Is the law of the equality of inertial and gravitational mass valid in all possible cases?

I have been thinking about equivalence principle (EP) for a while and I am intrigued about the following.  A classical example to explain EP:    On the one hand, imagine we have an elevator (e_1) located in space and it is uniformly accelerated (a) with someone inside.  On the other hand, imagine we have an elevator (e_2) located in the surface of the earth and it is subjected to earth's gravity (g).   It is accepted a = g, so theoretically we can not distinguish between e_1 and e_2.  But wait a second.  If we analyse e_1 we will realize the entire elevator and the person inside are uniformly accelerated equally. That is okey, what we expected.  But if we analyse e_2 the entire elevator will not be subjected to the same g! I confess it was a beautiful moment for me when I realized.  g = GMe/Re^2 As we increse elevator's height, g dicreases. Doing some research, I learnt this phenomena is called tidal force.  So if I am not wrong, I guess the law of the equality of inertial and gravitational mass is not valid in all cases. We could only accept it when elevator (in this example) is small enough (g will not suffer a significant change).  Could we avoid tidal force rotating e_2?


Suppose $a$, $b$, and $c$ are integers. Prove that if $a \mid b$ and $a \mid c$, then $a \mid (b +c)$


I need to suggest a tool to build a map together, ie. let multiple users add POIs and routes on a map.  I know about OSM-based  but are there other online tools I should know about?


Weird box that I can't get rid of on the viewport

When I made alt b this red box outliner showed up and no matter what I do I couldn't get rid of what should I do. I restarted blender and nothing has changed.


To reopen a closed question,  must agree that the question is suitable for the site and cast votes to reopen the question. But:  How does one actually vote to reopen? Is there a reputation level that you must have before you can see this function? Or do I just leave a comment along the lines of, "I vote to reopen"? What happens if someone with less than 3000 reputation leaves a comment that they wish to vote to reopen? How can one draw attention to their closed questions? Is it done via a posting new question? Or do you edit the closed question?   Related:  For more information, see "" in the .


Badges oversized and cut off on mobile site

I have no idea if it's just a local problem, but I don't remember changing any settings recently.  I am seeing a few bugs on the mobile version of the site, but the one I've seen consistently over the past few days is badges rendering too big for their container.   Here is an example screenshot:    I'm using a nexus 5. I searched for similar bug reports here to no avail before posting this.  Can anyone confirm that it's reproducible?  Can anyone explain why it's happening?


Unable to install "": snap "" has "install-snap" change in progress

I just finished the installation of the Ubuntu 18.04, but whenever I try to install any application from Ubuntu Software the same error occurs (for example "vlc"):     unable to install "vlc": snap "vlc" has "install-snap" change in progress   I hope somebody can tell me what I've done wrong.


What do all the pictures on the front of the "Unix and Linux System Administration Handbook" represent?

I'm a newcomer to Unix and Linux, and I've been trying to get up to speed on everything. One of the guides I've used is the "Unix and Linux System Administration Handbook"  It's a pretty great book, and I'm enjoying reading through it, but I'm really confused by all the things that are on the cover. While this may not be a typical question for Unix & Linux Stack Exchange, I don't think it is necessarily a bad question so I'm going to go out on a limb and ask:  What do all the crazy things on the cover of this book represent?   Attached is an image of the book and a reference key. Thanks for the history lesson.     Flag Flag (Finland's for Linus Torvalds?) Bird / Cake Guy in a lab coat with a baseball bat Gnome Clam Python Cowboy and two cats Penguin Gorilla Old dude on another boat sailing away and apparently flipping off this boat Two guys carved in wood with a shield Octopus / Monster Filing cabinet Clock Indian Girl with a book Computer using a canon Window frame Lady, fishing pole, and boot Apple Core Less and More Bar of Soap / Can of Spam Periscope Heart / Valentine Monster with Maracas   ps: What is the significance of the ship?


Supervised learning with uncertain data?

Is there an existing methodology for applying a supervised learning model to a uncertain dataset? For example, say we have a dataset with classes A and B:  +----------+----------+-------+-----------+ | FeatureA | FeatureB | Label | Certainty | +----------+----------+-------+-----------+ |        2 |        3 | A     | 50%       | |        3 |        1 | B     | 80%       | |        1 |        1 | A     | 100%      | +----------+----------+-------+-----------+   How could we train a machine learning model on this? Thanks.


Is the zero set of a real polynomial union of smooth manifolds?

Question: If I have a non-zero polynomial $P(x_1,\ldots,x_n)$ defined on $\mathbb R^n$, is it true that the zero set $$Z(P) = \{x \in \mathbb R^n: P(x_1,\ldots,x_n) = 0\}$$ can be written as finite union of smooth submanifolds of $\mathbb R^n$?  This is probably a very basic thing of real algebraic geometry, but I'm totally ignorant in the area. If the response is affirmative, can anyone provide a reference?


What is the highest melting temperature of chocolate?

A pure chocolate bar will always melt at 33 Celsius, as several of my books assure me.   But an answer to another question .   What kind of chocolate can do this? What does it contain? How much actual chocolate would be inside it, and what is the rest made of? What is the highest melting temperature which can be achieved by such a product? What would be some generic terms for it - if I wanted some and went to a chocolate shop, what would I have to ask for?


Tomcat 7 is being unresponsive when I turn on SSL (no SSL handshake)

My question is: why won't tomcat respond when I turn on SSL?  I've attempted to migrate a working tomcat7 web application from an Ubuntu 12.10 x64 Server to a fresh Ubuntu 14.04 x64 server.  Every attempt has been made to keep the configuration the same between the two machines.    Everything was working great on port 80.  When I edit the server.xml file to enable the SSL Connector, then I stop getting responses from the server.  I can open a connection but it just hangs there.  For example I can telnet to port 443, and I can send a "GET /" command, but there is no response.  The server is not attempting an SSL handshake.  There are no errors in catalina.out, in fact I can see the success message for the SSL protocol handler:  Feb 13, 2015 10:28:49 AM org.apache.coyote.AbstractProtocol init INFO: Initializing ProtocolHandler ["http-bio-443"]   I've verified that the keystore file is valid by listing the contents with the keytool command.  The keystore is just a copy of the one from the old server so I don't expect any problems with the certificates or anything.  The file permissions on the keystore should not be a problem, I've even tried chmod 777 on it and there is no change in behavior.  Here is my Connector for server.xml.  Again server.xml is an exact copy from the previous Ubuntu 12 server so I think the issue lies somewhere else.  <Connector port="443" SSLEnabled="true" protocol="HTTP/1.1"            maxThreads="150" scheme="https" secure="true"            clientAuth="false" sslProtocol="TLS"            keystoreFile="/var/lib/mywebapp/mywebapp.keystore"            keystorePass="xxxxxxxx"/>    I've tried to explicitely set the protocol here and i've tried all three values available:  org.apache.coyote.http11.Http11Protocol - same result  org.apache.coyote.http11.Http11NioProtocol - same result  org.apache.coyote.http11.Http11AprProtocol - exception that APR/native library is not available  tomcat version info:  Using CATALINA_BASE:   /usr/share/tomcat7 Using CATALINA_HOME:   /usr/share/tomcat7 Using CATALINA_TMPDIR: /usr/share/tomcat7/temp Using JRE_HOME:        /usr Using CLASSPATH:       /usr/share/tomcat7/bin/bootstrap.jar:/usr/share/tomcat7/bin/tomcat-juli.jar Server version: Apache Tomcat/7.0.52 (Ubuntu) Server built:   Jul 24 2014 08:38:51 Server number:  7.0.52.0 OS Name:        Linux OS Version:     3.13.0-37-generic Architecture:   amd64 JVM Version:    1.7.0_71-b14 JVM Vendor:     Oracle Corporation


An MO answer by Terry Tao regarding what the Laplacian measures

In his answer to an MO question: "", Terry Tao says that     The Laplacian of a function $u$ at a point $x$ measures the average extent to which the value of $u$ at $x$ deviates from the value of $u$ at nearby points to $x$ (cf. the mean value theorem for harmonic functions).    Would anybody elaborate (probably with examples) how the mean value theorem for harmonic functions relates to the point he makes about the Laplacian?


What does the tilde before a function name mean in C#?

I am looking at some code and it has this statement:    ~ConnectionManager() {     Dispose(false); }   The class implements the IDisposable interface, but I do not know if that is part of that the tilde(~) is used for.


Evaluate  $\displaystyle\sum_{n=1}^{50}n \!\cdot\! n!$  I tried to write the sum like: $1+2\!\cdot\!2!+3\!\cdot\!3!+4\!\cdot\!4!+5\!\cdot\!5!+\ldots=1+4+18+96+600\ldots$  I can find a recursion like $t_{n+1}=t_n(n+2)+n!$ where $t_n=n\!\cdot\!n!$, so:  $1\!\cdot\!3+1=4$  $4\!\cdot\!4+(1\!\cdot\!2)=18$  $18\!\cdot\!5+(1\!\cdot\!2\!\cdot\!3)=96$  $96\!\cdot\!6+(1\!\cdot\!2\!\cdot\!3\!\cdot\!4)=600$  But I'm not sure how to proceed further or if this is the way to do it. Any help is appreciated.


What is the mathematical relationship between R2 and MSE?

Trying to understand this relationship I came across this conversation in an email group:           I got a problem while analyzing my data using NN.      I got R-square with 0.45 with MSE around 5000.     SO I am wonder why? There must be a relation     between R-square and MSE?         R2 = 1 - SSE/SS0      SSE = N*MSE SS0 = (N-1)*VAR(Target)      VAR(T) = SS0/(N-1) = [SSE/(1-R2)]/(N-1)      = [N/N-1]*MSE/(1-R2)      ~ 5000/0.55 ~ 9091      If you had standardized your targets to unit variance you would have   obtained MSE ~ 0.55   Is that correct? What insights can we reach understanding this relationship?


Can I exchange limit and differentiation for a sequence of smooth functions?

Let $(f_n)_{n\in \mathbb N}$ be a sequence of smooth functions converging to some $f$.  Under what circumstances can I exchange limit and derivative?, i.e.  $$\lim_{n\rightarrow \infty} \frac{\partial f_n(x)}{\partial x} = \frac{\partial f(x)}{\partial x}$$


How to use \ContinuedFloat with figure side by side together?

