I'm new to Ubuntu I have installed Ubuntu on my computer everything seems to work fine but Wi-Fi. I was wondering if anyone know how can I install Wi-Fi drivers for Asus Rampage IV Black edition?  I ran this command in terminal lspci -vvnn | grep 14e4, it gave me the chipset of my wifi:      Broadcom Corporation BCM4352 802.11ac wireless network Adapter [14e4:43b1] (rev 03).    Any idea how can I get the driver from here? Thanks

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.


I dual boot Ubuntu and Windows 10 but I accidentally formatted the Windows partition which contains all my backup. How can I recover data on that partition?

About two weeks ago I had a problem with my PC that my brother wrote a question about at .  I still haven't solved the problem, so my PC is unusable now.  Now I think that it would be simpler to re-install both Win7 & Ubuntu than repair them, but there're some data on their partitions. I want to recover this data.  These partitions are not mountable for some reason. I don't know why.  sudo fdisk -l about the problematic partitions:     Device    Boot      Start         End      Blocks   Id  System /dev/sda1            2048     147912703    73955328   83 Linux /dev/sdb2            206848   174079999    86936576    7  HPFS/NTFS/exFAT   And in GParted:      And the error of the mount command:  Failed to mount '/dev/sdb2': Invalid argument The device '/dev/sdb2' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?   And the exact same message for /dev/sda1  How can I recover my data from those HDDs?  EDIT     I have tried to specify the type of the drive:  $ sudo mount -t ext4 /dev/sda1 /olddisk mount: wrong fs type, bad option, bad superblock on /dev/sda1,        missing codepage or helper program, or other error        In some cases useful info is found in syslog - try        dmesg | tail  or so $ sudo mount -t ntfs /dev/sdb2 /olddisk NTFS signature is missing. Failed to mount '/dev/sdb2': Invalid argument The device '/dev/sdb2' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?   EDIT     sudo ntfsfix /dev/sdb2 returns:  Mounting volume... NTFS signature is missing. FAILED Attempting to correct errors... NTFS signature is missing. FAILED Failed to startup volume: Invalid argument NTFS signature is missing. Trying the alternate boot sector Unrecoverable error Volume is corrupt. You should run chkdsk.


This is fantasy, not SF. It was a novel, alone in its own book, but it was a rather small book. And I read it in the 60's, I am sure. (I understand that the tag "fantasy" should not be used for a question to identify a fantasy story, only on questions on the genre itself)  It starts rather small scale, a girl (I think) who could control insects, bees if I remember properly, and uses them to pester another child (probably a boy) who has ways to get rid of the bees. Then it starts escalating.  In the end it becomes an epic fight between the forces of Good and those of Evil. I remember that the Zoroastrian deities Ahura Mazda and Ahriman are mentioned (I got this spelling in Wikipedia right now, the spelling in the book might well have been different but I am sure they were the ones from Zoroastrian religion)

I'm not sure I recall enough of this story for a good identification, and the below is definitely out of story order, but...  The POV character goes to his home town and finds it different. He later finds that he's trapped in the town; there are two young people who turn out later on to be ... avatars ... of Ormazd and Ahriman, and the town is a battleground; what he is seeing of the town is Ahriman's effect on the town, and he turns out to have some limited ability to see the original town, which is more-or-less Ormazd's version of reality. In the end, Ahriman's avatar is destroyed, and the town restored.  I read this in the '80s or earlier; it was part of my father's collection, and the book was showing its age; I think it more likely to be the '60s rather than the '50s, and was probably by a prominent name in SF, but not one of the Masters.


Suppose A & B are sets of reals.Then is it true that inf{A+B}$\leq$inf{A}+inf{B}.I consider all the cases like A contains all positive and B contains all positive,then alternate positive and negative combinations, and it seems true to me.Is it true?

A+B={a+b} I proved that the set A+B is bounded below. Now I'm stuck on how to prove that inf(A+B) = infA + infB


The Ubundu screen resolution 640*480 and not able to chnage.  I installed the virtual machine in windows 10

I've recently installed Ubuntu on Oracle's Virtualbox.  Now I want to install the guest additions.  I started up my Ubuntu guest OS, clicked "Devices" and chose "Install Guest Additions". Nothing happened, and I don't see the CD icon on my desktop.  How can I make this work?


I am working on an exporter, for Babylon.JS, for a version of Blender which does not have the internal render (developing in 2.79 though).  For previous versions of the exporter, if a material with nodes was encountered, baking was just done right in the exporter.  Babylon.JS supports Physically Based Rendering (PBR), and materials similar for the internal render, so I want to try to map things when possible.  Leads me to, how do I know where to start walking the tree.  I could just run through the nodes checking for an output material like:  for shader in material.node_tree.nodes:     shaderName = shader.bl_idname     if shaderName == 'ShaderNodeOutputMaterial':         # got it   Think there must be a better way.  Though it might be stupid, you can add more than one of that type, yet the UI knows which is the one hooked up.  Another way might look for a node which has no outputs, but I can see the same issue.

From a given node tree, what is the most reliable way to get the end node being used for output, if any?  My current approach is to check for the correct output type for the tree (OUTPUT_MATERIAL, OUTPUT_WORLD...) and for is_active_output:  nodes = node_tree.nodes  for n in nodes:     if n.type == 'OUTPUT_WORLD' and n.is_active_output:         return n  return None   However, I see no guarantee that there is only one node with is_active_output (I can set this to True in multiple nodes).  The ShaderNodeTree has an active_input field, but the value is -1.


Is it possible to play splitscreen online in starwars battlefront on the ps4. I've tried to invite my friends to the party, and then play, but that doesn't work. Please respond to me if you know

How many players can play split-screen, and what game modes are (or aren't) available?   How many players can play local co-op? How many players can play local multiplayer? How many players can play online multiplayer from a single console?


Every Cayley-Dickson algebra can be viewed as a $(+,-,*,0,1)$ algebra. The reals and the complexes share the same equational identities. The quaternions have a subset of the equational identities, because they lose commutativity of multiplication. The octonions lose associativity, and the sedenions lose even more. Is the sedenions truly the last stop. Do all further Cayley-Dickson algebras have the same equational identities in that signature as the sedenions. This question is different from the tagged question, because I didn't see an answer for whether there are any equational identities that the sedenions have that any higher Cayley-Dickson algebras don't. I know that the sedenions are a power associative algebra.

In the construction of types of numbers, we have the following sequence:  $$\mathbb{R} \subset \mathbb{C} \subset \mathbb{H} \subset \mathbb{O} \subset \mathbb{S}$$  or:  $$2^0 \mathrm{-ions} \subset 2^1 \mathrm{-ions} \subset 2^2 \mathrm{-ions} \subset 2^3 \mathrm{-ions} \subset 2^4 \mathrm{-ions} $$  or:  "Reals" $\subset$ "Complex" $\subset$ "Quaternions" $\subset$ "Octonions" $\subset$ "Sedenions"  With the following "properties":   From $\mathbb{R}$ to $\mathbb{C}$ you gain "algebraic-closure"-ness (but you throw away ordering). From $\mathbb{C}$ to $\mathbb{H}$ we throw away commutativity. From $\mathbb{H}$ to $\mathbb{O}$ we throw away associativity. From $\mathbb{O}$ to $\mathbb{S}$ we throw away multiplicative normedness.   The question is, what lies on the right side of $\mathbb{S}$, and what do you lose when you go from $\mathbb{S}$ to one of these objects ?


Suppose λ ∈ [0, 1]. Suppose also F and G are distribution functions. Prove that (1 − λ)F + λG is also a distribution function.  I know a function a a distribution if  the random variable X is less than or equal to x of function  and if λ equals something in between 0 and 1 and including them would result just in a multiple of F and G expect in cases when λ is 0 and G becomes zero,   what does multiplying a distribution function by a constant do to it?

Let $F,G$ be cumulative distributions functions. I need to find a necessary and sufficient condition for $\alpha$ such that $(1-\alpha)F+\alpha G$ is also a cumulative distribution function.   I have found that a sufficient condition is $0 \leq \alpha \leq 1 $, but I'm not sure wether it is a necessity. I'm struggling with proving that given $\alpha >1$ or $\alpha<0$ ,  $(1-\alpha) F+\alpha G$ is not monotonic.  Any ideas?


I am having problems compiling a Beamer-presentation w/math symbols when running as non-administrator under Win7-64. (I use TeXStudio 2.10.8 with a complete install of MiKTeX 2.9.) To give an example, the following works well as an administrator:  \documentclass{beamer}   \begin{document}   \begin{frame}       Test: $Y_t$   \end{frame}   \end{document}    By contrast, when running as a non-administrator, I need to comment out the math for compilation to work:  \documentclass{beamer}   \begin{document}   \begin{frame}       Test: %$Y_t$   \end{frame}   \end{document}     Compilation under the article-class w/math works well, so the problem seems to be Beamer-related. The messages I get when trying to compile as non-administrator below. Anyone any suggestion for how I can solve my problem?  From messages:     Process started: pdflatex.exe -synctex=1 -interaction=nonstopmode "test".tex      Sorry, but miktex-makemf did not succeed for the following reason: The mathkerncmssi source file could not be found. The log file hopefully contains the information to get MiKTeX going again: C:/Users/sucarrat/AppData/Local/MiKTeX/2.9/miktex/log/miktex-makemf.log You may want to visit the MiKTeX project page, if you need help.      Sorry, but miktex-makepk did not succeed for the following reason: PK font mathkerncmssi8 could not be created. The log file hopefully contains the information to get MiKTeX going again: C:/Users/sucarrat/AppData/Local/MiKTeX/2.9/miktex/log/miktex-makepk.log You may want to visit the MiKTeX project page, if you need help.   Process exited with error(s)  From log:     Font shape OT1/cmss/m/n' in size <4> not available(Font) size <5> substituted   pdflatex.exe (file pdftex.map): cannot open font map file]\tf@nav=\write6\openout6 =test.nav'.   Size substitutions with differences(Font) up to 1.0pt have occurred.      pdflatex.exe (file pdftex.map): cannot open font map file]\tf@nav=\write6\openout6 = `test.nav'.      Size substitutions with differences(Font) up to 1.0pt have occurred.

My original question was:   The answer that seems suitable to my cause is to install cm-super. I did that (using package manager [winxp 32 bit, MikTex installation 2.9 recently updated]). But still the command  \usepackage{cm-super}    yields an error.  User H Cavendish suggested to run updmap-sys, but I am not sure about how to do that on WinXP.   2011 November 04 edit: I made it sure that I have installed 'cm-super' - but still get the same error:   I have also tried updating the file name databases - but no avail.


I searched for every tag possible on an egg (item) but I didn't find anything special to get an egg that will never spawn a chicken.  these are all the visible tags on an item.egg + the command I used to get them (I runned that command when I dropped the egg on the ground)    so does anyone know how to /give or get an egg without the chance to spawn a chicken?

