Proving that the induced L1 and L-infinity matrix norms are duals of one another
Show that $(l_1)^* \cong l_{\infty}$
After purge mussels 6 time in salt water 20 mins each, why they still exude much grime? I  buy mussels at Pusateri and Whole Food Market for a year in Toronto. They sell them on ice and dry, not in running water.      , Bart teaches add salt to cold water and  soak for 20 mins. But I repeat 6 times...so 20 mins x 6 times = 120 mins of soaking!!! Mussels exudate less black grime every next time, but even after 6 times, water still has much black grime! See my pic under! Why? This happening for a year!     Part 2,  has GIF that shows you what I mean. Creating a copy of primary database and attaching the copy database in the same sql instance I just got into a project in which we have only one SQL Server 2012 copy. We have 12 databases attached to the primary instance of SQL Server 2012.  As I don't have SQL Server 2012 or supporting OS, I have to depend on the primary instance of SQL Server 2012.  I am not sure whether it is good to create copy/clone of all 12 databases and attach it to same instance and work on the copy for data manipulation and query testing purpose.  Based on Kin's query  SELECT    SERVERPROPERTY ('MachineName') AS PhysicalMachineName,    SERVERPROPERTY ('ServerName') AS SQLServerName,    SERVERPROPERTY ('Edition') AS ServerEdition,    CAST(SUBSTRING(@@Version,charindex('SQL',@@version, 1),15) AS VARCHAR(255)) +  ' + '         + CAST (SERVERPROPERTY ('productlevel')AS VARCHAR (50)) + ' + (Build'        + CAST (SERVERPROPERTY ('ProductVersion') AS VARCHAR (50)) +')' AS ProductVersion,     RIGHT(@@version, (Len(@@Version)-charindex('Windows',@@version, 1))+1) AS [O.S.],  SERVERPROPERTY ('Collation') AS Collation   Following is the output. I ignored PhysicalMachineName and SQLServerName.  ServerEdition : Business Intelligence Edition (64-bit) ProductVersion : SQL Server 2012 + RTM + (Build11.0.2100.60) O.S.           : Windows NT 6.1 &lt;X64&gt; (Build 7601: Service Pack 1)  Collation      : SQL_Latin1_General_CP1_CI_AS Console flashes on launching, then closes (ms-windows) Images as Planes in Eevee having weird transparency Environment variable substitution in sed If I run these commands from a script:  #my.sh PWD=bla sed 's/xxx/'$PWD'/' ... $ ./my.sh xxx bla   it is fine.  But, if I run:  #my.sh sed 's/xxx/'$PWD'/' ... $ ./my.sh $ sed: -e expression #1, char 8: Unknown option to `s'    I read in tutorials that to substitute environment variables from shell you need to stop, and 'out quote' the $varname part so that it is not substituted directly, which is what I did, and which works only if the variable is defined immediately before.  How can I get sed to recognize a $var as an environment variable as it is defined in the shell? Err http://archive.canonical.com natty InRelease     Err http://security.ubuntu.com oneiric-security InRelease                Err http://extras.ubuntu.com natty InRelease                             Err http://security.ubuntu.com oneiric-security Release.gpg   Temporary failure resolving ‘security.ubuntu.com’ Err http://archive.canonical.com natty Release.gpg   Temporary failure resolving ‘archive.canonical.com’ Err http://extras.ubuntu.com natty Release.gpg   Temporary failure resolving ‘extras.ubuntu.com’ Err http://gb.archive.ubuntu.com oneiric InRelease Err http://gb.archive.ubuntu.com oneiric-updates InRelease Err http://gb.archive.ubuntu.com natty-backports InRelease Err http://gb.archive.ubuntu.com oneiric Release.gpg   Temporary failure resolving ‘gb.archive.ubuntu.com’ Err http://gb.archive.ubuntu.com oneiric-updates Release.gpg   Temporary failure resolving ‘gb.archive.ubuntu.com’ Err http://gb.archive.ubuntu.com natty-backports Release.gpg   Temporary failure resolving ‘gb.archive.ubuntu.com’  Reading package lists... Done W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric/InRelease       W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric-updates/InRelease   W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/natty-backports/InRelease   W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/InRelease   W: Failed to fetch http://archive.canonical.com/ubuntu/dists/natty/InRelease   W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/natty/InRelease   W: Failed to fetch http://archive.canonical.com/ubuntu/dists/natty/Release.gpg  Temporary failure resolving ‘archive.canonical.com’ W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/Release.gpg  Temporary failure resolving ‘security.ubuntu.com’ W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/natty/Release.gpg  Temporary failure resolving ‘extras.ubuntu.com’ W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric/Release.gpg  Temporary failure resolving ‘gb.archive.ubuntu.com’ W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric-updates/Release.gpg  Temporary failure resolving ‘gb.archive.ubuntu.com’ W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/natty-backports/Release.gpg  Temporary failure resolving ‘gb.archive.ubuntu.com’ W: Some index files failed to download. They have been ignored, or old ones used instead.   This is what I'm seeing when I try to run sudo apt-get update. I did an update on my instance yesterday and am now experiencing this. All chromium extensions throw errors since update to 13.10 Displaying mysql data in html table PHP How to list all installed packages I'd like to output a list of all installed packages into a text file so that I can review it and bulk-install on another system.  How would I do this? How to recover a deleted NTFS partition with data I am on Ubuntu 12.04 64-bits  I accidentally deleted a NTFS 255 GB partition using Gparted, and yes it contains LOTS of important data.  Upon realizing the deletion I haven't yet created any file-system on it. So it still shows Unallocated.    I tried Testdisk , but it shows entire partitions created from the beginning.  This sdb is my secondary drive with Xubuntu and Kubuntu on it. And that 255 GB NTFS  partition was cross platform storage drive.  I am currently in sda with Ubuntu and Win7 in dual boot, which enables me to use it as Safe recovery option rather then Live USB drive.   First ,  should i allocate it to ? file-System for better recovery .  Second , i really need to recover data from this drive so please give me possible  suggestions and proven methods of data recovery.  Third ,does Testdisk requires deleted partition to be allocated for its recovery .  I am currently trying the answer seen here  with Testdisk scanning for partition second time, hoping to recover it.   It looks a duplicate but i can't confirm if the OP got it right. Since my first doubt is to allocate it or not.  If any clarification required please do comment ,i will add it.  Edit: TestDisk deeper search results.      The following partitions can't be recovered:          Partition               Start        End    Size in sectors     &gt;  HPFS - NTFS          22241 107 11 55592   3 27  535777280        FAT32 LBA            274460 158 19 460576 228 16 2989957948  NTFS, 274 GB / 255 GiB &amp; for FAT32 LBA 1530 GB / 1425 GiB showing that a group of order 45 is abelian Upon realizing it is a sarcophagus, he decides to sacrifice himself (I think by disconnecting his air) and exist in it for eternity along with the original creature. It may have been in an old Omni magazine, or some other periodical. I thought it may have been in the anthology "Dead Astronauts" but I did not find the story in there. Make all footnotes numbered subsequently, but one with a symbol Gamma Distribution out of sum of exponential random variables Should the first word after a colon be capitalized? Best Way To Store Multiple Flags In Database I have a web-based application that notifies users of activity on the site via email. Users can choose which kinds of notifcations they want to receive. So far there are about 10 different options (each one is a true/false).  I'm currently storing this in one varchar field as a 0 or 1 separated by commas. For example: 1,0,0,0,1,1,1,1,0,0  This works but it's difficult to add new notification flags and keep track of which flag belongs to which notification. Is there an accepted standard for doing this? I was thinking of adding another table with a column for each notification type. Then I can add new columns if I need, but I'm not sure how efficient this is.  Thanks in advance! Quotient group $G/H$ is abelian iff $[G,G] \subseteq H$ Show $\inf_f\int_0^1|f'(x)-f(x)|dx=1/e$ for continuously differentiable functions with $f(0)=0$, $f(1)=1$. Import error when opening empty notebook Do professors get paid for supervising students?