How many elements of order two can a nonabelian group have?

What is the largest proportion of elements of a nonabelian group that have order at most $2$?   In other words, given $G$ a nonabelian group with order $n$, and $k$ elements of order at most $2$, how large can $k/n$ be?  A colleague and I have been thinking about the following for a couple of days. Unfortunately neither of us knows much about a group theory beyond a first course (and in particular, no representation theory to speak of), so it may be simple, but beyond our expertise. We have made some progress:   An abelian group of order $n$ can have $n$ elements of order at most $2$, at least when $n=2^m$ for some integer $m$: $(\mathbb{Z}/2\mathbb{Z})^m$ works. Also, there is a priori no restriction on elements of prime order $p>3$ in nonabelian groups: a nonabelian group can have as many elements of order $p$ as we like: one of the two nonabelian groups of order $p^3$ has $p^3-1$ elements of order $p$, and this generalises to $p^m$ for $m>3$ by taking a direct product of this group with $(\mathbb{Z}/p\mathbb{Z})^{m-3}$. Now, as for the case we're actually interested in: elements of order $2$ in nonabelian groups.    A lower bound for the maximum of the ratio $k/n$ is $3/4$: examples with this ratio are $ D_8 \times (\mathbb{Z}/2\mathbb{Z})^m $. An upper bound for the maximum has been suggested by my colleague: suppose that $a,b$ are elements of order at most $2$. Then $$ ab = ba \iff aba = b \iff (ab)^2 = e, \tag{1} $$ i.e. $a$ commutes with $b$ if and only if $ab$ also has order at most $2$ (this immediately implies there must be an element of order larger than $2$, of course, or the group would be abelian). Now, the largest proportion of pairs that commute with one another is $5/8$ (i.e. there are at most $5n^2/8$ pairs that commute), by the $5/8$ theorem (, ). If the set of elements of order at most $2$ is $H$ (not necessarily a subgroup), then $\lvert H \rvert = k$. Let $h \in H$, then  $ hG = G $ by the group property. The most elements of $h' \in H$ for which the product $hh'$ can lie outside $H$ is $n-k$, so the number of $h'$s with $hh' \in H$ is at least $2k-n$, provided that $2k>n$ (the interesting case). There are $k$ $h$s, which is a total of at least $k(2k-n)$ pairs $hh'$s that lie in $H$. These pairs then all commute by $(1)$, so by the $5/8$ theorem, $$ k(2k-n) \leq \frac{5}{8} n^2 , $$ or $$ \left( \frac{k}{n}- \frac{1}{4} \right)^2 \leq \frac{3}{8} , $$ so $$ \frac{k}{n} \leq \frac{1}{4}(1+\sqrt{6}) < 0.863 . $$ One could do slightly better than this by treating the identity separately, worrying about elements with higher order that commute with their own powers, and so on, but none of this gives more than an $O(1/n)$ correction, as far as I can see.


How can I figure out which App has created certain folders/files?

I searched a lot but couldn't find any direct answer. There must be a way to figure out from which App a certain folder or file within /storage/emulated/0/ was created.


What is effect of increasing number of hidden layers in a Feed Forward NN?

Does increasing number of hidden layers improve accuracy or after adding some layers improvement won't happen? Does increasing number if hidden layers much more than the sufficient number of layers cause accuracy to decrease? Do we need more epoch to train network?


Multiple account user got pissed off at me and is down voting me, how do I act?

This is not a case of serial down voting.   This looks like a revenge kind of thing, at least it looks like that to me. What I am trying to do its to find out what can I do in this specific situation.   and  seem to be owned by the same user - :    I can't be 100% sure but it looks very suspicious.  I have received 2 down votes almost within the same time then about 20 minutes ago I have got another  - seconds after the question has been edited by mr S.  What can I do to prevent further down votes? I am aware of how the serial down voting system works but like I said this isn't the case specially that the user may have more than 2 accounts.   What does stackoverflow offer in terms of reporting suspicious down votes and multiple accounts users? I wouldn't want to stop contributing but if there is no way to report/stop such behavior from a pissed-off user then I am most likely going to reconsider the whole point of helping this community.


How do you interpret the instantaneous causality test?

I have used the causality function to test a VAR(3)-model for Granger causality. For one variable the following results were computed: The test found that H0 could not be rejected for the Granger causality test, but for the instant causality test with H0 = No instantaneous causality But how can I interpret this result now? What does instantaneous causality mean?


For primes $p,q$, what are the solutions to $x^2=(p+q)x\pmod{pq}$

For primes $p,q$, what are the solutions to $$x^2=(p+q)x\pmod{pq}$$


What is the Physical Meaning of Commutation of Two Operators?

I understand the mathematics of commutation relations and anti-commutation relations, but what does it physically mean for an observable (self-adjoint operator) to commute with another observable (self-adjoint operator) in quantum mechanics?   E.g. an operator $A$ with the Hamiltonian $H$?


What would a relativistic set of 'suvat' equations look like?

In newtonian dynamics  are relations between the initial and final speeds $u$ and $v$ of an object which covers a displacement $s$ during time $t$ under constant acceleration $a$, and they are essentially \begin{align} v &= u + at\\ s &= ut + \frac{1}{2}at^2, \end{align} and so on. Is there a corresponding set of equations for relativistic dynamics? I imagine that, for instance, the two equations above would have to factor in length contraction or time dilation, so is there a valid equivalent of 'suvat' equations?


How to Specialize member function of a templatized class?

I have a templatized class definition in test.hpp  /////////////////////////////////////////////// class point1 { public: int z0;  point1(): z0(1) {} }; /////////////////////////////////////////////// class point2 { public: int z1;  point2(): z1(2) {} }; ///////////////////////////////////////////////  template <class T> class line {  public: T p1;  void printPoint(void); };   and in implementation file test.cpp I am trying to specialize the printPoint function of class line   ///////////////////////////////////////////////  template<>  void line<point1>::printPoint(void)  { cout<<p1.z0<<endl;  }   template <class T>  void line<T>::printPoint(void)  { cout<<p1.z1<<endl;  }  //////////////////////////////////////   and main function is in testmain.cpp   int main()  { line<point1> r1; line<point2> r2;  r1.printPoint(); r2.printPoint();   int abc; cin>>abc; return 0;  }   But linker throwing error that printPoint function is multiply defined. Is it a correct way of member function specialization of a class if not than how to specialize member function of a templatized class? Please help.


I consider buying a Chinese tablet with an Exynos 5250 SoC. It is a Voyo A15. It is not supported by CyanogenMod, but there is a  available for this tablet. I would want to install Ubuntu Touch on it.  My question: Would it be possible to port Ubuntu Touch to this device? Considering it has the same SoC as the Nexus 10. I have enough Linux experience (of building kernels etc.), so I could do (at least try to do) the porting myself. The manufacturer has not yet released the source for their ROM, but the drivers for the Exynos chip are available. The Exynos is not the only chip on the tablet, so if the manufacturer doesn't release those drivers, is it still possible?  Maybe this is not the right place to ask this question, should I try at CyanogenMod forums? Maybe there is someone with experience of porting CyanogenMod/UbuntuTouch to exotic Android Tablets?


For what values of $ a $ is the set $A=\{(a^2,0,1),(0,a,2),(1,0,1)\}$ a basis of $\mathbb{R}^3$

For this I used the method of making the determinant nonzero. First I create the array \begin{equation} \begin{pmatrix} a^2 & 0 & 1\\ 0 & a & 2\\ 1 & 0 & 1 \end{pmatrix} \end{equation} Then $\det(A)=a^3-a=a(a^2-1)$ Where we can see that for the determinant to be different from zero $ a $ cannot take the values of $0,1,-1$. Therefore the values that $ a $ can take so that $ A $ is a base of $\mathbb{R} ^ 3 $ are $\mathbb{R}\backslash \{0,1, -1\}$. This is correct?


What is a good way to find the index of an element in a list in Python? Note that the list may not be sorted.  Is there a way to specify what comparison operator to use?


Will a Canon XL1s lens work with Canon EF mount cameras?

Would I be able to use a Canon XL1s lens on a Canon EF-mount camera, such as the 5D, without an adapter? I'm looking to purchase one for my camera but I'm not sure if it will work.


Generate insert SQL statements from a CSV file

I need to import a csv file into Firebird and I've spent a couple of hours trying out some tools and none fit my needs.  The main problem is that all the tools I've been trying like  and  expect that my CSV file contains all the information needed by my Table.  I need to write some custom SQL in the insert statement, for example, I have a CSV file with the city name, but as my database already has all the cities in another table (normalized), I need to write a subselect in the insert statement to lookup for the city and write its ID, also I have a stored procedure to cread GUIDS.  My insert statement would be something like this:  INSERT INTO PERSON (ID, NAME, CITY_ID) VALUES((SELECT NEW_GUID FROM CREATE_GUID), :NAME, (SELECT CITY_ID FROM CITY WHERE NAME = :CITY_NAME)   How can I approach this?


Hi All: I have the code below ( which was mostly given to me by someone on this list a while back ) and I can't figure out how the length of the each of the boxes is determined. I just want to change two things in the code which works quite nicely as is.  I want the length of the box to be five times as long as it currently is so basically becomes a rectangle.  I want the text in the box to be written at the right end of the rectangle.   Some people have given me nice solutions in another thread-question that I posed but I never explained that the boxes have to line up in a certain way with the horizontal axis so the solutions weren't really appropriate but that was my fault because of my lack of specificity. Thanks a lot. Oh, I'm thinking that the length of the box is somehow determined in the definition of squared node but I don't understand minimum width, minimum length and minimum size. I imagine that y=1.5cm is the height which is fine ? Thanks again. \begin{tikzpicture}[ squarednode/.style={draw=black, minimum size=9.9mm}, y=1.5cm ]  \newcommand{\absval}[1]{\ifnum#1<0 -\fi#1} \newcommand{\fullmin}[1]{\ifnum\absval{#1}<10 0\fi#1} \newcommand{\nextstep}[1]{\pgfmathparse{int(#1+0.5)}\pgfmathresult}  % horizontal axis \draw[->] (0,0) -- (11,0) node[anchor=north] {min};  % \foreach \x in {0,...,10}      { %help lines     \draw [help lines, color=gray!30, dashed] (\x,0) -- (\x,6); %ticks     \draw (\x,1pt) -- (\x,-3pt) node[anchor=north] {\fullmin{\x}};     }  % labels \foreach \y/\m/\mm in {5.5/00/05,4.5/01/06,3.5/02/07,2.5/03/08,1.5/04/09,0.5/05/10}     {     \draw (-1.5, \y) node{DERZZZ\textsubscript{(11:\m{}-11:\mm)}};               }          %boxes     \draw (0.5, 5.5) node[squarednode] {$X_{1}^{*}$};                     \draw (1.5, 4.5) node[squarednode] {$X_{2}^{*}$};     \draw (2.5, 3.5) node[squarednode] {$X_{3}^{*}$};             \draw (3.5, 2.5) node[squarednode] {$X_{4}^{*}$};             \draw (4.5, 1.5) node[squarednode] {$X_{5}^{*}$};             \draw (5.5, 0.5) node[squarednode,dashed] {$X_{6}^{*}$};                              \end{tikzpicture}


How to add click event to link in data received with $.get?

Using jQuery, I get HTML data with the $.get() function.  In callback function, when I put a breakpoint, the data variable is not empty and I see my link with the proper class (deleteLink), so I can select it.  $.get(path, function(data) {     $(data).find("a.deleteLink").click(function(event) {         event.preventDefault();         DeleteRow(event);     });     $("#tbody_id").append(data); });   Example of data received:
     Some data	     X
   I've tried to append() data after and before assigning the event listener to the link.  Having no JS error when I receive data, having the good element returned with $(data).find("a.deleteLink") function, having also the correct
 element returned by $("#tbody_id"), and no error when I click on link, why DeleteRow() is never called?


Minimal polynomials for a matrice in a given field and in its extension

For given matrices $X$ from the matrix ring $M_{n,n} (F)$, where $F$ is a field,  the minimal polynomial for $X$ in $F[x]$ is the polynomial $P$ of the lowest degree with the following properties:  (*)$P\in F[x]$, $P$ is nonzero, monic (that is  its leading coefficient is one), $P(X)=0$.  Let $L$ be a field such that $F\subset L$. Then also $X\in M_{n,n}(L)$.   My question is: are the minimal polynomials $P$, $Q$ of $X\in M_{n,n}(F)$ in $F[x]$ and in $L[x]$ the same?  Clearly, if $P$ satisfies (*) then also  $P\in L[x]$, $P$ is nonzero, monic, $P(X)=0$. Thus $deg(Q) \leq deg(P)$ (in fact, by the properties of minimal polynomial, $Q|P$).


If G be a non-trivial group with no non-trivial proper subgroup, show that G is a group of prime order.  Attempt:  Given $G\neq \{e\}$ and let $a\in G, a\neq e$. Then $H=<a>$ is a subgroup of G. Then by the hypothesis, $H= \{e\} ~or~ G$. But $H\neq <a>, ~as ~a\neq e$. So G is generated by $a$.  I can show also that G is finite (if G is infinite, considering group $<a^2>$).     Let if possible, $o(G)=n=composite=kl, ~k,l>1$ are intergers. As $G=<a>$, $o(a)=n$. As $<a^k>$ is a subgroup of G, $(a^k)^l=a^{kl}=a^n=e\implies o(a^k)=l<n$, i.e $<a^k>$ is a subgroup of order $<n$, but G cannot have a non-trivial subgroup. So $l=1 ~or~ l=n$. How to conclude the rest?   The problem is in the shaded portion only. Please correct it.


"He tells Reince and I" sounds wrong, doesn't it?

The following is quoted from The Washington Post of yesterday:  “If you think they’re going to give you your country back without a fight, you are sadly mistaken,” Bannon said in reference to the media and opposition forces. “Every day, it is going to be a fight.” He continued, “And that is what I’m proudest about Donald Trump. All the opportunities he had to waver off this, all the people who have come to him and said, ‘Oh, you’ve got to moderate’ — every day in the Oval Office, he tells Reince and I, ‘I committed this to the American people, I promised this when I ran, and I’m going to deliver on this.’ ”　  Towards the end of this quote, Bannon says, "he [Trump] tells Reince and I, ..." Is this grammatically acceptable? Shouldn't he say instead, "he tells Reince and me, ...?"


Lubuntu 16.04 gets stuck at shutdown (nmi watchdog bug soft lockup - cpu#1 stuck for 22s)

Occasionally my computer(Lubuntu 16.04 64 Bit) gets stuck at shutdown. It shows the message nmi watchdog bug soft lockup - cpu#1 stuck for 22s and never finishes shutdown.This message comes after the message Reached target shutdown.. What causes this error? How do I resolve this?


So I wanted to download some software, and it says I need to put in my password, but I didn't put a password on my account, so I didn't add a password and clicked authenticate, but it says that my authentication attempt was unsuccessful, what do I do? I can't download anything now... and i'm new to ubuntu as well...


C++: call overrided method in base class's constructor

Suppose I have a base class A and a derived class B. B's constructor calls the constructor of A, in which I call a function, say func to do some type-dependent thing. I mean, I have a do-nothing func for A and override this method in B.    My problem: In the very phase of construction of B, that is, in the constructor of A, what is the type of the object? While, I think it's A. But I'm not sure. If it is A, I'm always calling A's func right? Regardless of the type of the object I want to construct. In VS, in B's constructor, I see the type for "this" is "B". While I step into and in A's constructor, I see type for "this" "A".


Is it possible to add a driver to my kernel without flashing a new kernel?

Is it possible to load a driver as a kernel module into my Galaxy S10, Magisk rooted without having to build a new kernel and flash it?


Is it hard to transfer contacts from one iPhone to another iPhone?

I just bought a new iPhone 6s, and want to move all the contacts from the old one to the new one. Can iTunes or iCloud help me do this, or are there any other ways?


Loop audio file from the command line (gapless) or into new file

The only command line solution for gapless playback I found so far (working with ALSA and JACK) is moc (»music on console«). While I'm still searching for a simpler way I was wondering if it is possible to loop an audio file into a new file for a given number of times?  Something like:  loop-audio infile.flac --loop 32 outfile.flac   for repeating infile.flac 32 times into outfile.flac


Compute:$$\prod_{n=1}^{\infty}\left(1+\frac{1}{2^n}\right)$$   I and my friend came across this product. Is the product till infinity equal to $1$?  If no, what is the answer?


At the start of Harry Potter and the Philosopher's/Sorceror's Stone Voldemort's Killing Curse backfires      due to Lily's sacrifice protecting Harry from Voldemort.   leaving Harry with his scar      and a loose piece of Voldemort's soul   and Voldemort as a loose soul, self-described as "Less than a ghost".  Voldemort was not dead, but had no physical body (until he got better in book 4).  What happened to his body?  Did it disappear?  Or was it left in the rubble of the house, alongside the bodies of James and Lily?


I'm looking for a closed-form expression (in terms of $n$), that will give the sequence  $$ (s_n) = \left( \frac{3}{10}, \, \frac{3}{10} + \frac{33}{100}, \, \frac{3}{10} + \frac{33}{100} + \frac{333}{1000}, \dots \right). $$  Can anyone think of one? I made a related post to this question several minutes ago but I realized I was interpreting the sequence wrong.


I've got table with different actions from users, it looks like that  | User_ID       | Action        |  | ------------- |:-------------:| | 10            | View          |  | 8             | Connect       |  | 10            | View          |    | 12            | View          |    | 10            | View          |      And i want to count how many users made "View" action. So i made Query  Actions.where( action: "View" ).group(:User_ID).count  But it showed me   {10=>3, 12=>1}  So I added second ".count" at the end  Actions.where( action: "View" ).group(:User_ID).count.count  And now it's working properly  Is double count here only and proper way?


Why do I need to supply a password for `sudo`, when I've added my account to /etc/sudoers with NOPASSWD:ALL?

On Ubuntu 18.04 (x64), I've added my account myusr to /etc/sudoers as follows:  myusr ALL=(ALL:ALL) NOPASSWD:ALL   However, I still need to supply a password for using sudo after inactivity/reboot.


What does "K+M+B 2016" mean in when written on a church wall?

I was recently in Prague, and while visiting churches I saw several times the inscription "K+M+B 2016" (sometimes with a C instead of K) written in chalk on a wall or a door. I only saw this in (Christian) churches so I assume this has some religious meaning. What does it mean?


Consequence of maximum modulus principle

Let $f$ be continuous on the closed unit disc $\overline D=\{z\in \mathbb C~:~|z|\leq 1\}$ and analytic in the open unit disc $D=\{z\in \mathbb C~:~|z|<1\}$. Suppose that $|f(z)|\leq a$ on the set $\{z\in \mathbb C~:~|z|=1, Im(z)\geq0\}$ and $|f(z)|\leq b$ on the set $\{z\in \mathbb C~:~|z|=1, Im(z)\leq 0\}$. Then prove that $|f(0)|\leq \sqrt{ab}$.  How maximum modulus principle plays here to get an estimate for $|f(0)|$, Is there any role for $f(-z)$?


Reducing the size of the partition used by Windows

I want to increase the size allocated for Ubuntu, but for this I need to reduce the size for Windows. Gparted does not allow managing Windows partitions. What to do?


I know this may seem like a duplicate question but I'm sure IT'S NOT, as I have searched a lot for an answer and I couldn't find one. So everyone is saying that one person cannot bend 2 elements at once, but if anyone else noticed the guy with the third eye in "The Last Airbender" (Combustion Man) he is bending both Fire and Air, how is that possible?


I have two div tags as below

hi

i m on top

   I want to display the upper div first, followed by the lower div but I can not change the declaration order in HTML.  I am using the following css  #outer{     position:relative; } #upper{     position:absolute;     top:0; }   But the upper is overlapping with lower.  UPDATE  I tackled the situation in following way as it does not disturb the design

displayed in second line

       displayed in first line
       By using the above code i perfectly tackled my use case. Thanks for everyone for giving answers


Drupal out of the box comes with a page (which is the default homepage) that is assigned to the node path.  How do I avoid users reach it, and redirect them to the actual homepage of the site?


(Does World of Warcraft have servers for all expansions?) Can I play old WoTLK?

I would like to start playing World of Warcraft (again, after very, very.. long time...). I heard that Cataclysm expansion greatly changes game mechanics, like deleting many stats (some of them I liked very much) or possibility to get them on items.   I don't like this 'simplification'. I very liked the old system, so I would like to play World of Warcraft: Wrath of the Lich King (+ Burning Crusade ofc.), without further expansions (Cataclysm, Pandoria or newest one). But can I do this? Are there servers for all expansions, so people don't need to buy anything more, or I would need to have at least Cataclysm or some other expansion?  I would like to play WoTLK very much, without all these very deep mechanics changes and stats deletions (it's really not the same gameplay :-[ ), and I almost bought it, but I just heard that some of the patches to new expansions can affect the old ones.  But, I suppose, something so important like game mechanics shouldn't be affected, right? ...Or they do, and I cannot play normal WoW : Wrath of the Lich King?


halt, poweroff, shutdown, reboot don't require root?

For some reason, I can run halt, poweroff, shutdown, and reboot as a regular user without root. How can I fix this? Is it something to do with user groups, or is it a seting somewhere?


\times vs. \cdot vs. parentheses vs. nothing while writing fraction multiplications

Is there a convention around writing multiplication of fractions. Let us take two examples to be specific.  Example A: $ 2 \times \frac{1}{2} $  Here are some ways to write this example:   $ 2 \frac{1}{2} $ (does not seem like a good idea because this means $2.5$) $ 2 \times \frac{1}{2} $ $ 2 \cdot \frac{1}{2} $ $ (2) \left( \frac{1}{2} \right) $   Example B: $ \frac{1}{2} \times \frac{3}{4} $  Here are some ways to write this example:   $ \frac{1}{2} \frac{3}{4} $ $ \frac{1}{2} \times \frac{3}{4} $ $ \frac{1}{2} \cdot \frac{3}{4} $ $ \frac{1}{2} \left( \frac{3}{4} \right) $ $ \left( \frac{1}{2} \right) \left( \frac{3}{4} \right) $   Is there a preferred way of writing such multiplications in each case?


How to show there are irreducible polynomials of any degree over $\Bbb Z _p$?

How do I show there are irreducible polynomials of any degree in $\mathbb{Z}_p[x]$, with $p$ prime?  I tried counting the number of reducible polynomials of any degree but that turned out to be hard... Any help?


Let $X$ be a random variable with values in $\mathbb Z_{\geq0}$. Show that $E[X]=\sum_{k=0}^\infty P[X>k]$.   The question is taken from Introduction to Probability Models, 10th Ed. (Ross, pg. 91).  Attempt. Let $X=\sum_{k=1}^\infty X_k$, with  \begin{equation}X_k=\begin{cases}1 & \text{when }X\leq k \\ 0 & \text{when }X>k\end{cases}\end{equation}  Since $E[X_k]=P[X\leq k]$,  $$E[X]=\sum_{k=1}^\infty E[X_k]=\sum_{k=1}^\infty P[X\leq k]=\sum_{k=1}^\infty \left(1-P[X>k]\right)$$  And at this point I'm at a loss as to how I should obtain the result.  Attempt 2. Following drhab's help, I reformulated the definition of $X$ in terms of $X_k$. Using the same $X_k$ (for brevity of this post), let $X=\sum_{k=0}^\infty(1-X_k)$. Then  $$E[X]=\sum_{k=0}^\infty E[1-X_k]=\sum_{k=0}^\infty(E[1]-E[X_k])=\sum_{k=0}^\infty(1-P[X\leq k])=\sum_{k=0}^\infty P[X>k]$$  I believe this is correct now.


key broke and stuck in U-lock with bike locked

Luck would have it my key broke off when I was trying to unlock my bike. The lock is U shaped ABUS. I've read people had this before, however biggest problem is that bike is now stuck at the school, locked to a metal grid. Half of the key is inside the lock and there is no way to pull it out. Obviously I can't take it to locksmith and my moves are pretty limited due to position it's locked in. I don't care about the lock. I wish to free my bike without losing the front wheel. Any suggestions?  Edit: Issue solved, by smashing lock few times to dislodge it since key broke very close to open position.


I have to run a command (mounting Windows file system. Machine is a dual boot system). If Ubuntu is already installed, I can go to /etc and edit rc.local and put my mounting commands there. So the next my Ubuntu starts, it will execute those commands and mount the Windows file. But my problem is, right now Ubuntu is not installed. I want to run the commands automatically when the Ubuntu gets installed the very first time.


What are the benefits of having local disks on hypervisor nodes running VMs off a SAN?

When an hypervisor like XenServer or vSphere can be run on diskless nodes (eg. by booting from flash cards or from the network) and VM storage is handled via a SAN, is there any good use for local disks?  Would it be better to have those disks even if not used to boot the hypervisor or to hold VMs? What are the reasons, if any, to choose completely diskless servers VS having some local storage?


Static int data value printing as hex instead of int [Java]

I have a code that is supposed to create an object assign it an Object ID from a static int value and then increment the static value. as shown below;  public class ObjB implements Serializable{  private static int ObjNum = 00000100;   String OID;  public static Booking newObjBTerminal() {         Booking O = new ObjB();     String O_ID = "N" + String.valueOf(ObjB.ObjNum);     System.out.println("Object ID is: " + O_ID);     Booking.BkNum++;        O.OID = O_ID;      }  }   I am expecting an output of  Object ID is: N00000100  Instead I get  Object ID is: N64  Any idea on whats going wrong?


Some of the packages of CTAN are really good but not discovered by many. I recently encountered one of the good ones, namely latexindent, and I thought that would be great if everyone introduces the best he/she is aware of. So,   Kindly please introduce what you found useful in CTAN that should be recommended to others.


Can't play DVDs through either VLC, Videos, or Kaffeine

Running this through an external DVD drive. Videos app says DVD source is required to play the file, but is not installed. Hitting play in VLC activates the disc (you can hear it start up in the drive) but nothing happens. I've installed Ubuntu Restricted Extras and libdvdread4 and libdvdcss.  I know varieties of this question have been asked before, but none of the answers I've tracked down are solving the issue.


MacBook Pro 2017 daisy-chaining with DisplayPort

I have a 2017 13" MacBook Pro (with two USB-C ports) with Mojave and wish to use it to daisy-chain a display to two external monitors through DisplayPort.  Unfortunately, it seems that although the hardware supports this, MacOS itself does not support multi-stream transport - the two monitors in the chain are mirroring their display with no option to extend instead.  Is there any third party driver or other software available to make this work as intended in MacOS? If not, what would be the best alternate solution to get it working? Ideally, I'd like to avoid buying a separate £200 dock to be able to use multiple monitors and still power the MacBook as well.  The monitors in question are Dell U2515h if that helps - they support daisy chaining through DisplayPort 1.2, although ideally, I'd also like to be able to chain to another monitor too.


Are there naming conventions for variables in shell scripts?

Most languages have naming conventions for variables, the most common style I see in shell scripts is MY_VARIABLE=foo.  Is this the convention or is it only for global variables?  What about variables local to the script?


How do I transfer email address from old Stack Exchange account to new account?

I have an old Stack Overflow account with a registered email address. However, this account is old and I don't want to use it anymore. I want to create a brand new account. BUT, I registered my big important email address with the old account and want to use this address for the new one!! But I receive the error, "this email address is already registered with an account".  Is it possible for me to unregister my email address from the old account and re-register with the new one. Preferably, not deleting the old account. As I will still be referring to it on occasion.


How can I keep a folder synchronized to an external USB hard drive?

I have a growing music collection which I manually keep in sync with an external USB drive. Sometimes I edit their ID3 tags, add or delete a file in either the hard drive or the USB drive, and I would like to keep those changes synchronized between both.  Does Ubuntu has something available that would help me with this scenario? Preferably something easy to use with a UI.  Update: To clarify my question, changes may happen on both the local hard drive or the USB drive, so the sync process must be on both directions.


Initial Segments and Initial Sections of Posets

For a set A with a partially ordering <=, define the following  1)  A subset s(x) of A = {y in A such that y <=x}  2)  A subset S of A with the property that for every x in S then all y in A which are <= x are also in S.  Most references I find call s(x) the initial segment of the element x in A. But in Azriel Levy’s book     he calls s(x) the initial section of x in A and defines S as an initial segment. I can’t find any other reference to a set defined as S is.   Levy goes on to say that every set s(x) has the property of S (which would appear to follow by transitivity).   To me it would appear that even if the ordering is total then it doesn’t necessarily follow that every S has an x where S = s(x): e.g. A is the rationals with normal ordering and S = {rationals that when squared <= 2} .  I chanced on the “initial section” reference reading a proof of transfinite recursion, p.27  of   Can anyone clarify segments and sections, confirm common usage of terminology, and give a hint or reference to the usage of sets like S ?


How to properly alert my data on button click via jquery and php

I used the code below to display json data from backend and it works fine as I can get all users id and email.

                              Email	                              Delete

                 Here is my problem. I want to delete content of result when Delete button is clicked and to this effect,  I have attached a Delete button  and pass users id and email in a form input but when I click on delete button for each result, the jquery cannot alert id and email so that i can further post it to ajax as per code below  It seems jquery is not responding delete action button. Please how do I alert users id and email first so that I can pass it to ajax. Thanks  $(document).ready(function(){  $('#del_btn').click(function(){ var id = $('#id').val(); var email = $('#email').val();  alert(id); alert(email);  // send ajax to delete email    }); });


Show that $\mathrm{S}_{m} \times \mathbb{N}^{m} \rightarrow \mathbb{N}^{m}$ defines an action of $\mathrm{S}_{m}$ on $\mathbb{N}^{m}$

This is an exercise from textbook Analysis I by Amann/Escher.  Let $G$ be a group and $X$ a nonempty set. Then $G$ acts (from the left) on $X$ if there is a function $$G \times X \rightarrow X, \quad(g, x) \mapsto g \cdot x$$ such that: GA1: $e \cdot x=x$ for all $x \in X$. GA2: $g \cdot(h \cdot x)=(g h) \cdot x$ for all $g, h \in G$ and $x \in X$. Let $\mathrm{S}_{m}$ be the set of all permutations of $\{1,2,\cdots,m\}$. Then $(\mathrm{S}_{m},\circ)$ is a group where $\circ$ is function composition operation. Show that $$\mathrm{S}_{m} \times \mathbb{N}^{m} \rightarrow \mathbb{N}^{m}, \quad(\sigma, \alpha) \mapsto \sigma \cdot \alpha := \left(\alpha_{\sigma(1)}, \ldots, \alpha_{\sigma(m)}\right)$$ defines an action of $\mathrm{S}_{m}$ on $\mathbb{N}^{m}$.  I am stuck at proving the GA2, i.e. $\pi \cdot (\sigma \cdot \alpha) = (\pi \circ \sigma) \cdot \alpha$.  My attempt: Clearly, $\operatorname{id}$ is the identity element of $\mathrm{S}_{m}$ and $\sigma \cdot \alpha = \alpha \circ \sigma$. Because $\operatorname{id} \cdot \alpha = \left(\alpha_{\operatorname{id}(1)}, \ldots, \alpha_{\operatorname{id}(m)}\right) = \left(\alpha_1,\cdots,\alpha_m\right) = \alpha$, GA1 follows. For $\pi,\sigma \in \mathrm{S}_{m}$ and $\alpha \in \mathbb{N}^{m}$, we have $$\pi \cdot (\sigma \cdot \alpha) = (\alpha \circ \sigma) \circ \pi = \alpha \circ (\sigma \circ \pi) = (\sigma \circ \pi) \cdot \alpha$$  It is clear that $\sigma \circ \pi = \pi \circ \sigma$ if and only if $(\mathrm{S}_{m},\circ)$ is Abelian, which is not true in general. Please help me figure out where I am wrong!


How do i extrude without faces intersecting (inside a cube)

I want to make that part of my mesh thicker, and the way i do it (extruding part by part) ends up with the two parts intersecting and i think it'll be a problem in the future.    here the problem


Can adjectives always be used as nouns when they denote a plural and are preceded by the definite article?

An adjective appears to be used as a noun when denoting an animate plural and preceded by the definite article:     'The successful are those who strive.'      'The foolish are those who procrastinate.'   Is this always the case?


I can't install TP-LINK TL-WN821N v5 driver on kali kernel 4.9.0

Inform  uname -r   Kali Rolling 64-bits  4.9.0-kali3-amd64   I have troubles at the make step while installing the driver  make ARCH=x86_64 CROSS_COMPILE= -C /lib/modules/4.9.0-kali3-amd64/build M=/root/rtl8192eu-linux-driver  modules make[1]: *** /lib/modules/4.9.0-kali3-amd64/build: No such file or directory.  Stop. make: *** [modules] Error 2   On the official website of TP-LINK, they said this device don't support in kernel v4.9.0. So I need your helps to fix this problem. Thank you.