I want to plot a subfigure side by side using \ContinuedFloat as shown below:  However, I always get below:  \documentclass{article} \usepackage{graphicx} \usepackage{caption} \usepackage{subcaption}  %---------------- show page layout. don't use in a real document! \usepackage{showframe} \renewcommand\ShowFrameLinethickness{0.15pt} \renewcommand*\ShowFrameColor{\color{red}} %---------------------------------------------------------------% \usepackage{lipsum}  \begin{document}  \begin{figure}[hb!]     \centering     \begin{subfigure}{0.6\textwidth}         \includegraphics[width=\textwidth]{example-image}         \subcaption{$Q^{*}$ values for arm 1}         \label{fig:arm1}     \end{subfigure}      \begin{subfigure}{0.6\textwidth}         \includegraphics[width=\textwidth]{example-image}         \subcaption{$Q^{*}$ values for arm 2}         \label{fig:arm2}     \end{subfigure}      \begin{subfigure}{0.6\textwidth}         \includegraphics[width=\textwidth]{example-image}         \subcaption{$Q^{*}$ values for arm 3}         \label{fig:arm2}     \end{subfigure}     \caption{$Q^{*}$ values for different arms} \end{figure}%  \begin{figure}[ht]\ContinuedFloat     \centering     \begin{subfigure}{0.45\textwidth}         \includegraphics[width=0.9\textwidth]{example-image-a} %         \subcaption{$Q^{*}$ values for arm 4}         \label{fig:arm3}     \end{subfigure}      \begin{subfigure}{0.45\textwidth}         \includegraphics[width=0.9\textwidth]{example-image-b} %         \subcaption{$Q^{*}$ values for arm 5}         \label{fig:arm4}     \end{subfigure}     \caption{$Q^{*}$ values for different arms (cont.)}     \label{fig:arms} \end{figure}       \begin{figure}     \centering     \begin{minipage}{0.45\textwidth}         \centering         \includegraphics[width=0.9\textwidth]{example-image-a} % first figure itself         \caption{first figure}     \end{minipage}\hfill     \begin{minipage}{0.45\textwidth}         \centering         \includegraphics[width=0.9\textwidth]{example-image-b} % second figure itself         \caption{second figure}     \end{minipage} \end{figure}           \end{document}


Bounty questions should have a grace period to accept an answer after 7 days

I feel that there should be a period of time after a bounty expires before it is automatically assigned. This way, each bountied question can have its full 7-day timespan for meaningful answers to be added, and no bounty offerer will have to cut a bounty period short or risk missing out on being able to assign a bounty.  A period of 12-72 hours would be more than sufficient IMO.


As you can see, there's these weird planes stretching down :(. Does anyone know what causes this, & how I can fix it?


which version for my netbook acer v5=121

2gb RAM 500 gb HDD AMD C- 70, 1 GHz wireless, touch pad functions which version is better


Number Theory proof involving the sum of Legendre symbols

If $b$ is a unit mod $p$, show that $(\frac{b}{p})+(\frac{2b}{p})+\cdot \cdot \cdot +(\frac{(p-1)b}{p})\equiv 0$.  Since $b\in U_p$ then $(\frac{1}{p})+(\frac{2}{p})+\cdot \cdot \cdot +(\frac{(p-1)}{p})$.  (So I'm not sure if I'm stating this part correctly) Therefore for each $(\frac{i}{p})$ for $i=1,...,p-1$, $i$ is either in $Q_p$ or not. Since $|Q_p|=\frac{\phi(p)}{2}=\frac{p-1}{2}$. Half will be in $Q_ p$ and the other half will not. So we get $(\frac{1}{p})+(\frac{2}{p})+\cdot \cdot \cdot +(\frac{(p-1)}{p})=1-1+1-\cdot\cdot\cdot +1\equiv0$.  Is this okay?


Problem with footnote placement in beamer

I am using the beamer class for my presentation. My problem is the placements of footnotes. Unfortunately, all footnotes appear at the end (the last slide of the presentation). How do I get footnotes to appear on the slide I used them? \documentclass{beamer} \begin{document} \begin{frame}[allowframebreaks]{} This is\footnote{The first Footnote} a test.\\ This is\footnote{The second Footnote} a test.\\ This is a test.\\ This is a test.\\ \framebreak This is a test.\\ \framebreak This is\footnote{The first Footnote} a test.\\ \end{frame} \end{document}


Apt-get does not complete after fetching sources

I upgraded to 16.04 from 15.10 today.  Now I can no longer perform software updates. Running sudo apt-get update results in the following:  Hit:1 http://archive.ubuntu.com/ubuntu xenial InRelease Get:2 http://security.ubuntu.com/ubuntu xenial-security InRelease [94.5 kB] Hit:3 http://archive.canonical.com/ubuntu xenial InRelease                      Hit:4 http://archive.ubuntu.com/ubuntu xenial-updates InRelease                 Hit:5 http://archive.ubuntu.com/ubuntu xenial-backports InRelease               Fetched 94.5 kB in 1s (83.7 kB/s)     and it just sits there.  I left it like this for 4 hours.  Top shows that after running the command, appstreamcli goes to 100% cpu and stays there.  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND                                        6741 root     20   0  120556  37456   9340 R  99.7  0.5   1:22.71 appstreamcli       Looks like I may not be the only one experiencing this...


How to map each point hypercube to a simplex that contains the point and shares all edges with the hypercube?

I'm trying to find a mapping from a point in a unit $n$ dimensional hypercube* a $n$-simplex that contains the given point and which shares all corners with the unit hypercube. Define the hypercube as $H=(0,1)^n$ and the corners of the hypercube as $C=\{0,1\}^n$ Is there a function $f:H \mapsto C^{n+1}$ so that the tuple $f(p)$ defines the corners of a simplex that contains the point $p \in H$? There are probably many such functions, but any one would suffice. Further, is it possible to construct $f$ in such a way that all the different $n$-simplices in the image of the function do not overlap?


If $\frac{f(x)}{x}$ is decreasing in $(0,\infty)$, prove that $f(a+b) \leq f(a) + f(b)$ for $a,b >0$


I am flying BA from Dublin to LHR then Qatar Airlines from LHR to Doha and Kilimanjaro.  Will I be able to check my luggage through from Dublin to Kilimanjaro?


What is the cause of the surface tension of the liquids? How to know the direction of tension force on the free surface of the liquid?   I know that the surface tension is the force acting normally per unit length of the imaginary line drawn on the free surface of a liquid, but don't have any idea about the cause of the surface tension. More over I don't know the direction of the tension force i.e. where it towards liquid or away from the liquid.  Any idea or help will be greatly appreciated!


which regression to use when response variable is in percentage


This question was marked as duplicate of . I am not asking how to create enumerations, I'm asking how to create constants, and that is the difference between the questions.  This question was marked as duplicate of . While the answers do explain how to create constants in python they don't explain how to create them in Enum like style, which is what my question is asking for.  I need to create constants in my python code. I don't want the user to be able to modify them. I found , but it is not exactly what I need. I need to be be able to use them just like enums, without creating and instance.  For example:  class MyConstClass(object):     Const0 = 0     Const1 = 1     Const2 = 2  myfunc(MyConstClass.Const0) MyConstClass.Const1 = 20 # Raise an exception   I also don't want to create a module, just like it is done   Is there a way to do it?


I'm trying to check a string for a specific number but it doesn't seem to find it.  string = sc.next();  if(string != "-1")  return 0;   So when I enter -1 into the input, it just continues on without breaking the program. Am I doing something wrong here?


Join multiple rows into one using for xml path

I have the following sql:  select distinct a1.Id, a1.Value from #table1 a1 where a1.Id in (select a2.Id from #table1 a2 join #table1 a3 on a2.Id = a3.Id  where a2.Value <> a3.Value)   It groups the same Ids from the same table, in case their respective values are different. Example output:  | Id |Value| | 1  |  1  | | 1  |  3  | | 1  |  2  |  | 2  |  4  |  | 2  |  5  |   I want to concatenate this rows into one so it looks like this:  | Id | Value |  | 1  | 1,3,2 | | 2  | 4,5   |   I tried using for xml path, but I can't figure out how to do it correctly:   select a1.Id,  SUBSTRING( ( SELECT ',' + CAST(a1.Value as varchar(50)) [text()] where a1.Id in     (select a2.Id from #table1 a2     join #table1 a3 on a2.Id= a3.Id     where a2.Value<> a3.Value     )  FOR XML PATH ('')  ), 2, 1000) [Value] FROM #table a1   But it is not working. I am using Microsoft SQL. I have a problem of transforming 'in sub-query' into valid sql where I could use 'FOR XML PATH('')'. I tried using cross apply, but I can't figure out how to correctly join 3 times the same table


SELECT records as comma separated string

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.


What can the eigenvalues of unitary matrices tell us?

I'm searching for applications where the distribution of the eigenvalues of a unitary matrix are important. Example properties of the eigenvalues could be that the eigenvalues are clustered, that they live in some half plane, that, in the case that the matrix has real eigenvalues, that a certain fraction are 1, etc. Are there any well known areas where this is important?


added lines to /etc/apt/source.list that cannot be read

I'm trying to install an SDL library found here (). Per the instructions on the website I added two lines to my sources (/etc/apt/sources.list), but linux says that it cannot read the added lines that begin with 'rpm'. How do I install this library?  My terminal simply says E: type 'rpm' is not known on line 52 in source list /etc/apt/sources.list


Using a multimeter and set it on 200V DC - that's the lowest on this meter. Tested a 1.5V and it reads 2.8 Tested a 3V and it reads 6. Just replaced the battery. The meter is ETEKCITY. Any suggestions?


I stupidly ran this command in Ubuntu 18.04:  sudo chown -R $USER:$USER /usr   Now I want to undo this but when I run:  chown -R root:root /usr   I get this error:  operation not permitted   And I can't run a sudo command and gives me this error:  /usr/bin/sudo must be owned by uid 0 and setuid bit set   How can I fix this?


Pathfinder Natural Weapon Damage by Size Inconsistency

Source:   Take for example a bite attack. According to the table, a small bite does 1d4 damage, medium 1d6, large 1d8, huge 2d6, garg. 2d8, and col. 4d6. Presumably it'd continue 4d8, 8d6, etc.  However, if you look at the FAQ entry right below it, it says that as you increase the damage, the progression would be 1d4, 1d6, 1d8, 2d6, 3d6, 4d6, 6d6, 8d6, 12d6, etc.  So what is this supposed to mean? Does it mean for example that a gargantuan entity would do 2d8 damage with a bite attack, but a huge one enlarged to gargantuan would do 3d6?  This seems it might be a duplicate of  That question is 2 years old. Have we gotten any new information since then? Also, the newer chart is listed as a FAQ instead of an errata, which implies that the old chart might not be a mistake?


I am writing a simple Python for loop to prnt the current character in a string. However, I could not get the index of the character. Here is what I have, does anyone know a good way to get the current index of the character in the loop?   loopme = 'THIS IS A VERY LONG STRING WITH MANY MANY WORDS!'   for w  in loopme:     print "CURRENT WORD IS " + w + " AT CHARACTER "


is the expansion of the universe observable at a smaller scale?

I have searched the network for a possible duplicate to this question but I have not found one particulary answering my question so recommendations are welcome.  I understand that distances of celestial bodies from earth can be estimated by using knowledge of nuclear  fussion, the doppler effect and spectral colors of wavelengths visible to humans (red and blue shift).   Knowledge of the distances, speeds and frequencies of wave emmisons from distant galaxies have led to the general assumption that the universe is expanding.  What is evidence of the universe expanding on a smaller scale like solar systems and even planetary behaviour if any


I used to run minecraft servers in 14.04 by either clicking the .sh file, and selecting run in terminal, or running the .jar file. I'm on 18.04 now, and I can't run the .sh file at all. Double clicking immediately opens up text editor, and dragging it to a terminal also opens the text editor. Trying to open the server.jar gives me a small window for half a second, which immediately closes. Has something changed, and does anyone know how to run .sh files now?


