What balancing method can I apply to an imbalanced data set?

I'm trying to solve  from the UCI database repository. Unfortunately (or fortunately), I've noticed that my dataset is imbalanced. I've structured the data as 5 classes, according to the final mark reached by the pupil, like so:   If student gets a mark from 0 to 7 => class 1 [FAIL(E)] If student gets a mark from 8 to 9 => class 2 [SUFFICIENT(D)] If student gets a mark from 10 to 11 => class 3 [GOOD(C)] If student gets a mark from 12 to 15 => class 4 [NOTABLE(B)] If student gets a mark from 16 to 19 => class 5 [OUTSTANDING(A)]   My problem is that, as I said, data are imbalanced, so I want to balance it.  I've thought about applying some kind of undersampling method, but my dataset has only 649 instances so I think removing some of them is not the best idea. Then I thought about doing some oversampling, in order to replicate some of the minority class examples and then get classes balanced, but I'm still unsure if that could work.   I would be very grateful if you could give me a hand with this. Its the first time I face a real problem with imbalanced data.


How to free up storage space associated with "System" on macbook pro mojave OS?

The laptop apparently is taking up ~87 gigabytes of space for system. I don't know how to dig into the details of why and to look into possibly freeing up some of that space as that seems rather excessive. I asked a friend and they only had ~11gb associated with system.  I did have a hard time upgrading from high sierra to mojave, and had to do a reboot into safe mode then hit some buttons on the app store to install mojave which eventually seemed to work.


when tried to edit .bashrc file The command could not be located because '/usr/bin' is not included in the PATH environment variable

When i tried to edit .bashrc file I am getting the above error how to solve this. when i gave  $ echo $PATH /home/vijay/usr/bin:PATH:/bin   is displayed Steps in detail would help


As far as I can tell, consumer interchangeable-lens cameras are all categorized as single-lens reflex, rangefinder, or mirrorless. I feel like I never see these classifications used, though, for fixed-lens cameras like the Leica Q, Sony RX1, or Fujifilm X100T. Are all such cameras mirrorless or do some of them use a mirror and prism?


Visual Studio 2010: How to generate documentation out of code comments?

I wrote some comments for my code. Now how can I generate a documentation or something similar with Visual Studio 2010?


Can random forests use cross validation?

As cross validation may help limit overfitting, I think this tech can also help random forest to avoid overfitting sometime. But it is little weird using cross validation because random forests are already an ensemble method using random samples when training.


A simple proof for $\prod_{i=1}^d a_i+\prod_{i=1}^d b_i \le \prod_{i=1}^d (a_i^d+b_i^d)^{1/d}$?

Let $a_1,\dots,a_d,b_1,\dots,b_d$ be positive real numbers. Then $$ \prod_{i=1}^d a_i+\prod_{i=1}^d b_i \le \prod_{i=1}^d (a_i^d+b_i^d)^{1/d}$$ and equality holds if and only if $\frac{a_i}{a_j}=\frac{b_i}{b_j}$.     Is there a nice proof for this fact? Is there some geometric interpretation?   I know a proof based on an application of Holder's inequality which seems rather miraculous to me. The idea is to define $f_i:\{0,1\} \to \mathbb{R}$, by $f_i(0)=a_i,f_i(1)=b_i$, and to endow the domain $\{0,1\}$ with the counting measure. The generalized Holder's inequality then states that  $$\prod_{i=1}^d a_i+\prod_{i=1}^d b_i\le\|  \prod_{i=1}^d f_i\|_1 \leq \prod_{i=1}^d \|f_i\|_d=\prod_{i=1}^d (a_i^d+b_i^d)^{1/d}$$  and equality holds if and only if $\frac{f_i}{f_j}$ is constant, i.e. $\frac{a_i}{a_j}=\frac{b_i}{b_j}$. Somehow, I feel that it's weird to use an "abstract" measure-theoretic inequality, applied to such a degenerate case (finite measure space with the counting  measure).     Are there other, "more elementary" proofs?   Even the case where $a_i=c$ are constant does not seem trivial to me: i.e. why  $$ c^d+\prod_{i=1}^d b_i \le \prod_{i=1}^d (c^d+b_i^d)^{1/d}$$ and equality holds if and only if $b_1=b_2=\dots=b_d$.  I tried using the generalized Young's inequality for multiple products, which states that $$ \prod_{i=1}^d a_i \le \frac{\sum_i {a_i^d}}{d}.$$ (This is in fact the AM-GM inequality in disguise.)  This implies  $$ \prod_{i=1}^d a_i+\prod_{i=1}^d b_i \le \frac{\sum_i {a_i^d}+{b_i^d}}{d} \ge \prod_{i=1}^d (a_i^d+b_i^d)^{1/d}$$  but the direction of the last inequality (also by AM-GM) is opposite to the one we would like to have.  Of course, we can always mimic the (inductive) proof of the generalized Holder inequality, but this does not seem enlightening to me.


Would it be possible for latex to generate the text of my latex document to a pdf consisting of one single giant, very long page. This pdf would not be for printing, but just for online viewing.


Let's assume that there is nothing in the universe except Earth. If the Earth rotates on its axis as it does, then would we experience the effects of rotational motion like centrifugal force and Coriolis force?  The meaning of my question is: is Earth rotating relative to space?


Is there a command that outputs ONLY the packages explicitly installed by the user? (ubuntu/debian)

I have tried searching for this but there seems to be no command that can output a list of packages (ideally in Ubuntu) that I have installed, not including any dependencies.


Does TTY always get used when we open any terminal?

I have been trying to understand how the TTY device driver works on a Linux machine for a few days now and still can't wrap my head around the idea.  When we open a terminal to ssh to a server, I understand most likely it will use pseudo-tty; that acts like a TTY in the terminal and processes the commands typed.  Since it uses a pseudo type tty, under the hood does it still use the tty technology to send out commands to the console?  In layman's terms, is the TTY always used in sending out commands to the console regardless of the terminal used? Is it the main driver for all things terminal?  I understand the tty character device that handles input and output and bunch of things that sends out signals to master/slave. I also know that a tty was used in the olden days. Is it still used today when opening our terminal regarding of OS/program used?  My knowledge is all over the place. I have very limited Linux knowledge. Would love to have a layman's explanation on how TTY works in today's Linux distributions.


What is the point in using the structure "To be + past simple verb"? Example: "For the first time in connection with the plagues, God specifically noted the discrimination to be made—Israel would be untouched."


A paper I'm reading says that the algebraic closure of $\mathbb{Q}_p$ is not complete, by using for example the Baire theorem. Wikipedia says the Baire theorem says that a complete metric space is a Baire space (meaning a countable intersection of dense open sets remains dense). I don't see how this can be used to show the claim that $\overline{\mathbb{Q}_p}$ is not complete. Any other argument is also welcome.


What method can I use to solve$\int \frac {dx} {e^x - 1}$

I have been staring at this question for about half an hour now.  EDIT  If you were wondering, this is not a dupe of the question "How to solve $\int \frac {dx} {e^x + 1}$ "


Does the order of columns matter in PCA for the results? Jumpy factor loadings?

I have six UK inflation time series, starting from Jan 1990 and ending in June 2019. These series as standardized on an expanding window and subsequently forward filled. I use these series to run a PCA on an expanding window size (initial data has 1300 observations). I expand this window size every time by one day. For all these inflation series I compute the factor loading at every date (day) t. I plot the Factor loadings below:    However, now I re-run the analysis and I switch the third column (time series 3) with the first column (time series 1). My factor loadings now behave totally different and I obtain jumpy sign reversals now. I show the new factor loadings below:    The time series stay the same. They start at the same time and do not contain missing values / NA's or whatever. I only switch the order of the columns.  My questions: 1) Why does the order of the columns impact the PCA Factor Loadings results? 2) How do I deal with such jumps in factor loadings and, especially, avoid them?  I am using the princomp command in R to determine the factor loadings. I hope someone can help me out, because I am really stuck on this matter.


App permission management is running notification

Is there any option to get rid of those not useful, permament notifications on Android 5.1, in particular App permission management is running  They are just taking space and focus, are not helpful to the user at all.    Edit: please note that I'm asking about the notification messages, not the icons.


How do I insert a space every four characters in a long line?

I've got a long line that I want to insert a space every 4 characters, on a single lone line of solid text to make it easier to read, what's the simplest way to do this? also I should be able to input the line from a pipe. e.g.  echo "foobarbazblargblurg" | <some command here>   gives  foob arba zbla rgbl urg


Can I add an exterior outlet by tapping an adjacent interior outlet?

Can I tap in a outlet not being used that is behind a bed and add a outlet behind it outside? Using it for a electric bbq grill. The grill specs are: 110 volt, 60hz, 275w, 5 amp service.


Short story, published before 1976.  Humanity has spread along the circumference of the galaxy (apparently avoiding the core), and diversified.  The main characters are a married couple of a hairless race. They charter(?) a ship to follow evidence of alien intelligence (humanity having never found any before). The captain of the ship is of The Men, an all-male society who celebrate nature by always going naked.  (One of the couple says, “I'd swear they sort their genes for hairiness. Did you notice he actually has eyebrows?”)  We track down the aliens and make contact.  They like sulfur in their air, but upon comparison of biochemistry we find that they are humans too, whose ancestors spread around the galaxy in the other direction.  The two parties then turn their gaze to the Andromeda Galaxy, remarking that it's a forbidding project but we must do it.


How to export textures applied to a mesh's faces in a texture atlas

Is there a way one can combine all textures that are applied to a mesh's faces in a texture atlas in blender and export said atlas as .png alongside an .obj for example?  If not, is there a way one can map textures of a texture atlas to a mesh's faces in blender? (I believe this process might be called 'uv mapping', but how does one apply images to the unwrapped 2d image?)  Here a sample atlas:    Should any of this be possible, do you know of any tutorials that explain the process in detail?


how to prove that any Cauchy sequence in a discrete space  is stationary   Let $(x_n)$ be a cauchy sequence then $$\forall \varepsilon>0, \exists n_0\in \mathbb{N},\forall p,q \geq n_0\Rightarrow \begin{cases} 1\leq \varepsilon, x_p\neq x_q\\ 0\leq \varepsilon,x_p=x_q\end{cases}$$  how to continue?   thank you


How to make random dots in different sizes and spaces between the dots in Illustrator?

I am trying to make something similar to this?  Obviously it's possible to make it manually piece by piece, but I am looking for some kind of automated feature in Illustrator to achieve this?  Is this possible?  Thanks man in advance!


Is there any good textbook or notes on graph theory for undergraduate student?

I am looking for such textbook or notes. Thanks in advance for sharing links or sites or any related questions!