How to change stroke width of line in Photoshop CS6?

I have drawn some lines with the line tool in Photoshop CS6.  The lines are vectors on a shape layer.  If I select the line with path selection tool I can change the stroke colour, in the options panel at the top, but not the stroke width (if I change the stroke width nothing happens).  Is there a way to change the stroke width?


Could bounty requests preserve paragraph spacing?

I posted a bounty at  , and in the process broke up what I had to say into three or so separate paragraphs, intended both to distinguish my major points, and give some whitespace instead of a wall of text.  The text of my request is visible at  , but it's a wall of text. Perhaps some people will be sufficiently motivated by a bounty to parse through what my multiple points are, but I regard the undistinguished block as less readable than the whitespace-endowed message I tried to set out clearly to any parties interested in the bounty.  Could bounty requests preserve paragraph delineation the way normal posts do?


How to compare multiple words separated by comma in an if statement?

I have a variable named title which is having the value "Javascript,XML,XHTML,CSS,Ajax". I need to compare in an if statement if the title equals to the above value some code needs to be run.  I have used   if (title == "Javascript,XML,XHTML,CSS,Ajax"){  } else if (title == " ") {  } else {  }   When the title is null, the code goes to the second else part and gets the correct result. But when the title is equal to Javascript,XML,XHTML,CSS,Ajax the code goes to the last else part instead of going to the if part.  What mistake have I done here? I have checked the upper lower case and also spelling along with the delimiter comma the string is same just as in the variable title. Then why do I not get the correct answer.


Black reflections at extreme angles with glossy shader on smooth surfaces

How do I remove them?    They don't appear when using flat shading.    Nothing in the scene can cause this.


Is there a word for implying something that is actually false to be true, without specifically stating it to be true or false?  As an example (can’t really think of anything better):     persons A and B on the phone:      (A) Are you ready, I’m near your house.         (B) (While still in bed) What do  you think, I’ll see you in 10.         (A) Alright, Just checking, I’ll see  you in 10 then.         (B) (Frantically tries to get ready).   Edit: I’m gonna anwser my own question here in case someone finds this post, but I think the anwser I was looking for is:  equivocate; “use ambiguous language so as to conceal the truth or avoid committing oneself.”


Read DateTime value in correct format with JQuery (passed from controller to ajax)

/Date(1482048633480)/ is the result when appending() the DateTime value into HTML.   $("#Date").append($('<div> '+ data.DateTimeFromController+' </div>'))   How to read data.DateTimeFromController in MM/DD/YYYY Hour/Min/Sec AM/PM format?


Does anyone know of a simple Image Editor, with functionality comparable to ,  for Ubuntu?  I've always found GIMP to be overkill and too complicated for what I want to do.


What would happen in a collision of an antimatter singularty and a matter singularity?

Would energy be released if a black hole made out of antimatter and another of matter were to collide?


getting syntax error while altering column in sql

Trying to add UNIQUE attribute to existing column, getting syntax error smartbrain=# ALTER TABLE users ALTER COLUMN email VARCHAR(100) UNIQUE NOT NULL;  ERROR:  syntax error at or near "VARCHAR" LINE 1: ALTER TABLE users ALTER COLUMN email VARCHAR(100) UNIQUE NOT...


Movie about afterlife, large towers with clothing and food

I saw this movie (or maybe it was a TV show) a long time ago.   All I remember is a larger number of people waking up in water and making it to the shore, I want to say they died and are waking up in an afterlife, but again the details are hazy. I remember there were these large towers near the shore the people got food and clothing from.   I was young, so I'm thinking it came out before 2004.  That's live action, not animated.


When and why do we take into account the curvature of the curve at infinitesimal scale in calculus?

Background  We know that the integral $\int f(x)~dx$ represents the area under the curve, where the area is represented by the sum of individual areas of elemental strips of the width $dx$ and height $f(x)$. As $dx$ is infinitesimal, we can ignore the error due to the curvature of the curve, and treat the elemental strips as almost 1-dimensional. As the curvature disappears at infinitesimal scale, the area becomes that of a perfect rectangle, $dx \times f(x)$.    Similarly, this can be extended to working out the volume of revolution, which consists of elemental "disks" of the face area $\pi f^2(x)$ and length $dx$. The name "disk" used in textbooks is really a cylinder with a large face area relative to a small (really, infinitesimal) length. The volume of a cyliner is equal to a face area $\times$ length, so the volume of revolution is $\int \pi f^2(x)~dx$. Again, this ignores the curvature of the original curve $f(x)$ and assumes that at each $dx$ the elemental unit is perfectly cylindrical.  The above are uncontroversial established textbook results.  Question  Why can't we extend the same principles in deriving the surface of revolution? If we take the cylinder as the elemental shape, the surface of revolution of the whole curve could be represented by the sum of lateral surfaces of the elemental cylinders, each equal to $2\pi f(x)\times dx$. So the whole surface would be equal to $\int 2\pi f(x)~dx$. But apparently this is wrong.  Instead, here, the textbook derivations () do take account of the curvature in $f(x)$, and use the elemental surface area equal to $2\pi f(x) \times ds$, where $ds$ is the curved length of the curve in each interval of $dx$. Hence, the elemental shape assumed is that of a tube, instead of a cylinder.  Why is it not acceptable to ignore the curvature here, but is acceptable in the calculations of area under the curve and volume of revolution?


JQuery Click() not firing on items added by laravel blade for loop

I have a dropdown menu where the menu items are filled dynamically from the DB using laravel blade template language. I'm trying to fire on click events on the menu items by JQuery click() by a class selector function but nothing is happening. Here's the menu:
     @foreach ($categories as $cat)
         id }}">             {{ $cat->name }}
     @endforeach

  An here's the JS in the base template where the menu is being included using @include()   Could someone catch what I'm doing wrong?


Are name based virtual hosts for non-web servers?

Does  only apply to web server? Or also to other servers which are  not web servers?  I ask this because in web servers, named based virtual hosts are implemented by HTTP Host header. I don't see virtual hosts for non-web servers.  Thanks.


Remote Desktop Client which allows to use some displays fullscreen

I am looking for a remote desktop client which allows to use two displays in fullscreen as remote, and use one display to run local apps.    So far I have tried   Remote Desktop Connection (windows builtin)   This tool does not allow to specify the number of monitors you want to use. It only allows to use one screen, or all screens. Resizing the display is not possible.   Windows 10 remote desktop app   This tool allows resizing, so it is possible to use two displays as remote, and one local. These two are however not used in fullscreen, resulting in weird resizing and fuzzy images.   Remote Desktop Manager Free   Same issues as Windows 10 remote desktop app, no fullscreen for the specified monitors.  So the question is: does someone know an application which checks all these boxes?   Can be used in Windows 10 Small or no license cost Allows to run some but not all displays in fullscreen mode


Limits: $\lim_{n\rightarrow\infty}\frac{nx}{1+n^2x^2}$ on $I=[0,1]$

I'm doing an assignment for my analysis course on the uniform convergence. And I have to assess the uniform convergence of the sequence $$f_n(x)=\frac{nx}{1+n^2x^2}$$ on the intervals $I=[1,2]$ and $I=[0,1]$. Before assessing whether there is uniform convergence, we need to provide the pointwise limit of the sequences. Now, for the first interval everything is okay, but I'm running into issues with finding the pointwise limit for the second interval.  It's clear to me that for $0<x\leqslant1$ the limit of the sequence should be zero. But when $x=0$ I'm not sure if this is also the case. Clearly filling in $x=0$ for any finite $n$ would give zero for $f_n(0)=0$, but how can we be sure this is still the case when $n\rightarrow\infty$?  Also, for the uniform convergence part of the assignment, I've gotten as far as seeing that I should use the fact that $f_n(\frac{1}{n})=\frac{1}{2}$, but I'm not really sure yet how to use this.  Any help is much appreciated!


Upgraded from 13.10 to 14.04. All seemed to go ok, but following reboot I get this message:     Serious errors were found while checking the disk drive for /.   If I ignore that one, I get a further message:     The disk drive for /tmp is not ready yet or not present   And fails to boot. What can I do? Is it possible to do a manual recovery?


The first sentence is passive and second is simple past but how can we tell that surprised is participle in first sentence and adjective in second one?.  1.I was surprised by how well the students did in the test.  2.The lady was surprised at what happened to her pet.


Finding $\lim_{n \to \infty}\sum_{k=n}^{2n}\frac{1}{k}$

Let $a_n$ be defined via $a_n = \sum_{k=n}^{2n}\frac{1}{k}$. Compute, $\lim_{n\to\infty}a_n$.   I have an handwavy argument that since $\lim_{n\to\infty}\left(\sum_{k=1}^n \frac{1}{k} - \log(n) \right) = \gamma$, where $\gamma$ is the Euler-Mascheroni constant, I think that the limit above is $\log(2)$, but I am a bit confused. Can someone help me with this? Thanks!


A surjective endomorphism (of a Noetherian ring) is injective.

The problem is stated as follows:  "Let $R$ be a Noetherian ring and $\theta$ be a ring homomorphism from $R$ to $R$. Show that if $\theta$ is surjective then it is also injective."  Regardless of the right solution, I don't understand why is the following wrong:     We have $\theta: R\to R$. By the isomorphism theorem $R/\ker\theta\cong\operatorname{Im}\theta$. Since $\operatorname{Im}\theta = R$, it follows $\ker\theta =0$, so it's injective.   Harsh criticism will be appreciated. Thanks.


From a recently reignited [casual] curiosity into particle physics thanks to the Fermilab YouTube channel, I read about the , followed by muons, naturally. Muons, it turns out have short lives, and they decay into an electron (and antineutrino), for example. Reading on how muons are created, I learned about the role of the cosmic rays, and intuitively I understand how 3 quarks can end up as 3 quarks and a quark–antiquark pion. [Charged] pions decay to muons, so my curiosity was satisfied, but only momentarily . . .  Until I realized this muon creation and the subsequent electron originated from quarks.  Q: How are quarks elementary when they can become leptons?  I'm either misunderstanding the meaning of a particle being elementary, or I'm missing something. (I can't get my head around that point; I also casually understand that the weak interaction is involved.)  Does it work the opposite way as well (lepton → quark)? Or, given enough time, will all elementary particles eventually decay to leptons? (Thinking out loud; not necessarily extra questions.)    I could not find the answer to my question on Wikipedia or via Google. I checked the related topics, for example,  But it's a different question about what makes up quarks/leptons (I'm content with the fact they're as small as they get according to the Standard Model).  Thanks to @AccidentalFourierTransform for the following links (and their links):       As far as I can see those posts do not address the quark → lepton decay. All the examples given are quark → another quark (or lepton → another lepton), which I have no issue with (the muon → electron example I gave). The same for the decays of virtual/mediating particles, e.g., photons and Higgs bosons. My issue is (was) the class-changing decay of the non-virtual particles.