Does a force propagate instantaneously to move the other side of the box of length one light-year?

This is a question of curiosity, and not for any academic purposes.  Suppose I push a box along a surface that allows it to slide. When I initially start pushing it on one side, how long does it take for the other side of the box to start moving?  Obviously, it's going to be observed as instantaneous, but in the extreme case of a 1 lightyear-long box, I find it hard to believe that all of it would start moving at the exact same time.


How can I install without a USB or CD? I have tried UNetbootin and wubi

I need help pretty major! I have tried UNetbootin and Wubi To intsall Ubuntu 14.10, neither worked, I have an HP 2000 and am running Windows 7 Ultimate (My computer came pre-installed with Windows 8... Its a long story) anyway! I need help! Please!!!   Edit: I don't have a DVD Rom or a USB Stick, so i need to install it without those, Wubi from what I understand is supposed to have an option to install like an application in windows, im not sure if this was removed with an update or anything. Also when I use wubi it attempts to download another .ISO for Ubuntu when the one I have is perfectly fine and all the files are intact. Untebootin just does not work for me for some reason.  Edit: Thank everyone for their help!! But i got it installed! Yayyyyy


Before wordpress.stackexchange.com/ was created, a lot of WordPress questions were asked on SO. Are these going to be migrated, or are they going to stay in SO?     A good example is this question:         Also, if a question is migrated to another site, what happens to the reputation gained from it?


I know:   Single Double Triple Quadruple   But what comes next? Up to 10 would be fine.


how to round off float after two place decimal in c or c++

how to round off float value after two place decimal in c or c++  examples:    let input is 95.346789 so output is 95.35   let input 95.345 output is 95.35  let input 95.344 output is 95.34


URLFOR Action to New Object for specific recordtype

I have a custom object that has various record types. How would I construct URLFOR statement to take me to the new action for a particular record type?  URLFOR($Action.Relationship_Detail__c.New)  The RecordType I want to go to is called AccountAccountRelationship in the Record Type Name field  Also I feel like I should mention that this is part of an outputLink and the value is being set to this URLFOR


What's a word that means both 'source' and 'sink'?

In the sense of: it can emit data but it can also receive data. Or water. Or gas. Or whatever.


I would like to search for answers to a problem related to a code issue in PHP with Class::method.  While I was searching for answers I realised Google seems to drop the :: in all search queries.  The answers are all without the double colons. Even single colons will get dropped for the searches.  How can I search for double colons in google?


As Parker repeatedly asks after they bring the face-hugged Kane aboard, why don't they freeze him? I understand that Ash doesn't want to, but neither Dallas nor any other crew member provide any reason for not putting Kane in cryo and dealing with him later.


Here is a simple document:   \documentclass{article} \usepackage[%   backend      = biber,   bibstyle     = biblatex-sp-unified, ]{biblatex} \addbibresource{test.bib} \begin{document}  \cite{test}  \printbibliography{} \end{document}   Which refers to  and this simple bib file:  @article{test,   Author = {test},   Title = {test} }   This used to work. After updating my MacTeX distribution this Sunday morning and (full disclosure) doing a sudo tlmgr update --all, I now receive errors like the following:   ! Undefined control sequence. <argument> \bbl@main@language  l.12 \printbibliography{                         } ?   Curiously, if either the Author or Title field is missing, I don't get an error. Moreover, if I remove the bibstyle option, the error goes away. This leads me to suspect that the problem is somewhere in the bbx file linked above, but that's as far as my limited knowledge and expertise gets me.   I realize this might be a rather specific question (and I have opened an issue on the github I linked to), but perhaps there is a general issue causing the problem here, in which case others might benefit from a general solution.


With 8 bits is it possible to obtain an integer in more than one way?

This is just a curiosity that just came to my mind while thinking at IP addresses. A byte is composed of 8 bits. A bit can either be $0$ or $1$. IPv4 addresses are composed of a group of 4 bytes. These bytes are usually represented in decimal dot notation (because it's easier for humans), but sometimes I need to figure out in my head the binary numbers. So, if I know that there's just one configuration, and if my calculations are correct, then I am sure that my solution is correct.  My question is, is possible to obtain a certain integer $k$ using more than one combination of the $8$ bits? For example, suppose we want to represent in binary the number $123$. Is it possible to represent it in 2 or more different configurations of the 8 bits? What about if we have more than $8$ bits?  This might seem a silly question, but a proof might satisfy me.


GCDs in integral domains are unique up to unit factors (associates)

The book I am reading mentioned that the greatest common divisor of $a_1, \cdots a_n$ in an integral domain $R$, whenever it exists, is unique up to arbitrary invertible factors. What does "up to arbitrary invertible factors" mean?  Definition: Let $a_1, \cdots, a_n$ be nonzero elements of the ring $R$. An element $d \in R$ is a greates comon divisor of $a_1, \cdots a_n$ if it possesses the properties:   $d \vert a_i$, for $i=1, c\dots n$ $c \vert a_i$, for $i=1, \cdots n$ implies $c \vert d$.


gives the following definitions:      Right censoring: a data point is above a certain value but it is unknown by how much.    Left censoring: a data point is below a certain value but it is unknown by how much.   In these definitions, what is meant by:   "data point" "certain value", and "how much"   In general, What is right and left censoring?  Is the statement below true :     "In Right censoring, we only have the lower bound for censored value."    What would be the analogous statement for left censoring?


How to correctly load saved SharedPreferences from another activity on startup?

I thought the error I'm catching is for only the first time running (where there's still no SharedPreferences saved, but the error pops up everytime I run the app (in MainActivity): Attempt to invoke virtual method 'int com.android.test.helper.PreferencesHelper.load(java.lang.String)' on a null object reference   The same function however works and loads the value under that key (key_foo) successfully in the OptionsActivity where that option is saved. MainActivity runs first when opening the app immediately being replaced by OptionsActivity after some more setup. MainActivity.java: public class MainActivity {     private PreferencesHelper preferencesHelper;      @Override     protected void onCreate(Bundle savedInstanceState){         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);                  try {             preferencesHelper.load("key_foo");             recreate();         }         catch(Exception e) {             Log.d("ERROR", e.getMessage());         }         startOptionsActivity();     } }  PreferencesHelper.java: public class PreferencesHelper {     private Activity context;     private SharedPreferences sharedPref;     private SharedPreferences.Editor editor;      public PreferencesHelper (Activity activity){         context = activity;         sharedPref = context.getSharedPreferences("file", 0);     }     public int load(String key){         sharedPref = context.getSharedPreferences("file", 0);         return sharedPref.getInt(key, -1);     }     public void save(String key, int value){         editor = sharedPref.edit();         editor = putInt(key, value);         editor.apply();     } }  OptionsActivity.java: public class OptionsActivity {     private PreferencesHelper preferencesHelper;      @Override     protected void onCreate(Bundle savedInstanceState){         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_options);                  preferencesHelper.save("key_foo", 42);         recreate();          try {             preferencesHelper.load("key_foo");         }         catch(Exception e) {             Log.d("ERROR", e.getMessage());         }     } }


What happens when a creature with "Whenever a creature dies" dies simultaneously with multiple other creatures?

has the following ability:     Whenever a creature you control with a +1/+1 counter on it dies, return that card to the battlefield under your control at the beginning of the next end step.   I had a number of creatures on the battlefield, including Marchesa herself, with one or more +1/+1 counters on them when  was played, destroying each creature on the board.  When Marchesa and several other creatures would be killed simultaneously,   Does Marchesa's ability trigger for herself? Does Marchesa's ability trigger for the other creatures under my control with +1/+1 counters?   In attempting to resolve the issue, we tried to look things up, leading to , which cites Rule 603.6d as proving that Marchesa's ability should trigger both for herself and for each other creature with +1/+1 counters.  Unfortunately, none of us could actually understand Rule 603.6d, aside from this example:     Two creatures are on the battlefield along with an artifact that has the ability Whenever a creature dies, you gain 1 life. Someone plays a spell that destroys all artifacts, creatures, and enchantments. The artifacts ability triggers twice, even though the artifact goes to its owners graveyard at the same time as the creatures.   The example certainly seems analogous to me, but without understanding the actual rule, rather than just the example, we weren't too sure.  A complete answer has to not only answer the question, but back up that answer with citation and explanation of the official rules on the matter.


I have a transcend 250GB hard drive which recently stopped working. It didn't sustain and physical damage that I am aware of, dropping, water ect... It won't even pop on the desktop, and isn't recognized with disk manager. I plugged it into a mac to test it and the exact same thing happened. I has using it an hour before, i turned the computer off and when i returned I booted the system to find the HDD clicking.  I heard this could be caused by the reader not finding the center point so it can't read any data also I heard this could be caused by the HDD not receiving enough power form the computer but I doubt this is the problem  My question is there any thing you guys know that will allow be to access the data once to  extract the data off it without using a service?


How do I prove that the product of two closed sets is closed?

Given $A \in \mathbb{R^q}$ and  $B \in \mathbb{R^p}$ two closed sets, then $A \times B$ is a closed set in $\mathbb{R^m} = \mathbb{R^q} \times \mathbb{R^p}$  How do I prove the previous result by using sequences?


Free particle Schrodinger equation: propagator

I am going through Shankar's Principles of Quantum Mechanics and am having trouble finding the free particle propagator $U(t)$ that satisfies $$\lvert\psi (t)\rangle = U(t)\lvert\psi (0)\rangle$$ due to the degeneracy of the $E$ eigenkets. Shankar says that if the Hamiltonian has degenerate eigenvalues, we change the propagator equation from $$U(t) = \sum_{E} \lvert E\rangle\langle E\rvert e^{-iEt/{\hbar}}\tag{4.3.13}$$ to $$U(t) = \sum_{E} \sum_\alpha \lvert E, \alpha\rangle\langle E, \alpha\rvert e^{-iEt/\hbar} $$ where $\lvert E, \alpha \rangle $ are the orthonormal eigenkets for the $E$ eigenspace. This makes sense to me, because it seems like whenever we deal with degeneracy to use a projection. He also says for a Hamiltonian with no degeneracy to change the sum into an integral, so I imagine that for a Hamiltonian with a continuous, degenerate spectrum we would have this propagator: $$ U(t) = \sum_\alpha\int_\Re dE\lvert E, \alpha\rangle\langle E, \alpha\rvert e^{-iEt/\hbar}$$  I tried applying this to the free particle and had some trouble. In the book, after solving for the eigenkets and eigenvalues, $\lvert E\rangle = \lvert p\rangle$ and $p = \pm\sqrt{2mE}$, he chooses the propagator as a function of the momentum eigenvalues $p$ so that $$U(t) = \int_\Re dp\lvert p\rangle\langle p\rvert \exp(-ip^2t/2m).\tag{5.1.9}$$ I understand how he got to this, but I'm having some trouble because this doesn't appear to be the same expression that I have above. Splitting the integral up, we have $$U(t) = \int_{-\infty}^0dp\lvert p\rangle\langle p\rvert \exp(-ip^2t/2m) + \int_0^\infty dp\lvert p\rangle\langle p\rvert \exp(-ip^2t/2m)$$ The left integral can changed to an integral over $-p$, and the bounds switch from $0$ to $\infty$ such that: $$U(t) =  \int_{0}^\infty d(-p)\lvert -p\rangle\langle -p\rvert \exp(-ip^2t/2m) + \int_0^\infty dp\lvert p\rangle\langle p\rvert \exp(-ip^2t/2m)$$ Now we can substitute and interchange $\lvert p\rangle = \lvert E, + \rangle$,  $\lvert -p\rangle = \lvert E, - \rangle$, $E = p^2/2m$, and $dp = \pm mdE/\sqrt{2mE}$ to get: $$U(t) = \sum_{\alpha = \pm} \int_0^\infty dEm/\sqrt{2mE}\lvert E, \alpha\rangle\langle E, \alpha\rvert e^{-iEt/\hbar}. $$ This is the result that we are asked to prove in Exercise 5.1.1. Why is this not the same as the first expression for the propagator? Where did the extra $ m/\sqrt{2mE} $ come from? Am I just wrong in assuming that that is the general expression for a Hamiltonian with continuous and degenerate eigenvalues?


