While drafting an answer on another site, at one point I came up with the following sentence:  *You can’t force someone to follow a contract who hasn’t agreed to it.  I think the intended meaning is clear. But if you apply the grammar rules strictly, without regard for semantics, it would seem that the ‘who’ applies to the contract, which is a strange thing to say. Is this construction grammatical and does it have a distinct name?

Inside a prep book the following sentence is WRONG on the grounds that "that" modifies the closest noun "home".     John F. Kennedy, one of the most social U.S. presidents, held many parties in his family home that featured elaborate meals of local fish and lobster, famous guest and late nights.    However, in the same book, the following sentence is CORRECT with the reasoning that "that" is not restrictive and clearly modifies parties.     John held parties for his kids that featured clowns, numerous exotic animals, and lots of food.   What am I missing here?


What's the difference between them, and I know that their meanings or the same but I don't know how they both are grammatical.      I have no car.   I don't have a car.

Would you please tell me which of the following terms is correct? If both are correct, are they equal?     I have no [...] I don't have any [...]


Physicists say that energy is the ability to do work, and work is moving something against a force, like gravity. But what is energy? Is it something real? I know I will be criticised for using that word. But is it, maybe, something tangible? Or is it only an idea that we created to broadly name a phenomenon we observed? I could not find the answer as to what energy is!

The simplistic undergrad explanation aside, I've never really understood what energy really is. I've been told that it's something when converted from one kind of something to another kind, or does some "work", as defined by us, but what is that something?  Moreover, if the total amount of energy in the universe is finite and we cannot create energy. Then, where did it come from? I've learned from thermodynamics where it goes, but where does it come from?  I know this sounds like something trivially simple, but there is so much going on in the physical universe and I just can't grasp what it is. Maybe it is because I lack the mathematical understanding that I can't grasp the subtle things the universe is doing. Still, I want to understand what it is doing.  How do I get to the point of understanding what it's doing?  (Note: What prompted me to ask this was . I'm afraid that it just puzzled me further and I sat there staring at the screen for a good 10 minutes.)


Is the number constant or does it change as the reputation of a user grows?  I've been there, myself, in the beginning, I had my privileges revoked. I don't want to repeat such a thing.  Can we list factors that contribute to it, then?

If you are reading this, you may have been affected by one of our post quality bans. If so, it is important that you  to understand what has happened and how to regain the permissions that you lost. While trying to ask a question, one could see:  We are no longer accepting questions from this account. See  to learn more.  Likewise, for answers:  We are no longer accepting answers from this account. See  to learn more.   Why am I getting this message? Are deleted posts taken into account too? Is a question/answer ban the same as a suspension? How do I avoid getting a question ban? How long do I have to wait before I can post again? What can I do to release the ban? How can I reactivate my account? Can I simply create a new account? I'll just ask somewhere else on the SE network, and they'll migrate my question to the correct site! Will a ban on one Stack Exchange site affect my standing on other sites in the network? Does this apply to meta sites too? My account is in good standing. Why am I still blocked?


Running into a case where I need the user to confirm the canceling of an action. Not sure what the correct text here is for the button. 'Yes' and 'No' make the most sense to me but the Material Design guide  discourages that. Maybe I can change the main text? Anyway, what I have below is somewhat confusing. Any suggestions?

When attempting to cancel a service or setting, "cancel" is the default action. What should the normal "cancel" button be called?  Redbox uses a playful "just kidding", which may not be appropriate in all circumstances.


I have a custom Lookup component that will within another LWC. I need to retrieve the filter information for any lookups that has an active filter. I was able to retrieve data using getFilteredLookupInfo() and filteredlookupinfo. If the new custom lookup component results is based off a value that is selected on the original LWC. What information do I need from the filter to populate the new lookup component? For example the field metadata is this:  <filterItems>         <field>$Source.Account__c</field>         <operation>equals</operation>         <valueField>BrokerAccount__c.Account__c</valueField>     </filterItems>  Do I need to be able to get the valueField? Thanks, P

We are implementing a special type of lookup window in a VisualForce page, which displays a set of potential records a user can select from to populate a Lookup value. As a means to allow users to filter potential selections, we wanted to make use the Lookup Filter properties available when configuring a Lookup field.  The only problem is we don't seem to have any way to dynamically access these filter properties through Apex code. The Describe Field Result does not seem to contain this information, and I haven't been able to find anything in the documentation about it.  Is there no way to access Lookup Filter properties from the Apex Schema methods?


Let $K=k(x)$ be the rational function field over a perfect field $k$ of  characteristic $p > 0$. Let $F = k(u)$ for some $u$ in $K$, and write $u = \frac {f(x)}{g(x)}$ with $f$ and  $g$ relatively prime. Show that $K$ is  separable over $F$ if and only if $u$ is not in $K^p$.

Let $K$ be the rational function field $k(x)$ over a perfect field $k$ of   characteristic $p > 0$. Let $F = k(u)$ for some $u\in K$, and write   $u = f(x)/g(x)$ with $f$ and $g$ relatively prime. Show that $K/F$ is   a separable extension if and only if $u\notin K^p$.   There is already a post on this but it has not yet been answered :   The truth is that I am very confused with this problem, I would like someone please help me to understand what happens with this exercise and explain to me how it could be done by giving me a help or something. I already have an approach for the left-to-right implication, but I do not know very well how good it is. Could someone help me with the other implication please? Thank you very much.


If $f\in L^p(\mathbb{R^n})$ $1\leq p < \infty$ then prove $\displaystyle\lim_{|h|\to 0} \|f(x + h) - f(x)\|_p = 0$.  I had tried to prove the continuity a.e. of $\|f(x + h) - f(x)\|_p$, then could pass the $\lim$. This way is good or there is other more simple?

I am having a hard time with the following real analysis qual problem.  Any help would be awesome.  Suppose that $f \in L^p(\mathbb{R})$, where $1\leq p< + \infty$. Let $T_r(f)(t)=f(t−r)$. Show that $\lim_{r \to 0} \|T_rf−f\|_{L_p} =0$, that is $$ \lim_{r\to 0} \left( \int_{\mathbb R} |f(t-r) - f(t)|^p \mathrm d t\right)^{1/p} =0.$$


When you click on a link containing to a CSV file, Safari renders it by default.  Most other browsers will download them in this circumstance and I'd like to make Safari do the same.    What's the setting to make that happen?

Is it possible to fine-tune the "Open safe files after downloading" setting in Safari? For example, to make Safari open files like ".ical" et. al., but not Zip-files.  If macOS has no built-in support for this, could a solution be a UNIX script daemon that instantly detects new files in the Downloads directory and opens files with certain extensions?


First, I love SO. But, how can someone know how old a question is if the year is missing from all the dates?  It seems important to know how old a question is.  Am I missing it somehow? Thanks.

Seeing as how SO's one year anniversary is coming soon, question and answer dates are going to need to display the year.


I've mistakenly run "sudo chown -R $USER:www-data /". Now I can't login through ssh, it shows this message "ssh_exchange_identification: read: Connection reset". What should I do now?

I accidently ran  sudo chmod 755 -R /   instead of  sudo chmod 755 -R ./   I stopped it after few seconds, but now there is some problems such as  sudo: must be setuid root   How can I revert permissions back?


I want to import some .obj file that I have made with MeshLab. The point cloud file was actually in .pcd format and I used pcl_pcd2ply tools from PCL to change it into PLY-Format. Then I import it into Meshlab and make the mesh out of it. I used the texture and texture color as the object color. At the end, I have some file in MTL, PNG(for texture color) and the OBJ-Formats.  When I drag the OBJ file in Meshlab it shows the mesh with some color (before in point cloud just some random points). Then I tried to import the OBJ into Blender I could only see the mesh without the color. How can I solve this problem? Thanks in advance

I'm a new blender user, but have used other modelling programs before.   I've downloaded a  and unzipped it.   When I import the obj into blender, it is my understanding (from here: ) that the mtl should just import itself with it. However, when I import the obj, I just get a grey model with no texture. Is it actually importing the mtl but I'm not seeing it? Also for the record, I have changed no settings in blender.  Picture for reference:


Following scenario:  Two rockets leave a planet, heading opposite direction. Assuming the rockets are capable of accelariting highly - when would there be a barrier? Einstein said, nothing can be faster than light. But if both rockets flew with c/2 relatively to the planet, wouldn't they fly with c relatively to each other (which is not possible)?  Time is said to be faster for a moving object, but how is it determined whether an object is moved or not? I mean, there is no absolute place this can be measured from...

I understand that nothing can move faster than light due to time dilation. I want to build upon my understanding of Einstein's theory of Special Relativity, so I came up with this hypothetical problem for myself:  If both particles are moving at 0.9c towards each other (according to an observer on Earth), what speed does each particle have relative to the other?  I'm stumped since I am only familiar with Newtonian classical mechanics to solve this (which would be wrong). I am aware of Lorentz' factor $\gamma =\frac{1}{\sqrt{1 - \frac{v^2}{c^2}}}$ and the time dilation equation $t_m = \frac{t_o}{\sqrt{1 - \frac{v^2}{c^2}}}$, but I'm not sure how to apply it in this instance. I'm just looking for a gentle push in the right direction. Edit: My prior research:  This article, ,  talks about the effect of a baseball thrown at 0.9c would have as it traveled towards a batter. This is not what I'm looking for since it doesn't explain the math behind finding the collision speed between two high velocity entities.  This question on Yahoo, , asks a similar question to mine, but no math is involved to demonstrate the calculations behind the reasoning.  This question on Physics.SE, , does not answer my question either. I have not been able to find a similar Physics.SE question which can provide me to clues to my own hypothetical question.  I have also Googled the following phrases:    i. "collision faster than the speed of light" ii. "collision of high speed particles" iii. "lorentz transformation in a collision" iv. "collision analysis at light speed"


I am working on a project and there I am getting a value from input tag and then insert input value in a div and appending on screen with children element.  And What I want that when user click on children element then parent div would be removed and for this I'm using a function. That is working when I am using by default a section but when I append a section and then click on that's children where a function call like when user click on it's children parent section would be removed but my functionality not working.    $('#btn').click(function() {   var menuFieldName = $('#text').val();   $('.div').append('
' + menuFieldName + 'X
');   $('#text').val(''); });  $('.div .a span').on('click', function() {   $(this).parent().remove(); }); .a {   display: inline-block;   padding: 5px 35px 5px 10px;   position: relative;   background: #eee;   border-radius: 20px;   margin: 10px; }  .a span {   position: absolute;   top: 0;   right: 0;   background: #333;   color: #fff;   height: 28px;   width: 28px;   text-align: center;   line-height: 28px;   border-radius: 30px; }

Test X

  <input type="text" id="text"> <button id="btn">Add</button>

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


Trying to run Jekyll on a Google Compute Engine VM instance. It runs a server on port 4000. I have created a firewall rule to allow incoming traffic from this port, but all my connections get refused for some reason. What else should I be looking at?

