Mathematical induction with an inequality and factorial notation: $n! > n^2$
Prove by induction that $n^2<n!$
Detecting superfluous #includes in C/C++? How do I install the latest version of EMACS and pick the appropriate UI? I'm running the latest Kubuntu (12.04 beta 2) and I would like to run the latest emacs (currently v24). The repos are one version behind. What's the best way to install v24 or later (and avoid future version conflicts)?  Also, is there any reason not to aways use the GUI version of emacs if X is running? For example, could I set the GUI emacs version as the default text editor and use it to edit cron jobs (crontab -e)? I'm assuming the answer is yes, but since I haven't done that yet (my default editor is nano), I want to check if there are reasons I should leave nano as the default editor.  Usually when I'm working on the command line I end up using nano. Now that I think about it, I have no idea why I keep doing that. Is there any downside to calling a GUI editor when working in an X terminal?  EDIT: I briefly tested these two versions   GNU Emacs 24.0.94.1 (x86_64-pc-linux-gnu, GTK+ Version 3.3.20) from  GNU Emacs 23.3.1 (x86_64-pc-linux-gnu) installed by default in Kubuntu.   .  Unfortunately (for me) the defaults installed version (23.3.1, 23.3+1-1ubuntu9) is the nox version.   Package: emacs23-nox Status: install ok installed Version: 23.3+1-1ubuntu9 Replaces: emacs23, emacs23-gtk, emacs23-lucid   The package with version 24 opens in GUI mode by default. That's what I prefer. Some of the version 24 changes that interest me are listed in the references below.   But there appear to be a multitude of different packages and versions I could install.  References:   What’s New In Emacs 24 (part 1) | Mastering Emacs  "    shell-mode uses pcomplete rules, with the standard completion UI.  Yowzah! There’s a lot of cool, new functionality hidden away in this gem of a change." EmacsWiki: Recent Changes Detach (move) subdirectory into separate Git repository Post a Form to Popup window not to the parent keyboard hard remap keys? Stack Overflow as a reference in a professional paper/presentation Suppose I'm doing an academic paper, journal article, or other professional presentation.  Would you say that it would be possible to use Stack Overflow as a reference?    Of course I'm pretty sure that the answer here would be "yes."   So here's the follow up: When, if ever, would it be a good idea to cite a Stack Overflow question as a reference in an professional paper/presentation of some kind? Interpreting the end of Inception Sorry for the vague title--I don't want the title to be a spoiler.  I've seen the movie three times, and the last two times I looked specifically for clues to this question, but found none.  The final scene in  shows       Cobb's top spinning, as he goes off to be reunited with his children.  The top continues to spin, then the movie ends, without telling us if the top topples--and therefore revealing whether he's in the "real world" or still in a dream. Do we know if he was in a dream at the end of the movie?   I'm assuming the answer is that we simply cannot know.  But did I miss anything?  Were there clues that I missed? Is there a good Valgrind substitute for Windows? Reference template variable within Jinja expression Minecraft Inventory Saving I am making an RPG map, and was wondering how to "save" the game.  If you die, you would revert back to a save that happens automatically or manually, and I was wondering how to have it so that you will have all the items you had then, and none of the items you got after you saved (so /gamerule keepInventory won't work).  The only way I can think of doing this is having this long, long, annoying set of command blocks to test for all the items in the game, and then have another 64 command blocks for each of those items, testing for the amount of the item. I've just upgraded from Ubuntu 18.04 to its newest LTS version - 20.04. While it comes with some interesting changes, the Desktop icon system was messed up in my opinion. When you hover the mouse cursor over the icons, you see a huge space marked around them that cannot be violated (as you can see in the image below) so that they need to be placed very far apart from each other.  18.04 allowed you to place icons much closer to each other and didn't have that marked space around them. This new way leaves much less space on the Desktop to organize large amounts of icons - including folders, files and shortcuts. Is there a way I can significantly reduce the size of icons and their "spaces" or go back to the old system of organizing files? On "Settings", there is a tool to change the size of Dock icons, but not of Desktop icons.  Also, every time I move or delete something, the Desktop "flashes" and the icons seem to rearrange themselves automatically, nothing of which happened in 18.04. I also can't move anything directly to the Desktop; I need to move to the Desktop folder on Nautilus. This makes me start to think about downgrading Ubuntu back to 18.04. How does Azkaban's management work? 3 Statements of axiom of choice are equivalent This winter I started to study much harder the set theory and especially the axiom of choice. Unfortunately, I have problems with solving the next exercise:  Prove that the 3 statements of the axiom of choice are equivalent :  1) For any non-empty collection $X$ of pairwise disjoint non-empty sets, there exists a choice set.  2) For any non-empty collection $X$ there is a choice function.  