order of execution in an expression with commas in C++

It is my understanding that the term j = i will be executed before ++i in the statement  j = i, ++i;.  Does the C++ standard guarantee that j = i will be executed before ++i in the loop   for (auto i = std::next(begin), j = begin; i!= end; j= i, ++i)?


How can I reconnect to a ssh session after a broken pipe?

So I was running apt-get upgrade on a server when the router decided it had been too long since it last made me angry: It dropped all connection. Moral of the story is to use screen a lot when you're on a bum router.  Anyway, I logged back in and found in htop that the process was still hanging there, still waiting for my Y/n to upgrade (hadn't hit it yet, luckily). Is there any way I can reattach to a session that had been broken off? I ended up just killing it since it wasn't in the middle of package management but it would be great to know for future reference.


Let be $D_n$ the group of symmetries of a regular n-sided polygon. Prove that $D_n$ is generated by a minimum rotation angle and a reflection (about a symmetry axis).  I really do not know how to start . Some help plis


How to resolve multiple 'start of turn' triggers

There exist multiple spells/effects/mechanics that can trigger on the start of a character's turn. How in general should a DM rule the ordering, in cases where the order will matter?  As an example: Alice has been downed. She has 0 hit points and has been making death saving throws for a few turns now. She currently has 2 successes and 2 failures. She is also in the area of effect of a Cloudkill spell, which crucially has the following effect:     When a creature enters the spell's area for the first time on a turn or starts its turn there, that creature must make a Constitution saving throw. The creature takes 5d8 poison damage on a failed save, or half as much damage on a successful one.   At the start of Alice's next turn, one of two things could happen, either:  The death saving throw goes first, in which case she has a straight 50/50 of surviving this situation (for now!) or dying right then and there. If she is lucky and gets her third success, the cloudkill is still a concern, but not a matter of life and death. Worst case she is put back into an 'unstable' state but her death saves are reset, buying her precious more time to be saved or evacuated by her party.   or:  The cloudkill check goes first, she dies instantly. Since no matter how well she does on the save to resist it, at best she still takes half damage, and any amount of damage is enough to permanently kill her whilst sitting on two failed death saves.   So whilst in many cases the order of 'start of turn' effects might not matter, in at least this example we have a case where the permanent death of a character could be drastically effected by the order ruled by the DM.   So how should a DM rule the ordering of such effects?


Question edited after that answer was not matched

Suppose i answered some one's question and after some times OP was change the question body that my answer was not matched with the question. So, in future anyone else visited and found that irrelevant answer and they down-voted my answer.  This downward reputation was unwanted.  Is their any solution regarding this type of situation?


Proving that $\forall x\exists y(x = y)$

How to prove in a formal system (like HFOL) the following formula $\forall x\exists y(x = y)$?  Obviously, we would like to use the axiom $x = x$ and then use a rule for introducing $\exists$, but how do we get $x = y$?


What's different between try_files and rewrite?

I want to redirect all dynamic request to index.php for example my index.php : <?php      echo "hi";  ?>  here is my  nginx configure of php:  location ~ \.php$ {        include snippets/fastcgi-php.conf;        fastcgi_pass 127.0.0.1:9000;   }  when i add  configure  with try_files: location / {        try_files $uri $uri/  /index.php =404; }  it just return raw text  <?php echo "hi"; ?>  and i modify the nginx configure with rewrite  it will return hi properly : location / {          rewrite ^(.*)  /index.php last ;                  }   Question What's different between  try_files and rewrite ? Why the directive try_files do not work as i want ?


When stabilized, will receiving temporary hit points prevent failed Death Save when hit?

Sequence of events:   Arthur has 7 hit points left. Arthur is hit and receives 12 damage. Arthur is becomes unconscious and is dying (0 HP.) Arthur's turn comes around, he rolls a Death Saving Throw and fails. Eleonore applies his medicine kit and stabilize Arthur. Lancelot casts an Enhance Ability spell and gives Arthur 8 temporary hit points.  The Goblin hits Arthur and generate 3 hit points of damage.   When the Goblin generates 3 hit points of damage, will Arthur still be stabilized? Since Arthur still has 5 temporary hit points, I would think that he did not go back to the Dying State. That being said, his HP are still 0 and the rules say:     Damage at 0 Hit Points. If you take any damage while you have 0 hit points, you suffer a death saving throw failure.   And at the same time, the Temporary Hit Points section says:     If you have 0 hit points, receiving temporary hit points doesn’t restore you to consciousness or stabilize you. They can still absorb damage directed at you while you’re in that state, but only true healing can save you.   I'm wondering whether the temporary hit points means we're not exactly at 0 HP in that specific circumstance... How do you interpret the rule on this one?


is a tool to build and manage virtual machines for developers.  It has a  guide that contains iffy-looking suggestions like  $ sudo ln -s /usr/bin/ruby1.8 /usr/bin/ruby  # wtf???   or installing RubyGems from source rather than from Ubuntu packages, and then using gem install to install vagrant itself.  I'm not feeling comfortable just following those instructions.  Is there perhaps a PPA?  Are there, perhaps, alternative tools that are packaged for Ubuntu?


What to do when a question is "attacked" by the comment brigade

So there's a first time question, and yes surprisingly it's not that great.. what to do?   Vote to close,  Attach a snarky comment and get 10 million (exaggeration obviously)  up-votes   Sit back and edit the question (no praise) to try and enable it to get the best answer possible - which actually someone else (unless you're houdini!) will likely get the up-votes for by the time you've finished editing   see:   Q asked, Q downvoted 4 times (so far).. comments have all got huge up-votes, question has 1 close vote (that's why the comments I suppose no really good reason to close or it would be by now?) - Q has been edited 8 times (last by me) - I feel sorry for the question asker now, as I think it's lost...   yes I would now vote to close out of sympathy as people are likely only checking that question to add a snarky up-vote on a comment but really don't have a reason to close, nor can or will they answer.. and that's sad  so what to do if a "newb" q is under attack


How to prevent Command-I/Command-Shift-I from opening Mac Mail when in browser?

When in a browser (Chrome or Safari), the following keyboard shortcut will always bring up a window that says "Welcome To Mail":  Command+Shift+I  I would like to use this shortcut for another purpose.  Is there any way to disable this shortcut?


Generalization of Bessel's correction to higher order models?

Multiplying sample variance (i.e. variance from sample mean) by $\frac{n}{n-1}$ to obtain an unbiased estimate of the population variance (i.e. variance from population mean) is called Bessel's correction. We can think of the "mean" as a one-parameter model of the population and variance as the sum of the square errors (which is also the negative log likelihood in the case of normally distributed error) relative to the estimated model. Bessel's correction makes intuitive sense as a compensation for overfitting the model to the data. After all, the model will always fit a single data point perfectly since it has a single degree of freedom (or in the case of a vector quantity, as many degrees of freedom as the data point itself). So we can say nothing about this model's error until the number of data points exceeds 1. Generalizing this model to a linear (affine) function introduces an additional degree of freedom, allowing it to fit an additional data point (in addition to the first data point) perfectly, as a line can intersect two points. Does it then make sense to apply a correction of $\frac{n}{n-2}$ to account for the greater overfitting? After all, we can say nothing about this model's error until the number of data points exceeds 2. In general, if there are $k$ model parameters and we are interested in the expected square error (from the model's prediction), does it make sense to apply a correction of $\frac{n}{n-k}$ to the sample's square error (from the model's prediction)? Would this by any chance be consistent with one of the "information criteria" (BIC, AIC, ...)? EDIT: To clarify the last sentence: Given a set of $N$ data points $\{(x_i\in \mathbb{R}^n,y_i\in\mathbb{R})\}$ and a set of models $f_j:\mathbb{R}^n\mapsto\mathbb{R}$ let $S_{f_j}=\sum(y_i-f_j(x_i))^2$ be a quantity minimized by $f_j$, which has $M_j$ parameters (i.e. $f_j$ was optimized in a $M_j$-dimensional space. For any predetermined model $f$, we could estimate the distribution of error from the model $(y-f(x))$ as a normal distribution $Normal(0,S_{f}/N)$ and then we can evaluate it with the Bayesian information criterion, Aikake information criterion etc. This way, we can select the best model $f_{j^*}$ from $\{f_j\}$. I'm wondering whether I could reasonably just select the model $f_{j^*}$ that minimizes $S_{f_j}/(N-M_j)$ and whether this selection would be consistent with any of BIC, AIC, etc.


Standardization of variables and collinearity

Collinearity can pose certain problems in various kinds of regression problem. In particular, it can make the parameter estimates have high variance and be unstable.   Various methods have been proposed to deal with this including ridge regression, partial least squares regression, principal components regression, dropping variables and getting more data.   One method that is controversial is standardizing or scaling the independent variables, with various experts saying it is a good (e.g. Garcia) or bad (e.g. Belsley) idea. Belsley's issue seems to be (in non-technical terms) that changing the IVs just pushes the problem under the rug.  But other experts seem not to agree. And the authors tend to get rather heated in defending their own positions.   Back when I did my dissertation (on collinearity diagnostics) I found Belsley's arguments convincing, but that was long ago (I got my degree in 1999).  I'm looking either for expert guidance or for any current review article that is unbiased.


Can an Immediate action be taken after an attack hits but before damage is rolled?

So I intend to take . It takes an immediate action to activate.  I already know questions will come up with my DM when I try to use this ability...  The way I understand the mechanics immediate actions are allowed at any time. So I intend to use Wave Shield once an attack connects and damage dice are to be rolled.  So first off is this correct? I believe it is since immediate actions have no restrictions on when they can be used outside of having already used a swift action or immediate action on your turn, or having used your immediate action for the next turn already!  The second question is slightly more awkward, will this casting of Wave Shield provoke an attack of opportunity? I can't find much on the matter besides   It is practically a sidenote that mentions spells with a cast time of a standard action. Does that mean this spell is immune to attacks of opportunity?


Are there general formula for Reflexive Relation?

I wonder if there is a general formula for Reflexive Relation ?  I wonder how to prove it if there is one.


Imagine that I'm exactly in the middle of two identical masses. So that each of them exerts an identical acceleration on me and in the exact opposite direction. My question is Will these opposite accelerations cancel, or will they split me in half?


How to find $\gcd(a^{2^m}+1,a^{2^n}+1)$ when $m \neq n$?

How to prove the following equality?  For $m\neq n$,  $\gcd(a^{2^m}+1,a^{2^n}+1) = 1 $ if $a$ is an even number  $\gcd(a^{2^m}+1,a^{2^n}+1) = 2 $ if $a$ is an odd number  Thanks in advance.


I want to cut my 8 GB USB key into several partitions to use  for a Windows XP (maybe d before).   I also want to put the  remix pack into it such that it has the second bootable OS. I want to tweak and modify it a little because if I can I want to switch Ubuntu 9.04 to the  version.  How to do it easily?  IMP: in short I want to make a dual-boot USB key with Windows XP SP3 and Ubuntu 8.04.3 LTS.


Showing that the space is normal.(exercise)

I have this exercise:     Let $p: X \rightarrow Y$ be a closed continuous surjective map. Show   that if X is normal, then so is Y. [Hint: If U is an open set   containing $p^{-1}(\{y\})$, show there is a neighborhood W of y such   that $p^{-1}(W)\subset U$.]   my attempt:  If I assume the hint is true. Let A, B be to closed sets disjoint in Y. $p^{-1}(A), p^{-1}(B)$ are two closed sets in X, the are also disjoint by elementary set-theory. Let x be an element of A or B, then the hints says that there is $W_x$, open, such that $p^{-1}(W_x)\subset p^{-1}(A)$, or  $p^{-1}(W_x)\subset p^{-1}(B) $. Now, if $x \in A, x' \in B$, then $W_x \cap W_{x'}=\emptyset$, if not, if y is in both sets, then $p^{-1}(\{y\})$, intersects both $p^{-1}(A)$ and $p^{-1}(B)$, which it can't. Is this solution correct?  But now comes the real problem, and that is proving what the hint told us. So assume that we have a point Y, and that $p^{-1}(\{y\})\subset U$, U open in X. How do I go about in finding the open neighborhood W in Y? I still have not used that p is a closed map, so it seems I should use this.   Can you please help me?


Is it possible to recover original content from an edited image file?

OK possibly a random question here, but one that is relevant to the site and regarding a hot topic nowadays: privacy.  If I load an image file (in my case a PNG photocopy of a document which contains some personal details) into Gimp, and I 'fill' with black (i.e. as if to redact) the areas of the image that contain sensitive information, and I then overwrite the original file, is there any way that the original untouched image can be recovered or gleamed? Such as low level bit analysis or...?  If so what tools and techniques are behind that, and how can I mitigate this? Is it a simple case of not overwriting the original but simply creating a new file with the changes?


So I used Agisoft Photoscan to render a model it output a texture that is mapped to different sections of my model  My example:  I have a bunny's head and body  Texture1 is mapped to the bunnies eyes, head, and ears  I want it so that the bunny's eyes have a glossy shader applied to them WHILE maintaining the original mapped texture (kinda combining the mapped portion of the texture with a glossy shader) while avoiding making the rest of the head and ears glossy as well?


Does the spin of electrons imply a more complex structure than has been observed?

If electrons have no substructure and are considered point particles (according to the Standard Model), then how can they also have intrinsic spin?  It would seem that the fact that they exhibit spin would indicate some further complexity to their structure, even if it may not be readily determined.


How to write test class in decimal number to words?

how to write the Apex test class for decimal numbers to words? how to code coverage in class public String getNumberTOWord(Decimal num) {          Decimal junkVal = num;         Decimal junkValPaisa = junkVal - Math.floor(junkVal);         junkVal = Math.floor(junkVal);         System.debug(junkVal);         //Decimal rounded = junKValPaisa.setScale(2);       //  System.debug(rounded);         String obStr = junkVal.toPlainString();         System.debug(obStr);         String[] numReversed = obStr.split('');         System.debug(numReversed);         String[] actnumber = reverse(numReversed);         System.debug(actnumber);         String firstHalf = convertInWords(numReversed, actnumber);         System.debug(firstHalf);                  Integer tmp = Math.round(junkValPaisa * 100);          junkValPaisa = (Decimal)tmp / 100; System.debug('jj :' + junkValPaisa);         system.debug(junkValPaisa);         String paisaStr = junkValPaisa.toPlainString();         System.debug(paisaStr);                 String secondHalf;         System.debug(secondHalf);         System.debug(paisaStr);        if (paisaStr == '0')                      {             secondHalf = '';                      } else if (paisaStr.length() != 4) {             paisaStr = paisaStr + '0';             paisaStr = paisaStr.substring(2);                          String [] numReversedPaisa = paisaStr.split('');             String[] actnumberPaisa = reverse(numReversedPaisa);             secondHalf = convertInWords(numReversedPaisa, actnumberPaisa);             system.debug('paisaStr:'+paisaStr);             system.debug(secondHalf);         }          System.debug('secondHalf :'+secondHalf);          String SumOFHalves = '';            System.debug('SumOFHalves :'+SumOFHalves);         System.debug('secondHalf :'+secondHalf);         if (secondHalf.length() > 3) {             firstHalf = firstHalf.replace('Only', ' And ');             secondHalf = paisaStr.replace('Only', '/100 ');             SumOFHalves = firstHalf + secondHalf;         } else {             firstHalf = firstHalf.replace('Only', '');             SumOFHalves = firstHalf;         }          // IF amount has any value         if (SumOFHalves.length() > 5) {             return SumOFHalves;         } else {             return '';         }     }


So I understand what a static method or field is, I am just wondering when to use them. That is, when writing code what design lends itself to using static methods and fields.   One common pattern is to use static methods as a static factory, but this could just as easily be done by overloading a constructor. Correct? For example:  var bmp = System.Drawing.Bitmap.LoadFromFile("Image01.jpg");   As for static fields, is creating singelton-objects their best use?


In bash, whenever I try to run a command which is not installed, I get a message which tells that the package is not installed and how to install it. This functionality is provided by installing the Debian/Ubuntu package command-not-found. But in zsh, it only gives the message command not found. So how do I install this feature in zsh?


I have a shapefile of 1241 dam locations in Washington, if I open the attribute table I have only latitude and longitude.  I want to convert this to a raster with counts of the number of dams in each raster cell. I am using QGIS but could also use R.


Determine own domain group memberships XP Professional

This seems like it would be a simple question, but my Google skills have failed me.  When logged into a domain (as a domain user without any admin rights), how can I determine what groups my user account belongs to?


Moving files of specific type/extension from one directory to another?

Have a large folder filled with a large collection of different files.Ideally, I want to shift all the different files into their respective folders; so jpg files into the jpg folder etc.   Original folder : unsorted_files destination folder: jpgfolder I tried  mv /home/tony/Desktop/unsorted_files/*.jpg /home/tony/Desktop/jpgfolder   But got an error "jpgfolder" is not  a directory"


I've choosed to upgrade from Windows 7 to Windows 8. When I started up my computer, I saw GRUB and i could choose between Windows 7 and Edubuntu 12.04. But now, when I start up computer, it's just booting Windows 8! (I haven't formatted or anything like that) Please help me!


Distribution of a ratio of uniforms: What is wrong?

Suppose that  $X$ and $Y$ are two i.i.d. uniform random variables on the interval $[0,1]$  Let $Z=X/Y$, I am finding the cdf of $Z$, i.e. $ \Pr(Z\leq z) $.  Now, I came up with two ways of doing this. One produces a correct answer consistent with the pdf here: , the other does not. Why is the second method wrong?  First Method  $\newcommand{\rd}{\mathrm{d}} \Pr(Z\leq z) = \Pr(X/Y\leq z) = \Pr(X\leq zY) = \int^{1}_{0}\int^{\min(1,zy)}_{0} \rd x \rd y = \int^{1}_{0}\min(1,zy)\ \rd y$ $  = \left\{      \begin{array}{lr}        \int^{1/z}_{0}zy\ \rd y + \int^{1}_{1/z} \rd y& : z > 1\\        \int^{1}_{0}zy\ \rd y & : z \leq 1      \end{array}    \right. $ $  = \left\{      \begin{array}{lr}        1 - \frac{1}{2z} & : z > 1\\        \frac{z}{2} & : z \leq 1      \end{array}    \right. $  This appears correct.  Second Method  $\Pr(X/Y\leq z) = \Pr(X \leq zY\ |\ zY \geq 1)\Pr(zY \geq 1) + \Pr(X \leq zY\ |\ zY < 1)\Pr(zY < 1) $ by total probability  $ = \Pr(X \leq zY\ |\ zY \geq 1)\Pr(Y \geq 1/z) + \Pr(X \leq zY\ |\ zY < 1)\Pr(Y < 1/z)$  Taking $z>1$ yields $ (1)(1-\frac{1}{z}) + (\int^{1/z}_{0}\int^{zy}_{0} \rd x \rd y)(\frac{1}{z}) = 1-\frac{1}{z} + (\int^{1/z}_{0}zy\ \rd y)(\frac{1}{z}) = 1-\frac{1}{z} + \frac{1}{2z^{2}}$  This is already different. Why is this wrong?  Thanks!


How to determine whether a wave is travelling or standing? I have been told that wave function of the form $f(k_1x \pm k_2t)$ is a travelling wave. But then even a standing wave equation $2A \cos \omega t \sin kx$ can be written as superposition of two waves $$A\sin\frac{kx-\omega t}{2} + A\sin\frac{kx+\omega t}{2}$$ This is of the form $f(k_1x \pm k_2t)$ but still not a travelling wave.  In particular is $y=\cos x \sin t \ + \cos 2x \sin 2t$ a travelling wave?


Zero article before the word "part" - what is the particular reason for this?

Please consider the following sentences:   It's part of the life. It's a part of the life.   What is the difference in the meaning between these sentences?   Why are we allowed to omit the article from the first sentence?


Theme Action to hook for one time only function

I am developing a custom theme. After my theme is activated/installed I need to run a one time only function that will set some options. What is the best action to hook for this?  Should I use after_setup_theme? My understanding is that this event/action fires on each page load so I don't think I should use this action correct?  *Ps: is it best to place this code in my functions.php file or somewhere else? (I am using the underscores theme template).


After last update of TeX Live packages this code won't compile:  \documentclass{article}  \usepackage{longtable,tabu} \usepackage{color}  \begin{document}  \begin{longtabu} to \linewidth {llX}     a & b & c\\ \end{longtabu}  \end{document}   I got an error:     Missing } inserted. \end{longtabu}   if I comment out \usepackage{color} everything works. Another strange thing - if I change last column type from X to say l - it also works (even with color package added).


Zariski tangent space and $K[\epsilon]/(\epsilon^2)$

I want to prove that the Zariski tangent space at $x\in X$ ($X$ is an affine scheme) is isomorphic to $Hom_K(X,K[\epsilon]/(\epsilon^2))$ (K is the residue field at $x$). I want to say that  $$Hom_K(\mathfrak{m}_{X,x}/\mathfrak{m}_{X,x}^2,K)\simeq Hom_K(\mathcal{O}_{X,x}/\mathfrak{m}_{X,x}^2,K[\epsilon]/(\epsilon^2))$$ so I need splitting $\mathcal{O}_{X,x}$ into $\mathfrak{m}_{X,x}/\mathfrak{m}_{X,x}^2\oplus K$, and I build this splitting using the exact sequence  $$\mathfrak{m}_{X,x}/\mathfrak{m}_{X,x}^2\rightarrow \mathcal{O}_{X,x}/\mathfrak{m}_{X,x}^2\rightarrow K$$ so I need a splitting map $\sigma:K\rightarrow \mathcal{O}_{X,x}/\mathfrak{m}_{X,x}^2$. How can I do to find $\sigma$?


Is it possible to have a full Ubuntu install on a flash drive?

