Comparing BLE device name to string
What is a NullPointerException, and how do I fix it?
The black book knowledge Javascript to check whether a checkbox is being checked or unchecked I'd like to "add to" an existing command by writing something like  \renewcommand{\somecommand}{\begin{something}\somecommand\end{something}}   but (not surprisingly) I get errors about being "too deeply nested".  Is there a way to take an existing command, add to it (by appending or prepending additional commands or text), and then have that "augmented" command replace the existing command? What would make a question popular with high views? I was wondering what might be making my questions less attractive to users?  I get very low views most of the time. What should be done to increase a question's popularity? I recently installed Ubuntu 17.10, and when I tried to set my keyboard layout to change with alt+shift, I hit a . There is  which works, but then it creates an unwanted behaviour on Firefox (perhaps other programs as well).   After setting alt+shift through gnome-tweak-tool as the combination to change language, whenever this combination is pressed within Firefox, it triggers a toggle that Firefox uses to show/hide the Menu Bar (with File/Edit/View etc.), and 'focus' is taken away from wherever the cursor was.   It's very frustrating, because one has to go and click again at the cursor.  The only solution I found was to permanently enable Menu Bar in Firefox because then alt doesn't do anything and I can use it to change languages. But I don't want to have Menu Bar on top always.  I hope you can understand what I'm trying to explain.  Any thoughts? probability of $k$ boxes contain exactly $1$ ball I went for B1 U.S. Visa at the U.S. Embassy in Delhi.   Interviewer: *Good Morning*. Me: *Good Morning* Interviewer: *What is your designation?* Me: *I am a Software Engineer.* Interviewer: *What is the name of your company?* Me: *It is XXX (I replied).* Interviewer: *What is the name of your client?* Me: *It is YYY (I replied).* Interviewer: *Have you ever been to U.S. before?* Me: *NO* Interviewer: *Have you ever been abroad before?* Me: *NO*   At this point he rejected my Visa with letter mentioning 214 (b) as the reason. I don't know why he actually rejected it.  But, I have decent 2+ years of experience with my company. And, I was going on a business meeting with the client. I would have come back after 2 weeks.  I don't know if re applying will help. How can we recover the Newtonian gravitational potential from the metric of general relativity? The Newtonian description of gravity can be formulated in terms of a potential function $\phi$ whose partial derivatives give the acceleration:  $$\frac{d^2\vec{x}}{dt^2}=\vec{g}=-\vec{\nabla}\phi(x)=\left(\frac{\partial\phi}{\partial x}\hat{x}+\frac{\partial\phi}{\partial y}\hat{y}+\frac{\partial\phi}{\partial z}\hat{z}\right)$$  However, in general relativity, we describe gravity by means of the metric. This description is radically different from the Newtonian one, and I don't see how we can recover the latter from the former. Could someone explain how we can obtain the Newtonian potential from general relativity, starting from the metric $g_{\mu\nu}$? What does the factorial of a negative number signify? I understand that the factorial gives the number of arrangements. For example: the factorial of zero i.e. an empty set ( doesn't occur) is 1.   As the empty set can be arranged only in 1 way - i.e. by filling nothing. Now, let's take an example: 5 distinct seats. How many ways 5 distinct seats can be arranged? - 5! ways i.e. 120.  So, basically, factorial gives us the arrangements. Now, the question is why do we need to know the factorial of a negative number?, let's say -5. How can we imagine that there are -5 seats, and we need to arrange it? Something, which doesn't exist shouldn't have an arrangement right? Can someone please throw some light on it?. I saw some research done on the formula - Looking for the name of a card-battle cartoon show Looking for a show about a group of three kids/teens who, using cards to change into monsters, fight and recover relics. I believe there are two or three other groups of three also trying to get the relics.  In the main group there are two boys and a girl. The boys were both white, one is from a farm and I don't know where the other is from. The girl was dark skinned and either black or blue hair. The three travelled around the world using a red plane.  