How likely is it to get into grad school with many W's and an F on your transcript given you have medical documents that give reason for your grades?

I currently have a 3.47 GPA at Georgia Tech in Computer Science. I have already withdrew from 6 classes but 4 of those were from a semester I got hospitalized. I'm failing a class right now but I may be able to pull of a C or even an A because the final replaces the course grade.   I want to do a Master's in environmental science or environmental modeling. I want to be a data scientist for the NOAA or any organization working on the acidification of the ocean.   I may even do a PhD if I can. I have research experience.


Ascoli-Arzela theorem: Hausdorff assumption needed?

Theorem 4.43 is Folland's Real Analysis is     Arzelà-Ascoli Theorem I. Let $X$ be a compact Hausdorff space. If $\mathscr{F}$ is an equicontinuous, pointwise bounded subset of   $C(X)$, then $\mathscr{F}$ is totally bounded in the uniform metric,   and the closure of $\mathscr{F}$ in $C(X)$ is compact.   I could not understand where the assumption that $X$ is Hausdorff is used in the proof. Is this assumption necessary?


Hard to exclude tags in search for new nav

Before the new nav, it was possible to use the search box to require some tags and exclude others.  Typing something like [included-tag] -[excluded-tag] would bring up results that included and excluded the respective tags.  Here's an , which was made with the search [word-request] -[phrase-request].    In the new nav, typing only tags in the search area ignores the - modifier.  So typing [master] -[slave] is somehow reinterpreted into [master] [slave] (notice the negation - is now gone).  In order to work around this, I have to include some extra non-tag search criteria.  A search like [master] -[slave] is:question  as intended.  But if you remove the is:question from the search box (or the url)  to handle the tags properly.    Please fix the new tag behavior to support the old tag-exclusion behavior without having to resort to weird workarounds.    This question is a more detailed version of this .


Can we prove $ℝ^n ∖ \{\text{straight line}\}$ and $ℝ^n ∖ \text{\{an axis\}}$ homeomorphic by proving their complements homeomorphic?

I'm trying to prove that $\mathbb R^n \setminus \{\text{straight line}\}$ is homeomorphic to $\mathbb R^n\setminus\text{\{an axis\}}$. Their complements, a straight line and an axis, are isomorphic, since the bijective map we find is just a translation from one line to the other. So I thought it could be a good idea to prove that $G\cong H \Leftrightarrow G^c\cong H^c$, but I'm not sure that this is generally true. If it is true, which map could we take to prove it? And if it is false, how should I say that $\mathbb R^n \setminus \{\text{straight line}\} \cong \mathbb R^n \setminus \{\text{axis}\}?$ Or at the very least, that $\mathbb R^n \setminus \{\text{straight line}\} \simeq \mathbb R^n \setminus \{\text{axis}\}$?.


ubuntu 16.04 LTS  When I started my computer my admin acct was gone, now there is only a guest login. Cannot change user either.  When I check user accts it only shows the guest acct.  I tried this:   guest-4xiaqd@user-HP-Pavilion-dv7-Notebook-PC:~$ adduser louise adduser: Only root may add a user or group to the system. guest-4xiaqd@user-HP-Pavilion-dv7-Notebook-PC:~$ adduser adduser: Only root may add a user or group to the system. guest-4xiaqd@user-HP-Pavilion-dv7-Notebook-PC:~$  guest-4xiaqd@user-HP-Pavilion-dv7-Notebook-PC:~$ sudo adduser louise sudo: unable to change to root gid: Operation not permitted sudo: unable to initialize policy plugin   I didnt change any settings, only logged out and turned it off.  Any answers will need to be very specific because I do not understand what I am doing.  Thanks, everyone.


Error: "Could Not Find Installable ISAM"

I've written some VBA code in an Excel workbook to retrieve data from an Access database in the same directory on a desktop.  It works fine on my machine and several other machines running Windows XP, but when we tested this on a Vista machine, we encountered the following error:     Could not find installable ISAM   I've done a bunch of searching online but can't seem to find a concrete answer.  The connection string seems to be fine, and, as I mentioned, it works on several machines.  Does anyone have any idea what could be causing this?  My connection string is as follows:  Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\ptdb\Program Tracking Database.mdb;   Thanks


There are two sets $A$ and $B$ which are bound and are not empty. Now we'll define another set as: $A + B = \{a + b | a \in A, b \in B\}.$  I need to prove that $\sup(A + B) = \sup A + \sup B.$   I don't know if the way in which I proved it is enough or is missing something. This is my proof:  I know that for every $a \in A, b \in B$: $\sup A \geq a$ and $\sup B \geq b.$  Therefore $\sup A + sup B \geq a + b.$ I'll take a $c \in A+B$ and by $A+B$ definition: $c = a + b$. Then, it is safe to say that $c = a + b \leq \sup A + \sup B$ which gives: $c \leq \sup A + \sup B.$  I know that $c \leq \sup A + \sup B$ is true for every general $c \in A+B$, so the supremum of $A + B$ is: $\sup(A + B) = \sup A + \sup B.$  Is this a way to prove it or is it not enough? Thanks.


Why does perspective always have xray on?

When I toggle x-ray in Edit mode, only the orthographic views toggle. The perspective view constantly shows xray and it is super annoying. I see face handles (the square to select them) as well as edges and vertices through the faces just as if xray was on, but it's not.  How can I turn it off so that while in Edit Mode, and with Solid display mode selected, I don't see through things as if xray mode is on? Thanks]  Left: In Edit Mode Right: In Object Mode Basically I don't want to see the edges and face handles through the faces in front of them.


Positive operator has a positive spectrum?

Let $T : \operatorname{dom}(T) \rightarrow H $ be a positive self-adjoint operator, is it then true that $\sigma(T) \subset [0,\infty)$? This is something that sounds natural and I guess that it is true. For bounded operator, this can be easily shown, but the only proof I know cannot be adapted to unbounded operator, so I was wondering if anybody here knows how to show this?


Bitwise operation on enum which is not marked by [Flags] attribute

I am comparing a variable to many enum values, but the IntelliSense is giving me this warning:    if (val == MyEnum.Value1 | MyEnum.Value2 | MyEnum.Value3){    //code }   My enum looks like this:  public enum MyEnum {     [Description("Value1")]     Value1 = 0,     [Description("Value2")]     Value2 = 1,     [Description("Value3")]     Value3 = 2, }   What is it and what should I do? Is it safe? All i want to avoid is having to write the long version of an if multi-value comparison block.


how to simulate a low-memory state when running a query

I am trying to better understand how SQL Server's execution engine behaves in a low-memory state.  Speaking in terms of memory grants, I am wondering if there is some way to force GrantedMemory to be equal to RequiredMemory.  (My guess is that there's an undocumented trace flag which will do that.  Does anyone know what it is?)


Example of a function $f$ which is nowhere continuous but $|f|$ should be continuous at all points

So I had an exam today and one of the questions were: Give an example of a function $f$ which is nowhere continuous but $|f|$ should be continuous at all points. At first I had no idea how to do it then I came up with this, even though I know it's wrong:  $$f(x)= \begin {cases} \ \sqrt{x}&\text{if }x <0\\ \sqrt{-x}\ &\text{if }x > 0\\ \end {cases}$$  Like I said I know it's wrong..but can someone give me an example of this? Thanks.


I have a simple table of of 2 columns(varchar): name    |occupation ___________________ Sandra  |Medic Julija  |Actor Marija  |Actor Martyna |Manager Aiste   |Teacher Kristina|Teacher Virg    |Teacher Jurga   |Actor Justina |Medic Mia     |Manager  I need to build a pivot table that would look something like this: Medic  | Actor | Teacher | Manager | ____________________________________ Justina| Julija| Aiste   | Martyna Sandra | Marija| Kristina| Mia  null   | Jurga | Virg    | null  I have written this code to return build the pivot: SELECT * FROM (   SELECT     [name],     [occupation]    FROM employee ) as Results PIVOT (   max([name])   FOR [occupation]   IN (     [Medic],     [Actor],     [Teacher],     [Manager]   ) ) AS PivotTable  But I get only one row as a result: Medic   |Actor  |Teacher    |Manager Sandra  Marija  Virginija   Mia  Where did I made a mistake? I also can't understand what aggregate function would be more applicable, since rows contain only text(varchar).


Given a Kähler manifold $(M,g)$ and the differential $\omega=\sqrt{-1} g_{\alpha\bar{\beta}}dz^{\alpha}\wedge dz^{\bar{\beta}}$, how to arrive the following results:  $\omega$ is closed, i.e. $d\omega=0$ iff in terms of components of $g$, $$\frac{\partial g_{\alpha\bar{\beta}}}{\partial z^{\gamma}}=\frac{\partial g_{\gamma\bar{\beta}}}{\partial z^{\alpha}}.$$  I also wonder if the following property is true in complex manifold: $dz^{i}\wedge dz^{j}=-dz^{j}\wedge dz^{i}$, $dz^{i}\wedge d\bar{z}^{j}=-d\bar{z}^{j}\wedge dz^{i}$ and $d\bar{z}^{i}\wedge d\bar{z}^{j}=-d\bar{z}^{j}\wedge d\bar{z}^{i}$. The above questions seem to be easy but it take me a lot of time without correct derivations and answers. Could someone give detailed derivations and answer to the above problems?


Find the limit of the sequence $(a_n)_{n \ge 0}$ given that $a_{n+1}^2=a_na_{n-1}$ and $a_0=2,$ $a_1=16$.

I have the following sequence:  $$a_{n+1}^2=a_na_{n-1}, \forall n \ge 1$$  With $a_0=2$ and $a_1 = 16$. I am also told that the sequence has positive terms. I have to find the limit of the sequence $(a_n)_{n \ge 0}$.  I am not that great at limits/sequences so I'm not sure how should I approach this.