Getting Exception in thread "main" java.lang.NullPointerException after changing my regex

I'm trying to check files within a folder to identify the file names that match my regex. My regex matches to incorrectly named files.   So, for example, I have these files in a folder:  -95F Front Anger BW.jpg     -95F.Front.Anger.C.Micro.jpg     -95F.Front.Fear.C.Micro.jpg     -95F.Front.Frown.BW.jpg   The regex should match the first one because correctly named filenames need to have dots instead of whitespaces.   public static void main(String[] args) {    Pattern patternList = Pattern.compile("^(?!(?:((\\d{1,3}([FM])\\."              + "(Front|Profile|Right)\\.(Anger|Fear|Frown|Smile)\\."              + "(BW\\.Micro|BW|C\\.Micro|C)))|(\\d{1,3}(F|M)\\."              + "(Front|Profile|Right)\\.(Neutral|Smile)\\.(C\\.Micro|C|BW\\"              + ".Micro|BW|HighLight|LowLight|MedLight)\\.(BW\\.Micro|BW|C\\"              + ".Micro|C))|(\\d{1,3}(F|M)\\.(Selfie1|Selfie2|StudentID)\\."              + "(C\\.Micro|C|BW\\.Micro|BW)))).*$");      Scanner in = new Scanner(System.in);   System.out.print("Enter base directory: ");   String dir = in.nextLine();    checkFolder(new File(dir), patternList); //EXCEPTION HERE  }  private static void checkFolder(File root, Pattern patternList) {   for(File file : root.listFiles()) //EXCEPTION here         if(file.isFile()){             if(!patternList.matcher(file.getName()).matches())                checkFolder(file, patternList); //EXCEPTION here             else                 System.out.println(file);         }         }


This is a Lemma from N.L. Carothers Real Analysis.  Lemma. An infinite subset $A$ of $\mathbb{N}$ is countable.  Proof. Since $A\ne\emptyset$, there is a smallest element $x_1\in A$. Then $A\backslash\{x_1\}\ne\emptyset$, and there must be a smallest $x_2\in A\backslash\{x_1\}$. By induction we can find $x_1,x_2,\dotsc,x_n,\dotsc\in A$, where $x_n=\min(A\backslash\{x_1,\dotsc,x_{n-1}\})$. Now, suppose that $x\in A\backslash\{x_1,x_2,\dotsc\}\ne\emptyset$. Then the set $\{k:x_k>x\}$ must be nonempty, and hence it has a least element. That is, there is some $n$ with $x_1<x_2<\cdots<x_{n-1}<x<x_n$. But this contradicts the choice of $x_n$.  The part of the proof that I don't understand is that the set $\{k:x_k>x\}$ must be nonempty. Carothers claims that otherwise we would have $x\in A$ and $x<x_1=\min A$. I can't prove that if $\{k:x_k>x\}=\emptyset$ then $x<x_1$.  Help appreciated please.


Dual space of finite dimensional space V has the same dimension

Is there a simple proof showing that $\dim V^*=\dim V$? Where $V^*$ denotes the dual space of a finite dimensional space $V$?


New to Ruby on Rails looking for a phone number validation

I am new to Ruby on Rails, looking for any suggestions to validate a phone number to be xxx-xxx-xxxx. Appreciate any suggestions. My phone_number column type is a string. Thanks!


Why ISO/IEC 9796 (signature with message recovery) instead of just encrypt the short message with private key?

I've had a look at  and read the very good answer  and I understand that signature and encryption are usually different algorithms. For clarity, here I am just talking of RSA.  For long messages usually a hash is computed, padded, and then encrypted with the private key, and sent along with the message. The receiver can decrypt the signature with the public key and compare with the hash (re)computed on the message (and verify the padding integrity).  For short messages ( m < N ), what I (still) do not understand is the need of complex algorithms like ISO/IEC 9796.  Given that encryption is not the important factor but only verification is needed, the sender could encrypt the whole message with the private key (like it is normally done for the hash). The receiver decrypts the message with the public key, gets the message and implicitly verifies the sender.  Obviously textbook RSA would be subject to existential forgery (which wouldn't be a problem with formatted messages) and maybe to multiplicative forgeries. So one has to add padding, like in standard RSA.  If there are security issues on this mechanism, for what I understand they are exactly the same than for standard signature. So the only downside is that without the public key the receiver cannot get the message.  EDIT: I'va also read the answers to  but as stated, I am asking in case of m < N.  So, are there more reasons not to encrypt the original message + some padding?


Why Zsh `time` not work for some commands?

Why Zsh time not work for some commands,  ➜  ~ type time time is a reserved word ➜  ~ time sleep 1 sleep 1  0.00s user 0.00s system 0% cpu 1.004 total # not work for echo ➜  ~ time echo hello hello # not work with for  ➜  ~ time for i in {1..3}; do curl -s http://baidu.com > /dev/null; done   but if change to bash these commands are both supported,   ➜  ~ exec bash bash-3.2$ type time time is a shell keyword $ time echo hello hello  real    0m0.000s user    0m0.000s sys 0m0.000s  bash-3.2$ time for i in {1..3}; do curl -s http://baidu.com > /dev/null; done  real    0m0.099s user    0m0.019s sys 0m0.018s


Algorithms for rainfall + river creation in procedurally generated terrain

I've recently become fascinated by the things that can be done with procedurally terrain and have started experimenting with world building a bit. I'd like to be able to make worlds something like Dwarf fortress with biomes created from meshing together various maps.  So first step has been done. Using the diamond-square algorithm I've created some nice hieghtmaps. Next step is I would like to add some water features and have them somewhat realistically generated with rainfall. I've read about a few different approaches such as starting at the high points of the map, and "stepping" down to the lowest neighboring point, pooling/eroding as it works its way down to sea level.  Are there any documented algorithms with this or are they more off the cuff?  Would love any advice/thoughts.


Why "People" use "are" but "Everything" use "is"?

Why "People" use "are" but "Everything" use "is" ?


Regex to get href value of particular  node

I have the following html content    <title>Simple</title>

Text.txt

    Here i have two  tags. I need the value of href of the  node where the attribute 'src' is that of the second  node i.e \"\"  I have a variable say string x which contains this value and i need to get the the href of the  node based on this value.  Right now i am using "href\s*=\s*(?:\"(?<1>[^\"]*)\"|(?<1>\S+))" but it gives me the href value of all the  nodes.


What do I do now if I contributed to Roth IRA in 2012-2013 and my MAGI exceeded the limit?

In 2013 I opened a Roth IRA for year 2012, contributing $4000 for year 2012.   In 2014 I contributed $5500 to that same Roth IRA for year 2013.  In 2015, I realized I was not eligible to contribute to a Roth IRA in 2012 and 2013 due to MAGI exceeding the limit. I opened a new account (Traditional IRA), deposited $5500, then immediately did a conversion to a new Roth IRA. (This is the "backdoor" approach as I understand it, is perfectly legal, and what I should have done in previous years). So I believe my Roth IRA account #2 (for tax year 2015) is in good standing  So now, what exactly should I do with the first Roth IRA account that I contributed to (incorrectly) for years 2012-2013? Luckily (?) there is only about $500 of gain in the account at this time.  If I re-characterize it as "Traditional IRA", have I missed the opportunity to do the conversion to Roth IRA for years 2012 and 2013?  Out of curiosity: Had I not caught this error, what would be the implications at Retirement time when I tried to take money out of the Roth IRA? Would the funds be treated as ordinary income (plus penalty?)   Lastly, with all this seemingly "fancy footwork" opening Traditional IRA and converting to Roth IRA, what documents (if any?) do I need to hold on to when it comes time to withdraw from the Roth IRA at retirement time to ensure the tax-free benefit?


Python * on arguments (not args or kwargs)

I saw in many python functions people using a single standalone "*" parameter, but it is not args or kwargs. I just saw an example on shutil standard lib documentation.:  shutil.copy(src, dst, *, follow_symlinks=True)   I tried to google it, but only found examples about args. What does this parameter do exactly?  Thanks.


Are there any styleguides, recommendations, best practices how to order items within a context menu? They question is about classic context menus, but I'm also interested in stuff about radial or more experimental approaches.  Basically what I've found in the Windows (and apple) guidelines:  Use a separator between groups of commands in a context menu to:       Distinguish groups of related commands. Group together sets of commands. Divide a predictable set of commands, such as clipboard commands (Cut / Copy / Paste), from app-specific or view-specific commands.


Missing vertical line at the end of the first line

I am new to Latex and I have tried to create a table but it seems not to work correctly - the vertical line is missed. Here is the code:  \begin{table*}[t]   \centering   \begin{center}    \begin{tabular}{|r|l|c|c|c|}     \hline &&\multicolumn{3}{c}{\bf Results}\\     \hline\bf Nr.& \bf Features&\bf Strict &\bf Outer &\bf Inner\\ \hline     1&Morphological F.&100.00&100.00&100.00\\     2&1 + Bla &100.00&100.00&100.00\\     3&2 + Blabla&100.00&100.00&100.00\\     4&3 + blablabla&100.00&100.00&100.00\\     5&4 + blablablabla&100.00&100.00&100.00\\     \hline    \end{tabular}   \end{center}   \caption{\label{font-table} Results. }   \label{tab:1} \end{table*}   Here is the output that I become :(    I think that something is wrong with the 5 line, but it seems I have tried everything :(


How do you change your Minecraft player name?

I really want to change mine but I don't know how to.


Consider:  Two units are headed your way. Two units are heading your way. Don't get me started! Don't get me starting!  Is there any difference in meaning? And I don't see why passive voice is used here. I would think they have similar meaning here. Help me to clarify!


Can I use two 7805 ICs in parallel to get double current capacity?

I use a 7805 for a project where the circuit needs a higher current (~2.8 A) at 5 V. So I assume that if I use both ICs in parallel I can increase the maximum current capacity. Would it work?


In vim search and replace, newline is rendering as "^@"

I copy pasted cells of a long google spreadsheet into a txt file that is a list of email addresses separated by commas. There are many "blank" cells as well, i.e. a blank space surrounded by commas. So I could have the following list:  bob@aol.com, ,john@aol.com, , , , email@email.com  In vim, when I try to add separate each address by a new line with this command:  :%s/, /,\n/g   instead of adding a new line after the comman, I get "^@" instead.   I know this has something to do with character sets, but I don't know how to fix it.


I want to start learning Linear Algebra, I have no background about this subject except high school mathematics that doesn't includes complex number and matrices. I found the following books: Introduction to Linear Algebra by Gilbert Strang and Linear Algebra Done Right and I can't decide which one to choose (if you know a better book, I would like to know).  I also would like to know if there is a practice book or a website with exercises that includes solutions.


