If an enemy moves and provokes an opportunity attack, where are they when the AoO happens?

I was surprised to find no mention of this in the  or : if an enemy moves from tile A to tile B and provokes an opportunity attack from me in doing so, are they in tile A or B when I perform the opportunity attack?  This is a minor detail, but pretty significant!   I'm a mundane human with a sword and threaten squares adjacent to me. If my enemy starts their turn adjacent to me then walks away out of range, do I make an opportunity attack as if they're still in range, or do I lose it because they're too far away? I have a spear with a , and I can't attack foes in adjacent squares with it. An enemy walks up to me, through my threatened range of 10 feet. When they leave my threatened tile to step up adjacent to me, do I take an opportunity attack as if they're 10 feet away, or do I lose it because they're too close? Let's say I'm Gargantuan, and an enemy wants to walk through my range. When they take the movement which provokes an opportunity attack from me, where are they when I make my opportunity attack? (Pretend it's very important: I have an ability that will cast in a straight line and might hit multiple targets or none at all, or I might inadvertently smash a pressure plate, etc)   In all cases, ignore 5-foot steps and pretend my enemy has walked far enough to provoke an opportunity attack.


today i run into another problem. i dont know how i have done it (probably i clicked sth what i should not click) - anyway - since that moment my objects are behaving totally different when i try to rotate them. the objects are now rotating around the pivot point but they keep their alignment - not sure if i am clear. eg. if u would rotate a plane which is lies flat on the ground it makes the rotation but the faces of the plane would still be up and dont which shouldn't be the case with the "normal" rotation that i know. so i want to understand what i have done (because this kind of rotation could be also usefull sometimes for me) and how can i return it in the case it happens again.


Characterization of integers which has a $2$-adic square root

Does anyone know an "elementary" proof of the following theorem?  Let $k \neq 0$ be a rational integer. Then $k$ admits a square root in $\mathbb{Z}_2$ if $k = 4^a (8b+1)$ for some $a \in \mathbb{N}$, $b \in \mathbb{Z}$.  About $p$-adic numbers I don't know anything more sophisticated than Hensel lemma. Thank you!


I am using a LaTeX template from my university to typeset my thesis. I am making references to R and I have defined a new command with:  \newcommand{\R}{R}   in order to get the roman "R". The formatting of the thesis means that chapter titles are written in a sans serif font. When I type a chapter title e.g. "\R{} source code" it does not appear in serif, rather in the same sans serif font at the rest of the title.  Is there a way to force the "base" font to be used, regardless of which font is in use at that time?  Sorry for no minimal working example - I'm just not sure which part of the preamble causes the chapter titles to be sans serif!


Allow us to access a post's Reviews directly from the post itself?

Can you give us some way to access pending Reviews for a post from the post itself?  I think this would also help improve the accuracy and quality of reviews done, as users that come across the post naturally are more likely to be better qualified to evaluate the post, and are already taking the time to understand the post's content anyways.  In most cases, these users will be able to provide better reviews than those who are  [often quickly] going through the Review Queues.  In addition, I think it would help get more reviews done, as someone viewing a post through normal site usage would be more likely to take an interest in helping maintain that post. I know I definitely would be more active with this instead of having to go through the massive Review Queue. The task of helping fix one question that I am currently reading is far more do-able than cleaning up a large queue of questions that is largely full of content I don't care about.  I'm thinking of something like a reviews(1) link that is accessible from the post itself that appears based on your rep, or perhaps even on your rep within the post's tags.


In HP, do Wizards from different nationalities have different names for spells, and if so do they have to pronounce them as such during the casting?  It seems that more veteran wizards don't seem to need to pronounce many of the spells they are casting, and whilst I am sure this has been explained somewhere, I imagine it has something to do with loading the spell with meaning/empowerment.  However, younger wizards DO seem to need to say the words of the spell they are casting, and if so how is this affected by different languages? Would a mute non-muggle be unable to qualify for wizardry, for example?


Is the chi-squared test appropriate with many small counts in a 5x2 table?

I have two sample populations, A, and B, which are independent.               A    B Ethnicity_1  1    2 Ethnicity_2  3    0 Ethnicity_4  1    0 Ethnicity_5  3    8 Ethnicity_6  15   12   In order to work out whether there is a statistically significant difference between the makeup of the samples (with a null hypothesis assuming that the two samples are the same), is the correct test to perform a chi-squared contingency table:  scipy.stats.chi2_contingency   Or, given the sizes are small, is a Fisher's exact test more appropriate - as it appears Fisher's exact test in scipy can't support bigger tables than 2x2.


So I was running around some places, and I had done lots and lots of things without saving. And then I noticed Frea was gone missing. She's carrying a lot of my stuff and I don't know her ref ID. How can i get her back?  I have all the DLC's.


While reading through a bash style guide I found the following guideline:  Math / Integer Manipulation Use ((...)) and $((...)).  a=5 b=4  # wrong if [[ $a -gt $b ]]; then     ... fi  # right if ((a > b)); then     ... fi  When I inquired about the reasoning I was told that the [[ test could potentially choke trying to compare numbers with leading zeros.  In my testing I have not been able to recreate this issue. My Question  Is there actually a functional difference between ((a > b)) and [[ "$a" -gt "$b" ]]?


Can the Polearm Master bonus attack only be used after the main attack?

The first benefit of the  feat says (PHB, p. 168):  When you take the Attack action and attack with only a glaive, halberd, quarterstaff, or spear, you can use a bonus action to make a melee attack with the opposite end of the weapon.  Does this additional attack clearly occur after the attack with the main weapon? Or is there a time to use it between the attack being "declared" and resolving the main attack? Background/motivation: I would like to attempt the following:  Announce I am attacking Bandit Keith; Use the bonus action to attack with my halberd's shaft, with a Tripping Attack maneuver; Assuming success on the attack / STR check, attack with the halberd blade at advantage;  While that appears to fit how the flow of a fight works in my head, the word take appears a bit ambiguous to me if I wish to argue from RAW. If an action is taken, does this mean it must be completely resolved?


Add number of answers to linked/related questions

When navigating the site, you can see linked and related questions at the right hand side:    The number refers to the net score of the question, whereas the color refers to whether an answer has been accepted or not (green if yes, gray if not). Yet, for those questions without accepted answers, it does not tell you whether the question has received any answer at all. This means that if you are looking for answers or if you are looking to answer questions without answers, the current system makes you visit questions which might not have answers or that might have answers, respectively. This is highly inefficient.   I think this system can be improved, by conveying more information (in particular, to indicate whether the question has answers or not).   Is it possible to add this differentiation? One option is to use a third colour (e.g. gray for those with at least one answer, white for those without answer). Another option is to add a second number in the box, like 3/2 or 3-2 or 3(2) (for a question with 3 upvotes and 2 answers). This can also be useful in questions with accepted answers. There are of course other options (e.g. add an asterisk to those without answers, 3*).   Benefits   Those who have knowledge on the topic of a question (which is presumably why they are looking at the question in the first place) can get an immediate idea of related questions which have zero answers, increasing the likelihood they might attempt to provide answers. Yes, you can also voluntary search for favourite tags with unanswered questions, but since the essence of the activity in SE is spent looking at questions, the rate of response could rise quite a lot. The same could be said of questions with just one answer, versus one with say three answers.  Those who are looking for answers to an issue might be saved considerable time by entering related/linked questions with answers only, instead of wasting time by selecting (unknowingly) unanswered questions, which they are very likely not going to answer anyway (as they are looking for answers).


Sh script not running in crontab but running manually with ./

I have a .sh script that I've put in crontab with this command:  0 * * * * /root/Linux/lansare.sh   It doesn't run even though I made the script an executable. I checked it and it has x. I tried before the script to write : #!/bin/sh but it still doesn`t run  If I run it manually like ./lansare.sh from the folder it works.  Can you please help me make it work from crontab ?   Thanks


Why does $\frac{1}{4\pi}$ appear in many formulas?

Why do most of the physical equations have $\frac{1}{4\pi}$ as constants? I have seen that many equations have $\frac{1}{4\pi}$ as constants like Coulomb, pendulum problems, etc. Can anyone tell me why is like this?


Is there any FOSS lib for reading Excel files using C

As the title says, I am looking for source code that shows how to read(write) MS Excel files in pure C (OS agnostic). I have seen some Java code (e.g. JExcel) and would use that if I can't find some existing C code with similar functionality.  What I need is to read an Excel file and convert it to XML (or some other more manageable format).  TIA


What and how does macOS Mojave implement to restrict applications access to personal data?

As well as many of the other features talked about during macOS Mojave's release like dark mode and the addition of new apps like Home, another key feature of macOS Mojave seems to be it's heightened focus on both privacy and security.   As quoted under the "Camera and Microphone Now Require Your Permission" section of  article:      Apple also announced that other categories of data, such as your Messages history and Mail database, will be protected in a similar manner to macOS Mojave's new camera and microphone permissions.   I understand that after the update, when an app requests to use your camera or microphone, you will receive an alert like the one below:    However, I am more intrigued by the following:     ...other categories of data, such as your Messages history and Mail database, will be protected in a similar manner...   I have been unable to find much information about this online and I do not currently have the pre-release version of macOS Mojave installed and am therefore unable to test this new feature but I am curious to know what exactly this feature will mean.   Has Apple publicly documented how this will work?


How to add credentials with ssh-add once, and have all shells thereonin authenticated

I am looking for a way to add my passphrase to ssh-agent using ssh-add once, and from thereonin, if I open a new shell to the machine where that ssh-agent is running, have my credentials previously added available, so I don't need to continually call ssh-add.  I am connecting from my home computer to a work vm over a vpn. My work vm's ssh key has a passphrase, and I am finding I need to enter the passphrase in every shell I open, no matter if I've already added it using ssh-add in another shell. On startup, the work vm is running ssh-agent: $ ps -ef | grep ssh-agent steve       1594    1537  0 17:17 ?        00:00:00 /usr/bin/ssh-agent /etc/X11/xinit/Xclients steve       2686    2633  0 17:29 pts/1    00:00:00 grep --color=auto ssh-agent  However, the connection details are not present in my environment: $ env | grep SSH SSH_CONNECTION=10.0.20.73 40232 10.10.0.123 22 SSH_CLIENT=10.0.20.73 40232 22 SSH_TTY=/dev/pts/1  If I run eval $(ssh-agent), then I have a 2nd ssh-agent running, and the connection details for the 2nd instance are present in my environment: $ eval $(ssh-agent) Agent pid 2705  $ ps -ef | grep ssh-agent steve       1594    1537  0 17:17 ?        00:00:00 /usr/bin/ssh-agent /etc/X11/xinit/Xclients steve       2705       1  0 17:31 ?        00:00:00 ssh-agent steve       2726    2633  0 17:31 pts/1    00:00:00 grep --color=auto ssh-agent  $ env | grep SSH SSH_AUTH_SOCK=/tmp/ssh-ScGSgVMvxvS3/agent.2704 SSH_AGENT_PID=2705 SSH_CONNECTION=10.0.20.73 40232 10.10.0.123 22 SSH_CLIENT=10.0.20.73 40232 22 SSH_TTY=/dev/pts/1  I can now successfully add my passphrase to the agent using ssh-add. $ ssh-add Enter passphrase for /home/steve/.ssh/id_rsa:  Identity added: /home/steve/.ssh/id_rsa (steve@vm-foobar)  However, if I open a new shell connection to my work vm, I am back at square one again $ ssh vm-foobar Last login: Mon Aug  3 17:29:49 2020 from 10.0.20.73  $ env | grep SSH SSH_CONNECTION=10.0.20.73 40306 10.10.0.123 22 SSH_CLIENT=10.0.20.73 40306 22 SSH_TTY=/dev/pts/2  $ ssh-add Could not open a connection to your authentication agent.  Is it possible to configure my bash profile etc on my work vm so that if I add my passphrase in one shell, it will work if I open a new shell?