I'm using retextured snowballs and eggs for the different paintballs for two teams in a paintball map, so I can't replace the eggs with snowballs.  I have tried using /gamerule doMobSpawning false, but that still allows the chickens to spawn. I have also tried using /tp @e[type=Chicken] 0 0 0 on a repeating command block to quietly remove the chicken, but there's still a very noticeable frame where the chicken is visible. /effect @e[type=Chicken] minecraft:invisibility 10 1 false isn't fast enough, either.  I'm not using any plugins or mods.  tl;dr Without snowballs, how can I stop chickens from appearing for even a single frame.


I just upgraded to macOS Sierra and the pop-up prevalence is driving me crazy.  I am using a 2011 Macbook Air with only 256GB SSD space, and have consistently had 10GB or less storage remaining since almost immediately after purchasing.  I am getting pop-ups saying "You only have 10.27 GB of storage left, Save space by optimizing storage". They are similar in nature to the pop-ups described in these two questions:  and   However, neither of these questions have answers to their [slightly] different pop-ups.  Is there any way to disable these pop-ups entirely? It is not possible for me to free up more storage on anything longer than an extremely short term basis, so that is not an acceptable solution.

After upgrading to macOS Sierra, I'm getting the notification that "Your disk is almost full. Save space by optimizing storage.":    The options appear to be to store my files in iCloud, automatically delete files, or manually delete files:    My problem/irritation is that I have 80GB free of my 440GB volume.  The question: is there a way to silence this notification in a (semi-)permanent fashion, or to change the threshold it uses for the notification?


apt-get update is failing on India location. Its not able to reach out to in.archive.ubuntu.com. Below is the error : # apt-get update  Hit:1 http://dl.google.com/linux/chrome/deb stable InRelease Hit:2 http://security.ubuntu.com/ubuntu focal-security InRelease                   Err:3 http://in.archive.ubuntu.com/ubuntu focal InRelease                            Cannot initiate the connection to in.archive.ubuntu.com:80 (2403:8940:ffff::f). - connect (101: Network is unreachable) Could not connect to in.archive.ubuntu.com:80 (103.97.84.254), connection timed out Err:4 http://in.archive.ubuntu.com/ubuntu focal-updates InRelease   Cannot initiate the connection to in.archive.ubuntu.com:80 (2403:8940:ffff::f). - connect (101: Network is unreachable) Err:5 http://in.archive.ubuntu.com/ubuntu focal-backports InRelease   Cannot initiate the connection to in.archive.ubuntu.com:80 (2403:8940:ffff::f). - connect (101: Network is unreachable) Reading package lists... Done W: Failed to fetch http://in.archive.ubuntu.com/ubuntu/dists/focal/InRelease  Cannot initiate the connection to in.archive.ubuntu.com:80 (2403:8940:ffff::f). - connect (101: Network is unreachable) Could not connect to in.archive.ubuntu.com:80 (103.97.84.254), connection timed out W: Failed to fetch http://in.archive.ubuntu.com/ubuntu/dists/focal-updates/InRelease  Cannot initiate the connection to in.archive.ubuntu.com:80 (2403:8940:ffff::f). - connect (101: Network is unreachable) W: Failed to fetch http://in.archive.ubuntu.com/ubuntu/dists/focal-backports/InRelease  Cannot initiate the connection to in.archive.ubuntu.com:80 (2403:8940:ffff::f). - connect (101: Network is unreachable) W: Some index files failed to download. They have been ignored, or old ones used instead.   Can someone please suggest / help here.

I just installed a fresh version of Ubuntu 19.10 today, and the first thing I decided to do was to install GNU Screen, using sudo apt-get install screen. my output was: Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package screen  I figured the package archives were not quite updated as it was a clean install so I tried sudo apt-get update. This is what I got: Get:1 http://security.ubuntu.com/ubuntu eoan-security InRelease [97.5 kB]       Err:2 http://au.archive.ubuntu.com/ubuntu eoan InRelease   Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) Could not connect to au.archive.ubuntu.com:80 (202.158.214.106), connection timed out Err:3 http://au.archive.ubuntu.com/ubuntu eoan-updates InRelease      Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) Err:4 http://au.archive.ubuntu.com/ubuntu eoan-backports InRelease   Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) Fetched 97.5 kB in 31s (3,106 B/s) Reading package lists... Done Building dependency tree        Reading state information... Done All packages are up to date. W: Failed to fetch http://au.archive.ubuntu.com/ubuntu/dists/eoan/InRelease  Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) Could not connect to au.archive.ubuntu.com:80 (202.158.214.106), connection timed out W: Failed to fetch http://au.archive.ubuntu.com/ubuntu/dists/eoan-updates/InRelease  Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) W: Failed to fetch http://au.archive.ubuntu.com/ubuntu/dists/eoan-backports/InRelease  Cannot initiate the connection to au.archive.ubuntu.com:80 (2001:388:30bc:cafe::beef). - connect (101: Network is unreachable) W: Some index files failed to download. They have been ignored, or old ones used instead.  I'm really not sure why it would be doing this, other than maybe some first-use hiccups? The computer is definitely connected to the internet, as I am writing this from that machine, and I have tried running the commands after rebooting and it still gives the errors. I can't seem to be able to connect to au.archive.ubuntu.com at all. ping au.archive.ubuntu.com just sits there without a response. If anyone could help, that would be great! If any extra information is required I'd be happy to edit it into the question.


What is the highest ability score possible for a player character (including magic items and temporary effects)?

Can I increase an ability score over 30 with an item such as a Manual of Bodily Health?     [After reading] this book... your Constitution score increases by 2, as does your maximum for that score.


In Quantum Mechanics, we know that given a potential we can solve the eigen value problem to find out the energy eigen values and eigen functions. Now suppose in an experiment we have information only about the energy levels of a system and not the potential. Can we do the reverse and find out the nature of the Potential of the System uniquely?

A typical problem in quantum mechanics is to calculate the spectrum that corresponds to a given potential.    Is there a one to one correspondence between the potential and its spectrum?  If the answer to the previous question is yes, then given the spectrum, is there a systematic way to calculate the corresponding potential?


Now that the tag editing privilege has been removed, tag edits go through the Suggested Edits queue.  The problem is that users are suggesting edits that are pure tag edits. I'm sure most are in good faith and not trying to game the system, but there are usually other problems with the post. The suggested action is to either reject as "Too Minor" or to improve the edit.  The problem is that I don't want to award the reputation when there are other problems with the post. I want the user to learn that minor edits are discouraged. However, sometimes, their tag edit is really good. So, I want to keep that tag edit, but I don't want to award the reputation. The only thing I can do is look for something else that can be changed (like removing a "Thanks"), fixing it, and unchecking the "Suggested Edit was helpful" box.  However, , that soon becomes a problem. Especially with users who click through to earn badges with no regards to quality!  I also feel that having an edit rejected due to my "improvement" can discourage users. That's not what we want! We want users to improve the site through editing!  We need a way to approve tag edits without discouraging users by rejecting. The only way to due this currently is to approve them. The flaw with that, as mentioned above, is that the user doesn't learn.  I propose we keep tag edits going through the queue, but either don't award reputation, or only award one rep point.  Who's with me?!

A certain user just got 42 reputation from removing the  from a bunch of questions and doing nothing else. This seems very wrong, because the questions had other things wrong with them, but people were accepting the edits. I rejected them, but since I am only one person, they were accepted anyway.  I feel that for purely tag-based edits, you should not get as much rep for editing as you do for actually editing a question. I think it should either be taken away entirely, or reduced to a much lower rate, say 1 rep point per every 2 questions.


I need an account system added to my website as a plugin to all of my HTML pages. The account system plugin needs to,register new users, log in current users, remove users who want to disconnect service, and manipulate all of these things via database on my web server.  However, I do not know how to program in the PHP language or create and manipulate MySQL databases. I want a program that can create and manipulate the MySQL database automatically for my website and handle also PHP calls automatically.  Are there any open source freeware programs out there that i can use? If so what are the names of these freeware?

This is a general, community wiki  question to address non-specific "I need a CMS or Wiki that does x, y, and z..." questions.  If your question was closed as a duplicate of this question and you feel that the information provided here does not provide a sufficient answer, please open a discussion on .    I have a list of features that I want for my website's Content Management System (CMS) - where can I find a [free] script that includes all of them?


I was running 14.04 on my Intel Atom processor based netbook. However, when I upgraded to Ubuntu 16.04, the netbook stopped working properly.  I have now understood that the 1 GB of RAM is not adequate to run 16.04. I therefore want to roll back to 14.04.  Is there an easier way of roll back or, do I need to download 14.04 and install over the existing system?

I can update my Ubuntu to the new LTS version. As you can think, its not a highly important server since I run 13.10 (not a LTS version). Anyway - I actually want to upgrade my server, but would like to be able to revert this upgrade.   I would be able to reinstall Ubuntu 13.10 and overwrite it with my backup. But I want to know if there is a more comfortable way to do this. TBH I guess theres no command as undo-release-upgrade but I thought it would be worth to ask for it.  This is my current daily backup script  tar cvpzf $backup_file --exclude=/proc --exclude=/lost+found --exclude=$backup_file --exclude=/mnt --exclude=/sys --exclude=/media --exclude=/tmp /


I have recently started Andrew NG's Machine Learning course on Coursera and I came across this cost function which is:    Why does the error in the cost function need to be squared? If its purpose is to eliminate the negative sign in the error then why don't we simply use the absolute function?

I'm just getting started with some machine learning, and until now I have been dealing with linear regression over one variable.  I have learnt that there is a hypothesis, which is:  $h_\theta(x)=\theta_0+\theta_1x$  To find out good values for the parameters $\theta_0$ and $\theta_1$ we want to minimize the difference between the calculated result and the actual result of our test data. So we subtract  $h_\theta(x^{(i)})-y^{(i)}$  for all $i$ from $1$ to $m$. Hence we calculate the sum over this difference and then calculate the average by multiplying the sum by $\frac{1}{m}$. So far, so good. This would result in:  $\frac{1}{m}\sum_{i=1}^mh_\theta(x^{(i)})-y^{(i)}$  But this is not what has been suggested. Instead the course suggests to take the square value of the difference, and to multiply by $\frac{1}{2m}$. So the formula is:  $\frac{1}{2m}\sum_{i=1}^m(h_\theta(x^{(i)})-y^{(i)})^2$  Why is that? Why do we use the square function here, and why do we multiply by $\frac{1}{2m}$ instead of $\frac{1}{m}$?


I have tried root and ratio test but they were inconclusive. thank you very much

$$ \sum_{n=1}^\infty \frac{n!e^n}{n^n} $$ Where $e$ is Euler's number.  Recently on calculus class we were covering convergence tests and my group got stuck with this infinite series. Our calculus teacher told us that it diverges but he doesn't see any elementary way or simple test to prove it. He told us something about Euler's Gamma function and said that he knows it diverges because of Stirling's formula but this is not quite our level yet.  I tried to think about it myself but I established only that this  is some kind of an edge case. We could generalize the problem to series of $\frac{n!a^n}{n^n}$. Then, from the ratio test we know that it converges for $a <e$ and diverges for $a>e$. For $a=e$ the test is inconclusive. I've also tried to compare it with various divergent series, but nothing worked...  Does anybody have any idea for a simple solution?


