How do I check whether a package from multiverse is installed?
Find what packages are installed from a repository
Assume that $X$ and $Y$ are independent random variables with $X \sim \exp(\lambda)$ and $Y \sim \exp(\mu)$. It is impossible to obtain direct observations of $X$ and $Y$. Instead, we observe the random variables $Z$ and $W$, where $Z = \min\{X,Y\}$ and $W =1$ if $Z=X$ and $W=0$ if $Z=Y$.  How to find the joint distribution of $Z$ and $W$? Cloning an SD card onto a larger SD card I'm using Ubuntu 12.04. I have an old 4GB SD card, and have just bought a new 16GB SD card. I would like to copy everything from my old 4GB SD card onto the new 16GB SD card. I was afraid that the usual copy-and-paste trick would miss out something, so I wanted to clone the old 4GB SD card onto the 16GB SD card. I used the dd command in a shell, following instructions in .  This worked with one small caveat. The new SD card now appeared to be 4GB. I later found out this is because the primary partition on the 16GB SD card has now shrunk to 4GB. I have solved this problem, and I think I understand it. However, my question now is, how do I clone my old 4GB SD card onto my new 16GB SD card without making the primary partition on the 16GB SD card shrink to 4GB? Why are neural networks becoming deeper, but not wider? In recent years, convolutional neural networks (or perhaps deep neural networks in general) have become deeper and deeper, with state-of-the-art networks going from 7 layers () to 1000 layers ( in the space of 4 years. The reason behind the boost in performance from a deeper network, is that a more complex, non-linear function can be learned. Given sufficient training data, this enables the networks to more easily discriminate between different classes.  However, the trend seems to not have followed with the number of parameters in each layer. For example, the number of feature maps in the convolutional layers, or the number of nodes in the fully-connected layers, has remained roughly the same and is still relatively small in magnitude, despite the large increase in the number of layers. From my intuition though, it would seem that increasing the number of parameters per layer would give each layer a richer source of data from which to learn its non-linear function; but this idea seems to have been overlooked in favour of simply adding more layers, each with a small number of parameters.  So whilst networks have become "deeper", they have not become "wider". Why is this? Monochromatic squares in a colored plane Installing Broadcom Wireless Drivers I'm having serious problems installing the Broadcom drivers for Ubuntu. It worked perfectly on my previous version, but now, it is impossible.   What are the steps to install Broadcom wireless drivers for a BCM43xx card?  I'm a user with no advance knowledge in Linux, so I would need clear explanations on how to make, compile, etc.    lspci -vnn | grep Network showed:   Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b]      iwconfig showed:  lo        no wireless extensions. eth0      no wireless extensions.   NOTE: Answer below is updated every time new information is added and confirmed working. Is it recommended I enter the US only in the city where my university is situated? I'm an Indian student who will be beginning graduate school in the US. Before the start of my program, I want to visit my relatives who live in Atlanta, Georgia. Is it recommended that I enter US in the state my university is located in (Tucson) and then fly to visit my relatives, or is it okay to enter Atlanta? I ask the question with the current political climate in the US in mind.  Is it enough if I have a ticket to Tucson as proof that I am only planning a brief stay in Atlanta?  EDIT: I updated the question to include the cities I'm referring to. Both these cities have international airports. See , page 2: the internal logic diagram for the MM74HC138.    The diagram shows logic inverters with bubbles at the input or at the output. Is there an actual difference between them? ExitCodes bigger than 255, possible? If yes, on which operating system, shell or whatever?  Consider the following java program (I'm using java just as an example, any language would be good for this question, which is more about operation systems):  public class ExitCode {     public static void main(String args[]) {         System.exit(Integer.parseInt(args[0]));     } }   Running it on Linux and bash, it returns always values less equal 255, e.g. (echo $? prints the exit code of the previous executed command)  &gt; java ExitCode 2; echo $? 2  &gt; java ExitCode 128; echo $? 128  &gt; java ExitCode 255; echo $? 255  &gt; java ExitCode 256; echo $? 0  &gt; java ExitCode 65536; echo $? 0     EDITED: the (only, so far) answer below fully  explain what happens on UNIXes. I'm still wondering about other OSes. Using Illustrator CS6 to create shape out of multiple paths How to serve static files in Flask In De Broglie's Explanation for Bohr's Quantization Condition, why do we not use 2πr = n λ/2, why do we use 2πr = n λ? In de Broglie's explanation for Bohr's quantization condition, why do we not use $2\pi r = n\lambda/2$, why do we use $2\pi r = n\lambda$?  We know that in waves on strings, for standing waves creation in a string between two rigid supports, we use "Length of String" $ = n \lambda/2$. Why do we not use a similar concept here? Should I buy a Canon 55-250mm lens or 70-300mm for my Rebel T3i? I have the basic 18-55mm lens that came with my camera but I need a next step up that's not too expensive.   