Double sequence, two sequences converge, but to different limits?
When can you switch the order of limits?
What corrections can you make on galley proofs? When I receive galley proofs of a paper, I look at possible errors introduced by the copy-editing team. But while I proofread the article, there are sometimes small mistakes I'd like to fix, which were not introduced by them (i.e. they were already present in the accepted version of the manuscript).  Usually, the proofs are accompanied by instructions saying that extensive changes should not be introduced at that time, and any such changes would have to be approved by the editor (hence, I suppose, delaying publication). However, the limit is not very clear to me. What is considered extensive changes? In particular, what do you think of the following items (from my experience):   Slight changes in wording, to improve clarity Updating a citation, because an “in press” or “ASAP” article now has page numbers Adding an important (but not crucial) citation one had missed, in the introduction Adding a citation to a paper that has been published since the manuscript was submitted; possibly adding a short sentence to the text     What I have done so far is change everything that I think should be changed to improve the paper (including all the above items), and let the typesetter decide whether he wanted to send it back to the editor. I never received any complaint or comment on my changes, which could indicate that it was the correct course of action. How do I list all of the files in a commit? I am looking for a simple Git command that provides a nicely formatted list of all files that were part of the commit given by a hash (SHA-1), with no extraneous information. I have tried: git show a303aa90779efdd2f6b9d90693e2cbbbe4613c1d  Although it lists the files, it also includes unwanted diff information for each. Is there another git command that will provide just the list I want, so that I can avoid parsing it from the git show output? Can a US citizen leave and enter the US using a foreign passport? I am a dual citizen. I have both a US passport and a non-US passport. I live in the US. My US passport is currently being processed for renewal. I am unsure whether I will receive my passport in time for a trip that I have scheduled. Could I use my non-US passport to leave the US and return? I have never entered the US with my non-US passport. There is no immigration leaving the US but I still need to scan my passport for ticketing. Will the airline refuse me a ticket? I know that in this situation returning with a non-US passport can be problematic as well, but will I be able to leave at all? Note that I am traveling to a country which neither of my passports are from. If $m,n\in N$ Prove that there is such a positive integer k, such that $(\sqrt{m}+\sqrt{m+1})^n=\sqrt{k}+\sqrt{k+1}$ If $m,n\in N$ Prove that there is such a positive integer k, such that $(\sqrt{m}+\sqrt{m+1})^n=\sqrt{k}+\sqrt{k+1}$ I attempted to solve this question using binomial coefficients, saying: $(\sqrt{m}+\sqrt{m+1})^n=\sqrt{k}+\sqrt{k+1}=\sum\limits_{a=0}^n {n\choose a}*\sqrt{m}^{n-a}*\sqrt{m+1}^a$ and from here I was thinking that I had to do something with $\sqrt{m}^{n-a}$ with $\sqrt{k}$ and do something else with $\sqrt{k+1}$ and $\sqrt{m+1}^a$. Unfortunately I couldn't think of what to do with this circumstance. I then thought of maybe taking $(\sqrt{k}+\sqrt{k+1})^2=(\sum\limits_{a=0}^n {n\choose a}*\sqrt{m}^{n-a}*\sqrt{m+1}^a)^2$, but this immediately over-complicated the question. Could you please explain to me how to solve this question and how to solve similar questions in the future? PHP Change Array Keys Is there a way to change all the numeric keys to &quot;Name&quot; without looping through the array (so a php function)? [     0 =&gt; 'blabla',     1 =&gt; 'blabla',     2 =&gt; 'blblll',     // etc ... ] Which year does Spider-Man: Homecoming take place in? best way to pick a random subset from a collection? I have a set of objects in a Vector from which I'd like to select a random subset (e.g. 100 items coming back; pick 5 randomly). In my first (very hasty) pass I did an extremely simple and perhaps overly clever solution:  Vector itemsVector = getItems();  Collections.shuffle(itemsVector); itemsVector.setSize(5);   While this has the advantage of being nice and simple, I suspect it's not going to scale very well, i.e. Collections.shuffle() must be O(n) at least. My less clever alternative is  Vector itemsVector = getItems();  Random rand = new Random(System.currentTimeMillis()); // would make this static to the class      List subsetList = new ArrayList(5); for (int i = 0; i &lt; 5; i++) {      // be sure to use Vector.remove() or you may get the same item twice      subsetList.add(itemsVector.remove(rand.nextInt(itemsVector.size()))); }   Any suggestions on better ways to draw out a random subset from a Collection? Can we use non-gravatar avatars? Update:   Once upon a time there was a feature called . Its goal was to help our most active users find the questions they can answer. &quot;New nav&quot; never made it out of beta and that beta only ever made it to Stack Overflow users. Several months ago we gave new nav a sad, but overdue burial. As we promised, we've been working on a replacement for new nav, and now it's time for us to start rolling it out. We're calling it custom question lists and we are really excited about its potential to help all users get at the questions that are most interesting to them. While we hope what we've built hits the mark for many of you who have requested a feature like