I have a HP laptop with pre installed Windows 8, only about 12 months old, I hate it and now something has gone wrong with it and it wont reset as it says the files are missing, I have gone over to using Chromebook now, but want to use the laptop for something, how do I remove Windows and install Ubuntu in its place? I tried to install already but it won't disable the safe boot function. I'm not all that knowledgeable, but will give it a go as not much to lose as the damn thing is unusable now.

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


I came upon this phrase in a Hilary Mantel's novel (Wolf Hall): "John Williamson is needed in the Cromwell business"  Why is the possessive form not being used for "Cromwell business".

I would like to know what the rule is to explain why we do not use the genitive construction hotel's room. Instead, we say "a hotel room".  Other examples:      a hospital bed   a bike stand   Would it suffice to ask "What kind of..."?


Every couple days I have a "new" alert in my inbox, if I go looking at it I find some messages from February, click it away and then the recent messages appear (no new ones though). The screenshot below is taken on Area51, it also regularly happens on Arqade.  I just noticed that I did have a real new alert, that then got "read" because I looked at the old ones.

I'm having an odd and inconsistent problem where certain inbox notifications are re-appearing within my inbox every few days, even though the date/time for the notification is a week, two weeks, a month, two months or even three months ago. Unfortunately my screenshot didn't take so I don't have a screenshot at this time. The messages I'm getting within the inbox that are repeating though are posts that have been migrated, moderator elections, and other non-answer related items.  Usually a page refresh or clicking on the inbox notification badge, opening the inbox dropdown, and clicking outside of the dropdown clears the messages out of the timeline. Yet every week or so they all re-appear again.    Update I finally was able to capture a screenshot. This was taken this morning at 8:06am. Even though I have an inbox notification of "7", you can see that the "newest" inbox notification dates from May 22nd and the other 6 "new" notifications are from as far back as Feb 2014.


Example:  I have the words red, blue, yellow, green. The term enclosing all those words would be "color".  For computer, phone, laptop, that word may be electronic devices.   On top of most words, you have the word "thing".  In short, what do you call a word enclosing a specific group of words?  Right now, I am searching for a word enclosing words such as "beehive", "birdbox", and other spaces humans created for animals to live in, most often as a product.  Thanks.

Bats and rats are mammals. 1 and 2 are positive integers. Oaks and maples are trees. Carrots and cake are food.   I seek a word to describe this, the process of finding a concept that encompasses several given concepts. Is there such a word?


I really like how, in the winter bash, there are hats. They are pretty cool and actually encourage me to get badges, something I didn't care about before. I think there should be something like this, but all year round, to encourage people to get badges. Badges, to me, seem currently pretty useless and I never want to get any because...there is no good reason to. Hats: well, hats are just awesome

the hats get put back in their boxes on January 4th   Do the hats affect me in any way after the 4th? A badge or something in my profile about how many I unlocked?  Edit: Can I request some form of persistence... please?


I'm trying to increase the frame rate of my game from 60FPS to 100 FPS because of reasons. But i can't seem to get it higher than 60 frames.  is the count I'm using. I can slow down the frame rate by setting TargetElapsedTime = new TimeSpan(0, 0, 0, 0, 16);   to a higher value, but settings it lower won't increase the frame rate, according to the counter. Anyone have any idea what's going on?

I created a . It works great: It displays 60.0 fps normally. If I artificially slow down the game loop, it drops.  My 'game' at the moment is a single keyboard-controlled sprite, so it should be possible to render more frequently than 60 frames a second.  I figured turning off vertical synchronization would increase the FPS cap:  public Game1() {     _graphics = new GraphicsDeviceManager(this)                     {                         PreferredBackBufferWidth = WindowWidth,                         PreferredBackBufferHeight = WindowHeight,                         SynchronizeWithVerticalRetrace = false,                     };     _graphics.ApplyChanges();     Content.RootDirectory = "Content"; }   However, even though the above code seems like it should turn off vsync, it doesn't seem to be. Is there something wrong with my constructor, or perhaps my FPS calculations? Or is there something else that may be limiting the frame count?


I am confused at $\infty$ in a lot of ways. First, we sometimes say that ${1\over 0}=\infty$. That gives us these confusing calculations.$${1\over0}=\infty$$ $$1=0*\infty$$ $$2=(0*2)*\infty$$ $$2=0*\infty$$ $$1=2$$ But certainly, this is not true. $1\ne 2$. What is happening? Another confusion: let's say $x=x+1$. This is never true. But with $x=\infty$, it works. Third confusion: let's say $2x=x$. Subtracting both sides by $x$ gives $x=0$. But what about $\infty$? Fourth confusion: $x-x=0$ is always true, but not for $\infty$. $\infty-\infty$ is undefined. What is actually happening??! Any help will be very appreciated.

I would say $\infty - \infty=0$ because even though $\infty$ is an undetermined number, $\infty = \infty$. So $\infty-\infty=0$.


I would appreciate it if you could give me a few hints as to how I should go about solving this problem.  Suppose $T:\mathfrak{X}\rightarrow \mathfrak{Y}$ is bounded. Show that $\left\|T\right\|=\inf\{K\in\mathbb{R}:\left\|Tx\right\|_{\mathfrak{Y}}\leq K\left\|x\right\|_{\mathfrak{X}} \}$.  I know that $T$ is bounded if $\left\|T\right\|:=\sup\{\left\|Tx\right\|_{\mathfrak{Y}}:\left\|x\right\|_{\mathfrak{X}}\leq 1 \}$. How can I go from $\sup$ to $\inf$?  Thanks in advance

How do you prove that these four definitions of the operator norm are equivalent? $$\begin{align*} \lVert A\rVert_{\mathrm{op}} &= \inf\{ c\;\colon\; \lVert Av\rVert\leq c\lVert v\rVert \text{ for all }v\in V\}\\ &=\sup\{ \lVert Av\rVert\;\colon\; v\in V\text{ with }\lVert v\rVert\leq 1\}\\ &=\sup\{\lVert Av\rVert\;\colon\; v\in V\text{ with }\lVert v\rVert = 1 \}\\ &=\sup\left\{ \frac{\lVert Av\rVert}{\lVert v\rVert}\;\colon\; v\in V\text{ with }v\neq 0\right\}. \end{align*}$$


I have just started studying Ajax for making my own chat application using MySQL, PHP, JavaScript and Ajax. I have almost made my application but the problem is that I have used setInterval so my box in which chat log is displayed it is fetched from the database every second and displayed,and this is inefficient.  Rather I want that the database is accessed only when there is some change in the database ,that is, when a user sends a message and the database is changed then only the database is fetched by other users message box.

Of course I am aware of Ajax, but the problem with Ajax is that the browser should poll the server frequently to find whether there is new data. This increases server load.  Is there any better method (even using Ajax) other than polling the server frequently?


The definition of the SI base unit "metre" [1] doesn't seem to rule out explicitly that a certain value of "length, in meters" could be attributed to a pair of ends which are rigid to each other, but not at rest to each other.  Consider, therefore, two such ends, $A$ and $B$, which both find constant but unequal ping durations between each other, i.e. in the notation of [2]$\! {\,}^{(\ast)}$:  $[ \, A \, B \, A \, ] \ne [ \, B \, A \, B \, ]$.  Is there a value of "length, in meters" attributable to this pair of ends, $A$ and $B$ ?  If so, what is that value?, i.e. if the SI definition allowed to express the value of "the lenght $AB$" as "$x \, \text{m}$", for some positive real number $x$,  then how should $x$ be expressed in terms of the two (given) unequal ping duration values $[ \, A \, B \, A \, ]$ and $[ \, B \, A \, B \, ]$, and the SI base unit "second" ("$ \text{s}$")? (Is perhaps:  "$x := \left( \frac{[ \, A \, B \, A \, ]}{2 \, \text{s}} + \frac{[ \, B \, A \, B \, ]}{2 \, \text{s}} \right) \times \frac{299 \, 792 \, 458}{2}$"? Or perhaps:  "$x := \sqrt{ \frac{[ \, A \, B \, A \, ]}{2 \, \text{s}} \times \frac{[ \, B \, A \, B \, ]}{2 \, \text{s}} } \times 299 \, 792 \, 458$"? ...)  References: [1] SI brochure (8th edition, 2006), Section 2.1.1.1;  ("The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second."). Together with "the mise en pratique of the definition of the metre";    [2] J.L.Synge, "Relativity. The general Theory", North-Holland, 1960; p.409: " [...] light signals passing between a source $0$ and mirrors $1$, $2$, [...] Trip-times such as $[ \, 0 \, 1 \, 0 \, ]$ [...] are measureable [...]"  $(\ast$: Suggestions for more standard and/or expressive notation for ping durations are welcome.$)$

Considering the definition of the SI unit of "length" [1] and [2 (" method a.")] I'm missing any requirements about the two "ends" of the required "path travelled by light" being "at rest to each other", or at least "rigid to each other".  Are such requirements perhaps presumed to be understood implicitly?  Accordingly, if some particular pair of "ends", $A$ and $B$, in some particular trial, were characterized as having been a certain "lenght of $x \, \text{m}$ apart from each other", where "$x$" is some particular positive real number and "$\text{m}$" denotes the SI base unit "metre", is it then understood:   that ends $A$ and $B$ had observed exchanging signal pings between each other; and not only once for each trial, but for any of their signal indications throughout a sufficiently extended trial?, that for any two (distinct) signal indications $A_J$ and $A_K$ of end $A$ during this trial the corresponding ping durations of end $A$ were equal to each other: $\tau_A[ \,_J, \,_{\circledR}^{B \circledR AJ} ] = \tau_A[ \,_K, \,_{\circledR}^{B \circledR AK} ]$ ?, that for any two (distinct) signal indications $B_P$ and $B_Q$ of end $B$ during this trial the corresponding ping durations of end $B$ were equal to each other: $\tau_B[ \,_P, \,_{\circledR}^{A \circledR BP} ] = \tau_B[ \,_Q, \,_{\circledR}^{A \circledR BQ} ]$ ?, and that for any signal indications $A_J$ of end $A$ and any signal indication $B_P$ of end $B$ during this trial the corresponding ping durations were equal to each other: $\tau_A[ \,_J, \,_{\circledR}^{B \circledR AJ} ] = \tau_B[ \,_P, \,_{\circledR}^{A \circledR BP} ] = \frac{2 x}{c} \text{m} $ ?.   References: [1] SI brochure (8th edition, 2006), Section 2.1.1.1;  ("The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.").  [2] "the mise en pratique of the definition of the metre";


Suppose I was able to create a simulation of the universe (I can't, but suppose I could). And in said universe, intelligent and sentient life evolved.  What would happen if I "unplugged" this simulation, or simply altered it and killed all the sentient life. Would I be killing these beings, or would they have simply not been alive?  In short, can anything existing in a computer program be alive?, and if say, we were living in a computer simulation, could the beings that created us consider us to be alive?

