I have had a few problem with exim4 and various phone mail clients (Windows Phone in particular) that seem to result from bad mail clients together with GnuTLS. I'd like to recompile exim4-daemon-heavy to use OpenSSL to see if that helps anything.  Now, I've gotten used to debian's packaging system and am unsure on how to do this. I've downloaded the exim4 source using apt-get source exim4. I then edited the file Debian/rules to uncomment OpenSSL = 1.  Then I tried make, but was told that I need to copy the template src/EDITME to Local/Makefile and edit it to my taste. My taste would be a drop-in replacement for the existing and running exim4-daemon-heavy, just using OpenSSL. And here I am stumped as there are quite a lot of options there and I don't like to break my email setup more than neccessary.  So... what can I do to make this test?
I want to create a DEB file manually. I would like to just provide a folder which contains data to install, and a script to be executed after installation.  Is this possible?
Let $A, B$ be subsets of a metric space $X$. If $A$ is compact and $B$ is closed, show that the distance between $A$ and $B$ is achieved.   Attempt at a proof:    Let $A$ be compact and $B$ be closed. Let $m=d(A,B)=\inf_{b\in B} d(A,B)$. Then, there are two possibilities: (a) $\exists b\in B$, $d(a,b)=m$. If this is the case, we're done. (b) $\forall b\in B$, $d(a,b)&gt;m$. In this case,     there exists a sequence $\{b_n\}\subseteq B:$ $d(a,b_n)\rightarrow m$ as $n\rightarrow\infty$ by definition of infinum. Then there exists a subsequence $\{b_{n_k}\}$: $d(b_{n_1},a)&gt;d(b_{n_2},a)&gt;...$ which is monotonic decreasing. Then note that $d(b_{n_k},a)&lt;d(b_{n_1},a)&lt;\infty$. So it's a bounded sequence. Now I want to show that it has a convergent subsequence that converges to $b\in B$ and then I want to do the same for $A$. And then finally to show that $d(a,b)=m$ in fact. Any clues to how to get there? What is the C# Using block and why should I use it? What is the purpose of the Using block in C#? How is it different from a local variable? Convert list of ints to one number? The  that is defined as $Y_{t} = Y_{t-1} + e_t$, where $e_t$ is white noise. Denotes that the current position is the sum of the previous position + an unpredicted term. You can prove that the mean function $\mu_t = 0 $, since $$E(Y_{t}) = E(e_1+ e_2+ ... +e_t) = E(e_1) + E(e_2) +... +E(e_t) = 0 + 0 + \cdots + 0$$ But why is it that the variance increases linearly with time? Does this have something to do with it's not “pure” random, since the new position is very correlated with the previous one? EDIT: Now I have a much better understanding by visualizing a big sample of random walks, and here we can easily observe that the overall variance does increase over time,  and the mean is as expected around zero. Maybe this was trivial after all, since in the very early stages of the time series (compare time = 10 with time = 100) the random walkers have not had yet the time to explore as much. Can I ever go wrong if I keep thinking of derivatives as ratios? Why are some of my screen-recording/capturing/sharing applications (or app features) not working in Ubuntu 17.10 (and later releases)? After upgrading to Ubuntu 17.10 I noticed some of my screencasting applications are not working, for example screencasting tools like SimpleScreenRecorder and vokoscreen. ()  Also I noticed features like screenshot from GIMP is not working properly, producing blank screenshots (). Shutter too is producing glitchy screenshots ().  Screen-sharing option on Skype is also not working ().  The issue occurs sometimes on later Ubuntu releases too.  Why is this happening and how do I fix this? How to increase ping time/network connection latency on Windows? I need to permanently increase network latency in approximately 100ms, without losing packets.  Reason: On a certain server and internet game my ping is too much lower than the other people playing it. I have 15ms, when average is 150ms which gives me cheater-like advantages.  So also out of curiosity I'm looking for ways to increase my ping while keeping connection stable. What are my options if any?  I thought about VPN services, but it seems like a bad option since games use UDP?  Is there any router/software that would assist me on this?  