I have to do a presentation with beamer. In a frame I want to insert an image as a object in itemize, so in the first step is only visible the writings, while in the second step the image appears. Here is my code:  \documentclass{beamer} \usepackage[italian,english]{babel} \usepackage[latin1]{inputenc} \usepackage[T1]{fontenc} \usepackage{amsmath} \usepackage{ragged2e} \usepackage{media9}  \begin{document}  \begin{frame} \frametitle{Key Variables in the \textit{Bubble} Phenomena} \begin{itemize} \setbeamercovered{transparent} \item[]<1-> The mean value $\bar{\beta}_{i,t}$ of the intensity parameter is crucial for the development of the synchronization phase, hence it also affects the production volume: %\vspace{0.1cm} \begin{center} \item[]<2-> {\includegraphics[width=.45\textwidth]{gdp_betaC}} \end{center} \end{itemize} \vspace{2cm} \end{frame}   I don't know why, but if I use itemize with different writings as steps the code works, but if I include the image in the second step, the latter appears together with the first one.

Recently, I asked  question, about how to let bullets appear in a frame in a Latex Beamer document.  How would I do this with pictures? Say that I want a slide which contains one graph in the upper half and after clicking another graph appears in the lower half. The answer to my previous question does not help in this case, because there is no itemize/enumerate environment. Any help is appreciated!


I return a List from my A class. I would like to remove the first element from the list and add it as the last element to the same list. I did it this way.  myList.add(myList.get(0)); myList.remove(0);   The target hardware is Android OS. Should I code my A class in a way that it returns an ArrayList, or a LinkedList? Which would be better for the following scenarios:   myList has always 100 elements myList has always 10 elements   Maybe I see a problem where there is none. Do you think I shouldn't care for performance in this case, since the problem size is (for both 1 and 2) is small?  I am aware of the saying "premature optimisation is the root of all evil". That's why I am hesitating before changing my implemantation (as for now, my A object returns an ArrayList).

I've always been one to simply use:  List<String> names = new ArrayList<>();   I use the interface as the type name for portability, so that when I ask questions such as these I can rework my code.    When should  be used over  and vice-versa?


Can someone please help my identify this icon in notification bar. What app is it from?? Thank you

I'm concerned about an app on my child's phone. I saw an app icon in the notification area that looked strange (Andy Android head, slightly tilted as its icon).  How can I find out what app it is from just having seen that icon in the notification bar?


Do we use abstract algebra in real life?   Is there any application of abstract algebra in real life?

I would like to know whether there are examples where finite group theory can be directly applied to solve real world problems outside of mathematics.  (Sufficiently applied mathematics such as cryptography, coding theory, or statistics still count.)  Let me clarify: I am not interested in applications of elementary group theory which happen to involve finite groups (e.g. cyclic/dihedral/easy groups as molecular symmetries).  I am interested in applications of topics specifically coming from finite group theory as a discipline, like one might see in , , or .  "The Schur multiplier has order 2640, so we should point the laser that way."   "Is this computer system secure?"  "No - Frobenius kernels are nilpotent."  I'm aware of , but many of the applications listed there are inside mathematics or fall in the "applications of easy groups" category.  It is entirely possible that what I'm looking for doesn't exist, and that finite group theory is still an untouchable, pure subject, like number theory in the days of G. H. Hardy.  But perhaps not.  Does anyone know of any applications of the higher level stuff?


I have read that even if we can control our food and lifestyle and keep things as ideal as possible, there are other factors beyond our control like effects from neutrinos passing through our body that would accumulate over time, and may cause harm. More over, Earth's natural radiation, and the Cosmic background radiation may as well play a part.  I wonder what if we somehow removed these as well, will one be able to live forever?! I have heard people say that this is an impossibility, but I wonder why?!  Thanks.

Following from this question: :  Is there any evidence that human bodies have systemic self-destruction built into their developmental program? I'm not talking about the cell death response, which I know is an important part of growth, development and cancer prevention.  I've read some things about telomere-shortening but don't know if this is a cause or an effect.


I have sample data for 'Times between successive crashes of a computer system' which is for a 6 month period and the data is given in hours. The data in brief is : 1,10,20,30,40,52..... I need to use the Kolmogrov-Smirnov test to examine the goodness of fit for a exponential distribution. I am given parameter α = 0.00435 , Mean = 1/α = 230 hours. The total number of data points in the sample is 22. I'm not sure how to calculate the sample cumulative distribution function (Fs(x)). Currently my approach to it was that each data point should be divided by the sample size(22). As in for data points 1,10,20 the  Fs(x) = 1/22,10/22 etc. Can I get a confirmation on this approach ?

I am reading the , by Larry Wasserman. At page 12, he defines the empirical distribution function as:  The empirical distribution function $\hat{F_n}$ is the CDF that puts mass $\frac{1}{n}$ at each data point $X_i$. Formally,  $$\hat{F_n}(x)=\frac{1}{n}\sum^{n}_{i=1}I(X_i\le x)$$  where   $$I(X_i\le x)=\left\{\begin{matrix}  1& if\ X_i \le x\\  0 & if \ X_i>x \end{matrix}\right.$$  My questions are:   Why is $\frac{1}{n}$ called mass? The CDF puts mass $\frac{1}{n}$ to each data point $X_i$, then, by my understanding, it should be $\frac{1}{n}X_1+\frac{1}{n}X_2+...+\frac{1}{n}X_n$.    Why is it $\hat{F_n}(x)=\frac{1}{n}\sum^{n}_{i=1}I(X_i\le x)$? I think this formula puts mass $\frac{1}{n}$ on each indicator function $I(X_i \le x)$ but not $X_i$.  What is the meaning of "puts" something "at each data point"?


Can I take a picture with a  Canon EOS1300D with a Canon EF 50 mm f1.8 STM Lens of the milky way?  Thank you.

Can the milky way actually be photographed ? I know the image is manipulated, and is probably a composite, but how do you capture such contrast in the milky way? Is an equitorially mounted scope required? Any advice or pointers are welcome, thanks.  I'm heading out towards much less light polluted areas middle of next week and I want to try some nighttime sky captures with my 7D.  Additional info: I just found  on wikipedia that says: 54s, tripod mounted 5D, 16mm lens, f/2.8, ISO800. What else do I need to be aware of? My 7D is only an APS-C and the widest lens I have is 19mm. I'm thinking that might not be wide enough to capture an interesting shot?


I want to install the secondary font in ubuntu, I have downloaded it locally. How I can install it?

Question says it all. I need them to be available in gimp.


I create a recent files smart folder, place it in the dock. I right click and choose display as folder. I get the following icon:    Is there a way to change this icon?

I want to move the folder recent item to dock because it helps me a lot. But this is not the only one folder i use in dock, there is another one such as download folder. Because of the icon shown on these folders based on the first item in each folder, sometime it confuses me.   The question is, can I change the icon of those folders in dock so that I can differentiate them easily?


This question was essentially asked 3+yrs prior, but I don't see any recent updates.   I'd like to set my iphone to engage airplane mode for an hour (example) and then turn off airplane mode/engage cellular service an hour later.  Is that possible?

I want to schedule Airplane Mode during the night (10PM–6AM) on my iPhone.  How can I do that?  I used to turn off my previous phone (a non-smartphone). I do that especially to save some battery life.


Reading package lists... Error! E: flAbsPath on /var/lib/dpkg/status failed - realpath (2: No such file or directory) E: Could not open file  - open (2: No such file or directory) E: Problem opening  E: The package lists or status file could not be parsed or opened.   I use Ubuntu 19.10

When I run sudo apt update in Ubuntu 18.10 I get this error message:  E: flAbsPath on /var/lib/dpkg/status failed - realpath (2: No such file or directory) E: Could not open file  - open (2: No such file or directory) E: Problem opening  E: The package lists or status file could not be parsed or opened.   After running sudo cp /var/lib/dpkg/status-old /var/lib/dpkg/status it's showing this error message:   cp: cannot stat '/var/lib/dpkg/status-old': No such file or directory


I have table named users in which users first name & last name are gets inserted. User name may contains special character also like "Cé".  So, when I go for search user from user table with special character as mentioned above(e.g. Cé) it returns the value in mysql but does not display in PHP array.  Search with normal keywords work properly in mysql as well as in PHP. But the issue raised for special character search. It search from query but it does not return in PHP variable.  I have written the below query.  SELECT first_name,last_name users WHERE concat(first_name,' ',last_name) LIKE '%Cé%' status='active';   It returns the result in MYSQL but not in PHP.

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


Find the principle part of the Laurent expansion of the function $f(z) = \frac{1}{(e^z - 1)^2}$ about $z = 0$. Hint: First show that $f$ has a pole of order $2$ at $z = 0$.  I already found the pole of order $2$ using Laurent expansion. But I am not able to proceed further with finding the principle part.   Thank you

Trying to find the principal part of the Laurent Expansion of $(\exp(z)-1)^{-2}$ about $z = 0$.  I know that because there is a pole of order two at $z=0$ I need to only find the constants for $n=-1,-2$.


Basically my question is about the following:  using myName = System.Web;   I recently came across some code which did something very similar to that above. My question boils down to the following points:   What is doing this even called? Why would you need to this? Pros/Cons of doing this?   I understand one of the benefits in which I have used this type of declaration:  using Security = System.Web.Security;  ...  _roles = (SimpleRoleProvider)Security.Roles.Provider; _membership = (SimpleMembershipProvider)Security.Membership.Provider;   As I had an entity named Membership I couldn't just do Membership.Provider without a conflict. So here the using declaration allows me to shortern the full use of System.Web.Security.Membership to just Security.Membership.Provider which feels nicer from an OCD point of view.

Where or when would one would use namespace aliasing like  using someOtherName =  System.Timers.Timer;  It seems to me that it would just add more confusion to understanding the language.


I'm very new to coding and currently trying to learn C#. As a mini project/ practice I'm trying to create a mini address book, as part of that I want to calculate age from birthDate and today. My code to gather this date is as so:  DateTime today = DateTime.Today; public int age(DateTime today, DateTime birthDate) {        if (today.Month < this.birthDate.Month)     {         return ((today.Year - this.birthDate.Year) - 1);     }     else if (today.Month == this.birthDate.Month )     {         if (today.Day >= this.birthDate.Day)             return (today.Year - this.birthDate.Year);         else             return ((today.Year - this.birthDate.Year) - 1);     }      else         return (today.Year - this.birthDate.Year); }   However when I try to call a Console.WriteLine(person.age) or do anything with any of my person.age it tells me     The best overload method match for 'System.Console.WriteLine(string, params object[])' has some invalid arguments.   However as much as i've tried I can't work out what I have done wrong.

Given a DateTime representing a person's birthday, how do I calculate their age in years?


Gauge Higgs unification .  Does gauge higgs unification has been proved ？ If so , what is it exactly meaning ?