Say, for the sake of this question,  is real. Are we then hurting "persons"/conscious beings in "our simulations" - video games - when we fight them? Why (not)? If so, is this unethical? Think for example about shooting an alien in the game No Man's Sky.  Edit/answer on the comment of Joseph Weissman: My reasoning is like this:   It is unethical to harm a person (with a person being everything that has ). By the simulation hypothesis (assuming it's true), everything around us (everything that we know of), is simulated. By 1 and 2, all persons we know of are simulated. So it's unethical to harm the simulated persons around us. A game is a simulation just like we are in a simulation, so the game has simulated persons. Therefore -  - it's unethical to harm the persons in a video game.   I know that the premises - besides the simulation hypothesis itself - are debatable, but that's the reason I asked the question in the first place.  I was also thinking that the characters in the video game differ because they have far less to no intelligence, that much of it is scripted. But I neither have a proof that we ourselves aren't scripted, with free will being an illusion. Also, how intelligent does a character in a simulation/video game has to be to have personhood then? I think this is a case of the .  Just to be sure, please note that this question is not about whether the simulation hypothesis is true or how likely it is to be true. It is about (one of the) consequences if the simulation hypothesis is true. It's also not a question about violence in games in general.


I am trying to implement a singly linked list that stores multiple types of item. So I came across templates, but when I tried running the following code, the compiler gives me several linking errors (LNK 2019: unresolved external symbol). I haven't really done anything yet and can't figure out what went wrong. Can anyone please point out my mistake??  singlylinkedlist.h  template <class Item> class SinglyLinkedList { public:     SinglyLinkedList();     ~SinglyLinkedList();  private:     template <class I>     struct Node {         I item;         Node<I> *next;     };     Node<Item> *head;  };   singlylinkedlist.cpp  #include "singlylinkedlist.h"  template <class Item> SinglyLinkedList<Item>::SinglyLinkedList() {     head = NULL; }   main.cpp  #include <iostream> #include "singlylinkedlist.h"  using namespace std;  int main() {     SinglyLinkedList<string> list; }

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


I am reading a book on Operator Algebras and at a point the authors seem to make the following implication:     Let $A$ be a $C^*$-algebra and $\{a_i\}_{i=1}^n$ a linearly independent subset. If $(u_\lambda)_{\lambda\in\Lambda}$ is an approximate unit for $A$, there exists a $\lambda_0\in\Lambda$ such that $\{a_iu_{\lambda_0}\}_{i=1}^n$ is also linearly independent.   I have doubt about the validity of this, or at least that it is immediate. My work is the following:  There is an elementary lemma in functional analysis (mostly used to show that all norms over finite dimensions are equivalent) that says that "whenever $\{a_i\}_{i=1}^n\subset X$ are linearly independent in a normed space, then there is a constant $C>0$ such that for all $(x_i)_{i=1}^n\subset\mathbb{C}$ it is $\|\sum_{i=1}^nx_ia_i\|\geq C\cdot\sum_{i=1}^n|x_i|$.  Let $C>0$ be the constant for $\{a_i\}_{i=1}^n$. Suppose that for each $\lambda\in\Lambda$ we have complex numbers $\{x_i^\lambda\}_{i=1}^n$ such that $\sum_{i=1}^nx_i^\lambda a_iu_\lambda=0$. Suppose furthermore that $\{x_i^\lambda\}_{i,\lambda}$ is bounded, say by a constant $M>0$.   Let $\varepsilon>0$ and pick $\lambda_0\in\Lambda$ such that for all $\lambda\geq\lambda_0$ it is $\|\sum_{i=1}^na_iu_\lambda-\sum_{i=1}^na_i\|<\varepsilon C/M$. Then for such $\lambda$ it is $$\sum_{i=1}^n|x_i^\lambda|\leq \frac{1}{C}\|\sum_{i=1}^nx_i^\lambda a_i\|=\frac{1}{C}\|\sum_{i=1}^nx_i^\lambda a_i-\sum_{i=1}^nx_i^\lambda a_iu_\lambda\|\leq \frac{M}{C}\|\sum_{i=1}^na_i-\sum_{i=1}^na_iu_\lambda\|<\varepsilon.$$ So we obtain that for all $i$ it is $x_i^\lambda\xrightarrow[\lambda\in\Lambda]{}0$. But that's the best I can get, and, don't forget I have added a hypothesis (the boundedness of the coefficients).  Am I missing out the obvious?  refers to the same thing (the same book too). OP answers to himself, but It doesn't make any sense to me, they pick an index large enough such that an approximation holds for all scalars? This seems wrong to me.

Let $B$ be a C*-algebra and $\{b_{i}\}_{i=1}^{n}\subset B$ be linearly independent. If we take $\{f_{k}\}\subset B$ which is approximate units, then can we find a large $k$, such that $\{b_{1}f_{k}, b_{2}f_{k},...,b_{n}f_{k}\}$ is a linearly independent set?


How can I prove that there is no $x\in \mathbb{Z}[\sqrt{-5}]$ such that $x\cdot (2+\sqrt{5}i)= 3$ ?

In the ring $\mathbb{Z}[i]\space$, which of the following elements belongs to the principal ideal $(3+i)$? (a) $1+8i$  (b) $1+5i$  (c) $1+6i$  (d) $1+7i$


The Annals of Mathematics is published bimonthly by the Department of Mathematics at  Princeton University. I would like to know what font they use for "ANNALS OF MATHEMATICS" on the cover page. If there isn't an exact one, is there anything similar? :

Is it possible to identify the font used in a specific document/picture?  Answers to this question should identify:   Possible methods to do this (perhaps one answer per method) and adequately describe how to use it (as opposed to merely stating it); Ways of finding the identified fonts, if possible (free or not); and Any prerequisites associated with the method used, if required (for example, "In order to use method X, your document has to be in format Y").   This question is meant as an FAQ, based on an . Its aim is to facilitate the community with the general procedures involved in font identification. Similar cases are solved on a per-usage basis on 's  tag.


Let's say I have L2 regularization in ridge regression:  How would I go about giving a formal mathematical proof that  I know that the larger the lambda the smaller the L2 norm. But, I don't know how to give a mathematical proof

I have understood how ridge regression shrinks coefficients towards zero geometrically. Moreover I know how to prove that in the special "Orthonormal Case," but I am confused how that works in the general case via "Spectral decomposition."


I'm looking for the name of a paradox I found on the internet some time ago. I'm not entirely sure about the formulation which involved a few mathematical expressions, but this is how I recall it in plain language:     The probability of selecting a particular point on a circle when choosing randomly (with continuous distribution) is zero everywhere.      An event with zero probability is impossible.      Let's draw a circle and select a point on it randomly.      Now an impossible event has already happened and it is still impossible.   What is the name of paradoxical statements similar to this one, and what is the canonical explanation?

I read a comment under :     There are plenty of events that can occur that have zero probability.   This reminds me that I have seen similar saying before elsewhere, and have never been able to make sense out of it. So I was wondering    if zero probability and impossibility mean the same? if an event with zero probability doesn't mean that the event is impossible to occur, how probability theory represents/describes impossibility?   Thanks and regards!


The following arguments are valid for docker command:  docker ps -f"status=exited" --format 'table {{.Names}}' #output: # jovial_hellman   # modest_blackwell   So I have created this script   docker-ps-exited  #!/bin/bash # show exited docker processes docker ps -f"status=exited" $@   But when I try to add the rest of the arguments in the console it fails:  docker-ps-exited --format 'table {{.Names}}' # ERROR OUTPUT: # "docker ps" accepts no arguments. # See 'docker ps --help'. #  # Usage:  docker ps [OPTIONS]    Why the script fails passing the arguments correctly? How should I write it in order to be able to accept any arguments I pass at the end?

The old advice used to be to double-quote any expression involving a $VARIABLE, at least if one wanted it to be interpreted by the shell as one single item, otherwise, any spaces in the content of $VARIABLE would throw off the shell.  I understand, however, that in more recent versions of shells, double-quoting is no longer always needed (at least for the purpose described above).  For instance, in bash:  % FOO='bar baz' % [ $FOO = 'bar baz' ] && echo OK bash: [: too many arguments % [[ $FOO = 'bar baz' ]] && echo OK OK % touch 'bar baz' % ls $FOO ls: cannot access bar: No such file or directory ls: cannot access baz: No such file or directory   In zsh, on the other hand, the same three commands succeed.  Therefore, based on this experiment, it seems that, in bash, one can omit the double quotes inside [[ ... ]], but not inside [ ... ] nor in command-line arguments, whereas, in zsh, the double quotes may be omitted in all these cases.  But inferring general rules from anecdotal examples like the above is a chancy proposition.  It would be nice to see a summary of when double-quoting is necessary.  I'm primarily interested in zsh, bash, and /bin/sh.


In the following code snippet:  testtest2   I want 'test' to occupy 250 pixels without changing the size of the text. In other words, I would like the word 'test' to print, followed by however may pixels is required to reach a total width of 250 pixels (test + blank space) then the word 'test2' to print afterwards. What CSS do I use to achieve this?

Within an unordered list:
 The lazy dog.

AND The lazy cat.

OR The active goldfish.
   Adding a class or style attribute is permitted but padding the text and adding or changing tags is not allowed.  The page is rendering with Courier New.  Goal is to have text after span lined up.      The lazy dog. AND The lazy cat. OR  The active goldfish.   Justification of the "OR" is unimportant.  The lazy animal text may be wrapped in an additional element but I'll have to double check.


Can someone explain the  in layman's terms, I'm having some difficulty understanding it?

In the past few days I've become increasingly intrigued by the QHE, mainly thanks to very interesting questions and answers that have appeared here. Unfortunately, I am as of yet very confused by all the (seemingly disparate) stuff I learned.  First, here are some random points that I've been able to gather   I(nteger)QHE occurs due to the presence of Landau levels IQHE is an embodiment of topological order and the states are characterized by the Chern number that tells us about topologically inequivalent Hamiltonians defined on the Brillouin zone IQHE requires negligible electron-electron interations and so is dependent on the presence of impurities that shield from Coulomb force F(ractional)QHE occurs because of formation of anyons. In this case Coulomb interaction can't be neglected but it turns out an effective non-interacting description emerges with particles obeying parastatistics and having fractional charge FQHE has again something to do with topology, TQFT, Chern-Simons theory, braiding groups and lots of other stuff FQHE has something to do with hierarchy states   So, here are the questions        Most importantly, do these points make sense? Please correct any mistakes I made and/or fill in other important observations   How do explanations 1. and 2. of IQHE come together? Landau quantization only talks about electron states while topological picture doesn't mention them at all (they should be replaced by global topological states that are stable w.r.t. perturbations)   How do explanations 4., 5. and 6. relate together   Is there any accessible introductory literature into these matters?   Do IQHE and FQHE have anything (besides last three letters) in common so that e.g. IQHE can be treated as a special case? My understanding (based on 3.) is that this is not the case but several points hint into opposite direction. That's also why I ask about both QHE in a single question


As 20.04.1 is released, I wanted to upgrade from 18.04.4 LTS to 20.04.1 on my Dell Precision 5530 workstation. However there seems to be no update yet: $ sudo do-release-upgrade Checking for a new Ubuntu release There is no development version of an LTS available. To upgrade to the latest non-LTS develoment release  set Prompt=normal in /etc/update-manager/release-upgrades.  I'm trying to understand what do-release-upgrade does and while checking /etc/update-manager/meta-release, I saw URI_LTS which is probably the address being checked. It's currently set to  and this address is resolved into a single IP address: 91.189.95.15 -- which seems to be in UK and belongs to Canonical. (so it's not a server near me which is out of date?) The file doesn't include focal as of now. So my question is.. Am I missing something or this file is not yet updated and that's the reason I'm not seeing the update? What's the procedure for this? Edit 1: In another post, I learned about DEBUG_UPDATE_MANAGER=1 do-release-upgrade and made sure that the file is not yet updated. But why? $ sudo DEBUG_UPDATE_MANAGER=1 do-release-upgrade                                                                                ⏎  Checking for a new Ubuntu release MetaRelease.__init__() useDevel=False useProposed=False /etc/update-manager/meta-release: https://changelogs.ubuntu.com/meta-release  /etc/update-manager/meta-release: https://changelogs.ubuntu.com/meta-release-lts  /etc/update-manager/meta-release: -development  /etc/update-manager/meta-release: -proposed  metarelease-uri: https://changelogs.ubuntu.com/meta-release-lts MetaRelease.download() reading file '/var/lib/update-manager/meta-release-lts' have self.metarelease_information MetaRelease.parse() current dist name: 'bionic' found distro name: 'dapper' found distro name: 'hardy' found distro name: 'lucid' found distro name: 'precise' found distro name: 'trusty' found distro name: 'xenial' found distro name: 'bionic' There is no development version of an LTS available. To upgrade to the latest non-LTS develoment release  set Prompt=normal in /etc/update-manager/release-upgrades.

I understand that the first point release of Ubuntu 18.04, namely 18.04.1 is now available and that my system should now offer it as an update.  My current OS version is 16.04.5 LTS. In System Settings/Software and Updates I have set 'Notify me of a new Ubuntu version' to 'For long term support versions'. I have tried both the main server and the server for United Kingdom, neither offers an update when Software Updater is clicked or via the Ubuntu Software icon.  Can anyone please tell me why I don't get the option of updating to 18.04?  Edit:  I don't remember the details exactly, but I think that my last LTS point release update was offered automatically a lot sooner after the published release date than where we are now with 18.04.1.  Edit 10th August  It appears that there has been some problem with the update process and that it should be fixed next week, see:    Edit 14th August 18.04.1 LTS now available from UK server,


I want to completely delete everything I have with Stack Exchange, but I can only delete the accounts on specific communities. The main stackexchange.com account doesn't seem to have an option to delete it. I just see this:   (No, the "Update profile info" doesn't show any more options)

If one has an account on any of the SE sites (Stack Overflow, Super User etc.), in order to delete their account, they can do so from their profile page. Numerous similar questions have been asked and answerers are always directed to this page:    However, even after one has deleted all their accounts and one is not a participant of any of the communities, one continues to be logged in when they visit www.stackexchange.com. Now, if one clicks on any of the communities (Stack Overflow, Meta etc.), they are first asked to join. But how does one delete their master account, so that instead of being asked to join, they are first asked to log in?


Apologies if this is a really basic question, but what is the physical interpretation of the Poisson bracket in classical mechanics? In particular, how should one interpret the relation between the canonical phase space coordinates, $$\lbrace q^{i}, p_{j} \rbrace_{PB}~=~\delta^{i}_{j} $$ I understand that there is a 1-to-1 correspondence between these and the commutation relations in quantum mechanics in the classical limit,  but in classical mechanics all observables, such as position and momentum commute,  so I'm confused as to how to interpret the above relation?

In quantum mechanics, when two observables commute, it implies that the two can be measured simultaneously without perturbing each other's measurement results. Or in other words, the uncertainty in their measurements are not coupled.   But in classical mechanics, in an analogous way we have the Poisson brackets instead, where when two functions/variables of the systems have a vanishing Poisson bracket with each other, we say they are in "involution".  I understand that when a variable $j$ has a vanishing Poisson bracket with the Hamiltonian of the system, means that $j$ is a constant of motion, conserved in time. But for the general case:      If the Poisson bracket of $f$ and $g$ vanishes ($\{f,g\} = 0$), then $f$ and $g$ are said to be in involution.    What does the above mean physically? Is it in some sense related to measurement results as it is with commutators in QM, meaning two variables in involution are completely independent of each other? Finally, is there a simple classical example, where one can see 2 observables are in involution, but 2 other (same system) may not be (i.e. counter-example for involution)? I think it would help better understand what in "involution" means.


I just installed Ubuntu twice and I get a GRUB Error.   I think it's because of the mount point. Since I put it at the root of the HDD. Where do I put it?   Is it / or /boot? Or am I completely wrong?

I have installed Ubuntu 12.10 in a Western Digital external hard drive (320GB). This is a complete installation, not a live USB.  When I plug it in my HP desktop I go to the BIOS settings and boot off the hard drive, everything work perfectly as it should. Now this works on every single computer and laptop in my house (all HP), except for ONE. My HP ProBook 4530s.  When I select to boot of the USB I get the message:  error: attempt to read or write outside of disk 'hd0'   Now, I have removed the hard drive from my laptop and the external drive is the ONLY drive plugged in. Below is a screenshot of the message on the screen. After the message I navigate to ls / (as shown below):    After here I try to acces other folders under ls /, for example, I try to go to ls /boot to get to the grub folder. Then I get the same message as before: as shown below:    grub rescue> ls /boot  error: attempt to read or write outside of disk 'hd0' grub rescue> _   The only folders I can access without getting the message again are /home, /run and /usr.   So how do I:   Boot Ubuntu from GRUB2 (this screen) manually Set to automatically boot Ubuntu If possible an explanation for this problem   Thanks!


My daughter is 5 months old and is an amazing night sleeper who is able to settle herself to sleep during the night she goes to bed at 8 and will not wake until 430-5 o clock for a feed then wakes up at about 730. What I would like advice on is getting her to sleep longer during the day. She will show signs of being tired yawning rubbing eyes  multiple times during the day but when I put her down she will either take forever to settle or will sleep for no longer than 45 mins at a time. I would like to know how to get her to sleep for longer periods of time . I’m afraid this might be because she is overtired because she couldn’t get into a deeper sleep. Help please any tips on how to improve her napping habits would be greatly appreciated!

My daughter is 4 1/2 months old and she only naps for 30-45 minutes at a time. She wakes up happy, but she is tired again after a little over an hour.   I know some babies are naturally short nappers. But there have been times where she will sleep two hours or longer if I'm holding her (which I have stopped doing altogether for her naps).   I have a short nap routine and I use a sound machine during her naps.   Any advice? Thanks in advance!   -- She takes 4 or 5 naps per day. She is only awake 1.5 hours before she begins showing sleep signs.


I'm working in modules with webpack and in order to avoid creating variables in the global scope, I did this Revealing Module Pattern: function establishArrays() {      let globalVar = (function () {         let projectList = [];         return {             projectList: projectList         };     }()); };  export default establishArrays;  If I put console.log(globalVar.projectList) in the function, it works when run, showing [] Now establishArrays is part of a file index.js into which is imported renderProject as well. However, when I do this, function renderProject() {   console.log(globalVar.projectList) }  I get this error, Uncaught ReferenceError: globalVar is not defined at main.js:2 What could be causing this? In index.js I have imported and run them: import createUUID from './UUID'; import establishArrays from './establishArrays'; import createProjectListeners from './createProjectListeners'; import renderProject from './renderProject';  createUUID(); establishArrays(); createProjectListeners(); renderProject();  Thanks!

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


I'm currently playing with Java 8 lambda's and having a small issue.  What I want to do  I have a built a prototype website using spring, it takes in a transaction object and stores it in a map. The transaction class has a long value and String type (e.g. hotel). What I'm trying to do is, run a lambda expression that filters out all of the transaction objects which have a certain type and return a List which is the list of their keys.  Basically I just want to see a list of the keys to objects in the map which have a specific type.  Simple test I have tested it by filling in an object which has a type of car and a value of 3000. I then passed in car on the web form to filter the map based on this. I outputted what the input type is (to check the webform received it correctly), the type stored in Map object and if they're equal which is all correct, however the lambda is still returning an empty list.  I have the code written as below:  Offending Method:      HashMap<Long, Transaction> transactionMap = new HashMap<>();  @RequestMapping(value = "transactionservice/types/{type}", method=RequestMethod.GET) public ResponseEntity<List<Long>> getSameType(@PathVariable String type) {      System.out.println("Input type is: " + type);     System.out.println("What is stored at 1: " + transactionMap.get(Integer.toUnsignedLong(1)).getType());     System.out.println("Values are equal: " + type.equals(transactionMap.get(Integer.toUnsignedLong(1)).getType()));      List<Long> listSameType = transactionMap.entrySet()             .stream()             .filter(s -> s.getValue().getType() == type)             .map(Map.Entry::getKey)             .collect(Collectors.toList());     System.out.println("List size of keys: " + listSameType.size());      return new ResponseEntity<List<Long>>(listSameType, HttpStatus.OK); }   Output:  Input type is: car What is stored at 1: car Values are equal: true List size of keys: 0

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I'm transferring data from an older phone (LG G5 running Android 7) to a newer phone (Nokia 8.3 running Android 11).  I've transferred most of it using backup + restore, or manually using syncthing.  But I have one app where I can't find the data.  The app is called . guidebook has a dir /Android/data/com.guidebook.android . But I don't see any actual files there, either under internal storage or on the external SD card. I tried to download the guidebooks again on the new phone.  But my old guidebooks are no longer available to download.  Probably because guidebook is now charging the orgs per download.  They don't even give me an option to buy them. I know that the guidebooks are being stored locally because I can access them offline, with wifi and mobile data disabled. I contacted guidebook support.  They say they don't support transferring the guidebooks between devices. Anyone know how to transfer them?  Or how I can even go about finding where they are hiding the files? I tried the Android debugger, but that won't run because I don't have symbols for libraries. NB: if others want to play with this, the app is free, and it's possible to download current guidebooks for free.

Could you list all possible directories where Android apps may store data, providing description what kind of data are stored in each directory?