I am trying to make a full Ubuntu install on my 16 GB flash drive. I currently have a persistent Edubuntu 12.04 LTS on it, but this is the install version, which has an annoying "Try Ubuntu" button, as well as a "Install Ubuntu 12.04 LTS" app in it. Is  this possible?


multiple GUI's inside JSplitPane that are selectable

Just a question mostly!  Using JsplitPane, can you display multiple different GUI's including jext fields, file openers, buttons etc dependant on which button is selected?  Example:  Jsplitpane Left component, 3 buttons, gui1  gui2 and gui3  jspltpane right component,  if gui1 is slected, then display gui1, etc.  Reasoning- I have multiple different programs i wish to compile into one program, preferably using jsplitpane as a means to selecting which tool to use.  code so far: created a basic jsplit pane with left and right components (jpanel)  In left component added multiple buttons with action listeners.  In right component, can add buttons labels etc, but how can i assign those buttons/labels to only display if "gui1 " is pressed, and other buttons/labels if "gui2" is pressed.  Thanks!!  fyi, this code is within a jtabbedpane to avoid confusion. gbcjp4 is for the tabbed pane and gbctsp is for the split pane within.      //Create the tool selection pane.     JPanel toolselectionPane = new JPanel();     toolselectionPane.setLayout(new GridBagLayout());     GridBagConstraints gbctsp = new GridBagConstraints();     gbctsp.insets = new Insets(5, 5, 5, 5);     gbctsp.fill = GridBagConstraints.BOTH;       JScrollPane toolselectionView = new JScrollPane(toolselectionPane);      //Add the scroll panes to a split pane.     JSplitPane tsplitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT);     tsplitPane.setLeftComponent(toolselectionView);     tsplitPane.setRightComponent(toolView);     tsplitPane.setDividerLocation(150);      tsplitPane.setPreferredSize(new Dimension(700, 600));      //Add the split pane     gbcjp4.gridx = 0;     gbcjp4.gridy = 1;     gbcjp4.anchor = GridBagConstraints.EAST;         jp4.add(tsplitPane,gbcjp4);        //LEFT SIDE TOOLS SPLIT PANE      gbctsp.gridx = 0;     gbctsp.gridy = 0;     toolselectionPane.add(SaveEvidencebtn,gbctsp);       gbctsp.gridx = 0;     gbctsp.gridy = 1;     toolselectionPane.add(hashingbtn,gbctsp);      //RIGHT SIDE TOOLS SPLIT PANE     //buttons etc here depending which button is selected.


Proving $\frac{S_n}{n^{1/p}} \to 0$ almost surely implies $E|X_i|^p < \infty$

The following is a execise from Durrett's: Probability: Theory and Examples.     Let $p>0$.  Let $X_i$ be i.i.d random variables such that $EX_i =0$, and define $S_n = \sum_{i=1}^n X_i$. Show that if $\dfrac{S_n}{n^{1/p}}\to 0\,$ almost surely, then $E|X_i|^p < \infty$.   He says it's an easy exercise so I imagine there is a simple trick here.  To start, I know that  $$E|X_i|^p = \int_0^\infty P(|X_i|^p > x)dx = \int_0^\infty P(|X_i| > x^{1/p}) dx \leq 1+ \sum_{n=1}^\infty P(|X_n|>n^{1/p})$$  which I think might be helpful. I also think a contrapositive proof might be best?  Suppose $E|X_i|^p = \infty$. Then this implies $\sum_{n=1}^\infty P(|X_n|>n^{1/p}) = \infty$. Since the $X_i$'s are independent, the second Borel-Cantelli lemma then tells us:  $$P(|X_n|>n^{1/p} \quad i.o) =  1.$$  And I think that this implies $S_n/n^{1/p}$ cannot converge to $0$, since for the above implies $S_n/n^{1/p}>1$ infinitely often. Hence, giving the result by contrapositive.  I'm really not confident with my probability theory. So I want to check my reasoning is correct here.


What makes those three curses unforgivable?

NOTICE: The author of this question does not deem the use of those curses to be forgiveable under any but the most extreme circumstances.  What made the Unforgivable curses such? Is it due to legislation, consensus or otherwise? There are other curses which are equally evil, such as Obliviate  - look what it does to Lockhart - which should also be considered Unforgivable. What about permanently transfiguring someone?  In short, What gives?


Last comma in a list of comma-separated adjectives

"Big, white, mountain goat." "Fast, red, Japanese car"  Should there be a comma before "mountain" and before "Japanese"? Adjectives in a list are separated by commas in English, but somehow this last comma seems wrong to me. I've seen sentences with and without this comma. Can someone clarify this for me?  I apologize if my question is unclear, I'm not a native English speaker. I'd appreciate edits for clarity.


Is Java pass by value in case of objects also?

I have searched a lot and every where found that java is pass by value but still I am not satisfied with the answers. Below is the code. Here if i am passing the object of HashMap then I am getting its updated value while in case of integer it is not like that. What is the difference between these both. How pass by value is working in both cases-  public static void main(String[] args) {     HashMap hm = new HashMap();     System.out.println(hm.size()); //Print 0      operation(hm);     System.out.println(hm.size()); //Print 1 ; Why it's updating the HashMap.      Integer c = new Integer(3);     System.out.println(c); //Print 3      getVal(c);     System.out.println(c); //Print 3: Why it's not updating the integer like HashMap. }  public static void operation(HashMap h) {     h.put(“key”, “java”); }  public static void getVal(Integer x) {     x = x + 2;     System.out.println(x); }


$f(x)=\log{\frac{x}{1+\sqrt{5-x^2}}}$  I have to find the derivative of $f(x)$. Please tell me if my steps are correct.  $\frac{1+\sqrt{5-x^2}}{x}×\frac{1}{\ln 10}×\frac{1+\sqrt{5-x^2}-x×\frac{1}{2\sqrt{5-x^2}}}{(1+\sqrt{5-x^2})^2}×\frac{1}{2\sqrt{5-x^2}}×(-2x)$


Is there a document class as described in this question?

I am writing notes for self-lecture on a computer screen on a daily basis (attending math courses). I never intend to print these notes on paper, so the concept of "pages" is quite annoying ; I am always having issues with page breaks because of my big diagrams and self-made environments. Is it possible to have the equivalent of the article class "without pages"? In other words, the equivalent of  without the "being online" part. I want a file that I can read the entire text just by scrolling without any pages. Does that exist?


Must a reversible engine be a carnot engine?

I have this homework question:  "Show that any reversible engine operating between T1 and T2 is a carnot engine."  I think I have a solution, but it feels very hand-wavy. We know that any process that can be represented as a loop in the PV plane is reversible as the net entropy change will be zero. We must operate between two specifice temperatures, so the loop must comprise of two isotherms a T1 and T2. So the question is what curves join the isotherms. As a heat engine comprises of energy input at constant temperature, there will be no energy change between the isotherms. So the curves connecting the isotherms must be adiabatic curves. So we have a carnot cycle.   Is this sufficient? I don't know why, but I doubt it.


overset text over equal sign in in an Align environment

Look at the following example  \begin{align}      & x \\      \overset{\text{some long explanation}}= & foo \\      & = bar \end{align}   what is the best way to get the equal signs aligned? Now I have seen different solution such as adding \overset{\hphantom{\ţext{some long explanation}}}= to the beginning of every line, but I don't really think that is the best solution. Any better ideas?    UPDATE  I guess what i am actually after is   aligning the first column of the align environment right aligning the equal sign under the overset text right


Matching and aggregating data between two overlapped layers using QGIS

I'd like to know how a vector layer can take and aggregate attributes of a field, of another vector layer which is overlapped. For example, a layer T1 has not overlapped records while on the contrary the layer T2 could have overlapped records. I should have a "NEW" field in T1 with the data of T2, separated with ';' every time T2 records overlaps on T1.    How do I automate this process using QGIS?


OK, so I noticed that on every page load (at least here and on Stack Overflow but guess on any Stack Exchange site) there is request for that external JS file:   () Who are we signalling to? For what purpose?  Seriously now, this JS is generating a pixel aka  but I couldn't find anywhere what Stack Exchange is doing with this information or who can access it. I went through the  and found reference to Google Analytics which is totally fine, but the beacon or  (beacon host) are not mentioned there. This is a sample of the data passed using the beacon:    The marked number is the same on all sites and doesn't change per page so it's either user based or machine based. Can I get some details about this? Update: following  I checked the page source and indeed c2 appears to be the Stack Exchange ID: _comscore.push({ c1: "2", c2: "17440561" });  So from what I see, they just measure amount of page hits, without actually collect anything user or browser related.


In Ubuntu 20.04 Desktop what does "Encrypt the new Ubuntu installation for security" actually encrypt?

When installing Ubuntu 20.04 Desktop with the GUI there is a screen where you can choose "Erase disk and Install Ubuntu" with an "Advanced features..." button. If you click that button, you can select "Use LVM with the new Ubuntu installation" and "Encrypt the new Ubuntu installation for security". What exactly does that encrypt, the boot partition, the Home folder, the entire hard drive or something else?


Null Pointer exception using TreeMap and generics

I'm trying to insert a key of type String and a value of type LinkedList (which itself is of type Sprite) into a TreeMap. However, when my code calls the put() method, it throws a null pointer exception and I cannot figure out why.    Here is my Treemap declaration (I'm using Java 7, so it likes the diamond.  TreeMap<String, LinkedList<Sprite>> paneSprites = new TreeMap<>();   Here is part of my method (the rest does the same thing with other sprites and commenting out the put() method here just throws another exception later on at another put() method.  public void initGUIControls() {     canvas = new RambleOnPanel(this, (RambleOnDataModel)data);     LinkedList<Sprite> spriteList = new LinkedList<>();      //Sprite for Welcome Pane     SpriteType st = new SpriteType(settings.WELCOME_BACKGROUND_TYPE);     BufferedImage img = loadImage(settings.WELCOME_IMAGE_PATH);     st.addState(settings.DEFAULT_STATE, img);     st.addState(settings.INVISIBLE_STATE, img);     int x = 0;     int y = 0;     int vX = 0;     int vY = 0;     Sprite s = new Sprite(st,x,y,vX,vY, settings.DEFAULT_STATE);     spriteList.add(s);     guiButtons.put(st.getSpriteTypeID(), s);      //put sprite types for this pane in the hash map and clear the list     getPaneSprites().put(settings.WELCOME_PANE_TYPE, spriteList);  //EXCEPTION THROWN HERE     spriteList.clear();      //Sprites for Select Account Pane   Also, all Strings used here are instantiated in another class as follows  package ramble_on;  public class Settings { //Game Settings public final String APP_TITLE = "Ramble On!"; public final int FRAME_RATE = 30; public final int GAME_HEIGHT = 700; public final int GAME_WIDTH = 1200;  //Sprite States public final String INVISIBLE_STATE = "INVISIBLE STATE"; public final String  DEFAULT_STATE = "DEFAULT STATE";  //Pane Types public final String WELCOME_PANE_TYPE = "WELCOME PANE TYPE"; public final String SELECT_ACCOUNT_PANE_TYPE = "SELECT ACCOUNT PANE TYPE"; public final String CURRENT_ACCOUNT_PANE_TYPE = "CUTTENT ACCOUNT PANE TYPE";  //Sprite Types public final String WELCOME_BACKGROUND_TYPE = "WELCOME BACKGROUND TYPE"; public final String SELECT_ACCOUNT_BACKGROUND_TYPE = "SELECT ACCOUNT TYPE"; public final String NEW_USER_BUTTON_TYPE = "NEW USER BUTTON TYPE"; public final String CURRENT_ACCOUNT_BACKGROUND_TYPE = "CURRENT ACCOUNT BACKGROUND TYPE"; public final String LARGE_RETURN_BUTTON_TYPE = "LARGE RETURN BUTTON TYPE";  //Sprite Image paths public   final String IMAGES_PATH = "./data/images/";  public final String WELCOME_IMAGE_PATH = IMAGES_PATH + "welcome.png"; public final String SELECT_ACCOUNT_BACKGROUND_IMAGE_PATH = IMAGES_PATH + "selectAccount.png"; public final String NEW_USER_BUTTON_PATH = IMAGES_PATH + "newUser.png"; public final String Current_Account_SCREEN_BACKGROUND_IMAGE_PATH = IMAGES_PATH + "currentAccount.png"; public final String LARGE_RETURN_BUTTON_IMAGE_PATH = IMAGES_PATH + "newUser.png";  }


df -h - Used space + Avail Free space is less than the Total size of /home

As the output of df -h shows here, something is eating up 5GB of free space. So, it's not available to use.   I'm also noticing sometimes that the hard disk gets filled up to 100% sometimes. So, I had to restart the machine or delete some unncessary files. Only noticed these in /home partition. Don't know whether these two are related, but appreciate if anyone can put some insight into this.  $ df -h Filesystem            Size  Used Avail Use% Mounted on /dev/sda8             100G   92G  2.7G  98% /home


Prove the congruence of RSA: $C^d\equiv M\ (\textrm{mod}\ pq)$ still hold even if $gcd(M, pq) > 1$.