(2010) hypothesizes that Higgs bosons might be absolutely stable, allowing them to serve as a cold dark matter candidate:     The Higgs boson is in the backbone of the standard model of electroweak interactions. It must exist in some form for achieving unification of interactions. In the gauge-Higgs unification scenario the Higgs boson becomes a part of the extra-dimensional component of gauge fields. The Higgs boson becomes absolutely stable in a class of the gauge-Higgs unification models, serving as a promising candidate for cold dark matter in the universe. The observed relic abundance of cold dark matter is obtained with the Higgs mass around 70 GeV. The Higgs-nucleon scattering cross section is found to be close to the recent CDMS II and XENON10 bounds in the direct detection of dark matter. In collider experiments stable Higgs bosons are produced in a pair, appearing as missing energies and momenta so that the way of detecting Higgs bosons must be altered.      –, Yutaka Hosotani (2010-03-31)   Has the hypothesis in the above article been proved? What about WIMPs?


If $a, b, c$ are positive real numbers such that $a+b+c=3$, prove that $\sqrt{a} +\sqrt{b} +\sqrt{c} \ge ab+bc+ac$  My try: First I tried dividing both sides by $\sqrt{abc}$. Then I squared both sides. Afterwards...... no afterwards. I haven't managed to do much from here.

Let $a,b,c$ are non-negative numbers, such that $a+b+c = 3$.  Prove that $\sqrt{a} + \sqrt{b} + \sqrt{c} \ge ab + bc + ca$    Here's my idea:  $\sqrt{a} + \sqrt{b} + \sqrt{c} \ge ab + bc + ca$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) \ge 2(ab + bc + ca)$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) - 2(ab + bc + ca) \ge 0$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) - ((a+b+c)^2 - (a^2 + b^2 + c^2) \ge 0$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) - (a+b+c)^2 \ge 0$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge (a+b+c)^2$  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge 3^2 = 9$  And I'm stuck here.  I need to prove that:   $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge (a+b+c)^2$ or  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge 3(a+b+c)$, because $a+b+c = 3$  In the first case using Cauchy-Schwarz Inequality I prove that:  $(a^2 + b^2 + c^2)(1+1+1) \ge (a+b+c)^2$  $3(a^2 + b^2 + c^2) \ge (a+b+c)^2$  Now I need to prove that:   $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge 3(a^2 + b^2 + c^2)$   $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) \ge 2(a^2 + b^2 + c^2)$   $\sqrt{a} + \sqrt{b} + \sqrt{c} \ge a^2 + b^2 + c^2$   I need I don't know how to continue.  In the second case I tried proving:  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) \ge 2(a+b+c)$ and  $a^2 + b^2 + c^2 \ge a+b+c$  Using Cauchy-Schwarz Inequality I proved:  $(a^2 + b^2 + c^2)(1+1+1) \ge (a+b+c)^2$  $(a^2 + b^2 + c^2)(a+b+c) \ge (a+b+c)^2$  $a^2 + b^2 + c^2 \ge a+b+c$  But I can't find a way to prove that $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) \ge 2(a+b+c)$  So please help me with this problem.  P.S   My initial idea, which is proving:  $2(\sqrt{a} + \sqrt{b} + \sqrt{c}) + (a^2 + b^2 + c^2) \ge 3^2 = 9$  maybe isn't the right way to prove this inequality.


This problem has kept many Ubuntu users like me from using x2go and we are forced to choose vnc or other alternatives.    sudo add-apt-repository ppa:x2go/stable cannot add ppa: ppa:x2go/stable please check that the ppa name or format is correct

I am trying to turn a fresh install of Ubuntu 14.04 into an X2go server. I have followed the instructions here:   I have taken these steps:   su Add the line below to /etc/apt/sources.list  deb http://us.archive.ubuntu.com/ubuntu trusty main universe  add-apt-repository ppa:x2go/stable   I get this message:  cannot add ppa: ppa:x2go/stable please check that the ppa name or format is correct


Let $U,V$ subgroup of G with $|G:U|,|G:V|<\infty$. Also  $\gcd(|G:U|,|G:V|)=1$. Show that $G=UV$.  Please help to proceed with this question , first step where I get stuck is whether I can conclude G finite or not also I think I have to show $\gcd(|U|,|V|)=1$ which implies $U\cap V =\varnothing$ thus $G=UV$ . But I don't know how to proceed .

I think I remember seeing a theorem about this in my Abstract Algebra class, but I cannot seem to find the reference for it anymore.   Let $G$ be a group and let $H$ and $K$ be non trivial subgroups of $G$. Are there any sufficient conditions on $H, K$ and $G$ such that $G = HK$? (In other words $\forall g \in G$, there exist $h \in H$ and $k \in K$ such that $g = hk$)


I m confused in the direction of current flow as I studied that current flow from + to -  But current flow from negative to positive also called electron flow... & Also current which flow from positive to negative called conventional current... As I know that electron current is a flow of electron towards the positive.... But what is the flow of conventional current at the same time ??? Are protons are flowing ???? Plzzz explain what actually happens about current (- to +) or  (+ to -)

I am starting to see a lot of people claiming that convential current is 'wrong' because Franklin made an error when he first started investigating electrostatics, and that later scientists didn't bother correcting the mistake, but preferred to keep the 'convention' (here is a classic example: )  I always thought he didn't get it wrong. He said that current is positive in the direction that positive charge flows, and vice-versa. He of course had no way to know which side of two sticks behind rubbed actually gained or lost mass. So he wasn't wrong. What were you taught?  P.S. I can't help but feel we are lucky that he got it 'backwards', because clearly many people are confused about electrostastics (including the author of that text book!) and believe electricity has to involve electrons (an unfortunate name... why couldn't they have been named negatrons...)


Running sudo <command> failed with:  sudo: unable to change to root gid

When I login as guest I am unable to execute any command with sudo.  E.g.:  sudo ps   returns:  sudo: unable to change to sudoers gid: Operation not permitted   How can I fix this?


I have one disk with all ubuntu partitions and a separate Data partition.  If i try to open a file located on Data partition through a program the file is unavailable. If i open the partition in Files and then try to open the the same file through the same program everything works.  Is there something wrong with the mounting options and how do i best check that?

Sometimes when I restart my computer, my drives will mount but sometimes they won't (like right now when I'm typing this question out).   Is there an easy way, like a program that can mount them for me? Going in the console, making folders, etc, is NOT what I want. I like how Windows does it where they always mount the drives no matter what.   If there isn't a program how else can I easily mount all drives?


What is the closed summation form for $1 + 3 + 5 + \cdots + (2n-1)$ ?  I know that the closed form for $1 + 2 + 3+\cdots  + n = n(n+1)/2$ and I tried plugging in $(2n-1)$ for $n$ in that expression, but it didn't produce a correct result:  $(2n-1)((2n-1)+1)/2$  plug in 3   $(2n-1)((2n-1)+1)/2 = 6 != 1 + 2 + 3 = 9$

How to derive this formula?   $$n^2=\sum_{k=1}^n(2k-1).$$


Evaluate $\large \int_0^1\left(\frac{1}{\ln x} + \frac{1}{1-x}\right)^2 \mathrm dx $ $$$$ I was given this integral by a friend who saw this here on MSE. He asked me if I could solve it using the very basic tools I have. I was of course unsuccessful.$$$$  My short and unsuccessful attempt: $$\large \int_0^1\left(\frac{1}{\ln x} + \frac{1}{1-x}\right)^2 \mathrm dx $$  $$\int_0^1\left(\frac{1}{(\ln x)^2} + \frac{1}{(1-x)^2} +\frac{2}{\ln x(1-x)}\right) \mathrm dx $$ $$\int_0^1\frac{1}{(\ln x)^2}+\int_0^1\frac{1}{(1-x)^2}+\int_0^1\frac{2}{\ln x(1-x)}$$  The problem (apart from the fact that I don't know as yet how to attempt the third integral) is that the second integral (I think) diverges.  Could somebody please help me solve it using preferably only these: Integration by Parts, Integration by Substitution, Partial Fraction Decomposition or Differentiating under the Integral Sign?$$$$ Thanks so much in advance, and I'm truly sorry for the trouble I have caused.

Evaluate $$\int_0^1\left(\frac{1}{\ln x} + \frac{1}{1-x}\right)^2 \mathrm dx$$


Prove that if $(k_{1},k_{2},...,k_{n})$ and $(z_{1},z_{2},...,z_{n})$ are both complete system of residues $\bmod n$ then $$(k_{1}+k_{2}+...+k_{n}) \equiv (z_{1}+z_{2}+...+z_{n})\mod n$$  and $$(k_{1}k_{2}...k_{n}) \equiv (z_{1}z_{2}...z_{n})\mod n$$ can you give me some hints to complete this proof? I know that proofs are not obvious but in this case $(k_{1},k_{2},...,k_{n})\mod n$  and   $(z_{1},z_{2},...,z_{n}) \mod n$ I probably need to apply some theorems in number theory for complete system of residues.

I have seen other criteria for divisibility by 7. Criterion described below present in the book Handbook of Mathematics for IN Bronshtein (p. 323) is interesting, but could not prove it. Let $n = (a_ka_{k-1}\ldots a_2a_1a_0)_{10} = \displaystyle{\sum_{j=0}^{k}}a_{k-j}10^{k-j}$. The expression $$ Q_{3}^{\prime}(n) = (a_2a_1a_0)_{10} - (a_5a_4a_3)_{10} + (a_8a_7a_6)_{10} -\ldots  $$ are called alternating sum of the digits of third order of $n$. For example,  $$ Q_{3}^{\prime}(123456789) = 789-456+123=456 $$ Proposition: $7 | n \ \Leftrightarrow \ 7 | Q_{3}^{\prime}(n)$.  proof. ??  Thanks for any help.


Ubuntu 11.04 was working fine with my Nvidia GT550M graphic card. It has got all shadows, effects etc. But yesterday i noticed the "additional drivers" icon in notification area and installed it. But now after login it says "your graphic card does not support unity, log in to classic gnome". how can i uninstall the driver and roll back to default one?

I've installed nVidia driver successfully but I want to go back to Nouveau driver and eliminate any xorg.conf file created by nVidia config tools.  What is the proper way to do it? (not ending up with no driver at all, or no X server)


I am looking for an audio enhancer which would act for all the sound playing in Ubuntu 12.04 LTS (audio/video players, browser) ..something like DFX for Windows!  Thanks for your reply.

What I am looking for is to have system wide implementation of sound enhancements like bass boosts, echoes, Fidelity, Stereo enhancement and so on.  Audio Video players have their own equalizer but they enhance only the audio / video files they are playing.  So to enhance sounds playing such as: YouTube, Spotify, System Sound, etc. I need a enhancer software. Back in Windows, I used to use SRS HD audio lab to do the same.  P.S. I have a horrible Speaker set.


