Total degree of a product of polynomials
Example of $\deg(fg)<\deg(f)+\deg(g)$
How can I configure the Ubuntu Dock to show windows only from the current workspace? How to solve configure: error: readline library not found? I have an Ubuntu 10.04 LTS server with a minimal install that I want to compile postgres on. With the minimal install the server did not have gcc so I had to do an apt-get install gcc but now I keep getting this error from the postgres ./configure.  configure: error: readline library not found   I can't seem to find the name of the package that contains the readline library. So I have two questions.   What is the name of the package that contains readline? Is there some way given the error message above for me to find the associated package from its standard name? There exist several implementations of the GBDT family of model such as:   GBM XGBoost LightGBM Catboost.    What are the mathematical differences between these different implementations?  Catboost seems to outperform the other implementations even by using only its default parameters according to , but it is still very slow.  My guess is that catboost doesn't use the dummified variables, so the weight given to each (categorical) variable is more balanced compared to the other implementations, so the high-cardinality variables don't have more weight than the others. It allows the weak categorical (with low cardinality) to enter to some trees, hence better performance. Other than that, I have no further explanation. I have a simple cylinder which is mirrored on both the X and Y axis.  When I scale it along the X axis, the two halves of the cylinder overlap, rather than scale as it would before the mirror modifier was applied:    I haven't used Blender in a while and I know this is a simple fix. Why is the $(\frac{1}{2},\frac{1}{2})$ representation of the Lorentz group realized as the vector space of Hermitian $2\times 2$ matrices? Can someone give me an example of a function $f: I\to \mathbb R$ which is uniform continuous but not Hölder continuous (for any $\alpha$)? Here $I$ is an interval. If $I$ is closed and bounded then we are essentially assuming that $f$ is merely continuous.   By saying that $f$ is not Hölder continuous for any $\alpha$, I mean for all $\alpha &gt;0$,   $$\sup_{x,y\in I, x\neq y} \frac{|f(x) - f(y)|}{|x-y|^\alpha} = \infty.$$  That is, I need to find a function $f$ so that for all $\alpha$ and $M&gt;0$, there are $x, y\in I$ so that   $$ \frac{|f(x) - f(y)|}{|x-y|^\alpha} \ge M.$$  I know that $f(x) = x^\alpha$ are $\alpha$-Hölder continuous. Thus, in some sense, I am looking for $f$ which are worst than the functions $x^\alpha$ for all $\alpha &gt;0$. I can't read beta sites' chat logos! Here, you try:  If it weren't for the text shadow, it might as well be entirely invisible...  The cause is a CSS rule lurking in the transcripts for beta sites only:  #transcript-logo {   background: none repeat scroll 0 0 #273A5D; }   The problem is the #273A5D - a bluish colour not dissimilar to that used for the site name in the beta theme. Disabling that rule yields the much more manageable  I'll admit it is a little hard to read the "beta" in that shot. But if you had to choose which part was readable, wouldn't you choose the bit that tells you the name of the site?  Edit: It happens when actually in a chat room too! How do I send SMS from PC through Android Phone or to Android Phone? I'm looking for an app that will let me type text messages on my PC and send the SMSs directly from the PC through my phone, or save the messages to the phone for later use.  I'm basically looking at something like Nokia PC Suite's equivalent.  EDIT:  Google Voice is only for US, doesn't work in India at least, and also defeats the purpose (it will go through the internet, why, when it's possible through the usb cable/modem/wifi). DesktopSMS is a good program, but kept crashing, for some reason. PDANet worked for me. But I liked the tiny . It's weird, and I had to change the bluecove library jar file for Windows 7 x64, but it's compact (a concern for me). 10 hour layover in Moscow Russia, do I need a transit visa? On June 29th 2015, I will be traveling for the first time to Italy from USA. I will have a 10 hour layover in Moscow Russia. My question is, do I need a visa to visit the city? To all the 'sed' doctors out there:  How can you get 'sed' to extract a regular expression it has matched in a  line?   In other words words, I want just the string corresponding to the regular  expression with all the non-matching characters from the containing line stripped away.  I tried using the back-reference feature like below  regular expression to be isolated           gets `inserted`                here                     |                v    sed -n 's/.*\( \).*/\1/p    this works for some expressions like   sed -n 's/.*\(CONFIG_[a-zA-Z0-9_]*\).*/\1/p    which neatly extracts all macro names starting with 'CONFIG_ ....' ( found in some '*.h' file ) and prints them all out line by line             CONFIG_AT91_GPIO           CONFIG_DRIVER_AT91EMAC                    .                    .              CONFIG_USB_ATMEL           CONFIG_USB_OHCI_NEW                    .                  e.t.c.    BUT the above breaks down for something like    sed -n 's/.*\([0-9][0-9]*\).*/\1/p    this always returns single digits like                    7                  9                  .                  .                    6   rather than extracting a contiguous number field such as.                 8908078               89670890                    .                  .                    .                23019                     .                e.t.c.     P.S.: I would be grateful to feedback on how this is achieved in 'sed'.        I know how to do this with 'grep' and 'awk'       I would like to find out if my - albeit limited - understanding of        'sed' has holes in it and if there is way to do this in 'sed' which I       have simply overlooked. I need to round the edges of this object.  The bottom edges are going to be rounded in conjunction with another object, so, I guess, this should be left out right now.  