Pre-conditions:  Let the public key be $(n, e)$, and $n=pq$, which $p,q$ are large distinct primes. Let $gcd(e, (p-1)(q-1))=1$, and $d$ is the inverse of $e$ modulo $(p-1)(q-1)$.   And let $M$ be the raw message, $M < pq$, and $C$ represents the encrypted message(i.e. $M^e$).    Proof:  Since $M < pq$, and $p, q$ are prime, $gcd(M, pq) > 1$ implies that $gcd(M, p)=p$ or $gcd(M,q)=q$, but not both.  WLOG, consider the case $gcd(M, p)=p$ and $gcd(M, q)=1$. Let $ed=1+k(p-1)(q-1)$, then we have:   $C^d \equiv (M^e)^d \equiv 0\ (\textrm{mod}\ p) \equiv M\ (\textrm{mod}\ p)$ $C^d \equiv (M^e)^d \equiv M\cdot M^{k(p-1)(q-1)} \equiv M\cdot1^{k(p-1)} \equiv M\ (\textrm{mod}\ q)$   Since $gcd(p,q)=1$, $C^d \equiv M\ (\textrm{mod}\ pq)$ by Chinese Remainder Theorem. $\mathbf{Q.E.D.}$    This is an exercise in my text book Discrete Mathematics and it's Application, Rosen, page 305, section 4.6. And I don't have the solution...


characteristic polynomial of the adjacency matrix of a tree

I have read that if $A$ is the adjacency matrix of a tree $T$, then we have that  $$\det(\lambda I - A) = \sum_{k=0}^{\lfloor n/2 \rfloor} (-1)^k N_k(T) \lambda^{n-2k} $$  where $N_k(T)$ is the number of matchings of size $k$ of $T$.  However, I couldn't find a proof. Does anyone know how to do it? Thanks!


Using the Well Ordering Principle to Show that n^3 - n is divisible by 6.

I read the following two sources and I think I understand the structure of proofs involving WOP, but I am stuck on the open-ended part where you prove P(n-1) for the  following problem:    Use the well-ordering principle to show that n^3 - n is divisible by 6.    Any help would be greatly appreciated!   Note: After factoring out (n-1)^3 - (n-1) it took the form of n^3 - 3n^2 + 2n and the only difference between that and n^3 - n is "3n^2 - 3n" which I proved was divisible by 6 via induction. Is there a better way to solve this problem?  Edit: , post is useful however I not supposed to use induction for the main part of the proof.


Upgrading from Ubuntu 18.10 to 19.04 AFTER EOL

I just realized I have 18.10 installed instead of the LTS 18.04 (yes, I am such a noob) because apt repositories have stopped updating. Is there a way to upgrade, given that do-release-upgrade does not work anymore?


Is it convenient to go from Latvia to Russia?

I am in Germany. I want to go in this way: Dresden-Warsaw-Lithuania-Latvia-Moscow-Beijing.   I have to bypass Belarus because I do not want to apply for the visa.   The problem is, is it convenient to go from Latvia to Moscow now? I mean the border crossing.  I travel by bus or train. Actually I have no interest in Lithuania or Latvia at all. I just want to go to Moscow as soon as possible.


How to parse a string which contains spaces as an argument in Bash Script

I have a script like the following:  #!/bin/bash  declare -A aaa  while [ "$1" != "" ]; do         case "$1" in                 -e|--env)                         if [ ! "$2" == "" ] && [ ! "$3" == "" ]; then                         aaa[$2]="$3"                         fi                         shift                         shift                         shift                         ;;                 *)                         echo "Error"                         shift                         ;;         esac  done  for K in "${!aaa[@]}"; do         str="$str --build-arg $K=\"${aaa[$K]}\"" done  #echo $str  ./test_args.sh $str   It is called like:  ./multi_args.sh -e arg1 "Hello Man!" -e arg2 Bye   in the second script test_args.sh, I get the built string str and print the arguments.  test_args.sh:  #!/bin/bash  while [ "$1" != "" ]; do         echo "$1"         shift done   it supposed to printed like this:  arg1 Hello Man! arg2 Bye   but it prints:  arg1 Hello  Man! arg2 Bye


how to animate a cylinder unrolling like carpet / toilet paper

I wish to take a thin rectangle / plane with solidify modifier, roll it into a cylinder and then animate it unrolling. For example, imagine a rolled up carpet or a roll of toilet paper.  The  I've found so far do not do the rolling / unrolling in a physically correct manner. (The coiling action happens in the center and the outer roll diameter stays the same the whole time.)  Is there a simple and easy way to roll/unroll this cylinder back into a flat rectangle? Currently, it's a rectangle with a curve modifier applied.     Let me know if there's anything I can add to clarify what I'm looking for.


How can I insert .tiff figures in a Latex document(PDf latex document). I have tried everyting I found in web but nothing.  Please


Jordan normal form and invertible matrix of generalized eigenvectors proof

Struggling to find a place to start with this proof- just began learning about Jordan normal.  Given a 2-by-2 matrix $A$ and a Jordan normal form matrix $J_{\lambda}$, there exists a matrix $S = [v1, v2]$ s.t. $$S^{-1}AS = J_{\lambda}$$ That is, $J_{\lambda}$ is similar to $A$.  WTS: $$(A - \lambda I)v_{1} = 0 $$ $$(A - \lambda I)v_{2} = v_{1}$$    I was going to try to start with the similarity condition and work into producing the two statements below.  Transform the similarity condition to: $$(A = SJ_{\lambda}S^{-1}) * v_{1}$$  Rewrite our first statement to prove as: $$Av_{1} = \lambda I v_{1}$$   Substitute: $$\lambda I v_{1} = SJ_{\lambda}S^{-1}v_{1}$$  But I've been continually getting stuck.  Tried a few ways other than this.  What intuition am I missing?


asymptotic curve, line of curvature and planar curve

I met a problem to prove or disprove that: a. If a curve is both an asymptotic curve and a line of curvature, then it must be planar. b. If a curve is planar and an asymptotic curve, then it must be a line.  For a, I show that the derivative of the shape operator along the curve is 0 and concluding that it is true, although I am not fully convinced by my argument. However, for b, I am totally off.   This question is different from . The condition here is asymptotic, line of curvature and planar, but not geodesic. Please carefully reading the questions.


reputation change notification not visible

I think it's happening after the SO did their last maintenance yesterday. I am not getting that green notification for reputation change neither that red one.  However the changes are being reflected in the overall reputation and and I can view the reputation change by going to the reputation tab on the profile page, but the notification is not being displayed.  Anyone else having the same issue?  Is it a bug or something?   EDIT:  The comment notifications are being shown its just the reputation bar.  EDIT 2:  my meta reputation is also not updating on my SO accounts page.. It's still showing 113, but on meta it's 135..  Is it the same bug or a different one?


A commutative ring with identity is a field if and only it has no nonzero proper ideals

Obviously, if $F$ is a field, and $I$ is it's nonzero ideal, then it contains an invertible element of $F$(any nonzero element of $F$). Denote this element as $a$. Since $I$ is ideal, $aa^{-1} = 1 \in I$. Hence, $I = F$.  But I'm not sure how to prove that any commutative ring with identity without nonzero proper ideals is a field.


There is a SAN mounted 1TB partition for Mysql backups in our server with version 5.0.45-log. From two days, im seeing the log entries ERROR 1114 (HY000) at line 6308 in file & The table user_analysis is full. The mysqldump is 3.2GB. I assue that it will create an issue while restoring this DB.    1. Can we analyse the Dump / backup inconsistancy without restoring (testing), if so how ?   I can aware that this error is occurring due to one table named user_analysis.    Even a single table error leads to dump / backup incosistancy which leads to restoration failure. In my case daily backup is completing successfully. This issue might also cause due to insufficient space. But i had aroung 82GB free space in the SAN mounted partition. I could also see innoDB free space in the table.    blade_server:master_db> show table status like "user_analysis"\G   *************************** 1. row ***************************                    Name: user_analysis                  Engine: InnoDB                 Version: 10              Row_format: Compact                    Rows: 1312878          Avg_row_length: 33             Data_length: 43581440         Max_data_length: 0            Index_length: 19447808               Data_free: 0          Auto_increment: 1312171             Create_time: 2011-11-25 03:00:41             Update_time: NULL              Check_time: NULL               Collation: utf8_general_ci                Checksum: NULL          Create_options:     Comment: InnoDB free: 13190144 kB; (`user_id`) REFER `master_db/users`(`user_id`)       1 row in set (0.01 sec)        blade_server:master_db> select (13190144) /1024/1024;       +-----------------------+       | (13190144) /1024/1024 |       +-----------------------+       |           12.57910156 |        +-----------------------+       1 row in set (0.00 sec)      Where we had around 12.57 GB InnoDBfree space.   InnoDB is per file :     mysql> show variables like "innodb_data_file_path"\G    *************************** 1. row ***************************       Variable_name: innodb_data_file_path       Value:   ibdata1:1000M;ibdata2:1000M;ibdata3:1000M;ibdata4:1000M;ibdata5:1000M;ibdata6:1000M;ibdata7:1000M;ibdata8:1000M;ibdata9:1000M;ibdata10:1000M;ibdata11:1000M;ibdata12:1000M   2. What could be the root cause to this error ? I dont have any diskspace issues.     Where can we pin point for this error ?   3. Will table is full" triggering in logs due to too low maximum size     for"innodb_data_file_path".


Automatically detect the title of question from link in chat

We know the SE has a useful feature of automatically showing the title of question when a link of question is written in the body of question.  For example: https://meta.stackexchange.com/q/288002 automatically shows   Now, how about implementing or introducing this feature in chat? This will help in making chat discussions easier, faster and effective!    Note that similar  for comments is declined with the reason:     No, because comments are processed on the fly. This means a page with 12 links would incur 12 additional database queries -- every time the page is loaded.   But here the thing is different- Once message is posted, the title of stored is stored permanently as a part of message (i.e no issue with loading every time)  And anyway, we know  is quite different from .


I have this question:   $f(0) = 0$ $f(1) = 1$ $f(n) = f(n-1) + f(n-2)$   help me understand and find $f(n)$.


Proof By induction- with powers $7^{2k}$ and $2^{2k+1}$

For all $k\in\mathbb{N}$, prove that $7^{2k}+ 2^{2k+1}$ is a multiple of $3$.  I've tried this question but I’m unsure whether this is a correct method- shown below Base case $K=1$     So $7^{2}+2^3=57$ Induction step Claim $k+1$ is a multiple of $3$ =$$7^2k+2+2^2k+3$$ =$$7^2*7^2k+2^2*2^2k+1$$ $$=49*7^2k+4*2^2k+1$$ $$=4(7^2k+2^2k+1)$$ $$Let$$ $$m=7^2k+2^2k+1$$ $$=4(3m)+45*7^k$$ $$=3(4m+15*7^k)$$ So p(k+1) is  true. As its a multiple of 3 - the proof holds by induction


I've started testing different DEs for Ubuntu because of the Unity news last week. Some of them use Wayland and I like them, but since sometimes I use xrandr to emulate a higher-than-native resolution with newrez I'm left wondering what the tools would be to achieve this on Wayland.  Any suggestions on how to achieve this?


