what relativity. Can anyone suggest me a book or website for it? I am also curious about the mathematics behind it. Is it possible for me to understand relativity in mathematical terms while still in high school? (Let's assume I know everything till Grade 12)

What are some good books for learning general relativity?


Is there any way to make flexible brackets around some text?  So I tried to use fancyvrb and got something like this:    \documentclass{article} \usepackage{fancyvrb} \usepackage{color}  \definecolor{darkblue}{rgb}{0.1,0.3,0.5}  \DefineVerbatimEnvironment%     {MyVerbatim}{Verbatim}     {gobble=0,label=\hspace{.85\textwidth},labelposition=all,      frame=single,framerule=3pt,framesep=5mm,rulecolor=\color{darkblue}}  \begin{document} \begin{minipage}{6cm} \begin{MyVerbatim} some text some text some  some text some text some  some text some text some  \end{MyVerbatim} \end{minipage} \hfill \end{document}   However, I am unhapy with it, because of the misuse of fancvrb.  I want to be able to define the thickness of the rule, the size of the corners or the spaces. A good candidate would be a package similar to dashedbox.  Any hint would be appreciated.

I am writing an Article in LaTeX.  Please suggest me how to create a highlight boxes like the ones shown below in LaTeX: