Let's say that I have files f1, ..., f9. I want to create a  single view -- or a soft link -- say f, that displays a concatenated view over the 9 files.   For example, if I execute wc -l f the answer should be the sum of all individual wc -l fi for i in 1 to 9. If I edit any single file fi then the view f should automatically update, such as its modification time. So basically f is a soft link that tracks a sequence of files.   Is there any filesystem that supports something like this?
Does Linux have the capability to use "junctioned" symbolic links? I'm not sure if this is an actual term or not, so let me explain the concept.  I have a git repository containing all my configuration dot files in ~/dotfiles. I use symbolic links into this directory in order to "activate" them. For example, by executing ln -s ~/dotfiles/bash/bash_profile ~/.bash_profile to produce the link:  ~/.bash_profile -&gt; ~/dotfiles/bash/bash_profile   However, I find myself in a situation where I want to combine the contents of multiple files. For example, I want the ~/.bash_profile symbolic link to point to two separate files, one for each project. E.g.:  ~/.bash_profile (1) -&gt; ~/dotfiles/bash/bash_profile (2) -&gt; ~/dotfiles/proj/bash_profile   I know I can simply concatenate the two files (e.g., cat ~/dotfiles/{bash,proj}/bash_profile &gt; ~/.bash_profile), but if I can do the same thing with symbolic links, I would prefer to.  I imagine that if such a feature exists (Nix is pretty huge), then under the hood it would have to map the two different files together, hiding all sorts of complexities under the hood (mapping file offsets of all non-first "mapped" files, locking all files when writing to the junctioned symbolic link, etc, etc).  If such a feature doesn't exist, are there are plans to implement it?
Can two different planes share the same flight number? Translating cooking terms between US / UK / AU / CA / NZ prove $\frac {ab}{a+b} \geq \sum ^n_{i=1} \frac{a_ib_i}{a_i+b_i}$ Modifying list while iterating From the  on the dual of a norm:  $X$ and $Y$ are normed spaces, and we associate with each $f\in L(X,Y)$ (the space of bounded linear operators from $X$ to $Y$) the number $$\|f\| = \sup\{|f(x)|:x\in X, \|x\| \leq 1\}.$$  At some point in the proof that $L(X,Y)$ is bounded, it seems like they use the inequality $$\|fx\| \leq \|f\|\cdot\|x\|,$$ where $\|x\|\leq 1$.  I can't see why this should holds.   $\|f|\|$ is the supremum of what $|f(x)|$ can be, given that $\|x\|\leq 1$. So, given that $\|x\| \leq 1$, $|fx|$ should be bounded by $\|f\|$. But why should it be bounded by $\|f\|\cdot\|x\|$? Lagrange Multipler KKT condition I am looking at SVM, and reviewing Lagrange multiplier. Let's say with the constraint function $$g(x,y) = x^2 + y^2 -1 &gt; 0, $$ I am maximizing $$f(x,y) = x + y -1 .$$ Intuitively, since the constraint function does not provide a finite constrained region, there is no solution, and $f(x,y)$ can infinitely increase.  However, if I just plainly proceed with Lagrange multiplier calculation,  $$L(x,\lambda) = (x + y -1) +\lambda(x^2 + y^2 -1)$$ I get the solution: $$y,x = -\sqrt{2}/2, \lambda = 1/\sqrt{2}$$ And this still satisfies KKT conditions although the solution is wrong.  $$g(x) =&gt; 0 , \lambda =&gt;      0, \lambda g(x) = 0.$$  I expected that I would have some result that conflicted KKT conditions, but nothing was violated.   Does this mean that Lagrange multiplier under KKT conditions can produce a solution that cannot be solved, without giving any indication of intractability?  If functions are complicated, what's the systematic way to confirm that the optimization with inequality constraint functions is solvable using Lagrange multiplier? I'm a web designer and I'd like to make a custom wordpress theme for my upcoming blog. The template is already made in photoshop but I need a good starting point. I don't have too much experience with Wordpress but I want something that is SEO friendly which I can edit without risking getting poor search results.  I Know about Starkers and that there are other blank themes out there, but are they good for SEO? $f:\mathbb{R}^3\to\mathbb{R}, f(rx)=r^{\alpha}f(x)$ for some $\alpha&gt;0$, $\forall x\in\mathbb{R}$, for any $r\in\mathbb{R}$, could any one tell me which of the following is true?  $1.$ If $f(x)=f(y)$ whenever $||x||=||y||=\beta&gt;0$, then $f(x)=\beta ||x||^{\alpha}$  $2.$ If $f(x)=f(y)$ whenever $||x||=||y||=1$, then $f(x)= ||x||^{\alpha}$  $3.$ If $f(x)=f(y)$ whenever $||x||=||y||=1$, then $f(x)=c||x||^{\alpha}$ for some constant $c$  $4.$ If $f(x)=f(y)$ whenever $||x||=||y||$, then $f(x)$ must be a constant function. Thank you. 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 $F_\sigma$-subsets in a normal space can be separated Let $X$ be a normal Hausdorff space and let $C,D$ be two $F_{\sigma}$ subsets of $X$ such that $\overline{C} \cap D = \emptyset$ and $C \cap \overline{D} = \emptyset$.  Prove there exists disjoint open subsets $U,V$ such that $C \subset U$ and $D \subset V$.  No idea how to show this. Can you please help? I was given a laptop with a totally dead display. I do not want to pay to replace the broken display, but I would like to use the laptop as a server and connect to it via SSH to control it.  I have pulled out the internal hard drive from the broken laptop, and I want to install Debian GNU/Linux and the SSH server onto this HDD using a working Debian laptop.  However, the hardware in the two laptops is very different, and I am wondering what kind of problems I would run into when I plugged the drive back in to the laptop with the broken display because of this?  How would I make this work? What is the proper way for me to install a bootable copy of Linux onto a HDD that will be used by a computer with different hardware? !! Do not use the future tense after unless   [✓]  I won't go unless you go   [✘] [I won't go] unless you will go. [✘]   Why not? Even if the above is prescriptive, what may be some reasons? In my separate question , I quote: unless = if not. If not can precede future tense; so why can't unless?  Footnote:  motivated this. Why is OpenJDK 10 packaged as openjdk-11-*? UK Train - Can I board at a different station Do you use "a" or "an" before acronyms / initialisms? How do I create an empty array/matrix in NumPy? I can't figure out how to use an array or matrix in the way that I would normally use a list. I want to create an empty array (or matrix) and then add one column (or row) to it at a time.  At the moment the only way I can find to do this is like:  mat = None for col in columns:     if mat is None:         mat = col     else:         mat = hstack((mat, col))   Whereas if it were a list, I'd do something like this:  list = [] for item in data:     list.append(item)   Is there a way to use that kind of notation for  arrays or matrices? UK visit visa: What documents prove genuine relationship with the visitor? In the UK immigration rules for visitor visa  it states if;      Funds, maintenance and accommodation provided by a third party      V 4.3 A visitor’s travel, maintenance and accommodation may be   provided by a third party where the decision maker is satisfied that   they:      (a) have a genuine professional or personal relationship with the   visitor;and      (b) are not, or will not be, in breach of UK immigration laws at the   time of decision or the visitor’s entry to the UK; and      (c) can and will provide support to the visitor for the intended   duration of their stay.   I'm a UK  citizen. I'm planning to invite my brother-in-law and another close friend to the UK. In my invitation letter, I have clearly mentioned that I'm going to provide them accommodation only. They have prove sufficient funds to support themselves. I have sent them an invitation letter along with a copy of my passport and tenant agreement.   What other documents do I need to provide to indicate that it is a genuine professional or personal relationship with the visitor? Interactive / Real time code compilation for stackoverflow.com. That will improve the answer correctness of the stackoverflow.com.  When adding a new code block, let the user try to compile the code and see the result. It will be useful to demonstrate class designs, algorithms, and logics. What formula should be used to determine "hot" questions? Right now  is fairly broken -- it's a simple descending sort by views. As Joel said , it is &quot;a self-fulfilling prophecy.