Ubuntu 16.04 doesn't use my dedicated AMD graphics card

I have an AMD R5 M330 graphics card, but my system won't use it. I've tried checking if there are any proprietary drivers available, but nothing showed up. I want to know if there's a way i could configure my system to use that graphics card instead of my integrated Intel graphics card.  lspci -v | grep ATI 01:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Sun XT [Radeon HD 8670A/8670M/8690M / R5 M330] (rev ff) (prog-if ff)


Upgrade High-Trust Addin/App from 2013 to 2016

I have a SharePoint 2013 environment with several High-Trust Addins. This must now be upgraded to SharePoint 2016.  My Questions:   I was unable to find any documentation on the required steps. Links are welcome. Do i have to migrate App-Management Service and Subscription Settings Service?  don't even mention them.   say yes, but linked background is no longer available.  , i had to create a New-SPTrustedSecurityTokenIssuer. In this step, a RegisteredIssuerName had to be specified. This IssuerName consists of the Realm and the .   I think IssuerID can and should be migrated to SharePoint 2016, as it it also defined inside the High-Trust app. What about the Realm? This is by default the same value as FarmID. If i migrate this value, i have to change the Realm in SharePoint 2016. Or should i create the TST with a new Realm and existing IssuerID?


It is possible to use Pokemon images in a game?

Is it possible to use Pokemon images, names, elements in a game I would like to make? Are they still copyrighted, patented, would I get sued?  (Maybe their rights have expired by now, is what I am thinking?)


I am having an html email template which uses certain merge fields from a custom object. Now I am using following apex code to send certain emails to users.  Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();          mail.setTargetObjectId(t.OwnerId);          mail.setTemplateId(et.Id);         mail.setWhatId(t.Id);          mail.SaveAsActivity = false;         Messaging.sendEmail(new Messaging.singleemailMessage[] {mail});   Code is saved without error but when I run it it says "can't use whatId when sending email to users". Can anyone explain me how to overcome this error? When I use a visualforce template then same code works fine.


How can I mute the YouTube app while playing music on another player?

I do love to listen to music while watching text YouTube videos, but I can't because YouTube can't be muted.  I use the respect audio focus in  Music Player.  I have tried App Volume Control but it did nothing!


Using The Terminal Command to Shutdown, Restart and Sleep My Mac?

I'm getting more interested in using Terminal as an alternative way to address solutions on my Mac. I have seen this question entitled .  I would therefore like to know:  How to shut down, restart and sleep my Mac using the Terminal command exclusively ?


When does multiple inheritance come in handy?

Can you provide some real-world examples when problem can be more easily addressed using multiple inheritance rather than using composition or other alternatives?  When should one use multiple inheritance?  Why do some languages support multiple inheritance (C++, Python) and others don't (Java, Ruby)? I mean - based on what factors do creators of programming languages decide to include support for MI or not.


Minecraft player selectors based on NBT data

So 1.8 brought the ability to test for whatever the player currently has selected.  For example (maybe not exactly, but something like this),  testfor @a {SelectedItem:{id:minecraft:stick}}   How do you go about selecting based on this? I'm looking for something like this:  tp @a[SelectedItem:{id=minecraft:stick}}] ~ ~5 ~   I've tried many different permutations of syntax but the Command Block still outputs errors. Any ideas?


Updating a Normal Prior with Realized Data

So I am trying to remember how Bayesian updating works and reading the .  I'm reading a lot about how either variance or the mean must be known.  In what cases of real life data does this happen?  For example, lets say I have a basketball team like the Toronto Raptors and I believe that their points scored in the upcoming NBA season will come from some undetermined Normal Distribution.  In the meantime, I want to start with the realized mean and variance from last years results and iteratively update my new distribution as the results come in.  How would I go about doing this?  Please let me know if there is something obvious I am missing or a better way to go about this.   EDIT  I have read the post that I am being marked a duplicate of:       I am trying to understand how to derive the posterior distribution of a parameter $\mu$ given data vector $z$, $P(\mu|z)$, where $$\mu \sim N(0,A)$$ and $$ z|\mu \sim N(\mu,1).$$    I don't understand how it applies to what I asked.   I am struggling to understand the 2nd assumption and how it relates to what I am asking.  Maybe this is obvious to the people who marked it as a duplicate, but I am asking on a more basic level / asking for where I can go to learn about what I originally asked.


Can an $(a,b)$-knight reach every point on a chessboard?

An $(a,b)$-knight moves $a$ units horizontally and $b$ units vertically (or $b$ horizontally and $a$ vertically) for each move. For example, the traditional knight is a $(1,2)$- or $(2,1)$-knight. Does there exist general algorithms to the following problems?   Given $a,b$ and an infinite chessboard, can an $(a,b)$-knight reach every point on the chessboard no matter where it starts?  Given $a,b$ and an $m\times n$ chessboard, can an $(a,b)$-knight reach every point on the chessboard no matter where it starts? Here you can make the assumption that $m,n\gg a,b$ so the space won't be too limited for the knight to move.   In an infinite chessboard, it should be simpler, because the knight can reach every point if and only if it can achieve a single-unit up, down, left and right movement. For $m\times n$ chessboards though, I guess there might still be problems (or requirement for special treatment) with the edge or corner points, even when $m,n\gg a,b$?


Why can't current quantum computers break RSA?

We have quantum computers and we also have Shor's algorithm. So:    Why isn't RSA cracked yet?  What are the current quantum computers lacking?


How to move windows around and between monitors, using keyboard short cuts?

On MS Windows we can use Super + Arrow to move a window to the right and the left of the screen, maximize, minimize and even move it to another screen. Is there a way to configure this feature on Gnome?


"User was removed" means I lose my hard-earned points?

I have been using Stack Overflow for 2 years and 9 months. I really like the way this site works. But I am totally amused by how someone else's wrong deeds cost me my hard-earned reputation points.  I many times check my reputation loss and find the message "-10 user was removed". Come on,  why am I losing points for someone's wrongdoings? I just answered to help someone. I don't know personally whether he/she has the right intentions.   I have lost roughly 40-45 reputation points because of this. I have referred to all posts regarding this on Meta but didn't understand why this was required.  Is it time for policy change on Stack Exchange?


Do a question's (answer's) score affect its rankings in seach engines' results?

Typically, top SO-related results in Google search are highly upvoted questions (answers). It rarely happens to me to land on a question with negative score. I wonder if scores somehow affect the questions' rankings or it's only content that matters.


Is it okay to "ignore" small numbers in limits where $x$ approaches infinity?

I got a limit:  $$\lim_{x\to\infty}\frac {(2x+3)^3(3x-2)^2} {(x^5 + 5)}$$  As far as $x$ approaches infinity, can I just forget about 'small' numbers (like $3$, $-2$ and $5$ in this example)? I mean is it legal to make a transition to:  $$\lim_{x\to\infty}\frac {(2x)^3(3x)^2} {x^5}$$  Or if it is not always okay — in what cases such transitions are okay?


Solve the following PDE $$xu_x+(x+y)u_y=1$$ when $$u(1,y)=y$$ using method of characteristics and find the projections of the characteristics on the xy plane  $$\begin{cases} a=x\\ b=x+y\\ c=1 \end{cases}\Rightarrow \begin{cases} \frac{dx}{dt}=x\iff \frac{dx}{x}=dt\iff ln(x)=t+c_1\iff x=ke^t\\ \frac{dy}{dt}=x+y\iff \frac{dy}{dt}=ke^t+y\iff y=(kt+m)e^t\\ \frac{du}{dt}=1\iff du=dt\iff u=t+c_2 \end{cases}$$ How do I solve $?_1$ and what should be my next step?


I purchased a ticket with foreign passport but now I have a citizen Passport, What to do?

I need your advice.  I purchased a ticket with my Brazilian passport in January, and since then I received my Australian Passport that has a different 'first name', 'last name'. I called Qantas to change the name, and they said I would have to cancel my flight, get the refund, and purchase a new ticket with the current available price. They said that the Qantas ticket flight is not transferable, even though I'm not transferring the ticket, I'm changing my name to match the Australia Passport. Any advice? What can and should I do?


Suppose we consider a sequence whose all subsequences converges to the same limit then can it be claimed that the original sequence also converges to the same limit? And a mathematical proof will be helpful for the argument.


Why is the work top clipping out when i got to camera view?

[full renderThe camera's location and rotation shouldn't cause it and it only happens in camera. I am the noobiest of noobs so please be polite and patient with me. I'm sure you will all say just scale it down but i really don't want to. Image of problem, worktop clipping out in corner behind monitor.Trying to add more pics from other angles but can't seem to so sorry for that. Probably to old for this.


Has anyone, ever, successfully invoked the Metadata API from within Apex?

While researching a semi-related  posted here earlier, I dug up some interesting and conflicting information regarding whether it's even possible to use the Metadata API from within Apex. I used to be of the belief that this was strictly forbidden, as  seem to agree with. In a related  a Force.com MVP states:     "You can't callout to any Salesforce web services from within   Salesforce.  You can only callout to external web services."   But looking around I found some  posts along with a more recent post at the Force.com Cookbook which suggests that it  I've discovered plenty of people who claim that it is possible, though so far I can find absolutely nothing confirming that anyone has actually done this successfully.  For example, from this :     Yes. You can use Ajax Toolkit to call Metadata API calls, but this   possible only in VisualForce pages not Apex Class.      So if you (or anyone you know) has done this and can share the details of the process, or at least the steps to achieve a login and then a simple create() from within Apex, please share your results!


Insert an App part cross site collections

I have a web application with two site collections;   Team site Enterprise wiki    Now I want to display the latest 10 enterprise wiki pages inside the team site.  Now I try the following I went to the enterprise wiki, edit page, insert App part, select “Pages”. Then I edit the current view to display the latest 10 pages. But seems that I cannot do the same thing steps cross site collection, because when I went to the team site collection, I can not add a App part of type enterprise wiki ?  So can anyone advice, how to add a cross-site collection app part ? i read about creating external list, but i can not understand how i can locate the related enterprise wiki tables..  Thanks


Here are two examples from Murphy grammar textbook:  1)"I didn't see you at Michael's party last week - No, I had to work that night, so I couldn't come."  2)"I think I saw you at Michael's party last week- No, you couldn't have seen me. I didn't go to the party."  My question is:  Why in the first example is there no "couldn't have come" instead of "couldn't come" despite the past context ("...last week", "I HAD to work...")?


Sanitizing global string attributes - necessary or not?

Here is a DOM-based XSS flaw reported by SalesForce Security Review team in our code:   RootComponent  <aura:component extensible="true" abstract="true" access="global"                 description="Root template component">          <aura:attribute name="label"                     type="String"                     access="global"                     description="Label of the form input element" />       </aura:component>   SubComponent  <aura:component access="global" extends="c:RootComponent"                  description="Child extension of RootComponent">          {!v.label}       </aura:component>   According to SFDC, "any app can extend SubComponent component and pass in  as a label and trigger a DOM-based XSS attack." The solution would be to "sanitize" label global attribute to avoid such attack. What is meant by sanitization of global attribute?  I tried to reproduce the so-called security flaw , but as label attribute is of type "String" , when we send it HTML, it is displayed as a string, not as interpreted HTML ... so I don't see where the security flaw could be :/  <aura:application >     <aura:handler name="init" value="{!this}" action="{!c.doInit}" />      <c:SubComponent aura:id="TestXSS" label="DOM-based XSS attacks" />  </aura:application >   JS Controller  ({     doInit: function(component, event, helper) {         var XssAttack = '';        component.find('TestXSS').set('v.label',XssAttack);     } })   Output    We have global attributes everywhere. Our components are packaged and meant to be extended by client implementation. Do we actually need to sanitize them?


The dual of subspace of a normed space is a quotient of dual: $X' / U^\perp \cong U'$

I wanted to show that $X' / U^\perp \cong U'$, for $U$ being a closed subspace of the Banach space $X$.  Therefore I looked at $l: X' / U^\perp \cong U' , x' + U^\perp=[x']  \mapsto x'|_U$.  It is clear that this map is onto, as we just take a $u' \in U'$. Then I can use Hahn-Banach to get an appropriate $x'$ such that $x'|_U = u'$ and in particular $||x'||=||u'||$.  Now I need to show that is isometric: since we always have $\|[x']\|\le \|x'\|$ and by Hahn-Banach we have $\|x'\|=\|x'_{|U}\|$, this shows $\|[x′]\|\le \|x'_{|D}\|$ and it should be always true that $\forall y' \in U^\perp: \|x'-y'\| \ge \|x'_{|D}\|$, hence $\|[x']\|\ge \|x'_{|D}\|$. Is this reasoning correct? The isometric property follows.


sharing authentication within two drupal distributions

I am looking for a module or a way where two different drupal distributions can share the same authentication or user database ? Is there a module that can help with that ?  possibilities-  if user A logged into site-1,  the user should be logged in automatically to site-2.  if thats not possible, if user 1 creates a login on site-1, he should also be able to use the same login credentials on site-2 or vice versa.


Is there a built-in function or library that converts UTC time to milliseconds in Python?

The UTC time is formatted like this     "Tue 24 Dec 2013  5:53 AM UTC"   Is there a built-in function to convert it to milliseconds or I have to write my own scripts for it?


I have a $.each cycle and I need to access an external variable and I have troubles managing it. ex:  var f = obj instanceof QuadTable ? _.find(obj.tableCols, {data: arr[2]}) : $("#" + frm + ' input[name=' + arr[0] + ']');  $.each(arrTags, function (i, item) {         var arr=$(item).data('filter').split(":")         var y = obj instanceof QuadTable ? _.find(obj.tableCols, {data: $.trim(arr[0])}) : $("#" + frm + ' input[name=' + $.trim(arr[0]) + ']');         if (y.complexList || (y instanceof $ && y.hasClass("complexList"))) {                 var keys = obj.returnListKeys(y);                 var values = [];                 debugger;                 _.map(keys, function (name, i) {                     debugger;                     var k = _.findIndex(obj.dbColumns, {'db': name});                     values = arr[1].split('@');                     obj.dbColumns[k]["prv_value"] = values[i];                     obj.dbColumns[k]["nxt_value"] = values[i];                 });         }     });   My problem is how to access f inside $.each.


Can I use "To the memory of" for a place in the dedication part of a book? for instance, can I write "to the memory of my childhood gardens, that do not exist anymore"? or is there another expression to use?  Note that my question is different from the question "What's the proper way to dedicate a paper with a “to the memory of”?", which is already answered in this forum. In fact, my question is about the usage of "to the memory of" for a place whereas in that question "to the memory of" is used for a person.


Is there a way to customize the date range in Google Analytics and save that as my preference?

Whenever I open my Google Analytics account, it shows me a default date range (last one month). But I am not interested in this range and I always change it to display the last 3 days.   Just to highlight what date range I am referring to, here's a screenshot:    Is there a way to do this only once and save this to my preferences?


How to get list of all sobject records modified today in the system?

I need a list of all sobject records that got modified today. this is not just for one object but for all objects in the system. Is there a simpler way to do this?  Please reply.


I have the following problem: $$\sum^{\infty}_{n=1}\dfrac{2}{\left(n+2\right)\sqrt{n}+n\sqrt{n+2}}$$ I should find the sum of this sequence. I tried to simplify but it does not work.


Show that if $p=2^a -1 $ is prime then a is prime

Show that if $p=2^a -1$ is prime then $a$ is prime.    I found this problem very hard to solve and I only managed to show that $a$ must be odd; if $a$ was even we could rewrite $p$ as $$p=2^{2k}-1=(2^k-1)(2^k+1)$$ with $k$ different than $2$. Other than this I couldn't do anything else.


I want to know how to "Hide" a part of my code after it has been used and is no longer needed

I have been making a 5 question "Quiz" on Python. It is pretty simple in code design since I do not have much experience. I want to hide the previous questions so that the code is easier on the eyes and user friendly. I work on IDLE by the way. i="Incorrect, You lost points for this question." i2="Incorrect, Try Again." g="Good Job!" x=100 #percentage q1=input("What is 2+3? ") while q1 != "5":     x-=20     print (i,"Your current score:",x,"%")     q1=input("What is 2+3? ")     while q1 != "5" and (x<100):         print (i2)         q1=input("What is 2+3? ") else:     print(g)     print("Your current score:",x,"%")  Q2=input("What are the first 3 digits of Pi? ")...  This goes on 4 more times. I want all text that I displayed for q1 to disappear when the input value for Q2 appears.


Negative number comparison with is operator

Can someone explain to me why in Python 15 is 15 but -15 is not -15? Does that make any sense?  In [1]: -15 is -15 Out[1]: False  In [2]: 15 is 15 Out[2]: True   It looks like -15 is an instance of something.


Steps to reproduce:   Filter on tags Type a tag Select a tag Choose a question Tap back in menu bar   This takes me back to the tag filtering page instead of the filtered question page.   App Version: 1.0.89 Device Manufacturer: HUAWEI Device Model: HUAWEI P7-L10   OS Version: 5.1.1 (C900B852)


What is the effect of the birthday bound on the security of AES-GCM, when a very large number of messages are encrypted?  I am looking for attacks that are useful in obtaining information about the plaintext and/or creating forgeries, not just distinguishers.


asp.net webform allow access for only certain ip

We have an existing asp.net webform (.net 4) application runnning in production.  Recently the users have requested a new page be built, but that page they want only accessible through 1 ip address.  Can someone guide me on how to do this?  I've seen online ip restrictions at the IIS level, but I don't want to restrict the entire application as it should remain open to all, just that one page should be restricted.  Getting the users' ip I saw I can use the sample from    But is the only way then to restrict it to do a test if returnedIP == "xx.xxx.x.x" or is there a better way to handle this?


Does Rolle's theorem apply for roots at infinity?

Consider the function $$f(x) = \frac 1 {x^2+1}$$ $f(x) \to 0$ as $x \to \pm\infty$, thus we can say that $f(x)$ has roots at $\pm\infty$. Can we apply Rolle's theorem to prove $f'(c)=0, c \in (-\infty, \infty)$?   NOTE: $c=0$ does exist as specified above. This also works for other functions like $\frac{x}{x^2+1}$. However, is using Rolle's theorem a valid proof in this case?


Does store-bought salsa have an expiration date/shelf life after being opened?

So I like salsa, but don’t eat enough of it to use it all in a few days. In general, does store bought salsa—that is stored in the supermarket on open shelves without temperature control—go bad even if refrigerated after opening?  I’ve personally used store bought salsa a few weeks after opening and it smelled fine and there was no sign of mold. Was this an error on my part because I’ve never gotten sick from that stuff; just want a more informed answer if possible.


When I export my project to fbx some materials disappear and Its white But some materials are normal rendering. For example glass disapear but some easy materials are normal rendering.


What Stack Exchange site(s) is (are) appropriate for recommendations of website-building platforms allowing server-side access?

I've come to the point where I need my Squarespace  to do more than the Squarespace platform is designed to do, namely provide server-side access to  and . Squarespace permits no server-side access whatsoever even from within its "Developer Platform." The critical  on the site retrieves data stored on the AWS  servers and dynamically populates a table on the page. I need secure, credentialed access to the servers, thus requiring server-side Node.js and Ajax functionality. I need a site-builder because I'm not competent to build one and my non-profit group hasn't the money to hire a professional. Those twin requirements constrain the set of appropriate site hosts. It seems that I need to migrate the site to some other website-building platform similar to Squarespace but that allows server-side access. I would like recommendations for quality website-building platforms similar to Squarespace but that provide server-side access to Node.js and Ajax functionality. I would like to solicit recommendations from knowledgeable people for three to five sights ranked from most to least preferred with reasons. I would also like to know if you believe that more information about my site and its requirements is needed for a reader to respond effectively. What Stack Exchange site(s) is (are) appropriate for this specific question? Do you believe that more information will be needed? What?


I try to display windows explorer view as a static web page. We have to read a root folder and display all the folders and files as a static webpage. We have to use only client side programming. I know it is possible with the help of server side programming. My question is, is it possible to achieve it in front end without involving backend. I have only one problem which is reading the folder structure. How can I do it? I need to load a html file(ex..C:\workspace\treeview\index.html) in the browser and it should display all the files and folder. Also share your suggestions to achieve the above scenario?


There are lots references to completely changing a specific folder's icon with a custom one (Properties | Customize | Change icon).  What I want is, for a specific folder, embed a custom icon onto the default folder icon so that the end-user still knows that it is a folder.  The desired effect is similar to the system folders, like Documents, Pictures etc. shown here:    Here is a mock-up of what I am after:    This is for Windows 10 but I am hoping that it is possible to do this in Windows 7+.  Update: I am not looking for a programmatic solution or one that affects all folders that meet a certain requirement.  Rather, similar to how it is possible to completely change one specific folder's icon, I want to do that for a specific icon but keep the folder icon too.


Probability of having tails, if one of the coins flipped is heads.

I throw 2 coins at once, and my friend tells me that one of them landed heads. Find the probability of the other one being tails. I have 2 approaches in mind: The first one is to consider that there are 4 different events {HH,TT,HT,TH}, then the options of one being heads are {HT,TH,HH}. And those that have a tail are {TH,HT}. Then the probability of the other coin being tails is $\frac{card\{TH,HT\}}{card\{HT,TH,HH\}}=\frac{2}{3}$ However I also find intuitive that both are independent so the probability of having tails should be $\frac{1}{2}$


I learned that the historical present may be used to create an effect of immediacy in narratives. I have a question about the historic present tense. Why don't we use the progressive tense instead of the simple present tense?   ※My English skill is poor, so my question might sound rude. But I don't mean to offend anyone. I'd be glad if someone could reply to my question.


