What is the difference between the horror and thriller genres?
Is there a criterion to differentiate "thriller" from "horror"?
idempotents acting as local identities Let $R$ be a ring with unity (not necessarily commutative) and $I$ an ideal of $R$.  Suppose that for every element $a \in I$ there exists an element $c\in I$ such that $ac=a$. Note that $c$ is related to $a$. Now we have the following question:  Can we say that  for every element  $a\in I$ there exists an idempotent element $c\in I$ such that $ac=a$?    Of course we have many examples such that the answer is true for them but in general  we don't know. How can I find $f(0)$, $f'(0)$, and $f'(x)$ given that  $f(x+y)=f(x)+f(y)+x^2y+xy^2$  and  $\lim_{x\to0}\frac{f(x)}{x}=1$. I was writing some Unit tests last week for a piece of code that generated some SQL statements.  I was trying to figure out a regex to match SELECT, INSERT and UPDATE syntax so I could verify that my methods were generating valid SQL, and after 3-4 hours of searching and messing around with various regex editors I gave up.  I managed to get partial matches but because a section in quotes can contain any characters it quickly expands to match the whole statement.  Any help would be appreciated, I'm not very good with regular expressions but I'd like to learn more about them.  By the way it's C# RegEx that I'm after.  Clarification  I don't want to need access to a database as this is part of a Unit test and I don't wan't to have to maintain a database to test my code. which may live longer than the project. How can I let people join my minecraft server from diffrent versions? What steps must an educational institution wanting to recruit good faculty take? There is a cycle in the academia:    Good doctorates from top universities invariably join other top universities as faculty members.  Good students aspire to study in top universities under excellent faculty members.   Suppose a new educational institution or department springs up and desires to set up a top-quality group, how does it break into this cycle? I suppose this could take some years, but is money-power the only thing that could be wielded by the institute to achieve its end? How do I register a custom URL protocol in Windows? How do I register a custom protocol with Windows so that when clicking a link in an email or on a web page my application is opened and the parameters from the URL are passed to it? Prove that if $p \equiv 3 \pmod{4}$ then $x^2+y^2 \not \equiv 0 \pmod{p}$ Let $x$ and $y$ be integers not congruent to $0$ modulo $p$ where $p$ is a prime. Prove that if $p \equiv 3 \pmod{4}$ then $x^2+y^2 \not \equiv 0 \pmod{p}$.   I thought about proving this algebraically and by contradiction. So we say $x^2+y^2 = pz$ and have to show this is impossible. Suppose $\sum_{n=1}^\infty \frac{1}{n} = S$ where $S$ is finite.  Then  $$S =\sum_{n=1}^\infty \frac{1}{n}= \sum_{n=1}^\infty \frac{1}{2n-1} + \frac{1}{2n} &gt; \sum_{n=1}^\infty \frac{1}{2n} + \frac{1}{2n} = S$$  which is a contradiction.  Is this valid? Contour integral for $x^3/(e^x-1)$? What contour and integrand do we use to evaluate $$ \int_0^\infty \frac{x^3}{e^x-1} dx $$  Or is this going to need some other technique? Is mass converted into energy in exothermic chemical/nuclear reactions?  My (A Level) knowledge of chemistry suggests that this isn't the case. In a simple burning reaction, e.g.   $$\mathrm{C + O_2 \to CO_2}$$  energy is released by the $\mathrm{C-O}$ bonds forming; the atoms lose potential energy when they pull themselves towards each other, in the same way that a falling object converts GPE to KE. There are the same number of protons, electrons etc. in both the reactants and products. I would have assumed that this reasoning extends to nuclear fission/fusion as well, but one physics textbook repeatedly references very small amounts of mass being converted into energy in nuclear reactions.  So I just wanted to know if I was wrong about either of these types of reactions, and if so, what mass is lost exactly? Is any aspect of the supernatural testable? What level of proof is possible for the supernatural? How do I delete/remove a shell function? I have done this:  $ z() { echo 'hello world'; }   How do I get rid of it? Find a tangent to two quadratic bezier curves I have two quadratic bezier curves and I want to find whether they have a common tangent, and if so where it is.  