I would like to have a brace in a tikz picture. However, when I process the file   \documentclass{amsart} \usepackage{tikz} \usetikzlibrary{decorations} \usetikzlibrary{decorations.text} \begin{document} \begin{tikzpicture}[scale=8]   \def\C{(0.688191,0)}   \def\D{(0.688191, 0.1844)}   \def\E{(0.830424, 0.1844)}   \draw[decorate,decoration=brace] \C -- \D; \end{tikzpicture} \end{document}   I get   ! Package pgfkeys Error: I do not know the key '/pgf/decoration/\pgfkeyscurrent name ' and I am going to ignore it. Perhaps you misspelled it.  See the pgfkeys package documentation for explanation. Type  H &lt;return&gt;  for immediate help. ...                                      l.10 \draw[decorate,decoration=brace]                                         \C -- \D;  help. Pretend that you're Hercule Poirot: Examine all clues, and deduce the truth by order and method.   I saw similar questions  and  and , but the answers to them don't seem to help me. I would appreciate your help.
I have TeX Live 2013 installed via MacTeX on my Snow Leopard laptop.  I copied the following code from page 247 of version 2.10 of pgfmanual:  \documentclass[a4paper,12pt]{report} \usepackage{tikz} \usetikzlibrary{decorations}  \begin{document}  \begin{tikzpicture} \node (a) {A}; \node (b) at (2,1) {B}; \draw (a) -- (b); \draw[decorate,decoration=brace] (a) -- (b); \draw[decorate,decoration={brace,mirror},red] (a) -- (b); \draw[decorate,decoration={brace,mirror,raise=5pt},blue] (a) -- (b); \end{tikzpicture}  \end{document}   Yet somehow I get this error:  ./Untitled2.tex:11: Package pgfkeys Error: I do not know the key '/pgf/decorati on/brace' and I am going to ignore it. Perhaps you misspelled it.  See the pgfkeys package documentation for explanation. Type  H &lt;return&gt;  for immediate help.  ...                                                l.11 \draw[decorate,decoration=brace]                                       (a) -- (b); ?    Is this a bug?
Clipping LAS data using shapefile polygons and open source software? I am trying to clip or filter lidar files (.las, .xyz) using a shapefile that contains multiple polygons.  Is there open source software that can do this spatial operation?  My .las files are enormous, and I should say that I am very new to DEM data and analysis so any help would be very welcome. How do you change age settings on ROBLOX? How do you set your age settings on ROBLOX if you accidentally set to under 13? I accidentally put 2008 instead of 1998 in the sign up section. Is there any way to change this, as in settings, age settings are greyed out. Navier-Stokes system In my experience, input type="text" onchange event usually occurs only after you leave (blur) the control.  Is there a way to force browser to trigger onchange every time textfield content changes? If not, what is the most elegant way to track this “manually”?  Using onkey* events is not reliable, since you can right-click the field and choose Paste, and this will change the field without any keyboard input.  Is setTimeout the only way?.. Ugly :-) My boot is horribly slow, and I don't know why.  $ systemd-analyze  Startup finished in 10.975s (kernel) + 49.732s (userspace) = 1min 708ms $ systemd-analyze blame           34.971s apt-daily.service          20.590s snapd.refresh.service          17.113s grub-common.service          16.033s apport.service          16.027s networking.service          15.894s ondemand.service          15.860s irqbalance.service          15.655s speech-dispatcher.service          11.695s ModemManager.service           9.772s accounts-daemon.service           8.626s NetworkManager-wait-online.service           8.058s systemd-logind.service           8.053s bluetooth.service           7.944s gpu-manager.service           7.896s alsa-restore.service           7.892s pppd-dns.service           7.882s rsyslog.service           7.860s avahi-daemon.service           7.844s dev-sda1.device           7.842s systemd-user-sessions.service           7.648s lightdm.service           7.610s teamviewerd.service           6.445s apparmor.service   Also, during boot-up, I see a message that says something like:  device descriptor read/all, error -62 ata1 softreset failed (device not ready) #most of the times error loading journal #(sometimes) Test WP failed, assume Write Enabled Asking for cache data failed     #most of the times Assuming drive cache: write through   apt-daily.service slows the boot the most. Any idea on how to tackle that?  I have Ubuntu MATE 16.04. Flirtatious Primes Here's a possibly interesting prime puzzle. Call a prime $p$ flirtatious if the sum of its digits is also prime. Are there finitely many flirtatious primes, or infinitely many? food safety regarding re freezing twice cooked chicken Spoilers for A Storm of Swords / Season 4 episode 2 "The Lion and the Rose".  At the Purple Wedding,      Littlefinger and Lady Olenna Tyrell   perform their plan of      poisoning King Joffrey.   A short summary of their plan:  Littlefinger orders Ser Dontos Hollard to give Sansa Stark a beautiful silver hairnet adorned with amethysts. At least some of the amethysts are actually strangler crystals in disguise. Ser Dontos also, still under orders of Littlefinger, urges Sansa to wear the hairnet at the wedding, which she then does. At the wedding, when Lady Olenna greets Sansa, she fusses her hairnet a bit, while secretly taking one of the strangler crystals. Later, during the wedding, Lady Olenna puts the crystal in Joffrey's royal cup, poisoning him.  But why was their plan so complicated? Why couldn't Lady Olenna just bring a strangler crystal with her to the wedding (as suggested in )?  Then they wouldn't depend on Ser Dontos and Sansa who could unknowingly have done something to prevent the success of the plan.  The only reason that I could think of, is Littlefinger and Lady Olenna plan for Sansa (and Tyrion as her husband with her) to take the blame for Joffrey's death.  