Python script has no effect when running as background

I'm trying to render some still images of a scene but switch the image texture using a script with the Blender command line. I made a script to set the image of an image texture node in the scene. When I run it within Blender with Run Script or run it with --python-text when launching Blender from the terminal the image is set correctly, but it has no effect when I run it along as GUI-less background with -b.   I'm still finding my way around the API so this is the extent of the script:  import bpy import os  def set_texture_image(img):     bpy.data.objects["Cube"].select = true     mat_tree = bpy.data.objects["Cube"].material_slots[0].material.node_tree     mat_tree.nodes["Image Texture.001"].image = img   new_image = bpy.data.images.load('//../../Pictures/cubes.png') set_texture_image(new_image)


Date filter in child record while creating roll up summary field

Is there any way that we can put the date filter on child record (like created in last one year) while creating roll-up summary field? I want to count only those child records which are created within last one year. I tried it by creating formula field on child object  but it does not appear while filtering the records (As per the doc: Automatically derived fields such as current date or current user are not allowed in roll-up summary fields). Any workaround if someone face this issue before ?


Problem installing phpMyAdmin on Ubuntu 19.10 (Eoan Ermine)

I just recently upgraded from Ubuntu 19.04 (Disco Dingo) to Ubuntu 19.10 (Eoan Ermine). My phpMyAdmin was removed while upgrading. Now I can't install it again.  I tried using:  sudo apt-get install phpmyadmin php-gettext   but it shows something like this:  Package phpmyadmin is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'phpmyadmin' has no installation candidate   So I searched from phpMyAdmin, apt search phpmyadmin, but I didn't find any.  How can I install phpMyAdmin on this version?


How come I never see cosmic rays in steam like they appear in a cloud chamber?

I just put like half a cup of water in a mason jar and put that in the microwave and accidentally left it in there for to long and it got boiling hot, then when I took it out and let it cool of course the glass cooled much quicker near the top away from the boiling liquid, and there was some very thick nice steam, one other variable is it's pretty cold in my house today. Anyways looking at the steam in the jar I was reminded of a cloud chamber I once saw which could detect cosmic rays, but looking at the steam closely for several minutes I didn't see any. Come to think of it I've NEVER seen cosmic rays in clouds that I've uhm... "created" so what is the difference between what I can make with  a jar and a microwave, and what scientists make for cr detection? And as a bonus question how could the microwave/ water jar set up possibly be improved?


maximum order of an element in symmetric group

While doing my homework i find out that the maximum order of an element in $S_3$ is 3 (the element $(123)$) and the maximum order of an element in $S_4$ is 4 (the element $(1234)$)  Can i generalize that and say that the maximum order of an element in $S_n$ is n?


User relationship module - error strict warning: Only variables should be passed by reference

module name: .  module version is: 7.x-1.0-alpha5  whenever i try to add relationship type or edit it give me this error:  Strict warning: Only variables should be passed by reference in theme_user_relationship_implications_form_table() (line 103 of C:\wamp\www\drupal\modules\user_relationships\user_relationship_implications\user_relationship_implications.module). Strict warning: Only variables should be passed by reference in theme_user_relationship_implications_form_table() (line 104 of C:\wamp\www\drupal\modules\user_relationships\user_relationship_implications\user_relationship_implications.module). Strict warning: Only variables should be passed by reference in theme_user_relationship_implications_form_table() (line 105 of C:\wamp\www\drupal\modules\user_relationships\user_relationship_implications\user_relationship_implications.module).   the code in user_relationship_implications.module is as follows:  function theme_user_relationship_implications_form_table($variables) { $form = $variables['form']; $headers = array(t('Relationship Type'), t('Strict'), t('Reverse')); $rows = array();  foreach ($form['opts'] as $rtid => $elements) { if (!is_numeric($rtid)) {   continue; } $rows[$rtid] = array(   drupal_render(array_shift($elements)),    drupal_render(array_shift($elements)),   drupal_render(array_shift($elements)), ); } return theme('table', array('header' => $headers, 'rows' => $rows)); }   in the above code line 103-105 is:  drupal_render(array_shift($elements)),  drupal_render(array_shift($elements)), drupal_render(array_shift($elements)),   Can you please help me solve the error and also bring to my knowledge why does this occur?


What is the distinction between $=$ and $:=$ when writing math?

I am persistently confused by the usage of $=$ and $:=$ when reading papers and writing in math. Quick google search on "When to use defined as (symbol)", returned no useful result.  The way I am currently using $:=$ is basically assign the name of a variable/quantity to another. For example, let $f(x):= \sin(x)$, then clearly $f'(x) = \cos(x)$. But if I write it this way, then wouldn't it also be acceptable to write:  $$f(x):= \sin(x) := \dfrac{\exp(ix) - \exp(-ix)}{2i}$$ After all, isn't $\sin$ defined as the difference of complex exponential over $2i$?  I have seldom seen anyone write this way (certainly not in any introductory calculus textbooks), therefore I am reluctant to follow this convention.  As another example, On Wikipedia, it writes:   But it doesn't follow this convention when defining functions, for instance:    I have also seen very varied usage of $:=$ when introducing sets. Some authors prefer to say something like: let $C:= \{x\in \mathbb{R}^2|x_1^2+x_2^2 = 1\}$, other prefer just to say $C= \{x\in \mathbb{R}^2|x_1^2+x_2^2 = 1\}$  Can anyone elaborate on under which context I should use $:=$ over $=$? What is a way to keep consistency?


what is the area of the region [ (x,y):0<x , y<1 , 3/4<x+y<3/2 ]?

can we do this without integration ( breaking the area into triangles & rectangles etc ) ?


I was recently asked why the following results holds   \begin{align} 1 \times 8 + 1 &= 9 \\ 12 \times 8 + 2 & = 98 \\ 123 \times 8 + 3 & = 987 \\ 1234 \times 8 + 4 & = 9876 \\ 12345 \times 8 + 5 & = 98765 \\ 123456 \times 8 + 6 & = 987654 \\ 1234567 \times 8 + 7 & = 9876543 \\ 12345678 \times 8 + 8 & = 98765432 \\ 123456789 \times 8 + 9 & = 987654321. \\ \end{align}  I honestly had some trouble giving my friend an answer.  After filling a writing block with pencil equations, I found a hint in a number theory book for a similar result and used the fact that any number can be represented as $N = a_n10^n+a_{n-1}10^{n-1}+\ldots a_110 + a_0$ and playing around with the above equations, one can see algebraically why this holds.    From my notes, I see that I showed that   $$(10-2)(1 \cdot 10^{n-1} + 2 \cdot 10^{n-2} + \ldots + n \cdot 10^0) + n = $$ $$(10-1)10^{n-1} + (10-2)10^{n-2} + \ldots (10-n)10^0.$$.     This is not very satisfactory.  I know from number theory, that there is a result $10 \equiv 1 \pmod9$ and I have seen some interesting consequences of it.  Can this result be used to show why the 'pyramid' holds?  Something similar perhaps?


Prove there is a polynomial $P_0$ with the property that $\mathcal{I}$ consists precisely of the multiples of $P_0$.

Let $\mathcal{I}$ be a proper ideal of $\mathbb{F}[x]$ where $\mathbb{F}$ is a field. Show that there is a polynomial $P_0(x)\in \mathbb{F}[x]$ with degree larger than $0$ with the property that $$\mathcal{I}=\{P_0(x)\cdot q(x):q(x)\in \mathbb{F}[x]\}.$$ (In other words, prove there is a polynomial $P_0$ with the property that $\mathcal{I}$ consists precisely of the multiples of $P_0$.)  Previously, I have proved     Let $\mathbb{F}$ denote the field described the set $$\mathbb{F}=\{r+si: r,s\in \mathbb{Q}\}$$   (Here $i$ is the infamous element of $\mathbb{C}$ with $i^2=-1$.) Consider   the function $\lambda: \mathbb{Q}[x] \to \mathbb{F}$ defined by   $$\lambda(p)=p(i) \qquad \text{ for all } p\in \mathbb{Q}[x]$$           1) Show that $\lambda$ is a ring     homomorphism.      2) Show that the kernel of $\lambda$ is the set of     all polynomials $p\in \mathbb{Q}[x]$ that are divisible by $x^2+1$.          Proof of (i): For $\lambda$ to be a ring homomorphism, we need to show that  > a) $\lambda(f+g)=\lambda(f)+\lambda(g)$      b) $\lambda(fg)=\lambda(f)\lambda(g)$      c) $\lambda(1)=1$         \textbf{\textit{Proof of a:}} Let $f,g \in \mathbb{Q}[x]$. Then we   need to show that $\lambda(f+g)=\lambda(f)+\lambda(g)$. So    $$\lambda(f+g)=(f+g)(i)=f(i)+g(i)=\lambda(f)+\lambda(g).$$      \textbf{\textit{Proof of b:}} Let $f,g \in \mathbb{Q}[x]$. Then we   need to show that $\lambda(fg)=\lambda(f)\lambda(g)$. So    $$\lambda(fg)=(fg)(i)=f(i)g(i)=\lambda(f)\lambda(g).$$      \textbf{\textit{Proof of c:}} Let $f=1 \in \mathbb{Q}[x]$. Then we   need to show that $\lambda(1)=1$. So $$\lambda(1)=1(i)=1.$$      Hence $\lambda$ is a ring homomorphism.      Proof of (ii):  We need to show   that the kernel of $\lambda$ is the set of all polynomials $p\in > \mathbb{Q}[x]$ that are divisible by $x^2+1$.      Suppose $x^2+1|p(x)$. Then $p(x)=(x^2+1)g(x)$ for some $g(x)\in > \mathbb{Q}[x]$. Using part (i), we can show that $p(x) \in > ker(\lambda)$ (i.e. that $p(x)=0$):   $$\lambda(p(x))=(x^2+1)g(x)=(i^2+1)g(i)=0\cdot g(i)=0$$ Hence we have   show that $p(x)\in ker(\lambda)$.      Suppose $p(x) \in ker(\lambda)$. Using the Euclidean division   over $\mathbb{Q}[x]$ to divide $p(x)$ by $x^2+1$. We obtain:       \begin{equation*} \begin{aligned} 0 & =\lambda(p(x)) \\ & > =\lambda(q(x)(x^2+1)+r(x))  \\ & =\lambda(q(x))\lambda(x^2+1)+\lambda(r(x)) \\ & =p(i)(i^2+1)+r(i)  \\ & =r(i) \\ \end{aligned} \end{equation*} Hence we have show that the   remainder is $0$, which implies that $p(x)=(x^2+1)g(x)$.       Hence, the kernel of $\lambda$ is the set of all polynomials   $p\in \mathbb{Q}[x]$ that are divisible by $x^2+1$.   I know both proofs are related to one another. So what is needed to change in the previous proof for the new proof?


I have always used the phrase "some water" and "a little water" interchangeably. Recently I took an English quiz and the question was :     Please give me (a little / some) _____ water to drink.   I marked 'some' as the correct answer but found out that 'a little' was correct. Searching similar sentences on Google also confirms this. Is the use of 'some' here incorrect?  PS: I found many sentences where 'some' is used in this construction :     Please, may I have some water in a cup   Is there any reason for using the specific phrase in that context?


