Sometime ago, somebody asked a question concerning the simulation of a blackboard presentation written with Beamer. The question had several parts, and I am also interested in one of them, the most difficult one: how to provide the content as if someone was writing on the blackboard, that is, "character by character" (with obviously some control on the speed of the display). That is, imagine a student following a course by looking at home at some slides. I would like that as it clicks on a sort of "play" button, the "virtual piece of chalk writes" a new sentence in the slide, or some block of text. Ideally, this should also happen with the math formulas. At the end, a sound track can be added to complete the simulated teacher. It's important that the material is presented slowly, as in a real blackboard-based lesson, since this gives more time to the student to understand, even if she reads at home.  I think that if there is an easy solution, it concerns the capabilities of some pdf reader, plus a package allowing the author to control this displaying style.
I need an appearing effect for text like the one (in javascript) here .  However I don't know how to insert js code into LaTeX (apart from using the AcroTeX Bundle) and that would also force me to use Acrobat Reader, so I'd like to implement a similar effect in Beamer. Is it possible?  (of course I would love to see alternative approaches to this)
Create bash file to open minecraft launcher I use this command in the terminal to run the minecraft launcher with java 8:  /home/max/Java/jre1.8.0_25/bin/java -jar Minecraft.jar   I included the full java path because I installed it on /home as a normal user and i want to include it.   That command works, it opens the launcher with Java 8 but I want to make a bash file so I don't have to open the terminal. And, most important, I don't want the terminal to remain open when I click play in the Minecraft launcher and the game starts.  Now if i close manually the terminal when the game have started, the game is closed too. How to format hard disk in Ubuntu 14.04? Reputation has been changed but not reflected on tooltip. There has got to be the establishment of a universal auxiliary language.   Does the verb got add more to the context or is it there just for emphasis? Is it even grammatical?  Using Google-Ngrams I found a few similar versions as follow: . For example;   For many from the North, however, it has seemed difficult and there has seemed to be a problem. There has come to be a convolution between this become enmeshed concept of marriage as it exists in the sacred and how it exists in the secular. Most of the time since I have been here, there has appeared to be considerable feeling in the minds of a few. There has had to be some negotiation, obviously, but I think we provided what our soldiers need and what our country needs.   In general, I wanna know if 'have/has'+past-participle+'to be' is grammatical. Conventional parenting wisdom tells us to drive the fear of talking to strangers into our kids. Is this at all harmful though? Is there any adverse impact to a child's social development by doing this? How can you balance safety against fear? What does a "real" quantum computer need for cryptanalysis and/or cryptographic attack purposes? The cryptographic world has been buzzing the word "quantum" for a while now (even the NSA is currently preparing itself for a post-quantum crypto world) and quantum-related hardware engineering is evolving constantly. For example: the 5-qubit quantum computer created at MIT by using the technique of ion traps succeeded in prime-factorizing 15. Does that mean that since it succesfully managed that, that it is a all-purpose quantum computer which could be used for cryptanalysis and/or cryptographic attacks?   If that's not the case, what exactly would a "real" quantum computer need (think: rough description of expected technical abilities, aka specs) to enable its users to use it for cryptanalysis and/or cryptographic attack purposes? And - ignoring rumours about potentially existing but confidential governmental projects - does any such system already exist today? I'm playing around with fdisk and I tried to create a partition on an empty USB drive. Here's how that went: Command (m for help): n Partition number (1-128, default 1): 1 First sector (34-61187102, default 2048): 2048 Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-61187102, default 61187102): +30000000           Created a new partition 1 of type 'Linux filesystem' and of size 14,3 GiB.  so just one partition with 30 million sectors. However, when I check how many sectors it contains I get:  I'm checking with a different program and I see again that additional sector:  Sorry for the pettiness :) I'm learning. Adding Vertical Reference in Python to ArcGIS feature dataset Why don't wizards always use multiple wands? Using RegEX To Prefix And Append In Notepad++ I have quite a large list of words in a txt file and I'm trying to do a regex find and replace in Notepad++. I need to add a string before each line and after each line.. So that:   wordone wordtwo wordthree   become   able:"wordone" able:"wordtwo" able:"wordthree"   How can I do this? Domain of ProbabilityDistributions I'm learning about private/public IPs, port forwarding and NAT, and still fail to see the answer to a simple question:  Suppose two users on the same network are communicating with a single server outside their network (say, me &amp; my wife send http requests to yahoo.com).  