Elizabeth's necklace changes to the opposite?
Elizabeth's Brooch - follow-up question
How to fix dpkg error [2]? Every time I try to install or remove a package, I get this error. I thought maybe it was the hard disk, but a disk check gave me a clean bill of health. dpkg: unrecoverable fatal error, aborting: reading files list for package 'linux-headers-3.16.0-31': Input/output error E: Sub-process /usr/bin/dpkg returned an error code (2) A package failed to install.  Trying to recover:  I tried the solution of removing the listing for this file from the dpkg status file, but to no avail. I tried purging the package but no use. I'm stuck at this point as nothing I can find on Google helps. Update: This is now what the error says: dpkg: unrecoverable fatal error, aborting: E: Sub-process /usr/bin/dpkg returned an error code (2) A package failed to install.  Trying to recover:  After trying:  Update2: Seems the drive has bad sectors, but the reallocated sector count is 0. The drive is relatively old, however, so I expect some issues. I won't be able to replace it immediately, and until then I would still like to be able to keep the system up to date (especially for security reasons). I noted that there was an issue with coping some md5 checksums related to the package mentioned in the error, but I don't know what to do with those, such as if clearing them would allow dpkg to continue. "Ghost" UI elements Occasionally, I get part of an application lingering behind on my desktop:    This is part of a context menu for an application. It is always top-most, meaning that it is always on the screen, and I cannot click on it (it just clicks through it). It has happened before, sometimes with whole windows. It remains on screen even if the application it originated from is no longer running.  How do I get rid of it without rebooting? Continued fraction of $e^{-2\pi n}$ I found this problem on a well-known problem solving website. It is apparently from Ramanujan.     With   $$\LARGE{a = \frac{1}{1 + \frac{e^{-2\pi}}{1 + \frac{e^{-4\pi}}{1 + \ddots}}}},$$   what is $a$?   The basic methods I know for questions of this type were not helpful to me.  I do not require a full solution, but feel free to post one if you would like. Hints or lecture notes on how to solve problems of this nature would be appreciated.   Keep in mind that I am at an undergraduate level in mathematics. I'm trying to purchase a domain name that was registered and apparently already expired. This is its status:  Status: clientHold http://www.icann.org/epp#clientHold Status: clientTransferProhibited http://www.icann.org/epp#clientTransferProhibited Status: redemptionPeriod http://www.icann.org/epp#redemptionPeriod Updated Date: 14-oct-2015 Creation Date: 01-sep-2014 Expiration Date: 01-sep-2015   From what I'm seeing from ICANN policies, it should already be available to be registered by third parties, but maybe I'm missing something. When will it become available for me to register it? how to get rid of arm64 in apt W: Invalid 'Date' entry in Release file /var/lib/apt/lists/_var_cuda-repo-8-0-local_Release N: Skipping acquire of configured file 'non-free/binary-arm64/Packages' as repository 'http://repository.spotify.com stable InRelease' doesn't support architecture 'arm64' E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.161 80] E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-updates/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.161 80] E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-backports/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.161 80] E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-security/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.161 80] E: Some index files failed to download. They have been ignored, or old ones used instead.   After I installed Jetpack for Jetson tx1, my ubuntu constantly tries to fetch arm updates. Is there a way to disable this?  EDIT:   $dpkg --print-architecture amd64  $dpkg --print-foreign-architectures i386 arm64   I see that arm64 is included in foreign architectures. How do I remove it? Is Java "pass-by-reference" or "pass-by-value"? Capture console exit C# I have a console application that contains quite a lot of threads.  There are threads that monitor certain conditions and terminate the program if they are true.  This termination can happen at any time.  I need an event that can be triggered when the program is closing so that I can cleanup all of the other threads and close all file handles and connections properly.  I'm not sure if there is one already built into the .NET framework, so I'm asking before I write my own.  I was wondering if there was an event along the lines of:  MyConsoleProgram.OnExit += CleanupBeforeExit; 2D random walk within a bounded area I am new to linux/ ubuntu and just downloaded the v11 of ubuntu to learn linux. I faced this "No root file system is defined" error while trying to install it. This is how I was proceeding -    Downloaded ubuntu v11 from the ubuntu.com website, wrote the iso into a bootable cd, and then got into the linux installation process on restarting; everything fine till here. In one of the screen during installation, there are three choices - install alongside windows, something else etc.. Since I have windows 7 in the C drive, I selected the first option - "Install alongside another OS".      Let me interrupt here to give my existing system details - HardDisk   size: 640GB.  Number of existing partitions - 5 C drive - label   windows - 160GB - has windows 7 installed D drive - label linux -   160GB - does not have any data E drive - label backup - 100GB - has   some data F drive - label entertainment - 100GB  - has some data G   drive - label work - 90GB  - has some data All of the above are in   NTFS format.    In the screen that follows, an image is shown with 2 parts and each part is shown to have size equal to 80GB. There is a horizontal slider in the middle of these two images, with which I can resize the partitions. The right side partition is labeled Linux. There is also an option to do 'advanced partitions'. On clicking advanced partitions on the above screen, a new screen is shown in which the partitions existing in my computer are shown - but the labels are different. I see that there are two partitions with size = 160GB each (as expected), and so I assumed that the first 160GB would be my existing C drive and the second on would be the partition which I had labeled as linux (drive D). So I selected the linux partition and clicked on proceed/ install now, and then this error was shown - "No root file system defined".. and I cannot proceed after this.   