I know that \tilde{x} will produce  but how do I make it that \tilde will be below  ?
It is very easy to put a tilde over the symbol in math mode. Simply type $\tilde{a}$. But how to put a tilde under the symbol in math mode?
Is one preposition enough for multiple months? A colleague of mine has written her thesis and requested me to read and correct its grammar. I have seen some sentences like     The maximum deviation of the concentration values were obtained in the growing season, especially in May, in July, in August and in September.   As you see there is one 'in' for each month. I think that one preposition would be enough for all:     The maximum deviation of the concentration values were obtained in the growing season, especially in May, July, August and September.   Which one is more suitable? Show Google results along with related questions A significant number of downvotes are given to questions whose askers didn't first check Google. This seems to be closely related to downvotes from asking a question with duplicates in the "Related Questions" field. How about also showing Google's "I'm feeling lucky," or some other results, in the Related Questions to help out with that?   EDIT: to clarify, I'm not talking about questions with answers on Stack Overflow, but rather questions with easy solutions available via Google. Here's a question just like that: Using SQL Server, how do I split a string so I can access item x?  Take a string "Hello John Smith". How can I split the string by space and access the item at index 1 which should return "John"? Distribution of the digits of Pi regexp in ksh for extensions tgz, tar.tgz I'm trying to get a regexp (in ksh) to identify files with only the following extensions: tgz, tar.gz, TGZ and TAR.GZ. I tried several but can't get them to work. I'm using this regexp to select only files files with those extensions to do some work with them:  if [ -f $myregexp ]; then    .....  fi While looking at online code samples, I have sometimes come across an assignment of a String constant to a String object via the use of the new operator.  For example:  String s; ... s = new String("Hello World");   This, of course, compared to  s = "Hello World";   I'm not familiar with this syntax and have no idea what the purpose or effect would be.  Since String constants typically get stored in the constant pool and then in whatever representation the JVM has for dealing with String constants, would anything even be allocated on the heap? Number of connected components of the complement of a compact Let $X$ be a connected, locally compact space and let $K$ be a compact subset of $X$. Is the number of connected components of the complement $X\setminus K$ finite? If it is not, are there some hypotheses over $X$ for finiteness of connected components? How can I remap a keyboard key? One of my laptop's keys has fallen off. Is there any way I can remap another key to serve as that key?  I'll 'sacrifice' the other key because I never use it. What does accepting an answer actually convey (2015 edition)? Does the series $\sum\limits_{n=1}^\infty \frac{1}{n\sqrt[n]{n}}$ converge? Does the following series converge? $$\sum_{n=1}^\infty \frac{1}{n\sqrt[n]{n}}$$   As $$\frac{1}{n\sqrt[n]{n}}=\frac{1}{n^{1+\frac{1}{n}}},$$ I was thinking that you may consider this as a p-series with $p&gt;1$. But I'm not sure if this is correct, as with p-series, p is a fixed number, right ? On the other hand, $1+\frac{1}{n}&gt;1$ for all $n$. Any hints ? What is the difference between \em and \emph? What is the difference between \emph{...} and {\em ...}?  When to use each of them? Gradient of $a^T X b$ with respect to $X$ How can I find the gradient of the term $a^TXb$ where $X$ is a $n \times m$ matrix, and $a$ and $b$ are column vectors.  Since the gradient is with respect to a matrix, it should be a matrix.  But I do not have a clue on how to derive this gradient.   Any help ? Why didn't Harry himself drink Polyjuice Potion instead of all others in Deathly Hallows Part 1? In Harry Potter and the Deathly Hallows Part 1, it is shown that members of the Order of Phoenix come to rescue Harry from his house at Privet Drive. There, they all drink Polyjuice Potion and assume the form of Harry to confuse death eaters in identifying who is the real Harry.  An obvious, more safe, better choice would be to change Harry into someone else. Maybe a muggle, like his cousin Dudley. And then, safely take him to the Weasleys, maybe apparating. That way, death eaters won't ever find out. Isn't that correct?  Why didn't they take this path, and follow a rather complicated and risky one? What's a better way to define individual link colours for a url in a macro? I've got a document where I'd like two colours of links - cyan for links in headers that since it's brighter, and navy blue for links in the main body which is more subtle/less distracting. I already tried using the xcolor package and changing the text colour with textcolor, like \textcolor{cyan}{\href{url.com}{link name}}, but it doesn't override whatever link or url colour I have defined in hypersetup.   So this is what I've done:   I've defined the colour navy:   \definecolor{navy}{HTML}{2F729C}    And also imported the hyperref package and defined commands to set the global link/url colours to cyan / navy.   \usepackage{hyperref}                         \hypersetup{colorlinks=true,linkcolor=navy,urlcolor=navy}                        \newcommand{\navylinks}{\hypersetup{linkcolor=navy,urlcolor=navy}}               \newcommand{\bluelinks}{\hypersetup{linkcolor=cyan,urlcolor=cyan}}     Then I've defined another command specifically for the header links, where I turn on cyan links globally, include the header text and link, and then turn on navy links again:   \newcommand{\headerlink}[1]{\bluelinks\href{#2}{#1}\navylinks}   My issue with this is that I feel like there could be a better way to do it than to set the global link colour every time I use a link macro; is there a way to define the link colour just for one link, like one would do with \textcolor{...}, that would be able to override hypersetup? Legend inconsistent in QGIS map print layout After I did styling my vector data set to be classified by graduated circle and categorized by type, it appears beautifully consistent in the map canvas as shown below:   But when I create a print map layout and after adding the map, I add the legend and it come out ugly inconsistent like this:    So, I would like to ask for help to make the legend in the map print layout consistent as the legend shown in layer panel. I use the latest version QGIS 3.10.2 64bit. Is the function $\mbox{tr}(XAX')$ convex? Is the function $\mbox{tr}(XAX')$ convex, where $A$ is a positive semidefinite (PSD) matrix? I know that for a general $A$, the above trace function is not convex. But for a PSD $A$, is the function convex? How can I get a complete list of fields for a standard object? I am new to Apex, but it is apparent to me that most (if not all) standard objects probably have an ID field. However, this field does not appear in the reference for the standard objects in the Soap API Developer's Guide. Instead, it reads:     To verify the complete list of fields for an object, you can use a   describe call from the API, or inspect with an appropriate tool, for   example, inspecting the WSDL or using a schema viewer.   If I want to find out for sure whether an object has an ID field, or what the field is named (is it ID, Identifier, id, etc), it sounds like I need to use a "describe call" or "an appropriate tool" or inspect the "WSDL" using a "schema viewer".  Now, I am an experienced software developer, but those solutions are so ambiguous I have no idea where to look next to figure out how to get an object's ID. Can anybody either refer me to more specific documentation, or explain how to find the complete field documentation via a "describe call", "appropriate tool", or "schema viewer"? Django: AppRegistryNotReady() Package denyhosts in Ubuntu Trusty Tahr is deleted: temporary or forever? While doing a test-upgrade of our Ubuntu server to 14.04, I found that the package DenyHosts is no longer available. Installing it gives following error:  apt-get install denyhosts Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package denyhosts   Apparently it has been deleted, according to .  Will Denyhosts be available in the final release of Ubuntu 14.04? The  mention that it is possible to add pie menus. But I'm not sure how to do it.  How could I convert the mesh select mode menu's appearance:    to this?