This is a  about Connection Refused    We see a lot of questions to the effect      When I try to connect to a system I get a message      Connection refused      Why is this ?


Let $$a_n=\left(1-\dfrac{1}{\sqrt2}\right)\dots \left(1-\dfrac{1}{\sqrt{n+1}}\right),n\ge1$$ Then find $\lim_{n\to \infty} a_n$.   How can I proceed? I am stuck at the first step. Please help.

I am not being able to find the specific product $\prod_{r=1}^{k} \left(1-\frac{1}{\sqrt {r+1}}\right)$ so to evaluate the given problem when $k \to \infty $.


If I am playing a game on Xbox One, can I chat with a friend that is on Xbox 360?

I have an Xbox one and my brother has an Xbox 360.  I couldn't figure out how to join his party or invite him to mine, or even initiate a private chat.  Is this possible or am I missing something?


Find  angle $ \angle AED  $ in the following triangle.  In the above triangle we have : $CA=CB ,CE=DB=BA ,\angle ACB =20^° , \angle CAB=\angle CBA=80^°$ now find $ \angle AED  $.  I think if we draw line $AD$ we have $AB=BD$ then $\angle BAD= \angle BDA =50^°$ then in the triangle $ AED$ we have $\angle EAD=30^°$ but I can't find $ \angle AED  $

$ABC$ is an isosceles triangle, $AB=AC$, and $\measuredangle A=20^{\circ}$. For point $M$ on $AB$ and $N$ on $AC$, we have $AM=NC=BC$. Compute the  $\measuredangle BMN$.  In a similar problem (with only one point on one side) the key step was to construct an equilateral triangle on the other side. I tried using that in this problem too, but I didn't manage to solve it.


float a = (float) 3.32 ;      float b = (float) 4.32 ;      System.out.println(b%a);   output on my machine is 1.0000002  Why ?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


Without knowing ahead of time that I'll want to do this, is it possible to wait for a job to finish and automatically begin executing another one?  For example, I jump into a tmux session and execute sudo apt update && sudo apt upgrade.  Then I create a new pane and begin doing something, only to realize I need another package on my system I don't currently have.  I have to wait for my update/upgrade process to finish, but it's chugging away and I don't want to have to wait for it, especially since I could be doing something else while it's going, rather than having to wait for it.  I'd be fine with ^Z and bg-ing the job, but my question is, is there a way to insert a job after that job is finished, so that I can && sudo apt install tree for example?  EDIT: this question is different from the linked question and answer, I think, because job1 && job2 ^Z fg; echo "done" will see echo "done" executed after job1 finishes: job2 apparently gets discarded.  The way around it is to use a semicolon between job1 and job2, but that's not a great solution for me.

Job control is probably my favorite thing about Linux. I find myself, often, starting a computationally demanding process that basically renders a computer unusable for up to days at a time, and being thankful that there is always CTRL-Z and fg, in case I need to use that particular computer during that particular time period.  Sometimes, however, I want to insert a job onto the job stack. I've never figured out how to do that.  I'm using bash.   It would probably look something like:  $ ./reallybigjob ^Z [1]+  Stopped                 reallybigjob $ (stuff I don't know) && ./otherbigjob $ fg


I want to estimate two models, Vector Autoregression (VAR) and Vector Error Correction Model (VECM).  What is the correct way to choose lag length / lag order?  For the VAR model, I have selected the lag ($p=4$) using:    variables at first difference  statistical criterion  AIC  no evidence of autocorrelation or  heteroscedasticity in the residuals.    For the VECM model, I have selected the lag ($p=1$) using:    VAR with variables at level,  statistical criterion of AIC,  no evidence of autocorrelation or  heteroscedasticity in the residuals of VAR,  lag of VECM equal lag of VAR in level minus 1, VECM(0).    Is this methodology correct or in error?

Question 1: Is it necessary to consider AIC and the BIC criteria when selecting the lag for a VAR, VECM or ARDL model OR can I use something else?  Example: Can I pick 12 lags because the model simply produce great results when I do or do I have to use the AIC/SIC criteria?  Question 2: A simple google search tells me that its possible to select lag 4 when quarterly data, 12 when monthly etc. Is that a valid approach ?


Is there any way of not copying the specific array in the foreach loop?  Here's the code   <?php      $letters = array("A","B","B","C");        foreach ($letters as $char){         if ($char == "B") {           continue;          }         echo $char;       }  ?>   I want my output to be only ABC not AC

How can I remove duplicate values from an array in PHP?


Been looking high and low for a solution to creating a diagrammatic animation like this. I have use of SketchUp, Lumion, Rhino, Adobe Suite - but not 3DS Max which is what I imagine this was originally made in. Would really love to know if I could make it in Blender and if there were any basic tutorials on how to create this style? Always wanted to learn Blender!

Since asking for tutorials, videos, resources, links to other content or downloads is considered off topic here, this is a specifically created Community Wiki which gathers resources for Blender and it has been approved by the .  Just write in the appropriate answer/section. If you have concerns, questions, post a  question, so we don't clutter the comments, but you can link your meta question from the comments.  Questions regarding such resources are not allowed anymore, except for very specific and on topic requests (ask on  if you're unsure about your question). Follow the instructions made in the question about how to post, what can be posted, etc.  Learning             Assets    (also see: )   Reference Images/Blueprints (also see: )    Tools    (also see: )      Other   Special Interest ()     Also see the .


Hear me out. When asked what is mass made of, I can roughly say it is the interaction between the particle and higgs field or energy of quarks, boson, what have you. Now I ask what is charge made of? How can I describe this phenomenon with or without electric field? Because charge give rise to electric field but it is not the electric field.

Baryons have charges that are the result of a polynomial calculation of their building blocks (quarks)'s fractional charges. But what gives these quarks electric charges? What interactions do they have with photons? And what about leptons, like muons and electrons? How do they get their -1 charge? And then, how do positrons and anti-muons get +1 charge? Same goes for quarks: how does up-antiquarks get -2/3 charge? Or I may want to formulate my question this way:  How does any elementary particle interact with the EM-Force to get an electric charge?


I am wanting to install Lubuntu on a bunch of computers and laptops. I would rather not through each individual installation and change the settings to how I want them. Is there a way to set the settings prior to installation on the installation disk (which is a USB)?

I've been trying to preseed my installation for 2 days now. I'm quite new in this topic, so execuse me if I'm asking noob questions. How do I use boot parameters, how do I know that my preseed file works. When is my preseed file loaded


I just upgraded my PC from Windows 7 to Windows 10.  I did a fresh install to avoid any issues, but unfortunately it's been nothing but problems.  The PC freezes for about 10 seconds every 10 seconds.  When it freezes, I can move the mouse pointer, but nothing responds, not even ctrl+alt+delete.  After 10 seconds of doing absolutely nothing, it seems all my inputs happen at once.  This happens consistently every time I boot.  The only things I've installed are:   All the latest drivers The latest Windows updates (v1803)   I don't have an anti-virus, firewall, or anything else yet.  Specs:   Motherboard: Asus Maximus IX Hero CPU: Intel i7 7700k GPU: Nvidia GTX 980 TI   So it's fairly beefy.  The same hardware just worked fine in Windows 7, so it's not a hardware issue.  One thing I've noticed is that the System process is at 15% (> 100% of one CPU core) at all times.  Based on recommendations here, I ran Process Monitor and discovered the faulty thread is called ntoskrnl.exe!rtlavlremovenode.  Unfortunately googling that doesn't produce anything useful.  Has anyone seen this before?

I have noticed that from some time my system is freezing and its probably caused by the high CPU usage which is caused by the system process.  All applications I'm running is the Skype, TeamSpeak and Chrome so it definitely shouldnt eat that amount of CPU.  You can see the problem itself and running processes in the screenshot below:    Sometimes CPU usage is reaching 90%, but the average usage is like 40-65%.  My PC parameters:   Windows 8 (customer preview) Intel Core i3 - 2350M 8 GB RAM   I'd appreciate any help attempt! Regards.  --UPDATE--  As the user below posted a great answer, I have noticed that the process that is eating the most CPU in the system is called Arthurx.sys, simple google tells that it's a TPLink driver (an wifi adapter, I have bought like 2 weeks ago!) drivers has been installed from the Windows MSDN, but also tried to install the drivers from the attached CD, but it doesn't help. From the system start, it is using like 5% of the CPU only, but after 2-4 hours of working it is growing up and reaching 40-60% of the CPU usage.  Device name: TPLink WN722N


Across the different versions of Pokémon, Eevee has many evolutions. Is it possible to choose what evolution we get when we evolve an Eevee?  From :     Umbreon when leveled up with high friendship during the nighttime   (Generation II onward, excludes areas with a Moss Rock or Ice Rock),   or when leveled up with a Moon Shard in the Bag (Pokémon XD).      Glaceon when leveled up near an Ice Rock (Generation IV onward).   We don't have Moss or Ice rocks, just Eevee candies. Is the evolution in Pokémon GO random, or is there a way to control which evolution is chosen?

So I just caught an Eevee. Now, I need 25 candies to evolve it. The fact is that in the GameBoy color versions, that Pokémon needed a stone to evolve instead of experience. Depending of the stone he was fed with (thunder, water or fire), he was evolving in a different Pokémon.   Is the stone feature also in Pokémon Go? If not, what decide the evolution of this Pokémon?   Bonus point : If it's possible, how can I get a stone?


I know when black holes collide, the remnant black hole has a lower mass than the sum of the original two masses. This is due to energy loss via gravitational wave emission.  Does this violate the information paradox? Does this mass come from inside the black holes? I’ve seen some explanations saying that it’s due to relativistic mass from the black holes moving, is this correct? Is this real mass loss? An explanation would be appreciated.