What's this Error means in Android studio

I change can you help me to see where is wrong because it's the same error log   enter code here   public class MainActivity extends Activity {      WebView mWebView; public ImageButton button01; public ImageButton button02; public class MainActivity extends Activity  {  WebView mWebView; public ImageButton button01;           `` public ImageButton button02;  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(mylayout);     button01 = (ImageButton) findViewById(R.id.Button01);     button02 = (ImageButton) findViewById(R.id.Button02);`enter code here`     button01.setOnClickListener(new ImageButton.OnClickListener(){     public void onClick(View v){  jumpToLayout03();    Intent intent = new Intent();        intent.setClass(MainActivity.this, web.class);        startActivity(intent); }}      public void jumpToLayout03() {        setContentView(activity_main01);    }     });}} enter code here   I change can you help me to see where is wrong because it's the same error log


"An example of you not knowing" or "An example of your not knowing"?

Which of these two forms is grammatically correct?


If the sum of $n$ cubes is zero, then the sum must be no larger than $\frac n3$.

Assume that $a_1,...a_n$ are real numbers and $-1 \leq a_i\leq 1$ for $1\leq i\leq  n$. If $$a_1^3+\ldots +a_n^3=0$$ Then show that $$a_1+a_2+\ldots+a_n\le n/3$$   I just came cross this problem the other day. I totally have no idea how to prove it. Are there any hints about which theorem, principle or method to apply?


Why are binary numbers ordered the way they are?

Counting to 7 in binary looks like this:  0 1 10 11 100 101 110 111  The highest value is always to the left. But would it make more sense to to it like this? Is there a way that this was picked, or was it a random decision?  0 1 01 11 001 101 011 111


Is a creature aware that a Hex or Hunter's Mark spell has been cast on it?

Both spells have a verbal component when casting them, but they can both be cast from 90 feet away, possibly from stealth or while the creature is distracted, so it may not notice the casting.   I'm sure the creature would feel the disadvantage to the chosen ability from Hex (would feel/be clumsier if Dexterity is chosen, or short of breath and tired if Constitution is chosen, etc), but might not know the cause. And would an actual mark appear on the target if Hunter's Mark is cast on it?  Would they maybe need to pass an Arcana check (or passive check, maybe) to discern/notice what's affecting them?


Why aren't all Stack Exchange sites available when flagging a question as off topic?

Possible Duplicate:             It occurs to me, more often than not, that I want to flag a Stack Overflow question to move it to math.stackexchange, or other forums, but this option is not available.  If there were at least a comment or reason textbox in the flag form.


Why is the work done by a rocket engine greater at higher speeds?

From this  by orlp:     If I strap a rocket booster to a rocket in space and fire it for one second, then the work provided is much higher when the rocket is flying fast compared to when the rocket was stationary. In both cases the rocket fires for the same duration but in the former case the rocket travels a much greater distance during this period. What gives?


\expandafter in the definition of vaerbatim

I'm now reading the source code of LaTeX.  In the definition of verbatim environment (\@verbatim, exactly), there is something like  \everypar \expandafter{\the\everypar \unpenalty}   What does this \expandafter do?  I only know that \expandafter can delay expansion like  \expandafter\def\csname test-cmd\endcsname   But what will happen if the token after \expandafter is a }?


If a motherboard doesn't explicitly support a RAM frequency, is still compatible?

For example, my  says this:   Supports DDR3 2133(OC)/1866(OC)/1600/1333/1066 non-ECC, un-buffered memory   Is RAM clocked at 2400 MHz compatible? Will the performance be downgraded or it just won't work?  I found other questions but they were related to the CPU cap at 1600 MHz. This cap is related to the motherboard, specs says 2133(OC) max.


Why is my command throwing a 'data tag parsing failed' error?

I am trying to lock some boxes in a map of mine, and I used this command:   /blockdata 10 4 9 {Lock:Elyiana's Mage Key}   At first it worked, but then when I logged back on the next day it gave me this error message:    Data tag parsing failed: Expected '}' but ''' at: {Lock:Elyiana'<--[HERE]     I don't know why it doesn't like the apostrophe in the key's name. I would change it, but it already worked and locked some other items. My version is 1.12, does anyone have an answer to my problem?


I have a question about calculating the degree of a finite field extension over $\mathbb{Q}$.  This is problem 18 in chapter 1 of Patrick Morandi's Field and Galois Theory. The problem asked to show that $$ \left[ \mathbb{Q}{ \left( \sqrt[4]{2},\sqrt{3} \right):\mathbb{Q} }\right] =8 $$ Here's my work : First, we have $$  \left[ \mathbb{Q} ( \sqrt[4]{2},\sqrt{3}):\mathbb{Q}\right] = \left[ \mathbb{Q}(\sqrt[4]{2},\sqrt{3}) : \mathbb{Q}({\sqrt[4]{2}}) \right] . \left[ \mathbb{Q}{(\sqrt[4]{2})}: \mathbb{Q} \right]$$ It's easy to show that $\left[ \mathbb{Q}{(\sqrt[4]{2})}: \mathbb{Q} \right] =4 $ because the minimal polynomial of $\sqrt[4]{2}$ over $\mathbb{Q}$ is $x^4 -2$. Next, I'm going to show that  $$ \left[ \mathbb{Q}(\sqrt[4]{2},\sqrt{3}) : \mathbb{Q}({\sqrt[4]{2}}) \right] =2$$ Consider the polynomial $f(x) = x^2 -3$. It's monic and $\sqrt{3}$ is a root of $f$, but I'm stuck in proving $\sqrt{3} \notin \mathbb{Q}(\sqrt[4]{2})$ (hence $f$ is irreducible over $\mathbb{Q}(\sqrt[4]{2}))$.  My question is: Is there any proof to show that $\sqrt{3} \notin \mathbb{Q}(\sqrt[4]{2})$ or another way to caculate the degree of this field extension?  Thank you for your help.


Cause of "Session Circular Kernel Context Logger failed to start error in Event Log?

I'm running Windows 7 RTM 32-bit.  I'm getting the following error in my event log every second or so:     Session "Circular Kernel Context   Logger" failed to start with the   following error: 0xC0000035    Source: Kernel-EventTracing Level: Error User: SYSTEM OpCode: Start   Any ideas what would be causing this?


Simple Java programm runs slow on Windows 2008 Server

Why is my simple Java programm runs quickly on my local computer and  too slow on Windows 2008 Server?  Programm code:  public static void main(String[] args) {     long startTime;     long endTime;     long totalTime;      startTime = System.currentTimeMillis();      for (int a=1; a < 100000; a++) {         System.out.println("Checking");      }      endTime   = System.currentTimeMillis();     totalTime = endTime - startTime;     System.out.println("TEST1 time:"+totalTime);      startTime = System.currentTimeMillis();      double sum = 0;      for (int a=1; a < 1000000; a++) {         int input = 100;          for(int counter=1;counter<input;counter++){             sum += Math.pow(-1,counter + 1)/((2*counter) - 1);         }      }      endTime   = System.currentTimeMillis();     totalTime = endTime - startTime;     System.out.println("TEST2 time:"+totalTime+" pi="+sum); }   Local computer output:  Checking Checking Checking Checking TEST1 time:427 TEST2 time:7261 pi=787922.5634628027   Windows server output:  Checking Checking Checking Checking Checking Checking TEST1 time:15688 TEST2 time:25280 pi=787922.5634628027   Local computer hardware and soft: Intel Core (TM) i7-2600 CPU @ 3.40GHz Windows 7 Professional 8G RAM  Server hardware and soft:  Intel Xeon(R) CPU E5-2603 @ 1.60GHz  8G RAM Windows Server 2008 Standart Version 6.0  Both computer and server are free from another processes.  May be I have to apply some parametrs to java vm?


How can I find which command is bound to a given keyboard shortcut?

How can I find which command is bound to a give keyboard shortcut? I remember playing with my keyboard shortcuts recently in different places: System/Preferences/Keyboard Shortcuts, "gnome-keyboard-properties" and Compiz. Is there a central place where all those shortcuts are kept or do I have to remember all the places where I set a keyboard shortcut?


Logically assigning values to polygons starting at top left using ArcGIS Desktop?

I have a layer in which the order of the OBJECTID's is rather random.   How do I assign a new field in the data table that assign's number to each polygon based on it's position on the map?  I'd like to have the top left polygon have number 1 and then increment from left to right, top to bottom.


Idiom for random/arbitatry decision making

Sometimes an entity's (be it a person, company, or a government) predictions/choices/decisions seem to be completely arbitrary (based on no evidence or observation).  A very colorful example of this is . When learning that a bank is going bankrupt, a board of judges or whatever decapitate a chicken, and throws its beheaded body into a pit divided into different areas with actions written on them, such as "Bail out", "Do nothing", "Pay $10000", "Sue", etc. The headless chicken runs around for a while until it finally drops motionless on one of the areas in the pit. The judges' verdict is based on where the dead chicken lands.   In Armenian we have an idiom "մատից հոտ քաշել", which literally means "to smell one's finger". Smelling one's finger, of course, does not give one any useful informations, so basing one's forecasts/choices on the "results" of smelling one's finger is completely random and arbitrary. For example, in Armenian one could say:     You can't trust the weather forecast. I think they simply smell their finger and come up with a prediction.   or     How does he know all this?   He doesn't, he just smelled his finger. (i.e. his claims are based on nothing)   or (in a maths class)     Teacher: Can a rational number raised to the power of an irrational number be a rational number?   Student: Yes.   Teacher: See, you have to prove it, you don't get to just smell your finger and answer yes or no.   Hopefully the South Park example and the մատից հոտ քաշել examples fully convey what situations I am talking about. So what idioms are there in English that can describe the arbitrary decision-making/choices?


Proving continuity for function $f: \mathbb{R^2} \rightarrow \mathbb{R}$ given by $f(x,y) = \frac{xy}{x^2 + y^2}$

I'm trying to show that the function $f: \mathbb{R^2} \rightarrow \mathbb{R}$ given by   $ f(x,y)= \begin{cases} \frac{xy}{x^2+y^2}, \text{ if } (x,y) \neq (0,0) \\ 0 \text{ if } (x,y) = (0,0) \\ \end{cases} $  is continuous along every horizontal and every vertical line. From what I understand, I need to show that for every $x_0, y_0 \in \mathbb{R}$, the functions $g, h: \mathbb{R} \rightarrow {R}$ given by $g(t) = f(x_0, t)$ and $h(t) = f(x_0, t)$ are continuous.   I also need to show that the function is not continuous on (0,0).   From the definition, I understand that $f$ is continuous at $p \in E$ if $\forall \epsilon > 0$, $\exists \delta >0$ such that $\forall x \in E$, $d(x,p) < \delta$ implies $d(f(x), d(p)) < \epsilon$.   Here's what I have so far on trying to prove continuity:     For horizontal line, we can set $y=c$ and so the function gives us $f(x,c) = \frac{xc}{x^2 + c^2}$. Similarly for the vertical line, we have $x=c$ and so $f(c,y) = \frac{cy}{c^2 + y^2}$.    But I'm really confused on how I should prove that the function is continuous along the vertical and horizontal lines.   As for proving not continuous at (0,0), can I just say that the function is not defined on (0,0)?   Help would be much appreciated!