Has anyone used two titan cards in Scalable Link Interface to speed up renders? I'm just curious because I've tried everything.

I have an NVIDIA Titan GPU and I'm able to add another card, but I wonder whether  Blender will benefit from more than one GPUs?  Should I do it as SLI or should I just do it as an added card? I just need some help in understanding how Blender will use either SLI or a second GPU.  Note that I only use Cycles.


It is easy to prove that $\omega_1$ does not have an order-preserving injection into $(\mathbb R, <)$: to each $\alpha \in \omega_1$ we could assign the interval between the image of $\alpha$ and $\alpha + 1$, and this gives uncountably many disjoint open intervals in $\mathbb R$, contradicting its separability.  Intuitively it seems to be that if $\alpha < \omega_1$, there should be an order-preserving injection into $\mathbb R$, but I am having trouble constructing it. If we have $\alpha \to \mathbb R$, we can compose it with a homeomorphism $\mathbb R \to (0, 1)$, and find $\alpha + 1 \to \mathbb R$ by sending $\alpha$ to $(0, 1)$ and $\{\alpha\}$ to 2. However, the limit step is more difficult: if $\lambda < \omega_1$ is a limit, then it is a limit of countably many well-orderings which inject in an order-preserving manner into $\mathbb R$, but you cannot expect these to be "compatible" in a way obvious to me.  Is there a way to make this (or another argument) work? Or are there countable ordinals with no order-preserving injections into $\mathbb R$?

Yesterday, Asaf Karagila's  sparked an extensive discussion on ways of proving that all countable ordinals are embeddable in $\Bbb Q$, and whether particular solutions to this use the Axiom of Choice.  Since the arguments used to prove this can be shady on their use of Choice when formulated tersely, fully fleshed out answers are appreciated.  To be concrete, this question asks for proofs of the following fact:     All countable ordinals $\alpha < \omega_1$ are order-embeddable in the rationals $\Bbb Q$.   Especially answers avoiding the Axiom of Choice are appreciated.    Of relevance and related interest is  (but it's not a duplicate, since that question asks for explicit embeddings).


I very distinctly recall reading a scifi story as a child, possibly a series of stories. Humans land in a solar system and meet a race of aliens that, if I recall correctly, evolve very quickly, and have a cast based racial split; there are technicians, warriors and so on. The race for some reason overpopulates their own solar system and keeps killing itself mostly off, resetting the cycle. They cannot leave their solar system (they have no FTL technology, but the humans do) and are very interested in learning how to. Some story points I remember, all of them being developments/revelations, so obviously spoilers:   The humans arrive in two big ships, and they lose one of the ships due to one of the servant races breeding uncontrollably in the vents. The aliens are surprised that the humans don't periodically vent their air to prevent things like that.    The aliens have sent (one or multiple) solar sail 'powered' ships with members of their race in cryosleep to other planets, but none have reached them yet.  Near finale spoilers I remember:   The humans intercept one of the ancient solar ships and discover that the aliens didn't send scientists but warriors    The humans flee and blockade the solar system because they realize the race is only interested in escaping their solar system in order to breed forever and flood the galaxy. They can do that because even though the aliens have further advanced tech, because the exit jump point from the aliens solar system (or something like that) is inside a gas giant/solar corona/whatever that makes any ships that emerge from their system have their shields down and be easy prey to the humans.  The story ends with:   The humans took some of the aliens (just one ?) with them, and the alien either monologues to itself or to another one that humans will forever keep them trapped, but that humanity as a race will some day through calamity, war, politics or whatever stop bothering, and their race will eventually escape.  It bothered me for years that I couldn't remember the name of the story because I would love to read it again.

I read this book when I was a teenager, or in my early twenties, so that puts it no later than 1979. My favorite authors at the time were (of course) Asimov, Bradbury, Clarke, Heinlein, and a few others. I've looked up the bibliographies of most of these, to no avail.  The story in general: Earth people spot a small alien craft near the sun.  Investigating, they find a lone passenger, a female pilot from an alien race, whose distinguishing characteristic is that her hands are claws of two different sizes: one large, one small.  She is suspiciously quiet about how she got there (I think).  Examining the video footage, they find that, as the Earth ship approached, she jettisoned four other passengers into the sun.  There is much talk about sexual practices (which makes me think Heinlein).  Earth society is going through another "sex is sinful" stage, but the alien female has a biological imperative to breed; if she doesn't have sex, she'll die.  Since her shipmates are gone, she keeps getting sicker.  They return her to her own world, and find that there are five different races, all of which build a fully-integrated society.  The creatures are of different size, shapes and colors, but all have the same mismatched claws.  One breed of alien is like a technician, and, for example, while waiting outside by the car (which are a story in themselves), he or she uses the larger claw as a tool to repair, upgrade, or modify the vehicle.  All of the aliens are capable of things like this, so there are no businesses to take care of it.  Basically, everyone does everything, if I recall correctly.  I don't remember the resolution of the story, and probably for that reason it's been bothering me for several months. If this sounds familiar to anyone, please let me know the title and author, and if I can download a digital copy somewhere.


I'm very new to blender and are using it to edit videos. I slapped 2 osu clips and a end card together but for some reason it only wants to save as a .blend file.

So I made an intro using animation and it saves it as a .blend and I want it so save as a video like .mp4 or something like that. I've tried changing the codec because I tried opening the intro with windows media instead of blend. I didn't try all the codec's but I tried some of them.


I am using a simple regex to try and classify strings as either relating to entitlements (wages) or other.   I have tested the regex in regex101.com and it seems to work as expected but when I run the code I get some strange results  import re  wages_regx = re.compile(r" pay | payment | salary | salaries | wages? | rates? | hourly rates? | allowances? | penalties | penalty | overtime | under payments? | over payments? | entitlements? ", re.I)  def classify(string):     if wages_regx.match(string):         return 'Entitlements'     else:         return 'Other'   Tests  classify('I have an question about my wages rate.')  # Returns: Other (Should return Entitlements) should match on (wages? and rates?)  classify(' wages ')  # Returns Entitlements as expected  classify('ras wages c')  # Returns Other (Should return Entitlements)  classify(' wages c')  # Returns Entitlements as expected

What is the difference between the search() and match() functions in the ?  I've read the  (), but I never seem to remember it.  I keep having to look it up and re-learn it.  I'm hoping that someone will answer it clearly with examples so that (perhaps) it will stick in my head.  Or at least I'll have a better place to return with my question and it will take less time to re-learn it.


I want to put whole of a text on a single page. I don't have constraint on the text font. So if the text was too long, the text font should be small. How can I do this automatically using LaTeX? For example, if I write the \lipsum, the printed document should contain exactly one page.

The question Is there any way to automatically scale and put an entire document on an A0 page? The thesis for which this is to be done is available as LaTeX code, as well as PDF output. Of course I know it is possible to do this manually, but I would prefer a LaTeX solution.  A small background Our university introduced a new page limit for master theses. This is not exactly appreciated by the teaching staff as well as students. To make a little joke, we decided to try to arrange an entire thesis (of approximately 200 pages) on a A0 poster, put it up in the hallway, and put a magnification glass next to it with a note saying: "New page limit introduced: 1 page maximum for all upcoming theses!"  The final result As some of you asked for this: below you can see a picture of the final result. (I "professionally removed" some of the sensitiv information.) We presented the poster during my final presentation and everyone liked it a lot! Now, it is on display next to my office and is still attracting some attention once in a while.


Since none of the solutions found here  worked for me on Mojave, I simply disabled the daemon: sudo mv /System/Library/PrivateFrameworks/StorageManagement.framework/Resources/diskspaced /System/Library/PrivateFrameworks/StorageManagement.framework/Resources/diskspaced.disabled  Brute force, I know, but unloading/removing/disabling using launchctl didn't work and I got annoyed. Is there a more elegant way to turn off Apple's constant nannying alert messages?

After upgrading to macOS Sierra, I'm getting the notification that "Your disk is almost full. Save space by optimizing storage.":    The options appear to be to store my files in iCloud, automatically delete files, or manually delete files:    My problem/irritation is that I have 80GB free of my 440GB volume.  The question: is there a way to silence this notification in a (semi-)permanent fashion, or to change the threshold it uses for the notification?


I have an .img file sizing about 600 MiB. When I wanted to burn this file to a CD (not a DVD), I could not find any program capable of doing so. I tried K3b, Brasero, and AcetoneISO. Nothing was able to burn the .img file.  Then i tried to convert it to an .iso with AcetoneISO, but it said i would lose important tracks (multitrack disc). The outcome was a file of 160 MiB or so, so I figured this was no solution either.  I do not want to write the .img image to a  USB stick, but only burn it to a CD. In the case that such an .img image is from a bootable CD, I cannot simply dump its contents to a folder by copying and then burn that folder to the CD-R after mounting it. Doing that would fail to produce a bootable CD.  Is there any program in Ubuntu's repositories that can do this? Is there another way to convert the file?  This is not a duplicate of  because I am asking how to burn an .img image to CD-R or CD-RW and not an .iso. I am not able to find any CD-R software for burning .img image files to a disc.  The reason this is not a duplicate is that I am asking for a method for  how to burn an .img (not an .iso, nor a .bin/.cue) image to a CD-R in Linux. The linked question does not appear to answer this. I am unable to find any burner in the repos in Xubuntu that does this. AcetoneISO does mount the image, but that is not what I want, since it is a multi-track .img (all tracks in one .img file). I also want to burn it to a CD-R so that it remains bootable. K3b and other burners do not accept any .img file for burning.  Converting it to an .iso with AcetoneISO or any other program makes it lose the additional tracks beyond track 1 and possibly also to lose the bootable aspect.

I have downloaded an ISO file recently.  How do I burn it to a CD or DVD or mount it?


I have a MySQL database containing Countries   id  | de          | en          | fr    ---------------------------------------------   1  | Afghanistan | Afghanistan | Afghanistan  2  | Albanien    | Albania     | Albanie ...   I'd like to get a list of the countries, according to visitor's language.  Here's the method in my class :  public function getList($language){     $countries = array();     $req = ('SELECT id, :language FROM country ORDER BY :language ASC');             $q = $this->_db->prepare($req);     $q->bindValue(':language', $language, \PDO::PARAM_STR);     $q->execute();     while ($data = $q->fetch(\PDO::FETCH_ASSOC)) {         $countries[] = new Country($data);     }     return $countries;     $q->closeCursor(); }   It returns an array, but country names are replaced by the language.  It seems bindValue is adding quotes to my variable, which is fine in the ORDER BY, but creates problems in the fields i want to SELECT.  $countryManager->getList('fr');   returns something like this   Array ( [0] => Entities\Country Object     (         [id:Entities\Country:private] => 1         [de:Entities\Country:private] =>           [en:Entities\Country:private] =>          [fr:Entities\Country:private] => fr     )  [1] => Entities\Country Object     (         [id:Entities\Country:private] => 2         [de:Entities\Country:private] =>          [en:Entities\Country:private] =>          [fr:Entities\Country:private] => fr     )   If you have any idea on where the problem might be, i'd be very glad to know :)  Thank you in advance for your help.