I'm a level 36, and I often farm for legendary weapons. The problem is, for example, when I did the clan wars mission (killing hodunks or zafords) the final battle I killed the hodunks. I was around level 20 then. Now when I farm for the legendary weapon he drops, he still is level 20 and drops the level 20 legendary weapon. My question is; how do I get the some of the bosses (tector, hunter hellquist, scorch, ect.) to scale to my level so I can get my level legendaries?  (don't know if this matters but I have beat the game and killed the warrior many times).

When I finished Normal Mode at around Level 30 and went back to the  (still at Normal mode), I found that all enemies there are now very easy to kill, meaning they didn't level up (or hit a level cap).  When I went to  as a Level 36 character in True Vault Hunter Mode, I noticed that the enemies are the same level as me.  What factors determine enemy levels?   Specifically, I would like to know:       Are enemies affected by what level a character accepted a mission?      Or is it what level a character is when they first entered an area?      How does Normal Mode, True Vault Hunter mode, and the Ultimate True Vault Hunter Mode affect enemy levels?     Are there enemies that will scale to the player level, as the player levels up? Any enemy leveling differences specific to the DLC areas?         EDIT:   There is now  that explains how this works generally: "In playthrough 1, outside of the DLC, there's no such thing as scaling. Enemy levels are determined solely by the area they're in and your mission." Can anyone expound on that, and comment or provide an answer on what are the specific enemy levels on specific areas and/or missions?    states that "enemies do not actually "scale", or at least from what we know of..." and lists specifics for enemy levels on certain areas in the game (sans DLC areas). Can anyone expound on that and/or add specifics for enemy levels in the DLC missions or areas in TVHM (PT 2.0) and/or UTVHM? The  update has just been released, can anyone provide info about enemy levels on that mode, including the DLC areas or missions?


Colombia  a population of about 100 "cocaine hippos" founded from a group of one male and three females, which escaped from a drug kingpin's private zoo; it's even estimated that this population could grow to over 1,000 in the next two decades or so:  The rise of the so-called "cocaine hippos" began in 1993 after authorities killed Pablo Escobar and seized his luxury estate Hacienda Napoles, about 250km (155 miles) north-west of the capital Bogotá. Animals found there were distributed to zoos across the country, but not the hippos. "It was logistically difficult to move them around, so the authorities just left them there, probably thinking the animals would die," Ms Castelblanco said. Instead, they thrived. Over the years, scientists have tried to calculate how many hippos are living in Colombia's waterways, with estimates ranging from 80 to 120 animals. "It is the biggest hippo herd outside Africa, which is their native region," veterinarian and conservationist Carlos Valderrama told the BBC. [...] Ms Castelblanco and her peers say the population will reach over 1,400 specimens as early as 2034 without a cull - all of them descended from the original group of a male and three females.  I'm curious however if these "cocaine hippos" don't show any signs of  given how small the founding group was. Are there any studies/articles on this aspect in that Colombian hippo population?

Today I read a  about how Pablo Escobar had once imported 4 hippos (1 male, 3 female) into his estate in Colombia for his private zoo. After his downfall, while other species were shipped out, hippos were considered too big to move and expected to not survive. However, to the surprise of all the hippos are thriving and are so numerous that there have been calls to cull them. From the report:  Numbers are projected to only get bigger. [Colombian biologist Nataly] Castelblanco and her peers say the population will reach over 1,400 specimens as early as 2034 without a cull - all of them descended from the original group of a male and three females. In the study, they envisaged an ideal scenario in which 30 animals need to be culled or castrated every year to stop that happening.  My understanding is that since there was only 1 male, the gene pool would be limited and lead to lot of inbreeding in the descendants. This would cause population to not explode because some individuals would be unfit to survive. Why has this not happened in case of hippos? Is it because there are 3 females (probably unrelated to each other) which keeps gene pool large enough? Or can mutations explain this phenomenon? Would results have been different if originally 2 females had been moved and only 1 retained? EDIT - I have just found that  is maybe less than 100 individuals which though big is not massive. EDIT2 - I have edited the question title to keep focus on the hippos although a general answer would be welcome.


Deciding whether this is true or not. I believe the statement is true just based of the definitions of what $A \cup B$ and $A \cap B$ mean. But I'm not sure how to prove this.      For any sets A and B, if $(A \cup B)$ \ $(A \cap B ) = ∅$ , then $A = B$

This is my first post on this forum :)  I've been trying for a while to solve this problem about symmetric difference of two sets:     Given two sets $A$ and $B$, we call symmetric difference of $A$ and $B$ the following:      $$A\mathrel{\triangle}B = (A\cup B)-(A\cap B)$$      Show that if $A\mathrel{\triangle} B = \emptyset$, then $(A\subset B) \vee (B\subset A)$.   I don’t know where to start; thank you very much for the help :)


I'm writing a story in which the last two words are currently "fake smile." It would be punchier if I could condense these two words into one - is there any such word?

Is there a good idiom that implies fake happiness in the same way 'crocodile tears' imply fake sadness?


I have a long algorithm that's taking three quarter of a page and so it's taking a whole page with an empty quarter. I want it to be continued with the previous text without leaving any empty place, that means that it will be divided into two pages.   I found answers  that allow to divide the algorithm into two previously set parts, however, I want the algorithm to dynamically fit into the two pages. How I can do that?   Here is an example of the situation that I am having:  \documentclass[a4paper,12pt]{report} \usepackage{natbib} \usepackage[francais]{babel} \usepackage{url}  \usepackage{setspace} \usepackage{fancyhdr} \usepackage{amsmath} %\linespread{1.15} \onehalfspacing \usepackage{makecell} \usepackage{tabularx} \usepackage{amsmath} \usepackage{algorithm} \usepackage{algpseudocode} \usepackage{blindtext} \usepackage{enumitem}   \begin{document} \blindtext Qu’est que c’est?. C’est une phrase fran ̧cais avant le lorem ipsum. Loremipsum dolor sit amet, consectetuer adipiscing elit. Etiam lobortis facilisissem. Nullam nec mi et neque pharetra sollicitudin. Praesent imperdiet minec ante. Donec ullamcorper, felis non sodales commodo, lectus velit ultricesaugue, a dignissim nibh lectus placerat pede. Vivamus nunc nunc, molestie ut,ultricies vel, semper in, velit. \begin{algorithm}[H] \caption{XXX}\label{alg:ChainProcess} \begin{algorithmic}[1] \State \textbf{Entrées:} XXX \State \textbf{Sortie:} XXX \State XXX  \For{\texttt{(\textit{i allant de 1 à (T-1)})}}     \State  XXX      \For{\texttt{( XXX}}         \State \textit{XXX}XXX         \For{\texttt{(XXX)}}                     \If{XXX)}                  \State \textit{XXX} XXX                 \State XXX              \EndIf          \EndFor          \If{(XXX) }              \State xXX         \EndIf     \EndFor      %\State  \EndFor   \end{algorithmic} \end{algorithm}  \end{document}

I'm starting my experiment with LaTeX, i'm writing an article and all that I want is to embed an algorithm inside normal text, this is my code:  \documentclass{article} \usepackage{algorithmic} \begin{document} \section{Lettura file .gpx}  Lorem ipsum ...  \algsetup{indent=1.7em} \begin{algorithm} \caption{Alg capt} \label{alg1}  \begin{algorithmic}[1] ... algorithm here... \end{algorithmic} \end{algorithm} \end{document}   This is fully working but algorithmic uses a pagebreak automatically, how can I avoid this break and show the algorithm immediately after "lorem ipsum" part?


I am studying the phasor method for solving electrical circuits. Have tried using tables and researched a lot on the internet but have not found a simple command to represent the numbers a and b in the diagram below:    Thanks for any help.

How to make the traditional division? Like that:  a |b_ r  c


When I download a PDF and try to open it from the Downloads window, it will attempt to open it in File Roller, which will complain that about PDF not being a supported archive type; I'd like to open it in Document Viewer instead. How do I do that from Firefox, other than going through Nautilus?  When opening the PDF from Nautilus, it opens the file correctly in Document viewer. I also went in about:preferences#applications and set Use Document Viewer (default) as the action for PDFs, but it didn't work.

No matter what changes i make to file associations (actions) in the 'Applications' tab in Firefox, they're totally ignored. For example, i set .wmv and .avi files to open with 'smplayer' but when i download a file and double-click on it (through the 'Downloads' window), it keeps opening with Totem player.    The default file associations through nautilus ('open with' tab) work fine, i.e. i've set smplayer as the default player and when i double-click a video file it open correctly.  I've tried to delete and recreate mimetypes.rdf but that didn't help.  Any ideas on what else should i check?


I am learning about type erasure. I know that after type erasure the generic types become either object or upper bound. But if the generic types become object is the type safety not lost? For eg the in the below example:- List<String> a = new ArrayList<String>(); a.add(10) // I can't do this, but after type erasure the generic type becomes object so where is               the check for the type?  Any help is appreciated

I read about Java's type erasure .  When does type erasure occur? At compile time or runtime? When the class is loaded? When the class is instantiated?  A lot of sites (including the official tutorial mentioned above) say type erasure occurs at compile time. If the type information is completely removed at compile time, how does the JDK check type compatibility when a method using generics is invoked with no type information or wrong type information?  Consider the following example: Say class A has a method, empty(Box<? extends Number> b). We compile A.java and get the class file A.class.  public class A {     public static void empty(Box<? extends Number> b) {} }     public class Box<T> {}   Now we create another class B which invokes the method empty with a non-parameterized argument (raw type): empty(new Box()). If we compile B.java with A.class in the classpath, javac is smart enough to raise a warning. So A.class has some type information stored in it.  public class B {     public static void invoke() {         // java: unchecked method invocation:         //  method empty in class A is applied to given types         //  required: Box<? extends java.lang.Number>         //  found:    Box         // java: unchecked conversion         //  required: Box<? extends java.lang.Number>         //  found:    Box         A.empty(new Box());     } }   My guess would be that type erasure occurs when the class is loaded, but it is just a guess. So when does it happen?


I'm having some problem with the start system for a cart based on repeater and powered rails combo. Basically I can see that they are getting power but the cart doesn't move at all, when it's parked on this end. If I move the repeater to the side and put a stone block behind the rail, the cart is doing like 1 cm movement but still not working. Any ideas how to get this schema to work ?

If a minecart is at rest on a deactivated powered rail, simply powering the rail will not make it move.  The minecart must be kickstarted somehow, e.g. by a player pushing it in the desired direction.  I'd like to make a traditional train station, where the carts stop briefly at a platform before speeding away.  However, due to this limitation, the process can not be fully automated.  What are some techniques to start minecarts from a full stop without any direct influence by the player?  If possible, I'd like to avoid sloped rails because they look bad next to a platform.