this (e.g., , , , , , ), we know how difficult it is to make something complex simple. So, we are rolling this out in beta to gather feedback from you and iterate on it. (Don't worry, we promise to actually release it this time.) When it's live later you'll be able to opt-in to the beta by turning on a new account preference. This will enable the feature for Stack Overflow, Meta Stack Overflow, and Meta Stack Exchange. It will be available for all network sites when the beta period is over. Schedule for future improvements This feature will roll out in four phases:  Phase I: Filter and sort controls to let you modify a question list view (Julyish) Phase II: Saved custom lists (In progress, ETA November 2018) Phase III: Notifications on custom lists (December 2018) Phase IV: Final fixes and official release (January 2019)  Sneak peak Phase I: Filter and sorts We'll add filter and sort controls to question lists. This does two things:  Clarifies the definition of built-in views - Naming is hard and short names can't always describe what a view is showing you. By exposing the filter and sort controls it is more obvious. Introduces the ability to create new custom views - This won't be super useful until we add the ability to save the views to the UI (phase II). Until then you can bookmark the URL and get back to your views.  Question list with new controls   Views drop down   Filter   Sort   Phase II: Saved custom question lists In this phase we will add the ability to save your custom questions lists. Create custom list In our current design, a dialog will be pre-populated based on the filters and sorts you're currently using. Give it a name, confirm your options, and click save.  Accessing your saved lists When you save your custom lists they will show up in the &quot;More&quot; drop down for question list views. Additionally, you can add them to the left navigation bar for easy access (see image below).  Phase III: Notifications For phase III we'll enable indicators for when new items are available in a custom question list. When you pin a question list to the left nav you can see a dot on any list with new items.  Feedback welcome As usual, we're interested in your constructive feedback. This is a work in progress and, as mentioned, will be rolled out in phases. You can provide feedback on the concepts now based on the information in this post and provide feedback based on the working elements as they are released. Created user can access all databases in PostgreSQL without any grants How do I change fonts and adjust their size? I've been finding fonts on the internet and  on my system.   What's the easiest way to change my fonts? I would prefer an easy to use graphical way, but answers with command line recommendations are also welcome. How to install the Pantheon desktop environment? Before 1994 the last Triwizard Tournament had been held in 1792, where the three headmaster judges were injured by a rampaging cockatrice.  The tournament is held every 5 years, which would put the next one in , the year . Did they carry on with the tradition, or was it deemed too risky again? Deputy badge after a reputation of 3000 Proper display of fractions How can I find the right lens cap for my lens? I own a Nikon D3000 Camera with the AF-S 18-55mm VR Kit Lens. Last week I lost the lens cap and now I want to buy a new one.  But when I went to , I got confused with the different ranges of lens names —  LC-62, LC-78, etc.  My concern is what if I order one lens cap and it won't fit correctly on my lens?  If you guys have an D3000, can you please let me know how to find the correct lens cap names? Fantasy Short Story that appeared in an anthology about 1968-1971 I read this short story around 1971.  The basic plot is for a steward to lead the king's son to another city state.  Along the way they have a number of interactions with people/subjects that demonstrate the immaturity of the son.  Last one involves the son beating up the suitor of a innkeeper's daughter.  When confronted by the steward, the son displays his contempt and chauvinistic regard of his future subjects and the steward kills him.  Turns out the trip was a test of his suitability to assume the crown and the steward explains to the king that he was not worthy.  Been looking in all the anthologies can seem unable to find it.  Thanks for your help Is there a git-merge --dry-run option? Using induction to prove that $\sum_{r=1}^n r\cdot r! =(n+1)! -1$ Use induction to prove that    $\displaystyle\sum_{r=1}^n r\cdot r! =(n+1)! -1$   I first showed that the formula holds true for $n=1$.  Then I put n as $k$ and got an expression for the sum in terms of $k$.  I then found the sum till the $(k+1)$th term by adding the $(k+1)$th term to both sides of the equation and compared it to the sum expression I get by plugging $k+1$ into the sum expression given in the question - they don't match. Non-ECC memory with ZFS: a stupid idea? I have a new server and am planning to upgrade the paltry 2 GB of memory to the maximum of 16 GB. (Theoretically 8 GB is the limit, but empirically 16 GB has been shown to work.)   advise that ECC memory is not that important, but I'm not so sure I believe this.     I've installed  and am planning to add ZFS volumes as soon as my new hard drives arrive.   Would it be stupid to skimp and get non-ECC memory for a ZFS-based NAS?  If it's necessary, then I'll bite the bullet, but if it's just paranoia, then I'll probably skip it.  Is there any reason ZFS or FeeeNAS specifically would require ECC memory, or suffer especially when running on a system using non-ECC memory?