Since the final Black Hole (BH) had 3 solar masses less of mass than the original binary BH, it seems the 2 BHs lost mass, and with it event surface area, entropy, and information. If that came from inside the BHs it seems that it would be a contradiction of what a BH is --'nothing escapes its event horizon'. Some may say that came from the rotational energy of the pair, but the new BH now seems to have less than the two original ones summed. So, did some of that escape the horizons?


Crystal Report (8.5) is not working on win7/windows 2008 64 bit system   My application is a VB application and I am using Crystal report 8.5. It is working fine on 32 bit system and 64 bit system of Windows 2003 server. When I run the same application either on win7 64 bit or on 2008 64 bit, report does not open. I am using vb script to access the database.  Part of the code written in the VB script file is as follows:  Dim objrsRecordSet                 'As RecordSet Dim strSQL                         'As String  '**** Open Database Connection using the parameters passed from the main program Set dbConnection = CreateObject("ADODB.Connection") dbConnection.ConnectionString = "Provider=SQLOLEDB;Server=" & mstrServer & ";uid=" & mstrUserName _                                 & ";pwd=" & mstrPassword & ";Database=" & mstrDatabase & ";"  dbConnection.Open dbConnection.CommandTimeout = 200  dbConnection.Properties("Enable Fastload").Value = True   When I run my application in debug mode it is working fine on windows 7 also. But when I run the application through the set up by consuming the .dll of crystal report then it is not working, in this case report is not opening.  Please help me out with this issue, i will appreciate for your response.

I have successfully installed Crystal Reports 8.5 on my Windows 7 desktop, but when I try to launch the application i get this:    Any experience with this?  Besides the obvious "update to as newer version", does anyone have any suggestions?


On the Board and Card games chat site, the account suspension message is very difficult to see. In my browser (Chrome on Linux) it looks like this:    For anyone who has trouble seeing it, that says     your account has been temporarily suspended by a moderator and cannot chat for 18 hours 53 minutes.

I was conducting some experiments on my sockpuppet, which included handing out a chat suspension to... well, myself, on another account. I discovered, however, that the "your account has been suspended" message that shows up is unreadable:    Highlighting the text, I can see what it says:     your account has been temporarily suspended by a moderator and cannot chat for 59 minutes.   But otherwise, only the two words "your account" are visible, leaving users possibly confused about why they can't send any messages and why there's a link to their chat profile showing up instead of the textbox.


This has been asked many times, but is there any new methods to find out the time when the row was inserted in Oracle Database?  I have already tried to find out using ORA_ROWSCN. But its not accurate. It shows the updated date i believe and dose not show if the row is inserted before a long time.  The previous designers thought that its not necessary to include the Date added and Date updated columns when they were designing the Database.  This has caused a lot issues when it comes to analyzing the data and auditing.  Please help, this would make my day.   Thanks in Advance  :

Can I find out when the last INSERT, UPDATE or DELETE statement was performed on a table in an Oracle database and if so, how?  A little background: The Oracle version is 10g. I have a batch application that runs regularly, reads data from a single Oracle table and writes it into a file. I would like to skip this if the data hasn't changed since the last time the job ran.  The application is written in C++ and communicates with Oracle via OCI. It logs into Oracle with a "normal" user, so I can't use any special admin stuff.  Edit: Okay, "Special Admin Stuff" wasn't exactly a good description. What I mean is: I can't do anything besides SELECTing from tables and calling stored procedures. Changing anything about the database itself (like adding triggers), is sadly not an option if want to get it done before 2010.


Somewhere on Stack Exchange I saw the equation     $$\gcd(2^m-1,2^n-1)=2^{\gcd(m,n)}-1.$$   I had never seen this before, so I started trying to prove it. Without success...  Can anyone explain me (so actually prove) why this equation is true?  And can we say the same when replacing the '$2$' by any integer number '$a$'?


I am looking for a Java equivalent of pointer-comparison in C/C++.   Suppose I am invoking a getSomething() method of an object of a class from a third-party. How do I know if the implementation of the getSomething() is just returning the same instance everytime or returning a different instance of the object?  I am not looking to check whether two objects are identical, but need to check if they are the same instance or not. The motivation is, if the 3rd party implementation is creating a new instance everytime, probably I can optimize my code by not invoking the method everytime. Assume getSomething() is invoked by me 1000s of times a second at run-time  From what I read from various articles, I shouldn't rely on hashCode(). In that case what is the way to do this?

Let's say that you have overridden an object's equals() and hashCode() methods, so that they use the object's fields.  How you do you check if two references are to the same object, ala the stock equals() method?


It is known (see, e.g. Wikipedia) that the transition to Bose-Einstein condensate occurs below critical temperature: $$  T_c \approx 3.3125 \, \frac{\hbar^2 n^{2/3}}{m k_B} $$ where $n$ is the particle density in the system.   It is obvious that higher particle densities $n$ correspond to higher critical temperature $T_c$.  Nevertheless, it is always stressed that Bose-Einstein condensation has been achieved with ultra low density quantum gases (1/100000 of the density of normal air).   So my question is: Why? Which is the obstacle that prevents experimentalists from trying to Bose-Condense denser gases?

I've just begun reading C. Pethick and H. Smith's textbook "Bose-Einstein condensation in dilute gases" (Cam. Uni. Press). In the Introduction, they contrast the density of atoms at the centre of a BEC cloud to other phases of matter. To quote from the text (pg 1, 2nd ed.):     The particle density at the centre of a Bose-Einstein condensed atomic cloud is typically 10^13–10^15 cm^−3. By contrast, the density of molecules in air at room temperature and atmospheric pressure is about 10^19 cm−3.   This has puzzled me, as instinctively I think the density of the BEC should be higher because the atoms are macroscopically occupying the ground state and would have a smaller separation between atoms than a 'warm' classical gas.   Why is the density of a BEC lower than normal phases, despite the large degree of occupation?   Answers on this thread state it is because of the large positional uncertainty of the atoms in the BEC: . But as far as I can see, this will only ensure the density of the BEC is uniform.  As a beginner to the subject, I would greatly appreciate if someone can help me to resolve my conceptual difficulty.


I'm making a framework for building GUI apps with tkinter and in my code I have a Scene class that has a add(widget,params) function which creates a tkinter widget and adds it to the Scenes widget dictionary. But I can only add a widget that I have built an add() function for because different widgets have different named parameters. how would I make a function that takes a dictionary in the form {paramName,value} which would then pass it to the widget function for example scene.add(button, {'command':Click, "text":"click me"} )  my current code is import tkinter as tk  class scene():     def __init__(self, title, width, height):         self.widgets = {}         self.title = title         self.width = width         self.height = height      def add(self, name, type, widget, root, params):         if name in self.widgets.keys():             return         else:             if type == "button":                 width = params[0]                 height = params[1]                 text = params[2]                 self.widgets[name] = [widget(root,width=width, height=height,text=text),params[2:]]      def get(self,name):         if name in self.widgets.keys():             return self.widgets[name][0]

I'd like to call a function in python using a dictionary.  Here is some code:  d = dict(param='test')  def f(param):     print(param)  f(d)   This prints {'param': 'test'} but I'd like it to just print test.  I'd like it to work similarly for more parameters:  d = dict(p1=1, p2=2) def f2(p1, p2):     print(p1, p2) f2(d)   Is this possible?


I'm not a pro in OOP so please bear with me.  This piece of code is from android's auto generate Master/Detail Flow project :  static {         // Add 3 sample items.         addItem(new DummyItem("1", "Item 1"));         addItem(new DummyItem("2", "Item 2"));         addItem(new DummyItem("3", "Item 3"));     }   What is that? I mean is it a method?a constructor?or what?

My question is about one particular usage of static keyword. It is possible to use static keyword to cover a code block within a class which does not belong to any function. For example following code compiles:  public class Test {     private static final int a;         static {         a = 5;         doSomething(a);     }     private static int doSomething(int x) {         return (x+5);     } }   If you remove the static keyword it complains because the variable a is final. However it is possible to remove both final and static keywords and make it compile.   It is confusing for me in both ways. How am I supposed to have a code section that does not belong to any method? How is it possible to invoke it? In general, what is the purpose of this usage? Or better, where can I find documentation about this?


I want to instantiate a Java hashmap with literals in Java.  I am using Java 8.    I have seen from Functional Programming in Java book that you can do this with Lists:  final List<String> cities = Arrays.asList("Albany", "Boulder", "Chicago", "Denver", "Eugene");   But I haven't seen how you can do a similar thing with hash maps.  I can create the hash map like this:  import java.util.HashMap; import java.util.Map;  public class ShortestPath1 {     public static void main(final String[] args) {         final Map<String,Integer> station2nlc = new HashMap<String, Integer>();          station2nlc.put("Ealing Broadway", 319000);          station2nlc.put("Ealing Common", 319005);          station2nlc.put("Acton Town LT", 50000);          station2nlc.put( "Chiswick Park LT", 54500);          station2nlc.put( "Turnham Green LT", 73400);         station2nlc.put( "Stamford Brook LT", 71300);          station2nlc.put( "Ravenscourt Park LT", 68200);          station2nlc.put( "Hammersmith LT", 59300);         station2nlc.put( "Barons Court LT", 51600);          station2nlc.put( "West Kensington", 76000);          station2nlc.put( "Earls Court LT", 56200);          station2nlc.put( "West Kensington LT", 76000);           System.out.println("Ealing has NLC: " + station2nlc.get("Ealing Broadway"));     } }   But this syntax implies that Java is building the hashmap per line instruction.  Which it probably is.  For comparison, the example below in C++ is what I was thinking would be possible:  #include <string> #include <unordered_map> #include <iostream>  int main() {     std::unordered_map<std::string, int> station2nlc(     {         { "Ealing Broadway", 319000 },         { "Ealing Common", 319005 },         { "Acton Town LT", 50000 },         { "Chiswick Park LT", 54500 },         { "Turnham Green LT", 73400 },         { "Stamford Brook LT", 71300 },         { "Ravenscourt Park LT", 68200 },         { "Hammersmith LT", 59300 },         { "Barons Court LT", 51600 },         { "West Kensington", 76000 },         { "Earls Court LT", 56200 },         { "West Kensington LT", 76000 },     });      std::cout << "Ealing has NLC: " << station2nlc["Ealing Broadway"] << std::endl; }

How would you initialise a static Map in Java?  Method one: static initialiser  Method two: instance initialiser (anonymous subclass) or some other method?  What are the pros and cons of each?  Here is an example illustrating the two methods:  import java.util.HashMap; import java.util.Map;  public class Test {     private static final Map<Integer, String> myMap = new HashMap<>();     static {         myMap.put(1, "one");         myMap.put(2, "two");     }      private static final Map<Integer, String> myMap2 = new HashMap<>(){         {             put(1, "one");             put(2, "two");         }     }; }


I noticed that after compiling a document using TeXWorks and PDFLaTeX (I made a clean install less than a month ago) there seems to be a strange kerning issue whenever "f" and "i" appear next to each other in textmode and I have no idea what is causing it. If I compile the text and try to highlight it in a pdf reader, it seems to treat "fi" as its own character and I cannot highlight just the "f" or the "i". In all other cases the kerning seems fine.  \documentclass[11pt]{amsart} \usepackage{graphicx} \usepackage{epstopdf} \usepackage{amsthm} \usepackage{amsmath} \usepackage{amssymb} \usepackage{amsxtra} \usepackage{amscd} \usepackage{verbatim} \usepackage{rotating} \usepackage{multirow} \usepackage{multicol} \usepackage{url} \usepackage[all]{xy}  \begin{document}  identities for modified lattice paths by establishing a bijection \end{document}

The  package allows to completely suppress ligatures. However, this feature requires pdfTeX 1.30 or newer. That's unfortunate if I'm using LaTeX or XeLaTeX while having to avoid ligatures.  Is there any other way to disable ligatures for a complete document or just an environment?