&quot; But this is not intentional, it's only because we haven't had time to improve it yet! As I sit down to write a better algorithm, I thought you guys might have some insight into what would make a good formula to determine the &quot;hot&quot; questions -- over the last 24 hours, the last week, the last month, and all time. Here are the variables we have to work with:  Votes [aka Score] Views Answers Answer Votes [aka Score] Whether the question has an accepted answer or not Time question was originally asked Time of last activity on question Reputation of asker Reputation(s) of answerers  Joel cited the reddit formula as an example, but I think our site is a little different than just a basic link submission site. Plus, we have more variables and data to work with. I found a  describing a few formulas: Y Combinator Hacker News  (p - 1) / (t + 2)^1.5 p = votes (points) from users t = time since submission in hours  Reddit  t = (time of entry post) - (Dec 8, 2005) x = upvotes - downvotes y = {1 if x &gt; 0, 0 if x = 0, -1 if x &lt; 0) z = {1 if x &lt; 0, otherwise x} log(z) + (y * t)/45000  Thoughts? Ideas? I don't want to overthink this; I just want the &quot;hot&quot; questions to be relevant and useful to us. So the simpler the algorithm the better! Based on my analysis of the above and the comments so far, here's the second version of what I have implemented so far. This might suck. I don't know:  (log(Qviews)*4) + ((Qanswers * Qscore)/5) + sum(Ascores) -------------------------------------------------------- ((QageInHours+1) - ((QageInHours - Qupdated)/2)) ^ 1.5  Note that accepted answers weight not at all in hotness. This is intentional, as I feel accepted answers are a fine social contract, but not a good data point for question or answer quality. This algorithm will heavily favor questions with LOTS of answers, as the sum(Ascores) are now included -- one assumes if there are lots of answers, there will be a lot more voting on the answers, too. Update: Note that this formula is what is used on the  linked from the homepage of each site. It is not the formula used to determine the  list. See . Clarify an idiom in a political text Please carefully read the text below:     On 24 November, 1993, a meeting of Leftist intellectuals occurred in   London under the auspices of the Institute for Public Policy   Research (IPPR), which is a Labour-leaning think-tank.  A short document   was circulated in advance of the said meeting to clarify its   purpose.        Among other things, the document declared that the task of the   IPPR was: "To do what the Right did in the seventies, namely to break   through the prevailing parameters of debate and offer a new   perspective on contemporary British politics."    The explanatory document also said, "Our concern is not to engage in a   philosophical debate about foundations of socialism."      If this meant that those foundations were not the appropriate thing to   talk about at the 24 November meeting, then that might have been   right; not every thing has to be discussed at every meeting.  But if   what was meant was that discussion of philosophical foundations is not   what the Left now needs, then I disagree, and if that indeed is what   was meant, then it is curious that the breakthrough by the Right should   have been invoked as an achievement for the left to emulate, for if   there is a lesson for the Left in the Right's breakthrough, it is that   the Left must repossess itself of its traditional foundations on   pain of continuing along its present, politically feeble, reactive   course.  If the Left turns its back on its foundations, it will be   unable to make statements that are truly its own.   Since I've heard only one definition of the part identified in bold, I am at a dead end.  As you know, and according to Oxford's dictionary, the verb "repossess" means: To take back property or goods from SB who has arranged to buy them and can not pay.  Here, the object of verb is a thing not a person, but in the text, first,itself comes before of and its traditional foundations. As a result, I thought that this phrase might be an idiom and so has a different meaning with the original verb.  Please explain the meaning of this phrase.