Please let me know two things here:   During the screen in point number 3 above, the image with slider was shown. Which partition (drive c: or d: or anyother) is being referred to here? Which one am I actually resizing - is it the existing c: drive which has windows 7 installed already, that is getting shrunk and then ubuntu getting installed in the remaining space? What does ""No root file system defined" error mean? How do I select the proper partition and continue with the installation?    P.S.:  I had already partitioned my drives as mentioned above, and the D drive with 160GB was specifically left free for installing ubuntu. I would like to Select D drive during setup and install ubuntu here, while still keeping the already installed windows7 in C drive.  Thanks! Black hole "no hair" theorem The  (or conjecture), suggests that black holes can be entirely described by their mass, angular momentum and charge. All other details of the BH formation are lost.  Is there a simple way of understanding why you would be able to tell the difference between a BH made from protons and one made from electrons, but not between one made from matter rather than anti-matter?  i.e. What is special about charge, and why aren't lepton number, baryon number, strangeness etc, also black hole properties? Thus is a picture of both of my hard-drives:    My C Drive and my D drive. I want to put Ubuntu onto my D Drive. Now my question here is if i do install onto my D Drive then how should I do it in order to retain use of the drive. I intend to partition about 60 gigs from it. Now after doing that I should still have about 830 gigs left. I want to still be able to use that in Windows. So how and will I be able to retain use of the drive after Installing? I have installed once before and I believe i did it wrong because not only could Windows not recognize my D drive but I also lost all the data on it.   My computer is a Lenovo Y700 It is a UEFI (I believe i got that right). Canonical Isomorphism Between $\mathbf{V}$ and $(\mathbf{V}^*)^*$ For the finite-dimensional case, we have a canonical isomorphism between $\mathbf{V}$, a vector space with the usual addition and scalar multiplication, and $(\mathbf{V}^*)^*$, the "dual of the dual of $\mathbf{V}$." This canonical isomorphism means that the isomorphism is always the same, independent of additional choices.   We can define a map $I : \mathbf{V} \to (\mathbf{V}^*)^*$ by $$x \mapsto I(x) \in (\mathbf{V}^*)^* \ \text{ where } \ I(x)(f) = f(x) \ \text{for any } \  f \in \mathbf{V}^*$$  My Question: what can go wrong in the infinite-dimensional case? The notes I am studying remark that if $\mathbf{V}$ is finite-dimensional, then $I$ is an isomorphism, but in the infinite-dimensional case we can go wrong? How? Why many abstract nouns get an indefinite article while it's taught that abstract nouns shouldn't get it? Probability that median falls within a range? If I draw 5 samples from a distribution that is cont., what is the probability that the median of the population is between the xmin and xmax of the draw samples?  What is the formula to apply here? I am trying to filter items with a stored procedure using like. The column is a varchar(15). The items I am trying to filter have square brackets in the name.  For example:  WC[R]S123456.  If I do a LIKE 'WC[R]S123456' it will not return anything.  I found some information on using the ESCAPE keyword with LIKE but I do not understand how to use it to treat the square brackets as a regular string. Given that $f:[0,1]\to \Bbb{R}$ is a continuous function, I need to show that $$\lim_{n \to \infty}\prod_{k=1}^{n}\left(1+\frac{1}{n}f\left(\frac{k}{n}\right)\right)=e^{\int_0^1f(x)dx}$$  Writing $$y=\lim_{n \to \infty}\prod_{k=1}^{n}\left(1+\frac{1}{n}f\left(\frac{k}{n}\right)\right)$$ and taking the logarithm of both sides and interchanging limit and logarithm(since $f$ is continuous), I get $$\log y = \lim_{n\to \infty}\sum_{k=1}^{n}\log\left(1+\frac{1}{n}f\left(\frac{k}{n}\right)\right)$$ Now I know that the limit of the Riemann sum $\lim_{n\to \infty}\sum_{k=1}^{n}\frac{b-a}{n}f\left(a+\frac{(b-a)}{n}k\right)=\int_a^bf(x)dx$. However if I want it to read $\int_0^1f(x)dx$ in the given problem, I would need the term inside the summation to read $\frac{1}{n}f\left(\frac{k}{n}\right)$. The way to do this it would seem is to take the series expansion of $\log(1+x)$ and ignoring the $x^2$ and higher order terms. Is it justifiable to do so? I'm designing a small module that breaks out a DIP SPI EEPROM to a 2x5 pin header socket(more info here: ). I want to mount the socket on the end of the board, with the pins lying parallel to the board.  I think two 5x1 surface-mount header footprints, on both sides of the board right near the end would do the job. Trouble is, KiCAD doesn't come with such a footprint(if it does, I haven't found it yet). Where might I find one? If one doesn't exist, that's OK; I'll have a shot at making my own. Making a div vertically scrollable using CSS Self-deleted posts and the 3 vote / 60 day rule With regards to  post about  and the part about retaining reputation earned from deleted posts that have a score of 3 or better and were visible on the site for 60 days, does this also apply to self-deleted posts and will it continue to do so? I culled a few of my own answers over the weekend that were less than stellar, and my reputation dropped 1.8k, but the rep is back today after the changes were announced. I thought it would be useful to clarify that this also applies to self-deleted stuff. I have iterate over numbers in various order. I am able to display them in increasing order, even with steps like:  $ seq --separator="," 1 10 1,2,3,4,5,6,7,8,9,10 $ seq --separator="," 1 2 10 1,3,5,7,9   I am also able to display them in reverse order, neither continuous nor step wise.  $ seq --separator="," 10 1    $ seq --separator="," 10 2 1   No output for above commands.   My shell details:  $ bash --version GNU bash, version 3.2.25(1)-release (x86_64-redhat-linux-gnu) Copyright (C) 2005 Free Software Foundation, Inc.   Let me know how I would be able to display the numbers in descending order?