Drupal 8 performance regressions. Would it be a solution for high traffic online communities?

There were some legitimate concerns about Drupal 8 potential performance regressions as a result of being built on top of Symfony2. Drupal 8 Beta-14 is the latest release; It seems that the Drupal 8 big release it comes apace. As per all the benchmarks I saw until I noticed that Drupal 8 is much slower than Drupal 7 especially for logged in users which is kind of a bummer.   Isn't Drupal supposed to be used for online communities where logged in users could interact? For displaying news and blogs there are already other software much convenient to use such as Wordpress. What kind of server would support such an expensive product? In this scenario, will be Drupal 8 a solution for high traffic online communities where logged-in users could post things and make comments and interact with each other?  Shouldn't this newer version of Drupal better than the old one? In terms of performance it doesn't seems so. This is why I'm thinking to find alternatives to Drupal for my potential clients. I'm not sure that financially speaking would worth to develop an online community website in Drupal and pay a lot for hosting and development.


In the space between galaxies in the absence of matter, would time run faster than inside a galaxy? A black hole can slow time. Is there a cosmic opposite of that effect on time? Like the following question:   If time stood still at the event horizon of a black hole (wrt an inertial observer), is there a place where time would speed up in absence of mass (again, wrt an inertial observer)? If yes, What is the fastest time can get?


Generating true curve elliptical polygons in file geodatabase using ArcPy?

As background, this question arose from trying to answer a question on   Using the ArcMap 10.1 GUI it is very easy to digitize true curve polygons into a file geodatabase feature class using the Ellipse Construction Tool but ...  Is it possible to write true curve elliptical polygons while reading rows (arcpy.da.SearchCursor) from a table containing a centre point, a major axis, a minor axis and an azimuth for each?  I had hoped that there might be a token available with  to do this, but SHAPE@ seems to be limited by what the  object supports, and that does not appear to include true curves.


Output Stream with templates c++ doesn't work

I have a template class and i want to overload the output operator <<, but my code doesn't work, I don't know why... I don't know how do the same thing, but with the input operator... Can you help me?  This is my code:  #include <iostream>  template<class TypeData, int S> class TD{   private:       int size;       int augmentation;       int capacity;        TypeData * array;        void changeCapacity();    public:     TD();      TD(const TD<TypeData,S> & array);      TypeData & operator [](int position) const;      void addElement(TypeData element);      friend std::ostream & operator << (std::ostream & output, const TD<TypeData, S> & array);      ~TD(); };  template<class TypeData, int S> TD<TypeData, S>::TD():  size(0), augmentation(S), capacity(S){     this->array = new TypeData[S]; }  template<class TypeData, int S> TD<TypeData, S>::TD(const TD<TypeData,S> & array): size (array.size), augmentation(array.augmentation), capacity(array.capacity){     this->array = new TypeData[array.capacity];      for (int i = 0; i < array.size; i++){         this->array[i] = array[i];     } }  template<class TypeData, int S> TypeData& TD<TypeData, S>::operator [](int position) const{     if (position > this->size){             return this->array[0];     }      return this->array[position]; }  template<class TypeData, int S> void TD<TypeData, S>::addElement(TypeData element){     if (this->capacity <= this->size){         TypeData * ptTmp = new TypeData[this->capacity];          for (int i = 0; i < this->size; i++){             ptTmp[i] = this->array[i];         }          delete this->array;          this->capacity += this->augmentation;         this->array = new TypeData[this->capacity];          for (int i = 0; i < this->size; i++){             this->array[i] = ptTmp[i];         }          delete[] ptTmp;     }      this->array[size] = element;     size++; }  template<class TypeData, int S> std::ostream & operator << (std::ostream & output, const TD<TypeData, S> & array){     for (int i = 0; i < array.size; i++){         output << array[i] << " - ";     }      return output; }  template<class TypeData, int S> TD<TypeData, S>::~TD(){     delete [] this->array; }   Here the main:  int main(){     TD<int,20> t;    t.addElement(5);    t.addElement(10);     std::cout << t << std::endl;     return 0; }   I have this error:  Undefined symbols for architecture x86_64: "operator<<(std::__1::basic_ostream<char, std::__1::char_traits<char> >&,  TD<int, 20> const&)", referenced from:       _main in test9-8bd618.o ld: symbol(s) not found for architecture x86_64


A non-normal variety that is regular in codimension one

So, for a projective variety $X$ over, say, an algebraically closed field $\Bbbk$, being normal implies being regular in codimension one. However, the converse is not true, in addition you require an extension property. I am looking for an example of an $X$ which is regular in codimension one, but not normal.  By common lore, this can not be a curve or a surface in $\Bbb P^3$. I was hoping that maybe there is an example of a surface in $\Bbb P^4$. Beating around the bush less: I would like a small and explicit example if possible.


Is there a form of "Anglicize" for other countries, specifically Ireland?

"Anglicize" carries the meaning of making someone or something English in form or character. However, is there a variation for this for other countries? Hence, as a foreigner living in Ireland, if my mannerisms and behaviour become more "Irish", can I say that I was "Irishcized"? How about other European countries, such as Spain, France, Poland?


How to remove all matching pattern except the top one in sed?

file.txt  1.1.1.1 abc  1.1.1.1 ccc 1.2.2.2 ddd 1.2.2.2 qqq 1.2.2.2 zzz   Expected result:  1.1.1.1 abc 1.2.2.2 ddd   I tried:  sed -i '/1.1.1.1/d' file.txt   sed -i '/2.2.2.2/d' file.txt    But however it remove all instead of leaving 1 result. How to delete all matching pattern but left 1?


Do I need to use multithreads with Tkinter?

I am learning python and this is my first experience programming with GUI. I am designing a card game in which I created a game object and graphics(tkinter) object. I designed the GUI so that when user select cards and hit submit button, the tkinter will store the selected indices and set a flag in its member variables. At the same time, I want the game object to poll the flag, if the flag is set, the game object will get selected indices and proceed to rule checking, updating, etc.  I am using a while loop in that polling and I realized that the tkinter is also using a loop somewhere so that if I run with my current code, one of the loops will be blocked(either the GUI not shown or the game not proceeding).  I could only think of using multi-threads to let the game and graphics run concurrently. But is this too complicated? is there a way to do it in a single thread or any other methods?   Thanks!


Find the GCD of a polynomial using the extended Euclidean algorithm and express it in the form $a(x)f(x)+b(x)g(x)$

I am working on a problem that I can not seem to finish. Find the gcd of $f(x)=x^7+1$ and $g(x)=x^6+x^5+x^3+1$, and express it in the form $a(x)f(x)+b(x)g(x)$ using the extended euclidean algorithm. I have performed the extended euclidean algorithm to find the following $$f(x)=(x-1)g(x)+(x^5-x^4+x^3-x+2)$$ $$g(x)=(x+2)(x^5-x^4+x^3-x+2)+(x^4-x^3+x^2-3)$$ $$x^5-x^4+x^3-x+2=(x)(x^4-x^3+x^2-3)+(2x+2)$$ $$x^4-x^3+x^2-3=(\frac{1}{2}x^3-x^2+\frac{3}{2}x-\frac{3}{2})(2x+2)+0$$ This should give us the GCD as following $$\gcd(f,g)=\gcd(x^5-x^4+x^3-x+2, 2x+2)=2x+2$$ And the monic GCD then becomes $$\gcd(f,g)=x+1$$ This is where I get stuck. Now that I have this I am not sure how to algebraically get back to the form $a(x)f(x)+b(x)g(x)$ The answer as provided in the solutions is $$\gcd(f(x),g(x))=x^4+x^3+x^2+1=xf(x)+(x^2+x+1)g(x)$$ I do not understand how to proceed and get to the answer. I have tried going backward but I am not getting anywhere. How do I go from $x+1$ to the correct solution?


I am looking for a way to view all the entries in . I have it installed already and running. By default, it shows just five recent notifications even when you have more than five in a 'list' somewhere.    Like in the screenshot above, how can I see all the 11 notifications at once?


Is $\sin(x)/x$ continuous at $x=0$,(perfectly, not tends to)? The function has right hand and left hand limit same and equals 1 but what happens at perfect zero?it should be undefined. Is it?


Duplicate source error on apt-get update

When I run apt-get update on my Ubuntu 13.10 Desktop install I get this error:  W: Duplicate sources.list entry http://dl.google.com/linux/chrome/deb/ stable/main       amd64 Packages (/var/lib/apt/lists/dl.google.com_linux_chrome_deb_dists_stable_main_binary-amd64_Packages) W: Duplicate sources.list entry http://dl.google.com/linux/chrome/deb/ stable/main i386 Packages (/var/lib/apt/lists/dl.google.com_linux_chrome_deb_dists_stable_main_binary-i386_Packages) W: You may want to run apt-get update to correct these problems   What does this mean? how can I resolve it? and what issues can it create?  I want to understand the problem So if I run into it or anyone else I can help resolve it.


I'm trying to read an Excel file (Office 2003). There is an Excel file that needs to be uploaded and its contents parsed.  Via Google, I can only find answers to these related (and insufficient topics): generating Excel files, reading Excel XML files, reading Excel CSV files, or incomplete abandoned projects. I own Office 2003 so if I need any files from there, they are available. It's installed on my box but isn't and can't be installed on my shared host.  Edit: so far all answers point to  and/or  about how to use it.


Was driving home today from a trip up north and decided to check my journey on Google's location history after I got back. Phone is a Nexus 5 running Android 5.0. The locations mostly correct apart from one obvious wild location - which is clearly impossible. Any ideas what could have happened?


Can I say, for example, "You aren't either pretty nor funny"? And if so, is it any different from saying "You aren't either pretty or funny"?


Why do far away objects appear to move slowly in comparison to nearby objects?

When we are in a moving train, nearby stationary objects appear to go backwards. In Physics, relative velocity can be employed to explain the phenomenon:      velocity of object w.r.t train = velocity of object -   velocity of train   Far away stationary objects, however, appear to move slowly in comparison to nearby objects. Here the concept of relative velocity seems to fail. Why is it so? Does it mean that relative velocity formula is also dependent on the distance between the two objects?


gcc 4.4.2 c89  I have the following enum:  enum drop_options_e {     drop_ssm,     drop_snm,     drop_ssb };   I am just wondering that is the best way to get the string representation value from the enum.  So basically, instead of returning the value of 0 for drop_ssm, I could get the 'drop_ssm' instead.  Many thanks for any advice,


Let $\mathbb{Q}[\sqrt{2}] = $ {$a + b \sqrt{2}$ | $a, b \in \mathbb{Q} $}. Prove that $\mathbb{Q}[\sqrt{2}]$ is a subfield of $\mathbb{C}$. Hint: First calculate $(a + b\sqrt{2})(a-b\sqrt{2})$  I have that $(a + b\sqrt{2})(a-b\sqrt{2}) = a^2 -2b$  I know that a subfield is a subring that is closed under inverse. However, I do not know how to prove the above.


Is maximum a posteriori estimation part of Bayesian inference?

A maximum a posteriori (MAP) estimation maximizes the posterior distribution using Bayes' rule and provides a point estimate. Is it correct to say that MAP is a Bayesian inference method? Or does 'Bayesian inference' only refer to methods that estimate the full posterior distribution (as opposed to a point estimate)?


Pluralizing a last name: Soloniewicz's, Soloniewiczs, Soloniewiczes?

Say my last name is Soloniewicz and I'm writing a holiday card. Is it:   Happy holidays from the Soloniewicz's Happy holidays from the Soloniewiczs Happy holidays from the Soloniewiczes   I'm leaning towards the number three, but looking for input.


Do there exist functions such that $f(f(x)) = -x$?

I am wondering about this. A well-known class of functions are the "involutive functions" or "involutions", which have that $f(f(x)) = x$, or, equivalently, $f(x) = f^{-1}(x)$ (with $f$ bijective).  Now, consider the "anti-involution" equation $f(f(x)) = -x$. It is possible for a function $f: \mathbb{C} \rightarrow \mathbb{C}$ to have $f(f(z)) = -z$. Take $f(z) = iz$.  But what about this functional equation $f(f(x)) = -x$ for functions $f: \mathbb{R} \rightarrow \mathbb{R}$, instead of $f: \mathbb{C} \rightarrow \mathbb{C}$? Do such functions exist? If so, can any be described or constructed? What about in the more general case of functions on arbitrary groups $G$ where $f(f(x)) = x^{-1}$ (or $-x$ for abelian groups), $f: G \rightarrow G$? Can we always get such $f$? If not, what conditions must there be on the group $G$ for such $f$ to exist?


I try to extract a file from set of .RAR parts. I always get the following error:  Corrupted   so I tried many programs to extract the corrupted RAR files. I have 10 parts, each one 400MB big. The last progam I used was .  It gave me the following message:     Severity:!High   Message:Recovery error for file XXXX with message set file   pointer error.   The program extracted 2GB of data, but it should extract 4GB.    Is there any way to extract the content or am I supposed to download the files again from another server?


From where does a photon get energy to speed up when it travels from an optically rarer medium to a denser medium?

The speed of light decreases when it travels from an optically rarer medium to a denser medium, similarly it increases back when it travels from rarer medium to a denser medium. The speed of light in glass is 2 x 10^8 m/s while in air is 3 x 10^8 m/s, from where does a photon get energy to speed up by 10^8 m/s if it travels from glass to air.


Cold fusion is being mentioned a lot lately because of some new setup that apparently works. This is an unverified claim.  See for example:         ( of that last link in the Wayback Machine, given frequent  from that page.)   While we should give the scientific community time to evaluate the set up and eventually replicate the results, there is undoubtedly some skepticism that cold fusion would work at all, because the claim is quite extraordinary.  In the past, after Fleischmann and Pons announced their cold fusion results, in perfectly good faith, they were proven wrong by subsequent experiments.  What are the experimental realities that make Fleischmann and Pons style cold fusions experiments easy to get wrong?  Would the same risks apply to this new set up?


Making automatic updated date and time field in QGIS?

I want to make a date and time updated field as I edit an attribute field in this format yyyy-mm-dd 00:00:00 (= 2016-05-08 11:04:00) - my local date/time. The data is in a QGIS 2.14 shapefile and vector lines as screenshot below. When a feature as NULL in the 'name' field, I want to enter a name for the road and the 'mod' field must receive de modified date/time like '2016-05-08 15:16:00'. I already tried some options and failed. I need help to start from beginning.  I create a new field, date/time type, but stays with NULL value after I edited, in the "name" field, or the feature itself. I used too, the expression now(), but stays with NULL value after I edited.  Note: the date seen there, 2016-04-14 is the first value created with "Field Calculator".  I am using QGIS 2.14.


If a point has no dimension and no area how can there be space?

Everyone knows that a point on any plane has zero magnitude, height, width, or volume. A line is a collection of points, and a plane is a collection of lines, while a cube is a collection of planes and so forth.  How is it then that any line, surface or cube can be made of points that have no magnitude area etc.


Is there a way to define rendering in multiple ranges in the timeline? For Example:  I like to render the scene from frame 0 to 191 and from 266 to 400. (I don't want to render from 191 to 266, because therefor I have prepared a separate scene with less objects) Is there a solution without scripting? Because I have no experience in python or any scripting language.


Bonjour.  Show that  $$\sum{\frac{1}{n^{2+\cos{n}}}}$$ is a divergent serie. $$\\$$  My main problem is: If $\epsilon$ is “infinitely small positive real number” define $A_{\epsilon}$ as the set of all $n, |2+\cos n|\leq 1+\epsilon$ $(n \in A_{\epsilon}\iff-1\leq \cos n \leq -1+\epsilon)$. The divergence should come from the sum over $A_{\epsilon}$ but I have no idea to how to handle this. $$\\$$


Bug or Feature in Audit "STOP! Look and Listen."? Answer to review in audit not visible outside audit

I just got access to the review queues (late answers). I tried to be thorough and opened the question in a new tab, since the answer I should review was odd and I thought maybe someone just copied an old comment or something. I wanted to see the whole context to write an informed comment to that answer since the user who committed it was new.  The question didn't have the answer I saw for review nor did it have any other comments on it from other reviewers and I thought: "Oh, thats weird." I waited some time and reloaded the tab with the question - the answer did not show up, so I clicked on "No action needed." (Obviously, the answer was not visible like in reviews I did previously, so why bother? And I did not skip it since I did a review after all.)  I got the      STOP! Look and Listen.      This was an audit, designed to see if you were paying attention. You   didn't pass. This answer was of very poor quality, and needed   significant improvements to be useful – passing over such posts hurts   the ability of others to find and answer good questions. Please try to   fix such posts by editing, downvoting, closing, or flagging as "very   low quality".      Don't worry, we've already handled this post appropriately – but   please take a minute to look it over closely, keeping in mind the   guidance above.   dialog.  I think that the answer to review is not shown under the question when having an audit is a bug. Or are there real situations where the item to review is not visible for the reviewer outside of the review tab?  Furthermore now I'm uncertain how to do reviews. Usually when I see a poor answer or question which was already downvoted 5 times and has 3 similar comments about poor quality I press "No action needed" too. I don't want to skip, since I did a review and I think a fourth poor quality comment does not add any more value.


Connected To Wifi Network; No Internet Acess (iPad)

On my school iPad while I had a few tabs open my internet all was all fine and handy dandy but then all of a sudden I lost wifi connection (which my iPad does pretty often so I'm angry but used to it) but when I connected to my home's wifi connection and I went back on safari to my tabs, it said my ipad isn't connected to the internet suggesting I didn't have my wifi on even though I checked and my wifi network had it's blue check mark meaning I was connected. And sometimes it would take a long moment to load it would then say  "Safari could not open the page because the server stopped responding." If I refresh the page a second time if I get this message it once more says "because your iPad is not connected to the internet." even though when I check my wifi it says I'm connected and shows the blue check mark. Even if I forget the network and renew the lease the same thing happens. I went onto Google on my computer and iPhone "wifi connected but no internet acess iPad" because I can't find the answer I need and most of the answers I don't understand. I'm only 13 years old in 8th grade jr high so I don't understand anything about stuff like DHCP or BootP or Static and how they work and I don't know what is DNS and such. I don't know exacty what resetting my network settings does and what I've read about network settings reset gets rid of stuff like VPN or MMS or APN. I'm trying to find something easy for me to understand and something helpful but not complicated that you need to be a professional coder or something to understand.  My regular iPad my family and I use, my computer (which isn't Apple) and my iPhone work perfectly fine with wifi. (Well, my iphone is new and I literally just got it yesterday and it's my first phone ever so of course no problems yet.) I tried forgetting the network after renewing the lease and that does no good either. Everytime I check the wifi network says it's connected and has the  blue checkmark and even the little lock icon but it always says it's not connected when I reload the page on safari. Can someone please explain exactly what's going on but explain in a way a jr high student girl (who doesn't know the complicated stuff and difficult steps to fixing issues like these well at all) like me can understand?  (Oh, and I apologize for any grammar mistakes and whatnot just to say before I start feeling guilty over them afterwards in case I made any.) I'd really love the help! In case I need to include info on the school iPad, it's a iPad air with the 9.2.1 software update and IOS 8.  Just including this info in case it's important!


How do I update Drupal core on composer install?

I installed (or downloaded) drupal 8 via:  composer create-project drupal/drupal my_site_name 8.0.*  Which, at the time I ran it, downloaded Drupal 8.0.1.  Now drupal 8.0.2 is available and I'd like to update to this version.  I'm not sure how to update core but I decided to try running composer update from my drupal site's root directory.  This updates many packages (e.g.):  $ composer update Loading composer repositories with package information Updating dependencies (including require-dev)   - Removing composer/installers (v1.0.21)   - Installing composer/installers (v1.0.22)     Loading from cache  > Drupal\Core\Composer\Composer::vendorTestCodeCleanup   - Removing symfony/class-loader (v2.7.6)   - Installing symfony/class-loader (v2.7.9)     Downloading: 100%  > Drupal\Core\Composer\Composer::vendorTestCodeCleanup   - Removing symfony/console (v2.7.6)   - Installing symfony/console (v2.7.9)     Downloading: 100%  (...)  > Drupal\Core\Composer\Composer::vendorTestCodeCleanup   - Removing twig/twig (v1.23.1)   - Installing twig/twig (v1.23.3)     Downloading: 100%   However I don't see anything about updating drupal/drupal.  And when I visit my site's status report it still shows 8.0.1.  So how do I actually update core via composer?


I think my gnome-panel is messed up because I alt+right click it and nothing pops up.  I'm on 12.04, classic gnome desktop.  so I used locate and found gnome-panel in .gconf somewhere, how do I clear just gnome-panel's settings so that I can add things to my panel again?   edit:  matt: ~/.gconf $ find|grep -iw panel ./desktop/ibus/panel ./desktop/ibus/panel/%gconf.xml ./apps/gnome-settings/gnome-panel ./apps/gnome-settings/gnome-panel/%gconf.xml


Is $\mathbb{Z}[\sqrt{-7}]$ a UFD or not? I feel like there should be some easy example showing that it is not, but I can not think of one.