I tried to install npm package but it still gave the same output :  I even try this solution :  but still the same error occured ! plz help me !

After upgrading from 10.04 to 12.04 I am trying to install different packages.  For instance ia32-libs and skype (4.0).  When trying to install these, I am getting the 'Unable to correct problems, you have held broken packages' error message.   Output of commands:  sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   After running this:  sudo dpkg --configure -a foo@foo:~$ sudo apt-get install -f Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


I am a US citizen w/dual Italian citizenship traveling over 6 months in Europe.  I will be establishing Italy as primary stay although, my husband (USA citizen) does not have an Italian citizenship.  We want to travel for 6 months to a year throughout Europe.  My question is, what are the rules for him?  Does he need an extended stay visa or can he attach himself to me (I have an EU passport) since we are married?

I am an Australian Citizen travelling with my wife (with dual passport Australian and UK) to the Schengen area. We will be travelling together in a camping car and intend driving around various countries for approximately 4 months. Then returning to the UK before returning to Australia. Do I require an extended stay Schengen visa or am I covered, as I will be travelling with my wife on her UK passport? How and where would I a apply for the appropriate visa?


I was asked to prove the following : Let $G,H,$ and $K$ be finite abelian groups. If $G \times H \cong G\times K$ then $H\cong K$. It seemed very intuitive to me but I am having a hard time writing it formally. I found this :  which is the same question but the explanation there is not really formal and I feel as if they only reduced the problem to an equal one: 1. first me decompose to cyclic groups 2.we say that G is of course decomposed in the same way in the two products 3. since the decomposition are isomorphic and G's decomposition is the same we conclude that K's decomposition is isomorphic to H's decomposition. But isn't it the same as saying the same argument without decomposing at all? What am I missing here? What does the decomposition really gives us apart from writing the same thing in a different way?

Let $G\times K$ be a finite group. Suppoose $G\times K\cong H\times K$. Is this sufficient to imply $G\cong H$?


Firstly, I know that there is a question on switching cards after charging rent on them. However, the case I did is a bit more extreme.  I had 2 green, 2 red, 2 light blue, 1 yellow, and a multi-colour wild property card.  Firstly, I moved the wild card from its original position, with the yellow, to the green and make it a full set. (This counts as 0/3 of my moves.)  Then, I charged everyone 7M each. (1/3)  After receiving the money, I moved the wild card to the red set, and charged everyone 6M each. (2/3)  After receiving the money, I moved the wild card to the light blue set, and charged everyone 3M each. (3/3)  Then, I moved the wild card back with the yellow card.  Is any part of my moves out of the Monopoly Deal rules? Although I don't think so, people are saying that I might have cheated.

If you have one property and another wild card, can you put them together as a set and charge rent on them, and then place the wild card separately, all on your turn? (to save your set from a deal breaker card)


I have the following simple python code:  arr1 = [[0]*4]*4  arr = [[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0]]  print arr print arr1 print arr1 == arr  for x in range(0,3):     arr[1][1] = 1   for x in range(0,3):     arr1[1][1] = 1   print arr print arr1 print arr == arr1   This code produces the following output:  [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]] [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]] True [[0, 0, 0, 0], [0, 1, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]] [[0, 1, 0, 0], [0, 1, 0, 0], [0, 1, 0, 0], [0, 1, 0, 0]] False   Could someone tell me why the output is different and why the arrays aren't equal anymore? I am doing the same operation on the arrays and they are equal in the beginning as shown by the output. Please let me know if I am doing something stupid here.

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


I wrote a code for keeping record of indices even after sorting but it is showing me null pointer exception.I read other threads on same topic but still couldn't find.  import java.io.*; import java.util.*;  public class Solution { class Order{     public int index;     public int sum;      public void setIndex(int index){         this.index = index;     }     public void setSum(int sum){         this.sum = sum;     }     public int getSum(){         return this.sum;     }     public int getIndex(){         return this.index;     } } public static void main(String[] args) {     /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */     Scanner sc  = new Scanner(System.in);     int N = sc.nextInt();     Order array[] = new Order[N];     int index = 0;     int sum = 0;     while(index<N){         int input1 = sc.nextInt();         int input2 = sc.nextInt();         //line 32         array[index].setIndex(index);         array[index].setSum(input1+input2);         index++;     }     ArrayList<Order> list = new ArrayList<Order>(Arrays.asList(array));      Collections.sort(list, new Comparator<Order>(){         @Override         public int compare(Order o1, Order o2){             return(Integer.compare(o1.getSum(), o2.getSum()));         }     });      System.out.println(list);  } }   error is like this :  Exception in thread "main" java.lang.NullPointerException at Solution.main(Solution.java:32)   I am passing i, still null pointer why?

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


My opponent has two . He taps them both and said he gains 4 life. But I believe he couldn't use the second one with only two of those cards, because cohort said you need another untapped ally

Say I have a Zombie token, , and  on the battlefield. Can I sacrifice the Zombie token to activate both the Altar's and Seer's abilities?  Similarly, if I have one card in hand, and  and  on the battlefield can I discard the one card to both of their abilities?  If I have a  with 3 charge counters can I activate both of its abilities by tapping it to add a counter, and tapping it to remove 3 counters and destroy a permanent without untapping it in between?


I am new to linear algebra and am trying to find the motivation behind defining it in such a way and need for defining it.  To study $2$-D,$3$-D space we have geometry, so why do we need linear algebra then?  Why did they choose the exact properties which a vector space should have? I haven't found any satisfactory answer. The text books directly starts with the theory.   Can anyone explain please?  Edit: "Why we study linear algebra?" is different from my question. That question need the applications of linear algebra, I already know that and there are many source to answer that question. What I need is background of introduction to linear algebra, not only the history, also the motivation behind choosing the properties that need to be satisfied to be a vector space - why not extra why not less? Will taking extra or less condition give something which is not very useful? Please explain it.

Simply as the title says. I've done some research, but still haven't arrived at an answer I am satisfied with. I know the answer varies in different fields, but in general, why would someone study linear algebra?


I'm a new user here, and I wanted to post a question in Math.SE, but whenever I try to post a question I get a message saying I can only post 50 question in 30 day period. But, I haven't even started posting.

I have only asked 2 questions ever; when I now try to ask a question, it says that I have exceeeded the limit of 50 questions/30 days.  What's going on? How can I fix it?


gksudo seeming to be somehow depreciated since 2017 as I see on the , is there an environment and version agnostic best practice allowing to use gedit as root?  (excluding vim, nano or tee: the use case being a GUI amendment of sources.list for instance)  My researchs brought me these proposals, are they equivalent or to be rejected :   pkexec env DISPLAY=$DISPLAY XAUTHORITY=$XAUTHORITY gedit gedit admin:///path/to/document sudo -i gedit sudo -H gedit   Any other ?

I have always recommended pressing ALT+F2 and typing for example gksu nautilus or gksudo nautilus both are equivalent; to run graphical programs with root privileges.  However, I have just installed raring on a test system and this no longer works.  gksu and gksudo are not installed as part of a default raring install; though they are in the repositories. In 12.04 at least gksudo was just a symbolic link to gksu  The reasons I have always done this are because while it is often safe to use sudo under some circumstances it can cause problems with graphical applications because gksu has you running the program as root while with sudo you are running as yourself but with elevated privileges.  This can mean you inadvertently change the owner of critical system files.  This can cause problems.  This reasoning is explained better here:         Why was command removed from a fresh install and what should we be using instead?


I have a problem understanding access modifiers in Java.   public: can be used anywhere. private: can only be used inside the same class. protected: can only be used in subclasses.   I saw many examples and tried but I couldn't understand. I know only the definition. Please any one help me one this give me more examples.  What kind of programs would use private?  What kind of programs would use protected?  What kind of programs would use public?

In Java, are there clear rules on when to use each of access modifiers, namely the default (package private), public, protected and private, while making class and interface and dealing with inheritance?


Source: p 287,   (2010 2 ed) by Henle, Garfield, Tymoczko.     [1.] Predicate is the reason we started on deductions. In Sentential, remember, we can verify that an argument is valid by using truth tables or the short-cut method. With Predicate, we have no such tool. We can show that an argument is invalid if we exhibit a universe in which the premises are true and the conclusion is false, but (until now) we have had no means of showing that an argument in Predicate is valid.    In the 2 Logic textbooks  read (the above and ), each exercise on deductions (e.g. the following) divulges the conclusion of an argument (whether or not valid). But without computers, for a given collection of > 10 long convoluted premises: What if the conclusion were concealed or tacit? How can you determine it yourself?   I am assuming that you must at least conjecture the conclusion, before attempting (dis)proof?