Output voltage calculation for full wave bridge rectifier

What would be the calculation for the output voltage of this full wave bridge rectifier?    Thank you.


Are there any packages for project management charting - PERT charts, Gantt charts etc. I have seen flow chart packages, but not the others. Help will be appreciated.


Trying to do over 1000000 damage in a sword but a comma is in the way

/give @p diamond_sword 1 0 {AttributeModifiers:[{AttributeName:"generic.attackDamage",Name:"generic.attackDamage",Amount:100000000,Operation:2,UUIDLeast:669718,UUIDMost:872863}],HideFlags:0}   That command is giving the output of:  Syntax error: Unexpected "," at "unt:100000000>>,<<Operation:"   What is going on?  Bedrock Edition


Once in a while I get this bizarre behavior on my iPhone 5's screen with iOS 8.3.1. (The button says 'Approve' - in Hebrew).  I can't say if its SMS/MMS or something else. But it feels like Malware.   Anyone familiar with this behavior or something similar? What should I do next?


A rational number is one that can be written as $a/b$ where $a$ and $b$ are integers, $b\gt0$ ($a$ can take care of negative rationals), and I suppose $\gcd(a,b) = 1$.  Given some $n\in\mathbb{Q}$ where $n=a/b$, what is the next rational number?  At first, I naively thought that it was $(a+1)/b$ but of course that is absurd. Consider $n=1/2$. The next rational number is obviously not $1$.  I decided that one must make the "granularity" finer. For instance $n=1/2=2/4$, so by the above idea, the next one is $3/4$, which is better.  Extending that, is it correct that the next rational number is:  $$ \frac{1+\prod_{n\in\mathbb{Z^+},n\neq b}n}{\prod_{n\in\mathbb{Z^+}}n} $$  (We can factor in the sign of $a$ if we wanted to make this more correct)


I cant center image without absolute position and other esle

I have two div that each of them has an image and a caption.  I want image center vertically or fill div element without stretching or Any unusual resizing.  I searched and use any suggestion Like -  and answers of some questions in stackoverflow, but none worked.  I want use and display this elements responsive  I use this pictures for test:       .border_slide {   overflow: hidden; } .other_titles {   margin-top: 5px;   height: 120px; } .other_titles div {   width:49.5%;   margin-bottom: 5px;  } .other_titles_cap {   position: absolute;   z-index: 100;   width:100%;   background-color: rgba(69,69,69,0.4);   height: 70px;   margin-top: 80px;   transition: all 0.3s ease 0s; } /*.other_titles_cap:hover {   margin-top: 0;   height: 150px; }*/ .title2 {   height: 150px;   background-color: #9bfff0;   /*margin-left: 15px;*/   float: right; } .title2 img {   margin-top: 0;   transition: all 0.4s ease 0s; } .title2:hover .other_titles_cap {   margin-top: 0;   height: 150px; } .title2:hover img {   width: 115% !important;   opacity: 0.8;   transform:translate(7%,-10%);   -ms-transform:translate(7%,-10%); }  .title3 {   height: 150px;   background-color: #ffd5c4;   float: left; } .title3 img {   /* transform: translate(7%,-10%); */   -ms-transform:translate(7%,-10%);   margin-top: 0;   transition: all 0.4s ease 0s; }  .title3:hover .other_titles_cap {   margin-top: 0;   height: 150px;  } .title3:hover img {   width: 115% !important;   opacity: 0.8;   transform:translate(7%,-10%);   -ms-transform:translate(7%,-10%); }

title of Post2

title of Post3

     I Mostly need this for responsive mode in width size below 520px.  You can test this here:


There is a bluetooth audio delay on my Mid 2014 Mac on Mojave

Whenever I connect my bluetooth earbuds to my Mac, there is a noticeable audio lag when watching videos. How do I solve this. I use my earbuds with my Android phone and they work perfectly.


Ok, I just bought a brand new original iPad. Sounds impossible, right? Well, we just opened the box, and it is not even charging. There is no indication that this iPad even works even though it is technically "new." Is this something that Apple will need to fix or do I just need to let it sit on the charger overnight and hope it wakes up from a 2 year sleep in its box?


What's the meaning of asterisk underscore args as a Python parameter?

In this line  def onFaceDetected(self, *_args):   from  tutorial, what is the meaning of *_args as a parameter to a Python module's method?  I've seen lots of explanations for just an asterisk or just an underscore, but not both.


Count the number of words on each beamer slide?

Is there a way to automatically count the number of words on each beamer slide, and to display it on the slide? I would like this feature to be available only when I am creating draft versions of the slides. Ideally, I should be able to toggle this feature off when I create the final version of the slides for distribution.  MWE  \documentclass{beamer}  \begin{document}  \begin{frame}{First Slide} This is my first slide.  % I want to generate the word count below automatically nwords = 7 \end{frame}  \begin{frame}{Second Slide} This is my second slide. It has more words than the first slide.  % I want to generate the word count below automatically nwords = 15 \end{frame}  \end{document}   The reason why I ask this question is because some people recommend that a slide should not have too many words. For example, an article by Presentation Magazine titled  gives the rule of thumb of "less than 40 words per slide." It would thus be useful to know how many words I have in each slide.


Substituting string in a file by another string with leading zeros in linux

I have a text file filename for which I want to substitute a certain numerical string in row row_numby another one that starts with leading zeros. That row is:  "uuid": "34ba55d4-42fd-448e-862a-f1515"   And I would like to substitute the last four digits so that the desired end result is:  "uuid": "34ba55d4-42fd-448e-862a-f0155"   The command I am using is:  gawk  'NR=='$row_num'{gsub(/'1515'/,'0155')};1' filename > tmp && mv tmp filename   The problem is that linux interprets 0155 as an octal number due to the leading zero and returns:  "uuid": "34ba55d4-42fd-448e-862a-f109"   Resolving the interpretation by adding 10# to 0155 does not resolve my issue because then it is evaluated and the zero is avoided, yielding:  "uuid": "34ba55d4-42fd-448e-862a-f155"   How can I make the substitution so that I obtain the desired output?   I would like the solution to be general so that it also works in the case where the first element is nonzero, for which my provided solution does work.


crawling issue in my website about two week

I almost did this change before 20-21 days but still Google is not crawling Site.


Is there a hard upper bound to the deBroglie wavelength of a particle with vanishing momentum?

This is probably a stupid and simple question, but does the heisenberg uncertainty principle set this upper bound? That knowledge of the momentum is limited, so it can't reach a very low value and thus have a very large (visible) debroglie wavelength? I am figuring if you wanted to test this on a macroscopic particle you would need it frozen to near-absolute zero, but I assume QM comes in and makes it impossible to see visible wavelengths with the naked eye. Thanks!


Doctor Who: An Outrageous Amount of Running

As Donna notes in The Doctor's Daughter:     He saves planets, rescues civilizations, defeats terrible creatures, and runs a lot. Seriously, there's an outrageous amount of running involved ..."   I've been an huge Doctor Who fan since the relaunch in 2005 and I've often heard it mentioned that there's a lot of running in newer episodes (, , many more).  However, I've seen only a couple of the older episodes (a couple of Tom Baker episodes a long time ago and the Paul McGann movie in the 90s).  I'm just curious: can someone who was a avid watcher of the older episodes (pre-2005) tell me, has a lot of running always been a recognized characteristic of Doctor Who episodes or has it become more prevalent in episodes since the 2005 relaunch, perhaps because of the recent writers or the recent actors that have been playing the Doctor?


What is a simple way to write GUI apps with clojure?

I haven't seen any nice app frameworks for clojure yet. Are there any good sdks with binding for clojure or clojure script?


My computer stops working after I choose install ubuntu 13.04

I can boot Ubuntu easily and choose options but when I select install inside windows 8 and press continue , a black screen appears and Ubuntu CD comes out and if I press a button, the computer restarts. I have windows 8 acer laptop.


I want to find the number of elements of $GL(n,\mathbb{Z_p})$, $p$ prime. For $p=2$ I got 6 elements since one of diagonals has to be $0$ and the other $1$. But how should I deal with an arbitrary $n$ ? The expression for the determinant gets complicated.


I am having trouble showing $$\lim_{n\rightarrow\infty}\frac{n}{(n!)^{1/n}}=e.$$


Cannot create an array of LinkedLists in Java...?

I'm working on a sparse matrix class that needs to use an array of LinkedList to store the values of a matrix. Each element of the array (i.e. each LinkedList) represents a row of the matrix. And, each element in the LinkedList array represents a column and the stored value.  In my class, I have a declaration of the array as:  private LinkedList<IntegerNode>[] myMatrix;   And, in my constructor for the SparseMatrix, I try to define:  myMatrix = new LinkedList<IntegerNode>[numRows];   The error I end up getting is     Cannot create a generic array of LinkedList<IntegerNode>.   So, I have two issues with this:   What am I doing wrong, and Why is the type acceptable in the declaration for the array if it can't be created?   IntegerNode is a class that I have created. And, all of my class files are packaged together.


I want to create a table in LATEX using tikz and I want to fill text into the table. I tried to do it with nodes, but the nodes overlap and so the text is not displayed correctly.  Is it possible to define a node such that it moves (automatically) below according to how much text I enter in the node above?  Here is my try:  \documentclass[a4paper, 11pt]{article} \usepackage[a4paper,left=3cm,right=3cm,top=3cm,bottom=3cm]{geometry} \usepackage{amsfonts} \usepackage{amsmath} \usepackage{amssymb} \usepackage{amsthm} \usepackage{clrscode} \usepackage{enumitem} \usepackage{fancyhdr} \usepackage[T1]{fontenc} \usepackage{graphicx} \usepackage[utf8]{inputenc} \usepackage{latexsym} \usepackage{lmodern} \usepackage{mathtools} \usepackage{mdframed} \usepackage{pgf} \usepackage{tcolorbox} \usepackage{tikz} \usepackage{tikzpeople} \usepackage[absolute,overlay]{textpos} \usepackage{xcolor}      \usetikzlibrary{arrows} \usetikzlibrary{positioning}  \usetikzlibrary{shapes.multipart} \usetikzlibrary{shapes.geometric}  \tikzstyle{process} = [rectangle, minimum width=3cm, text width=3cm, minimum height=1cm, text centered, draw=black, fill=orange!30] \DeclareGraphicsExtensions{.pdf,.png,.jpg, .tif}  \pagestyle{fancy} \fancyhf{} \renewcommand{\headrulewidth}{0pt} %\fancyhead[LE,RO]{Overleaf} %\fancyhead[RE,LO]{Guides and tutorials} %\fancyfoot[CE,CO]{\leftmark} \fancyfoot[LE,RO]{\thepage} \renewcommand{\familydefault}{\sfdefault}  \begin{document}     \begin{tikzpicture}[node distance = 1cm]         \node[process](step1){Step 1 \\ AAAAA \\BBBB \\CCCC};         \node[process, below of=step1](ste2){Step 2};     \end{tikzpicture}     \end{document}


what is the best way to Implement a counter in Java 8?