I think they only use one monster primarily. The girl uses a monster created from gas and at one point is green. One of the boys uses a metal robot most of the time and at one point is given another better version of that card to use. I believe the episode for this was called something like green with envy.  All I'm getting from the internet is that it may be Chaotic, but that isn't the right show.  I also believe the girl's name was Mai and one of the boys were Ky, but I may be wrong. Calculating the area of an irregular polygon Given the length of the sides of an irregular polygon (no coordinates provided) how do you compute the area of the maximum area of the polygon?   Thanks in advance I'm trying to update an existing Subscriber in the All Subscriber Table through the API; i've set up the AppId in the App Center and have connected and created Subscribers, but i'm still having issues updating.  What call do I need to be making to do this? These are the ones i've been trying. Can a Sorcerer protect their friend from Web by using Careful Spell? With the metamagic "Careful Spell" does the caster protect his friend from a Web spell for its full duration or just for the first save? If the friend stays in the area or re-enters the area does he continue to automatically save against the restraining effect? Xerces error: org.apache.xerces.impl.dv.dtd.DTDDVFactoryImpl build argument lists containing whitespace In bash one can escape arguments that contain whitespace.  foo "a string"   This also works for arguments to a command or function:  bar() {     foo "$@" }  bar "a string"   So far so good, but what if I want to manipulate the arguments before calling foo?  This does not work:  bar() {     for arg in "$@"     do         args="$args \"prefix $arg\""     done      # Everything looks good ...     echo $args      # ... but it isn't.     foo $args      # foo "$args" would just be silly }  bar a b c   So how do you build argument lists when the arguments contain whitespace? How do I turn off the Minecraft 1.7.2 Super Secret Settings? How do I turn off the Minecraft 1.7.2 super secret settings? I tried F3 and F4, hitting Esc repeatedly, all things mentioned on blogs – nothing is working. Comma separated values in one column - SQL SERVER I see that the code in many packages and examples contains percent signs % at the end of (many) lines. What are they used for? Do they affect the parsing of those lines? TeXLive Pretest 2018: beamer and subfig collide \documentclass{beamer}  \usepackage{subfig}  \begin{document}  test  \end{document}   returns undefined control sequence \@@magyar@captionfix  (It was not so in January; I am on fully updated pretest) Converse of Schur's Lemma in finite dimensional vector spaces I am trying to prove (or disprove) the converse of Schur's Lemma in finite dimensional vector spaces. I am not sure if it holds in this case, but I have tried to apply the idea that proves it in representation theory (see for example Theorem 4.3  that uses Maschke's theorem or in questions  and ).  The converse of Schur's Lemma in finite dimensional vector spaces is:     Let $V$ be a finite dimensional vector space over the complex numbers. Let $S$ be a set of endomorphisms of $V$ and assume that every endomorphism $A$ of $V$ such that $$AB=BA\text{ for all }B\in S$$ is of the form $\lambda I, \ \lambda\in\mathbb{C}$. Then $V$ is a simple $S$-space.   (*an endomorphism of $V$ is a linear operator from $V$ to $V$  *$V$ is a simple $S$-space if the only $S$-invariant subspaces of $V$ are $V$ itself and the zero subspace)  What I've tried so far:  Assume to the contrary that $V$ is not a simple $S-$space. Then, there exists a subspace $W$ of $V$ such that $W\not =\{0\}$, $W\not= V$ and $W$ is $S$-invariant. Let $W'=V\setminus W$. Then, since $V$ is finite, we can easily prove that $V=W\oplus W'$ (this is my attempt to translate Maschke's theorem in vector spaces). Consequently, for every $v\in V$, there exists unique $w\in W$ and $w'\in W'$, such that $v=w+w'$. Define the projection $P:V\rightarrow V$ by $Pv=w$ for every $v\in V$.   What is left to prove is that $PB=BP$ for all $B\in S$. Then $P$ is clearly not a scalar and thus we have the contradiction we are looking for.  There is a difficulty in showing that $PB=BP$ for all $B\in S$, because $W'$ might be $S$-invariant or not. More precisely:   Let $v\in V=W\oplus W'$ and $v\not =0_V$.  If $v\in W$ then $Bv\in W$ because $W$ is $S$-invariant, therefore: $PBv=Bv$ and $BPv=Bv$.  If $v\in W'$ then $Pv=0$, hence $BPv=B\cdot 0=0$, and  (i) if $Bv\in W'$ then $PBv=0$.  (ii) if $Bv\in W$ then $PBv=Bv$ and this is where the problem occurs.  Any hints, ideas or counterexamples would be very helpful.