STM32 interrupts and C++ don't go well together

I set up TIM3 to fire an interrupt in my project and it just wouldn't work. I tried everything I could and still couldn't find whats the problem. Then I created a clean project and copy/pasted only the code that sets up TIM3 and interrupts and it magically worked. I literally wasted half a day trying to find what causes the problem and it turns out... interrupts don't like C++.  I wrote my code in C++ because I needed classes in my project so naturally I renamed all my prject .c files to .cpp and also compile with the --cpp directive. Everything worked fine, no problems so far until I decided to use interrupts. So I renamed everything to .c and everything worked, renamed everything back to cpp and it stopped working.  I use Keil uVision5 and my projects are generated with STM32CubeMX (only RCC config).  Anyone had this happen to them? Any workarounds?


How to print out every 50 values from a list?

So I am working on a how to be able to print out 50 values from a list each time, meaning if a list contains a length of 120 values, it should print out first 50, then the second 50 and then the rest 20 in that case but the 120 would be a value of X meaning it could be changing all the time:  so what I have created so far is basically just a simple list  listTest = [1233,12412,12412,34653,78556,23523,1231231,345353,4574574,234524523,24124,34534534,4576445,23523523]  for x in listTest:     print(x)   data = {     "recipients": #List of first 50 then it should loop and take the second 50,                    # then loop again through this request and so on,     "originator": "testing", }  response = requests.post("https://test.com/messages", json=data)   which I just made a simple loop through the list but I have no idea on how to make it work that it should print first 50 values in a list, then the second 50 in a list, then the third 50 in a list etc etc until there is no more values in the list.  So it would be like etc:  print     > list of first [50 values]     > list of second [50 values]     > list of third [50 values]     > list of fourth [24 values]   How can I be able to do that?


For the following example, where we have "\" at the end, the \ and EOL character should be removed.  line 1\ line 2 line 3 line 4\ line 5   Output should be  line 1 line 2 line 3 line 4 line 5   Using vi, I can get above stuff as under: :%s/\//n//g  But when I do it on the terminal is not working. Any suggestions?


I did some research and found it could be hard to style a input type=file. However, I realized youtube has a beautiful button displayed when you want to upload your video to the site. (may need login: ). so basically it allows user to click the button, pick a file, and do the upload. I am not sure how this is implemented instead of using the ugly <input> tag? Or anyone knows any alter good way to make a beautiful file upload interface?


Dense subset of two Banach spaces also dense in the intersection

My question is:  Let $ V $ be a vector space (over $ \mathbb K\in\{\mathbb{R}, \mathbb{C}\} $), $ X,Y\subseteq V $ two subspaces equipped with norms $ \|\cdot\|_X, \|\cdot\|_Y $ such that $ (X,\|\cdot\|_X) $ and $(Y,\|\cdot\|_Y)$ are Banach spaces and $ D\subseteq X\cap Y$. If $ D $ is dense in $ (X,\|\cdot\|_X) $ and $(Y,\|\cdot\|_Y)$, is $ D $ also dense in $ X\cap Y $ equipped with $ \|\cdot\|:=\|\cdot\|_X + \|\cdot\|_Y $?  At first sight, it seemed very clear to me that this should be true. But I even fail to answer the following (possibly) easier question:  Let $ X $ be a vector space over $ \mathbb K $ equipped with two norms $ \|\cdot\|_1, \|\cdot\|_2 $ such that $ (X,\|\cdot\|_1) $ and $(X,\|\cdot\|_1)$ are Banach spaces and $ D\subseteq X$. If $ D $ is dense in $ (X,\|\cdot\|_1) $ and $(X,\|\cdot\|_2)$, is $ D $ also dense in $ X $ equipped with $ \|\cdot\|:=\|\cdot\|_1 + \|\cdot\|_2 $?  The answer is yes, if $ \|\cdot\|_1, \|\cdot\|_2 $ are equivalent, so I tried to think about a counterexample using nonequivalent norms on a specific space and I also found a nice paper about nonisomorphic complete norms () but it didn't helped me so far to construct anything useful for my question.  Thanks for your help!


When I calculate the momentum of something what does the answer mean?

When you calculate momentum e.g  An object moving at 10 m/s that has a mass of 5kg. This object will have a momentum of 50 kg*m/s.  What I don't understand is, what does the 50 kg*m/s mean? Does it mean the stopping power it would take to bring an object to rest? If so, in this case it would be 50 Newtons?


How to reactivate a iPhone 5s which was originally activated from another account (Device already removed from previous iCloud)?

I bought my iPhone 5s about 3 days ago.Once i bought it i activated the phone from one of my friend's AppleID and password , because i needed to check if the phone functions well, before i leave the shop.but then after when i got back home i made a new apple account and used the phone with that account.  But since my phone is activated from my friend's iCloud i logged into account from his appleID and password. then i removed the device from his account. Then i erased the phone then rebooted it and setup a new i phone  with my AppleID and iCloud but still my phone is NOT Activated in my new account??  can someone please help me to activate my phone from my new account????


Linear separability for a sum of kernel functions

Suppose we have 2 kernel functions $K_1(x,y)$ and $K_2(x,y)$. We know, that the dataset ($(x_1,y_1),\ldots,(x_l,y_l),$ $y_i \in \{-1,1\}$ ) is separated with the first one (that is, there are $w,$ $w_0$: $$y_i(K_1(w,x_i)-w_0)>0 $$ for all $i=1,\ldots,l$ ), and not separated with the second kernel function. What we can say about kernel function $K_1(x,y)+K_2(x,y)$ ? How I can show that the same dataset is separated with it?


align text content of tabular cell vertically relative to image in nearby cell

I'm using a slight variation of the solution indicated  to insert a picture of a signature next to the name of the person who signs in a document with the following code:  \documentclass[11pt]{article} \usepackage{lipsum} \usepackage[a4paper]{geometry} \usepackage{graphicx} \vspace{5mm}  \hspace*{\fill} \begin{tabular}{c c} Name Surname & \includegraphics[scale=0.35]{image.pdf}  \end{tabular} \end{document}   which gives the following result   However I would like to align vertically the text of the left column to the top of the image in the right column. I tried all the solution I found here without any success.


Im experimenting with random theme and "new technology" and Im trying to convert whole front-end to pure JS single page application (no page refreshes - like Facebook, Twitter etc) using ,  and  and few other helpers.  How to handle logged-in users? How do I keep track of that? I know that this information is normally handled with cookies. How would one check it via JS?  I could just make an ajax call every time route/url changes and use is_user_logged_in() in server-side but it seems primative. Could I access directly to cookie via JS and check it in browser?     I gave it a long thought if that's off-topic here but it really seems like a very WP specific question Im just experimenting and trying to push it to a new level, please no "this is a bad idea" comments


What is the difference between ‘said’ and ‘told’?

I have confusion about said and told.   It may seem like very small thing, because said and told are synonyms, but I wonder if there are times when one is more appropriate or correct than the other.


How can I query SEDE for tags I've created?

How can I query the  for tags I've created?


I have been using the sklearn RandomForestClassifier to solve a binary classification problem.  For a particular sample prediction, I would like to be able to know how to change the features values to make the prediction change.   E.g. let's say I have an entry with [size = 15, width = 8, height = 13] and the model gives me aprobability = 0.9 to be of class 1. What I would like to be able to say is "change size from 15 to 10" and then your probability=0.1 for example.  Then optimally, what I would like is the smallest "gradient" in the features values to pass from one class to another (or the one that gives the most change in probability).  Maybe I'm wrong, but from what I've read the packages LIME and treeinterpreter do not provide this kind of information.


Is $A = \{ B \subset E: B \text{ countable or } B^c \text{ countable}\}$ a sigma algebra?  I would want someone to verify if my proof below is valid.   a countable union of elements in $A$ is still in $A$   I divided it into three cases, let $(H_j)_{j \in \mathbb{N}} \in A$   All $H_j$ countable, a countable union of countable sets is countable, and it lies in $A$. all $H_{j}^{c}$ countable then $(\cup_{j \in \mathbb{N}} H_j )^c = \cap_{j \in \mathbb{N}} H_{j}^{c} $ countable and it lies in $A$. Either $H_j$ or $H_{j}^{c}$ is countable, then $|(\cup_{j \in \mathbb{N}} H_j)^c| = | \cap_{j \in \mathbb{N}} H_{j}^{c}| = min\{|H_1|, \dots , |H_n|\} \leq |\mathbb{N}|$ countable, and it lies in $A$


When specifying DNS information for a domain (e.g. in the registrar control panel) one can use nameservers which are subdomains of the domain. For example, if I have a domain example.com, I can set nameservers "ns1.example.com 1.1.1.1" and "ns2.example.com 1.1.1.2" (IP-addresses are mandatory). What is the process of resolving the name ns1.example.com?


I was looking at the  and trying this code:  from fractions import Fraction  >>> print("Fraction (0.5):", Fraction(0.5)) Fraction (0.5): 1/2 >>> print("Fraction (0.1):", Fraction(0.1))  Fraction (0.1): 3602879701896397/36028797018963968 >>> print(1/10)  0.1   Looking at the Fraction(0.1) result I thought it was my computer problem, but when I tried it on several computers the results were same.    My question    is there any computational reason to choose these odd numbers 3602879701896397/36028797018963968 instead of 1/10 just like 1/2 as it chosen for Fraction(0.5). more of these exist in python?


I would like to know, in  $1/0.5 =2$ why does $1/0.5$ yield $2$.   I want to know a conceptual explanation, not merely a method how to get the answer.   If you are able to explain this in example using image that would be super helpful!  My understanding is if you divide one whole pizza we get $2$ halves slice of pizzas which is $1/2$. So, $1/0.5 = 2$ mean you will get $2$ whole pizza?


Word to describe one capable of providing necessary things, but prioritize unnecessary things instead and expects help afterward

Example: Someone who purchases clothes, furnishings, trips, home renovations etc. but then pleads with friends or starts gofundme for assistance with pet surgery, car repairs, etc.


public static void main(String[] args){          String buf;      buf = JOptionPane.showInputDialog("1, 2 or 3");      if (buf == 1) {         Begin2();}//if a     if (buf == 2) {         Main.Begin6();}//if b     if (buf == 3) {         Main.Begin7();}//if b }   I have this code, but if cant invoke any of Begin methods...


Is $\lim_{x\rightarrow 0}\sqrt x$ well-defined?

I have a limit, $\sqrt x$, in which I consider only values of $x\in\mathbb{R}$. If I then consider values of $x$ approaching zero, I know that:  $$\lim_{x\rightarrow 0^{-}}\sqrt x$$  does not exist, and that:  $$\lim_{x\rightarrow 0^{+}}\sqrt x$$  does exist, so I can then conclude that the limit does not exist and I understand that, but does this mean that the limit is not well defined as $x$ approaches $0$ as well?   Thanks.


Is Veritaserum used in Wizarding Court to determine if a suspect is guilty or not/telling the truth?  Would there be a general list of questions asked to the truth-serum-affected suspects?


Dyson’s method based on base $3$ number representation (Fake coin finding by weighing problem)

In one book I faced a problem which had a solution with Dyson’s method about which I can't find any info in Google, can you refer me to anything? It is connected to some base $3$ representation of a number. The problem is as follows: We want to find a counterfeit coin among $12$ coins, if it is unknown if the fake coin is lighter or heavier. Using only three weighings, find the fake coin and establish whether it is lighter or heavier than a real one.


Why do I have 0 edit suggestions approved and 0 edit suggestions rejected?