I tried to implement a counter using Java 8's LocalTime and Instant, both works fine but the output is a bit confusing! when ever I use Instant I got smaller values for the same loop ? any idea?  // using Instant  Instant before=Instant.now(); // something time consuming for(int i=1;i<100000000;i++); Instant after=Instant.now(); Duration duration=Duration.between(before, after); System.out.println(duration.toMillis());   // using LocalTime LocalTime xBefore=LocalTime.now(); for(int i=1;i<100000000;i++); LocalTime yAfter=LocalTime.now(); System.out.println(ChronoUnit.MILLIS.between(xBefore, yAfter));


Word for instance of faux pax redundancy?

I subscribed to a word-of-the-day thing about 10 years ago. One of the words was a noun for the instance of describing something redundantly. Every now and then I hear someone do this and die not being able to remember the word for it. As luck would have it, I can't muster an example I feel very confident about but perhaps "it was too overdone" where "it was overdone" would suffice would suffice as an example...    My ears will explode if I hear one more _____ out of this non-EL&U-subscribing scrub.


my la/ptop keeps on thi/nk/ing/ th/at I am hol/ding/ own the // k/e/y/////////////////////////////////

thi/s is relly g/etting/ in th/e way of thi/ng/s. It does it by it/self about /every thi/r/ty seconds/ or less, and goes on until a new key is h/it - several keys trig/g/er is /as well ing/lduing/// gh esc \ up //////////////////////////// th/ere are other k/eys which /trig/g/er it too. It is only ever/ the / it thinks is being held down. Sometimes it doesn't happen and everything seems to be fine for a while too. They keyboard is clean, nothing has been spilled on it either - my laptop thinks it is clean of virus' and that it's hardware is working fine.   I can ho/nestly say I'm/ at my wits end, because it h/appens so often I can'/t/ /even fix th/em fr/om my typing/. /////////  it/ //h/appened a few /month/s /a/g/o and th/en stopped f/o/r /a few month//s with/ no apparent cha/ng/e to anyth/ing/.


I just stumbled upon a  starting with      Hello friendly SO ppl,   I am more or less a CSS noob; and for the life of me, I can't solve this issue. Hopefully this will be easy for one of you awesome people.   and ending with     Thanks a bunch for your help.   While I do not consider this a big issue, I often see phrases like the above which do not really add anything to the question - is it okay to edit them away?    By the way: The above really just was a random example.


Writing systems of linear equations and matlab help appreciated

Does anyone know how I would go about answering the following question?  A traffic engineering company has installed some trac cameras along a one lane road to find a relation between the number of cars passing the road and the average speed at which the cars move. The cameras show that:   Point 1: When there is 1 car passing the road, the average speed is 50km/h. Point 2: When there are 5 cars passing the road, the average speed is 45km/h. Point 3: When there are 12 cars passing the road, the average speed is 38km/h.   The traffic engineering company decides to model the average speed (shown by $u$) as a linear function of the number of cars (shown by $n$). So we want to have  $$u(n) = \alpha + \beta n.$$   Using Point 1 and Point 2 information, write the system of linear equations to calculate $\alpha$ and $\beta$. Write a MATLAB code to calculate $\alpha$ and $\beta$.


Ubuntu 17.10 and later: Don't suspend when lid is closed, just lock screen

Since my upgrade to Ubuntu 17.10 there's no option in the settings about what to do when the notebook-lid is closed any more.     Before this function had the options "do nothing" and "suspend" and maybe "shutdown".  The "do nothing" function did something: when the lid was closed, the display went dark and the screen was locked with the password.  My question is how to change the setting so that it's like I'm used to, so that the screen just locks but doesn't suspend when closing the lid.


How do I remove an empty element in an array?

I have an array of email address, but an empty string gets injected into the end of the array. How can I remove this element in the array?   for(int i = 0; i < allToAddresses.Length; i++) {     if(allToAddresses[i] == " ") // find where empty element is     { //Here i am trying to delete that empty element. does not work        allToAddresses[i].Split("".ToCharArray(),StringSplitOptions.RemoveEmptyEntries);     } }


Referencing equation counter value in custom float caption

I have used the float package to create an equation float, eqfloat, so I can add captions to equations. Within the eqfloat I used the equation environment to typeset the math.  I want to keep the right hand arabic numbering within parentheses that is added by the equation environment but I also would like the eqfloat caption below the equation to use the same number as the equation environment.  The following code achieves this by making the eqfloat use the same counter as the equation environment and then manually adjusting the equation numbering within each eqfloat.   Is there a better way to make the eqfloat caption reference the current value of the equation environment counter?  Is it possible to prevent the custom float environment from increasing the counter and only to reference the current value of the equation counter?  \documentclass[a4paper]{article}  \usepackage[margin=25pt, labelfont=bf]{caption} \usepackage{amsmath, amsfonts, pifont, float, color, url} \usepackage[pdftex, plainpages=false, pdfpagelabels, bookmarks=true]{hyperref}  \newfloat{eqfloat}{h}{eqflts} \floatname{eqfloat}{Equation} \makeatletter \let\c@eqfloat\c@equation \makeatother  \begin{document}     ...     \begin{eqfloat}         \begin{equation}             E = mc^2         \end{equation}         \addtocounter{equation}{-1}         \caption{Equation caption here.}         \label{eq:example}     \end{eqfloat}  \end{document}


I installed Ubuntu 12.04. I erased a GRUB file by mistake, now grub rescue doesn't let me do anything. I used Boot Repair, and now my PC is stuck at:  error: invalid arch independent ELF magic. grub rescue>   I used Boot Repair, but it looks like my laptop can't detect my USB drive, also I can't access the BIOS.


How do I upgrade from Ubuntu 12.04 to Ubuntu 13.04 with an .ISO image?

I have Ubuntu 12.04 installed on my system. I want to upgrade it to Ubuntu 13.04. I want to do this upgrade using an .ISO image of Ubuntu 13.04 and without a USB drive.  I tried  .  But it didn't work for me.  After running the proposed commands, I didn't have any alerts about updating. I also don't understand the gksu part of the solution.  Also, is this possible to do by using a networked computer? By this I mean the .ISO file is on another computer.


what is a phrase for something that is detrimental but is also a solution for the problem?

what would be the suitable phrase for something that is bad but is also a solution for the problem? for example if I say internet has brought cyberterrorism but is also very useful for  countering terrorism.


Modulo calculation with inverse and larger divisor

I have this equation $x \equiv (2003^{-1}) \mod 1511$ and am confused with how to try solving it. Since $2003^{-1} < 1511$, you can't use the extended Euclidean algorithm with regards to the inverse. So I'm looking for some tips on where to start with solving this equation. Thanks.


If $A$ and $B$ are $3 X 3$ real matrices such that $rank (AB) = 1$ ,then rank (BA) _______?  since $rank (AB) =1    |AB|=|A||B|=0$  It implies, atleast |A|=0 or |B|=0  Hence, $rank (BA)$ cannot be 3.  and ,also there is a result   $rank (A) + rank (B) -3\leq rank(AB)\leq min(rank (A) , rank (B) )$ $rank (A) + rank (B) -3\leq rank(BA)\leq min(rank (A) , rank (B) )$ from above it gives rank (BA) is 1.


Open chrome and launch the settings page

Does anyone know how to launch chrome and immediately open a "chrome url"?  I'm trying to make a shortcut like this, but its not working when I tried. it only accepts http:// urls  GoogleChromePortable.exe "chrome://settings/"   Thanks in advance who can help out


n= 29, p value for three tests: .061, .09 and .13 but all trending in predicted direction: How to report?

So I ran three paired samples t-tests to see if people did a certain action more after hearing a target stimulus. my prediction is that they would do the action more. All tests were one-tailed as i was only looking at one direction: did it increase after x. n = 29 for each test. the p values for tests were, First test:.061, one-tailed, Second test:p = .098, one-tailed and third test: p = .13, one-tailed. But in every result the mean was higher in the group I predicted would be higher after the stimulus. So, when I report this what can I say? Should I say that while not 'significant' they were in the 'expected direction' and that repeating the test with a larger sample is needed? In other words that there is an interesting trend and deserves more investigation? Thanks so much!


When and how is javascript eval() vulnerable to injection?

I've got a new team member joining us, and while I was looking at his code, I noticed he uses a lot of eval(). I've read a million times that eval() is evil, vulnerable to injection, but can be used for good, and is sometimes the right solution. Unfortunately, everything I've found on the subject is on how to use it correctly when you're writing code, which makes determining if existing code is a security risk difficult to do.  How do I determine if use of eval() is correct or risky?  Here are two examples of uses of eval that look potentially risky to me.  1.  if (sizzleURL) {     message = {         type: "GET",         url: sizzleURL,         async: false,         oncomplete: function(result) {             function define(definition) {                 self.Sizzle = definition()             }             define.amd = true;             eval(result.responseText)         }     };     ajaxService.sendRequest(message) } else {     // ect }   2.  json: (function() {     if (typeof window.JSON !== "undefined") {         return {             serialize: window.JSON.stringify,             parse: window.JSON.parse         }     }     return {         serialize: serializeToJSON,         parse: function(data) {             return eval("(" + data + ")")         }     } }())   If these are secure uses of eval, or if you cannot tell from this small context, please explain how and where eval injection works.


Is Sentinel's third effect an opportunity attack?

Sentinel   When a creature within 5 feet of you makes an attack against a target other than you (and that target doesn’t have this feat), you can use your reaction to make a melee weapon attack against the attacking creature.   Does it count as an opportunity attack for the purpose of reducing their speed to 0?     When you hit a creature with an opportunity attack, the creature’s speed becomes 0 for the rest of the turn.


I have 5 files called file1, file2, file3, file4, file5, . I am attempting to run the following command echo "contents" >> file{1,2,3,4,5}. I get the following error when I run this command; -bash: file{1,2,3,4,5}: ambiguous redirect. My goal is to echo some text to multiply files in one command. How can I achieve this? Thanks in advance.


Why does the median minimize $E(|X-c|)$?

Suppose $X$ is a real-valued random variable and let $P_X$ denote the distribution of $X$. Then $$ E(|X-c|) = \int_\mathbb{R} |x-c| dP_X(x). $$  of $X$ are defined as any number $m \in \mathbb{R}$ such that $P(X \leq m) \geq \frac{1}{2}$ and $P(X \geq m) \geq \frac{1}{2}$.  Why do the medians solve $$ \min_{c \in \mathbb{R}} E(|X-c|) \, ? $$


I am attempting to run sublime text on my ubuntu terminal on Windows 10. I successfully downloaded according to the instructions here (). When I run commands such as subl --help, I see the expected list of commands.   However, when I look to open a file with subl filename.py, I receive no error message but nothing happens. I have looked around online and have not seen this problem come up. I am not sure why this is happening but would appreciate any help.


How to determine which program is making a certain sound in windows 7?