The server sees both users as a single public ip, and often - as in this case - communicating on the same port.  How does the router route the packets according to the two different connections? Is there any routing info inside the packet beyond ip/port?  Is there some 'session table' maintained somewhere? By whom and what exactly does it include? How do I know if I have a selected keyframe using python? I realize that I lack any numerical intuition for logarithms. For example, when comparing two logarithms like $\log_78$ and $\log_89$, I have to use the change-of-base formula and calculate the values with a calculator in order to determine which of the two is larger.  Can anyone demonstrate an algebraic/analytic method to find out which of the two is larger without using a calculator? Two trains travel on the same track towards each other, each going at a speed of 50 kph. They start out 100km apart. A fly starts at the front of one train and flies at 75 kph to the front of the other; when it gets there, it turns around and flies back towards the first. It continues flying back and forth till the two trains meet and it gets squashed. How far did the fly travel before it got squashed?  The question is relatively simple - the trains take an hour to collide, and in an hour the fly would travel 75 km. However, the question got me wondering: Lets say you are given a time $t$ in hours(where $t&lt; 1$) How many &quot;rounds&quot; would the fly make in $t$ time? A round  is defined as moving from one train to another and back. How would I model the equation? ref to subsection number only is there a way to reference the subsection part only? Example:  \documentclass{article} \begin{document}  \section{This is my section} For further information see subsection \ref{subsecthree} within this section. \subsection{One} \subsection{Two} \subsection{Three}\label{subsecthree}  \end{document}   Usually gives (without the stars):  1 This is my section For further information see subsection **1.3** within this section.   But I want:  1 This is my section For further information see subsection **3** within this section.   Is that possible?  [Edit] To make it more clear: I am looking for a command that works like \ref, but prints (the arabic number of) the value of the subsection counter at the position of the \label.  ======================= == Solution in LaTeX ==  There is another solution below. This is a different solution I came up with  (I cannot post an answer to my own question, so I put it here):  \documentclass{article}  \newcommand{\labelsubseccounter}[1]{     \renewcommand\thesubsection{\arabic{subsection}}     \addtocounter{subsection}{-1}     \refstepcounter{subsection}     \label{#1}     \renewcommand\thesubsection{\thesection.\arabic{subsection}} }  \begin{document}  \section{This is my section} For further information see subsection \ref{subsecthree} within this section,  which is called \ref{onepointthree}, not \ref{onepointfour}. \subsection{One} \subsection{Two} \subsection{Three}\label{onepointthree}\labelsubseccounter{subsecthree} \subsection{Four}\label{onepointfour}  \end{document}   (I would like to insert the compiled code, but don't know how, sorry) There's a theorem of Kaplansky that states that if an element $u$ of a ring has more than one right inverse, then it in fact has infinitely many. I could prove this by assuming $v$ is a right inverse, and then showing that the elements $v+(1-vu)u^n$ are right inverses for all $n$ and distinct.  To see they're distinct, I suppose $v+(1-vu)u^n=v+(1-vu)u^m$ for distinct $n$ and $m$. I suppose $n&gt;m$. Since $u$ is cancellable on the right, this implies $(1-vu)u^{n-m}=1-vu$. Then $(1-vu)u^{n-m-1}u+vu=((1-vu)u^{n-m-1}+v)u=1$, so $u$ has a left inverse, but then $u$ would be a unit, and hence have only one right inverse.  Does the same theorem hold in monoids, or is there some counterexample? How can I draw outlines around 3D models? How can I draw outlines around 3D models? I'm referring to something like the effects in a recent Pokemon game, which appear to have a single-pixel outline around them: IBM Slack links broken Does anyone know where I can find working Slack invite links to any of IBM's Slack pages? The Slack links on  are all broken. Thank you. How could I go about setting the 'above' and 'below' vspaces around the equation environment?  If the same could be done for the subequations or gather environments, this would be a bonus.