How to unblock something listed in rfkill?

I think I may have found the cause of my problems with connecting to wifi in Ubuntu 11.10.  I type this in Terminal:  $ rfkill list all 0: phy0: Wireless LAN     Soft blocked: no     Hard blocked: yes 1: acer-wireless: Wireless LAN     Soft blocked: yes     Hard blocked: no $ rfkill unblock all $    If I am correct I must unblock all of those "yes", right? But nothing happens when I try to unblock. Am I typing the wrong command?    Typing sudo modprobe -r acer_wmi seem to have added another problem, now I can't even try to click on the "Enable wireless"-button as it has been grayed out and 1: acer-wireless: Wireless LAN does not show anymore in the rfkill list. Does anyone have any idea how to fix that?  EDIT: I rebooted and now it is not grayed out anymore and the rfkill list all shows as:  0: phy0: Wireless LAN     Soft blocked: no     Hard blocked: no 1: acer-wireless: Wireless LAN     Soft blocked: yes     Hard blocked: no   The 0 is not Hard blocked anymore, but I guess 1: acer-wireless needs to be put off soft blocked somehow.


Why does pressing the flag button make you fail an audit?

Few arguments against it:   Pressing the flag button doesn't mean actually submitting it (as in every test/form). There might be an unknown duplicate, if you assume it's the first post (as you were told) it might be worthy to flag it. You might want to look if someone else thought it was duplicate by "making half way" to flagging it.   Why pressing the flag button makes you fail an audit? I think it shouldn't.  Edit:  The implementation difficulty (fake flagging UI) and the tips about how avoid failing (and reviewing!) by skipping the answer adds some insight, but still doesn't answer the question why it's not a valid review.    Moreover, I would like to add one more,  describes a reviewer that failed an audit while trying to flag a question as off topic. The question was clearly off topic, and still after 1300 views no one flagged it.


Is there a tool to convert the pdf files to chm?

I am looking for any package or tool to convert pdf files to  chm. Is there such a tool?  I am running Ubuntu 13.04


I'm looking for a textbook or set of lecture notes on gauge theory for mathematicians that assumes only minimal background in physics. I'd prefer a text that uses more sophisticated mathematical concepts like principal bundles and connections, and categorical language whenever convenient.


I have a hardtail mountain bike and recently I broke the 4 year old chain that I had on it. I’m looking for a new one and I’m wondering how many links I need for a 3x9(27 speed) bike.


Warn new users when they ask a question after a previous question is closed, downvoted, or deleted

Another "miséricorde":  Consider  (emphasis added):  I think its okay, please dont take any efforts for me. I personally do not feel the system helps ask good questions. I dont know why asking for a software in this case is bad. Basically I needed a command that would give me this data. There is no other way I could have asked the question. I could have changed the question just for the sake of changing. I feel I am better off elsewhere. Thanks for your very very prompt responses. Regards. Bye. – user1744649  We just lost another user due to inadequate guidance on what questions are allowed.  The  by the time they are banned has been proven incorrect. Given that , we need a better way to make sure that users can understand how to ask good questions and what types of questions are allowed. I suggest that we warn newcomers, in a clear but positive tone, when one of their questions has been closed, downvoted (to a score of -2 or lower), or deleted, so that they don't repeat the same mistake.  This is probably best done the next time the user asks a question, and should appear as an "interstitial" page prior to reaching the actual Ask Question form.  The page should not appear to users:  with at least 50 (or perhaps 75 or 100) reputation that have asked a good question since the last downvoted/closed/deleted question that have fixed a bad question and had it reopened/undeleted/upvoted.  The content of the page should be adapted based on the specific problem with the previous question.  I would imagine something similar to the following (example for a question closed as off topic on Super User):  Before you ask another question... One or more of your previous questions have been closed as off topic. The scope of on-topic questions is defined in the , as follows:  What kind of questions can I ask here? Super User is for computer enthusiasts and power users. If you have a question about …  computer hardware, computer software, or personal and home computer networking  and it is not about …  programming and software development, video games or consoles, websites or web services like Facebook, Twitter, and WordPress, electronic devices, media players, cell phones or smart phones, except insofar as they interface with your computer, issues specific to corporate IT support and networks, asking for a shopping or product recommendation,  … then you’re in the right place to ask your question!  Please make sure that the question you are about to ask is on topic as described above. If you need help determining whether your question can be asked on this site, you can ask for advice on  or . You may also want to edit your previous question to address any problems associated with it. To ensure a high standard of content quality and prevent disruption to the community, users who repeatedly post low-quality questions  Continue  The  doesn't address this issue as it is shown only to users with 10 reputation or less (rather than up to 50 and possibly higher) and does not address the specific problem with previous low-quality questions.  The point of this feature request is to provide a easily understood targeted message that actually teaches the user about what happened with the previous question he or she asked.  The EULA is generic and may not have conveyed the intended message clearly if the user still asked a low-quality or off-topic question. For reference,  currently has 143 reputation and the proposed message would probably have been shown after the first closed or deleted question. I know this can be a complex feature to implement, since it needs to be adaptive, but this should help eliminate confusion on what the rules are and minimize the incidence of good-faith users getting post-banned.


Bit copied a disk image using the dd command to a new and bigger disk. How do expand whole LVM?

I just copied a 50 GB disk image using dd for bit copying to a new harddisk with 200 GB storage. On the disk is LVM including the system partition EXT4 and a swap partition (both LVs).  Well the copy is running and works great. Now I would like to expand the whole LVM VG, and LV and also the underlying EXT4 to use the whole disk.  At the moment it still claims to have 50 GB only. I would like to extend it not at a second disk to the Volume Group. What would be the best way to do it?


Can I use images showing up in Google search for my presentation slides without violating any copyright?

I am teaching a freshman science course for the first time and I am doing also outreach activities in high schools. To be able to attract the young generation to science one has to connect the concepts with everyday applications.  So I build my power point slides using pictures from the textbooks which we officially use. Unfortunately when one does a Google search on any subject by images, one gets much more appealing and fascinating pictures. Some of these pictures are even related to simple applications which are explained in popular science sites on very recent discoveries. The problem is that I cannot use those pictures from Google sites in my slides because they are copyrighted.  What should I do then? Should I stick to the boring-looking textbook pics to avoid copyright problems, or bring life to my course by using images Google shows up (but then I might go to the jail!)?  Is there something that says one can use images shown by Google for educational purposes with no copyright issues?


Determine the number of positive integers that share at least one of the numbers

The question:   Determine the number of positive integers that divide at least one of the numbers $3680$ and $100$.  The answer:   We have that $3680 = 2^5\cdot5\cdot23$ and $100 = 2^2\cdot5^2$  The number of positive integers dividing $3680$ is therefore $6\cdot2\cdot2$, the number of positive integers dividing $100$ is $3\cdot3$, and the number of positive numbers that divide both $3680$ and $100$ is $3\cdot2$. The number sought is thus $24 + 9 − 6 = 27$  What I need help with  I don't understand the resesing for dividing $3680$ is therefore $6\cdot2\cdot2$ and dividing $100$ is $3\cdot3$


After a US B2 visa refusal, do I qualify for ESTA/VWP under my new UK citizenship?

I had applied for a US B2 visitor visa in 2014 but I got refused. At that time, I applied with my Philippine passport.   Now, I am a UK citizen and have a British passport. Am I qualified for the ESTA/VWP or should I apply again for a B1 visitor visa?   I am traveling in April but I really don’t know what to do. I am worried I may not qualify for the ESTA.


"My and my sister, Anna Smith's records" or "My and my sister's, Anna Smith, records."

I'm writing a request letter to my and my sister's high school but I don't how to properly say it.  I, Rebecca Smith, would like to request a copy of my and my sister, Anna Smith's Transcript of Records.  or  I,Rebecca Smith, would like to request a copy of my and my sister's, Anna Smith, Transcript of Records.  if both are wrong, please tell me a better sentence and also, if something is wrong in this question, you can correct it. Thank you very much


How to correctly assess the correlation between ordinal and a continuous variable?

I'd like to estimate the correlation between:  An ordinal variable: subjects are asked to rate their preference for 6 types of fruit on a 1-5 scale (ranging from very disgusting to very tasty) On average subjects use only 3 points of the scale.  A continuous variable: the same subjects are asked to quickly identify these fruits, which results in an mean accuracy for the 6 fruits.   Is Spearman rho the best method to analyze these data and/or are there other good methods I could consider?


Does $\sqrt{a+b} \le \sqrt a + \sqrt b$ hold for all positive real numbers a and b?

I thought of this a while ago, but can't make up a proof or a counterexample. Does anyone know more about this?  $$\sqrt{a+b}  \le \sqrt a + \sqrt b , \forall a,b \in \mathbb R_+$$  Moreover, what happens with more variables? Say:  $$\sqrt{x_1+x_2+...+x_n} \le \sqrt x_1 +\sqrt x_2 + ... + \sqrt x_n $$  with $ x_i \in\mathbb R_+ \forall i \in \{1,2,...,n\} $  Or when $i = \mathbb N$  PS: I tried looking on the internet for this but I don't know how I would call this.


How to work out modular arithmetic quickly for cryptography

I am not so good at Mathematics so please kindly forgive my stupidity.  Basically, I am learning modular arithmetic for cryptography and so I am struggling in understanding how to do big modular arithmetic calculation without a calculator.  So for example, how would I do this question: 6^56 mod 19?  I get that you need to convert the power 56 into binary - so that would be 0111000. So like 2^32 + 2^16 + 2^8.  I then understand you have to do like:  6^8 mod 19 then 6^16 mod 19 and 6^32 mod 19.  I've been told I can use the chinese remainder theorem - but I want to know how to do this all.    Any help would be absolutely great! I like this stuff but I have been struggling a bit.


Are HSA manual vs. payroll deductions exactly the same benefit

If I have money taken from a paycheck, it comes out pre-tax. Not just state/federal, but pre-FICA too.  I am closing on a home and won't have a house payment until February. For this reason I am considering NOT contributing any HSA money through my paycheck and instead writing a check for the MAX HSA contribution in early January into my account. This contribution is simply out of a bank account hence it is post tax. So my question is: When I file taxes for this year will the amount I owe/get be offset by the same amount or is there an inherent benefit to having the payroll deduction?  The reason I want to do this is:   I have pre-spent medical for the entire year and can immediately withdraw this money back into my account, so there's no out of pocket expense here other than missing the money for a week or two. I will get a higher paycheck for the rest of the year since I am not contributing per check. This will be more helpful after starting a house payment. Although I'll pay slightly more in taxes per check (higher brackets all year), this would again work itself out at tax time.


How to pronunce th+s like in paths or months?

I always feel it's kind of hard to pronunce them both, can either of them be dropped or reduced?


schengen visa issued by French consulate in South Africa - free movement to Switzerland?