I'm experiencing an annoying "female robotic" sound effect saying "loading complete" at uncertain interval in windows 7.  I want to shut down that noise for good. To do that, I have to determine which program is making this sound. I tried to open the "sound mixer" window, only to find to program last made any sound, one is official GTalk client, one is system sound. I tried to close GTalk and the sound still existed.  I started experiencing this issue not long after I installed a "driver" program for Rapoo E9198 wireless keyboard.


How do Black Bodies Absorb and Emit Radiation?

I have learnt how the gases of elements are able to absorb only certain wavelengths of EM radiation corresponding to the energy transitions between energy levels of orbitals. Furthermore, these excited electrons are able to fall back to lower energy orbitals to release certain wavelengths of radiation.    I have also learnt that perfect black bodies absorb all wavelengths of radiation and emits radiation and how hot, glowing solids and liquids can be modelled as black bodies. However I don't understand how black bodies are able to absorb all wavelengths of EM radiation.   For example, I can't understand how a piece of hot iron (which can be modelled as a black body) can absorb every single wavelength of EM radiation that falls upon it if only certain energy transitions are allowed by electrons. I understand that there are more transitions possible than just electronic transitions, such as vibrational and rotational transitions. However I don't believe that this is able to result in all wavelengths of EM radiation to be absorbed.  Further, for the same reason I am not sure how black bodies are able to produce a continuous spectrum (emit all wavelengths of light) if only certain energy transitions are allowed.  Note: I am aware a similiar question has already been asked: , however it didn't answer my question.


I am using msysgit from behind a proxy. As I said in question   I have set system variable http_proxy to a value. Later I call  git config --global http.proxy $http_proxy   However, if I call something like:   git clone git://git.savannah.gnu.org/gnuprologjava.git   It gives the following error:  git.savannah.gnu.org[0; 140.186.70.72]: errno=No error fatal: unable to connect a socket (No error)


Profile tab hyperlink should match name change

The recent user profile tab name change - from "activities" to "all actions" - was not accompanied by a hyperlink update from ...?tab=activities... to ...?tab=allactions...    Click on the "posts edited" link to see the 404-error.


Rigorous textbook about special relativity

I want textbooks about special relativity that demonstrates  the relativistic phenomena  by deep details


Is it typical for self-answered questions to be downvoted?

As a habit, I have always tried to answer my own questions on Stack Overflow and other sites if no one provided an answer, and I later found the answer myself. I consider this to be essential to helping other developers in the future. Some examples:  Lack of support of TailwindCSS in webkit browsers  Vim replace regex command  Material theme lack of support for dark theme   I'd admit that many of the original questions I answered were not the best questions. They were often the result of poor research and/or I could have found the answers if I looked hard enough into documentation for long enough. What I would like to stress, however, is that my impression of SO is a site of sharing knowledge. I would really not mind if my questions were downvoted, because of their lack of merit. What I do not understand is why it seems like knowledge-sharing through self-answering is starting to become discouraged.


What is the exact difference between "into" and "onto"?

How to use "into" and "onto" in sentences ? Can we use "onto" in any sense while talking of people and if yes, how ? Do these two quoted words have a common usage anywhere ?


Proving that a set is countable by finding a bijection

$Z$ is the set of non-negative integers including $0$. Show that $Z \times Z \times Z$ is countable by constructing the actual bijection $f: Z\times Z\times Z \to \mathbb{N}$ ($\mathbb{N}$ is the set of all natural numbers). There is no need to prove that it is a bijection.   After searching for clues on how to solve this, I found $(x+y-1)(x+y-z)/z+y$ but that is only two dimensional and does not include $0$.  Any help on how to solve this?


How can I SQL insert a record for every id in another table?

I've seen the insert select but I only want to get one value from the second table.  Here's what I'm thinking:  insert into table1 Values((select distinct id from table2), "blah", "blah", "blah")   So after the Id, the rest of the values will be hard coded to whatever I want.  Is this possible?


Can't get rid of that white-alpha-border!

If I press the "include alpha-button" in the Mix-Color-Node, I get white borders. Otherwise i've got a perfect alpha but no blue background.


Transferring Windows XP Mode VM to Another Machine?

I've been running Windows XP mode on my Windows 7 Laptop for a while now and I've got my VM set up just how I like it.  I am switchign laptops due to an intermittent hardware failure. Is it possible to transfer my Windows XP mode VM to my new laptop?  I know it's just a Windows Virtual PC VM, how would I go about transferring it if this is possible?  Will the Fact that I'm moving from Windows 7 Ultimate to Windows 7 Pro make a difference? AFAIK they both support Windows XP Mode.


How to connect my Android phone in USB Debugging mode?

In windows, I used to connect my phones (Samsung Galaxy S3 I9300 & Samsung Galaxy Note3 N9005) to my PC after installing the USB driver, and  enable USB Debuggng in the phone and debug my applications using the Android Studio. I installed the Android Studio on Ubuntu but I don't know how to install the driver or how to connect my phone in debugging mode. when I connect the phone I can read the phone as a storage.


Relatively new Java programmer and I've been taught that you can't create an instance of an abstract class. I've also done a little research and I learned that in most cases when it appears an abstract class is being created, it is actually an anonymous subclass. But here is the issue I ran into:  Java's URL class has a method openConnection that returns a URLConnection. URLConnection is an abstract class, and the Java documentation also lists all of its subclasses as abstract..... so I'm really lost. What's being returned?


When Marty travels back to the future, why are not there two of him in 1985? Or they indeed are?

When Marty travels back to 1985 from 1955 at the end of the 1st BTTF movie (and meets his all new present), aren't there two Marties in that moment (the one that has just arrived and the one that was born thanks to his collaboration in making their parents to fall in love one with each other in 1955)? If not, why?


I'm looking for an explanation of how a hash table works - in plain English for a simpleton like me!   For example, I know it takes the key, calculates the hash (I am looking for an explanation how) and then performs some kind of modulo to work out where it lies in the array where the value is stored, but that's where my knowledge stops.  Could anyone clarify the process?  Edit: I'm not asking specifically about how hash codes are calculated, but a general overview of how a hash table works.


I'm using Popcorn.js and it creates the following HTML code:

Hello

   But now I'm trying to add/remove .myClass to .test using jQuery when the div inside of #row1 is display: inline.  I've tried .height(), .lenght() and .width() (but this one doesn't work, because the width of the div is always 1246px)  Any help would be greatly appreciated!  ** EDIT **  The whole HTML code:


generate password that is random length between 8 - 16 ( i have the generator but its not dynamic)

This is my password generator and it generates 8 characters and shuffles them. But i need to make it dynamic length. How would i go about doing that. So the output would be different length between 8 - 16 characters.  if [ $# -eq 0 ]; then num=("0" "1" "2" "3" "4" "5" "7" "8" "9") special=("@" "#" "$" "%" "*" "-" "+") upper=(A B C D E F G H I J K L M N O P Q R S T U V W X Y Z) lower=(a b c d e f g h i j k l m n o p q r s t u v w x y z) lower2=${#lower[*]}   #${lower[$((RANDOM%lower2))]} upper2=${#upper[*]}   #${upper[$((RANDOM%upper2))]} num2=${#num[*]}     #${num[$((RANDOM%num2))]} special2=${#special[*]} #${special[$((RANDOM%special2))]}  echo "${special[$((RANDOM%special2))]}${num[$((RANDOM%num2))]}${lower[$((RANDOM%lower2))]}${upper[$((RANDOM%upper2))]}${lower[$((RANDOM%lower2))]}${upper[$((RANDOM%upper2))]}${lower[$((RANDOM%lower2))]}${upper[$((RANDOM%upper2))]}" | fold -w 1 | shuf | tr -d '\n' echo fi


I updated LyX to 2.3.0-1, and found that LyX was displaying all the "-" characters in Math Mode as "\lyxminus". No such problem occurs when entering outside of Math Mode. LyX also seems to have no problem compiling to TeX, and the PDF output looks normal.  I removed and re-installed LyX, and this issue was still there.   Does anyone have any ideas on what might be going on? I am using Linux Mint 18.2 Sonya.  Note: I previously saw this question ask about the same thing, but the author appears to have deleted their post:


JPA and Hibernate - Criteria vs. JPQL or HQL

What are the pros and cons of using  or ? The Criteria API is a nice object-oriented way to express queries in Hibernate, but sometimes Criteria Queries are more difficult to understand/build than HQL.   When do you use Criteria and when HQL? What do you prefer in which use cases? Or is it just a matter of taste?


I just learned about Random Variables and Expected values and i tried solving the following question from my textbook  In an urn are N white balls. The balls are arbitrarily taken and at the same time a similar red ball is placed in the urn. So the number of balls in the urn has not changed. The same process is repeated until all N balls in the urn are red. Let X be the number of withdrawals made. Calculate the expected value of X  I'm having real struggles to Modell this problem correctly,  i tried via diffrent distribution concepts but non of them worked. Could someone give me some details on how to structure this problem


Dropped camera, now lens won't attach to body - How much for repairs?

I dropped my Nikon D3200. Camera still turns on, but the lens wont attach to the body. It looks like something at the bottom of the lens might be broken; not the actual lens, but a small black circle type of thing. Anybody has any idea how much something like that will cost to repair?


Calculating a Factorial Base Representation

My friend thought of a system in which each number $n$ (I will first restrict my question to positive integers $n$) is represented by a digit string $(d_l,...,d_1)$ as follows $\forall n \in \mathbb{N}, \exists l \in \mathbb{N}: n = (d_l, d_{l-1}, ..., d_2, d_1) = \sum_{i=1}^l (d_i*(i!))$ where $\forall i \in \mathbb{N}, d_i \in \mathbb{N}: d_i \leq i$ and specifically $\forall i>l, d_i = 0$ ; note that each integer $d_i$ would be represented in decimal with at least 1 digit (in general, these factorial digits can be quite long in decimal representation)- but this is not an issue at the moment [because his system uses a finite alphabet via balanced quinary for each $d_i$].  [In this post, any number shown is in decimal.]  For example, $$1729=2*6! + 2*5! + 2*4! + 1=(2,2,2,0,0,1)$$ and $$1729^3 = (10*12!+9*11!+5*10!+3*9!+6*8!) + 1729 = (10, 9, 5, 3, 6, 0,2,2,2,0,0,1)$$.  My question is: how would this digit string $(d_l,...,d_1)$ be computed most efficiently for general positive integer n? I have mostly just been trying to guess at the largest $l \in \mathbb{N}: l*(l!) \leq n, (l+1)! > n$ and then (once I have found it), I just go through digit-by-digit, working my way down in values of candidate $d_i$ (mostly by squeeze theorem with the goal of finding out that $d_i + 1$ is too large first and then next testing $d_i$ and finding that it works). This process can be quite arduous. What would you recommend doing, algorithmically and efficiently? Bragging rights for Mathematica code that automates the process.  (Using Stirling's formula might be helpful, but it still requires a lot of playing around.)  What modifications would need to be made for general real numbers (including nonintegers)? After the radix point, it works similarly, but with $(i!)^{-1}$ (where, I think, $d_i<i \forall i \in \mathbb{N}$ and where the first such base is $\frac{1}{2!}$).  More generally and philosophically, are there any spiritual problems with this representation? It is meant to be rather compact and alien. What are some cool properties that it exhibits?