Source: p 287,   (2010 2 ed) by Henle, Garfield, Tymoczko.     Predicate is the reason we started on deductions. In Sentential, remember, we can verify that an argument is valid by using truth tables or the short-cut method. With Predicate, we have no such tool. We can show that an argument is invalid if we exhibit a universe in which the premises are true and the conclusion is false, but (until now) we have had no means of showing that an argument in Predicate is valid.    In the 2 Logic textbooks  read (the above and ), each exercise on deductions (e.g. the following) divulges the (in)validity of the argument, and so enables you to know instantly what to do. But without computers, for arguments with > 10 long, convoluted premises: what if the (in)validity were concealed or tacit?   Per the above, I already know that a Valid Argument can be proven only with Deduction, and an Invalid Argument disproven with a Counterexample. But before 1. writing a Deduction or 2. finding a counterexample, you must have conjectured the argument, respectively, 1. valid and 2. invalid (Otherwise, how would you know to write a Deduction or find a counterexample?!?) So how would you conjecture (in)validity before doing the work?


I recently just lost some time figuring out a bug in my code which was caused by a typo: if (a=b)  instead of: if (a==b)  I was wondering if there is any particular case you would want to assign a value to a variable in a if statement, or if not, why doesn't the compiler throw a warning or an error?

In many languages assignments are legal in conditions. I never understood the reason behind this. Why would you write:  if (var1 = var2) {   ... }   instead of:  var1 = var2; if (var1) {   ... }


Sorry if this is a dumb question but I really haven't been able to find what I'm looking for. Maybe my search terms weren't right.  So there is currently  with the package ttf-mscorefonts-installer, which is fixed in the version 3.6 of the package, which is  but not backported to Ubuntu. Apparently, one workaround for the issue is to use this version instead of the older version available in Ubuntu.  However, even if I was able to find the package listed on packages.debian.org, I couldn't find a way to install it! All that I could download from that webpage is the source file of the package. And I don't think I should directly add debian to my /etc/apt/source.list since that would make me install all other Debian packages as well.  How do I install this one single package?    EDIT: Apparently some people can't read. I mentioned explicitly in my question that the reason why I asked is that I couldn't find the package file on the page, only the source files. Now after reading the answer, I found the package file available for download at the bottom of the webpage, which was totally non-apparent at first sight.

I am an maintainer for a lot of computers in my town running ubuntu 12.04 and 14.04 with mate desktop, this is to help people just having a computer that just works :), and i cannot make them all do terminal work, hense having a .deb install they can download from dropbox via facebook annonce to them will be much better.  So... i want to create a .deb file that does:  apt-get install compiz compiz-plugins compiz-plugins-extra compizconfig-settings-manager -y   and makes the config file in ~/.config/compiz-1/compizconfig/Default.ini so everything works, i will however advice them to start of by ALT + F2 _ compiz --replace to see if everything works ok.  But how do it do this?, i tried apt-get install in control but of course this does not work as it can't start a different install process while instilling this .deb...  this is how i have tried so far...  #!/bin/sh apt-get install compiz compiz-plugins compiz-plugins-extra compizconfig-settings-manager -y mkdir ~/.config/compiz-1 mkdir ~/.config/compiz-1/compizconfig echo "[ezoom] s0_zoom_in_button = <Super>Button4 s0_zoom_out_button = <Super>Button5  [core] s0_active_plugins = core;composite;opengl;compiztoolbox;decor;wall;resize;regex;imgpng;snap;commands;mousepoll;place;grid;move;animation;scale;ezoom;staticswitcher; s0_toggle_window_maximized_key = Disabled  [switcher] s0_focus_on_switch = true s0_icon_only = true s0_mipmap = false  [decor]  [commands] s0_run_command0_key = <Control><Alt>t s0_command0 = mate-terminal s0_command1 = mate-panel --run-dialog s0_run_command1_key = <Alt>F2 s0_command2 = mate-screenshot s0_run_command2_key = Print  [gnomecompat]  [resize] s0_mode = 2" > ~/.config/compiz-1/compizconfig/Default.ini


There was a cartoon/animation where there were 3 main characters and there was this green gem/rock thing that they used to summon creatures. The cartoon started with a kid who received a necklace from his grandfather and there was a green gem in the middle. Then when he was running during a race he was magically sucked into the rock.

What is the name of the anime TV show where a boy can summon beasts with crystals/gems. It was on SABC 2. There was also a boy that could summon a purple turtle . I think the gems were blue, green, and red.


I've tried updating java, updating drivers and such and every time I press connect or load a server in Minecraft 1.7.9, it crashes back to the profile selector and launcher. Here's the error file:    It was too large to post here, so it's hosted there. If you have any idea what's wrong, let me know, all suggestions are appreciated, thanks!

Similar to  on the bugs in Minecraft, I would like a complete list of what error codes exist in Minecraft and how they occur, as well as how they can be resolved.


We all know how to add two completely differently fractions, say we have fractions: -  $\frac{a}{b}$ and $\frac{c}{d}$  We know that: -   $$\frac{a}{b} + \frac{c}{d} = \frac{ad + cb}{bd} $$  Suppose (hypothetically) we add the aforementioned fractions in a completely different way, say: -  $$\frac{a}{b} + \frac{c}{d} = \frac{a + c}{b + d} $$  We get a unique fraction $\frac{a + c}{b + d} $ whose value will always be in between the fractions $\frac{a}{b}$ and $\frac{c}{d}$.  My question is: -  Can someone give me the proof (mathematically) that the statement given below will be always true: -  $$\frac{a}{b} < \frac{a + c}{b + d} < \frac{c}{d}$$   (where we assume that $\frac{a}{b} < \frac{c}{d}$)

We were trying to come up with an easy way to generate a rational number in between two existing rational numbers with a fairly low numerator and denominator (the way we were doing this earlier was to find the average of the two rationals, but that results in a denominator of up to $c * d$. Does this inequality hold for all values of $a, b, c, d$?


Can we start to use Ubuntu, into the main administrator (Root) account, without to have to enter the password?  I know it is intended for security reasons, but... Please! I'm just a church musician and I don't have any kind of "Top Secret" and/or hidden material into this device. Also, I'm the only one which uses this PC, so...  Do I really need that "password way" to enter to my PC?  Whatever, if there is a way to "jump" the password, Please! Let me know!  The screen I get from the "Users & Groups" system configuration menu is:

I want user foo to auto-login using LightDM (which has been used by Ubuntu since version 11.10). How would I do that?


Currently this code creates an empty at a defined position and have used parent to get an object, in this case a cube to be in that position. However the newly created cube states its position as the origin rather than its actual position. How would I get the cube to display its actual position which would be the same as the empty?  import bpy from mathutils import Matrix, Vector  context = bpy.context scale = 0.01   x, y, z, l, m, n, p, q, r = -500, 200, 1000, 1, 0, 0, 0, 0, -1  y_axis = Vector((l, m, n)) z_axis = Vector((p, q, r))  x_axis = y_axis.cross(z_axis).normalized()  M = Matrix((x_axis, y_axis, z_axis)).transposed()  M = M.to_4x4()  M.translation = scale * Vector((x, y, z))  print(M) print(x_axis, y_axis, z_axis) bpy.ops.object.empty_add() mt = context.object mt.empty_display_type = 'ARROWS' empty = bpy.context.object mt.matrix_world = M  bpy.ops.mesh.primitive_cube_add() cube = bpy.context.object cube.parent = empty

How to add an empty object with python using bpy and not using any ops? My code so far is doing this:  bpy.ops.object.empty_add(type='PLAIN_AXES',radius=RADIUS,location=loc)   For normal object like mesh or lamp there is object_data created using normal bpy.data.object.new calls, but for empties it seems that this method does not exist. So is this possible to avoid using the operators? The reason I'm asking is because when I add an empty using bpy.ops it changes the active object, etc. causing the script to be more bloated with unnecessary code lines.


Hello i've tried to sync my ipod shuffle (latest gen) for 2 hours now...  I've tried banshee (I can put music on my device but not listening to it, "use itunes blablabla"), I've tried gtkpod (not launching), Floola (no ipod connected).  How can I proceed ?

What ubuntu applications provide support? (guides, how to's, status) Also, specifically, details on support for syncing music to iPhone's and iPod's with the latest OS version:   Can you sync music to apple devices using >iOS4? (iPhone & iPod) What applications allow you to do this and how? (guides, how to's, status)    What has already been established is:   Apple does not support Linux and has no plans to.  provides some support, however it currently does not support music/video synchronization with devices >iOS4. Go to  and scroll to the section titled "" to see if your device version is supported.


How do I use blender's built in HDRI's? I can see their effect in the viewport and I like it, but when I render, it only uses the other lights I have manually added. I have circled where I am getting the HDRI from. Thanks for any help!

Blender 2.8 contains a number of HDRi's in it by default for the LookDev. I'd like to know how to use them in final renders (EEVEE or Cycles), because quite frankly they appear fantastic.


Let $\alpha ,\beta ,\delta$ be ordinals such that $\alpha < \beta$, prove that there is $\delta \leq \beta$ such that $\alpha+\delta = \beta$ ? I know that if $\beta$ is cardinal then we can take $\delta=\beta$.

I'm trying to prove the statement in the title, a.e existence of ordinal substraction. I think it can be done with transfinite induction, but do any of you have a better/easier way?  thanks


$x$, $y$ and $z$ are all sides of a triangle. Prove that $(x+y-z)(x-y+z)(-x+y+z)\leq xyz$.  Equality occurs when all sides are the same length.  I don't know how to prove that the left side is always less or equal though.   Any help is much appreciated!

I have tried the arithmetic-geometric inequality on $(-a+b+c)(a-b+c)(a+b-c)$ which gives   $$(-a+b+c)(a-b+c)(a+b-c) \leq \left(\frac{a+b+c}{3}\right)^3$$   and on $abc$ which gives   $$abc \leq \left(\frac{a+b+c}{3}\right)^3.$$   Since both inequalities have the same righthand side, I have tried to deduce something about the lefthand sides, but to no avail. Can somebody help me, please? I am sure it is something simple I have missed.


I have a pdf file that is 1.1MB of size but I need upload 400kb of that file. Please tell me how to resize the file to get an output of 400kb.

I have a 72.9MB PDF file that I need to shrink into under 500KB.  The file was a JPEG image that I had scanned, and then converted to pdf.