Why can't I pass the table name to a prepared PDO statement?  $stmt = $dbh->prepare('SELECT * FROM :table WHERE 1'); if ($stmt->execute(array(':table' => 'users'))) {     var_dump($stmt->fetchAll()); }   Is there another safe way to insert a table name into a SQL query? With safe, I mean that I don't want to do  $sql = "SELECT * FROM $table WHERE 1"


Is the Big Bang instant considered a beginning of all the coordinates of our universe? If we consider the BB to be the Beginning of of our universe, can we call this the Origin of all of the 3 dimensions of space and the 1 dimension of time? Whether it be a point, Planck volume, tiny loop, hole,... it seems we should be able to define it as an Origin that all points of our universe had in common 13.8 BY ago. Why cant we call this a temporal center, and a center of gravity, that happens to be very far away back in time?

If the big bang was the birth of everything, and the big bang was an event in the sense that it had a location and a time (time 0), wouldn't that mean that our universe has a center?  Where was the big bang? What is there now? Are we moving away from the center still? Are these even valid questions?


I need to either prove this is an integral domain or give a counterexample.  I have yet to find a counterexample, but can't seem to prove it on my own.  Would love any advice/help! Thank you!

I have a doubt on something. I have a theorem that says that if $R$ is a ring, then $R/I$ is a domain iff $I$ is prime. Since $X^2-1$ is note prime, $\mathbb Z[X]/(X^2-1)$ is not a domain. But, $X^2-1=(X-1)(X+1)$, and since $X-1$ and $X+1$ are prime in $\mathbb Z[X]$, there are coprime, and thus, by the chinese remainder $$\mathbb Z[X]/(X^2-1)\cong \mathbb Z[X]/(X-1)\times \mathbb Z[X]/(X+1),$$ since $\mathbb Z[X]/(X-1)\times \mathbb Z[X]/(X+1)$ is a domain, then so is $\mathbb Z[X/(X^2-1)$. What is the mistakes here ?


How do I show that for all $x,y\geq 0$, $\frac{x^2+y^2}{4}\leq e^{x+y-2}$? Tried using the mean value theorem but couldn't figure out how to use it properly.

I have the folowing exercise (which I've been thinking quite a while and couldn't figure out):  Show that $\forall (x,y)$ in the first quadrant: $$\frac {x^2+y^2}{4}\leq e^{x+y-2}$$  My idea was to work with maxima and minima, but I'm stuck... Any help will be much appreciated!


Struggling with outputting huge text (around 500 KB) to a file on linux. Text contains spaces, special characters and other.... Getting error /bin/sh : argument list too long  #!/bin/bash txt="---huge text separated by line and containing special characters---" echo $txt   or  #!/bin/bash txt="---huge text separated by line and containing special characters---" echo $txt >> filename.txt

Or, an introductory guide to robust filename handling and other string passing in shell scripts.  I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some file names).  I encountered a problem such as the following:   I have a file name containing a space hello world, and it was treated as two separate files hello and world. I have an input line with two consecutive spaces and they shrank to one in the input. Leading and trailing whitespace disappears from input lines. Sometimes, when the input contains one of the characters \[*?, they are replaced by some text which is is actually the name of files. There is an apostrophe ' (or a double quote ") in the input and things got weird after that point. There is a backslash in the input (or: I am using Cygwin and some of my file names have Windows-style \ separators).   What is going on and how do I fix it?


I whant to know if the following proposition holds:  If $f$ is entire, and $p$ is a polynomial such that  $$|f(z)| \leq |p(z)|,\forall z \in \mathbb{C}, $$ then  there is $c \in \mathbb{C}; f(z)=cp(z)$.  If it is true, how to prove it?

Suppose $f$ and $g$ are entire functions with $|f(z)|\leq|g(z)|$ for all $z$.  How can we show that $f=cg$ for some complex constant $c$?  Thanks for any help :)


My file is a .txt file and all comments have no spaces before them.  I have a file with 10,000 lines that looks like this and I am reading every line of the file.  ## something ## something ## something 12312312 123123 12312312 123123 123123   However, my code will fail if there is not a value in every line.  Is there a way in Python to exit the program if the line is blank?  I just need a simple If statement to fix my program.  Something like   if line == blank:     quit

I am aware of the die() command in PHP which exits a script early.  How can I do this in Python?


I'm a new user of mixed models and through the material I've been reading there are always probability values (p>t) or (p>z) that estimate the importance of a level of a factor in the model. However, when using the lmer() function in R, which supposedly gives you those probabilities, I simply don't find them. Here is the output:   Linear mixed model fit by REML  Formula: Temp ~ depth + (1 | locality)     Data: qminmatrix     AIC   BIC logLik deviance REMLdev  561.3 581.3 -273.7    551.5   547.3 Random effects:  Groups   Name        Variance Std.Dev.  locality (Intercept) 4.7998   2.1909    Residual             4.0433   2.0108   Number of obs: 128, groups: locality, 4  Fixed effects:             Estimate Std. Error t value (Intercept)  22.0103     1.1500  19.140 depth1        1.9564     0.6832   2.864 depth10       2.6624     0.5756   4.625 depth5        3.0209     0.4932   6.125 depthWS      -2.2585     0.5444  -4.149  Correlation of Fixed Effects:         (Intr) depth1 dpth10 depth5 depth1  -0.157                      depth10 -0.175  0.189               depth5  -0.213  0.313  0.458        depthWS -0.191  0.334  0.373  0.441

I use lme4 in R to fit the mixed model  lmer(value~status+(1|experiment)))   where value is continuous, status and experiment are factors, and I get  Linear mixed model fit by REML  Formula: value ~ status + (1 | experiment)    AIC   BIC logLik deviance REMLdev  29.1 46.98 -9.548    5.911    19.1 Random effects:  Groups     Name        Variance Std.Dev.  experiment (Intercept) 0.065526 0.25598   Residual               0.053029 0.23028  Number of obs: 264, groups: experiment, 10  Fixed effects:             Estimate Std. Error t value (Intercept)  2.78004    0.08448   32.91 statusD      0.20493    0.03389    6.05 statusR      0.88690    0.03583   24.76  Correlation of Fixed Effects:         (Intr) statsD statusD -0.204        statusR -0.193  0.476   How can I know that the effect of status is significant? R reports only $t$-values and not $p$-values.


What assumptions must be fulfilled in quantile regression?

The question has been asked (one time) on CV before, but the answer is really imprecise and does not really answer the question in my opinion.  So: What are the assumptions for estimating a linear regression model via quantile regression?  To my understanding (and as several CV users have mentioned), quantile regression does not assume any specific distribution of the error terms - does that mean that, in a time series model, autocorrelation and heteroscedasticity do not have to be accounted for?  What about the other Gauss-Markov assumptions? I would assume that the assumption of no perfect multicollinearity has to be met when applying quantile regression, but do the parameters have to be linear? The linearity assumption only has to hold for the specific quantile I would assume.  Anyways - I do not find any backup for any of my thoughts in the scientific literature and I would appreciate a comprehensive answer. Thank you!


I have Ubuntu 12.04 right now. For reasons I would like to switch back to windows 7. (Even though I love Ubuntu.) I was wondering if anyone could point me in the direction of a guide on how to do this? I do not want to keep Ubuntu. I have a flash drive and an external hard drive and I can use either or for the boot. I would like to wipe the whole computer to use windows 7, I also have the product key for it. Any feedback is great, thanks.

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


I didn't house her, but I can't now because she died in the dungeon.  Will she spawn again?

I read on the wiki that people will move in under the following conditions:   You do something to please them An empty house is available with a light source, table, and chair (also with walls).   I have a house which is about 7x8, then a roof space above that; about half the area. I could put furniture up there too, but will anyone move in?


I have GRIB2 files that seem to be in a projection similar to EPSG: 4326, except that instead of longitude between -180 and +180 it is between 0 and 360.   My intention is to get these files into geoserver and allow the data to be queried and reprojected at will through the WMS. I can get these files into geoserver with the GRIB extension, but I get a null pointer error when I attempt to reproject to mercator. I assume that this error occurs because data lies outside the -180 to +180 longitude bound.  I had attempted to just reproject the GRIB files with gdal_translate, using the PROJ4 +lon_wrap=180option, but that operation takes forever and produces a far larger output file for some reason.     From what I understand, I can fix this situation by creating a custom projection in user_projections/epsg.propertiesthat describes the CRS of these GRIB files. A custom projection for geoserver must be in the WKT format.  TL;DR: How do I write a WKT that describes a lat/lon coordinate system similar to EPSG: 4326 but with longitude ranging from 0 to +360 instead of -180 to +180?  Here is the gdalinfo for one of these GRIB files. The file depicts the continental United States:  Size is 2847, 1517 Coordinate System is: GEOGCS["Coordinate System imported from GRIB file",     DATUM["unknown",         SPHEROID["Sphere",6371229,0]],     PRIMEM["Greenwich",0],     UNIT["degree",0.0174532925199433]] Origin = (229.982699929725896,55.001944129287601) Pixel Size = (0.024600140548138,-0.023088258575198) Corner Coordinates: Upper Left  (     229.983,      55.002) (229d58'57.72"E, 55d 0' 7.00"N) Lower Left  (     229.983,      19.977) (229d58'57.72"E, 19d58'37.40"N) Upper Right (     300.019,      55.002) (300d 1' 9.48"E, 55d 0' 7.00"N) Lower Right (     300.019,      19.977) (300d 1' 9.48"E, 19d58'37.40"N) Center      (     265.001,      37.490) (265d 0' 3.60"E, 37d29'22.20"N)   gdalsrsinfo:  PROJ.4 : '+proj=longlat +a=6371229 +b=6371229 +no_defs '  OGC WKT : GEOGCS["Coordinate System imported from GRIB file",     DATUM["unknown",         SPHEROID["Sphere",6371229,0]],     PRIMEM["Greenwich",0],     UNIT["degree",0.0174532925199433]]   Screenshot from QGIS:   Edit: This is not a duplicate. I have seen the answer from the referenced question, and it is not satisfactory. The operation takes too long to complete and produces a file that is entirely too large.  Edit #2: Added a link to the GRIB file:

I have a geotiff raster image that has a coordinate system with longitudes from 0 to 360. The horizontal center of the image is 180 longitude. See image below:    I want to transform it to EPSG:4326 SRS with -180 180 longtitude range.  And I want the center of the image to be at Greenwich meridian (0). I guess this srs is very widely used. I expect the result look like this:    So I use a gdalwarp command to reproject:  gdalwarp -s_srs '+proj=latlong +datum=WGS84 +pm=180dW' -t_srs EPSG:4326 test_col.tif test_4326.tif   But I only get a tiff with bigger dimensions (more pixels) and EPSG:4326 metadata. The image itself looks the same, as the initial one. But I expect it to swap the hemispheres.  How do I gdalwarp an image to be strictly -180 180 EPSG:4326 with the center in 0 longitude?  This is gdalinfo of my initial file:  Origin = (-0.102272598067084,89.946211604095552) Pixel Size = (0.204545196134167,-0.204423208191126) Metadata:   AREA_OR_POINT=Area Image Structure Metadata:   INTERLEAVE=BAND Corner Coordinates: Upper Left  (  -0.1022726,  89.9462116) (  0d 6' 8.18"W, 89d56'46.36"N) Lower Left  (  -0.1022726, -89.9462116) (  0d 6' 8.18"W, 89d56'46.36"S) Upper Right (     359.897,      89.946) (359d53'50.18"E, 89d56'46.36"N) Lower Right (     359.897,     -89.946) (359d53'50.18"E, 89d56'46.36"S) Center      ( 179.8975000,  -0.0000000) (179d53'51.00"E,  0d 0' 0.00"S)   This is gdalinfo after gdalwarp     Origin = (-180.102727401932952,89.946211604095552) Pixel Size = (0.091397622896436,-0.091420837939082) Metadata:   AREA_OR_POINT=Area Image Structure Metadata:   INTERLEAVE=PIXEL Corner Coordinates: Upper Left  (-180.1027274,  89.9462116) (180d 6' 9.82"W, 89d56'46.36"N) Lower Left  (-180.1027274, -89.9699975) (180d 6' 9.82"W, 89d58'11.99"S) Upper Right ( 179.8211116,  89.9462116) (179d49'16.00"E, 89d56'46.36"N) Lower Right ( 179.8211116, -89.9699975) (179d49'16.00"E, 89d58'11.99"S) Center      (  -0.1408079,  -0.0118929) (  0d 8'26.91"W,  0d 0'42.81"S)


This question is about Klein-Gordon theory (the field is hermitian).  If I calculate the amplitude for the process $\phi\to\phi$, I get two different results depending on whether I use Feynman rules or the LSZ formula.  For example, if I use the Feynman rules, I get $$ p_\text{in} ---\blacktriangleright ---p_\text{out} \qquad\Longrightarrow\qquad \mathcal A=\frac{1}{p_\text{in}^2-m^2}=\frac{1}{p_\text{out}^2-m^2} $$  On the other hand, according to the LSZ reduction formula, the amplitude is (supposedly) given by $$ \langle f|i\rangle=\int\mathrm dx\,\mathrm dy\ \mathrm e^{-ip_\text{in}x}\mathrm e^{ip_\text{out}y}\ \Box_x \Box_y \langle \phi(x)\phi(y)\rangle $$ where $\Box_x=\partial^2_x+m^2$ , and $\langle\phi(x)\phi(y)\rangle$ is the propagator. As we know that the Klein-Gordon operator, when acting on the propagator, gives a delta function (i.e. $i\Box_x \langle\phi(x)\phi(y)\rangle=\delta(x-y)$), the amplitude is easly calculated, and equals $$ \langle f|i\rangle=i(2\pi)^4\delta(p_\text{in}-p_\text{out})(p_\text{in}^2-m^2) $$ which means that $\mathcal A=p_\text{in}^2-m^2=p_\text{out}^2-m^2$.  Can anybody tell me where is my mistake? I believe that the right result is the first one, so maybe my formula for LSZ is wrong, or cannot be used in a one-particle process?

I am trying to learn how to calculate scattering amplitudes in a Klein-Gordon theory. I am getting stuck with the simplest of the examples: $\phi\to\phi$ in a free scalar-field theory.  If I calculate the amplitude for the process $\phi\to\phi$, I get two different results depending on whether I use Feynman rules or the LSZ formula.  Let's say that the incoming particle has momentum $p_\mathrm{in}$ and that the outgoing one has momentum $p_\mathrm{out}$. Then a simple Feynman diagram gives amplitude = propagator, that is,  $$ p_\mathrm{in} ---\stackrel{p}{\blacktriangleright} ---p_\mathrm{out} \qquad=\qquad \frac{1}{p^2-m^2} \tag{1} $$ where $p$ is the momentum of a virtual particle connecting the in and out states. From momentum conservation, $p_\mathrm{in}=p=p_\mathrm{out}$.  From $(1)$ we get that the amplitude for $\phi\to\phi$ is $$ \mathcal A=\frac{1}{p^2_\mathrm{in}-m^2}=\frac{1}{p^2_\mathrm{out}-m^2} $$  If, on the other hand, we calculate the amplitude for the process with the LSZ reduction formula, we get  $$ \mathcal A(2\pi)^4\delta(p_\mathrm{in}-p_\mathrm{out})=i\int\mathrm dx\,\mathrm dy\ e^{ip_\mathrm{in}x} e^{-ip_\mathrm{out}y}\, \square_x \square_y \langle\phi(x)\phi(y)\rangle $$ where $\square_x\equiv \partial_x^2+m^2$, and $\langle \phi(x)\phi(y)\rangle$ is the propagator. As the KG derivative, when acting on the propagator, results in a delta, i.e., $i\square \langle\phi(x)\phi(y)\rangle=\delta(x-y)$, this integral evaluates to $$ \begin{align} \mathcal A (2\pi)^4\delta(p_\mathrm{in}-p_\mathrm{out})&=\int\mathrm dx\,\mathrm dy\ e^{ip_\mathrm{in}x} e^{-ip_\mathrm{out}y}\, \square_x \delta(x-y)\\ &=(2\pi)^4\delta(p_\mathrm{in}-p_\mathrm{out})(p_\mathrm{in}^2-m^2) \end{align} \tag{2} $$  From $(2)$ we get $$ \mathcal A=p_\mathrm{in}^2-m^2=p_\mathrm{out}^2-m^2 $$  Comparing this to the amplitude from the diagram, we find that the results disagree. Can anybody tell me where is my mistake? I believe that the right result is the first one, so maybe my formula for LSZ is wrong, or cannot be used in a one-particle process?


It has been noted in other questions and answers on this site that Tolkien's conception of Middle-Earth has an imaginative relation to Earth history. Some salient sections of Tolkien quotes from answers to  are worth repeating here for background:                    Then a final one from an answer on :        So the question is does Tolkien ever express in his own words that he himself is still living in "Middle-earth"—in an imaginative sense, I would suspect, but one in which Tolkien's time (A.D. 1892-1973) and place (Britain/Europe) he refers to as Middle-earth, rather than Earth or Europe, etc.?   Another way to state this is if Tolkien conceives the identity of what he calls "Middle-earth" as passed away, and what remains during his time is no longer Middle-earth, but simply Earth—or does he view "Middle-earth" as still continuing in his day.  Some might ask why this matters. It matters in determining the "voice" Tolkien might use in his narration of events, specifically in a fundamental difference between what is plausible for how Tolkien would voice a narrative aside in his writing, which is the basis for  (and a difference in view on his voice as ). So an answer here could resolve the validity of that answer to my question.  Clarifying How this is a Distinct Question  This question has been closed as a duplicate to one that it had linked to as background. But that other question is a very distinct question from this one.   is asking about whether Tolkien conceived of Middle-earth being a part of "our Universe." It was a question about where Tolkien imagined the stories of Middle-earth taking place. Fundamentally, it was a question about how he conceived his world of Middle-earth.  This question is asking how Tolkien conceived of himself in relation to his world. That is, did he perceive Middle-earth to be continuing as Middle-earth during his own time period, such that he was himself still living in Middle-earth.

I started reading The Hobbit to my daughter last night having read most of Tolkien's books in my youth, but haven't read them again for some years.  In the first few pages of The Hobbit, Tolkien talks about Hobbits being less common 'these days' such that 'big folks like us' probably don't know much about them. Taken in isolation, these first few pages strongly imply that the events take place in our world, presumably many many years ago.  However, this isn't the impression one gets from any of the other books, as far I can remember. Particularly The Silmarillion presents a creation story that takes some elements of the Ambrahamic faiths' creation stories, but is clearly a different story. I don't get the impression that Tolkien intends these other stories to be about our world.  What was Tolkien's likely meaning behind this passage?


first I'm going to explain the situation and then the problem.  I'm designing a table with some data and I developed some functions for ordering this data when the "th" tag of the column is clicked.  $('#table_id > thead > tr > th').click(function() ... //ordering algorithm    In addition, I created 2 "select" tags for filtering the data of the tables. The method I'm using for filter data is to search for the text that matches the select text and use remove() method for deleting the row.   document.getElementById("select_id").addEventListener("change", function() { //remove rows   When the data is filtered (by the select) and I try to click the "th" tag of the column the "click" method is not working and I have no error messages in the console, so I don't know how to solve it.  Any one knows is "click" method changes it's functionallity when the page content changes?  Thanks for reading. If more code is needded for understanding the problem I will paste it.

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I've set my grandson's laptop to be able to dual boot (Vista and Ubuntu). I'd like to give as much space as possible to Ubuntu as Windows isn't used much. I'm  pretty noob to Linux and have no real idea how to use gparted.  Here is a screenshot of gparted; it'd be great if someone could explain what it means and how to give more space to Ubuntu and less to Windows.

Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers.  Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions).  Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space.  How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions?


In the following code, shouldn't x be considered a global variable?  Thus, when it gets to the console.log line x it should have the value of "World".  However, when I run this code it logs "Hello undefined".  `  let x = "World";  function sayHello(x) {     console.log("Hello ", x); }  sayHello();   But when I change the parameter to y, it then works as I expected, logging "Hello World.  let x = "World";  function sayHello(y) {     console.log("Hello ", x); }  sayHello();   Can someone explain what is going on here?  thanks

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


I've never learned Java, but I need to understand what the following piece of code means, the main question is the curly braces:  /**  *   This Universe uses the full HashLife algorithm.  *   Since this algorithm takes large steps, we have to  *   change how we increment the generation counter, as  *   well as how we construct the root object.  */ public class HashLifeTreeUniverse extends TreeUniverse {    public void runStep() {       while (root.level < 3 ||              root.nw.population != root.nw.se.se.population ||              root.ne.population != root.ne.sw.sw.population ||              root.sw.population != root.sw.ne.ne.population ||              root.se.population != root.se.nw.nw.population)          root = root.expandUniverse() ;       double stepSize = Math.pow(2.0, root.level-2) ;       System.out.println("Taking a step of " + nf.format(stepSize)) ;       root = root.nextGeneration() ;       generationCount += stepSize ;    }    {       root = HashLifeTreeNode.create() ;    } }   Specifically this statement in the bottom of the listing:     {       root = HashLifeTreeNode.create() ;    }   It looks like a method without a signature, what does it mean?  Thank you in advance!