They put the crystals on her person, so that upon examination it would clearly show that Sansa had the murder weapon on her. But Littlefinger had a plan he did not tell Lady Olenna, namely rescuing Sansa during the chaos ensuing the murder (and thereby leaving Tyrion behind as the only accused).  Is there anything confirming or debunking this theory? If my theory doesn't hold up, is there another explanation for why the plan was so needlessly complicated? Friend can't join world I've always had this question about the pronunciation of Sean.  Is Sean a word from another language? Is it actually not pronounced Shawn and instead it's some sound between Shawn and Seen? Also, why isn't it pronounced as Sawn instead of Shawn, when the word Sean doesn't even have the letter 'h' in it to get that -sh sound?  Bottom line is, why is Sean pronounced Shawn instead of Seen? What is crop factor and how does it relate to focal length? "He saw it stop and his son get out" I have been reading Men With Brooms for a few days. I read a sentence which did not make any sense to me, so I landed here to get some help on it. I have pasted the sentence from the novel. Please go through it and let me know your valuable feedback on it.  An excerpt from the novel (Men With Brooms: A Sweeping Epic, paperback 2002, a novelization by Diane Baker Mason):     Gordon was about to walk away from the Impala when he saw it stop and his son get out. So it was real the boy had come.   As per my opinion it should have been:     Gordon was about to walk away from the Impala when he saw it stopped and his son got out. So it was real the boy had come.   I have two questions here:   Why did the writer use stop and get instead of stopped and got? As she is telling us a story which happened in the past. Let's say the writer is telling us her mind's situation and she used the present tense for it but why did she use stop and get instead of stops and gets? Can you dispel a magic effect you can't perceive? Discussions about Dispel Magic seem to imply that as long as you can perceive a magic effect in range of the spell, you can try and dispel it.   See  and  from @Miniman:      knowing where it is means that you know where it is. This allows you to use spells like Dispel Magic to remove its invisibility.   But what if you can't perceive it?  Two scenarios come in mind:   In combat, an evil wizard casts Invisibility on himself, walks away from the fray and uses the hide action on his next turn. Since PCs know/assume/deduce he's invisible and certainly in range of the spell, can one use Dispel Magic to end the spell? PCs enter a 80'&times;80' room. Can one declare: "I dispel any Invisibility spell in range", thus revealing one (the closest?) invisible enemy in the room?   What's enough to enable a caster to cast Dispel Magic on a magic effect:    perceiving (seeing, hearing, smelling, etc.) it? knowing/assuming/deducing it's there? or merely suspect/predict it? Is it safe to have laptop turned on 24/7? I have an old HP dv7-7210sp laptop and I want to use it as a server. Is it safe to have it turned on 24/7? The server will be used with Nextcloud to backup my data.  Should I remove the battery from the laptop or keep it as a backup power source?  Also, is it safe to run HDD 24/7 or should I enable APM so it spins down after some time of inactivity?  Can the laptop burn if I leave it running? My book gives the following definition:     Let $(M,d)$ be a metric space, and let $\mathcal{T}$ be the collection of all subsets of $M$ that are open in the metric space sense...  $\mathcal{T}$ is called the topology generated by d   Then it later says to prove things about two different metrics generating the same topology. However I'm very confused about what all this means.   When I read "all subsets," I think of the theorem that says a set with $n$ elements will have $2^n$ subsets. (ex. all the subsets of $\{1,2,3\}$ are $\{\emptyset, \{1\},\{2\},\{3\},\{1,2\},\{1,3\},\{2,3\},\{1,2,3\} \}$). So I think "all subsets that are open" would be like, If M is the set (1,5), then an open subset would be any set $(a,b)$ where $1&lt;a&lt;b&lt;5$, and then all subsets would be all possible union combinations of these "$(a,b)$" sets.     Its seems to me that metrics have nothing to do with subsets. Clearly there is something i'm not understanding. Please Help me.   It would be very enlightening, if someone could give me some simple examples of 1 set and 2 metrics generating two different typologies. Show that $\lim\limits_{a \to 0^+} \int^1_0 ax^{a−1}f(x)dx=f(0)$. Suppose $f$ is Riemann integrable on $[0,1]$ and continuous at 0. Show that $$\lim\limits_{a \to 0^+} \int^1_0 ax^{a−1}f(x)dx=f(0).$$   Can anyone share some insight on this one? I have no idea where to begin. Maybe a substitution? Application of inverse function theorem for several variable functions Let $f:\mathbb{R}^2\rightarrow \mathbb{R}^2$ be continuously differentiable, and assume $Df(x)$ is invertible for all $x\in \mathbb{R}^2$. Also for any compact $K$ in $\mathbb{R}^2$, $f^{-1}(K)$ is compact. prove $f$ is onto.  My Work:  This is an application of inverse function theorem because it satisfies the hypothesis of this thoerem. So $A=f(\mathbb{R}^2)$ is open in $\mathbb{R}^2$. So, $A^c$ is closed. Afterwards I was stuck. please give me a hint. AUC and class imbalance in training/test dataset I just start to learn the Area under the ROC curve (AUC). I am told that AUC is not reflected by data imbalance. I think it means that AUC is insensitive to imbalance in test data, rather than imbalance in training data.  In other words, only changing the distribution of positive and negative classes in the test data, the AUC value may not change much. But if we change the distribution in the training data, the AUC value may largely change. The reason is that the classifier cannot be learned well. In this case, we have to use undersampling and oversampling. Am I right? I just want to make sure my understanding on AUC is correct. Where can I find information about upcoming special issues in a field of study? Forcing smoothness of regression coefficients