I just stumbled upon this interesting  about "how to automatically draw tree diagrams of prime factorization with LaTeX" and it rang a bell.  I 'd like to create a command that displays the conversion of an integer value into a bits string (which otherwise is a tedious operation to do "by hand") to use when preparing the exams of FOundation of Computer Science. This command needs 2 parameters, the integer to convert (213, for instance) and the desired number of bits for the result. The command should also be able to convert negative values by using . The following pictures for values 137 (basic problem), -136 (negative problem) and -17 (problem requiring an 8 bits solution) should help you understand what kind of result I would like to get.  As a plus, I would like to introduce two variables to hold the min and max value allowed so that I can get the translation of a random integer value in [min, max] if I call the above command omitting the integer value. One could do the same with the number of desired bits and introduce a variable to hold an increment (4, for instance) so that it generates results with 4 bits and if a number requires 5 bits, for example, it automatically returns a solution that uses 8 bits. Not to mention that with an additional parameter one could convert to octal, hexadecimal, etc.  The problem is that I don't understand Tikz and I have no idea how to make LaTeX do maths! I read  with interest, but I still miss too many things. Can someone help please? Thanks in advance!

I am teaching how to convert from one base to another base, however, I can't find a way to do something like this:    I know little about Tikz, the only thing I have been able to produce is a simple square with a couple of lines over it, so I don't even know where to start. Any suggestions? I don't mind typing all the numbers, what I want to do is to automatize the process of creating the lines.


I entered the Schengen area on March 25 and before the 90-day period expired I applied for a visitor's residenced permit that allowed me 90 extra days. If I go to the UK before August 23 for a week and come back, will they see it as a new 180-day period since I actually entered on March 25 or does the fact that I got those extra 90 days with a visitor residence permit change the 180-day period rule?

My SO and I are currently staying in France under the country's visa long séjour, essentially a 1-year visitor visa. If we return to Europe after leaving when the visa expires we would naturally be covered by the Schengen visa for 90 days, which also begins the 180-day period. How do the rules for these two visas interact? For example, if we applied for another long séjour to begin at the end of our 90-day Schengen visa, does the Schengen period reset 90 days within the long séjour period? Will the French authorities frown on having visa types overlap like this? Our goal is to travel for around 2.5 years in Europe and then return home. We're American and can prove means and lodging for the entire period.


C drive shows 1.8 gb free of 50gb on Windows 8 but when I select all the files(hidden files included) and check the property it shows 42.7gb. What could be the problem and what could be the possible solution?

My Vista 64 installation has drive C, a 150 GB hard drive.  I also has a 1.5 TB drive D.  My C drive has 12.3 GB free.  I don't know what's using up all the space.  There's almost 83 GB unaccounted for!!!  As per  question and  question, I downloaded  and .  WinDirStat, once I found the right options, tells me there's 82.9 GB of .  SpaceMonger, which has a particularly nice display of the data, tells me there's 82.3 GB "Unscanned", with 2 unscannable folders.  Where do I turn now?  Both tools roughly agree there's a large amount of data on my drive, but neither seem to be able to tell me what.  I've tried the standard approach; disk cleanup, remove hibernation file, set the virtual memory to the D drive instead of the C drive.


I'm currently learning Java and I had a question regarding some code that we say in class today, I was wondering if anybody could tell me why the following code outputs 5 and 33 as opposed to just two 33's.  Aren't we assigning the value of d2 to d1 in the modify function?  public class AClass { Date d1 = new Date (5L); Date d2 = new Date (33L); void modify ( Date x, Date y) {     x=y; } public static void main (String[] args) {     new AClass(); } AClass () {     modify(d1,d2);     System.out.println(d1.getTime());     System.out.println(d2.getTime()); }   }

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


The BBC News article  says:  How does the new system work? Electromagnets generate a force. Scrap-yards use them on cranes to lift and move large metal objects, such as old cars. The pull of the electromagnet, the force it exerts, is directly related to the amount of electrical current going through its coils. There is, therefore, a direct relationship between electricity and weight. So, in principle, scientists can define a kilogram, or any other weight, in terms of the amount of electricity needed to counteract the weight (gravitational force acting on a mass). Here's the tricky part There is a quantity that relates weight to electrical current, called Planck's constant - named after the German physicist Max Planck and denoted by the symbol h. But h is an incredibly small number and to measure it, the research scientist Dr Bryan Kibble built a super-accurate set of scales. The Kibble balance, as it has become known, has an electromagnet that pulls down on one side of the scales and a weight - say, a kilogram - on the other. The electrical current going through the electromagnet is increased until the two sides are perfectly balanced. By measuring the current running through the electromagnet to incredible precision, the researchers are able to calculate h to an accuracy of 0.000001%. This breakthrough has paved the way for Le Grand K to be deposed by "die kleine h".  I don't understand the importance of Planck's constant to the use of the Kibble balance in new definition of the kilogram, and the way a Kibble balance is portrayed in the article suggests a kilogram-force rather than a kilogram, since the product $GM_{Earth}$ would be needed in the relationship between the force of the electromagnet on one side of the balance, and the gravitational force on the kilogram mass on the other. I'm assuming that the left side measures the force of one winding upon another in series, rather than a slug of permeable iron. This  touches on this topic but here a more specific answer about the balance itself will be appreciated. This  mentions that local acceleration is indeed part of the measurement and can be addressed to a high degree of precision(?) However it doesn't explain how. Here I'm looking for an answer that gives a practical explanation how this will be done, rather than just being convinced that it could be done in principle.

The metrology world is currently in the middle of overhauling the definitions of the SI units to reflect the recent technological advances that enable us to get much more precise values for the fundamental constants of nature than were possible when the SI was drawn up. This has already happened to the second and the meter, which are defined in terms of a caesium transition and the speed of light, and it is being extended to the other units. Thus, in the new system, known as the ,     four of the SI base units, namely the kilogram, the ampere, the kelvin and the mole, will be redefined in terms of invariants of nature; the new definitions will be based on fixed numerical values of the Planck constant ($h$), the elementary charge ($e$), the Boltzmann constant ($k$), and the Avogadro constant ($N_A$), respectively.   The  gives more details, but it stops short of describing the recommended mises en pratique. For example, for the kilogram, the definition goes     The SI unit of mass, the kilogram         The kilogram, symbol kg, is the SI unit of mass; its magnitude is set by fixing the numerical value of the Planck constant to be exactly 6.626 069 57 10−34 when it is expressed in the SI unit for action J s = kg m2 s-1.         Thus we have the exact relation h = 6.626 069 57 10−34 kg m2 s-1 = 6.626 069 57 10−34 J s. Inverting this equation gives an exact expression for the kilogram in terms of the three defining constants $h$, $\Delta \nu$(133Cs)hfs and $c$:   $$ \mathrm{kg} =\left(\frac{h}{6.626 069 57\times10^{−34}}\right)\mathrm{m}^{2}\:\mathrm s^{-1} =1.475521\ldots\times 10^{40}\frac{h \Delta \nu\left(^{133}\mathrm{Cs}\right)_\mathrm{hfs}}{c^2} $$   The Planck constant is a constant of nature, whose value may be expressed as    the product of a number and the unit joule second, where J s = kg m2 s-1. The effect of this definition is to define the unit kg m2 s-1 (the unit of both the physical quantities action and angular momentum), and thus together with the definitions of the second and the metre this leads to a definition of the unit of mass expressed in terms of the value of the Planck constant $h$.      Note that macroscopic masses can be measured in terms of $h$, using the    Josephson and quantum-Hall effects together with the watt balance apparatus,    or in terms of the mass of a silicon atom, which is accurately known in terms    of $h$ using the x-ray crystal density approach.   However, the brochure is pretty scant as to what the specific realizations through watt balances actually imply in terms of a route from measured physical quantities to values of fundamental constants or to inferred masses. For the specific case of the watt balance, for example, the physical constants at play are much more naturally the  and  constants, $K_J=2e/h$ and $R_K=h/e^2$, if I understand correctly, so there is some re-shuffling of experimental results to be done.  The SI brochure is similarly vague for the other three base unit / fundamental constant pairs.  This brings me, then, to my specific questions. For each of these four base unit / fundamental constant pairs,   what are the proposed experimental realizations, what are the basics of their operation, and what physical effects do they rely on? what other fundamental constants are used to go from experimentally measured values to inferred parameters? (i.e. the meter depends on the second. Does the kilogram depend on the value of the electric charge?) what specific natural constants are measured by the experiment, and how are they reshuffled to obtain final results?   Additionally, what is the dependency tree between the different definitions of the base units? What units depend on what others, either directly or indirectly?


I have a CSV file that i want to enter into a table in my database which is present on a remote server. But presently I don't have access to temp folder so I cannot copy my file on that folder. Is there a way I can upload file from any random folder onto the database?  This is my command in sql server:  load data local  infile 'C:/Users/trainee_aiyer/Downloads/cash_ord.csv' into table cm_ord fields terminated by ',' enclosed by '"' lines terminated by '\n';   and my file path is this:  C:\Users\trainee_aiyer\Downloads\cash_ord.csv   I switched '\' to '/' as the prior was causing syntax errors. but I get an error saying   ERROR 2 (HY000): File 'C:/Users/trainee_aiyer/cash_ord.csv' not found (Errcode: 2 "No such file or directory")

Can we directly load a CSV file ( which is on the local system) on MYSQL DB ( which is installed on the Remote server ) ?  'load data infile into table name' command can only be used for loading in local system only.


A little hard to reproduce, but here's what happens:   A question is closed which has an answer (might need to have only one answer) That answer is edited, [an edit has been made to this post, click to reload] appears Clicking that message makes the close reason disappear   Here's a video:   At first I though "Holy crap, that was reopened fast", then I reloaded the whole page and the close message was back. In fact, I think this bug has been around for quite some time.

I've come across a small issue which occurs when a question has been closed but the question itself or one of its answers are being edited.  Steps to reproduce:   Visit a closed question. (even closed years ago)   In a different tab or browser, edit the question or one of its answers. "an edit has been made to this post; click to load" message will appear above the edited post in the first tab/browser, click it. The .question-status div becomes hidden, which includes the closed notice below a question and, for a duplicate-closed question, the list of duplicates above the question body. This gives the appearance that the question is no longer closed (until you refresh).   Some screenshots:                I know it isn't common/important but it did confuse me when looking at a particularly bad question - I thought it had been reopened.   Is this an intentional feature? If so, what was the thinking behind it?    Another example  Before    After


According to dictionaries, A collection agency, also known as a debt collector, is a business that pursues payments of debts owed by individuals or businesses.  But I have seen in movies that criminal organizations ( Mafias) hire some obnoxious men as ( illegal) debt-collectors whose job is to collect the payments by force and violently, if necessary!  I'd like to know if there is any slang word, term , phrase or idiom among those Mafias members for calling these "debt-collectors" or not!   PS:  1-I have found a British English word "bumbailiff" but it refers to officers whose job was collecting debts,in the past;  so I'm sure I cannot use it for those men hired by Mafias as debt-collectors!   2-In the duplicate question, Morteza is looking for the "debt-collector", but I am looking for its slang equivalent! So please open my question!

