Can I use only numbers for naming a CSS class
Is there a workaround to make CSS classes with names that start with numbers valid?
I have got myself a dxf which is built with units in the wrong scale. How do I upscale that in QGIS?   Note it does open in QGIS, just in the wrong map units and location. Can I request the code behind a research paper from the author? Representative point of a cluster with L1 distance The representative point of a cluster or cluster center for the k-means algorithm is the component-wise mean of the points in its cluster. The mean is chosen because it helps to minimize the within cluster variances (which is to say that it is minimizing within cluster squared Euclidean distance, since its the same). Now, when I want to use a different distance metric, like L1 (Manhattan distance), I would be minimizing the within cluster absolute deviations (if I choose to). I was looking at what the centers calculation would be like, because the mean won't reduce the new objective function, and I found this on the Matlab documentation of their kmeans function for the distance parameter     cityblock - Sum of absolute differences, i.e., the L1 distance. Each centroid is the component-wise median of the points in that cluster.   Now, how did they come up with the component-wise median? How does a median minimize absolute deviations? I tried different options to enable hibernate in Ubuntu 20.04 but nothing is working. How can I enable hibernate option in Ubuntu 20.04? What is the difference between local and global sequence alignments? There are a bunch of , and I don't want to get bogged down in the maths behind them as this not only between software but varies from software version to version.  There are two main divides in the programs; some use local alignments and others use global alignments. My question is threefold:   What are the fundamental differences between the two? What are the advantages and disadvantages of each? When should one use either a global or local sequence alignment? \pagestyle{empty} doesn't seem to work for page with \maketitle Displaying row/column of point in raster using QGIS? VLC will not install 14.04 I tried to watch a dvd and found that VLC was not installed. When I went to the Ubuntu software center I got this message when trying to install VLC. I do not know why. Here's the ouput:  "This error could be caused by required additional software packages which are missing or not installable. Furthermore there could be a conflict between software packages which are not allowed to be installed at the same time.  The following packages have unmet dependencies:  vlc: Depends: vlc-nox (= 2.1.4-0ubuntu14.04.1) but 2.1.4-0ubuntu14.04.1 is to be installed      Depends: libc6 (&gt;= 2.15) but 2.19-0ubuntu6.4 is to be installed      Depends: libfreetype6 (&gt;= 2.2.1) but 2.5.2-1ubuntu2.2 is to be installed      Depends: libgcc1 (&gt;= 1:4.1.1) but 1:4.9.1-0ubuntu1 is to be installed      Depends: libqtcore4 (&gt;= 4:4.8.0) but 4:4.8.5+git192-g085f851+dfsg-2ubuntu4 is to be installed      Depends: libqtgui4 (&gt;= 4:4.8.0) but 4:4.8.5+git192-g085f851+dfsg-2ubuntu4 is to be installed      Depends: libstdc++6 (&gt;= 4.6) but 4.8.2-19ubuntu1 is to be installed      Depends: zlib1g (&gt;= 1:1.2.3.3) but 1:1.2.8.dfsg-1ubuntu1 is to be installed"   Thanks in advance for any help. If I live in the US, for example, where current interest rates are practically nil, how can I take advantage of the fact that ? Understanding a particular evaluation of $\prod\limits_{n=2}^{\infty}\left(1-\frac{1}{n^3}\right)$ I'm having a hard time understanding the following evaluation of the infinite product  $$ \prod_{n=2}^{\infty}\left(1-\frac{1}{n^3}\right).$$ In particular, I don't understand how you go from line 2 to line 3. Here $\omega = -\frac{1}{2}+ i \frac{\sqrt{3}}{2}$, which is a primitive third root of unity.  $$\begin{align}\prod_{n=2}^{\infty}\left(1-\frac{1}{n^3}\right)  &amp;=\prod_{n=2}^{\infty}\frac{(n-1)(n^2+n+1)}{n^3} \\  &amp;=\lim_{m\to\infty}\frac{1}{m}\prod_{n=2}^m\frac{(n-\omega)(n-\omega^2)}{n^2} \\  &amp;=\lim_{m\to\infty}\frac{\Gamma(m+1-\omega)\Gamma(m+1-\omega^2)}{m(m!)^2\Gamma(-\omega)\Gamma(-\omega^2)(1-\omega)(1-\omega^2)(-\omega)(-\omega^2)} \\  &amp;=\frac{1}{3\Gamma(-\omega)\Gamma(-\omega^2)} \\ &amp;=\frac{\sin{\pi(-\omega)}}{3\pi} \\  &amp;=\frac{\cosh (\frac{\sqrt{3}\pi}{2})}{3\pi } \end{align}$$ EDIT: I think I'm starting to make sense out of this by writing out the terms. $$ \begin{align} \prod_{n=2}^{m} \frac{(n- \omega)(n-\omega^{2})}{n^{2}} &amp;= \frac{(2-\omega)(3-\omega) \cdots (m- \omega)(2-\omega^{2})(3-\omega^{2})\cdots (m- \omega^{2})}{2^{2} \cdot 3^{2} \cdot \cdots  \cdot m^{2}}  \\ &amp;= \frac{1}{(m!)