I'm on windows. Show that $ a，b, \sqrt{a}+ \sqrt{b} \in\mathbb Q \implies \sqrt{a},\sqrt{b} \in\mathbb Q $ Inspired by , I was wondering if there is a simple logical argument to   Show that $ a,b, \sqrt{a}+ \sqrt{b} \in\mathbb Q  \implies  \sqrt{a},\sqrt{b} \in\mathbb Q $  Note that the original link is using a computational method, where as I am looking for a simple logical argument.  I tried (unjutifiably) to argue that if some of two square roots is rational then each one is rational, this is a different than the (incorrect) argument that if sum of two algebraic numbers is rational then each one is rational ( counter example $a=1-\sqrt{2},b= 1+\sqrt{2} $) When umpire change the cricket ball, was the old ball thrown as waste or keep for reuse? $n,a,b \mathbb \in \mathbb Z^+$ , such that $n\mid a^n-b^n$ ; to show $n\mid \frac {a^n-b^n}{a-b}$ Limit of $\lim_{n\rightarrow \infty} \sum^{n}_{i=1} \frac{1}{\sqrt {n^2 +i} }$ In C, is it possible to forward the invocation of a variadic function? As in,  int my_printf(char *fmt, ...) {     fprintf(stderr, "Calling printf with fmt %s", fmt);     return SOMEHOW_INVOKE_LIBC_PRINTF; }   Forwarding the invocation in the manner above obviously isn't strictly necessary in this case (since you could log invocations in other ways, or use vfprintf), but the codebase I'm working on requires the wrapper to do some actual work, and doesn't have (and can't have added) a helper function akin to vfprintf.  [Update: there seems to be some confusion based on the answers that have been supplied so far. To phrase the question another way: in general, can you wrap some arbitrary variadic function without modifying that function's definition.] Let $X_n$ be iid random variables with $P(X_n=(-1)^kk)=\dfrac{C}{k^2\log k}$ for all $k\geq 2$. Here $C$ is just a constant so that the sum of probabilities is $1$. Find constant $\mu$ such that $S_n/n\to \mu$ in probability where $S_n=\sum_{k=1}^nX_k$.   Here $E(X_n)=\infty$. I'm a bit lost after this. In general how does one find constants like this? Smallest possible triangle to contain a square I was looking at * and started thinking about the case of a polygon with 4 sides: a square.   The question asks for a program that can take a polygon of N sides and return the smallest possible polygon of N-1 sides that contains the original polygon.  Thinking about it, I wasn't sure what the optimal triangle encapsulating a square would look like. In KSab's answers, he returns a triangle that looks like this:    This area is 2*(area of the square). With some easy guess-and-check work I found that this seems to be optimized. How do you prove that there is no better solution?  EDIT: another consideration for the orientation of the triangle could be this: Why am I getting a NoClassDefFoundError in Java? I am getting a NoClassDefFoundError when I run my Java application.  What is typically the cause of this? Consider a block cipher with a key of size 128 bits but a small block size, say 32 bits.  Is this kind of block cipher secure?  I would like to know to what extent I can use a small block cipher, like a 32 bit block cipher. What are the constraints so that the use is acceptable in a real life application.  For instance, if we use a one-time key, that is, to encrypt only one message. Besides, the message could be small.  Suppose that when we want so send one file, we perform a key agreement so that we use the key for one message. This scenario is not efficient, but the CPA find-then-guess game is not adequate in this case. Entire function bounded by a polynomial is a polynomial Suppose that an entire function $f(z)$ satisfies $\left|f(z)\right|\leq k\left|z\right|^n$ for sufficiently large $\left|z\right|$, where $n\in\mathbb{Z^+}$ and $k&gt;0$ is constant. Show that $f$ is a polynomial of degree at most $n$. How to disable the Windows8 volume On-Screen-Display? Here is a picture of what i am talking about.    I am at my wits end with that annoying thing, please somebody help me. Is there a measurable set $A$ such that $m(A \cap B) = \frac12 m(B)$ for every open set $B$? Let $V$ be a finite dimensional vectorspace over a field $\mathbb{ F}$. It's easy to show that if $U$ and $V$ are subspaces of $V$ then $U \cap V$ is a subspace. But what if there are an infinite number of them? I have seen sometimes in pure maths that you take an arbitrary finite collection of sets and show the statement you are trying to prove is true for them to deduce it is true for the whole infinite collection. Why is this technique allowed? Can I do it for this case? Why?