URW-Garamond with mathdesign is typesetting vertical double-quote as vertical double-quote

I just started using URW-Garamond with mathdesign, and it's typesetting straight double-quote character as a straight double-quote rather than a right double-quote.  How can I fix this?  That is, when I put this in my header:  \usepackage[T1]{fontenc} \usepackage[urw-garamond]{mathdesign}   I get a nice Garamond in my output, but " in my input file produces a Garamond version of the same character in the output.  If I use two single-quotes instead, it comes out properly as a double right-quote.  I could switch to typing '' or set up a macro, but this is undesirable for more than one reason.  Is there any way to use urw-garamond without this non-traditional behavior for "?


Is there a Non-prime Number that is Divisible only by Numbers Greater than its Square Root?

Possible Duplicate:          The question is in the title. Is there a number that is divisible only by numbers greater than its square root? If not, why? I need this because it can speed up a calculation algorithm significantly if the answer is no.


Is there a way to view failed test reviews?

In your userprofile, you can view your reviews (activity -> reviews). It is not clear whether a review was a test, or a legitimate review. I think passed tests are included (I'm not sure though), but failed reviews are not.  In order to learn from my mistakes, I would like to review failed (and passed) reviews. Is this possible?  Another reason I'd like this, I would like to see how many failed review you get between bans. I think I failed only once since my previous ban, despite numerous passed tests, and over 100 reviews. But I lack the data to prove it.


Why are REIT stocks tanking and defaulting?

I have some REIT stocks in my IRA.  One of them just announced 2 weeks ago a normal dividend while their price was stable.  Within that time, it dropped 75%, then they announced they "can't cover their margins", their stock is now worth pennies.  How does that happen?  Why does it appear fine and 9 trading days later it's worthless.  There seems to be something about the REIT industry I'm missing as it's happening all over.


What would happen if you split an antimatter nucleus?

If we had the huge money required to make it, could it be used as a weapon more destructive than a regular nuclear bomb? Here it would undergo fission AND annihilate regular particles, so...?


I am going through the following sentence.  I looked up at my boss and his eyes were rivetted on me  google search auto corrects it to riveted. One of the meaning to rivet from Oxford is  direct (one’s eyes or attention) intently   rivetted (using double t - tt) is incorrect? In the above sentence what meaning best suits for rivetted?


No analytic function $f$ has modulus $|f(z)|=1/\cosh(\Re z)$

An analytic function $f(z) = f(x+iy)$ in $\mathbb{C}$ cannot have modulus $\frac{A}{\cosh(x)}$ for some constant $A \neq 0$.  Can we do so simply using the Cauchy-Riemann Equations?  I tried working by contradiction:  Say there is such a $f(z)$. Given $f(z) = u(x,y) + i v(x,y)$ is analytic, it satisfies: $u_x = v_y$ and $u_y = -v_x$  We also see that: $$|f(z)|^2 = u(x,y)^2 + v(x,y)^2 = (\frac{A}{\cosh x})^2$$  I tried reaching a contradiction, but seem to be getting lost in a mess of reformulations.   My start point is:  $$u_x = v_y \text{ and } u_y = -v_x$$ along with $$u(x,y)u_x + v(x,y)v_x = -A^2 \frac{sinh x}{(cosh x )^3}$$ and  $$u(x,y)u_y + v(x,y)v_y = 0$$  I would appreciate some hints!


Java Sqlite Database returning null pointer exception except returning data

I am writing a desktop application in Java and I am using a SQLite database. I am fetching data from SQLite studio, and it is fetched but when I get it in the application I'm getting a null pointer.   Below is the database manager class where the database is connected and functions related to db are called:  DB Class:  public class DBManager { Connection con=null;//build connection Statement stmt=null;//execute query static PreparedStatement pst= null; public DBManager(){     try {         Class.forName("org.sqlite.JDBC");         String url="jdbc:sqlite:mobileDB.db";         con=DriverManager.getConnection(url);         stmt=con.createStatement();     } catch (Exception e) {         JOptionPane.showMessageDialog(null, e);     } } public void insertUpdateDelete(String query){     try{         stmt.execute(query);     }catch(Exception ex){         System.out.print(ex.toString());     } } public ResultSet select(String query){     try{         ResultSet rs= stmt.executeQuery(query);         return rs;     }catch(Exception ex){         ex.printStackTrace();         return null;     } } public ResultSet getLogInRecord(String user,String pass, String role) throws SQLException {     String query="select * from Users where Username=? and Password=? and Role=?";     pst.setString(0, user);     pst.setString(1, pass);     pst.setString(2, role);     pst=con.prepareStatement(query);     ResultSet rs=pst.executeQuery();     return rs;  }   Function Calling:   btnLogin.addActionListener(new ActionListener() {         public void actionPerformed(ActionEvent arg0) {             try {                 String username=txtUsername.getText(),password=txtPass.getText(),role=cmbRole.getSelectedItem().toString();                 if(username.equals("")||password.equals("")||role.equals("Select")) {                     JOptionPane.showMessageDialog(frame, "Please input all the data. No empty data allowed.","Empty Fields",JOptionPane.ERROR_MESSAGE);                 }else {                     DBManager dbm= new DBManager();                     //ResultSet rs= dbm.getLogInRecord(username, password, role);                     ResultSet rs=dbm.select("select * from Users where Username='admin' and Password='admin' and Role='Admin'");                     if(rs.next()) {                         JOptionPane.showMessageDialog(frame, "True","Error",JOptionPane.ERROR_MESSAGE);                     }else {                         JOptionPane.showMessageDialog(frame, "False","Error",JOptionPane.ERROR_MESSAGE);                     }                 }             }catch (Exception e) {                 JOptionPane.showMessageDialog(frame, e,"Error",JOptionPane.ERROR_MESSAGE);             }         }     });


Why am I getting "line 1: $' :\r': command not found"?

I use Cygwin on my laptop (DOS). I have a collection of scripts from my colleagues, and my own. I am not an IT person, not knowledgeable in Unix. I am following my colleagues' syntax and able to manage a few simple things. The scripts worked well on my old laptop. I just changed laptop and installed Cygwin. When I run my scripts, they do not work. Here is one example of the error message I get: line 1: $':\r': command not found line 5: syntax error near unexpected token `$'\r'' line 5: `fi  Here are the top 5 lines of my script : iter=1 if [ -f iter.txt ]    then rm ./iter.txt  fi    Can someone please explain how I can get around this problem?


I think "was" is used for events , prettiness isn't an event , I expect : he told me that I'm pretty , why do we need the past tense with beauty ?   another question :   is there a book that talks about prepositions ? sometimes I dont know what to use after certain verbs , like : she gossips about me , at me , to me , crush into /in , it is bad to me / for me .. etc  I wish I could find it .


Meaning of and/or in Magic The Gathering

Mass Manipulation says:     Gain control of X target creatures and/or planeswalkers.   If I choose X = 1, can I target one creature and one planeswalker (having two targets in total)?  Or does it mean that I have to choose X targets in total?  This feels weird to me because if it's the latter case, why not simply write "or"? It would be less confusing to me.


difference between st_equals and equal sign

I have strange thing happening in postgresql DB. I would like to understand what is the major difference between using st_equals and using the equals (=) sign ex :  SELECT * FROM x WHERE st_equals(the_geom, st_astext('POINT(962952.534 6469066.353)'));   and  SELECT * FROM x WHERE the_geom=st_astext('POINT(962952.534 6469066.353)');   An this code will not be the same as   SELECT * FROM x where st_geohash(st_transform(the_geom, 4326))=st_geohash(st_astext('POINT(962952.534 6469066.353)'));   and not even the same as   SELECT * FROM x WHERE st_astext(the_geom)=st_astext('POINT(962952.534 6469066.353)');   I would like to understand why the result of these request differ  EDIT: so this question was mark as duplicate, I didn't found this post about st_equals and equal sign at the time. About converting to text with st_astext I was thinking about losing precision may cause the difference. But about st_geohash ?


How to get from Rovaniemi to Trondheim under the corona crisis?

How does one get from Rovaniemi, Finland, to Trondheim, Norway, without a car?   Finnish citizen residing permanently Norway, with pictures of relevant documents and a passport at hand. Not in a terrible hurry.   Some possibilities:   Can one fly from Helsinki to Oslo or Trondheim after taking a train to Helsinki? The flights are booked full for about a week, which is not ideal. Is there a way of getting to Troms/Tromsø/Tromssa and can one fly on (or even take a bus) from there? Is it possible to pass through Sweden? A ship from Vaasa/Vasa or some method the cross the border at Tornio/Torneå are possible ways of getting into Sweden, if it is possible. Is there a functional way of finding people travelling the same route or part of it by private car?


Why does logistic regression in Spark and R return different models for the same data?


Why package listings does not work with Beamer?

I want to show LaTeX code inside a Beamer presentation.  If I try the following MWE as an article, it works flawlessly:  \documentclass{article} \usepackage{xcolor} \usepackage{listings} \lstset {     language=[LaTeX]TeX,     breaklines=true,     basicstyle=\tt\scriptsize,     keywordstyle=\color{blue},     identifierstyle=\color{magenta}, }  \begin{document} \begin{lstlisting}      \documentclass{article}      \begin{document}      Hello World      \end{document} \end{lstlisting} \end{document}   However, the moment I want to use that code into a Beamer presentation like in the MWE below:  \documentclass{beamer} \usepackage{lmodern} \usepackage{listings} \lstset {     language=[LaTeX]TeX,     breaklines=true,     basicstyle=\tt\scriptsize,     keywordstyle=\color{blue},     identifierstyle=\color{magenta}, }  \title{A Tiny Example} \author{John Doe} \date{\today} \begin{document} \maketitle \begin{frame} \frametitle{First Slide} \begin{lstlisting}     \documentclass{article}     \begin{document}     Hello World     \end{document} \end{lstlisting} \end{frame} \end{document}   I get the following errors:   ! Missing \endcsname inserted.   ! LaTeX Error: Can be used only in preamble.


I'm not really sure when I read this book (or series of books), but it was definitely when I was a kid, so I'd say at least 10 years ago.  It's about a maze which when successfully navigated, gives the person great power. One of the powers that I remember was that a singer who had navigated through the maze was able to use her voice eventually to kill people. Eventually you find out that the maze was created long ago by some race known as the illuminati. It's set in a civilization that is less advanced than it previously was (some kind of downfall event occurred) but they still are able to travel between worlds. I specifically remember some threat that travels between solar systems and destroys the stars (by entering the stars and devouring it from the inside out). Sometime during the course of the plot the male protagonist gains the ability to travel through time and he witnesses the more advanced civilization in the past. There's a part where he is imprisoned with energy cuffs but he actually is able to escape but chooses not to and he plays with the energy cuffs by willfully changing the color of it using his mind as hes escorted away. You also find out that the star destroyer/devourer/whatever is actually a person specifically a woman (that got corrupted by the maze?).  This was read many years ago so some of the plot I listed might be slightly wrong. Sorry if I rambled...