I have some Java code that uses curly braces in two ways  // Curly braces attached to an 'if' statement: if(node.getId() != null) {     node.getId().apply(this); }  // Curly braces by themselves: {     List<PExp> copy = new ArrayList<PExp>(node.getArgs());     for(PExp e : copy)     {         e.apply(this);     } } outAMethodExp(node);   What do those stand-alone curly braces after the first if statement mean?


I find that I often hit the Windows key by accident and it opens the "search your computer" and freezes up my computer for 5 or 10 seconds.  How do I disable the Windows key?  Ubuntu 16.04 LTS

I want to disable the Super key, when I press Super nothing should happen.  How can I do that?


Question: Are there $2^{\aleph_{0} }$ sets of natural numbers such that each two have finite intersection.  From what I've read about infinite families, I need to ignore those who have the properpty $P$.  Property $P$: the family is threadless, but whenever we take finitely many sets from the family, those sets have infinite intersection.  and probably find ones with property $T$.  Property $T$: the family is threadless, and it is an “almost-tower”: Whenever you pick two sets in the family, one of them is almost-contained in the other. - probably meaning that we can find such an intersection which is finite, because members are contained in each other.  Then I thought..  To find them, I should think of rational numbers instead of natural numbers, remembering that rational numbers can be paired up with natural ones, so solving this problem for families of rational numbers is the same as solving it for families of natural numbers. Now, I need to consider various ways of defining the real numbers.  And I'm stuck.. any help is appreciated.

Prove the existence of uncountable family $\{X_i \subseteq \mathbb{N}\}_{i \in \mathbb{R}}$ such that intersection of any $k$ sets from this family is infinite and intersection of any $k+1$ sets is finite. $k \ge 2$, $\mathbb{N}$ means natural numbers, $\mathbb{R}$ means real numbers.


I'm trying to read a text file line by line within my HTML/Javascript web page.    The text file I want to read is in the "data" folder in the web page directory. To read the text file, I'm using FileReader and BufferedReader within my script tags.    I'm getting an error "Uncaught syntax error: Unexpected identifier" on the line where I create the FileReader with the file path, see code below.  I thought the problem might be that these were Java objects so perhaps I needed to import those. I tried to add:  import java.io.FileReader; and import java.io.BufferedReader;   but then got an      "Unexpected identifier"   error for      "import java.io.FileReader;   "  FileReader tidewatchDataOutput = new FileReader("data/test.txt"); BufferedReader bufferSCHISMDataReader = new BufferedReader(tidewatchDataOutput);   The web page is no longer loading properly in Chrome as it did before; it just stops in the middle.

I need to do an  request in JavaScript. What's the best way to do that?  I need to do this in a Mac OS X dashcode widget.


Is there a reason for the fact that Area 51 is not available on mobile? Will Area 51 be available on the mobile version of the SE app soon?

I am trying to use Stack Exchange Andoid App to use my accounts in Stack Overflow & Area 51.   For the Area 51, there is only Area 51 Discussion. Even Area 51 Discussion isn't working in the App!   VERSION 1.0.51  When adding this site, it's showing the correct full name as in this screen-shot:     However, when I pin this site to my fav sites in Stack Exchange, it is showing: Unknown Site. When clicking it, it shows black screen then just quit the App!  Here is the screen-shot:       Is the site not yet capable with Android? or is it a bug in the App itself?  PS: this question isn't duplicate:   In the previous versions of the App, the site was opening but with Unknown Site name. However, in this version, it quits the app when pressing the area site! It isn't opening at all! This question is also to track this bug in the App. As it's about the site name issue & the content as well.


whenever I am sudo I ma getting errors --> E: Type 'sudo' is not known on line 2 in source list /etc/apt/sources.list.d/balena-etcher.list E: The list of sources could not be read. E: Type 'sudo' is not known on line 2 in source list /etc/apt/sources.list.d/balena-etcher.list E: The list of sources could not be read. I don't know what should I do please help me

Every once in a while I see users having issues to update due to errors like this:  E:Type 'ain' is not known on line 1 in source list /etc/apt/sources.list.d/some-ppa.list'   with varying types/line numbers/source list files (often after removing a PPA).  How can such an error be fixed?


One of the postulates special relativity is that "The laws of physics are the same in all inertial frames of reference." What is meaning of this statement? If it is talking about physical laws  I do not understand why  because the laws of physics do not depend of the observer, for example , Maxwell equation is Maxwell equation  in  a accelerated frame or in a inertial frame. If it talk about observation let us take the example of an source emitting light of frequency $\nu$ .Due to the doppler effect a static observer in relation to the source and one moving with velocity $v$ in relation to the source will see different frequencies and so different observation. So what is the meaning of this statement?

In the first paragraph of Wikipedia's article on , it states one of the assumptions of special relativity is     the laws of physics are invariant (i.e., identical) in all inertial systems (non-accelerating frames of reference)   What does this mean? I have seen this phrase several times, but it seems very vague. Unlike saying the speed of light is constant, this phrase doesn't specify what laws are invariant or even what it means to be invariant/identical.   My Question   Can someone clarify the meaning  of this statement?   (I obviously know what an inertial frame is)


I have a tourist multi entry C visa (Etats Schengen) from the Swiss consulate in the U.S and was wondering the following below:  1) Can I travel to other Schengen countries without any issues given I have     obtained the tourist visa from Swiss consulate.  2) Do I have to enter Switzerland since my tourist visa was provided by the     Swiss consulate and then book my flight/train to other Schengen     countries?  3) Can I fly into another Schengen country without having to fly into     Switzerland?  4) Do I have to fly out of Switzerland to come back home to the U.S since     the tourist visa was provided to me by the Swiss consulate or can I fly     out from another Schengen country back home to the U.S?  Please provide me some form of assistance as I need to book my trip itinerary accordingly and as soon as possible.  Thank you.

In case, if I get a multiple-entry Schengen visa in one of the embassies in Ukraine, Kyiv - should my first trip be to the country which issued the visa?  Any there any requirements of this sort? Does this condition vary depending on embassy which issued the visa?  What are the possible consequences on not visiting that country first? Does it somehow depend on country where the embassy is (i.e. non-Schengen and not EU members)?


I think i didnt explain this well, this is edited. {"code":200,"meta":"{item:{Title:'{\"text\":\"This is title.\"}', Description:['Description']}}","name":"Awesome Sword's Information","id":10442}  I want to get this object's meta. but I only could get {item:{Title:'{"text":"This is title."}', Description:['Description']}}. How can I convert this string to javascript object? Thanks.

Given a string of JSON data, how can I safely turn that string into a JavaScript object?  Obviously I can do this unsafely with something like:  var obj = eval("(" + json + ')');   but that leaves me vulnerable to the JSON string containing other code, which it seems very dangerous to simply eval.


As the title says: Prove that any two real finite dimensional vector spaces with the same dimension are isomorphic to one another?  How would you approach this proof?

Given the following problem     Let $U$ and $V$ be finite dimensional vector spaces, such that $\dim(U) = \dim(V)$. Prove that $U$ and $V$ are isomorphic.   I was just wondering if somebody could critique and validate my proof.  Proof  Two vector spaces $U$ and $V$ are isomorphic if and only if there exists a bijection $\phi: U \to V$. That is, an invertible linear map between the two. Let $\dim(U) = \dim(V) = n$ and let $\left\{u_1, \dots, u_n\right\}$ and $\left\{v_1, \dots, v_n\right\}$ be bases for $U$ and $V$, respectively. It follows that any vector $u \in U$ can be written as  $$ u = c_1u_1 + \cdots + c_nu_n $$  We define $\phi: U \to V$ as  $$ \phi(c_1u_1 + \cdots + c_nu_n) = c_1v_1 + \cdots + c_nv_n $$  Observe that $\phi$ is invertible. That is, given a vector  $$ v = d_1v_1 + \cdots + d_nv_n $$  in $V$, we define $\phi^{-1}: V \to U$ as  $$ \phi^{-1}(d_1v_1 + \cdots + d_nv_n) = d_1u_1 + \cdots + d_nu_n $$  Since there exists a bijection between $U$ and $V$, they are isomorphic.


can i update table and set JSON string with PDO? Because PDO is removing "\" character and diacritics is not working please help.  ->query("UPDATE products SET name = '".$new_name."' WHERE shop = '1' AND id = 'a9t8'");

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


How to restrict HTML content while pasting some text from a website to our EditText?.   Example I copy some text from a website, when I paste the text in my EditText the HTML font and text size also comes along. What i want is to restrict any HTML content while I paste the text. Tried several methods using TextWatcher and InputFilters, but none of them are working. Whatsapp is handling it somehow. Please help.  Edit: The string can be converted to non-HTML but how to make changes in EditText?

Is there a good way to remove HTML from a Java string? A simple regex like replaceAll("\\<.*?>", "")   will work, but things like &amp; wont be converted correctly and non-HTML between the two angle brackets will be removed (i.e. the .*? in the regex will disappear).


For any nonzero integers $ a $ and $ b $, there exist integers $ s $ and $ t $ such that $ \gcd(a,b) = as + bt $. Moreover, $ \gcd(a,b) $ is the smallest positive integer of the form $ as + bt $.  I know of one proof of this question, in which we consider $$ S = \{ am + bn ~|~ \text{$ m,n \in \mathbb{Z} $ and $ am + bn > 0 $} \}, $$ but I didn’t manage to get the proof. Can someone please explain this theorem?

Given $a_1, a_2, a_3, \ldots , a_n$ not all zero, show $\gcd(a_1, a_2, a_3, \ldots , a_n)$ is the least positive integer that can be expressed in the form $a_1x_1+a_2x_2+ \ldots +a_nx_n$. Also deduce $a_1x_1+a_2x_2+ \ldots +a_nx_n = b$ has solutions $\iff \gcd(a_1, a_2, a_3, \ldots , a_n)|b$.   I know that $ax+by=n$ has integer solutions $\iff \gcd(a,b)|n$. I'll need to use induction to show $a_1x_1+a_2x_2+ \ldots +a_nx_n = \gcd(a_1, a_2, a_3, \ldots , a_n)$ has solutions, and then I will be able to say that as $\gcd(a_1, a_2, a_3, \ldots , a_n) | a_1x_1+a_2x_2+ \ldots +a_nx_n $ for any $x_1,x_2, x_3 \ldots x_n$ then $c \leq \gcd(a_1, a_2, a_3, \ldots , a_n)$ and $c \geq \gcd(a_1, a_2, a_3, \ldots , a_n)$, and thus $c=\gcd(a_1, a_2, a_3, \ldots , a_n)$.


Can someone please list all the image formats (.jpg, .png, .gif, etc.) that most modern browsers will accept and render?

JPEG, GIF and PNG can be displayed with the img tag and will work in all browsers, the object element can be use for displaying images specifying its MIME type, but what other graphic formats are supported by img or object tag in most browsers without installing plugins? (TIF, SVG, PCX, PICT, etc..)