There are times when you have received a check from somebody, but there is no money (or not enough money) in their account to cash it. Then you have to resort to asking someone (criminal or something) to tackle the problem and hopefully get the money (or part of it) one way or another.  Is there a word to refer to such a person (criminal)?


I am returning to the US via Amsterdam. I have a US advance parole document. Do I need a transit visa to transit through Amsterdam? Their website mentions US resident permits but does not talk about advance parole.

I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows:  Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland


Can I downgrade my iOS to 7.x? I need to do it for app testing.

I'm trying to downgrade my iPhone from the current iOS to an older one, as per .  But every time I try, I always receive this error:     The iPhone could not be restored. This device isn't eligible for the requested build.     I have tried many times with and without DFU mode. Any ideas regarding this?


Edit: The  was answered by @James and his solution covers the particular problem presented here.    In  I have exposed the original problem and I have received answer to the points 1, 2 and 4, but not the 3th.  Inspired in the answer given by Carina I started to work in some solution, but it is still not 100% right.  Based on  I have decided to post a sub-question to refine the definitive answer and put it on the original post for the posterity.  The (remaining) problem   To make the sections* and put the labels on they (in the spaces, not the lines), @Carina gave me some good ideas, but I need something a little more advanced, the idea is that those lines continues below the X labels. To get the values for the section separator lines from an external file (as is done with the stacked area plots).   ("sections" are those vertical slices or partitions of the X axis seen in the picture. If X is time, they can be understood as consecutive "periods of time")  The partial answer    \documentclass{standalone} \usepackage{pgfplots} \usepgfplotslibrary{colormaps} \usepackage{filecontents}  \begin{filecontents}{data.txt} Time core1 core2 core3 core4 mem 0 7.847 19.51 18.389 18.943  400.90 1 6.863 64.706 12.871 30  913.50 2 10 88 0 0  1215.19 3 57.576 39 0 0  1691.61 4 0.99 99 0.99 0  1694.64 5 0 40.594 60 0  1698.15 6 0 96.939 3.03 0  1699.55 7 0 50.495 48.515 0  1700.09 8 0.99 53 47 0  1703.00 9 0 28.283 69 3  1696.77 10 31.313 0 0 67.677  1697.30 11 15 84 1.01 2.941  2252.78 12 0 15 14.141 71.717  2249.72 13 31 27 6.931 37  2249.00 14 2 13.725 60.606 28  2248.16 15 9 34.343 41 19  2248.31 16 32 41.414 25.743 0  2250.18 17 26 33.663 20.408 21  2249.89 18 23 13 40 25.253  2249.89 19 47.525 18.182 22 12.121  2249.60 20 34.694 25.253 22.772 16.832  2249.32 21 22 0.99 42.574 37.374  2249.01 22 12.871 24 12.121 56.436  2251.39 23 17.172 15.152 49.02 20.202  2252.57 24 27 5.051 32.653 36  2252.72 \end{filecontents}  \begin{filecontents}{data2.txt} % For now, I'm not using this file steps 0 0.024 10.127 10.143 21.634 24.81 \end{filecontents}  \begin{document}     \begin{tikzpicture}[scale=1]         \begin{axis}[             axis y line=left,             axis x line=bottom,             enlarge x limits=0,             enlarge y limits=0,             width=15cm,             height=8cm,             stack plots=y,             area style,             xlabel={Time},             ylabel={CPU usage},             ymax=500         ]             \foreach \i in {1,...,4}{                 \addplot table [y index=\i]{data.txt} \closedcycle;             }         \end{axis}         \begin{axis}[             axis y line=right,             axis x line=none,             enlarge x limits=0,             enlarge y limits=0,             width=15cm,             height=8cm,             fill=none,             ymax=7600         ]             \addplot[very thick,draw=green] table[y index=5]{data.txt};              % The separators are written manually and there is no label             \draw[black](axis cs:  0.024,0)--(axis cs:  0.024,8000);             \draw[black](axis cs: 10.127,0)--(axis cs: 10.127,8000);             \draw[black](axis cs: 10.143,0)--(axis cs: 10.143,8000);             \draw[black](axis cs: 21.634,0)--(axis cs: 21.634,8000);             \draw[black](axis cs: 24.810,0)--(axis cs: 24.810,8000);         \end{axis}     \end{tikzpicture} \end{document}   Some gimp to show the desired output  (Please notice that the steps 1 and 3 are really short, so they seems like a single line but they are two)    Thanks a lot for your time :)

The problem  I need a chart like this (this was made in Libreoffice + some gimp):    Its caracteristics are bassically:   Some stacked bars (if it is a stacked area, better) with its Y axis at the left. A line with its Y axis at the right. Kind of "sections" in the X axis (as can be seen in the picture). I don't know how are they called. Legend in both Y axis.   I need several of these charts with different values, so it would be nice to make them with the same code but different chartX.dat files.  If you could make a minimal example I would appreciate it a lot.  What I have  Currently I have my csv files like this:     time,   Blue,    Red, Yellow,  Green,  Brown       0,      8,     20,     18,     19,    401       1,      7,     65,     13,     30,    914       2,     10,     88,      0,      0,   1215   And other with the section cuts (always starting with 0 and finishing with the biggest number):  0 3 10 22 24   What I have seen   This , but it is not stacked and do not have the "sections". Here a  chart, but I am having troubles merging them. Haven't seen those "sections"    Thanks for your time.


If, for example, someone casts Fog Cloud, next to the target A and target B when they're fighting each other. If target B would run away from the fight he would cause an Opportunity Attack but when the area is Heavily obstructed (by the Fog Cloud spell) all the targets are counted as Blinded.     Blinded Condition         A blinded creature can’t see and automatically fails any ability check   that requires sight.   Attack rolls against the creature have advantage,   and the creature’s Attack rolls have disadvantage      -     Opportunity Attack:      In a fight, everyone is constantly watching for a chance to strike an   enemy who is fleeing or passing by. Such a strike is called an   opportunity attack. You can make an opportunity attack when a hostile   creature that you can see moves out of your reach. To make the   opportunity attack, you use your reaction to make one melee attack   against the provoking creature. The attack occurs right before the   creature leaves your reach.   If target B tries to leave target A's reach can target A use his Perception to beat target B's stealth? Or is target B is not detected, since target B cannot be seen? Or is target B forced to use Disengage even though he can't be seen?

When a PC is in melee with a creature, casts the basic invisibility spell, and leaves melee, does an NPC get an attack of opportunity?


I got a mac last week and am trying to learn the basics by coding a few projects I came up with. I've been creating a few apps I can place on the dock that automate simple functions that I use often. So far, all my programs have worked by creating a zsh script and getting Automator to 'Run Shell Script', however this particular program isn't fully working, although, if I run my program through terminal, it works perfectly. I'm trying to create a program that can be executed after a YouTube url has been copied into the clipboard. The program takes the url and runs it through 'youtube-dl' and downloads the audio into the Downloads folder. I tried to learn how to do this from Z shell alone, but I was very overwhelmed with it and I decided to use python which I already know. Here's what I'm doing: My Python3 code: import os  url = os.popen("echo `pbpaste`").read() os.system("youtube-dl -f 'bestaudio[ext=m4a]' '"+url+"'")  My zsh file: #!/bin/zsh  cd /Users/admin/Downloads python3 /Users/admin/Documents/Scripts/Automation/ytGetAudio/ytGetAudio.py  I then made it executable with "chmod +x /Users/admin/Documents/Scripts/Automation/ytGetAudio/ytGetAudio.zsh" When I run my program from the terminal, everything works great, and the file is downloaded into Downloads, but when I use Automator to "Run Shell Script" and I get it to run the same zsh script it doesn't download anything. I tested it by creating a pop-up message box in the python script; that worked, so the script is running, but something isn't working because nothing is downloading when I run the '.app' file. Can anyone please help me with this?

I have an Automator workflow and one of the actions is to clone a repository. Here's the code for the 'Run Shell Script' action. The command is run within the Bash shell /bin/bash if that matters:  SOURCEDIR="${3/\/Volumes/}"  cd "$2" REPOURL="bob@somedomain.com:$SOURCEDIR" WORKINGDIR="$1"  # Capture any errors with cloning process in log file git clone "$REPOURL" "$WORKINGDIR" &> ./log.txt  // For debugging echo "exit code: $?" echo "PPID: $PPID"  open .   Now the Automator App runs fine on my machine. The path to git on my machine (A Macbook Pro) is: /usr/bin/git (I believe I installed git on my machine through Xcode)  But on my co-worker's machine (Also a Mac Pro) the Automator App fails. In fact, the output of the log.txt file says: bash: git: command not found   Now on my co-worker's machine the path to git is: usr/local/git/bin, which, yes, is different because he installed git through the Google Git Installer for Mac OS X, but I didn't think it should matter because in the script the git command is not absolute path to the command and further more my co-worker can run git normally from a Bash script but when invoked directly from the Terminal.  So what gives? Why does the automator workflow work for me but not for my co-worker?  There must be something fundamental about Bash or Unix that I'm not understanding here but I'm lost.


I am converting an int to a double by dividing the integers by powers of 10. For integers with 7 or greater digits, it appears that rounding is performed when I cast an int into a double. Why is this happening and how can I avoid this rounding?  #include <iostream> using namespace std;  double add_decimals(int x, int decimal_places) {     double ret = 1.0 * x;     cout << "x= " << x << endl;     cout << "ret before changes= " << ret << endl;     for (int i = 0; i < decimal_places; ++i)     {         ret /= 10;     }     return ret; }  int main()  {     double d = add_decimals(1234566, 2);     cout << "d= " << d << endl; }

In my  I was printing a double using cout that got rounded when I wasn't expecting it.  How can I make cout print a double using full precision?