I need to find the expected value of $\frac{\sum x_i}{n-\sum x_i},\ i=1, 2, \ldots, n$, where the $x_i$'s are negative binomial $NB(1, \theta)$.   Edit: More context about the problem:  I looked for the MLE for $\theta$ using $x_i$'s, iid negative binomial variables to estimate $\theta$ which gave me $\frac{\sum x_i}{n}$. I then needed to find the MLE for $\frac{\theta}{1-\theta}$. Using the invariance property of MLEs, I got  $\frac{\sum x_i}{n-\sum x_i}$.  Now I need to show if this estimator is unbiased for $\frac{\theta}{1-\theta}$. Is there a better way than taking the expectation?

Let $Z_1, Z_2,... Z_n \sim Ber(\theta)$  Let $X$ be the number of trials before the 1st success. So $X \sim NB(1,\theta)$  First, I was asked to find an MLE of $\theta$ based on $X$. I did this by going through the MLE procedure for a single rv $X$ which yielded my estimator $\frac{1}{x}$.  Next, I was asked to find the MLE for $f(\theta)=\frac{\theta}{1-\theta}$. For this, I used the invariance property of MLEs so since $\frac{1}{x}$ estimates $\theta$, the estimator for $f(\theta)=\frac{1}{x-1}$. My problem with this estimator is that it is undefined when $x=1$.  Where did I go wrong? Thanks.


If incoming photons increase the mass and gravity of a black hole are they then some kind of source of gravity?I can not understand why equivalence of mass and energy lead as to say mass and energy are very similar.

I know a photon has zero rest mass, but it does have plenty of energy. Since energy and mass are equivalent does this mean that a photon (or more practically, a light beam) exerts a gravitational pull on other objects? If so, does it depend on the frequency of the photon?


I'm trying to sweep a profile curve along a path curve, where the path curve (the one to which I'll apply the bevel) is a simple set of straight lines and right angles.  When I set the path curve's Bevel Object to the profile curve, I get roughly the desired result, except that the size of the profile curve gets bigger as it approaches the ends of the path. Why is that, and what do I do about it? (I tried setting a straight taper curve, but that doesn't help.)  Here's a simple blend file showing the problem:      Thanks!

I know the title is a mouthful, but this is the problem: I made a curve with 90 degree corners, like so:  I then beveled it, and this was the result:  As you can imagine, this isn't very pretty. I'm looking for something like this:  How can I achieve this look?


I know that in order to make an header, you need to add === in the following line. This is an example. However, sometimes you need to add an header under a quote, because it is part of the text you want to quote. So I thought I can do something like that:  Which seems to work great in the preview, but then when publishing, this is the result:  Should that work? Am I doing something wrong? This is the post I used as a reference(I have edited it, so the current version has an header using ):

With markdown, you can use some dashes for headings. For example, this: Hello ---- this is some other text  renders as this: Hello this is some other text This is fine and works well. When I want to quote that text is when the problem arises, since this Markdown: > Hello > ---- > this is some other text  When written down shows well in the preview but not when posted:  Hello this is some other text   As an example, see an screenshot of the preview:    and a screenshot of the posted content, where the ---- becomes a <hr>:  Note a similar bug I also reported: .


I have categorical data where values are string. Gender, City and Country are my input data. My output class is also string values. The below table explains the data:  Gender      City      Country      Output  M           XYZ       A            Converted  F           KLM       Z            Converted  M           KLM       M            Not Converted  F           ABC       M            Converted  First question, can I calculate correlation between input columns and output? If yes, how and by which method? I am using Python, any suggestion on library function would be great.

I have a dataframe with many observations and many variables. Some of them are categorical (unordered) and the others are numerical.  I'm looking for associations between these variables. I've been able to compute correlation for numerical variables (Spearman's correlation) but :   I don't know how to measure correlation between unordered categorical variables. I don't know how to measure correlation between unordered categorical variables and numerical variables.   Does anyone know how this could be done? If so, are there R functions implementing these methods?


I've read many answers on this site answering this question. I'm on 16.04, so the following should take care of old kernels:  sudo apt-get autoremove  Failing that, I can remove old ones manually (keeping recent kernels as backup):  sudo apt-get remove linux-image-3.* sudo apt-get remove linux-image-extras-3.* sudo apt-get remove linux-headers-3.* sudo apt-get remove linux-image-4.0.0-x* sudo apt-get remove linux-image-extras-4.0.0-x* sudo apt-get remove linux-headers-4.0.0-x*   where I performed the last three commands for x = 3, 4, 5, 6, 7, 8. This did result in disk space being cleared, up to ~500M in some cases. However, I still see many MB of disk space being used on these old kernels in /boot:  ls -lh /boot  ...  -rw-r--r-- 1 root root  14M Dec 17  2016 initrd.img-3.19.0-33-generic.old-dkms -rw-r--r-- 1 root root  14M Dec 17  2016 initrd.img-3.19.0-61-generic.old-dkms -rw-r--r-- 1 root root  14M Dec 17  2016 initrd.img-3.19.0-64-generic.old-dkms -rw-r--r-- 1 root root  14M Dec 17  2016 initrd.img-3.19.0-65-generic.old-dkms -rw-r--r-- 1 root root  14M Dec 17  2016 initrd.img-3.19.0-66-generic.old-dkms -rw-r--r-- 1 root root  14M Dec 17  2016 initrd.img-3.19.0-68-generic.old-dkms -rw-r--r-- 1 root root  14M Dec 17  2016 initrd.img-3.19.0-74-generic.old-dkms -rw-r--r-- 1 root root  14M Dec 17  2016 initrd.img-3.19.0-75-generic.old-dkms -rw-r--r-- 1 root root  14M Dec 17  2016 initrd.img-3.19.0-77-generic.old-dkms -rw-r--r-- 1 root root  39M Nov 28 09:41 initrd.img-4.4.0-101-generic -rw-r--r-- 1 root root  15M Dec 17  2016 initrd.img-4.4.0-31-generic.old-dkms -rw-r--r-- 1 root root  18M Aug 27 18:51 initrd.img-4.4.0-57-generic.old-dkms -rw-r--r-- 1 root root  18M Aug 27 18:51 initrd.img-4.4.0-59-generic.old-dkms -rw-r--r-- 1 root root  18M Aug 27 18:52 initrd.img-4.4.0-62-generic.old-dkms -rw-r--r-- 1 root root  18M Aug 27 18:52 initrd.img-4.4.0-64-generic.old-dkms -rw-r--r-- 1 root root  18M Aug 27 18:53 initrd.img-4.4.0-71-generic.old-dkms -rw-r--r-- 1 root root  18M Aug 27 18:53 initrd.img-4.4.0-72-generic.old-dkms -rw-r--r-- 1 root root  18M Aug 27 18:53 initrd.img-4.4.0-75-generic.old-dkms -rw-r--r-- 1 root root  18M Sep 23 11:33 initrd.img-4.4.0-78-generic.old-dkms -rw-r--r-- 1 root root  39M Nov  4 17:00 initrd.img-4.4.0-98-generic    ...   and also, the old kernels are still listed as large installed packages by dpkg:  dpkg-query -W --showformat='${Installed-Size} ${Package}\n' | sort -nr | less  ...  158659 linux-image-extra-4.4.0-47-generic 158555 linux-image-extra-4.4.0-36-generic 158443 linux-image-extra-4.4.0-34-generic 158201 linux-image-extra-4.4.0-31-generic 157559 linux-image-extra-4.4.0-53-generic 157559 linux-image-extra-4.4.0-51-generic 156386 linux-image-extra-3.19.0-77-generic 156386 linux-image-extra-3.19.0-75-generic 156385 linux-image-extra-3.19.0-74-generic 156384 linux-image-extra-3.19.0-68-generic 156384 linux-image-extra-3.19.0-66-generic 156384 linux-image-extra-3.19.0-65-generic 156383 linux-image-extra-3.19.0-64-generic 156380 linux-image-extra-3.19.0-61-generic 156178 linux-image-extra-3.19.0-33-generic 150341 linux-image-extra-4.4.0-57-generic 150205 linux-image-extra-4.4.0-62-generic 150198 linux-image-extra-4.4.0-59-generic 149214 linux-image-extra-4.4.0-101-generic 149191 linux-image-extra-4.4.0-98-generic 149156 linux-image-extra-4.4.0-96-generic 148953 linux-image-extra-4.4.0-72-generic 148953 linux-image-extra-4.4.0-71-generic 148940 linux-image-extra-4.4.0-64-generic 148663 linux-image-extra-4.4.0-87-generic 148621 linux-image-extra-4.4.0-78-generic 148598 linux-image-extra-4.4.0-75-generic  ...   How can I fully clean my system of these old kernels?

On several Ubuntu machines I am constantly facing the problem of a full boot partition although I always do remove all old kernels. The problem seems to occur, as many initrd files are on the boot partition even though the related kernels are not actually installed. To give in example:  root@Jacobi:/boot# ls -lah insgesamt 202M drwxr-xr-x  3 root root 3,0K Jan 30 10:03 . drwxr-xr-x 25 root root 4,0K Jan 30 10:03 .. -rw-r--r--  1 root root 1,2M Dez 11 15:36 abi-4.4.0-104-generic -rw-r--r--  1 root root 1,2M Jan  9 22:28 abi-4.4.0-109-generic -rw-r--r--  1 root root 1,2M Jan 19 14:06 abi-4.4.0-112-generic -rw-r--r--  1 root root 187K Dez 11 15:36 config-4.4.0-104-generic -rw-r--r--  1 root root 187K Jan  9 22:28 config-4.4.0-109-generic -rw-r--r--  1 root root 187K Jan 19 14:06 config-4.4.0-112-generic drwxr-xr-x  5 root root 1,0K Jan 30 10:03 grub -rw-r--r--  1 root root  10M Jan 30 10:03 initrd.img-3.13.0-39-generic -rw-r--r--  1 root root  10M Jan 30 10:02 initrd.img-4.4.0-101-generic -rw-r--r--  1 root root  10M Jan 30 10:02 initrd.img-4.4.0-103-generic -rw-r--r--  1 root root  38M Jan 30 10:02 initrd.img-4.4.0-104-generic -rw-r--r--  1 root root  38M Jan 30 10:02 initrd.img-4.4.0-109-generic -rw-r--r--  1 root root  10M Jan 30 10:03 initrd.img-4.4.0-38-generic -rw-r--r--  1 root root  10M Jan 30 10:03 initrd.img-4.4.0-45-generic -rw-r--r--  1 root root  10M Jan 30 10:02 initrd.img-4.4.0-59-generic -rw-r--r--  1 root root  10M Jan 30 10:02 initrd.img-4.4.0-77-generic -rw-r--r--  1 root root  10M Jan 30 10:02 initrd.img-4.4.0-78-generic -rw-r--r--  1 root root  10M Jan 30 10:02 initrd.img-4.4.0-81-generic -rw-r--r--  1 root root 179K Jan 28  2016 memtest86+.bin -rw-r--r--  1 root root 181K Jan 28  2016 memtest86+.elf -rw-r--r--  1 root root 181K Jan 28  2016 memtest86+_multiboot.bin -rw-------  1 root root 3,8M Dez 11 15:36 System.map-4.4.0-104-generic -rw-------  1 root root 3,8M Jan  9 22:28 System.map-4.4.0-109-generic -rw-------  1 root root 3,8M Jan 19 14:06 System.map-4.4.0-112-generic -rw-------  1 root root 6,8M Dez 11 15:36 vmlinuz-4.4.0-104-generic -rw-------  1 root root 6,8M Jan  9 22:28 vmlinuz-4.4.0-109-generic -rw-------  1 root root 6,8M Jan 19 14:06 vmlinuz-4.4.0-112-generic   But only linux-image-4.4.0-104-generic and linux-image-4.4.0-109-generic are installed:  root@Jacobi:/boot# dpkg -l linux-image-\* | grep ^ii ii  linux-image-4.4.0-104-generic       4.4.0-104.127 amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-4.4.0-109-generic       4.4.0-109.132 amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-extra-4.4.0-104-generic 4.4.0-104.127 amd64        Linux kernel extra modules for version 4.4.0 on 64 bit x86 SMP ii  linux-image-extra-4.4.0-109-generic 4.4.0-109.132 amd64        Linux kernel extra modules for version 4.4.0 on 64 bit x86 SMP   If I delete the unnecessary initrd files manually they will be generated again as soon as I try to do an upgrade.  What could be the cause of this issue and how can I get rid of those files permanently?


