Is WGS84 a Coordinate system or projection system?
Difference between projection and datum?
Let $a$ and $b$ be natural numbers with $ab&gt;2$. Suppose that the sum of their highest common factor and least common multiple is divisible by $a+b$. Prove that the quotient is at most $\frac{a+b}4$. When is this quotient exactly equal to $\frac{a+b}4$. So, floor is a function that converts a real number to an integer. It rounds down. This makes sense; however, what about complex numbers? I know that depending on the number, it can be split linearly. However, I do not know what $\lfloor i\rfloor$ equals. Is there a clearly defined definition of $\lfloor i\rfloor$? How to add custom C++ keywords to be recognized by Minted? When should I use the "strictfp" keyword in java? I've looked up what this does, but does anyone actually have an example of when you would use the strictfp keyword in Java? Has anyone actually found a use for this?  Would there be any side-effects of just putting it on all my floating point operations? I am a third year (starting fourth year in the fall) PhD student in mathematics. I've passed all qualifying exams and am currently doing research. As far as I can tell, I am not doing poorly. I have the good fortune of having a great advisor, being in a very supportive department, and having friends and family who genuinely care about my success.   The fact is research is hard. It appears to consist primarily of staring at a problem for days and days and days without getting anywhere. Sometimes, rarely, I do figure something out and that feels wonderful, but the overwhelming majority of my time appears to be spent banging my head against a mostly figurative wall. I am not complaining about the material being hard, and I am not averse to putting in hard work, but I get frequently discouraged when I realize the vast volumes of mathematics that I yet know nothing about (and probably never will). It's very hard to quantify progress - in particular, there are too few tangible returns after too many hours worked. I find myself thinking along the lines of "Oh, if only someone actually smart were thinking about this problem they would have solved it in moments" and so on.   I've talked about this to some number of people; here is some advice I have received:   Take a day off. Putting in hours upon hours of trying things doesn't magically lead to a solution, particularly if the brain is tired and just wants to sleep. Have a hobby. Since math research doesn't exactly provide instant gratification, a hobby might provide some instead.  Talk to other graduate students. Realize that many graduate students go through this.   I'm interested to know how other folks have dealt with being discouraged as a graduate student. Does it get better with time and experience? Is this a sign that research is not for me and that I should seriously consider a life outside academia? I need to include code in the appendix of my thesis. The code contains comments and the compilation instantly breaks returning:  Unicode char �\lst@FillFixed@ (U+5A8) (inputenc)                not set up for use with LaTeX. l.160       if (lastArg &lt; 0, lastArg = 360°                                               + lastArg);   This is only one of many characters which produce problems. I cannot change my entire code just because this won't compile. Is there any way to include code with arbitrary unicode characters? Thank you.   Edit: complete sample code, as requested.  \RequirePackage[l2tabu,orthodox]{nag}   \documentclass[headsepline,footsepline,footinclude=false,oneside,fontsize=11pt,paper=a4,listof=totoc,bibliography=totoc]{scrbook} % one-sided   \usepackage[toc,page]{appendix} \usepackage{listings} \usepackage[utf8]{inputenc}  \lstset{     inputencoding=utf8,   extendedchars=true,   basicstyle=\footnotesize\ttfamily,   showstringspaces=false,   showspaces=false,   numbers=left,   numberstyle=\footnotesize,   numbersep=9pt,   tabsize=2,   breaklines=true,   showtabs=false,   captionpos=b,     literate={ö}{{\"o}}1 {ä}{{\"a}}1 {ü}{{\"u}}1  }  \begin{document}  \begin{appendices} \lstinputlisting{code/power_series.html} \end{appendices}  \end{document}   Relevant content of power_series.html:  if (lastArg &lt; 0, lastArg = 360° + lastArg);   There really is not much to say about this problem. I only want to be able to use all unicode characters inside a listing. Thank you. Compute the Riemann integral  $$\int_0^{\frac\pi2}\frac{\mathrm d \theta}{\sqrt{\sin \theta}}$$  It seems very difficult, I don't know how to go ahead.  Thank you very much for your help! Resetting Ubuntu to factory settings How are Anonymous inner classes used in Java? In shell scripts used for unit testing with dynamic libraries in a directory other than the typical @rpath, I have previously been able to set DYLD_FALLBACK_LIBRARY_PATH to set the directory containing the libraries. Under 10.11.1, bash seems to ignore attempts to set this environment variable:  $ sh -x testscript.sh + DYLD_FALLBACK_LIBRARY_PATH=/Users/something/testinglibs + export DYLD_FALLBACK_LIBRARY_PATH + exec printenv   and DYLD_FALLBACK_LIBRARY_PATH is not present in printenv's output.  