How to clear ostringstream
How do you clear a stringstream variable?
As the topic is there exist a homeomorphism between either pair of $(0, 1),(0,1],[0,1]$ I'm trying to figure out the name of a movie I saw on TV as a kid, in the mid-to-late 90s, in the US, in English, on daytime TV.  I remember it being kind of Starship Troopers-esque, but everyone had these glowing lights in their chests.  They glowed in different colored patterns, and I think it had something to do with whether you were attracted to someone or not (I was probably like 7 when I saw it, I didn't really understand the context of that part yet). Exposing database IDs - security risk? I have the following problem: two groups A and B.  The proportions of married and single are ($p_1$) and ($p_2$) respectively, and the standard deviations ($s_1$) and ($s_2$). The sample consists of  ($n_1$) A and  ($n_2$) B observations.  Now I want to test whether the proportions are equal. I use the following formula to compute the z-statistic:  z = $abs(p_1 - p_2) / \sqrt{ \frac{p_1(1-p_1)}{n_1} + \frac{p_2(1-p_2)}{n_2} }$  and test the hypothesis: h0: $p_1 \neq p_2$  An alternative approach I tried is to estimate the t-value based on the standard deviations (hence just comparing means), that is by the formula (assuming unequal variances):  t = $abs(p_1-p_2)/\sqrt{ s_1^2/n_1 + s_2^2/n_2 }$  My question are:    do you agree with my approach or; should it be two-sided or one-sided?   Thank you. How could a statement be true without proof? Function whose image of every open interval is $(-\infty,\infty)$ How to find a function from reals to reals such that the image of every open interval is the whole of R?  Is there one which maps rationals to rationals? Why do prisms work (why is refraction frequency dependent)? It is well known that a  can "split light" by separating different frequencies of light:    Many sources state that the reason this happens is that the  is different for different frequencies.  This is known as .  My question is about why dispersion exists.  Is frequency dependence for refraction a property fundamental to all waves?  Is the effect the result of some sort of non-linearity in response by the refracting material to electromagnetic fields?  Are there (theoretically) any materials that have an essentially constant, non-unity index of refraction (at least for the visible spectrum)? Warning or confirmation on new tag creation In retrospect of this , I would like to ask the community how they feel about a warning or confirmation (or just special highlighting) on new tag creation.  Everybody hates stock "are you sure?" confirmation, but a lot of tags get created by mistake (and then used ad nauseam).   For example, I think I might have created the  tag by accident. Assuming the right tag was , there would be two tags for c# 4.0, until they are made synonyms. With a warning, some accidental tags could be prevented. How do I close a connection early? I'm attempting to do an AJAX call (via JQuery) that will initiate a fairly long process. I'd like the script to simply send a response indicating that the process has started, but JQuery won't return the response until the PHP script is done running.  I've tried this with a "close" header (below), and also with output buffering; neither seems to work. Any guesses? or is this something I need to do in JQuery?  &lt;?php  echo( "We'll email you as soon as this is done." );  header( "Connection: Close" );  // do some stuff that will take a while  mail( 'dude@thatplace.com', "okay I'm done", 'Yup, all done.' );  ?&gt; How to format a USB flash drive? I am aware of the basics of evolutionary theory, however I don't understand how mutations can add genes over time.   Am I correct in thinking that creatures within the same species who mutate to have an additional gene in their genome would normally be infertile?  Or am I misunderstanding that?  Can someone explain the process of the creation of genetic material through evolution?  Citation to a decent academic paper or book on the matter would be appreciated too. Unwanted faint lines connecting dashed double line Building on the answer  by wrtlprnft, I have the following code     \documentclass[tikz,margin=1cm]{standalone}    \usetikzlibrary{decorations.markings}    \begin{document}    \begin{tikzpicture}         \tikzstyle{arrowed double line}=[             dashed, double distance between line centers=3pt,             postaction=decorate,             decoration={                 markings,                 mark=between positions 10pt and -10pt step 20pt with {                     \arrow[thin,yshift= 1.5pt,xshift=.8pt]{&gt;}                     \arrow[thin,yshift=-1.5pt,xshift=.8pt]{&lt;}                 },             },         ]         \draw[arrowed double line] (0,0) --  (1,2);     \end{tikzpicture} \end{document}   which produces this:    I am unhappy with the faint transverse lines between the dashes. I don't even know why tikz decides to draw them.  Is there a way to get rid of them?  Thanks in advance to all replies.  PS the same thing occurs at the caps of double solid lines How to render as only wireframe in Cycles? Ubuntu 18.04: switch back to /etc/network/interfaces Starting sometime around Ubuntu 18.04, the Ubuntu devs stopped using the classic /etc/init.d/networking and /etc/network/interfaces method of configuring the network and switched to some thing called . This has made a lot of people very angry and been widely regarded as a bad move. Is it possible to remove netplan and use the correct /etc/network/interfaces method for configuring the network? ETS() function, how to avoid forecast not in line with historical data? Prove that the additive groups of $\Bbb Z$ and $\Bbb Q$ are not isomorphic.    It is hard to create a map that will show homomorphism. How to connect to device via SSH over direct ethernet connection Show that $S$ is compact. Let $A \in M_n(\bf C)$ and let   $S=\{ A \in M_n(\bf C) : A=A ^*$ and  $\rho (A) \leq 1 \}$, $\rho(A)$ denotes spectral radius of $A$.     Show that $S$ is compact subset of $M_n(\bf C) \cong \bf C^{n^2} $ with usual topology.    $S$ is subset of $\bf O_n(C)$ which is compact so I think its enough to show that $S$ is closed.Please help. Are there any differences between URLs with and without "www" and "http://" Are there any differences among these addresses?     www.example.com http://www.example.com example.com The difference between an analogy and a metaphor? Many a time I've asked what the difference is between an analogy and a metaphor. I've asked it to my teacher, on internet sites, to my parents, so on and so forth. I got a different answer every time, and I never fully grasped what the difference is, so what is the difference?