Let $R$ be a Noetherian ring, $P$ be a prime ideal, and $Q$ an ideal of $R$. How to prove that $$ \text{Ass}(R/Q)=\{P\} $$  if and only if $Q$ is $P$-primary?    Update  In fact, I have proved that if $Q$ is primary, then Ann$(R/Q)$ is primary. Let $P=\text{rad}(\text{Ann}(R/Q))$, we have $Q$ is $P$-primary and $\text{Ass}'(R/Q))=\{P\}$ (where $\text{Ass}'$ consists of all primes occur as the radical of some $\text{Ann}(x)$ )

For an $R$-module $M$ I have the following definition for a submodule $N\subset M$ to be $\mathfrak{p}$-primary: this is the case when $\text{Ass}(M/N) = \{\mathfrak{p}\}$, that is, $M/N$ is coprimary or $(0)$ is a primary submodule.  Now for an ideal $\mathfrak{q} \subset R$ this definition gives that $\mathfrak{q}$ is $\mathfrak{p}$-primary iff $\text{Ass}(R/\mathfrak{q}) = \{\mathfrak{p}\}$. It can be shown that this is equivalent with $\mathfrak{p}^n \subset \mathfrak{q}$ for some $n\in \mathbb{N}$ and the condition \begin{align*} \forall r,s \in R: rs \in \mathfrak{q}, r\not\in \mathfrak{p}\Rightarrow s \in \mathfrak{q}. \end{align*}     Now I suspect that if $R$ is Noetherian, and if $\mathfrak{q}$ is $\mathfrak{p}$-primary, then we have $\sqrt{\mathfrak{q}} = \mathfrak{p}$. I have shown this for PID's, but does this generaly hold?    And if so, is every ideal $\mathfrak{q}\subset R$ then $\sqrt{\mathfrak{q}}$-primary?   Many thanks.


I have an old Win XP Professional 32-bit machine. Intel Pentium(R) 4 CPU 2,4 GHz and 1,25GB RAM. When I try to install Ubuntu 14.04 from DVD I get this message: This kernel required an x86-64CPU, but only detected on i 686CPU unable to boot please use a kernel appropriate for your CPU. What can i do?

I'm trying to install Lubuntu on my laptop (sorta old 2005). [Laptop stats: Intel® Celeron® CPU 410 @ 1.46 GHz 1.47GHz, 448 MB of RAM]  I press Install and this message appears:   This kernel requires an x86-64 CPU, but only detected an i686 CPU.  Unable to boot - please use a kernel appropriate for your CPU.   What can I do to install Lubuntu on my computer?


Suppose $X$ and $Y$ are independent of distribution $N(0,1)$, and $Z=\min(X,Y)$. Show that $Z^2 ∼ χ^2 (1)$ (even though it doesn't mean that Z∼N(0,1)) I know that: Fz(t) = P(min(X,Y)≤t) = 1−P(X>t)P(Y>t) =1−(1−P(X≤t))(1−P(Y≤t)) = 1−(1−FX(t))(1−FY(t)) But I get confused at how to make this equation equal to $χ^2 (1)$

Let $X \sim N (0, 1)$ and $Y ∼ N (0, 1)$ be two independent random variables, and define $Z = \min(X, Y )$. Prove that $Z^2\sim\chi^2(1),$ i.e. Chi-Squared with degree of freedom $1.$  I found the density functions of $X$ and $Y,$ as they are normally distributed. How would one use the fact that $Z = \min(X,Y)$ to answer the question? Thanks!


I may be asking for the impossible here, but is it possible to use the mouse in tty? I mean not the terminal, but the GUI-less tty itself? And if so, how?

I launch some text mode program (which accepts mouse input, like MC...) in text terminal and want to be able to use my mouse.    Is there some command I should enter to enable mouse support in this text terminals?


I am using the expex package to give a word-by-word translation in English of examples from foreign languages.  Because word-by-word translations can be sometimes quite long and abstract, it is conventional in linguistics to use a set of agreed-upon abbreviations. For instance, the term ergative' is abbreviated aserg'. Furthermore, I want this abbreviation to be in small caps, so I defined a new command as below.  \newcommand{\gERG}{\textsc{erg}}   The issue is that when I use the newly defined command, the word-by-word alignment is messed up. Compare an example without the new command and one with.  \ex \begingl  \gla word word word // \glb word.\textsc{erg} word word // \glft Translation. // \endgl \xe    This gives me, as expected, an example with a line of abbreviations that are aligned as follows.      (1) word      word word         word.ERG  word word         Translation.   But if I use my newly defined abbreviation as follows,  \ex \begingl  \gla word word word // \glb word.\gERG word word // \glft Translation. // \endgl \xe    I get something messy as in (2).      (2) word         word word         word.ERGword word         Translation.   If I put {} around every word, it solves the issue but that wastes time and kind of defeats the purpose of having abbreviations in the first place.  How to make sure that the newly defined command behaves?  Thanks.

I have a definition:  \newcommand{\arnold}{Arnold Schwarzenegger}   When I refer to it by:  \arnold is a   it is rendered as:   Arnold Schwarzeneggeris a    In order to have a space in front of "is" I would need to write  \arnold\ is a   Is there some other shorter way?


I have a 5TB hard drive (4.54TB in reality). Properties tells me I've used 4.45TB. It includes one system backup of roughly 1.8TB.   I decided to move everything (except system files, recycle bin, and that backup) to a new drive. Windows 7 tells me I'm moving 587GB. I've set all hidden and system files to be visible.   How is that one backup plus the rest of the files -- which together are about 2.5TB -- somehow amount to 4.45TB? What am I missing here?

How can I visualize which folders and files are taking up all of the space on my hard drive?  I'm getting some conflicting reports on the size of hard drive contents. Namely what is and isn't there and what folders are actually using the space.   I need to know which of the files or folders the culprits behind all this hidden bloat. Also there should be a print option to get it on paper.


public class List {      public static void main(String[] args) {          //java.util.List<String> slist= new ArrayList<String>();          try {                 FileInputStream f = new FileInputStream("V:/files/student.txt");                 InputStreamReader reader = new InputStreamReader(f);                 BufferedReader br = new BufferedReader (reader);                 String line = null;                 int id;                 String sname,subname,date;                 while (((line = br.readLine().trim()) != "/0")) {                 String[] parts = line.split(",\\s*");                 id=Integer.parseInt(parts[0]);                 sname=parts[1];                 subname=parts[2];                 date=parts[3];                 System.out.print(id+" "+sname+" "+subname+" "+date);                 System.out.println();                 //slist.add(sname);                 /*System.out.print(line);                 System.out.println();                 slist.add(line);*/             }         } catch (IOException e) {             // TODO Auto-generated catch block             e.printStackTrace();         }         //System.out.println(slist);     }   }   And here is the output  101 Snehal Patil Physics 17:05:2014 106 Rahul Rautwar Maths 20:05:2014 104 Akshata Guru Chemistry 17:05:2014 109 Swapnil Patil Chemistry 22:05:2014 106 Rahul Rautwar Physics 21:05:2014 101 Snehal Patil Chemistry 27:05:2014 104 Akshata Guru Maths 08:05:2014 109 Swapnil Patil Maths 25:05:2014 109 Swapnil Patil Physics 14:05:2014 104 Akshata Guru Physics 13:05:2014 101 Snehal Patil Maths 08:05:2014 106 Rahul Rautwar Chemistry 27:05:2014 Exception in thread "main" java.lang.NumberFormatException: For input string: "/0"     at java.lang.NumberFormatException.forInputString(Unknown Source)     at java.lang.Integer.parseInt(Unknown Source)     at java.lang.Integer.parseInt(Unknown Source)     at com.hcl.fileio.List.main(List.java:25)

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I have a data set which is defined over positive integers and I have reasons to believe it follows a beta-binomial distribution.  I am aware there is the betabinomial function that fits such a theoretical distribution to numerical data under the VGAM package, but I am not sure how to use this. I have taken a look at the examples provided by THE documentation but I cannot understand how to adjust them to my case. I have the following questions:  1) Could you please provide a simple example on how to use this function, given a data set?  2) In order to justify such a parsimonious approximation for a data set, I have seen people using bootstrapping among other arguments. Could this be the case here as well? If yes, could you please provide an example on how this would look like?   P.S. My data set is just 1-column.  Thank you.

I have a dataset as follows:  ni-xi 76 48 38 19 20 14 26 29 39 45 38 36 32 34 26 21 23 12 24 18 14 61 35 21 32 20 89 30 34 35  xi    0  0 16 26  1  8 23 19 24 16 16 19  0  0  0  6  8  3  5  9  5  0 34 17 13  0  1 11 13 22   I want to model this dataset as a beta-binomial distribution: $x_i \sim \mathcal{Binomial}(p, n_i)$ where $p \sim \mathcal{Beta}(α, β)$.  I use VGAM package to do the fitting.   fit=vglm(cbind(ni-xi, xi) ~ 1, betabinomial.ab, trace = TRUE) coef(fit)  VGLM    linear loop  1 :  loglikelihood = -95.9867 VGLM    linear loop  2 :  loglikelihood = -95.6633 VGLM    linear loop  3 :  loglikelihood = -95.6483 VGLM    linear loop  4 :  loglikelihood = -95.6477 VGLM    linear loop  5 :  loglikelihood = -95.6477 VGLM    linear loop  6 :  loglikelihood = -95.6477   However, I get the results as follows:  (Intercept):1 (Intercept):2      0.9006006    -0.3794863   Can anyone tell me why I get the negative parameters? How can i solve this problem.