After I reviewed some edits recently, I went back to my history to see how others treated those edits. To my surprise, I had 0 edit suggestions approved and 0 edit suggestions rejected in rejected edits. Example ():    But ~300 short of proper numbers in approved edits:    My total as seen in the bar is 2358, but 1438 + 594 = 2032. I'd guess this might because of skipped edits.


I was browsing my logs on papertail and I saw this.  Jun 03 03:26:01 /USR/SBIN/CRON:  (root) CMD (test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily ))      Jun 03 03:26:04 su:  Successful su for www-data by root      Jun 03 03:26:04 su:  + ??? root:www-data      Jun 03 03:26:04 su:  pam_unix(su:session): session opened for user www-data by (uid=0)      Jun 03 03:26:04 su:  pam_unix(su:session): session closed for user www-data      Jun 03 03:26:04 su:  Successful su for www-data by root      Jun 03 03:26:04 su:  + ??? root:www-data      Jun 03 03:26:04 su:  pam_unix(su:session): session opened for user www-data by (uid=0)      Jun 03 03:26:04 su:  pam_unix(su:session): session closed for user www-data      Jun 03 03:26:04 syslog-ng:  Configuration reload request received, reloading configuration;      Jun 03 03:26:04 syslog-ng:  EOF on control channel, closing connection;      Jun 03 03:26:05 syslog-ng:  Configuration reload request received, reloading configuration;      Jun 03 03:26:05 syslog-ng:  EOF on control channel, closing connection;      Jun 03 03:26:05 CRON:  pam_unix(cron:session): session closed for user root      Jun 03 03:39:01 CRON:  pam_unix(cron:session): session opened for user root by (uid=0)    Isn't it possible breakin attempt? Why is root logged as www-data and syslog-ng reload configuration?  Edit.  Files in /etc/cron.daily  apt  aptitude  bsdmainutils  dpkg  lighttpd  logrotate man-db  passwd  In lighttpd is   #!/bin/sh # Cleanup lighttpd compress cache  cache=/var/cache/lighttpd if test -d "$cache/compress"; then     su -s /bin/sh -c "find $cache/compress -type f -atime +30 -print0  | xargs -0 -r rm" www-data fi if test -d "$cache/uploads"; then     su -s /bin/sh -c "find $cache/uploads -type f -atime +1 -print0 | xargs -0 -r rm" www-data fi


I have a list and I a trying to concatenate 2 items in the list using .join().   Sample data:  l = ['a', 'b', 'c', 'd'] str = ' '.join(l[1:2]) print(str)   The output prints only b but I am expecting to print b c. someone point me what is wrong here


Why redirection operators from windows prompt create text ignoring line break?

I tried to output to a text file using redirection operators > and >> from a java class but it ignores line feed \n from java when the .txt file is opened with the Notepad from windows 10. It's interesting because on the prompt the line feed works just fine and if I use System.out.println("") it works normally in the Notepad.   Class with \n line feed:  class n{      public static void main(String[] args){          System.out.print("This\n");         System.out.print("Should\n");         System.out.print("Be\n");         System.out.print("Separated.\n");       }  }   Class using System.out.println(""):  class ln{      public static void main(String[] args){          System.out.println("This");         System.out.println("Should");         System.out.println("Be");         System.out.println("Separated.");      }  }   Output in the prompt:    Output in text file from class n (n.txt) opened with Notepad:  ThisShouldBeSeparated.   Output in text file from class ln (ln.txt) opened with Notepad:  This Should Be Separated.   These two above should be equal.  I tested with the class n public but it didn't change the result.  I've searched and found about how to echo a line feed, that's not what I want, I want the redirected text file working like the prompt.  One interesting detail is when I paste the text from n.txt in here (writing a question), in the Microsoft Word, Notepad++ or WordPad (or open the file in the programs cited) it "fixed" the error and was equal the result from class ln.  EDIT  I think it's not a duplicate because when I wrote the question I didn't even think about the possible Notepad problem. The title is completely different so I answered my own question for people who didn't think that the problem is the Notepad, like me before, may get an good solution.  If I'm wrong I would be happy to be corrected.


Continous extension of Fibonacci numbers

If we consider the sequence $a_n = (n-1)!$ then the Gamma function $\Gamma(n)$ gives exactly $a_n$ at each positive integer $n$. Let $F_n$ denote $n^{th}$ Fibonacci number. Does there exist a continous function $F(x)$ such that $F(n) = F_n$ at each positive integer $n$? If it exists should it be unique ?


I am trying to write the program that will be given a 2d list with coordinates of points on a grid (ex.[[4, 7], [5, 6], [5, 2]]), and will return all points passed during "walking". We can go diagonal.  def pole(lista):     passed = []   #List with all points passed     before = lista[0]  #list with coordinates before     for i in range(1,len(lista)):         first = [list(range(before[0],lista[i][0]))]   # Lists that should have all points         second = [list(range(before[1],lista[i][1]))]  # passed from point to point          if(len(first) == 1):                  #If we do not go diagonal, one list will only have one number here,             first = [before[0]*len(second)]   # but we need the same number of itmes,         if(len(second) == 1):                 # so we do not get IndexOutOFRange error in next for                second = [before[1]*len(first)]         #print(first,second)         for j in range(len(first)):             passed.append([first[j], second[j]])         before = lista[i]     return passed   We are using the example list as an input. [[4, 7], [5, 6], [5, 2]]  The problem is that the output is wrong and I do not know why:  [[4, 7], [5, 6]]   And the output should be:  [[4,7], [5,6], [5,5], [5,4], [5,3], [5,2]]   I think it is a problem of range function


See a list of my top voted comments? Or another way to track progress on Pundit?

Pundit  Left 10 comments with score of 5 or more   I saw a discussion question that mentioned Pundit, which that stated that , however, something like top voted comments seems to fit in with the rest of stackoverflows feature set, as well as indirectly provide a method to track progress on this badge. Should there be (or is there already) a list of my top voted comments somewhere?


Show that $(A\setminus B) \cup (A\setminus C) = B \Leftrightarrow A=B \wedge (B \cap C) = \emptyset$

I believe there are 3 parts to this.  1) $(A\setminus B) \cup (A\setminus C) = B  \Rightarrow  A=B $  2) $(A\setminus B) \cup (A\setminus C) = B  \Rightarrow (B \cap C) = \emptyset$  3) $A=B \wedge (B \cap C) = \emptyset  \Rightarrow (A\setminus B) \cup (A\setminus C) = B$   I can do the the parts labelled 1 and 3 but cannot show part 2.  Anyone who can explain how you do the 2nd part ie show $(A\setminus B) \cup (A\setminus C) = B  \Rightarrow (B \cap C) = \emptyset$ ?


Decide between Polyglossia and Babel in 2012

Could someone summarize features which are (1) common and (2) different for the  and  packages? I know that babel 3.8 (current version) fails to run for some languages  (eg, Russian) under LuaLaTeX and XeLaTeX (at least it was so 2 years ago). What will be the future of the polyglossia package if babel 3.9 (which is now ) will manage to work with XeLaTeX? Will be any sense to use polyglossia as a replacement of babel in that case?  UPDATE: I am sorry for mixing several questions in one post. Main question was about differences between polyglossia and babel. For example, polyglossia has options specific to some languages.


javascript - get width of element without knowing the ID

I have the following code: <div> <script> // get the width of the parent element </script> </div>  it is possibile to get the width (and the height) of the parent element where the script tag is placed?


Recover initial files after git reset --hard HEAD~

Please help! I've been working between several computers and wanted to keep track of my non-programming schoolwork. I set up an initial repository on Github, initiated that on my local machine, and then proceeded to add all files in my school directory, commit those files, and then attempted to push them to the repository. However, I did not realize how large the GIS files were, so the push kept failing. I wanted to go backward so that I could create a .gitignore file to skip over the large files, and tried to following command to clear out the commit:  git reset --hard HEAD~   I had no clue that this wouldn't just untrack the files, but delete them from my file system. Now I have lost my entire school directory.  Can anyone suggest how to recover any of the files? I can't find an answer elsewhere.   EDIT:  The answer below worked great, here's the result:  D:\Documents\College\Masters\[MyUniversity]>git reflog 99b0b97 (HEAD -> master, origin/master) HEAD@{0}: reset: moving to 99b0b97 99b0b97 (HEAD -> master, origin/master) HEAD@{1}: reset: moving to HEAD~ a291e5a HEAD@{2}: reset: moving to HEAD a291e5a HEAD@{3}: commit: added all files 99b0b97 (HEAD -> master, origin/master) HEAD@{4}: commit (initial): first commit  D:\Documents\College\Masters\[MyUniversity]>git reset --hard a291e5a Updating files:   0% (37/8608)


This question arises from below:  Initially you are given a circle $C_2$ with radius $r=1$. You construct the regualr 3-gon (equilateral triangle) with its incircle as $C_2$, and its circumscribed circle $C_3$. Then use $C_3$ as incircle and repeat this process, so you can construct the regualr $n$-gon with its circumscribed circle $C_n$. Does the limit of the radius of $C_n$ exist as $n\to\infty$ ? If it exists, what is the value?  My attempt  I have worked out that the radius of $C_n$ is  $$r_n=\prod_{i=3}^n\sec\frac{\pi}{i}$$  Since $\lim_{n\to\infty}\sec\frac{\pi}{n}=1$, I concluded that $\lim_{n\to\infty}\frac{r_{n+1}}{r_n}=1$, and the limit of $r_n$ exists. But I cannot find its limiting value. MATHEMATICA says $r_{10^4}\approx8.69574$. Do you have any suggestions on how to proceed?  Thank you in advanced!


Can I get my security token without having to reset it?

I need to get a user's security token but there are other things currently using it so I don't really want to reset it. Is there any way to retrieve this without having to reset it?


Which one is correct: "my little brother" or "my smaller brother"?

If I'm 18 and my brother is 15, is he my little brother and I'm his elder brother? Or he is my smaller brother and I'm his bigger one?  Any clarifications?


Seeing that Defense Against the Dark Arts is a crucial subject, both in Harry's life as well as a part of the school-going wizard's curriculum, it must be in the hands of a good professor.   Is it known who Minerva McGonagall appointed as DADA prof. once she was made Headmistress. Was it someone we know or was it just a random powerful wizard. Is there any information about this available?


Addition of two algebraic integer numbers

Is the addition of two algebraic integer numbers also algebraic?   I, guess it is, but i can't prove it. I wonder if multiplication of them is also algebraic.


Why do I have to log in again to https://data.stackexchange.com/ frequently?

I stay logged in on https://*.stackexchange.com for weeks except on , where I have to log in again every few days. Why?


How I can refer multiple equation in Latex?


Which of these is correct capitalization?        Mrs. Ohana gave me the Bible.   Mrs. Ohana gave me The Bible.


I need to set the specific size and position for objects in Illustrator. For example, I need to set the size to 100 × 50 mm, but Illustrator automatically sets its size to 100.189 × 50.094 mm. Same thing happens with position.


Bartle, Introduction to Real Analysis (2011 4 ed), Ex 14, Section 6.2, p 179.

Let $I$ be an interval and let $I : I \rightarrow \mathbb{R}$ be differentiable on $I$. Show that if the derivative $f'$ is never $0$ on $I$, then either $f'(x) > 0$ for all $x \in I$ or $f' (x) < 0$ for all $x \in I$.  I was thinking to proceed by Darboux's theorem. Is that correct?