Whenever we try to serialize an object of a Class, we always have a unique value for serialVersionId as a private final field, what is its significance with respect to deserialization, can we use it to check whether the object and the values have been deserialized in a proper way ?

Eclipse issues warnings when a serialVersionUID is missing.       The serializable class Foo does not declare a static final   serialVersionUID field of type long   What is serialVersionUID and why is it important?  Please show an example where missing serialVersionUID will cause a problem.


The  for Google Earth says this:     Note to 64bit users: The 64bit debian package depends on ia32-libs   which is deprecated and no longer available as of 13.10 Saucy. Use the   32bit package and multiarch-support.   Where is this multiarch-support and how can I ensure it is installed?  This is for a re-installation of the 64-bit version. The Software Updater lists  main under the 'Other Software' tab. Does that mean multiarch-support is set to update as part of that?  (Ubuntu 14.04 LTS, Nvidia GeForce 430 using Nvidia binary driver v. 331.113)

I installed Ubuntu 14.04 and the current Android development SDK, which contains 32-bit executables. I found that I cannot run those 32-bit binaries. Trying to start them from bash gives me an error: $ ./adb bash: ./adb: No such file or directory  It is there though: $ ls -al ./adb -rwxrwxrwx 1 thomas thomas 1231255 Jan 17 13:31 ./adb $ file ./adb ./adb: ELF 32-bit LSB  executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.8, not stripped.   Same symptom for all the other 32-bit tools in the Android SDK. In olden days one could just install 32-bit libraries on 64-bit Ubuntu to get 32-bit support, but that does not seem to work anymore. How do I run 32-bit apps on a 64-bit Ubuntu distribution?


I was playing aroun and found interessting thing  var x = "x"; function a (){     var x = "y";   if(1){     var x = "g";     alert(x);   }   alert(x) }  a()   why does this output "g" , "g"  insted of "g" , "y" ? The if creates another block scope and x is local variable inside it which means when i get out of the if block , the outer x ( which equals "y" ) should be printed.

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


So I have the following tables:  Table 1  fname    mi    lname    empid  John     A     Smith    1202 Bob            Doe      9815   Table 2  unid    empid  1015     1202 1015     9815   Table 3  unid    Item  1015    ABC 1015    DEF   My intended output should be (when supplying unid=1015)  fname    mi    lname    item  John     A     Smith    ABC, DEF Bob            Doe         Now that would be the ideal, but I'm more than happy to deal with the repeated [Item] values on the front end.    My current statement is:  select p.FNAME,p.MI,p.LNAME, ac.EQUIP from table1 t1, table2 t2, table3 t3   where t1.EMPID = t2.EMPID and t2.UNID = t3.UNID and t2.unid = '1015' group by t1.FNAME, t1.MI,  t1.LNAME,t3.EQUIP   For the life of me, I cannot figure out how get the values in item (which can be 0 or more to a maximum of 8) as one comma separated string.  My problem is, due to site/client constraints, I cannot use an SP but this has to be done in one SQL statement.  This is on SQL SERVER 2008 R2.

I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).  In the original app, we used almost entirely ANSI-SQL compliant statements, with one significant exception -- we used MySQL's group_concat function fairly frequently.  group_concat, by the way, does this: given a table of, say, employee names and projects...  SELECT empName, projID FROM project_members;   returns:  ANDY   |  A100 ANDY   |  B391 ANDY   |  X010 TOM    |  A100 TOM    |  A510   ... and here's what you get with group_concat:  SELECT      empName, group_concat(projID SEPARATOR ' / ')  FROM      project_members  GROUP BY      empName;   returns:  ANDY   |  A100 / B391 / X010 TOM    |  A100 / A510   So what I'd like to know is: Is it possible to write, say, a user-defined function in SQL Server which emulates the functionality of group_concat?   I have almost no experience using UDFs, stored procedures, or anything like that, just straight-up SQL, so please err on the side of too much explanation :)


Let’s take a normal operator $A$, and the spectrum of $A$ is ${0,1}$, then is $A$ necessary be a projector? That is, it’s both self-adjoint and $A^2=A$. I think $A^2=A$ is true, but don’t see why self-adjoint. If that’s not true, could you give a counter example? (I tried very hard on giving a counter example, but failed, that’s the reason now I doubt this actually is true)

Consider a normal operator on a complex Hilbert space with its spectrum contained in the real line. Show that the operator is hermitian without using the spectral theorem.  What I have tried- Since the spectrum is inside the real line, the boundary of the spectrum as a subset of the complex numbers is the spectrum itself. Hence the spectrum is equal to the approximate point spectrum. I have been unable to proceed further.


Suppose $S\subset[0,1]$ is countable, $f:[0,1]\to\Bbb R$ is continuous, and $f'(t)=0$ for every $t\in[0,1]\setminus S$. Does it follow that $f$ is constant?  Yesterday I realized the answer's yes if $S$ is closed and $f$ has bounded variation (say $f(x)-f(0)=\mu([0,x])$. Then $\mu$ must be concentrated on $S$, and since $S$ is countable and $\mu$  vanishes on singletons it follows that $\mu=0$.)    I can show the answer's yes if $S$ is closed.   But.  (The answer must be yes: If there were a counterexample it would be in books next to or in place of that Lebesgue-Cantor function. But I fear some may feel this argument is somewhat lacking in "rigor"...)  Edit: Thanks to @MartinR for pointing out that this follows from the result . The answer there is a little intricate; one can get the idea  from the first few lines, and then give the following proof, which seems simpler to me (possibly just because stuff I figure out always seems simpler than stuff I try to read, maybe not):  Let $S=(\alpha_n)$. Let $\epsilon>0$.  If $x=\alpha_n$ there is an open interval $I_x$ with $x\in I_x$ and $$|f(s)-f(t)|<\epsilon2^{-n}\quad(s,t\in I_x).$$Otoh if $x\in[0,1]\setminus S$ there is an open interval  $I_x$ with $x\in I_x$ and $$|f(s)-f(x)|\le\epsilon|s-x|\quad(s\in I_x).$$  Now $[0,1]$ is covered by finitely many intervals $J_1,\dots,J_n$ with $J_j=I_{x_j}$. We can assume that no $J_j$ is contained in the union of the $J_k$ for $k\ne j$, and then we can assume that the $J_j$ are ordered from left to right; in particular $0\in J_1$ and $1\in J_n$.  Now $J_j\cap J_{j+1}\ne\emptyset$, since $[0,1]$ is connected. Say $y_j\in J_j\cap J_{j+1}$. Then $$|f(1)-f(0)|\le|f(0)-f(x_1)|+|f(x_1)-f(y_1)|+|f(y_1)-f(x_2)|+|f(x_2)-f(y_2)| \\+|f(y_2)-f(x_3)|+\dots+|f(y_{n-1})-f(x_n)|+|f(x_n)-f(1)|.$$Now for each term here we may apply one or the other of the two inequalities above (depending on whether $x_j\in S$); throwing in a lot of extra stuff on the RHS to simplify the notation we obtain $$|f(1)-f(0)|\le2\epsilon\sum_k2^{-k}+\epsilon\sum|x_j-y_j|+\epsilon\sum|y_j-x_{j+1}|\le 3\epsilon.$$  So $f(1)=f(0)$, which come to think of it is not what we wanted to prove, but the same argument shows $f(b)=f(a)$ for every $[a,b]\subset[0,1]$.

PROBLEM. Let $f:[a,b]\to\mathbb R$ be a continuous function, such that $f'(x)\ge 0$, for all $x\in [a,b]\setminus A$, where $A\subset [a,b]$ is a countable set. Show that $f$ is increasing.  Attention. In this problem, we DO NOT assume that $f$ is differentiable in the whole $[a,b]$.  Notes. (1) If we assume that $f$ is differentiable in the whole interval, then we can easily show that $f'(x)\ge 0$, everywhere. For otherwise, if $f'(x_0)=c<0$, for some $x_0\in [a,b]$, then by virtue of , $(c,0)\subset f'([a,b])$, and hence, $f'(x)<0$, for uncountably many $x$'s.   (2) The conclusion of the problem does not hold if we replace the assumption $A$ is countable with $A$ is a set of measure zero. Take for example the , with a negative sign in front.  (3) If the hypothesis $f'(x)\ge 0$, is replaced by $f'(x)=0$, then the conclusion becomes f is constant.


I observed the word "darkweb" in newspapers of late, and wondered if it is one word or two words. I could not get a definite answer when I did a Google search. No one seems to have addressed this issue. Now, my specific question is, which is acceptable usage? - "darkweb", "dark-web" or "dark web"?

Some compound words are written without hyphens (nonaggression, nonbeliever), some with hyphens (well-intentioned), and others with spaces (post office).  Is there a rule or good guide as to which option should be used?


There is a room having 100 people. There is a box with letters containing names of 100 people on it. No two people have same name. Everyone is supposed to pick one letter and keep it.   What is the probability that someone will pick the letter with his own name?

I can't really understand how the recursive formula for derangements is derived, i.e I can’t see how the patterns of it occur.  From Wikipedia:      Suppose that there are $n$ persons who are numbered $1, 2, \ldots, n.$   Let there be $n $hats also numbered $1, 2, \ldots, n$. We have to find the   number of ways in which no one gets the hat having same number as   his/her number. Let us assume that the first person takes hat $ i$.   There are $n − 1$ ways for the first person to make such a choice.   There are now two possibilities, depending on whether or not person $i$   takes hat $1$ in return:      Person $i$ does not take the hat $1$. This case is equivalent to   solving the problem with $n − 1$ persons and $n − 1$ hats: each of the   remaining $n − 1$ people has precisely 1 forbidden choice from among   the remaining $n − 1$ hats (i's forbidden choice is hat 1). Person $i$   takes the hat $1$. Now the problem reduces to $n − 2$ persons and  $n − 2$    hats. From this, the following relation is derived:      $!n = (n - 1) (!(n-1) + !(n-2)). $          In this particular example I do not understand why we take care of the case when person $i$ takes hat $1$ or not. When I think about derangements I see that the first person has $n-1$ choices, so the rest of the people, but, and here's another conceptual problem, how do we know that if we continue to count like this   the last person, as it's only and one choice, won’t have a hat of the same number?  Also, how would one calculate derangements with the formula above? I am a visual learner, so if you can provide some kind of mental images to help the understanding of the concept I would appreciate more.  (I've checked if this question was a duplicate but i didn't find other questions asking for some kind of intuitive argument for derangements.)