What are the most common types of photos shot with either lenses? Or what is each lens best for? I'm working on a large c++ system that is has been in development for a few years now. As part of an effort to improve the quality of the existing code we engaged on a large long-term refactoring project.  Do you know a good tool that can help me write unit tests in C++? Maybe something similar to Junit or Nunit?  Can anyone give some good advice on the methodology of writing unit tests for modules that were written without unit testing in mind? If column matches another file, print every line with match (awk/grep) I’m taking two input files, one with certain ID numbers, and another with a large list of ID numbers and additional columns. The latter file contains multiple lines for each ID number and I need to extract all lines that match an ID from the first file. Those lines then must be printed in a new file.  Edit 1: Replaced sample files with excerpts from actual  Edit 2: Removed extra spaces that were in excerpt, but not actual file. Files likely need to be sanitized in some way, but how is unclear.  file1:  AT1G56430 AT3G55190 AT3G22880   file2:  AT1G01010|GO:0043090|RCA AT1G56430|GO:0010233|IGI  AT1G56430|GO:0009555|IGI  AT1G56430|GO:0030418|IGI   expected output  AT1G56430|GO:0010233|IGI  AT1G56430|GO:0009555|IGI  AT1G56430|GO:0030418|IGI   [[  I have tried:  awk -F'|' 'NR==FNR{c[$1$2]++;next};c[$1$2] &gt; 0' file1 file2 &gt; output.txt   and:  grep -Ff file2 file1 &gt; output.txt   I’m aware that there are many somewhat similar questions posted in these forums and others. However, these don’t mention how the output is handled… nor do they mention duplicates. I’ve tried solutions from 4 of them, have been messing with this for many hours and keep getting the same problem: a blank output file.   I’m new to awk and I greatly appreciate the help. Sorry if this is a simple problem with syntax etc; please let me know. Thanks for the help. How does quantization solve the ultraviolet catastrophe? Is it possible to win in Don't Starve? I would like to know if it's possible to win in Don't Starve? Or is it just the matter of how long until you die? Let $(A,+,\cdot)$ be a unity ring with the property that if $x \in A$ and $x^2=0$ then $x=0$. Consider the set $M=\{a\in A | a^3=a\}$. Prove that:      a) $2a\in Z(A)$, $\forall a\in M$, where $Z(A)$ denotes the centre of the ring $A$;   b) $ab=ba$, $\forall a,b\in M$.   My attempts revolved around the fact that an idempotent element in a reduced ring is central. So, since for $a\in M$ we have that $(a^2)^2=a^2$, it follows that $a^2\in Z(A)$, $\forall a\in M$. The next thing I wanted to use in order to solve a) was that $Z(A)$ is a subring of $A$, so if I had proved that $(a+1)^2 \in Z(A)$, $\forall a\in M$, then we would have reached the desired conclusion. However, I couldn't prove this and I honestly doubt that it is true. Another idea that I had was to prove that $M$ is a subring of $A$. Of course, this didn't work out because I cannot even prove that $M$ is closed under addition. Again, I don't know if this is true and it most likely isn't. As for b), I think that a) should be of use, but I don't know how. It is a well-known problem that a ring with $x^3=x$ for any $x$ in that ring is commutative, but since $(M,+,\cdot)$ is almost definitely not a ring, this doesn't help. EDIT: Is there any chance that this question is simply wrong? I tended to believe this before asking it here too, but since nobody has made any progress on it until now I am even more inclined to think so. Prove there are k consecutive non-squarefree integers So, I've got a question for class that asks me to prove the existence of arbitrarily long runs of consecutive integers where $\mu(n)$ is zero.   I've started the proof, but I need a bit of help midway through.  Assume there exists a run of length n, which we currently assume is the longest possible chain.  If we induct on n, we can assume there is a run of the form $m_1p_1^2, m_2p_2^2, ..., m_np_n^2$ (where each of the $p_i$ are prime).  If I add $M =  lcm(m_1p_1^2, m_2p_2^2, ..., m_np_n^2)$ to each number, I get another run of length n.  So here's where the issue starts. When I talked to my advisor about it, he referenced a theorem where there exists a prime $p$ congruent to $1\ mod\ M$.  I am unfamiliar with this theorem, so I'm not sure how to use this information. Any chance I can get some help? Or else is there a simpler way to go about this problem? Can I use a Mac Mini as an Airplay audio receiver? I don't have an AppleTV (yet), but I do have a Mac Mini hooked up to some decent speakers.  Is there something I can run on it, so that it acts like an Airplay audio receiver?  (Video support isn't important to me.) This question is related to  and explores an apparent inconsistency, given only the Harry Potter movies as source material.  The Hogwarts Express line seems to have an inconsistent existence between magical (invisible to ordinary humans aka muggles) and non-magical (muggle) realms; platform 9-3/4 is clearly hidden from muggles, but in Chamber of Secrets, when Harry and Ron take the car (in the muggle world) to catch up to the train, they make no explicit crossing into a magical realm, suggesting that the train is traveling the muggle world despite its departure from a magical platform.  In which realm (magical or muggle) does the Hogwarts Express exist? How is this apparent inconsistency resolved?