Is this a security-related hack in 10.11's shell? I haven't been able to find this change documented in man pages or online. Pagination broken when merging search results with additional WP_Query On the search results page (search.php) I would like to perform an additional WP_Query to keep a specific order of search result types e.g. search results from authors should always be shown before the other results -  The first few pages should hold the author results, the other results should be shown on all the following pages only (not mixed on each page).  global $wp_query; //holds the results of the initial search query  $authorposts = $wp_query-&gt;posts;     $query = new WP_Query( 'year=2012&amp;monthnum=12&amp;day=12' ); $otherposts = $query-&gt;posts;  $wp_query-&gt;posts = array_merge( $authorposts, $otherposts  ); $wp_query-&gt;post_count = count( $wp_query-&gt;posts );  if ( have_posts() ) : while ( have_posts() ) : the_post(); ?&gt;   //show results loop...   The problems appear with the behaviour of pagination - while the $authorposts seem to paginate correctly i.e. correct page numbers for author posts and pagination works as only those where existent. But the $otherposts on the other hand are shown at the bottom of each page, right under the author posts. And they are the same on every page! Also the page count reflects the count of the first query only.  I have also tried to merge with the plus operator:  $wp_query-&gt;posts = $authorposts + $otherposts;   but in this scenario the $otherposts don't show up at all and the page count stays the same (page count for author posts).  All the examples with similar goals using two separate queries I've seen looked quite the same -  So I'm wondering if the my way of extending the original search query results with that additional WP_Query is sufficient or if I'm missing some $wp_query fields to be populated (correctly)? What's the correct way doing this?  Update: It should be noted that I'm using the WP-PageNavi plugin to paginate but this should not be relevant in the first place as the first page is already rendered wrong. And it's also initialized with the query object: wp_pagenavi( array( 'query' =&gt; $wp_query )); Catalina not allowing to change read/write permissions despite having SIP disabled Currently Running: macOS Catalina 10.15.1 Issue: Ever since I upgraded to Catalina, macOS is not allowing me to change read and write permissions on system protected files, hence, I am not able to tweak the system as per my likes and dislikes. Steps Tried To Solve The Issue: SIP, always remains . So, no question arises regarding any conflict with system integrity protection. I have also tried to force change the permissions on the system files I want to edit using certain brute force commands, which I can't recall the name of, right now. But, I have tried. As of now, I am still unable to change read and write permissions on system protected files and resources. Can I easily travel in Italy by bus/train without any prior reservation? I am planning a trip to Italy this coming January. My plan is to land by plane in Roma and then go to France by train/bus stopping in some Northern Italian cities on the way, enjoying the architecture, the atmosphere, the art and and the food.   I want to do it at my own pace, without heavy scheduling. Ideally, I would just decide which cities to visit, and take a train whenever I feel it. I often do this here in South Korea where I am living, taking advantage of the "standing seats" as it is called here, that is travelling (for a cheap price and no reservation) standing on the romm between two cars. From my experience, it is also doable in Taiwan (at least in some trains).  In France, regional trains usually does not need any reservation, so you can buy a ticket and take the train whenever you want.  Can I expect a similar system in Italy, that is a way to make short travels between close cities without reservation?   Example of "short travel": Pisa - Firenze. Function that returns the second argument of Reap Initialize class fields in constructor or at declaration? I've been programming in C# and Java recently and I am curious where the best place is to initialize my class fields.  Should I do it at declaration?:  public class Dice {     private int topFace = 1;     private Random myRand = new Random();      public void Roll()     {        // ......     } }   or in a constructor?:  public class Dice {     private int topFace;     private Random myRand;      public Dice()     {         topFace = 1;         myRand = new Random();     }      public void Roll()     {         // .....     } }   I'm really curious what some of you veterans think is the best practice. I want to be consistent and stick to one approach. I cannot find the Polygon Neighbors tool. I have searched for it as I usually do and I have also browsed the proximity toolset but it is not there. The other Tools, e.g. Buffer and Near are there and work fine. Here is a screenshot: In Bash, when to alias, when to script, and when to write a function? How exactly using VB6 can I can call any Windows shell command as you would from the command-line?  For example, something as trivial as:  echo foo how many permutations of {1,2,...,9} How many permutations of {1,2,…,9} are there such that 1 does not immediately precede 2, 2 does not immediately precede 3, and so forth up to 8 not immediately preceding 9? One obvious example of such a permutation might be 987654321, but there are many others, such as 132465879 or 351724698. Ireland Transit Visa when flying from IND - Abu Dhabi - Dublin - US