One component in PCA is always the mean vector in two-dimensions but not three

I've been testing PCA via SVD to decompose a simple time series data matrix, $X$.  I have two signals $x_1(t)$ and $x_2(t)$ in a data matrix where $M$ rows represents each timepoint sample and each column represents $x_1$ and $x_2$.  The mean signal, $\hat{x}$, is defined as the mean along the row axis (average of $x_1$ and $x_2$ along each timepoint).  I normalize each column of $X$ by subtracting its mean and dividing by the standard deviation.  When I use [U S V] = svd(Xz) in matlab, regardless of how the variables are distributed (whether they are correlated or uncorrelated), one of the columns of the right singular matrix, V, always points in the same direction (to a multiplicative constant) as the mean vector $(1/2, 1/2)$.  But when add an additional third time series, this is never the case (where the mean vector is $(1/3, 1/3, 1/3)$.  Because I normalize the standard deviation for each vector, it does make sense that the direction of most variance given by PCA would be the diagonal 45 degree line.  But if both variables $x_1$ and $x_2$ are independent gaussians, couldn't the PCA direction be any direction since the distribution is radially symmetric?  MATLAB Code:  s = RandStream('mcg16807', 'Seed', 0); RandStream.setDefaultStream(s);  G = zeros(1000,2); G(:,1) = 40*randn(1000,1)-100; G(:,2) = tan(G(:,1)) + randn(1000,1); X = G - repmat(mean(G),[size(G,1), 1]); Xz = X./repmat(std(G),[size(G,1), 1]); [U S V] = svd(Xz); G_mean = mean(Xz,2); corrcoef(G_mean, U(:,1)) corrcoef(G_mean, U(:,2))


Help identifying this animation about a locked-down city overtaken by androids

I would've seen this in the early nineties. I think it was a movie, and only saw the end of it on TV (which probably means it wasn't new at the time).  There was a boy and a girl, and they were trying to escape a city that had been overtaken by androids. At the end, they were talking with what seemed to be the android in charge, won some kind of moral victory in their speech to it, and the androids all shut down and/or the walls keeping them in the city crumbled or exploded and they were able to escape.  The end titles had a sweet but sad song with female vocals, showing a montage of scenes from the movie.  As far as I can work out, it was not any Studio Ghibli production, and is definitely not Laputa. Though I'm pretty sure it was anime it may have been western style animation.  Update: I've just remembered an important detail! It turned out at the end that all these robots/androids were being controlled by a spoiled boy. It's possible I've actually made a dupe of this question, as the 'bubble' sounds familiar too:


Find $x$ in this $80^\circ$-$80^\circ$-$20^\circ$ triangle ($60^\circ$-$70^\circ$ variant)

Refer to the diagram and find x in degrees.  My method is to let AB=1, and express AD and AE in terms of AB using sine formula. Then find DE using cosine formula. After that use cosine formula to find cos x. Finally x=20 degrees. However this method relies on the calculator. Is there any PURELY geometric method to solve this problem, such as adding a line which is parallel to line AB, so that it can be PROVEN that x is 20 degrees, without the use of a calculator?


How to use template as argument in constructor while overloading operators?

I am making program in which I create class for vector and overload different operators. Now I want to make arguments of vector (coordinates) as templates.  When I have all code in one file everything is alright and program is running correctly:  #ifndef VECTOR4D_H_INCLUDED #define VECTOR4D_H_INCLUDED template <typename TYPE> class VECTOR4D{     public:        VECTOR4D (void): X(0), Y(0), Z(0), T(0){};        VECTOR4D (TYPE X, TYPE Y, TYPE Z, TYPE T): X(X), Y(Y), Z(Z), T(T){};        TYPE X, Y, Z, T;         VECTOR4D &operator+=(VECTOR4D &K){            this->X += K.X;            this->Y += K.Y;            this->Z += K.Z;            this->T += K.T;             return *this;        } };   #endif // VECTOR4D_H_INCLUDED   but when I separate implementation and declaration of overload operator I have a problem.  //vector4d.h #ifndef VECTOR4D_H_INCLUDED #define VECTOR4D_H_INCLUDED template <typename TYPE> class VECTOR4D{     public:         VECTOR4D (void): X(0), Y(0), Z(0), T(0){};         VECTOR4D (TYPE X, TYPE Y, TYPE Z, TYPE T): X(X), Y(Y), Z(Z), T(T){};         TYPE X, Y, Z, T;          VECTOR4D &operator+=(VECTOR4D &); };   #endif // VEKTOR4D_H_INCLUDED  //project.cpp #include <iostream> #include "vector4d.h"  VECTOR4D &VECTOR4D::operator+=(VECTOR4D &K) {     this->X += K.X;     this->Y += K.Y;     this->Z += K.Z;     this->T += K.T;      return *this; }   During compilation i have got an error:  invalid use of template-name 'VECTOR4D' without an argument list   How I have to do this to make it correct?


Increase the visibility of the association bonus by documenting it with the other privileges

Currently, the first time a user on the Stack Exchange network reaches 200 reputation, they get an extra 100 rep on that account and all their  accounts. I believe this should be documented as a privilege at 200 rep (along with the lessening of adverts).


How to prevent users from typing special characters in textbox

I need to validate a password entry on a textbox, I have a few demands to fullfill in order to allow the user profile to be created and one of them is to refuse registration if the password contains anything else different than numbers and the alphabet letters the system needs to deny the entry, everything I tried seems to fail. Here is where I'm standing right now:       private void BUT_Signup_Click(object sender, EventArgs e)     {      string allowedchar = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";      if (!(TXT_NewPassword.Text.ToString().Contains(allowedchar)))                     MessageBox.Show("No special characters on the password are allowed");


I am looking to make a kosher bechamel made from almond milk. What kind of fat should I use in the roux? Margarine? Regular veggie oil?


Using arrays as nodes for a graph with Tikz

I want to write a MPM graph for my students. For the moment, here is a short example of what I can do :  \begin{tikzpicture}   \node[draw,black] (A) at (0,1) {     \begin{tabular}{|c|c|}       \hline       \textbf{A} & (2) \\       \hline       \textcolor{blue}{0} & \textcolor{red}{5} \\       \hline       \textcolor{green}{5} & \textcolor{purple}{0} \\       \hline     \end{tabular}   };   \node[draw,black] (B) at (3,1) {     \begin{tabular}{|c|c|}       \hline       \textbf{B} & (4) \\       \hline       \textcolor{blue}{2} & \textcolor{red}{7} \\       \hline       \textcolor{green}{5} & \textcolor{purple}{0} \\       \hline     \end{tabular}   };   \draw[->,>=latex,black,very thick] (A.east) -- (B.west); \end{tikzpicture}   The problem is the following : if I don't use the "draw" option in defining the nodes, the arrows are not pointing at the right places. But if I use "draw", then I have an ugly rectangle around my tabular.  Is there a way that I can combine the best of both options ?  Thank you.


why $\{\omega \mid t\mapsto \omega (t)\ continuous\}$ not measurable?

Let $(\Omega ,\mathcal F)$ where $\Omega =\{\omega \mid \omega :[0,\infty )\to \mathbb R\text{ is a function}\}$ and $\mathcal F$ generated by cylinders, i.e. of the form $\{\omega \mid (\omega (t_1),...,\omega (t_n))\in B\}$ for some Borel set $B\subset \mathbb R^n$. Let $$C=\{\omega \mid t\mapsto \omega (t)\text{ continuous}\}.$$  Why $C$ is not measurable ? I tried by contradiction. If it's measurable, then there is a $B\in \mathcal B(\mathbb R)^{\mathbb N}$ and a sequence $(t_i)$ of $[0,\infty )$ s.t. $$C=\{\omega \mid (\omega (t_i))_{i\in\mathbb N}\in B\}.$$ I don't see where there is a contradiction.


Python how to search a list for all permutatio of a given input?

So basically my question is this. Let's say I have a list with values  l1st = ['dog', 'cat', 'bird', 'monkey']   And I ask the user to input   input = raw_input('Please enter the word you wish to search for: ')   Here's the big question. Let's say the person wants to search for   dog   but types it in as   Dog   I don't want the program to give him an error message just because he got the capitalization wrong. What is a method I could use for a list.index search to look for, if not the exact word, the closest similar word?


How can one display the FULL URL of his homepage?

I have already asked the question and got too much of a short answer, which didn't allow me to actually solve the problem. I'm sure that elaboration is needed, so more users could enjoy an answer. The question:  Is it possible to display the full URL of the home page in Drupal 7, like:   www.example.com/The-best-example-possible   I'd like to display the full URL of the home page as displayed above, and not only the Pure URL which in this case is:  www.example.com   How can that be achieved? what file\s should i go for doing that, where can such file\s be found?, what exactly to change, etc.  Thank you !


Cardinality of a set of subsets with given max cardinality

Let $S$ be a set of infinite cardinality $\kappa_1$. What is the cardinality $k$ of the set of subsets of $S$ with cardinality $\kappa\le\kappa_0<\kappa_1$? I understand that if $\kappa_0$ is finite, then $k=|S\times S\times\ldots \times S| $ (at most $\kappa_0$ factors), so $k=\kappa_1^{\kappa_0}=\kappa_1$. But does this still hold if $\kappa_0$ is infinite?  Thanks for any help!


Find the value of the following expression  $$ \prod^{\infty}_{n=0}\left(1-\frac{1}{2^{3n}}+\frac{1}{2^{6n}}\right)$$   What I tried:  If $\frac{1}{2^3}=x$, then we can write expression as   $$\prod^{\infty}_{n=0}(1-x^n+x^{2n})=(1-1+1)(1-x+x^2)(1-x^2+x^4)(1-x^3+x^6)\cdots$$  How do I find that infinite product


How to manage users and collections in MongoDB?

Im triying to create users in a database in mongo, I want to lock the usage of te collections for some users, I'll give an example:  Lets say that I actually have a db with 3 collections:  Books, Students, Proffesors  And 3 users:  Librarian, SecretaryManager, Director  And I want the Librarian have r/w permissions just in Books, SecretaryManager r/w permissions in Students and Professors, and finally, Director that would have the same permissions as Librarian + SecretaryManager.  I've readed the documentation of mongo main website, im aware of using db.adduser, but I haven't find the way of doing this or I've miss something.  Need help, thanks in advance.


I tried it by graph plotting, but it is going so ugly. On solving it on paper it mixed up. Is there any other process to solve?


If $\sum_{n=1}^{\infty}u_{n}$ is convergent and $u_{n}\ge 0 $ Then prove that $\sum (u_{n})^{2}$ is convergent


Grabbing the first [x] characters for a string from a pipe

If I have really long output from a command (single line) but I know I only want the first [x] (let's say 8) characters of the output, what's the easiest way to get that? There aren't any delimiters.


How to capture text from the operating system in a practical and simple way?

Sometimes we can't select the text to copy & paste, such as dialog boxes.  Sometimes it's just not practical, such as 100 files inside a folder.  Is there any practical and simple way to capture those text from the system into a text file?  I'd wish to know both in OS X and Windows. Maybe it just can't be done today...


Sentences like "I do believe" or "I do love you" are common. But I was wondering what do they mean? I've never seen structures like this in grammar.  In fact I don't understand what is the diference between these sentences and ,say ,this simple one: "I believe" or "I love you"  Thanks in advance.


