console log is below.  -> d3.select("#node1")  &lt;- qa {_groups: Array[1], _parents: Array[1]}  -> d3.select("#node1.1")  &lt;- Uncaught DOMException: Failed to execute 'querySelector' on 'Document': '#node1.1' is not a valid selector.(…)  -> $("#node1")  &lt;- [​sdsdg​​]  ->  $("#node1.1")  &lt;- []  -> document.getElementById("node1")  &lt;- ​sdsdg​​  -> document.getElementById("node1.1")  &lt;- ​asfas​​  element #node1 has nothing problem. #node1.1 is working well by native javascript but jquery(3.0.0) and d3(4.1.1)  I don't know why. could I know what happened to #node1.1?  I could copy element selector by chrome developer tool. the result is      element #node1 -> #node1      element #node1.1 -> #node1\2e 1
When creating the id attributes for HTML elements, what rules are there for the value?
I don't understand philosophy very well, and so I am wondering whether you can "prove" anything in philosophy. It always seems you can go a layer down, and find another question, almost endlessly until you get to the question of "why/how/are we here?"  Can you prove, absolutely, and 100% that something is true, in the field of philosophy? Is it bad behavior to add filler words such as "so", "um" in business speak? Let $Z_i,Z_2,\ldots$ be IID Random Variables with density $f$. Suppose that $P(Z_i&gt;0)=1$ and that $\lambda=\lim_{x \to 0+} f(x)&gt;0$. How can I show that $X_n=n \times \min\{Z_i\}$ has a limiting exponential distribution with mean$1/\lambda$?  I know that the CDF of the first order Statistic is for $t&gt;0$  $$F_{min \{ Z_i \}} (t)= 1- \left[ 1-F(t) \right]^{n}$$  Convergence in distribution requires that $F_n (t) \to F(t)$ for some distribution function $F$ but I cannot quite take the limit of the above, with $t$ replaced by $x/n$, as the distribution is not known. I guess I have to insert the second piece of information somewhere but I do not recognise where.  Could you please give me a hint or two?  Thank you. What happened to Saruman after he was knifed by Grima? InputStream returning NullPointerException (Java) Parsing DateTime on Localized Systems Presently, how much information can a quantum computer store, in how many qubits? What restrictions are there and how does it vary across realizations (efficiency of data storage, ease of reading and writing, etc)? If $\lambda$ is an eigenvalue of $A^2$, then either $\sqrt{\lambda}$ or $-\sqrt{\lambda}$ is an eigenvalue of $A$ $A$ is an $n\times n$ matrix of complex numbers. Prove that if $\lambda$ is an eigenvalue of $A^2,$ then $\sqrt{\lambda}$ or $-\sqrt{\lambda}$ is an eigenvalue of $A.$    If $\lambda$ is an eigenvalue of $A^2,$ we have $\lambda\alpha=A^2\alpha$ for some $\alpha.$ Then how can we find a $\beta$ s.t. $\sqrt{\lambda}\beta=A\beta?$ How can I apply an effect when a player left-clicks/right-clicks with an item in hand? biblatex: per-entry language switching According to biblatex manual (p.24), the hyphenation field in a bib-entry switches language on per-entry basis:     hyphenation field    The language of the bibliography entry. The identifier must be a language name   known to the babel package. This information may be used to switch hyphenation   patterns and localize strings in the bibliography.   This functionality seemed to not work. I just used an example of bib base that comes with biblatex documentation to print the entire bibliography.   \documentclass[a4paper]{article} \usepackage[T1]{fontenc} \usepackage[german,american]{babel} \usepackage{csquotes} \usepackage[style=numeric,backend=biber]{biblatex} \addbibresource{biblatex-examples.bib} \begin{document} \nocite{*} \printbibliography \end{document}   The bibliography contains few entries in German. However in the printed list of references they are formatted with english strings.     [8] Averroes. Drei Abhandlungen über die Conjunction des separaten Intellects   mit dem Menschen. Von Averroes (Vater und Sohn), aus dem   Arabischen übersetzt von Samuel Ibn Tibbon. Ed. and trans. by J. Hercz.   Berlin: S. Hermann, 1869.   Per-entry language switching is provided by the  bundle of bst style for BibTeX. Looking through biblatex internal code, I've got an impression that biblatex needs major re-implementation in order to provide similar functionality. Or am I wrong? A local IP address (RFC 1918) on my network that is not … local I've noticed an IP address today on my network (192.168.15.1) which when visited actually goes to a page that has a router webconfig page (Not my router)  The puzzling thing is that i tried traceroute 192.168.15.1 which said that the distance between me and that host is 9 hops, whereas the distance between me and any other computer on my home network is 2 hops away (My computer --> Router --> Host)   Can someone please explain what's going on here ?  