Poor performance after reinstalling to a USB drive

I am currently running Ubuntu 11.10 off of a SanDisk 16GB USB. I installed it using a Live USB with the following partition configuration:  6GB Primary /dos   FAT32 5GB Logical /      ext4 5GB Logical /home  ext4   I don't have a hard disk, and don't see myself getting one anytime soon.   I rely solely on this 16GB, and two other 4GB USBs, one of which I used as the LiveUSB. I bring the USBs around, and even use the install at work.   I previously used an install that used a swap file. It functioned fine for the most part, save for a few slow moments, but I came across , and it got me thinking about my USB's life, so I reinstalled with the current config.   My problem now is that it is slower. Applications like Firefox would hang more often. In my previous setup (the automatically partitioned setup), Firefox would start hanging if I was running an unzip or install task on the same partition as /.   Now however, it would hang if I had another window open i.e. the system settings window. My guess is that it may have something to do with the swap file or the install being on a Logical partition rather than a Primary partition, but I don't know.   Any insight as to why it has slowed down?


How to install Nvidia Geforce GTX 960 Driver

Im new to Ubuntu, eveything is working great so far, except i can't seem to install the right driver for my Nvidia Geforce GTX 960 SSC. I'm trying to play steam games and can't get the right driver. Any help would be appreciated.


How to rename archives in Ubuntu's terminal?


Using \show in nonstopmode causes TeXmaker to raise false alarms. Any fix?

I'm currently reading the TeXbook, and I use \show a lot to see how Knuth defined plain-TeX macros in terms of TeX primitives. For instance, to have access to the definition of \centerline, I would write \show\centerline in my input file. When I compile  that file with pdftex in interactive mode from the command line (a Unix terminal, in my case), TeX generates an error message that shows me the definition of \centerline in the terminal and offers me a menu of options (as described in Chapter 6: Running TeX in the TeXbook).  I understand that design choice by Knuth of having TeX generate an error message for each instance of \show: he probably wanted to leave the user some time to read what \show... prints in the terminal before letting TeX resume execution, instead of having to open the log file only after the end of the compilation.  However, instances of \show... in the input file have the undesirable side-effect of raising "errors" (false alarms, really) when pdftex is called from within an IDE such as TeXmaker with option -interaction=nonstopmode. For example,  \show\centerline \bye   when compiled with pdftex -interaction=nonstopmode causes TeXmaker to report     Obviously, those false alarms prove really annoying when debugging. I always have to ask myself: Wait... are those errors due to instances of \show in my input file, or are they bona fide errors? On the other hand, my understanding is that you have to specify  -interaction=nonstopmode   if you want to call pdftex from within an IDE. Therefore, my question is:  Is there any way of preventing TeXmaker from reporting those "false alarms"?  Note: the problem I describe may be present in IDEs other than TeXmaker as well.


Prove that any two cyclic groups of the same order are isomorphic

Prove that any two cylic groups of the same ordr are isomorphic


Prove that every elementary matrix is invertible, and the inverse is again an elementary matrix.

I know that there are many proofs regarding this. However, the book i'm using seems to suggest another way to do it without giving an answer. What i mean by the another way is some other proofs that do not use the fact that elementary row operation can be expressed by multiplying elementary matrices. The book says that the lemma need to be proved only when the size of identity matrix is 2 by 2. Does it have something to do with mathematical induction? That is, did the author want us to find out both induction hypothesis and induction step?


I'd like to be able to open a TDataSet asynchronously in its own thread so that the main VCL thread can continue until that's done, and then have the main VCL thread read from that TDataSet afterwards. I've done some experimenting and have gotten into some very weird situations, so I'm wondering if anyone has done this before.  I've seen some sample apps where a TDataSet is created in a separate thread, it's opened and then data is read from it, but that's all done in the separate thread. I'm wondering if it's safe to read from the TDataSet from the main VCL thread after the other thread opens the data source.  I'm doing Win32 programming in Delphi 7, using TmySQLQuery from  as my TDataSet descendant.


How can I give space " " as input in shell script ?  Ex :   echo " Enter date for grep... Ex: Oct  6 [***Double space is important for single date***] (or) Oct 12 " read mdate  echo $mdate   I get the output as Oct 6 but I want Oct  6.


How change the label “Listing” into “Code”?

I'm new with LaTeX and now I have a problem with a reference of the C++ code.  I have this code:  \begin{lstlisting}[label={code:enumtx}, caption={Porzione di codice che riporta il tipo enumerazione nel file standard.h di bitcoin core.}] enum txnouttype {     TX_NONSTANDARD,     TX_PUBKEY,     TX_PUBKEYHASH,     TX_SCRIPTHASH,     TX_MULTISIG,     TX_NULL_DATA, //!< unspendable OP_RETURN script that carries data     TX_WITNESS_V0_SCRIPTHASH,     TX_WITNESS_V0_KEYHASH,     TX_WITNESS_UNKNOWN, //!< Only for Witness versions not already defined above }; \end{lstlisting}   and this result     My question is:  How can I change the caption title from Listing 2.1 to Code 2.1? Is this possible?  This is a minimal example:  \documentclass[12pt]{toptesi}  \usepackage[utf8]{inputenc} %utf8 \usepackage[italian]{babel} \usepackage{listings}   \lstset{%     captionpos=b,     language=C++,     basicstyle =\small\ttfamily,     keywordstyle=\color{red}\bfseries,     breaklines=true,     breakatwhitespace=true,     frame=lines,     numbers=left,     numberstyle=\footnotesize, }  \begin{document}  \begin{lstlisting}[label={code:enumtx}, caption={Porzione di codice che riporta il tipo enumerazione nel file standard.h di bitcoin core.}]  enum txnouttype {     TX_NONSTANDARD,     TX_PUBKEY,     TX_PUBKEYHASH,     TX_SCRIPTHASH,     TX_MULTISIG,     TX_NULL_DATA, //!< unspendable OP_RETURN script that carries data     TX_WITNESS_V0_SCRIPTHASH,     TX_WITNESS_V0_KEYHASH,     TX_WITNESS_UNKNOWN, //!< Only for Witness versions not already defined above }; \end{lstlisting}  \end{document}


So I need to count how many Eulerian cycles exist in the complete graph $K_{n,2}$. Two cycles are considered identical if:  1) The order of the edges is identical in both cycles. For example: The cycles $cabc, bcab, abca$ are identical.  Or  2) If we get the first cycle by reversing the order of the edges in the second cycle. For example: $abca$ and $acba$ are the same cycle.  Note: The order of the edges is what matters, not the vertices. Also, of course if $n$ is odd, there's no such cycle.  So I tried this in different ways and arrived at different solutions:  I can think of this as all the permutations of the side with $n$ vertices, removing all the reverse permutations, so that's $\frac {n!}{2}$.  Or, I can think of it as permutations in a cycle, which means $\frac {(n-1)!}{2}$.  Then I manually counted the Eulerian cycles in $K_{2,4}$ and I got 6, which works well with $(n-1)!$. So either I counted incorrectly, or $(n-1)!$ is the answer, but I don't understand why.  Any help would be appreciated.


How do I use a Macro Lens for Jewelry Photography?

I've been looking to upgrade the camera I use at my job. Thinking of getting the Sony a6000. We list things on ebay to sell, and quite frankly I just don't like the lightbox, nor the camera we currently have.  We're using a Nikon D3100, and I forgot the name of the Macro Lens.  Basically, I want to have my own personal camera, that's better than the D3100, but one I can use at the job as well for when we photograph our jewelry.  I do mainly macro photography in the lightbox, and I'm working on my own setup with better lighting and other things to improve our photos. I just ordered an external flash for the D3100 so I can over expose the background to get a nice white one with the pics when I finish my own setup as well, but I digress lol.  I need suggestions for what I should look for in a good macro lens to use when I photograph jewelry. I mainly work with rings, but I also do pictures of pendants/charms, necklaces, bracelets, watches, and other related items too.  Right now I'm considering the SEL30M35. But I haven't bought anything yet (Including the new camera)  To get a better idea of the type of photos that I'm producing with the Nikon, you can check these out: (I don't have the stats for the Aperture, Shutter Speed, ISO, etc)       You can see that when you're 100% zoomed in, things aren't that detailed. Don't get me wrong I've had some nice shots. But that ugly grey background usually says otherwise. I use different backdrops in the cases when the background looks too ugly. I take all my pics handheld, Manual Mode, the focusing is Auto Manual (focuses when I hold the shutter release halfway) and when I'm at the lightbox the rings are only about 5 - 8 inches away, unless I bring them closer to get detailed diamond shots. (Which, I might add, aren't too good.)  I want to get some photos as close to these as possible:       I'm still an amateur, and I'm still learning, but I really want to take better photos. I'd love for them to be sharp and really detailed on most parts of the subject. That and seeing the photos on an LCD screen with the a6000 before actually snapping them to have a look would save me a lot of time.  Merging some of the macro shots to get everything in focus (I think its called focus stacking), and to use focus peaking on the new camera would probably help me a lot more as well. That and a lot better lighting than the lightbox gives off.  Heck, maybe these photos are actually good and I'm just too picky lol, idk.  Anyway, what do you guys think? Would the SEL30M35 macro lens be a good lens for my needs with the jewelry photography I'm trying to do? I understand some lenses aren't compatible with the auto focus or something like that on the a6000 (maybe the E-mount?). How can I be sure they're compatible? Or if I need an adapter, can you suggest one as well?


Python: Efficient way of having ternary operator

I tried to find best way of having ternary operator in python, but didn't find conclusive information. Is using lambda, as shown below, the best way? What is the best way to do below operation in one line?  return (lambda: "Yes", lambda: "No") ['hello' == 'hello']()


External hard drive only opened by one computer

Can I make it so my external hard drive will only open on my devices. Maybe an app that will restrict access?


How to find the lp-name and ppa-name on launchpad to add with add-apt-repository?

My goal is to install the libraw5 package. It is not a part of the standard Ubuntu packages already installed on my PC. I learned so far, that I have to search for this package on launchpad.net. There, I should find two important informations:    The name of the Launchpad-user The PPA-name   Once I obtained these two informations I have to write into the shell:  add-apt-repository ppa:launchpad-user-name/ppa-name   I opened the site on launchpad.net and wrote the name of the package into the search bar. Unfortunately I can not find any hint for the launchpad-user-name and the ppa-name. Where to find them on this site?


how to recover a deletd ext4 GPT partition on one drive, from a DD'ed 2nd drive that was RM -RF'ed

good day to all!  I goofed.  In prepping for a migration .. I DD'ed a drive to another spare to have a backup of the files.  Then I booted next weekend not knowing that I mounted the 2nd DD'ed backup drive (due to duplicate UUID's ... dummy me).  I did some small work thinking it was on the primary drive not the backup.  I then did RM-rf on one drive ... removed what I thought was the good drive ... rebooted ... and deleted the partition on the second drive thinking it was the 1st.  I have since learned not to DD a drive and leave it in there for the next boot.  Trouble is: ... I have one drive with the partition but RM-rf all files of my /home ... ... and another drive with the files intact but the partition deleted.  I would be happy with either due to the small amount of work done.  How do I get the partition data from the drive that was only RM -rf ... and restore it to the other drive that only had the partition deleted?  ... or should I try to un-delete the data one the drive that was RM-rf?  18.04.1 Ubuntu.  Thanks!