If the first bezier is defined by points $(x_1, y_1)$, $(x_2, y_2)$, $(x_3, y_3)$, then the points on the curve have coordinates:  $x = (x_1 - 2x_2 + x_3)t^2 + (2x_2 - 2x_1)t + x_1 \\ y = (y_1 - 2y_2 + y_3)t^2 + (2y_2 - 2y_1)t + y_1$  Or to simplify things:  $x = A_xt^2 + B_xt + C_x \\ y = A_yt^2 + B_yt + C_y$  Likewise, I can get an equation for the second bezier:  $x = D_xs^2 + E_xs + F_x \\ y = D_ys^2 + E_ys + F_y$  The gradient of the tangent, $m$, to the first curve at $t$ is $\dfrac{2A_yt + B_y}{2A_xt + B_x}$,  which must be equal to the tangent to the second curve at $s$, $\dfrac{2D_ys + E_y}{2D_xs + E_x}$.  So $m = \dfrac{2A_yt + B_y}{2A_xt + B_x} = \dfrac{2D_ys + E_y}{2D_xs + E_x}$  Which I rearranged to get:  $t = \dfrac{2(B_yD_x - D_yB_x)s + B_yE_x - B_xE_y}{4(A_xD_y - A_yD_x)s + 2(A_xE_y - A_yE_x)}$  The gradient of the tangent is also equal to the difference in the y-coordinates over the difference in x-coordinates:  $m = \dfrac{D_ys^2 + E_ys + F_y - (A_yt^2 + B_yt + C_y)}{D_xs^2 + E_xs + F_x - (A_xt^2 + B_xt + C_x)}$  But that's as far as I got. The algebra looks too messy from here. Can anyone solve this, or is there a better approach? Open a window on a remote X display (why "Cannot open display")? Once upon a time,  DISPLAY=:0.0 totem /path/to/movie.avi   after ssh 'ing into my desktop from my laptop would cause totem to play movie.avi on my desktop.  Now it gives the error:   No protocol specified Cannot open display:    I reinstalled Debian squeeze when it went stable on both computers, and I guess I broke the config.   I've googled on this, and cannot for the life of me figure out what I'm supposed to be doing.   (VLC has an HTTP interface that works, but it isn't as convenient as ssh.)  The same problem arises when I try to run this from a cron job. Difference between Can/Could: "Can (could) you sell your old computer to me?" What is difference between  Could you sell your old computer to me, seeing (that) you have no use for it. Can you sell your old computer to me, seeing (that) you have no use for it.  Can I use either one of them? Which one is grammatically correct or if both are, what is the difference in meaning? Suppose $p$ is a prime number such that $(p-1)/4$ and $(p+1)/2$ are also primes. Show that $p=13$ Suppose $p$ is a prime number such that $(p-1)/4$ and $(p+1)/2$ are also primes. Show that $p=13$.   My approach:   Since $p$ is prime, it is of the form $6k+1$ or $6k-1$. Now if $p$ is of the form $6k-1$ then $(p+1)/2 = 3k$ which is not possible as $3|3k$.   So $p$ is of the form $6k+1$. Now $(p-1)/4 = 3k/2$ so $2\mid k$. So $p$ is of the form $12k+1$. But now, how to prove $k=1$?  Please help! Should I use the past tense with did? Should I use the past tense with did? For example, I was to say:     The important question is: Did they knew what it means or not?   Or should I say:     The important question is: Did they know what it means or not?   In other words: Should I use past tense with did?  I looked at this:    but it didn't really answer my question. Can a curve object modifier created geometry be used as boolean factor This question is related to .  Let me use an exemple to illustrate what I mean.  We've created a text object (made of curves). It can't be used in a boolean modifier as it won't appear in the list of usable objects in the modifier because it's a curve object.  But if we add a remesh modifier on the text, geometry is created from the shape.  The object could be used as boolean if we convert it to mesh. The remesh can't be applied on curve object.  My question is : Can we dynamicaly use the remesh modifier created geometry as real geometry or make the boolean modifier consider the text modified object as a real mesh?  The idea behind this is to be able to change the text (or any curve 3D shape) without having to make it a real mesh.  (don't hesitate to edit my poor english to make it understandable :) ) Is it safe to set xp_cmdshell value 1? I need to use xp_cmdshell in one of SQL job.So is it safe to reconfigure xp_cmdshell to 1 or can i set value 1 in the starting of SQL statements and set it back to 0 in the end of SQL Statement ? What is a "closed" or "duplicate" question?