Word for Impossible Solution to All Problems

I'm looking for a word to describe a solution that solves all problems, but such a solution is impractical or impossible.   For example, let this word be X: "Having a billion dollars is the X that would solve all my problems".   What candidates for X are there?


Is there a saying or proverb for a situation where the weakest party will always lose?

Yes this a repeat of a previous question, but I could not figure out how to post this answer, so I shall try to re-ask the question and answer it myself:     Book V Chapter XVII: "Sixteenth Year of the War—The Melian Conference—Fate of Melos"  is known as the Melian Dialogue, and is one of the most famous portions of one of the greatest books of antiquity.  Wikipedia describes it under the heading "Melian Dialogue" as follows:  "The Melian dialogue takes place fifteen years into the Peloponnesian war, during the confrontation in 416–415 BC between the Athenians and the people of Melos, a small island located in the southern Aegean Sea just east of Sparta. The Athenians demanded that the Melians surrender their city and pay them tribute or face the destruction of their city. The Melians claimed their right to remain neutral, appealing to the Athenians' sense of decency and mercy toward a small, peaceful, and defenseless city."  The Athenians said to the Melians:  "you know as well as we do that right, as the world goes, is only in question between equals in power, while the strong do what they can and the weak suffer what they must."  The Melians refused to surrender, so the Athenians defeated them, killed the adult men, and sold the women and children into slavery.


How do I reset a lost password (using recovery mode requires me to type the password)?

I need to reset my password. I have followed these steps:    However, then I go to "root" or "netroot" recovery options, it tells me:  Give root password for maintenance (or type Control-D to continue)   Clearly, I do not know the root password. If I type CTRL+D, I return to the list of options. From  I read:  Under chapter 'The Other Way':  4. Highlight the line that begins kernel and press 'e' to edit`   But in the grub configuration file I have no line that starts with kernel. Only:  setparams 'Ubuntu...' recordfail set gxfpayload... insmod part_msdos insmod ext2 set root=... search --no-floppy... linux /boot/vmlinuz-2.6.38... initrd /boot/initrd.img-2.6....   Those are all lines in my GRUB. Which line should I edit? Or is there another way to reset my password?


All three buttons enabled while reviewing again

I have gotten reviews in First Posts for posts that I have already taken an action on "in the wild".  The first time, I had commented on a post. When I saw the post come up in review, "I'm Done" was already enabled, and "No Action Needed" was disabled. This is cool.  You might assume the same thing would happen when I flagged a question for closure, then saw it again in the queue. It didn't. For some reason, I had three options enabled, and a lot of confusion:    I was able to complete the review when I clicked "I'm Done", at least.    From what it says , I'm not even sure if I should be getting these reviews:     As of now, if you have already taken some sort of action on a post, you shouldn't randomly come across it in the First Posts queue. However, if you directly navigate to it (via reloading the page, back/forward, or permalink), it should still be reviewable, with the I'm Done button enabled and clickable by default.   I reached the post through the review queue, not any of these methods:    reloading the page, back/forward, or permalink     The same bug was already mentioned at , but that was 4 years ago and a slightly different situation. The situation would have changed due to , obscuring the issue.


Did the writers know Odo’s heritage and the details of changing society from the start?

During the DS9 series the Changling/Dominion society becomes a key part of the narrative. I have been trying to look online and while I can see quotes about how Odo was written to take on the role of Data and Spock, a non human looking in on human society. I can’t find anything that explains when the writers fleshed out his backstory and came up with the idea of changlings being the society they became in the series?   Was it always intended that Odo would find his fellow changlings and they would then be the main antagonist or is this something that developed over time?


I was reading a  that any finite group can be embedded into the alternating group $A_{n}$, and it mentioned that in order to show this, it is sufficient to show that $Sym(n)$ can be embedded into $A_{2n}$.  Could somebody please explain to me why this is?


I just answered my own question, and am now viewing answer 1 of 0 - doesn't seem right!  Note this is both in the title bar, and the big bold "0 answers" line - unfortunately I can't add red freehand circles on the app...


Where do new ideas come from in research?

I am a PhD student working in computational theory which includes some amount of mathematics. I am currently in the middle stage. I have read a few research papers and have been working on some problem. I wonder how new idea's come into mind? I spend most of my time thinking about research problems again re-reading the problem statement and many times I try to read related works. I have been able to come up with new ideas but not something which is something like whole research paper. I try to focus as much as possible but still not focus is not working. I am wondering how researchers come up with new idea.   Question: How to to come up with new ideas or approach for research as a PhD student?   Some advice I have got is read-read and write and repeat but does not work for me.


Completing proof of derivative being continuous

Suppose that $f$ is continuous at $a$, and that $f'(x)$ exists for all $x$ in some interval containing $a$, except perhaps for $x=a$. Suppose, moreover, that $\lim \limits_{x \to a} f'(x)$ exists. Then $f'(a)$ also exists, and $$f'(a) = \lim \limits_{x \to a} f'(x).$$  Proof  By definition, $$f'(a) = \lim \limits_{x \to a} \frac{f(a+h) - f(a)}{h}.$$  For sufficiently small $h > 0$ the function $f$ will be continuous on $[a, a + h]$ and differentiable on $(a, a + h)$ (a similar assertion holds for sufficiently small $h < 0$). By the mean value theorem there is a number $\alpha_h$ in $(a, a + h)$ such that $$\frac{f(a + h) -f(a)}{h} = f'(\alpha_h).$$  Now $\alpha_h$ approaches $a$ as $h$ approaches $0$, because $\alpha_h$ is in $(a, a + h)$; since $\lim \limits_{x \to a} f'(x)$ exists, it follows that $$f'(a) = \lim \limits_{h \to 0} \frac{f(a + h) - f(a)}{h} = \lim \limits_{h \to 0} f'(\alpha_h) = \lim \limits_{x \to a} f'(x).$$  The suggestion is to apply a rigorous argument to the last step. To show that $\lim \limits_{h \to 0} \alpha_h = a$ it suffices to choose $\delta = \epsilon$ as then if $|h| < \delta$, then $|\alpha_h - a| < \delta = \epsilon$.   If $\lim \limits_{x \to a} f'(x) = l$, then for $\epsilon > 0$ there is a $\delta > 0$ such that if $|x-a| < \delta$, then $|f'(x) - l| < \epsilon$. Thus if $|h| < \delta$, then $|\alpha_h - a| \leq | (a + h) - a| < \delta$ so $|f'(\alpha_h) - l| < \epsilon$. Thus $\lim \limits_{h \to 0} f'(\alpha_h) = l$.   Is this correct?


Is this normal- time to issue assignment of accepted manuscript?

I'm writing to ask your advice on the time it normally takes for journals to assign an issue number to accepted manuscripts? Recently had a manuscript accepted, it is the first one I have published solo, and therefore the first time I have had to handle interactions with publication staff, etc. My manuscript currently appears as an Advance Article on the journal website, has been archived and the corrected article is due to be published tomorrow (after I followed up). I should mention it is now 4 months since the manuscript was first accepted. Is this normal?  With regards to issue publication, we are not able to provide a firm estimate regarding the print publication of your article, as a print publication is dependent upon issue assignment and the issue publication date. Issue assignment is ultimately up to the discretion of the journal’s editor, and articles are assigned to issues on a largely issue-to-issue basis. As your article has not yet been assigned to an issue, we are not able to provide a print publication date.  I kind of assumed that the manuscript would be included in the next issue of the journal (well, it's biweekly, so maybe the one after that, considering that the administration takes some time). What is your experience of issue assignment?


Why must a continuous function be null if its definite integral is null?

Let $ f(x) = \begin{cases} f:[a,b] \rightarrow\mathbb R  \\ \int_{a}^{b}f = 0 \end{cases}$. Prove: if $f$ is continuous, then $f\equiv 0$.  I'm still trying to get the intuition on the situation. For instance, if $f(x) = sin(x), x \in {[0, 2\pi]}$, it's true that $\int_{0}^{2\pi}sin(x) = 0$, but it does not imply $sin(x) \equiv0$. What did I misinterpret here? After the understanding of the situation, I'd like to know how would a formal proof follow.   I'm a freshman Pure Math student who barely started the course and has very few practice in writing proofs, although slightly less worse at reading them. I'd like a level of rigor in  line of thought.  EDIT: as it is noticeable from the comments below, there is a condition missing in the statement: $f \geq0$.


I have a problem with Sets/Iterators in Java. I'm executing code that iterates over elements in a hash set, removing them after they have been used but also removing elements that have been deemed unnecessary to iterate over within the loop. I'm also adding elements to the loop. Here's a code sample:  Set<Integer> thisSet = new HashSet<Integer>(); // add elements into set while (!thisSet.isEmpty()) {    int value = thisSet.iterator().next();    thisSet.remove(value);    // more remove and add operations }   I chose hash sets because I thought that the remove operations during the loop would be a lot faster than when using a list. The problem is that statistics show me that if the set gets large, polling a value from the set actually takes up a lot of time (I assume due to creating an iterator every time?). Does anyone have suggestions on how to improve this?  Thanks!


When traveling to a country with a different currency, how should you take your money?

Recently my wife and I traveled to Italy and before we left we got about 85% of our money in travelers checks and the other 15% we carried on in cash. When we arrived there, no one would take our travelers checks and many places did not accept credit cards. Eventually, we found some currency exchange places that would take the travelers checks and give us Euro's, but at a 7-15% fee, which was not really a very fun surprise.   While I was under the impression that it is safer to use travelers checks, it seems that they were not really accepted (the usual explanation being fraud). So the question is, is it best to just exchange your currency at home and carry all of it with you when you travel or are there other alternatives to carrying cash that are safer and cost effective?


Can I install Ubuntu 12.04 LTS on a PC with no OS?

I have a DELL OPTIPLEX GX620 with no OS and would like to try Ubuntu 12.04 LTS on it.  Can I do this?


Ubuntu 17.10 - Screencast always 0 bytes

I read that there is a feature to save videos using CTRL+SHIFT+ALT+R and I decided to try it:   I pressed the combination Did some silly things to get recorded  Pressed the combination once more I went to check out the webm file created   To my surprise, the video is 0 bytes big. How could this be? Do I have something misconfigured?  EDIT: To be clear, this problem affects only screencasting. Taking screenshots works without a problem.


What does Dumbledore's sign-off translate to?

In the Fantastic Beasts and Where to Find Them book the foreword is written by Dumbledore.   In the last he says      To wizards, I say merely: Draco dormiens nunquam titillandus.   Now Dumbledore is known for saying gibberish prior to the school feasts,  however this seems to be Latin or pseudo Latin.  What does the line mean in English?


Is this monster in Lost Mines of Phandelver too much for a group of level 3 characters?