I received a retention bonus during the tax year 18, with the clause that if I leave within the year I have to pay back the full amount. I will hand in my resignation and will have to pay back bonus prior to tax day. After that I will leave the country and as such have to file a partial tax return. For both years I'm not a citizen but a residence for tax purposes (already filled for a few years).  I plan to hand in both my partial 19 and full 18 tax return at the same time. How would I handle the bonus received in 18 and returned in 19?  I'm not sure  answers my case, as I'm asking for a partial tax return (19) and I already will have payed back the amount once I hand in the 18 return. The amount is over $3k.


I have a CentOS7 Server running slapd 2.4.44 and I'd like to modify the default hashing algorithm being used. Instead of using SSHA, i'd like to use SHA-256 or SHA-512.  I've been having trouble finding documentation on this and I'd like to ask if anyone can provide a link to any resources to put me on the right track.  I've read a few articles that mentioned using CRYPT to instruct OpenLDAP to use a strong encryption scheme but bash returns an error when I try those commands.   For example, I entered the following at the terminal..  password-hash {CRYPT} password-crypt-salt-format "$6$%.16s"  "bash: password-hash: command not found..."  Is there a file I should be modifying instead?  Thanks!


How many times is it safe to reheat chicken?

I thought I remembered hearing the food agency  say that you should never reheat chicken meat after the initial cooking. However, I cannot find the statement of it anymore. Now I'm starting to suspect my memory.  Could this statement be true?  Is it unsafe to reheat chicken?


Post-Invoke-Success if /usr/bin/test -w /var/lib/command-not-found/

When I ran sudo apt update I got this error.  Problem executing scripts APT::Update::Post-Invoke-Success   'if /usr/bin/test -w /var/lib/command-not-found/ -a -e /usr/lib/cnf-update-db;  then /usr/lib/cnf-update-db > /dev/null; fi'      E: Sub-process returned an error code     I have searched it on Google and found nothing the same thing. Before that I changed my repository to http://kambing.ui.ac.id.


example of a gluable unseparated presheaf

Let $X$ be a topological space. Is there an expample of a presheaf $\mathcal{F}$ which satisfies the glueing axiom, but is not separated?   Note that I use the terminology of wikipedia, see


On international SO sites, migrated questions get the [discussion] tag even though this is a synonym of another one?

I noticed in both Stack Overflow en español and Stack Overflow em Português a bug that may be related to the fact that some default tags are made synonyms to others.  Once a question is posted in the main site and gets migrated into Meta, it gets the  tag. This is OK by definition. However, in those sites that tag is a synonym to either  (in SOes) or  (in SOpt). For this, the question should get the principal, translated tag instead of discussion.  Examples:    in SOes  in SOpt   Note: , but now I am reporting it here since I saw it happening in Meta SOpt as well.


I'm downloading an  file via a torrent, but my anti-virus detects something. Is it possible that the AVI file contains a virus?  It is quite weird since the torrent has many positive reviews.


How to maximise contrast range of distant landscapes with blue haze?

Distant landscapes often appear hazy, washed-out and blue due to .  What can be done to maximise the contrast range of the exposure when photographing such scenes?  For example:   Would any sort of hardware, camera settings, or type of "film" (including digital) produce better results? Are there reliable ways to predict when haze will be lowest?


On the latest iOS StackExchange app, math symbols are not rendered at all in the titles and comments, while they work properly on the website. It's often useful to see, at a glance, what a question is about by looking at the math in the title, and comments are hard to read without the MathJax rendering. Is anyone working on this?


A first-countable, compact space which is non-separable

Let $X$ be a space which is first countable and compact. Is $X$ necessarily separable?  Is $X$ necessarily second countable?


Not "irony" or "hyperbole" - is it just "joke"?

Is there a word that describes a saying which states one thing in order to make the point (clearly known by all) that the opposite is true? For example, my brother is sitting in front of a once-full-now-empty plate, and I say, "You weren't hungry, were you?!"


application for uk visa after 10 years ban expires

is there any one that has applied to the uk embassy after given the 10 years ban and the ban expires? I want to know what the chances are. Thanks


Does deleting a photo from iCloud on PC affect its copy on iPhone storage?

I want to ask if I delete a pic from iCloud online, does it get deleted from the iPhone too?


My structure begin on section (this is a monograph with documentclass article), so I don't use \chapter.  I have one section with I need expand to 'level 6' (as a precaution, expand to 'level 10').  Example:  1.  1.1.  1.1.1.  1.1.1.1.  1.1.1.1.1.  ...  1.1.1.1.1.1.1.1.1.1.  How can I do that without change too much the structure?  P.S: I try this (great) suggestion (), but he needed chapter to begin.


How to solve this rotational mechanics problem?

I was doing this problem for self study in rotational dynamics:     Two discs are mounted on thin, lightweight rods oriented through their centers and normal to the discs. These axles are constrained to be vertical at all times, and the discs can pivot frictionlessly on the rods. The discs have identical thickness and are made of the same material, but have differing radii $p$ and $q$. The discs are given angular velocities of magnitudes $x$ and $y$, respectively, and brought into contact at their edges. After the discs interact via friction it is found that both discs come exactly to a halt. Which of the following must hold? Ignore effects associated with the vertical rods.   Answer choices:   $(x^2)p = (y^2)q$ $xp = yq$ $x(p^2) = y(q^2)$ $x(p^3) = y(q^3)$ $x(p^4) = y(p^4)$   I got the answer $x(p^4) = y(p^4)$ by setting the angular momentum of the two discs equal to each other (because of conservation of momentum) and solving, but the answer is $x(p^3) = y(q^3)$. How do I solve this problem?


Suppose $f_n\to f$ in $L^1([0,1],\lambda)$. Prove or disprove: $\exists \{f_{n_j}\}$ such that $f_{n_j}(x)\to f(x)$ for almost every $x\in[0,1]$.

This is part of an old preliminary exam in Analysis I am reviewing to prepare for my own prelim. $\lambda$ is the Lebesgue measure. $f_n\to f$ with respect to the $L^1-$norm.  I know that there exists at most a subsequence fulfilling the condition, since, e.g., we could have $f=0$ and $f_n=0$ except at $q_n$, with $q_n$ cycling through the rational numbers (with each rational number appearing infinitely often). Then $f_n\to f$ but it is not the case that $f_n(x)\to f(x)$ for almost every $x\in[0,1]$. It's obvious in this example that there will exist a subsequence fulfilling the condition, and I feel confident that there will always be such a subsequence. That is, I think the answer is to "prove", not "disprove". But I'm having difficulty seeing how to prove it.  This is a case where I feel like I understand the problem but can't quite figure out how to structure a proof. Every attempt I've made has become overly convoluted and I've become confused. Any help would be appreciated.


I need to install eclipse for school, so that I could help with an Android project. Everyone else at my school uses Windows , so they cannot help me. I am using Ubuntu 18.04 and this fails to install the package: sudo apt-get update sudo apt-get upgrade sudo apt-get install eclipse  Here is the error I'm getting: Reading package lists... Done Building dependency tree        Reading state information... Done Package eclipse 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 'eclipse' has no installation candidate  I've searched for an answer, but nothing seems to help. Would anybody mind helping me?


Where can I ask about payment processors for use in a website?

I want to ask about payment processors for use in a website. The one I found on Stack Overflow was closed because it's off-topic. None of the others automatically lend themselves to this question. Any ideas?


Minimising number of dynamic pages to map scattered points using ArcGIS Desktop?

From time to time I have to produce mapbook to show points of interest. First step to create pages, using regular mesh:    I don't like the solution because a) there are some pages with single points (e.g. page 25) sitting on the edge and b) too many pages.  First issue is easy to fix using code, - move rectangle of page extent to center of relevant points extent:    I still don't like it, it looks very crowded because number of pages remains the same.  Remember, they all end up being actual A3 paper pages in multiple copies of report !.  So I've cooked a code that reduce number of pages. In this example from 45 to 34.    I am not sure if this the best result that can be achieved,  What is the best strategy (pseudo code, publication, Python library) to shuffle through points in order to minimise number of given size rectangles to capture all of the points? Surely, someone discovered it in game theory, military art or fishing industry  This is update to original question:  This shows real extent and page size required:    Closer zoom showing 10 out of 164 pages:      Rectangle size can change as soon as it stays within the limits, i.e. smaller is fine.


Block internet for a specific user, permanently

works:  sudo iptables -A OUTPUT -m owner --uid-owner {USERNAME} -j REJECT   to block internet for a specific user. But it's not permanent.  What's the easiest way to make this persistent after a reboot, with newer systems (with systemd)?  Creating a specific .service file is always tricky and takes some time to figure out: one-shot? stoppable? forking? etc. and , so I was wondering what is the most natural way to persist a iptables rule with new systems.


Is a transit visa required in Stockholm for a resident permit holder of Norway?

I am travelling from India to Oslo, Norway on a resident permit. I have a transit at Stockholm, Sweden. Do I need a transit visa for the same travel?


How to minimize salt taste from biryani?

I've tried Veg Biryani dish yesterday but I was failed to know the amount of salt to be added. Its tasting little bit salty. I've to cook it again today night. Can somebody tell me how to reduce the salty taste in case Veg Biryani or any dish?  For person who don't know Veg Biryani:


If statement does not print out the body when the condition has met

I expect the output will be the string in the wordList when it matched the search before the for loop exits but it does not print out every time when the if statements met the condition.  search = "ABC"  wordList = [["ABC", "123"], ["ABC", "456"], ["DEF", "123"]]  public void biDi(String searchWord, String[][] wordList) {     int start = 0;      int end = list.size ()-1;     String search = searchWord;      int path = 0;     for (int i = 0; (i < (list.size ()/2)); i++) {         if (search == wordList[start][0]) {             System.out.println (wordList[start][1]);         }         if (search == wordList[end][0]) {             System.out.println (wordList[end][1]);         }          start++;         end--;         path++;     }      System.out.println (path);  }


(Why) Has Kohonen-style SOM fallen out of favor?

As far as I can tell, Kohonen-style SOMs had a peak back around 2005 and haven't seen as much favor recently. I haven't found any paper that says that SOMs have been subsumed by another method, or proven equivalent to something else (at higher dimensions, anyhow). But it seems like tSNE and other methods get a lot more ink now-a-days, for example in Wikipedia, or in SciKit Learn, and SOM is mentioned more as a historical method.  (Actually, a Wikipedia article seems to indicate that SOMs continue to have certain advantages over competitors, but it's also the shortest entry in the list. EDIT: Per gung's request, one of the articles that I'm thinking about is: . Note that SOM has less written about it than the other methods. I can't find the article that mentioned an advantage that SOMs seem to retain over most other methods.)  Any insights? Someone else asked why SOMs are not being used, and got references from a while ago, and I have found proceedings from SOM conferences, but was wondering if the rise of SVMs or tSNE, et al, just eclipsed SOMs in pop machine learning.  EDIT 2: By pure coincidence, I was just reading a 2008 survey on nonlinear dimensionality reduction this evening, and for examples it mentions only: Isomap (2000), locally linear embedding (LLE) (2000), Hessian LLE (2003), Laplacian eigenmaps (2003), and semidefinite embedding (SDE) (2004).