This has happened a few times and I don't know how to diagnose the issue. Below is the code which is as simple as I can get to reproduce the problem.  The vertical spaces between a lot of the lines is far too large suddenly. Removing something like the title or the description environment suddenly fixes it. I cannot target the problem.  \documentclass{amsart} \usepackage{amsthm} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amssymb}  \newenvironment{problem}[2][Problem]{\begin{trivlist} \item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}  \title{title} \author{author}  \begin{document} \maketitle  \begin{problem}{2.32}     Suppose that $\mu(X)<\infty$. If $f$ and $g$ are complex-valued measurable functions on $X$, define:         \[\rho(f,g) := \int\frac{|f-g|}{1+|f-g|}\,d\mu.\]     Show that $\rho$ is a metric on the space of measurable functions if we identify functions which are equal $\mu$-a.e.. Moreover, $f_n\to f$ with respect to $\rho$ if and only if $f_n\to f$ in measure. \end{problem} \begin{proof}     First we need to show that $\rho(f,g)<\infty$ and that if $f$ and $f'$ are equal $\mu$-a.e., then $\rho(f,g) = \rho(f',g)$. Note that the integrand of $\rho$ is bounded above by 1 and $X$ is of finite measure, thus $\rho(f,g)$ is finite for any $f$ and $g$ (being bounded above by the integral of $\chi_X$). Then note:     \[|f-g| = |f-g| + |f'-f| \geqq |f-g+f'-f| = |f'-g|, \text{ $\mu$-a.e.},\]     and similarly, we can get the opposite inequality by swapping roles of $f$ and $f'$. Thus $|f-g| = |f'-g|$, $\mu$-a.e. and then the well-definedness of $\rho$ follows as the integrands of $\rho(f,g)$ and $\rho(f',g)$ are $\mu$-a.e. equal.  Now to prove that it is a metric:     \begin{description}         \item[Indiscernibility] Note that if $f=g$ $\mu$-a.e., then clearly $|f-g| = 0$ $\mu$-a.e., and hence $\rho(f,g)$ is the integral of a $\mu$-a.e. zero function---hence it is zero. On the other hand, if $\rho(f,g) = 0$, then we know that the integrand (being in $L^+$) is zero, $\mu$-a.e.. Thus $|f-g|$ is zero, $\mu$-a.e. and thus $f=g$ $\mu$-a.e.. Hence:             \[\rho(f,g) = 0 \iff f = g, \mu\text{-a.e.}.\]         \item[Symmetry] Note that $|\cdot-\cdot|$ is symmetric, and thus $\rho$ inherits this symmetry as the integrand is symmetric in $f$ and $g$. It also might be worth mentioning that the integrand is positive, so $\rho\geqq 0$.         \item[$\blacktriangle$-inequality] Note\footnote{Meanwhile also noting that $0\leqq x<y\implies \frac{x}{1+x} < \frac{y}{1+y}$. To deduce this, just take its derivative to note it is increasing.}:             \begin{align*}             \rho(f,h)             &= \int\frac{|f-h|}{1+|f-h|}\,d\mu\\             &= \int\frac{|f-g+g-h|}{1 + |f-g+g-h|}\,d\mu\\             &\leqq \int\frac{|f-g| + |g-h|}{1 + |f-g| + |g-h|}\,d\mu\\             &= \int\frac{|f-g|}{1 + |f-g| + |g-h|}\,d\mu + \int\frac{|g-h|}{1+ |f-g| + |g-h|}\,d\mu\\             &\leqq \int\frac{|f-g|}{1 + |f-g|}\,d\mu + \int\frac{|g-h|}{1+ |f-g|}\,d\mu\\             &= \rho(f,g) + \rho(g,h).             \end{align*}     \end{description} \end{proof} \end{document}   A comparison of before and after commenting out the \maketitle:   Maybe it has something to do with page breaks...?

The report I'm writting features a lot of long, multiple lines equations. To reduce visual polution I've been using an aligned environment nested inside equation. This way (unlike just using an align environment) I get only a single label for all the lines.  The problem is that so many long equations often need to be broken into two pages, otherwise I get lots of blank vertical space in the document. However the aligned environment does not allow the \displaybreak command.  Is there an alternative way to achieve a pagebreak inside an aligned equation?  Here's a sample ofthe equations I'm using  \begin{equation}     \begin{aligned}     ...\\     ...\\  %I need to pagebreak here     ...\\ \end{aligned}\end{equation}


In Java, object reference is used for call by reference and variables are used for call by value.  Here’s an example:  class Foo{     int x;     int y; }     public class CallByRef {     public static void main(String[] args) {                     Foo foo = new Foo();         foo.x=5;         foo.y=10;         System.out.println(foo.x+", "+foo.y);         getFoo(foo);         System.out.println(foo.x+", "+foo.y);     }         static void getFoo(Foo f){         f.x=2;         f=new Foo();         f.x=10;     } }   Output:      5, 10     2, 10   Why this is happend?  x should be 10 as I modified its value with f.x=10  Is it correct that f=new Foo() will create new object in heap and not point to prevoise reference?

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


For lack of a better name, I'm trying to create a decreasing stippling effect like this:   My first inclination was that this could be created in Photoshop with some sort of filter effect. I was thinking along the lines of creating a smart object, applying a filter effect, then using a gradient on the filter mask to decrease the effect. This would allow for the possibility of a curved edged like you see in the image. No dice though, there doesn't seem to be an effect that quite does this.   The problem with searching for this effect is that I don't know what it would even be called. I've seen it implemented all types of posters though, so it seems to be generally used.

See how the image background fades with the black menu bar? I see this effect very often and I like it a lot. I would love a tutorial (either Photoshop or Illustrator) or how-to article but I don´t even know how to search for it.


I have the following task:      Show that in topological space $\partial\partial A \subset \partial A$,   where $\partial A$ denotes the set of boundary points of $A$, that is   $\partial A = \overline{A}\;\setminus\;A^o$, where $\overline{A}$ is   the closure of $A$ and $A^o$ is the set of interior points of $A$.   Give an example of $A$ such that $\partial \partial A \neq \partial  A$.   I tried to solve this but I resulted in equality $\partial \partial A = \partial A$, I'm not sure where I went wrong. Here's what I tried:   By the definition of $\partial A$ we have $\partial A\;\cup A^o = \overline{A}$, that is $A^o$ is the open complement of $\partial A$ in $\overline{A}$. Now  $$\partial \partial A = \overline{\partial A}\;\setminus\; (\partial A)^o = \overline{\partial A}.$$  Now because $\partial A$ is closed in $\overline{A}$ then $\partial A$ is the smallest closed set containing $\partial A$, that is $\overline{\partial A}=\partial A$, so  $$\partial \partial A = \overline{\partial A}=\partial A,$$  that is $\partial \partial A = \partial A$   I know I did a mistake in some point...

The definition of a boundary of a set $S$ in a topological space $X$ is $\text{comp}\{\text{Int}(S) \cup \text{Ext}(S)\}$ (complement of the interior union exterior).  The definition for interior is the set of all interior points.  The definition for interior point of $S$ is if there exists an open neighborhood $N$ of that point such that $N \subset S$.  The definition of neighborhood of a point $x$ is a subset of the topological space $X$ that contains an open set such that $x$ is in that open set.  The definition for exterior of $S$ is $\text{Int}(\text{Comp}(S))$.  So $\text{Bdry}(\text{Bdry}(S)) = \text{comp}\{\text{Int}(\text{comp}\{\text{Int}(S) \cup \text{Ext}(S)\}) \cup \text{Ext}(\text{comp}\{\text{Int}(S) \cup \text{Ext}(S)\})\}$ which I can't make heads or tails of. Is there an easier approach to checking of the boundary of the boundary is a subset of the boundary using these definitions?


I just tried to select a mod message template to compose a mod message. However, since that's basically impossible without a mouse (a complaint for another time), I switched to mobile. However, I got... this:    I can't select a template, and I can't side scroll to get the options in view.

If I attempt to create a Moderator Message ("contact user privately") in my mobile browser (Chrome on Android) for Mi Yodeya, with the new responsive design, the modal that allows me to pick a message template is obscured. It is too wide to display on my screen, I can't change the magnification, and I can only scroll to the right and left a little bit. as a result, when I turn my phone sideways for maximum width, the top-right-most and bottom-left-most views of this modal available to me are:    and    The left portion of the modal, including the radio buttons for selecting a message and much of the message titles, is unviewable.  For my purposes, it would be sufficient to fix this by allowing full left-right scrolling.


Is object serialization backwards compatible from Java8 to Java7? I.e., does the Java serialization specification () guarantee that the following works: I compile class A into a Java8 application, serialize an object of A (into a file, say) and deserialize that object in a Java7 application (compiled with the same version of class A). Could somebody point me to the exact part of the specification which specifically adresses different major versions? If there is none, from what part can I deduce said compatibility? Note: Section 5.1 of the specification is about class version compatibility, but not about Java version compatibility.

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


I was playing around with the Rolle's theorem when I ended up fixing a tricky constraint for a function. Suppose, $f$ is a differentiable function in $[0,1]\to\mathbb R$ such that $f(0)=f(1)$. Now if I set a constraint like $f(x)\neq f(x+1/3)$ for all $x\in(0,2/3)$, then can I find such a function? Since $f(0)=f(1)$, there had to be a point where $f'(x)=0$ in $(0,1)$. Intuitively, I feel that there must be some $x\in(0,2/3)$ such that $f(x)=f(x+1/3)$, as it's many-one. But can someone help me prove this using Rolle's or Lagrange's?

If $f:[0,1] \rightarrow \mathbb{R}$ is a continuous function such that $f(0)=f(1)$, then there exists $ x\in [0,1]$ such that  $f(x) = f(x+\frac{1}{n})$, where $n$ is any natural number.  Let $g(x)=f(x+\frac{1}{n})-f(x)$ on $[0,1-\frac{1}{n}]$. Now, $f$ is continuous function on closed interval.So, it must attain its bounds. Let $m$ be minima at $c_1 \in [0,1]$ and $M$ be maxima at $c_2 \in [0,1]$.  Now if $c_1,c_2 \in [0,1-\frac{1}{n}]$, apply IVT to $g(x)$ on $[c_1,c_2]$.  If $c_1$ or $c_2 \in [0,1-\frac{1}{n}]$, apply IVT to $[c_1,c_1-\frac{1}{n}]$ or  $[c_2,c_2-\frac{1}{n}]$ respectively. If  $c_1,c_2$ both do not belong to $[0,1-\frac{1}{n}]$, then apply IVT to $g$ on $[c_1-\frac{1}{n},c_2-\frac{1}{n}]$.  Is this proof correct? Thanks.