My group of 8 level 3 players are about to run through the Thundertree Ruins and will probably have a hand at fighting the dragon. My question stems from the fact that a single poison breath attack from the dragon will outright kill all but 1 player assuming they fail their saving throws.  I understand this encounter is supposed to be ridiculously deadly, but I don't want to be punishing my players for testing the lengths at which they can fight stuff. A fight should be challenging and they should be able to try and run away, but instant obliteration seems a bit much.  All PCs are level 3 (HP in parenthesis):   Wood elf moon druid  (27) dwarven frenzy barbarian (44) fire genasi archer ranger (37) (pseudodragon companion (12)) wood elf assassin rogue (27) human wild magic sorcerer (22) dragonborn fighter (29) human monk (24) human fighter (32)


how to partition and install another distro side by side?

I would like to know how to install another distro side by side with Ubuntu 18.04.2.    Currently 18.04.2 resides on the entire hard drive.  Would I need to make another partition?  How would I go about doing this?  Would I be able to use the same GRUB menu?


Hiring Bitizens with Panna City Medicines as their dream job

I've unlocked the Panna City Medicines way back in December 2013. I have added 18 residential levels with two vacant slots each to increase my chance of finding a Bitizen with Panna City Medicines dream job. It's been 5 weeks and I've never seen any... Do they exist or just uncommon?


Late Schengen exit visa declined experience

Can someone share their experience of leaving schengen area late (specifically Budapest)?  I found that if you leave Schengen after your Visa expires, this is going to be recorded in their database and you are subject to a fine up to 500EUR. With the late exit record, your future applications for visa 'can be declined' (exact words the embassy representative used when explaining it to me). This sounds a little tricky because I don't understand what 'can be declined' means.  Can someone share their experience with the fine, passport check when leaving the country late and future visa applications with the late exit record?


Prove that n is divisible by 4 in a cylic sum with variables which have only two possible values

It is known that $a_1, a_2, a_3, ... , a_n \in \left\{-1, 1 \right\}$ and $S = a_1a_2a_3a_4 + a_2a_3a_4a_5 + ... + a_na_1a_2a_3 = 0$  Prove that $n \equiv 0\space(mod\space 4)$  I know this problem can be solved using number theory, but I am looking for a solution utilizing the concept of invariance.   I was able to identify an invariant of sorts: even if you change the sign of any $a_i$, the sum will still remain congruent to same number $mod \space 4$. It can be proved using this invariant that no matter what values you choose for each of the $a_i$, $S \equiv 0 \space (mod \space 4)$. It is not yet clear how I can prove the required statement using this result.


How to center div element (right: 50% Doesnt work)

I'm trying to center a div element, but when I use this:  position: relative; float: right; right: 50%; margin: 0 auto;   I get the following:    It just centers the right edge of the element and everything else goes to left.   Any ideas?


How to check if there exists a process with a given pid in Python?

Is there a way to check to see if a pid corresponds to a valid process? I'm getting a pid from a different source other than from os.getpid() and I need to check to see if a process with that pid doesn't exist on the machine.   I need it to be available in Unix and Windows. I'm also checking to see if the PID is NOT in use.


Existence in ZF of a set with countable power set

Is it consistent with ZF for there to exist a set $S$ such that the power set $P(S)$ is countable? If so, what is the weakest form of the axiom of choice needed to prove that no such set exists?


$C(X)$ is finite dimensional iff $X$ is finite

If $X$ is compact Hausdorff space and $C(X)$ is the set of all continuous complex valued functions on $X$,then prove that $C(X)$ is finite dimensional if and only if $X$ is finite.  My problem:If we suppose $X=\{x_1,x_2,...,x_n\}$ then how we can prove that $C(X)$ is spanned by the functions $e_i(x_j)=\delta_{ij}$ and $C(X)\cong \mathbb{C^n}$? And if we suppose $X$ is infinite then can I use the  solution () by replacing $\mathbb{R}$ by   $\mathbb{C}$?


Enlarging small photo for a large format print (banner)

I don’t have a lot of experience with large-format prints and was assigned a task of creating a wall vinyl banner 2,80 m × 2,92 m. I’m working on a smaller artboard in InDesign (25 % of given measurements). There’s a picture that I need to use and it’s quite small for this job: 15 cm × 17 cm, 300 dpi. How much could I enlarge it so that it would fill the good amount of the canvas but it wouldn’t be blurred or pixelated?  I would also appreciate the help with the text size on this project. What is the usual size for heading, body text, dates?


What are the drawbacks to withdraw incomplete Schengen Visa application?

I am an Indian passport holder and recently applied for a tourist Schengen visa to French embassy (from Singapore). However, I am not able to provide complete documents for the application. I took my passport because I have to travel for work. If I am willing to withdraw my application, does withdrawing application during the visa process reduce chances of Schengen visa in future?


Is there a way to search PDF files using grep, without converting to text first in Ubuntu?


I want to incorporate in my Blender interface (in my addon) a text box that allows you to write notes on several lines (as in the text editor script). Currently, what I find in Blender are text boxes on one line!


How can I make the arrows of a smartdiagram in the color of the box they are from, not to?

I want smartdiagram to use the color of the preceding box also for the arrow, instead of the box it is leading to. Therefore in this image:  I want the green arrow to be red, the blue one to be green, the orange one to be blue and the red one to be orange. How can I achieve this? Here is my MWE: \documentclass[border=3mm]{standalone}  \usepackage{smartdiagram}  \tikzset{     every shadow/.style={         fill=none,         shadow xshift=0pt,         shadow yshift=0pt} }  \tikzset{module/.append style={top color=\col,bottom color=\col}}  \smartdiagramset{%     module shape=rectangle,     text color=white,     border color=none, }  \smartdiagramset{set color list={red,green,blue,orange}}  \begin{document} \sffamily \smartdiagram[flow diagram:horizontal]{elem1,elem2,elem3,elem4} \end{document}


Cannot redirect to controller action method using HttpContext.Current.Response.Redirect(); from non-controller class

I've to redirect to the controller action method from non-controller class.  I am using HttpContext.Current.Response.Redirect();, it is redirecting me to my action method, but it's throwing an error      "Cannot redirect after HTTP headers have been sent".   public void MethodName () {      HttpContext.Current.Response.Redirect(url); }   I want to redirect form non-controller class void method.


cd command not working. Cant change directory in windows 10

I was using the cd command to switch my drive to E: which basically contains all my junk files which I use for experimentation but the problem was cd was not working. The command I used was  cd E:   ren *.* *.bat   However the time I ran this batch file (typed in notepad saved with a .bat extension) it didn't work out the cd command and ended up renaming all my desktop. When I tries using it in the command windows the result is  cd E: E:\   then nothing what should I do.


I'd like to be able to use latexdiff with git.  At the moment I have an alias in my .gitconfig file for a word-based diff:  [alias]  wdiff = diff --color-words   but is it possible to make an alias that will use latexdiff then compile the output and open the created dvi/pdf file?  Probably the best approach to this is using git difftool, but has anyone already made an appropriate script?


Describe a basis for the vector space of symmetric n x n matrices. What is the dimension of this space?


$$\lim\limits_{n\to \infty}({2^n\over n!}+2) * {n^2+n\over 2n^2+1} $$ I know that $$lim_{n\to \infty}{n^2+n\over 2n^2+1} $$ is 0.5 and the limit to the first part is 0. Thus is the limit of the whole equation just 0?


I’m taking Graph Theory lecture, and in the assignment there is a question about finding the determinant of a matrix $J_n-(1+\lambda)I_n$ where $J_n = (1)_{n \times n}$ and $I_n$ is the identity matrix of order $n$.   I have seen this problem before in the Linear Algebra course, and solved it by computing eigenvalues of the given matrix. However, since the final goal of this problem is finding eigenvalues of a complete graph $K_n$ by using this, it seems to be better to use different method.  I tried to use induction on the size of the matrix, but it does not seem to work well. I would be glad if someone give me a little bit of hint about this question.


Strong Mathematical Induction: Why More than One Base Case?

I am trying to understand this example of strong induction. I know normal induction. In normal induction, if base case is true then we assume some number $n$ to be true. Afterwards, we prove $n+1$ is true.  In strong induction, as you can see below, you prove more than 1 base case. I am not sure why. Then you prove $n+1$ is true...  I don't know why or how they choose however many base cases to prove or why proving extra base cases matters. Could someone please explain the inductive step of $3 + n - 2$? Where did it come from?


How do I make all dialog popups display on secondary monitor?

So I've been learning how to use Adobe Photoshop and I came across a unique problem. At first I thought Photoshop was bugging out and was getting frustrated considering I just bought Adobe Photoshop CC and your required to subscribe for one year (monthly payments). I noticed when I was trying to use image resize and my mouse turned square but the dialog box didn't popup, I kept force closing thinking it was a bug or something. Finally I restarted my computer and told it to NOT reopen windows. I opened photoshop, moved photoshop to my larger secondary monitor and tried again. And there the image dialog box was it had been popping under windows. I am using Adobe Photoshop CC 2017 on macOS and want to know if there is an option I can select to force all dialog popups for photoshop to open on the secondary monitor and not under other windows on my primary monitor.


Should we allow code touch up for syntaxic sugar

I know the rules of editing :    Do not touch the code Really, Do not touch the code!   But how should I treat an edit for syntactic sugar ?  Like changing :   if(true)   i.DoSomething();   To :  if(true) {    i.DoSomething(); }   (Or the other way around)  Is this a valid edit? Or is the rule that asks us not to touch the code apply to this kind of formatting too ?


Is there a significance to the number of rings given to each race?

Three Rings for the Elven-kings under the sky,      Seven for the Dwarf lords in their halls of stone,      Nine for Mortal Men doomed to die,      One for the Dark Lord on his dark throne      In the Land of Mordor where the Shadows lie.      One Ring to rule them all, One Ring to find them,      One Ring to bring them all and in the darkness bind them      In the Land of Mordor where the Shadows lie.   Everyone who has read the Lord of the Rings is familiar with the poem above. I am still making my way through the Silmarillion and will eventually get to reading the Unfinished Tales, which may hold the answer to my question: Is there any significance to the number of rings given to each race or is it just based on the number of kings/lords who ruled each race? Perhaps there is some information somewhere of why Tolkien chose these odd numbers or why the total number of rings is 20? Or perhaps there is no significance at all...


We have been led to believe that in the theory of universe expansion, the farthest object is moving faster away from us than the nearest object, attributing the difference to red shift.   Question: is it possible, due to the decay of light towards red, that the farthest object appears or is measured to have higher redshift?


I am not sure what is compared in this phrase but it seems that people believe it as the correct word.     She is nice, compared to you.      You're nicer, compared to him.   But why? What makes compared correct? Grammatically a past verb needs a subject right? She compared her car with the new one this one is grammatical correct, but this one is not The car is better, compared to her old car which one is the subject? As a beginner in english, I'd rather take comparing as it is not against what I've learned      She is nicer, comparing to you   Comparing is the act of to compare. A gerund doesn't need subjects:     swimming is nice.   It's not done there, the whole thing is getting worse after someone says that compared is not a preposition nor conjuction but a plain past participle, everytime I ask people they say that's correct BUT no one has been able to explain it.  I may be wrong as a very beginner English speaker but please help me to figure out regarding this problem, what is the state of compared here? Is that past participle, past tense, conjunction or preposition, and what is the rules that make it correct?, thanks in advance! It has driven my concentration recently.