How can I convert a Lead to an Opportunity via the REST API for a Connected App?

I have a connected app, which authenticates with Salesforce using REST API via OAuth. How can I convert a Lead to an Account/Opportunity etc? There was some previous solution mentioning Apex, but this is a connected app, and I need a way I can perform this conversion for other organizations (our customers) without having to perform any custom action on their part (other than the OAuth step).  Thanks!


I'm considering attaching a new towel rail to the drywall in my bathroom, with attachment points approximately marked by the yellow postit notes in this picture.    This is on the 21st floor of a condo building in Montreal (built in 2014). The building manager said the drywall is approximately 1" thick (a full inch! not a centimeter).   Is this really possible? (I haven't been able to get confirmation from anyone else). If the drywall is really 1" thick, will the usual drywall anchors be effective? Usually the pictures I see of drywall anchors have them exceed the thickness of the drywall by around 1/2", and have expanders which end up significantly expanded after the screw is inserted. However, most anchors are at most 1" long, and in a 1" thick drywall, there probably won't be much room for the expanders to expand. Will this decrease the effectiveness of the anchors? Another issue is the nearby thermostat/light switches. How do I make sure to avoid any of their wiring when drilling in the drywall anchors? Is it important to avoid them? Part of this I suppose comes down to how the wires are arranged behind thew all. Will they for example come bundled in a metal tube? (In this case hitting the metal tube may cause the tube to flex undesirably? Is there anything else I need to watch for? How can I tell if there's plumbing behind the wall? If I gently drill a small hole, poke into the hole with a toothpick and check there's nothing within an inch behind the wall to worry about, is that a guarantee I'll be fine?


What’s the quickest way to get diamonds?

I wanted to know, what’s the quickest way to get diamonds? I want to start a survival world, but I want to be able to get diamonds quickly. Please share the quickest ways you found!


How to turn all stone to TNT in Minecraft

I really want to do a prank where I turn all stone to TNT. That way, in lava lakes the TNT will blow up. I just need to figure out how to do it. Which would it be best to use?   /fill /replaceitem  /blockdata /setblock something else?


How do you calculate damage for MM1 and MM2 monsters?

I realize this may be a subjective question, but I'd really like to know what the consensus is. I know that WotC changed the way they calculate monster damage from MM3 and onwards, but there's isn't much errata for the first books. So:  Do I use the old damage values?   Do I completely recalculate the numbers based on their tables?  Do I double the non-rolled damage?  Do I use some other method?


Possible typo in problem of Braun's Differential Equations

In Martin Braun's book Differential Equations, problem 16 in section 1.10 says:  Consider the initial-value problem $y'= t^2+y^2$, $y(0)=0$ ... (*)  and Iet $R$ be the rectangle $0\leq t \leq a, - b \leq y \leq b$  (a) Show that the solution $y(t)$ of (*) exists for $0 \leq t \leq min(a, b/(a^2+b^2))$  (b) Show that the maximum value of $b/(a^2 +b^2)$, for a fixed $a$, is $1/2a$.  (c) Show that $\alpha=min(a,\frac{1}{2}a)$ is largest when $a=\frac{1}{2^{1/2}}$.  (d) Conclude that the solution $y ( t)$ of (*) exists for $0 \leq t \leq \frac{1}{2^{1/2}} $  The problem is, in the incise b) i proof by calculus of the maximum of the function $f(b)=\frac{a^2}{a^2+b^2}$, the maximun is reached when $f(a)=\dfrac{1}{2a}$, but in incise c) the book puts $\alpha=min(a,\frac{1}{2}a)$, my question is, that is an error? or i'm wrong? it should be $\alpha=min(a,\frac{1}{2a})$? or not? and, how can i prove that? thanks and, i apologize if the question is clumsy, but i tried to solve this problem for hours and the book confused me, because the notation.


What are they monitoring to determine that Solo is still alive?

As everyone knows, in 'Empire Strikes Back' they freeze Han Solo by using carbonite. We then see Lando Calrissian check the side of the carbonite block which has a heap of lights and buttons, which tells him he was still alive after the freezing process.    My question is, what is the in-universe explanation as to how they were getting life signs from Han while being frozen solid in carbonite.


I am confused about the usage of the present simple in the future tense. Doesn't it refer only to schedules? The following example deviates from this rule.  We’re on holiday in Paris next week. (Taken from English File Pre-Intermediate SB)  Shouldn't it be: We will be/are going to be in Paris next week?  Thanks in advance for your contribution :)


I unfortunately got a very poor and cheap 18-55mm lens on my Canon 60D. In addition to poor quality of my photos (poor in comparison with my 50mm f/1.8 Lens which makes great pictures) the noise level of my pictures is really high.  Should I upgrade my camera or get a better lens? since I'm interested in "night sky photography" this level of noise is really bothering.  For example you're taking photo of a special scene with two different lenses with the same ISO, Aperture and Shutter speed. Is the noise level of a photo taken with Zeiss Lens the same as Canon Lens?


I am a Moroccan citizen flying from Casablanca to New York via Lisbon (TAP Portugal). The layover is around 8 hours at Lisbon and I have no Schengen visa of any type.    Do I need an airport transit / transit visa for Lisbon?


rigid body simulation - unwated spaces between objects

I've been trying to play with a rigid body simulations.  I prepared a project of a building made of domino tails. I've placed all objects very tight, but as soon as I start animation it looks like there was some tiny gap between objects, so they all fall down a little bit. For a high building it leads to a construction disaster as the whole building colapses.  Here is an example:  (I'd suggest to use 0.25x speed).  How can I fix it?


If $F/k$ normal, $g,h \in F[X]$ monic irreducible factors of $f \in k[X]$, then $\exists\ \sigma \in Aut(F/k)$ s.t. $g^\sigma = h$.

This is Exercise 26 from Chapter V Algebraic Extensions in Lang's Algebra.  $F$ is finite normal extension over $k$ and $f(x)$ is irreducible in $k[x]$. If $f(x)=g(x)h(x)k(x) \in F[x]$ where $g(x),h(x)$ are monic irreducible factors in $F[x]$, I need to show that there exists an automorphism of $F$ which takes $g(x)$ to $h(x)$.  Any hints would be appreciated.  Sending one root to another is okay but how to do that for a collection of roots?


How to replace missing icons with another icon-pack?

Is there a way to replace missing icons with icons in another pack we prefer instead of Hi-Color that Ubuntu uses by default?


How to get rid of an already applied solidify modifer

When starting scuplting I accidentally applied the solidify modifer to my mesh, apart from creating unnessecary geometry it also caused problems with inner vertices sticking out of the mesh.Is there a way to remove the inner layers of vertices ?


A book where an special mission crew is made of aliens and humans with special skills

Someone is gathering a crew with aliens from different planets (including humans), and between them there is a woman whose special skill is extreme luck.  Sorry, no more details except I picked up the book from a list of top classical sci-fi books.


Cartoon where a group of 3 go around fighting rival teams with magical powers

This cartoon is animated and not in CGI or old animation like the 90s. I think it was made in 2009-2014 by Cartoon Network or Kix. The only things I know is that the cartoon involves a group of 3 people who have magical powers (the team consist of 2 boys and 1 girl and an orange alien with an antenna). One of the boys has blond hair and white and the girl is dark-skinned. They go around fighting rival teams with their magic and in the second fight they turn into the magical creatures they gained their powers from. I remember the blond character saying "freeze ray- what the, freeze ray is a blue attack not a green attack" and the girl character says "you can't hit what you can't see- ha missed". I remember the orange alien saying "don't eat me- I'm sweaty and my antenna is chewy". I remember the characters saying the name of the creature and rising up into the air with the image of the creatures behind them (this is in the first fights they do and in the second fights they turn into their creatures) The orange alien character can use this "magic" as well but he only does it for one or two episodes (one of the rival team characters who is female turns into a spider during their fights).


Where can I find a citable reference for the formula for inverse distributions?

To be more specific: Let the random variable X be distributed according to probability density function f(x). Then the pdf of Y=1/X is given by g(y)=1/y^2 f(1/y), .  I wonder if there is any citable reference for that. Or is it common knowledge? I'm coming from a different field of mathematics and lack some background in statistics. I looked through some text books, but didn't find any mention of it yet.  Thanks a lot!


Why is there a 40 minutes time limit for posting questions

This is a follow up question to this question:    Why is there a limit for people under 124 rep? As long as there's a limit for number of questions per day, what does it matter if people ask them after 40 minutes or seconds?


Issue when comparing String and variable in an else-if loop

I have an else-if loop that compares a variable to a String letter, but it does not seem to detect any matches. My code is as follows:  public static void useMove(String move){     System.out.println(move);     System.out.println(move.getClass().getName());     if(move == "N"){         GLObject.MOVE('N');     }     else if(move == "E"){         GLObject.MOVE('E');     }     else if(move == "S"){         System.out.println("GOT HERE");         GLObject.MOVE('S');     }     else if(move == "W"){         GLObject.MOVE('W');     }     else if(move == "HELLO"){         GLObject.HELLO();     }     else if(move == "PICKUP"){         GLObject.PICKUP();     }     else if(move == "LOOK"){         GLObject.LOOK();     }     else if(move == "QUIT"){         GLObject.QUIT();     } }   If I enter the value of move as the String "S" it does not detect that move is equal to "S". So the output I get is:  S java.lang.String   Can anyone advise as to what the problem is?  Thanks very much.


Finding solutions of equation without using inequalities.

The problem is as follows:      Find the unique ordered triple of positive integers $(a,b,c)$ with   $a\leq b\leq c$ such that      $$\frac{1}{a}+\frac{1}{ab}+\frac{1}{abc}=\frac{25}{84}$$   The problem is easy to solve by first bounding $a$, then bounding $b$ and finally $c$. This is the solution I was given:  It's obvious that $a\geq 4$, otherwise $\frac{1}{ab}+\frac{1}{abc}$ would have to be negative, which we don't want. We also have  $$\frac{25}{84}=\frac{1}{a}+\frac{1}{ab}+\frac{1}{abc}\leq \frac{1}{a}+\frac{1}{a^2}+\frac{1}{a^3}=\frac{1+a+a^2}{a^3}$$  $$\frac{25}{84}\leq \frac{1+a+a^2}{a^3}$$  so $a\leq 4$ in order to satisfy the inequality, hence $a=4$. We can proceed in a similar manner to solve the rest of the problem.   Yes, this solution is simple and beautiful, but suppose I just want to solve this problem using a rigorous number-theoretic method (e.g. without inequalities). How would I go about doing this?  *EDIT* By the way, this problem was from part C of the 2013 COMC.