My problem is that every time I press "esc" button on my site it refreshed the page to the base root (without me even requesting it to happen). I have no idea what causes that and which event of keyup/keydown is registered.  My question is:  How can I see what events are currently registered on my site so I can track this issue?


I have studied following definitions of equivalent metric spaces.  Two metrics on a set $X$ are said to be equivalent if and only if they induce the same topology on $X$.   1:  Two metrices $d_1$ and $d_2$ in metric space $X$ are equivalent if $d_1(x_n,x_0)\rightarrow 0 $ iff $d_2(x_n,x_0)\rightarrow 0 $.  2: We say that d1 and d2 are equivalent iff there exist positive constants $c$ and $C$ such that $c d_1(x, y)\leq d_2(x, y)\leq Cd_1(x, y)$ for all $x, y \in X$.  My questions are as follows:  Is there any other definition of equivalent metrics? I need a proof of how these conditions are equivalent?  Is there any connection between homeomorphism and equivalence of metric spaces?  What are the common properties shared by equivalent metric spaces?  I am very much confused with this. Quite often I found myself struggling with what definition  should I apply to show the equivalence of given metric spaces. I need help to clear my doubts.  Thanks a lot for helping me


Construct Subgroups of $\mathbb{Z} \times \mathbb{Z}$

How can I construct subgroups of $G \times H$, where $G = H = (\mathbb{Z}, +)$?    I thought that the only subgroups of the integers where the integers times some constant, but then I don't know how to prove that, and even if I did I don't know if that applies to this situation.


Kryptos : K1. What is the origin of the "palimpsest" keyword?

I'm studying the  with its cryptographic puzzles K1 to K4.  I understand that the keyword "palimpsest" was reverse-engineered using the tableau (and brute-force computer processing), but Sanborn always said that all sections could be solved using pencil and paper.   There are theories about the Morse, but I haven't come across a good explanation of how to tease "palimpsest" out of it.  I've been frustrated trying to find this in the Kryptos Yahoo group.  I'm not concerned that it has any "meaning" just whether or not there is any other way to derive the keyword other than brute-force, from e.g. the Morse code.


Elegant way to make a bijection from the set of the complex numbers to the set of the real numbers

Make a bijection that shows $|\mathbb C| = |\mathbb R| $  First I thought of dividing the complex numbers in the real parts and the complex parts and then define a formula that maps those parts to the real numbers. But I don't get anywhere with that. By this I mean that it's not a good enough defined bijection.      Can someone give me a hint on how to do this?    Maybe I need to read more about complex numbers.


This is a short story about a super intelligent child named Star.  She has a friend almost as intelligent.  They discover a way to get to another dimension or universe where similarly gifted people have gone.  Her father hopes to find a way to follow them to protect her.


Sum the area of buildings inside a block (QGIS)

My problem is to get the sum of the area of all buildings inside a block.   There are a layer with the buildings (they contain an block_id to which block they belong and the area) and a layer with all blocks (they have a block_id). I want to sum the areas of all buildings with the same block_id and store this sum in a new column in the block-layer to the block with this block_id. I add an picture to clarify my question and structure of data. There are two blocks. The left on has the block_id = '078060' and the right one block_id = '078070'. Now all my buildings in the left polygon have an attritbute also called block_id with the value '078060'. I want then to sum up all the areas of the buildings in the block and store this value to my block layer.  I thought about calculation this with the field calculator in QGIS. But I don't know how.   The question "" is just a first step to solve my problem, because the calculated sum for the categories (block_id) should be added to a new column in the blocks_layer. I was looking for a possibility to automatically calculate the sum and store it to a new column.


Sun Grid Engine's qmon -- "Cannot convert string..."

I recently tried to run qmon (from Sun Grid Engine job queueing system) and when I do, I get a bunch of warnings that look like this:  Warning: Cannot convert string "intro" to type Pixmap Warning: Cannot convert string "toolbar_job" to type Pixmap Warning: Cannot convert string "toolbar_queue" to type Pixmap Warning: Cannot convert string "toolbar_submit" to type Pixmap Warning: Cannot convert string "toolbar_cplx" to type Pixmap Warning: Cannot convert string "toolbar_host" to type Pixmap Warning: Cannot convert string "toolbar_cluster" to type Pixmap Warning: Cannot convert string "toolbar_sched" to type Pixmap Warning: Cannot convert string "toolbar_calendar" to type Pixmap ...   And then, when the GUI finally appears, all of the icons are replaced by a small dot.  I guess for some reason, the icons cannot be shown.  I tried to look for them in:  /usr/share/gridengine/pixmaps/   and indeed, the *.xpm files are there.  About half a year or so ago, it worked fine.  I guess something happened to my system during an upgrade or update that changed things.  Any ideas on what I should be looking for?  Any log files that could help me?  Thank you!  Ray  PS:  On Ubuntu 13.10.


Ubuntu on VirtualBox very very slow (revisited)

Using Virtualbox 5.0 with Windows 8.1 as host and Ubuntu 14.04.2 as guest. It is extremely slow. I have tried  1) Increasing the RAM size  2) Used multiple processors in Systems->Processor tab (have IntelCore i7 processor)  3) Enabled 3D Acceleration in Display->Screen tab  4) Increased the video memory   5) Tried enabling/disabling Extended features in the settings  6) Also tried Ubuntu-15.04 (behavior remains the same)  Here's () from a user some time back.  The system is still slow...is there anything to be done in the BIOS? and i doubt it, as my windows is pretty fast. Any help appreciated! (Thanks!)


Does being in the area of effect of a spell at the time of casting count as "entering"?  For example when casting Web:     Each creature that starts its turn in the webs or that enters them during its turn must make a Dexterity saving throw. On a failed save, the creature is Restrained as long as it remains in the webs or until it breaks free.   If it did not count it would imply that if you cast web on someone next to you, you would not get the chance to move the same turn with the benefit of them being restrained.


Registration in Russia on a 90 days business visa

I want to ask about registration within seven days in each new city in Russia. I know there are a lot of people asking this question before but I really need more data about this. I would love to provide a bit more information about myself than ask for questions.  I’m from Taiwan. I really hope someone who has traveled in Russia more than two weeks could answer my question with your experiences.  So basically next year I am planning to live in Russia 90 days with business visa, and I don’t have friends over there. I basically want to live nearby Couchsurfing, or directly ask people if I could stay with them, because I don’t have that much of money to living hotel or live in hostel  every day.  I was living in Vladivostok Russia for 30 days but when I left customs nothing happened -- customs never checked my registration. On top of that I googled, and a lot of people seemed to have the same situation as me: no one checked their ”within 7 days registration”; on the other hand, there are a bunch of people who are claiming that I must register or otherwise I will have big trouble.  Here are my questions:   Since I’m planning to live in different cities by hitchhiking, how can I register ”registration within 7 days stuff?” Has anyone been stopped by police and had their registration checked?  Has anyone been traveling on a buiness visa like me as well? How is the process of registration? Is it complicated and time consuming? No one talk about the valid time for the registration; for example, if I was planning to stay in whatever which city for 10 days, but then I stayed for 20 days, do I need to register again? Even though I stay in the same city?   Or is it so that with registration in a city, it doesn’t matter how many days you stay? It's just a proof that I’m actually visiting there?


I have a desktop and a laptop that are stuck in Ubuntu 15.04 Any time I try to install or update any software, either through Software Centre, Package Manager or apt-get, it crashes out with a bunch of error messages once it starts trying to download files from the Ubuntu repositories. I've tried all different methods to try to manually upgrade the system files from version 15.04. But all updater or upgrader processes all crash once they start trying to download from the repositories. Nothing works to let me download the packages I need or upgrade the system. Any way I can fix it manually or do I need to get like a Ubuntu 18 installation CD and reinstall the whole system?


I love my MacBook (2008, aluminum, Intel processor with the low-end nVidia chipset). I don't like running Windows. I don't want a Windows Bootcamp partition, because I found I never used it. (I really only used it for Oblivion, and even then stopped eventually because I enjoyed it more on the XBox, and hated the reboot-into-Windows process.)  I'm using WINE to run Fallout and Fallout 2, with great success. I also have the Steam client, which I've used to get Portal and a second copy of Civ IV (+ addons, mostly so I didn't need the DVD with me).  What I want to know is, can I buy a Windows game from the Steam client for the Mac, and then run it via WINE? If so, do I need to take any special precautions? (For instance, my current winecfg emulates a 640x480 desktop to enable Fallout and Fallout 2.)


My mac terminal prompt is:   wbk-er-10-132-118-162:~ johnjara$   I did echo $PS1 and got \h:\W \u\$, which would be the hostname: the basename of $PWD, my username, respectively. My  computer name in System Preferences > Sharing is Copper's Macbook Pro.   So what is \h here for my Mac if not computer name? How do I change it?   Also, why my IP address would be there in hostname?


Bring a "human factor" into review audit composition/selection

Some people are complaining about the automatically generated audits. They are based on close reasons and apparently are a little controversial :-)          etc   I propose that for "good reviewers" (definition TBD) an extra UI component be added to let the reviewer suggest this as an audit item. Possibly:   Reject and add as audit button (Close and add as audit, etc) checkbox next to Reject, Close, etc checkbox on the Reject reason, Close reason etc dialog (could get messy, and some actions such as Reopen don't involve a subsequent dialog) dialog after rejecting, closing, Recommend Deletion, etc   Further, after passing or failing an audit, we could ask "good reviewers" "was this a good audit"? Bad audits, whether auto-generated or human suggested, could be removed from use if enough "good reviewers" identified them as such.  Now, what's a good reviewer? I don't want to judge only on behaviour in the review queue. I think flagging well is a good sign. So is editing - maybe an edit-related badge? And yes, some number of reviews would be good. Maybe some ratio of pass to fail on review audits. But not JUST what we do in the queues.  (I first suggested this in my answer to  but I'm bringing it up as a feature request of its own and to apply to all the queues.)


What connotation do these words describing "someone who straightforwardly expresses their" opinion have?

The adjective ones I have heard recently are    forward straightforward forthcoming frank   I was wondering if each of them has positive, negative or neutral meaning?  What are other similar terms that are used for positive, neutral and negative intention?


How to evaluate $ \int \sec^3x \, \mathrm{d}x$?

How to evaluate $ \int \sec^3x \, \mathrm{d}x$ ?  I tried integration by parts and then I got $$\int \sec^3x \, \mathrm{d}x=\sec x \tan x - \int\sec x \tan^2 x \, \mathrm{d}x.$$ Now I'm stuck solving $\int\sec x \tan^2 x \, \mathrm{d}x$? How to solve that and how to solve my initial question? What is the smartest way solving $ \int \sec^3x \, \mathrm{d}x$?


As you can see i added three torus shapes to the center of the model but i would like to cut out the insides of those torus to leave circles in them how can i do this?


I've inherited a document library with some documents stored in folders within folders within folders etc  I've tried creating a library view with "Show all items without folders"  but I get the following error  This view cannot be displayed because it exceeds the list view threshold (5000 items) enforced by the administrator.    I need to move some of the documents to a new library. There is no metadata that would help show only the documents I need other than "Created By". I tried adding this as a filter to the view but I still get the same error  Any suggestions?


Is password confirmation necessary on a Change Password dialog?

On one hand there is no need to ask for password confirmation because it is annoying. If I made a mistake when confirming my password I'll need retype my very complex password again. There is also a button that can show/hide the password so I don't need retype it in order to confirm it.   However, some users don't use the password show/hide button and the 'forgotten password' option will be pain for them.  Twitter removed the password confirmation from registration but left the dual confirmation in place for changing password. Is this right approach?