3) For any non-empty set $X$, there exists a function $f:P(X)\setminus\{\varnothing\}\to X$ so that for any non-empty set $A\subseteq X$, $f(A) \in A$. What is the cause of this sudden drop in CV queue size? Separator between command list and } K-means is a widely used method in cluster analysis. In my understanding, this method does NOT require ANY assumptions, i.e., give me a dataset and a pre-specified number of clusters, k, and I just apply this algorithm which minimizes the sum of squared errors (SSE), the within cluster squared error.  So k-means is essentially an optimization problem.  I read some material about the drawbacks of k-means.  Most of them say that:   k-means assumes the variance of the distribution of each attribute (variable) is spherical;  all variables have the same variance; the prior probability for all k clusters is the same, i.e., each cluster has roughly equal number of observations;   If any one of these 3 assumptions are violated, then k-means will fail.  I could not understand the logic behind this statement. I think the k-means method makes essentially no assumptions, it just minimizes the SSE, so I cannot see the link between minimizing the SSE and those 3 "assumptions". Why was C-3PO's memory wiped, but not R2-D2's? In Revenge of the Sith after Luke and Leia are born, they are sent to separate parts of the galaxy. The droids are given to Captain Antilles, with the instructions to clean them up, and have C-3PO's memory wiped. Why just C-3PO's and not also R2-D2's?   Initially I thought it was due to R2-D2's inability to communicate verbally, but he not only can communicate via text message (as seen in The Empire Strikes Back I believe), but we see other characters understanding his blips and bleeps as well. Arranging GUI elements in QGIS 3 processing model user interface Using QGIS 3 graphical modeler I created a model with a variety of input parameters (> 10). When starting the model, a nice user interface is generated. But the arrangement of the GUI elements is totally confused and apparently unpredictable during creating the model. It does neither seem to depend on the arrangement of input parameters in the graphical modeler nor on the chronological order in which the input parameters are added to the model.   Is there a way that let's me arrange the GUI elements in the order I desire? Is there a way to show that $\sqrt{p_{n}} &lt; n$?  In , I show that $f_{2}(x)=\frac{x}{ln(x)} - \sqrt{x}$ is ascending, for $\forall x\geq e^{2}$. As a result, $\forall n \geq 3$ $$\frac{p_{n}}{ln(p_{n})} - \sqrt{p_{n}}\leq \frac{p_{n+1}}{ln(p_{n+1})} - \sqrt{p_{n+1}}$$ Also (and as a result), $\forall n \geq 3$ $$ \frac{p_{n}}{ln(p_{n})} - \sqrt{p_{n}} &gt; 0$$ Or $$ \frac{\pi (p_{n})}{p_{n}/ln(p_{n})} &lt; \frac{\pi (p_{n})}{\sqrt{p_{n}}}$$  According to  $$\displaystyle\smash{\lim_{n \to \infty }}\frac{\pi (p_{n})}{p_{n}/ln(p_{n})}=1$$ Or, $\forall \varepsilon &gt;0$, $\exists N(\varepsilon )$: $\forall n&gt;N(\varepsilon )$ $$1- \varepsilon &lt; \frac{\pi (p_{n})}{p_{n}/ln(p_{n})} &lt; 1+ \varepsilon$$ Or $$1- \varepsilon &lt; \frac{\pi (p_{n})}{p_{n}/ln(p_{n})} &lt; \frac{\pi (p_{n})}{\sqrt{p_{n}}}$$ As a result $\forall \varepsilon &gt;0$, $\exists N(\varepsilon )$: $\forall n&gt;N(\varepsilon )$ $$(1 - \varepsilon ) \cdot  \sqrt{p_{n}} &lt; \pi (p_{n}) = n$$  But this is not enough.  Interestingly,  is true iff function $f_{4}(x)=\pi (x) - \sqrt{x}$ is strictly ascending ($x &lt; y \Rightarrow f(x) &lt; f(y)$) for prime arguments.  If $f_{4}(p_{n}) &lt; f_{4}(p_{n+1})$ then $$\pi (p_{n}) - \sqrt{p_{n}} &lt; \pi (p_{n+1}) - \sqrt{p_{n+1}}$$ Or $$\sqrt{p_{n+1}} - \sqrt{p_{n}} &lt; \pi (p_{n+1}) - \pi (p_{n}) =1$$  And vice-versa, if $$\sqrt{p_{n+1}} - \sqrt{p_{n}} &lt; 1$$ Then $$-\sqrt{p_{n}} &lt; -\sqrt{p_{n+1}} + 1$$ Or $$\pi (p_{n})-\sqrt{p_{n}} &lt; \pi (p_{n}) + 1 -\sqrt{p_{n+1}} = \pi (p_{n+1}) -\sqrt{p_{n+1}}$$  So, if Andrica's conjecture is true then $\forall n \geq 3$ $$\pi (p_{n})-\sqrt{p_{n}} &gt; 0$$ Or $$\sqrt{p_{n}} &lt; \pi (p_{n})= n$$ How to calculate a confidence interval for estimating a proportion when the population is very small? I plan to execute a little study on whether dentists tend to grant privately insured patients (PRIV) a sooner appointment compared with publicly insured patients (PUB). I want to restrict this study to the dentists of a single town in Germany.  In this town there are about 500 dental practices and I am willing to call maximum 100 practices (twice, once as a PUB and once as PRIV). (A sample without replacement of size up to 100)  So the result of this examination would be a list of up to 100 practices with an associated value of 1 - if the appointment for the PRIV was more than two days sooner - and a 0 - if not. The proportion of 1s is what I want to estimate.  Now the sources I have been reading always assumed a much larger population with a finite population correction close to 1. This is why I doubt that blindly using a conservative or approximate confidence interval would lead to a statistically meaningful result.   So my first question is, of course, whether it is reasonable at all trying to estimate the proportion using a confidence interval in this case? And if yes, then what statistical technology/method (leading to a CI) would be a good choice for this use case?   One idea that comes to mind is using a sample size of 25 f.x., in that case the FPC would be 0.95 - "close enough" to 1. But it seems stupid trying to improve the quality of an estimation by reducing the information used for the estimation.