Is there a Poset which has one maximal element but no greatest element?

If there is exactly one maximal element, then shouldn't that element also be the greatest element of that Poset?


I am trying to prove that ($\forall \ n\in\mathbb{N}$) there exists a prime number $q$ such that $n < q \le 1 + n!$  I have made a graph with $n=0$ through $n=10$ and found solutions to all of them looking for a pattern and I see that $n!$ gets enormous fast and it becomes quite obvious that there is a prime number in between them.    I have considered trying to prove by contradiction that $q$ does not exist on that interval, but I don't know where to go from that statement.  Could anybody help me figure it out?  I have been staring at it for hours and I can't figure out where to go.  Thank you.


I'm coding a real-time graphics application in C++, so efficiency is very important. Now I always wondered how expensive is a function call itself? (for instance a function that has zero parameters)  I currently have this big function I wrote that can either be very long in code because I tried to avoid as many "helper function" calls as I could, or be much shorter and easier to read but includes many helper function calls.  I must note that this "big function" may be called hundreds and or even thousands of times per second.


Book about very long lived wizards who live in a secret grove and watch society evolve

I'm looking for the name of a book series I read when I was younger (maybe early 2000s?) that follows a family of very long-lived wizards/magicians who live in a tower in some sort of secret grove and watch human society evolve from a distance. There are multiple books, possibly each one following a different wizard/generation of wizards. I think one of the main characters is a woman who dresses in blue. I think the opinions of the common people towards magic change throughout the series, but definitely at some points they're feared/hated/persecuted and have to hide their identities when they go out into the world. One of the early novels might follow a human man/boy who meets a talking cat (possibly one of the wizards in disguise) which helps him unlock his magic powers. I think there's a scene where he's defending a castle and uses a spell to multiply his breath into a gale that blows away attackers. There's a scene about the trees in the forest around the wizards' grove. They dive into the tree's minds and see their slow-paced long-term view of the world. The wizards might worship, or even be servants of, some sort of god that lives in the grove with them. Near the end of the series they have a confrontation with an evil uncle who lives in a cave or something.


Lagrange Multipliers of distance from point to a function with respect to tangent and normal spaces.

I have a question with regards to lagrange multiplers. The question is as follows: Find the points on the sphere x^2+y^2+z^2=4 that are closest to and farthest from the point (3,1,-1). Now, it is clear to me that the distance from any point to (3,1,-1) is simply using the R^3 metric, d=$$\sqrt((x-3)^2+(y-1)^2+(z+1)^2$$ and I can make the algebra easier by considering $$d^2$$. However, my question is as follows: How can I be sure that the maximum or minimum occurs when  $$\nabla(d^2(x,y,z))=\lambda\nabla(g(x,y,z))$$ where $$g(x,y,z)=x^2+y^2+z^2$$? I would like an explanation in terms of tangent and normal spaces please? As i'm unable to find one.  Furthermore, it is to my knowledge that the lagrange multiplier works when the contours of the function f(x,y) just touches the constraint g(x,y)=c. However, is it possible to have contours of f(x,y) where the contours increase and decrease and wouldn't then the lagrange multiplier not work?


How should I manage constants in a Java project

Usually we manage constants in interfaces. e.g.:  public interface CommonConstant {     int A_TYPE1=0;     int A_TYPE2=1; }   But I'm thinking that if the constant belongs to a class, we may just put it into that class? e.g.:  public class A {     public enum Type {         TYPE_ONE(0),         TYPE_TWO(1);          public final int val;         Type(int val) {             this.val = val;         }     }      private int type;     ... }   So which way should be better?


Constraining predicted probabilities of a poisson regression with a binary outcome

I have used a modified poisson regression to model a binary outcome because I want to obtain relative risks, rather than odds ratios. The predicted probabilities are of interest, but many are beyond the range [0, 1].  Is there an appropriate way to constrain these to occur in the range [0, 1]? If a solution exists, I am keen to apply it to standard glm models and models generated using glmnet in R.


So there are a few posts about this already, but they skip over the problem I have.  The proof of Cantor's theorem elegantly shows that if we consider $f:A\rightarrow \mathcal{P}(A)$, the set $B=\{x\in A : x\not\in f(x) \}$ by its definition cannot lie in the image of $f$, precluding it from being a bijection - hence power sets have strictly greater cardinality.  But now, I thought one (obvious) way to characterise the "set of all sets" would be $S=\mathcal{P}(S)$, as indeed, it contains all possible sets (perhaps here is the problem, but I don't immediately see how using this as a definition for the set of all sets is bad). Now consider simply taking the identity function $i:S\rightarrow S$. Then $B=\{x\in S : x\not\in x \}$ - the set of all sets which do not contain themselves. But this doesn't exist. It's exactly the set of Russell's paradox. If this isn't a set, and so is not in $S$, then the proof no longer offers an obstruction to $i$ being surjective.    Each other post I've seen on the matter uses Cantor's theorem to show such a set doesn't exist. My query is to find that something else that must be happening, since I think the proof has issues for this particular set. I'm expecting other issues to arise with the definition $S=\mathcal{P}(S)$...


I'm running into a common pattern in the code that I'm writing, where I need to wait for all threads in a group to complete, with a timeout. The timeout is supposed to be the time required for all threads to complete, so simply doing thread.Join(timeout) for each thread won't work, since the possible timeout is then timeout * numThreads.  Right now I do something like the following:  var threadFinishEvents = new List<EventWaitHandle>();  foreach (DataObject data in dataList) {     // Create local variables for the thread delegate     var threadFinish = new EventWaitHandle(false, EventResetMode.ManualReset);     threadFinishEvents.Add(threadFinish);      var localData = (DataObject) data.Clone();     var thread = new Thread(         delegate()         {             DoThreadStuff(localData);             threadFinish.Set();         }     );     thread.Start(); }  Mutex.WaitAll(threadFinishEvents.ToArray(), timeout);   However, it seems like there should be a simpler idiom for this sort of thing.


How do I start developing a lens for Unity?

I would like to know how to create one of those lenses for unity. I know how to program. but I don't know where to start. Are there certain libraries I should use or docs that I should read? Are there wiki pages that I can reference?  My google-fu has so far failed me.


GTA V Online Character Transfer PS3 to PS4

I recently just bought a PS4 that I couldn't pass up (Price Wise) and decided to try and transfer my GTA V Online Character.  Stats: All stat bars full $204,000,000 Rank: 149  I've been playing the game since it came out, which was around 2013 I believe. I quit playing the game about 8 months ago because my hard drive in my PS3 died on me so I decided to put the console on the shelf for a while. Like stated above, I just bought me a new PS4 and was looking to try and transfer my character over. I tried calling Rockstar Support about my situation and all they told me was that they don't allow transfers anymore.   So here's my question... Is there absolutely any way that I can transfer my character to my next gen console?


Why does du report a size of 0 for some non-empty files on a HFS+ partition?

What is the explanation for the difference:  $ ls -l /Applications/Safari.app/Contents/Info.plist -rw-r--r--  1 root  wheel  15730 11 jui 15:02 /Applications/Safari.app/Contents/Info.plist  $ du -sh /Applications/Safari.app/Contents/Info.plist 0B     /Applications/Safari.app/Contents/Info.plist   Once the file is copied in my home folder, ls and du report the same number.  $ cp /Applications/Safari.app/Contents/Info.plist . $ du -sh Info.plist; ls -l Info.plist 16K Info.plist -rw-r--r--  1 ant  staff  15730 17 oct 16:53 Info.plist   Both directories are on this partition ( / )  diskutil  info / Device Identifier:        disk0s2 Device Node:              /dev/disk0s2 Part of Whole:            disk0 Device / Media Name:      ml2013  Volume Name:              OSX.10.8 Escaped with Unicode:     OSX.10.8  Mounted:                  Yes Mount Point:              / Escaped with Unicode:     /  File System Personality:  Journaled HFS+ Type (Bundle):            hfs Name (User Visible):      Mac OS Extended (Journaled) Journal:                  Journal size 40960 KB at offset 0xc83000 Owners:                   Enabled   Here is the output of stat:  $ stat  Info.plist 16777218 8780020 -rw-r--r-- 1 root wheel 0 15730 "Oct 17 17:47:12 2013" \  "Jun 11 15:02:17 2013" "Jun 11 15:02:17 2013" "Apr 27 11:49:34 2013"\  4096 0 0x20 Info.plist


Is it true that f is differentiable, and $\lim_{x\to\infty}f(x)=0,$ then $\lim_{x\to\infty} f'(x)=0$

Is it true that   If $f\in C^1(\mathbb{R})$ and $\lim_{x\to\infty}f(x)=0$, then $\lim_{x\to\infty} f'(x)=0$.


Lack of accuracy for my open market price forecasting

I'm trying to solve a problem to train my skill. I've daily data (each day during 10 years,2010 to 2020, except saturday and sunday).  I would like to predict like ten day after my data end.   Problem is my model are atrocious. I tried xgboost, svm and Prophet for now.   I think the problem is : I always worked on monthly data, and with monthly it's far easier to detect seasonality and so on. With daily data I'm kind of lost.  I thought : "Why not transform into monthly instead of daily ?" But how to predict only few days with monthly ? I don't think it's possible.   So if you have some tips to improve my work with daily data, I'll be very grateful. I'm quite new so any hel would be appreciated.  Thanks. :)


Select different country mirror than "locale"

Good day,  I'm installing Ubuntu instances in Germany or France datacenters, but with the locale/etc. set for South Africa. Now the (hyper intelligent) Ubuntu installer (contrary to the Debian installer) doesn't allow me to set the mirror/country to use for the package downloads, which makes the installations quite slow (other than setting up a mirror myself and point every installation to that one, but that would be cumbersome for various reasons)  SO, how do I tell the installer to let me pick the mirror I want to use contrary to my locale/country settings?


How to install Eclipse C/C++ in Ubuntu 18.04

To clean install Eclipse for C/C++ on Ubuntu 18.04 I tried sudo apt install eclipse eclipse-cdt. It's showing an error, see the log file....  log file..... !SESSION Fri Aug 16 14:39:20 IST 2019 ------------------------------------------ !ENTRY org.eclipse.equinox.launcher 4 0 2019-08-16 14:39:20.065 !MESSAGE Exception launching the Eclipse Platform: !STACK java.lang.ClassNotFoundException: org.eclipse.core.runtime.adaptor.EclipseStarter     at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471)     at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)     at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)     at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:626)     at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)     at org.eclipse.equinox.launcher.Main.run(Main.java:1438)     at org.eclipse.equinox.launcher.Main.main(Main.java:1414)


The problem is from Evans PDE 2.5 problem 18 How to solve the equations?  Assume u solves the initial-value problem  $u_{tt}-\Delta u=0$ in $R^n \times (0,\infty)$  $u=0$, $u_t=h$ on $R^n\times \{t=0\}$  Show that $v:=u_t$ solves  $v_{tt}-\Delta v=0$ in $R^n \times (0,\infty)$  $v=h$, $\ v_t=0$ on $R^n\times \{t=0\}$  (This is Stokes' rule)


Why are points deleted when the question is deleted?