I am in France on a schengen tourism visa on my South African passport. My plans when I applied for the visa were to visit france, Germany and the Czech republic. Is there any reason why I would not be allowed to make an adjustment to my itinerary now that I am here and make a side trip to Switzerland on this visa? The reason for this is to break up a long train trip between Germany and France.  Family of mine say that they had problems because they required schengen and a separate visa for Switzerland. This seems contradictory to the schengen idea of free movement and everything else I've read. Just in case, can anyone confirm this for me?


Can I use an image located on the web in a LaTeX document?

I have tried  \includegraphics{http://www.site.com/path/to/figure.png}   But this returns the error   ERROR: Package pdftex.def Error: File `http://www.website.com/path/to/figure.png' not found.    Are there other options?


Using arrays or std::vectors in C++, what's the performance gap?

In our C++ course they suggest not to use C++ arrays on new projects anymore. As far as I know Stroustroup himself suggests not to use arrays. But are there significant performance differences?


How to install flash payer in Ubuntu 14.04 LTS?

How to install flash payer in Ubuntu 14.04 LTS ? Also how to get the root permission ?...


About partitions, majorization, and conjugates

I am trying to solve a question of a property of conjugation. What I am trying to show is that conjugation reverses the order of majorization.  Let $\lambda$ and $\mu$ are partitions of n and $\lambda$ is majorized by $\mu$.  $\lambda:n=\lambda_1+\lambda_2+\lambda_3+ \cdots + \lambda_k$  $\mu:n=\mu_1+\mu_2+\mu_3+ \cdots + \mu_k$  '$\lambda$ is majorized by $\mu$' means that $\lambda_1+\lambda_2+\lambda_3+ \cdots + \lambda_i \leq \mu_1+\mu_2+\mu_3+ \cdots + \mu_i$ for $i=1,2,\cdots,k$  Then, showing that $\mu^*\leq\lambda^*$ would be enough to say that conjugation reverses the order of majorization.  But, I am stuck from the beginning after writing the definitions of majorization and conjugation.  Please help me. Thanks


What's the difference between "to verb" and "that S+V"?

Are these sentences the same in meaning?        I want you to leave me alone.   I want that you leave me alone.       If not, what's the difference between the two?


Time travel short story where dinosaur doesn't taste like chicken

I ran across this  and it reminded me of an old short story I read a long time ago.  I read it in a collection of short stories.  It would have been a book because I borrowed it from a school library.   Probably in the 1970s or 1980s.  The book and the story would have been older, though.  Probably from the 1960s or earlier.  In the story, a scientist has a machine that he can use to view the past.  It isn't like a TV or something, though.  It opens a portal into the past that he can look through.  It is very difficult to control, though.  Pointing it at a place and time is likened to working in a hurricane.  The portal jumps and moves about randomly.  The steadier he can hold it, the clearer the past appears.  When it is really steady, he can hear sounds from the past.  It never gets really steady enough to reach through.  They try pushing tools through the portal to pick up things in the past.  The steadier the portal, the easier it is to push tools through.  It never gets steady enough for them to push a tool all the way through, though.  It just gets easier to make progress.  One day, they have the portal open and it is acting really wild.  At some point the workers take a break.  The portal is still open, and while they are loafing the portal settles down by itself and becomes steadier than it has ever been.  So steady that a piece of the past falls through.  The portal scooped a chunk of the ground out of the past.  The chunk of ground contains a nest with dinosaur eggs.  The scientist  rescues the eggs, and they manage to keep them warm enough until they hatch.  The dinosaurs are some kind of harmless things, and become the lab mascots.  Always wandering the grounds, and in and out of the lab.  One day, the have the portal open again and one of the dinosaurs wanders into the lab and walks into some high voltage terminal.  Crash, bang.  Short circuit.  All the equipment to open the portal is destroyed, and the dinosaur is roasted from the flash.  The roasted dinosaur smells good, like chicken, and the scientist's son (who has been telling the story) takes a bite to see what it tastes like.  He says "It resembled chicken the way an asteroid resembles Jupiter."   It tastes fantastic. With all of their work ruined, and the ruins of a fortune in expensive equipment scattered around them, the scientists and the labworkers all chow down on dinosaur.  Half raw, half burned to a crisp from the explosion.  They eat the dinosaur down to the bones.  They start breeding the dinosaurs, and sell them as food.  The guy's father makes a fortune selling dinosaur meat, but remains unhappy.  With money from selling dinosaur meat, he rebuilt his lab but never ever got the portal steady enough to actually visit the past or take samples.  Does anyone know the name of the story and the author, and maybe what collection it might have been in?


intersection of two files according to the first column

I have two files in  file A, there are sequence_numbers in the other file B, there are many columns, and the first column is sequnce numbers, I want to get a files with all the lines in the B with the sequence numbers which are in the A how can I achieve this? thanks  like file A  1 3 8 9 20   file B  1 kfjk 3243424 2 fkdkf 23543592 3 iefjk 21493402 7 dlafdl 23435231 8 kfkdlkf 309834


How can't install a 338KB app when I have 474MB free?

I have a Motorola phone, with 8GB of internal memory.  To my surprise, in a few days, I had 474MB of free space, but couldn't install a 338KB app!! So, clearly the limit of ~25MB referred to in some comments ( and ) are not always the case. A user just told me the following:     Actually it's "25MB or 10% of the storage", whichever is hit first. So   with e.g. 10 GB internal storage, it would hit you as soon as you drop   below 1 GB free. Crazy, but that's what it is.   Actually, that's not correct, because I didn't have to free up 1GB of internal memory. But anyway, half a gigabyte is enough to run a full operational system. I've seen similar complaints of hundreds of MB not enough to install apps ~ 1MB or similar small operations ( and ).  What's wrong here?


How long can I stay in Canada as a tourist with the new eTA? (italian citizenship)

The Canadian  states that starting March 2016 some tourists that fly into Canada will need an .  As an Italian citizen  and I think I may stay . Is this period subject to change with the introduction of eTA? Just for clarity, I will be entering Canada by flight.


How to deal with invalid, but still community-approved edits?

has been edited by .   , see revisions 3 to 4.   Now what he did is totally inexplicable to me, as a matter of fact he destroyed the answer. The new version is neither syntactically valid nor does it make any sense.  Still, the edit got "peer-reviewed" and nodded off.  Is there any way to deal with these kinds of things, other than sighing heavily and rolling back the edit?  Rhetorical side question: Could this be a side-effect of people grinding for reviewer badges?


2018 MBP Network Throughput decreases over time

Summary  I was recently provided with a 2018 MBP by my employer. The network throughput slows gradually until I'm forced to reboot.  Setup  The following machines are connected via wired ethernet to a gigabit switch:   2018 MBP (the problematic machine, 10.14.4) 2015 MBP (the control, thunderbolt ethernet adapter, 10.14.4) 2010 iMac (the test target, built in ethernet, ubuntu)   The 2018 MBP has a usbc-thunderbolt adapter, with a thunderbolt display attached and the ethernet cable connected to the display.  When the throughput drops, I've tried the following:   Switch to WiFi - doesn't help, speed starts off around 300MBit/s but drops to the level the wired connection is currently at. Use a different switch port / ethernet cable - doesn't help Test speed on control MBP using 2018 MBP's ethernet cable & switch port (it's fine) Connect thunderbolt monitor to control MBP and test throughput (also fine)  Disconnect usbc-thunderbolt adapter incase it's doing something odd (no difference) Disconnect power from 2018 MBP (no difference) Sleep/Wake 2018 MBP (no difference)   I setup a test to show the problem: rebooted the 2018 MBP then looped  making connections to the iMac and plotted the results, sure enough after a couple of days I'm getting 10MBits/s across a gigabit switch:    The problem isn't the iMac (test target) as I also made periodic tests from the control MBP to the iMac which consistently showed ~940Mbits/s.  I've been using the 2015 MBP and thunderbolt display with it's ethernet connection for years without issue, and have ruled that out as a cause. Also WiFi shows the same problem, which suggests its not related to a specific interface. I suspect a software problem with the networking stack on the 2018.  Potentially suspicious software:   Symantec Endpoint Protection (mandated by employer) Pulse Secure (required for VPN connection to employer, but not connected during these tests) Docker (required for development, does add bridges etc to local networking - this doesn't cause a problem on the 2015 MBP though.)   Questions   Any idea what this might be about? Is there any way to reset the networking stack or some workaround that doesn't involve a reboot?   Unfortunately removing SEP is not an option :(


I want to generate a string-code for the user that represents his progress in the game (so he can load this state somewhere else). I don't want him to be able to guess the system and thus load a state which he hasn't yet achieved.  The following variables are involved:   A number X between 1-30 representing the highest level he unlocked. For each level lower than X a boolean representing whether he made the level on hard or not. For each secret object he could have found (also roughly 30) another boolean.   My idea was to just build a binary number from all these but that's just way too easy for the user to hack. If he beats level 1 and then saves, he will see his code being something like 0x1, while having bet level 10 will be something like 0x200.


Windows 8: My account is listed as Administrator, yet often I will get errors telling me I need to be an administrator?

For example I was fixing an issue with my Iphone which required me to change the hosts file in sys32.. But the computer would tell me I am not allowed to and to contact an administrator. I've already tried Net user administrator /active:yes but even when trying to change and save the hosts file while logged in on the Administrator-account, it will tell me I cant do that.. How do I give myself full access? this is really frustrating


How to compare a parameter with an object in Java?

Would anyone know how to compare an parameter with an object? I've been trying to do it following the instructions given in the last question here:  But, doesn't seem to wrork.  public class Classification     {         String changes;         String rating;         String description;      Classification()     {         rating = "G";         description = "Suitable for general audiences";     }      Classification(String must)     {         if(must != "G" || must!= "PG" || must!="M")         {             throw new NullPointerException ("Not equal");         }         rating = must;         if(rating == "G")         {             description = "Suitable for general audiences";         }         if(rating == "PG")         {             description = "Parental guidance recommended";          }         if(rating == "M")         {             description = "Suitable for mature audiences";         }     }      Classification (int num, String para)     {         if(num!= 13 || num!= 15 || num!=16 || num!=18)         {             throw new IllegalArgumentException("Not equal");         }         if(para==null)         {             throw new NullPointerException("String is null");         }         if(num == 16)         {             rating = "R";             description = para;         }         changes = rating + num;     }      void printClassification()     {         print("Rated " + rating + ": " + description);     }      void derestrict()     {         if(rating == "M")         {             rating = "PG";             }         if(rating == "PG")         {             rating = "G";         }         if(rating == "G")         {             throw new IllegalArgumentException("G is least restrictive");         }         if(changes == "R18")         {             changes = "R16";         }         if(changes == "R15")         {             changes = "R13";         }     }      Classification isLessRestrictive(Classification compare)     {         if(compare==null)         {             throw new NullPointerException ("Classification para is null");         }         if(changes<compare)         {             return true;         }         return false;     } }


How do we refer to "whose absence" when it's an object instead of a person?