^{2}} \frac{\Gamma(m+1-\omega)}{(1-\omega)(-\omega)\Gamma(-\omega)} \frac{\Gamma(m+1-\omega^{2})}{(1-\omega^{2})(-\omega^{2})\Gamma(-\omega^{2})} \end{align}$$ Now I have to figure out how to take the limit as $m \to \infty$. How do I write a good title? A good title helps your question get the attention it deserves.  What goes into a good title? How do you detect support for VML or SVG in a browser I'm writing a bit of javascript and need to choose between SVG or VML (or both, or something else, it's a weird world). Whilst I know that for now that only IE supports VML, I'd much rather detect functionality than platform.  SVG appears to have a few properties which you can go for: window.SVGAngle for example.  Is this the best way to check for SVG support?  Is there any equivalent for VML?  Unfortuntaly - in firefox I can quite happily do all the rendering in VML without error - just nothing happens on screen. It's quite hard to detect that situation from script. I'm new to latex, I'm thankful if someone can give me an example script to customize TOC that looks like  Chapter 1.XXXXXX                                                            (1-15)  1.1 Introduction 1.2 xxxxxxxx 1.3 xxxxxxxxxx 1.4 xxxxxxx ...............  Chapter 2.xxxxxxx  2.1 xxxxx ......                                                           (16-30)  because the (default) TOC appears to be very large for my book, since it arranges the section name row-by-row. Is there anything in the physics that enforces the wave function to be $C^2$? Are weak solutions to the Schroedinger equation physical? I am reading the beginning chapters of Griffiths and he doesn't mention anything. What are beginner’s books on typography? How to 'sum' a standard deviation? I have a monthly average for a value and a standard deviation corresponding to that average. I am now computing the annual average as the sum of monthly averages, how can I represent the standard deviation for the summed average ?  For example considering output from a wind farm:  Month        MWh     StdDev January      927     333  February     1234    250 March        1032    301 April        876     204 May          865     165 June         750     263 July         780     280 August       690     98 September    730     76 October      821     240 November     803     178 December     850     250   We can say that in the average year the wind farm produces 10,358 MWh, but what is the standard deviation corresponding to this figure ? Possible Duplicate:             In the itemize environment, how do I use the ampersand symbol &amp; without LaTeX trying to use it as a command? Are Groups or Sketchup-like components feasible in Blender? Apart from testing it myself, I've seen a few posts  and , including from Sketchup users like me, sort of circle around this topic but never ask this question directly. How can I overcome these problems in DupliGroups or Collection Instances?  moving its origin seems to require moving to World origin (and using up a layer for clarity) &lt;=&gt; linked meshes have their own local origin which I can move data around in Edit Mode (easy enough)  It is impractical to link up DupliGroup data to previously created meshes because the origin mismatch as above, and the mesh data that remains in it and needs to be deleted somehow  Linked meshes don't have the above two problems (can be 'blocked in' and then detailed up all at once) but I can't add objects to them, only faces. Say I'd like to add handles as linked meshes, because handles are used elsewhere in the model too.    How feasible would it be to make a linked object type with deeper hierarchy? Say an object that would look at its children and simply make every other instance have the same children. It would also mean dragging and dropping in outliner would be the simplest way to manage it by the looks of it. Finding all homomorphisms between $\mathbb{Z}/m\mathbb{Z}$ and $\mathbb{Z}/n\mathbb{Z}$ I want to find all group homomorphisms $\varphi: \mathbb{Z}/ m \mathbb{Z} \to \mathbb{Z}/n\mathbb{Z}$, with $m$ and $n$ natural numbers.  Clearly $\varphi(0)=0$ since the identity in $\mathbb{Z}/m\mathbb{Z}$ must map to the identity in $\mathbb{Z}/n\mathbb{Z}$, and it follows that $m \varphi(1)=0$, so is $mx \equiv 0 \bmod n$?  This as far as I get. How can I find all the homomorphisms? First post and late answer review queues always empty?