Why are the reputation points one gets for an answer deleted if the question was deleted? I mean, you made the effort of answering the question with valuable information, spending time for it, and then, just because the question wasn't as good as the answers, you lose reputation.  Seems very unfair to me. (I just lost about 100 points on Stack Overflow.)


How to calculate no. of binary strings containg substring “00”?

I need to calculate no of possible substrings containing "00" as a substring. I know the length of the binary string.  Eg: for a string of length 4, possible substrings are: 0000 0001 0010 0011 0100 1000 1001 1100  I just need the number of possible combinations, not enumerate all of them.


Evaluate the determinant of a rank-1 matrix plus $I$

let $a_1, .......a_n \in \mathbb{R}$. Evaluate  the determinant   $\begin{bmatrix} 1+a_1 &a_2 &....&a_n\\a_1 & 1+a_2 &....&a_n \\...&...&....&...\\a_1 &a_2& ....&1 +a_n \end{bmatrix}$  First  i take $2\times2$ matrix A =$\begin{bmatrix} 1+a_1 &a_2 \\ a_1&1 +a_2 \end{bmatrix}$  As Determinant of $A = (1+a_1)(1+a_2) -a_1a_2= 1+a_2+a_1a_2 -a_1a_2= 1+ a_1 + a_2$  I don't  know  how  find the determinant  of $n\times n$ matrix.  Any hints/solution  thanks u


The scancode shown by dmesg is different from that from showkey

I'm using Debian Jessie with LXDE on a recent notepad. The command "showkey -s" prints "0xe0 0x4c 0xe0 0xcc" when Fn+F2 is pressed. But dmesg tells me:   atkbd serio0: Unknown key released (translated set 2, code 0xab on isa0060/serio0).     atkbd serio0: Use 'setkeycodes e02b <keycode>' to make it known.   Two questions: 1. Where the scancode e02b comes from? 2. Why the command setkeycodes e02b 44 works but not setkeycodes e04c 44?  I also noticed that when I press Fn+F2, "evtest" prints 'ab':      Event: time 1481025600.385595, type 4 (EV_MSC), code 4 (MSC_SCAN), value ab        Event: time 1481025600.385595, -------------- EV_SYN ------------value 1         Event: time 1481025600.394373, type 4 (EV_MSC), code 4 (MSC_SCAN), value ab         Event: time 1481025600.394373, -------------- EV_SYN ------------       The command          setkeycodes ab 44       works too. Can someone help me understanding what's wrong? Thank you all.  EDIT: Both Fn+F2 and Fn+F3 have the same scancode (0xab) for evtest and dmesg, but showkey prints two different scancodes:      0xe0 0x4c 0xe0 0xcc    for Fn+F2     0xe0 0x54 0xe0 0xd4    for Fn+F3   I wonder where the scancode 0xab printed by evtest comes from.


I am watching a discrete math video where the professor says that using the Pigeonhole principle is easier than using the first principles.  What exactly are the first principles and what in general does this statement mean?


I need help with proving this:     Prove that if $a \mid b$ and $b \mid c$, then $a \mid c$.   My initial start was as the following: \begin{align*} a \mid b = a*b\\ c \mid b = a*c \end{align*} so combining $a+c=[a*b]+[c*b]$, then I am lost.


I'm looking for a way to save a wepgage along with its gifs (). I know how to save a single gif, but my goal is to save the whole webpage (not as a pdf) and its gifs so that, when I open the file, I can see text and gifs. Thank you in advance.


I wonder when verbs like think or know are followed by that; I encountered both forms, is there a difference?  For example,      I know that he did it. // I know he did it.   Are the two sentences both correct?


Does exiling a creature after it has been destroyed or dealt lethal damage still count as if it "died"?

I'm actually working on an alternative card set. While designing tribal mechanics, I have encountered a problem with a single thing: does a creature exiled after being destroyed (instead of being put into graveyard) still counts as if it "died"?   So, let's imagine a situation:   deals damage to target 3/5 creature. Then, to finish the creature I cast ... so, instead of dying (being put into graveyard) the creature gets exiled.  If Sengir Vampire dealt damage to a creature finished with Pillar of Flame, will he get +1/+1?


How to include the symbol $ within a url?

I need to write a url including a character which seems a command , $  the entire command is :   \item URL - this is set as "\nolinkurl{http://localhost:9200/\$*/pcap/}";    but this produce:     URL - this is set as " \protect\T1\   textdollar*/pcap/ "   how can I avoid part "\protected\T1\textdollar" ?


Can we use quantum entanglement as a way to send information or data?

Can we use entangled particles to transmit information or data such as TCP/UDP packets?  If so why hasn't this been done yet? Surely the costs of bringing this to market are much cheaper than laying submarine cables?


I have a file that contains entries that are indexed by a key:  \newglossaryentry{[alpha key]} {     [some lines with arbitrary content] }   Two entries may be separated by one or more lines. How would I sort these entries based on their key? A subsidiary question is what regular expression for this pattern?   Thanks.


How do you summon chests with loot tables with command blocks in Minecraft v1.10.2?

I was using the command below to summon it and already had put the loot json in my Minecraft folder, but it would still only spawn empty chests.  /setblock ~ ~2 ~ minecraft:chest 1 0 {BlockEntityTag:{LootTable:"mctools:chests/NorthDungeon1"}}


Is back-shifting necessary in speech and writing

Can I say "I told you he is going to the book club" when he has already gone there by now; or is it necessary to back-shift it to past i.e. "I told you he was going to the book club".  So will I be understood perfectly if I used the "is going" version (not back=shifting it). This situation seems new to me. So I thought I'd ask that: Does it seem difficult to understand for the other person if we do not back-shift to past??. And is it gramaticaly correct??


Why can't I use \ifstrequal to check the \jobname?

I want to use the same source file to compile various target files using the -jobname option. I want to ensure that the option is not forgotten, so my approach was to check whether the \jobname is equal to the source file name. The check does not work as expected:  % save as file mwe.tex \documentclass{article} \usepackage{etoolbox}  \begin{document}   \typeout{=== JOB: {\jobname} ===}   \ifstrequal{\jobname}{mwe}{\errmessage{Please specify a different jobname.}}{}   Job \jobname \end{document}   If I compile this file with pdflatex -jobname foo mwe.tex, I get the following output:  This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013)  restricted \write18 enabled. entering extended mode (./mwe.tex LaTeX2e <2011/06/27> Babel <3.9h> and hyphenation patterns for 78 languages loaded. (/usr/local/texlive/2013/texmf-dist/tex/latex/base/article.cls Document Class: article 2007/10/19 v1.4h Standard LaTeX document class (/usr/local/texlive/2013/texmf-dist/tex/latex/base/size10.clo)) (/usr/local/texlive/2013/texmf-dist/tex/latex/etoolbox/etoolbox.sty (/usr/local/texlive/2013/texmf-dist/tex/latex/etex-pkg/etex.sty)) (./foo.aux) === JOB: {foo} === [1{/usr/local/texlive/2013/texmf-var/fonts/map/pdftex/updmap/pdftex.map}] (./foo.aux) )</usr/local/texlive/2013/texmf-dist/fonts/type1/public/amsfonts/cm /cmr10.pfb> Output written on foo.pdf (1 page, 10274 bytes). Transcript written on foo.log.   The problem is: If I compile it with pdflatex mwe.tex, it shows the job name mwe, but the expected error message does not appear:  This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013)  restricted \write18 enabled. entering extended mode (./mwe.tex LaTeX2e <2011/06/27> Babel <3.9h> and hyphenation patterns for 78 languages loaded. (/usr/local/texlive/2013/texmf-dist/tex/latex/base/article.cls Document Class: article 2007/10/19 v1.4h Standard LaTeX document class (/usr/local/texlive/2013/texmf-dist/tex/latex/base/size10.clo)) (/usr/local/texlive/2013/texmf-dist/tex/latex/etoolbox/etoolbox.sty (/usr/local/texlive/2013/texmf-dist/tex/latex/etex-pkg/etex.sty)) (./mwe.aux) === JOB: {mwe} === [1{/usr/local/texlive/2013/texmf-var/fonts/map/pdftex/updmap/pdftex.map}] (./mwe.aux) )</usr/local/texlive/2013/texmf-dist/fonts/type1/public/amsfonts/cm /cmr10.pfb> Output written on mwe.pdf (1 page, 11747 bytes). Transcript written on mwe.log.   I read about the catcode issue caused when using \jobname in combination with \ifthen -- however, according to the etoolbox documentation, \ifstrequal is catcode-agnostic. What else is going (wr)on(g) here?


Do I need a transit visa going through the US?

I am an Iranian citizen travelling from Canada to Iran. I'm holding a Canadian work permit.  Do I need a transit visa if my flight goes through the US?


Odds of rolling doubles or triples given N 6-sided dice

Over the holidays I played a dice game where each player had 3 to 7 d6 to roll each turn.  The game gave certain advantages to doubles and triples.  I wanted to know the odds of rolling doubles or triples given N dice to understand the importance of "upgrading" to more dice.  My question is really about how to reason about such problems:  It's easy to see that the odds of rolling doubles with 2 d6 are 1/6 (first die can be anything, and 1/6 of the time the second will match).  It's also easy to see that with 7 dice the odds are 1.0 (6 dice could be 1..6, but the 7th must match one of them).  The middle cases are fuzzier to me.  I ended up writing a program to enumerate all of the possibilities (even 6^7 is only 279,936 cases to evaluate) because that was the only way I felt I could verify any closed formula I came up with.  This also enabled me to distinguish cases of multiple doubles (or triples).  I would like to know how to derive closed forms and how to validate such solutions without brute-force simulation.


How do I find the windowid of Google Chrome to pass to screencapture -l

I'd like to use screencapture -l to do automated screen captures of Google Chrome. This requires knowing the windowid of the Google Chrome process that's running.  For apps that support Applescript,  has the answer. But that solution doesn't work for apps that aren't scriptable, like Google Chrome.  Is there any way to retrieve the windowid from a running Google Chrome process from a Python script? I know that the Quartz Debug app can do it, but that's a GUI app, so it can't be invoked via script.


Finding the inverse of $I+N$ where $N$ is nilpotent

Suppose that $N \in M_{n,n}(\mathbb{C})$ is nilpotent (that is, $N^k = 0$ for some integer $k > 0$). Show that $I+N$ is invertible, and find its inverse as a polynomial in $N$.  I think I got the first part down "intuitively". Noticing that $N$ is nilpotent, so $N$ will be a matrix with a diagonal (any diagonal) with just $1$'s as its entries. Then if I add the identity matrix to it, the diagonal will definitely have $1$ as a diagonal, and so $\det(N+I) = 1$ hence invertible. Is there a more standard way to prove this rather than just "talking" through it? Also, I'm unsure how I could approach the second part.