tracert output:  Tracing route to 192.168.15.1 over a maximum of 30 hops    1    &lt;1 ms    &lt;1 ms    &lt;1 ms  192.168.1.1   2    47 ms    51 ms    49 ms  [163.121.171.123]   3     *        *        *     Request timed out.   4   128 ms     *        *     163.121.211.134.dnet.net [163.121.211.134 ]   5     *      134 ms   126 ms  10.37.242.18   6    94 ms    90 ms    95 ms  10.35.2.157   7   178 ms   254 ms   206 ms  10.32.8.107   8    85 ms    57 ms   318 ms  10.35.0.186   9   215 ms   241 ms   230 ms  192.168.15.1  Trace complete. How do you prove that these four definitions of the operator norm are equivalent? $$\begin{align*} \lVert A\rVert_{\mathrm{op}} &amp;= \inf\{ c\;\colon\; \lVert Av\rVert\leq c\lVert v\rVert \text{ for all }v\in V\}\\ &amp;=\sup\{ \lVert Av\rVert\;\colon\; v\in V\text{ with }\lVert v\rVert\leq 1\}\\ &amp;=\sup\{\lVert Av\rVert\;\colon\; v\in V\text{ with }\lVert v\rVert = 1 \}\\ &amp;=\sup\left\{ \frac{\lVert Av\rVert}{\lVert v\rVert}\;\colon\; v\in V\text{ with }v\neq 0\right\}. \end{align*}$$ Proof by induction: $\sum\limits_{i=1}^{n} \frac{1}{n+i} = \sum\limits_{i=1}^{n} \left(\frac{1}{2i-1} - \frac{1}{2i}\right)$ How can the following be proved by induction?  $$\sum\limits_{i=1}^{n} \frac{1}{n+i} = \sum\limits_{i=1}^{n} \left(\frac{1}{2i-1} - \frac{1}{2i}\right)$$ I am out of ideas after practicing for a while:  $$\frac{1}{n+1}+\frac{1}{n+2}+\dots+\frac{1}{2n}=\left(1-\frac{1}{2}\right)+\left(\frac{1}{3}-\frac{1}{4}\right)+\dots+\left(\frac{1}{2n-1}-\frac{1}{2n}\right) $$  Does this involve telescoping series? Converting Older United States Dollar Bills mysql_fetch_array does not retrieve all rows If you click on the Stack Exchange menu or the inbox menu or the achievements/reputation menu, you can then move the mouse between those three menus without any additional clicks.  This behaviour does not appear to be applying to the Winterbash menu (or the "help" menu for that matter, but that's on the other side of the bar).  Could we get this sorted, since otherwise the behaviour is a little inconsistent, with extra clicking on a menu bar where in all other circumstances clicking would close the menu! Geometric meaning of the determinant of a matrix Proving the universal mapping property for polynomial rings I'm looking to make a "Drop Folder" in a windows shared drive that is accessible to everyone. I'd like files to be deleted automagically if they sit in the folder for more than X days.  However, it seems like all methods I've found to do this, use the last modified date, last access time, or creation date of a file.  I'm trying to make this a folder that a user can drop files in to share with somebody. If someone copies or moves files into here, I'd like the clock to start ticking at this point. However, the last modified date and creation date of a file will not be updated unless someone actually modifies the file. The last access time is updated too frequently... it seems that just opening a directory in windows explorer will update the last access time.  Anyone know of a solution to this? I'm thinking that cataloging the hash of files on a daily basis and then expiring files based on hashes older than a certain date might be a solution.... but taking hashes of files can be time consuming.  Any ideas would be greatly appreciated!  Note: I've already looked at quite a lot of answers on here... looked into File Server Resource Monitor, powershell scripts, batch scripts, etc.  They still use the last access time, last modified time or creation time... which, as described, do not fit the above needs. Combinatorial proof of summation of $\sum\limits_{k = 0}^n {n \choose k}^2= {2n \choose n}$ I was hoping to find a more "mathematical" proof, instead of proving logically $\displaystyle \sum_{k = 0}^n {n \choose k}^2= {2n \choose n}$.  I already know the logical Proof:  $${n \choose k}^2 = {n \choose k}{ n \choose n-k}$$  Hence summation can be expressed as:  $$\binom{n}{0}\binom{n}{n} + \binom{n}{1}\binom{n}{n-1} + \cdots + \binom{n}{n}\binom{n}{0}$$  One can think of it as choosing $n$ people from a group of $2n$  (imagine dividing a group of $2n$ into $2$ groups of $n$ people each. I can get $k$ people from group $1$ and another $n-k$ people from group $2$. We do this from $k = 0$ to $n$.