I'm trying to work out sum of this series $$1 + \frac{2}{2} + \frac{3}{2^2} + \frac{4}{2^3} + \ldots$$  I know one method is to do substitutions and getting the series into a form of a known series. So far I've converted the series into $$ 1 + \frac{2}{x} + \frac{3}{x^2} + \frac{4}{x^3} + \ldots  $$ where $x=2$ and I'm trying to get it into the form of the $\ln(1+x)$ series somehow. I have tried differentiating, integrating and nothing is working out. The closest I got is by inverting which gave me $ 1 + \frac{x}{2} + \frac{x^2}{3} + \frac{x^3}{4} \ldots $   Now I'm just lost and have no idea what to do.  The other idea I had was converting it into $$ \Large{\sum_{n=1}^\infty{\frac{n}{2^{n-1}}}}, $$ but I have no idea how to do anything further to it. How would you do this? Thnx.

How can I evaluate $$\sum_{n=1}^\infty\frac{2n}{3^{n+1}}$$? I know the answer thanks to , but I'm more concerned with how I can derive that answer. It cites tests to prove that it is convergent, but my class has never learned these before. So I feel that there must be a simpler method.  In general, how can I evaluate $$\sum_{n=0}^\infty (n+1)x^n?$$


First, I don't want this:   When I say color palette, I mean the real scheme/palette, not just foreground+background.  I want to change the definition of "dark red", "light green", etc... so the palette shown on the Colors tab of Properties.  Imagine I'm colorblind and don't see the difference between "red" and "green" and I want to change "red" to be the commonly agreed color of "yellow" for example. So any application that prints a red text will actually display as yellow in that command window.  It means that whenever an application prints something in color, the custom palette will be used. Note: I'm already using . Say I'm running  and I'm looking for a setting that will make it look different from the rest of the world :)

Few years ago, I changed color scheme of command prompt. Now, I have forgotten how exactly I did this.   It's permanent. So, COLOR command is out of question. It's intact no matter from where I launch cmd. So, changing color from shortcut properties is out of question because I get the color scheme even when I launch cmd from Run or from original location. It doesn't let me override it by shortcut properties. And, this is the problem. I create a cmd shortcut and change its color scheme from properties. But, this isn't reflected even after reboot.   So, the only option I have left: Use the same method I used few years ago. How did I change cmd color?


So using the following code: try (BufferedReader br = new BufferedReader(new FileReader("Program10.txt"))) { String sCurrentLine; String[] splits;              while ((sCurrentLine = br.readLine()) != null)  { splits = sCurrentLine.split("\\s+"); } } catch (IOException e)  { e.printStackTrace(); } System.out.println(splits); // prints as null  I've read the file, Program10.txt, by line to get: [1000  31000  3 Texas,  1042  12180.06  3 Texas,  1062  13240.45  2 Texas,  1200  36000  2 Maryland,  1327  19800.56  2 Alaska,  1483  22458.23  7 Texas, ... ]  And I'm hoping to print the entire line when the income (so the second element is greater than average income, which is 5,037) with the following code (***I suspect the problem is with the bolded code): ArrayList<Household> households = new ArrayList<Household>(); **// This will create new household object Household household = new Household( Integer.parseInt(splits[0]),  Double.parseDouble(splits[1]),  Integer.parseInt(splits[2]),  splits[3]);  I'm getting a null Exception in thread "main" java.lang.NullPointerException at Program10.readFile(Program10.java:129) (line 129 corresponds to the code "Integer.parseInt(splits[0]), " Is there something obvious I'm missing here?

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I have to set up an index of persons. Many have birthplaces with duplicate names, e.g. Immanuel Kant was born in Königsberg which nowadays is named Kalinigrad. So his entry would look like:  Kant, Immanuel (Königsberg/Kaliningrad 1724 – Königsberg/Kalinigrad 1804)   Now I try to achieve an automatic linebreak if necessary after "Königsberg/". I know normally i could use two quotes "" to have it split like this:  Kant, Immanuel (Königsberg/ Kaliningrad 1724 – Königsberg/  Kaliningrad 1804)   But this doesn't work. My WE:  \documentclass{scrbook} \usepackage[T1]{fontenc} \usepackage[ngerman]{babel} \usepackage[texindy, splitindex]{imakeidx} \makeindex[program=texindy,options=-L german-DIN]   \makeindex[name=pw, title=Personen und Werke, columns=2, intoc] \newcommand\pwindex[1]{\index[pw]{#1}}  \begin{document} Word\pwindex{AAAAAAA BBBBB/CCCCCC/DDDDD/EEEEE/FFFFF}               \printindex[pw]                                       \end{document}

I am using a number of items in text that are divided with a slash. For example dates in different calendars or names of locations, such as 585/1190~CE (the first number is the year in Islamic lunar calendar, the second is according to the Common Era calendar), or Mosul/al-Mawsil (the first is a common English spelling, the second is the transliteration of the original name).  The problem I am running into is that Latex cannot split such items when they are at the end of a line---and such item ends up sticking through the margins. Adding spaces around the slash helps, but it looks ugly and this is not how it is supposed to be in academic writing. I wonder if there is a workaround to solve this issue. Namely, I do not want to use spaces around "/", but I would like Latex to break an item after a slash when necessary.


I am trying to install net-tools using sudo apt install net-tools  but I get Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package net-tools  So I tried the following commands sudo apt update  sudo apt upgrade  sudo apt dist-upgrade sudo apt -f install sudo apt autoremove  each of them respond with Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.  any suggestions to fix this issue without breaking the server would be appreciated!

There are now errors when updating and I cannot install most software due to a corrupted  /etc/apt/sources.list   file. Is there a copy I can download to replace it?  The file would be for Ubuntu 12.04 (Final Beta) in the United States.


My question is similar to , but I am gearing mine more toward which edition to use.  In the past places I've worked, these decisions were made by other teams, and now I'm being asked to advise.    Edition: Do most sites consider it satisfactory to have a Developer edition running in DEV, QA, and STAGE environments, and then only run Enterprise Edition in Production?  I'm specifically referring to server products such as BizTalk (2010/2013) and SQL Server (2008/R2 and 2012).   In other words, if some software runs on Developer Edition, does Microsoft guarantee it will run on Enterprise.  I realize of course that 99.9% of the time it will, but is it a safe and best practice?  Licensing: The developer edition is significantly lower priced; I think Premium MSDN includes the rights to run the Enterprise edition non-Prod environments. If QA accesses a file on a QA server, which license do they need?  Clustering: Further, we run clustered environment in production.  I've rarely been anywhere that we have clustering in QA or even STAGE.

This is a  about Licensing.    Questions on licensing are off-topic on Server Fault.  If your question has been closed as a duplicate of this question, then this is because we want to help you understand why licence questions are off topic rather than just telling you "it just is". In all likelihood, this question will not address your question directly, it was not meant to.    I have a question regarding software licensing. Can the Server Fault community please help with the following:   How many licenses do I need? Is this licensing configuration valid? What CALs do I need to be properly licensed? Can I run this product in a virtual environment? Can I downgrade this product to an earlier version? Am I entitled to feature X with license Y?


I have been trying to pull specific values from the "on-ice" chart and applying this to many players at once but I cannot seem to string together the correct path to achieve this. Here is the link to the page:  For example if I want the CF from the 19-20 season. I've been using variations of this formula to achieve it but never have a result. =IMPORTXML("https://www.naturalstattrick.com/playerreport.php?fromseason=20192020&thruseason=20192020&playerid=8465009&sit=5v5&stype=2","/table/tr[10]/td[2]")

Google Sheets has several import functions   IMPORTDATA IMPORTFEED IMPORTHTML IMPORTXML   Sometimes the above functions returns errors like #N/A Imported content is empty and would like to be sure that there isn't a problem with the resource content to be imported.  How do I know if these functions are able to get the content that I looking to import?  I know that there also exist IMPORTRANGE but that function only is able to import content from Google Sheets spreadsheets


I'm trying to solve the following integral:  $$\int_{-\infty}^{\infty} \frac{x\sin(kx)}{x^2+a^2} \,\mathrm{d}x$$  I don't really have any idea where to start. The previous parts of the question involved complex numbers and Cauchy's Integral Formula, however I can't  think how I'd applying that here.  Any help would be greatly appreciated :)

Calculate the integral$$ \int_0^\infty \frac{x \sin rx }{a^2+x^2} dx=\frac{1}{2}\int_{-\infty}^\infty \frac{x \sin rx }{a^2+x^2} dx,\quad a,r \in \mathbb{R}. $$  Edit: I was able to solve the integral using complex analysis, and now I want to try and solve it using only real analysis techniques.


I'm writing a GLFW library wrapper - class named GLFW_Facade. There is RenderLoop function which is mentioned to be a loop in which a rendering function will be executed. I need to pass that rendering function to the RenderLoop. I would like that rendering function can take varying amount of parameters so I made that with template. Code compiles but isn't linking.  At first I was passing a std::function with varying amount of arguments,  like so   template <typename... N> void GLFW_Facade::RenderLoop(std::function<void, N...>& cb, N... params)   then I've created a class-wrapper for std::function with varying arguments named Functor.  template <typename R, typename... Args> class Functor { public:     typedef std::function<R(Args...)> FuncType;     Functor(FuncType func) : mFunc(func) {}     Functor& operator()(Args... args) {         mFunc(args...);         return *this;     } private:     FuncType mFunc; };  template <typename... N> void GLFW_Facade::RenderLoop(Functor<void, N...>& cb, N... params) {     CheckGLFWWindow();     while (!glfwWindowShouldClose(m_Window)) {         cb(params);         ProcessCloseCondition();         glfwSwapBuffers(m_Window);         glfwPollEvents();     } }  ///usage  Functor<void, int> renderfn(render); glfw->RenderLoop<int>(renderfn, VAO);   Error LNK2019   reference to a not allowed external symbol "public: void __cdecl GLFW_Facade::RenderLoop(class Functor &,int)" (??$RenderLoop@H@GLFW_Facade@@QEAAXAEAV?$Functor@XH@@H@Z) at function main    .../main.obj    1     I was expecting that will be linked out.

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


How are Animagi’s animals related to the wizards themselves? I mean, if there’s someone who is really brave, will their Animagus form be a lion (since this is the stereotyped vision of brave) or could they become a very brave beetle? does the magic also incorporate like height, weight, age?

Say that I want to become an Animagus, and am really hoping to be a certain animal (say, a stag). I study a whole bunch and manage to perfect the technique. Do I get to pick the animal I wind up as, so that I wind up being a stag like I want? Or is it something where I just find out what I turn into (and if I wind up as a dung beetle, tough luck)?    This is not a duplicate of  because that question is about which animals an Animagus can potentially transform into. Mine is about if I can decide which potential animal I wind up being.


If I have a java float and I want to increment/decrement it by the minumim possible value how can I determine that value? I mean it is a difference if the value of the float is already a very large number like 3.4028235E38 or a very small number like 1.4E-45. In the first case to note any difference I need to subtract a far lager number as I would need to add to the second case right?

I have a double value f and would like a way to nudge it very slightly larger (or smaller) to get a new value that will be as close as possible to the original but still strictly greater than (or less than) the original.  It doesn't have to be close down to the last bit—it's more important that whatever change I make is guaranteed to produce a different value and not round back to the original.