I tried using the bevel tool (and a bevel modifier) on an edge (series of Blender edges), but I got the problems you see on the images. When selecting all edges, the bevel doesn't know any limit and isn't applied symmetrically.  When selecting only the edges shown (or only the other ones), I can't proceed with the rest of the bevel, and strange little artifacts appear.  FYI: The top surface is derived from an icosphere.    Without the subdivision shown above, a stair comes into existence (bad):    Whole object: Exclude folder using `find` command I'm using the find command on a Mac to search for a folder called test1. Now test1 folder could be present in the .Trash folder also. How do I exclude the .Trash folder from getting reported in search results or basically any folder I wish to exclude?  $ find $HOME  -name test1 -type d /Users/theuser/.Trash/test1 /Users/theuser/test1  /Users/theuser/Downloads/test1    I want the result to be just  /Users/theuser/test1 /Users/theuser/Downloads/test1    I used grep:  find $HOME  -name test1 -type d | grep -v '.Trash'    to filter out the .Trash result, but I'm interested in knowing if using find alone achieves the same results. Scrolling has stopped working in chat There is  with this exact same prompt which got several down-votes for not showing  their work.  So I'll show what work I've got.  I know being a harmonic function implies satisfying the Mean Value Property, thus what I thought I'd do is consider two arbitrary points in $\mathbb{C}$ and prove that:  $$|u(z) - u(w)|=|\frac{1}{2\pi}\int_0^{2\pi}u(z - re^{i\theta})d\theta - \frac{1}{2\pi}\int_0^{2\pi}u(w - te^{i\theta})d\theta| $$ $$= |\frac{1}{2\pi}\int_0^{2\pi}u(z - re^{i\theta}) - u(w - te^{i\theta})d\theta|$$  Now what I wan't to do is take r and t to infinity and prove this integral goes to zero, but I can't figure out how to do that.  I've used the fact that my harmonic function u is defined on all of $\mathbb{C}$ in taking t and r to infinity but I still need to use the fact that it's bounded.  I also read through the proof of Liouville's Theorem, given as an answer in that other post, which seems intuitively correct but rather un-rigorous.  It actually says that the value in the center of a ball is equal to the average over the ball's volume.  I imagine this can be proven from the average over the boundary since the average over the boundary will not change as you continuously shrink the boundary down to its center. This however would require the difference of two surface integrals, or is there a simpler way?   I was also considering using the Maximum Modulus Principle somehow but I haven't found a way yet.  I've probably made this way more complicated than it has to be, hopefully someone can help me, thanks! =].  Edit: Ok after thinking some more about the accepted answer in that other post, I've decided what I need to do is look at the canonical holomorphic function whose real part is my harmonic function u, and prove that holomorphic function is bounded.  From there I can prove that since it's entire and bounded that it's constant, and from there prove that then its real part must be constant.  So could someone talk a bit about the construction of this canonical holomorphic function? Disabling IPv6 on Mint and Debian How does one disable IPv6 completely (for all interfaces, resp. for the whole machine?  Keep in mind, I don't want any kind of GUI solution.    OS in question:   Linux Mint 18.x Cinnamon 64-bit GNU/Linux Debian 9.x Cinnamon 64-bit Postgres : Relation does not exist error I'm trying to get Intel and Nvidia graphics card working together with two monitors. One monitor should use the Intel card and the other the Nvidia card. Of course, I want to use only one keyboard and one mouse to switch between both screens. Bumblebee didn't work for me.  I don't want to use the xserver-xorg-video-all package because I need the Nvidia card for gaming and I can't use only one graphics card because I need one for KVM virtualisation and the other one for my Linux desktop  So I tried to install the drivers and to configure the Xserver manually. The Nvidia driver is working and I get a video output. But I don't get a video output with the Intel card.  I followed   The config files: I have an independent variable called "quality"; this variable has 3 modalities of response (bad quality; medium quality; high quality). I want to introduce this independent variable into my multiple linear regression. When I have a binary independent variable (dummy variable, I can code 0 / 1) it is easy to introduce it into a multiple linear regression model.  But with 3 modalities of response, I have tried to code this variable like this :  Bad quality      Medium quality      High quality       0                1                  0      1                0                  0      0                0                  1      0                1                  0   But there is a problem when I try to do my multiple linear regression: the modality Medium quality gives me NA:    Coefficients: (1 not defined because of singularities)    How can I code this variable "quality" with 3 modalities? Do I have to create a variable as a factor (factor in R) but then can I introduce this factor in a multiple linear regression? "Writ large", "Writ small", and others I have seen this used with other words besides "large" and "small".  What other words can be used? Can this structure be used more generally with other adjectives? When should titles like "captain" or "admiral" be capitalized? Please excuse the contrived example below, but I am wondering if this example is properly capitalised? I'm assuming that capitals are used when addressing someone directly, but lower case is used elsewhere. Can someone give some rules on this?      The captain walked into the room.    "Hi, Captain," said the admiral.   "Hi, Sir," replied the captain.   "Call me Admiral."   "Hi Admiral."   The captain and admiral stepped forward.   "Prime Minister, this is Captain Jones," said Admiral Brown.   "Pleased to meet you," said the prime minister.