Explanation of what I'm trying to communicate:  Suppose that there is an object, Vinegar (say).  And we're marinating chicken before roasting it. If vinegar was added to the marinade then the roast turns out to be good. If it wasn't, then it's going to be smelly and "rubbery".  Now let's say that I didn't know this and some person X found out about the requirement of vinegar and informed me.  My sentence:  "Today, I added a new ingredient, Vinegar, in the marinade, whose absence causes chicken to be smelly, found by person X".  Is the above sentence correct? It feels somewhat off. I have 2 queries regarding this:  1) Is the phrase "whose absence" correct? If not then what other phrase can we use in its place?  2) Is there a better way to frame this whole sentence rather than breaking it into smaller sentences (for the sake of improving grammar)?


Is there Touch AC and/or Flatfooted AC in 5th Edition D&D?

Does D&D 5E have a mechanic similar to  or  as it exists in D&D 3.5?  To put it simply, in D&D 3.5, touch AC excludes armor bonuses when armor can't help against an attack, and flatfooted AC excludes your Dexterity bonus when you haven't acted yet in combat.


Conjugate prior to a Dirichlet sample distribution?

The Dirichlet distribution is the conjugate prior to the multinomial sampling distribution.  What is the conjugate prior (if any) if the sampling distribution is itself Dirichlet?  That is, our samples are nonnegative vectors $\mathbf{p} \in \mathbb{R}^k$ which sum to 1, and we are trying to estimate a distribution over the parameters $\mathbf{\alpha}$ to the Dirichlet distribution that produces $\mathbf{p}$.


Which is the Best Free Physics Simulator that can simulate the dropping of a ball?

We were asked in class to use a physics simulator beforehand to test the conditions of an experiment we are going to do and save it to use in our report. The experiment involves the dropping of a ball and measuring its efficiency afterwards Is there any configurable simulator that would allow us to change the height and spin on the ball being dropped, while taking into account air resistance, natural forces, etc? And is it able to give values of kinetic and gravitational energy as well as outputs of the set configuration at any point the ball may be at? Something like  would be good I know an experiment like this doesn't typically need a simulator and the math can be figured out by hand but our teacher has asked us to develop one and share it with him all the same


How to display background images in perspective?

I am trying to find out how to approach a relief type project. I have a background image and a flat plane mesh to sculpt on, but I actually don´t see any changes looking straight on top. When I tilt the perspective a bit the image disappears.  Is there a way to make the image appear at all perspectives?


The negative binomial distribution NB($m,r$) is defined as $$\Pr(X = k) = \left(\frac{r}{r+m}\right)^r \frac{\Gamma(r+k)}{k! \, \Gamma(r)} \left(\frac{m}{r+m}\right)^k \quad\text{for }k = 0, 1, 2, \dots.$$ I'm interested in finding the Jeffreys prior for $m$ and $r$. I could not find this anywhere, most of the results assume $m$ fixed. I tried to derive the expression but got stuck, not sure how to proceed or simplify the expression.  $$\frac{\partial^2 ln P}{\partial m^2} = \frac{k+r}{(m+r)^2} - \frac{k}{m^2}$$ and  $$\frac{\partial^2 ln P}{\partial r^2} = ...$$


Why use the word "copy" in "do you copy that"?

I notice "do you copy that?" is used in movies to ask for confirmation in telephone/interphone conversation.  I only know copy means make things duplicated, so why use it in "do you copy that"? Is there a history about it?


Installing QGIS plugin called profile from line?

i am trying to install a new plugin called profile from line and then this error appear and i dont konow what to do.  Couldn't load plugin 'profilefromline' from ['C:/Users/LOUREN~1/DOCUME~1/NEWFOL~1/Quantum GIS Lisboa/apps/qgis/./python', 'C:/Users/LourenÃ§o AmÃ©lia/.qgis//python', 'C:/Users/LourenÃ§o AmÃ©lia/.qgis//python/plugins', 'C:/Users/LOUREN~1/DOCUME~1/NEWFOL~1/Quantum GIS Lisboa/apps/qgis/./python/plugins', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\bin\python27.zip', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\DLLs', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\plat-win', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\lib-tk', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\qgis\bin', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages\PIL', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages\win32', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages\win32\lib', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages\Pythonwin', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages\wx-2.8-msw-unicode', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\qgis\python\plugins\fTools\tools']  Traceback (most recent call last):   File "C:/Users/LOUREN~1/DOCUME~1/NEWFOL~1/Quantum GIS Lisboa/apps/qgis/./python\qgis\utils.py", line 143, in loadPlugin     import(packageName)   File "C:/Users/LOUREN~1/DOCUME~1/NEWFOL~1/Quantum GIS Lisboa/apps/qgis/./python\qgis\utils.py", line 309, in _import     mod = _builtin_import(name, globals, locals, fromlist, level) ImportError: No module named profilefromline  Python version: 2.7.2 (default, Jun 12 2011, 15:08:59) [MSC v.1500 32 bit (Intel)]  QGIS version: 1.8.0-Lisboa Lisboa, 6416f38  Python path: ['C:/Users/LOUREN~1/DOCUME~1/NEWFOL~1/Quantum GIS Lisboa/apps/qgis/./python', 'C:/Users/Louren\xc3\xa7o Am\xc3\xa9lia/.qgis//python', 'C:/Users/Louren\xc3\xa7o Am\xc3\xa9lia/.qgis//python/plugins', 'C:/Users/LOUREN~1/DOCUME~1/NEWFOL~1/Quantum GIS Lisboa/apps/qgis/./python/plugins', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\bin\python27.zip', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\DLLs', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\plat-win', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\lib-tk', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\qgis\bin', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages\PIL', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages\win32', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages\win32\lib', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages\Pythonwin', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\Python27\lib\site-packages\wx-2.8-msw-unicode', 'C:\Users\LOUREN~1\DOCUME~1\NEWFOL~1\Quantum GIS Lisboa\apps\qgis\python\plugins\fTools\tools']


Relationship between RAM & processor speed

RAM is just used for temporary storage. But since this storage is in the cpu memory (RAM) it is fast. Programs can easily read/write values into it. I've noticed more the RAM less time it takes for the application to load/execute. But doesn't this actually depend of the processor speed (MHz or GHz values). I am wondering what is the science/relationship between processor speed and RAM.


echo text after curl command on same line

#!/bin/bash echo "$(curl -s -I https://google.com|grep Server)" abc   returns:  abcer: gws   and bash -x shows:    ++ grep Server ++ curl -s -I https://google.com ' abco 'Server: gws  abcer: gws   but    echo abc "$(curl -s -I https://google.com|grep Server)"`    returns  abc Server: gws   In other words, if I add text AFTER the curl command, it gets mangled, but it's ok if I add it before curl. What is happening? I cannot figure it out.


Which Defiant was shown in ST: First Contact?

In Memory Alpha, the page on the  states that two Defiant-class ships had that name: the prototype Defiant, and a successor, the U.S.S. Sao Paulo, which was assigned to DS9 and renamed Defiant after the loss of the original. All of this happened during the DS9 series.  In the Star Trek: First Contact movie, the Defiant participates in the opening battle, where a Borg Cube penetrates the Sol system's defenses and besieges Earth. Worf is in command, and is transported out of the crippled Defiant along with whatever's left of his crew by the Enterprise; out-of-universe, this is a rather transparent method to get Worf back into the TNG side of things after the events of ST: Generations, when he moved to DS9 as tactical officer and unofficial envoy to the Klingon Empire.  The question is, was Worf's Defiant in the movie the original, or the Sao Paulo? This would primarily depend on where the movie falls in the overall canon timeline. According to in-movie dialog, whichever one it was was salvageable and therefore would have survived the movie, so the movie would have had little impact on the canon of any running TV series at the time.


Question-related badges are too easy to get. Can we change the Popular, Notable and Famous Question badge requirements?

Question-related badges are far too easy to obtain. Badges awarded to those who ask questions greatly outweigh those which are awarded for answers. Of course, it doesn't help that there are more question-related badges, however the main culprit is the set of badges which are based on question views: Popular Question (1,000 views), Notable Question (2,500 views) and Famous Question (10,000 views).    Firstly, lets take a look at the top three  for each category (Bronze, Silver and Gold):  Gold   Famous Question (62,192) Fanatic (8,076) Great Answer (6,928)   The Famous Question badge has been awarded more times than all other Gold badges combined.  Silver   Notable Question (345,834) Yearling (231,080) Necromancer (72,875)   There are more Notable Question badges than the second-most and third-most Silver badges combined.  Bronze   Popular Question (878,622) Student (606,325) Editor (477,659)   As you can see, the view-related badges dominate all 3 badge categories by a long way.    One of the most viewed questions on StackOverflow is "" with an impressive 573,219 views, 2,410 upvotes and 1,143 favourites.  This is a famous question.  The three most recent Famous Question badges were awarded for "", "" and "".  Combined these questions amount to 30,000 views, 6 upvotes and 0 favourites. One of which is closed!  These simply aren't famous questions.    Proposed Change  I think a more fitting system would be:   Popular Question : Ask a question with 5,000 views, at least 5 upvotes and 1 favourite. Notable Question : Ask a question with 15,000 views, at least 10 upvotes and 2 favourites. Famous Question : Ask a question with 75,000 views, at least 30 upvotes and 5 favourites.


Using Primefaces 6.2 and JSF 2.3. I would like to send the visitor to a page (actually a navigation rule) in a new window (not tab) when ckicking on a menuitem. The user must be able to continue navigation in the new window. Thanks


What does ‘If she’s a feminist, then I’m a T. Rex’ mean?

There was the following  in New York Times’ (October 6) article commenting on GOP Presidential candidate, Carly Fiorina under the headline, ‘If she’s a feminist, then I’m a T. Rex’:      “Her record at Hewlett-Packard — firing skilled Americans by the   thousands and outsourcing their jobs to China and India, while almost   running her company into the ground with an ill-advised merger — is   hardly a sterling record for any sort of candidate, assuming we   actually want a president of all the people rather than a modern   Ebenezer Scrooge, - - This is a woman who would deny other women   control over their own bodies, as well. "If she’s a feminist then I’m   a T. rex.”   According to Jurassic wiki, Tyrannosaurus rex, the most famous of all dinosaurs species and commonly known as T. rex, was the largest of the Tyrannosaur family — and by extension one of the largest theropods, reaching 12 to 13 meters in length.  But what does ‘If she’s a feminist, then I’m a T. Rex’ mean? Does the writer sarcastically admit herself being anachronistic? Why should it be a T.Rex, not other monsterous or supernatural creatures, say, Moby-Dick and Godzilla?  Is this a cute turn of phrase?  Could you translate “I’m a T.rex” into plain English?