I'm wondering how to determine the closed form for this sum: $$\sum_{k=1}^n k 2^k$$  I'm aware that it is $ 2 (2^n n - 2^n + 1)$ through Wolfram|Alpha, but I wonder how this would be done by hand. Searches for "summations of products" yielded no results, so I'm assuming that there isn't an easy way to determine summations that include products of functions.  How would one approach computing this summation without the help of technology?


I'm currently a Physics major undergrad. I was wondering if you could recommend Statistical Mechanics books. At my university, we work with Concepts in Thermal Physics by Blundell, but I always prefer to have several books to consult before getting to a course.


I've been trying to get a ubuntu linux distro working on my computer the past day or two, and have everything working fine, except for my wireless card. I used the command  lspci -nn | grep 0280   and the response I got was   04:05.0 Network controller [0280]: Broadcom Corporation BCM4318 [AirForce One 54g] 802.11g Wireless LAN Controller [14e4:4318] (rev 02)   Anyone know why I'm fine with Wired connections, but Wireless doesn't even find my network?


With System.Data.SQLite how do you specify a database file in the connect string using a relative path

Wanting to deploy my project on different servers I would prefer to be able to specify a connect string using a relative path. I can't seem to get that to work and want to know if there is some trick to it...?


Facing difficulty in initializing list in python with some values

I have attached my python code below where I am facing some difficulty in initializing list with some values please take a look at it:- array = [1, 2, 3, 3] value = 6 dp = [[-1] * (value + 1)] * (len(array) + 1)     for i in range(len(array) + 1):     for j in range(value + 1):         if i == 0 and j > 0:             dp[i][j] = 0         elif i >= 0 and j == 0:             dp[i][j] = 1         else:             dp[i][j] = -1   for i in dp:     for j in i:         print(j,end = " ")     print()  The output which I am getting is :- 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 -1 -1 -1 1 -1 -1 -1 -1 -1 -1  The output which I am expecting is:- 1  0  0  0  0  0  0 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 -1 -1 -1  can you guys please figure out where I am going wrong as I am learning to use python stuffs.


Biblatex: Standard way to cite a volume of a series in a collection

Is there a standard way to cite a volume of a multi-volume series that appeared again in a multi-volume 'collected works' edition.  Like, I wanna cite 'Volume 6 of Series 6 of the collected Works of G.W. Leibniz'. There are 53 volumes total, but for each series, the numbering starts again from 1. So, the Output should be sthg like that: Akademie Edition, Ser. III, Vol. IX, p256  I could solve it with using shorthands, I guess. my .bib file so far Looks like that:  EDIT: MWE  \documentclass[12pt]{article}  \usepackage[ backend=biber,  style=verbose]{biblatex}  \begin{filecontents}{\jobname.bib} @mvbook{A, Author = {Leibniz, Gottfried Wilhelm}, Title = {S{\"a}mtliche Schriften und Briefe}, Volumes = {53}, Year = {1923-}}  @book{A:VI:vi, Author = {Leibniz, Gottfried Wilhelm}, Maintitle = {S{\"a}mtliche Schriften und Werke}, Series = {Philosophische Schriften}, Number= {6}, Title = {Nouveaux Essais}, Volume = {6}, Year = {1962}} } \end{filecontents} \addbibresource{\jobname.bib} \begin{document} \section{Title}  \cite[123]{A}  \cite[123]{A} ***  \volcite[c.f.]{2}[123]{A}  ***  \cite[123]{A:VI:vi}  \cite[123]{A:VI:vi}  \printbibliography \end{document}


I was just using the "Search all Sites" feature (), and there seem to be several problems with the UI. (I'm using Ubuntu 16.02 + Firefox 64.0 at the moment, but it also fails in the same way on Windows 7 + Chrome 71.0.)  The options at the bottom don't work:   It seems to default to 30 results per page. If I select 50, then "next page", it reverts back to 30. If I "next page" a couple of times, and then select 50 again, it reverts back to page 1.   Obviously, these "state changes" are not being propagated correctly from page to page.  It all works correctly in a site-specific search (e.g., StackOverflow). I note that the style of the controls is different here, so it's probably a different set of code.  This expands on the existing question  (which doesn't have an answer) by pointing out that changing the page size also resets the page index. That one should probably be made a duplicate of this one.


Which Time Tracker application do you recommend?

I have to do three or four jobs a day, and each has several parts. I want a time tracker tool to help me know how much time I've spent on each part and each job overall.   I've found some like gnotime and hamster.  What application do you recommend for such a case?


$ g: [0,\infty[ \rightarrow R, a \rightarrow \int_{0}^{\infty} e^{-ax} h(x) dx$ is defined, continious.., if h is lebegue-measurable

Show that for a borel-measurable-lebesgue-integrable function $h:[0,\infty] \rightarrow \mathbb R$ the function $ g: [0,\infty[ \rightarrow \mathbb R, a \rightarrow \int_{0}^{\infty} e^{-ax} h(x) dx$ is 1. properly defined, 2. continuous and 3. evaluate the integral for $a \rightarrow 0$. We are taking the lebesgue-measure on $\mathbb R$.  I think (but I would gladly take a reasoning for that) $e^{-ax} h(x)$ is measurable, meaning that I can look at $ \int_{0}^{\infty} |e^{-ax}h(x)|dx$, which is defined. Since $|e^{-ax}| \le 1$, we get $|e^{-ax}h(x)| \le |h(x)|$ and so we get $\int_{0}^{\infty} |e^{-ax}h(x)|dx \le \int_{0}^{\infty} |h(x)|dx < \infty$ ($g$ is integrable). Therefore $\int_{0}^{\infty} |e^{-ax}h(x)|dx < \infty$, resulting into the integrability of $g$, so that $g$ is finite and therefore defined.  Does is make sense?  I have no idea, how to show, that $g$ is continious. I need help there.  If I could take the limit into the integral, then the result should be the Integral over $h(x)$. But I don't know here either, how to reason that.


SSH - Diffie-Hellman; prime & g exchange

The Diffie-Hellman key exchange algorithm can be used with SSH. But how does SSH exchange the large safe prime p and the generator for a subgroup of GF(p) g? According to RFC 4253 the first steps are to send e & f which are calculated depending via:  e = g^x mod p  f = g^y mod p  Now x & y are randomly generated but how do both parties come to the same values of g and p? There seems to be no exchange happening of them. Does anybody have an explanation for this?


Could one or more black holes be used to pull something out of another black hole?

Could a second black hole be used to create a gradient that reaches into the event horizon of a first black hole so that what's inside it can escape through the gradient?  Maybe you would have to use a lot of black holes and be able to plot or control their position precisely.


Is it possible to transfer kinetic energy from rigid body 1 to body 2 and conserve total kinetic energy?

This question comes from working with rigid rolling disks and wheels. For example, when a rotating disk comes in contact with a non-rotating disk, the non-rotating disk will start to rotate due to friction creating a torque on the body.   So if we just look at two rigid bodies, and forget about air resistance and other forces acting on the system of two bodies, is it in the theoretical case possible to transfer some or all of the kinetic energy of body 1 to body 2 without losing energy, in the form of friction, sound and heat, in the process? Does it make a difference in the result, if the kinetic energy of body 1 is pure rotational energy or translational energy or a combination of both?   To be clear, body 2 should have gained some or all of body 1's kinetic energy while the total kinetic energy of (body 1 + body 2) is the same.


How i will able to close these windows at right. please give me a answer.


Using the basics: Array Descending Order?

Were now on arrays and the job is to do a list of numbers and then it would show the descending order of those numbers.  Here's the condition: A Nested Loop and a Decisive Structure.  I wasn't able to use this code:    for (iLoop = iNumber.length - 1; iLoop >= 0; iLoop--){             System.out.println("" + iNumber[iLoop]);     Because it wouldn't show a nested loop one nor any decisive structures.  I can't use any sort of method YET. Only the first for loop will do the loop for the array. Here's my code next:            int iX, iY, iLoop;         Scanner var = new Scanner(System.in);         int[]iNumber = new int [10];         for (int iIndex = 0; iIndex < iNumber.length; iIndex++){             System.out.print("Enter a number: ");             iNumber [iIndex] = var.nextInt();         }         for (iX = 0; iX < iNumber.length; iX++){             for (iY = iX + 1; iY < iNumber.length; iY++){                 if (iNumber[iX] < iNumber[iY]){                     iLoop = iNumber[iX];                     iNumber[iX] = iNumber[iY];                     iNumber[iY] = iLoop;                 }             }         System.out.println("" + iNumber);         }     } }     Now, I can't now think why the output is:    [I@1909752 [I@1909752 [I@1909752 [I@1909752 [I@1909752 [I@1909752 [I@1909752 [I@1909752 [I@1909752 [I@1909752     I don't know what to do again. Someone help me, thank you in advance.


The letter A appears an even number of times. How many different sequences could Dr. Lizardo have written down?

Dr. Lizardo writes down a sequence of $n$ letters, where each letter is A, B, or C, and the letter A appears an even number of times. How many different sequences could Dr. Lizardo have written down?   What I have tried so far The last letter is predefined in terms of "A or not" based on the first $n-1$ letters. If there are an odd number of As so far, the last one has to be A, otherwise, B or C. Therefore, there are $3^{n-1}$ ways to write the first $n-1$ letters. However, the last letter can either have 1 choice or 2 choices. I am thinking maybe we need to do $S_n = 3^{n-1} + S_{n-1}$. However, I need a closed form, not a recurrance. How can I do this? Thank you!  Note: $S_n = 3^{n-1} + S_{n-1}$ seems to be working for the first few values of $n$ (I tested through $n=4$), so finding a closed form of that recurrance would work as well.


When voting to close and migrate to another site, how can I add another site?

When voting to close (or in such cases migrate) a question:  Community specific What site does this question belong on?  expatriates.meta.stackexchange.com   Here one site is given, but I would like to suggest  law.stackexchange.com  but there isn't any way to add this suggestion to the migration list.


Exporting coordinates of vertices to CSV

I have a  which I import into Blender.    Now what I'm trying to do is to export the coordinates of vertices into a .ply file. When I export these vertices into a .ply file they are not correct. It seems that it only exports the coordinates of the single face which you can see in the picture. How can I export those vertices correctly?  EDIT The .csv structure:  1;2;3\n  4;5;6\n  ... Each column is separated by a semicolon and each row by a new line.


I am getting an error while running following code:  public class TestClass {  public static void main(String[] args) {     var list = new ArrayList<String>();     list.add("Harry");     list.add("Marry");     list.add(null);     list.add("Larry");      list.removeIf(e -> e.startsWith("H"));     list.forEach(System.out::println);      } }   Getting following error:  Exception in thread "main" java.lang.NullPointerException at test/test.TestClass.lambda$0(TestClass.java:14) at java.base/java.util.ArrayList.removeIf(Unknown Source) at java.base/java.util.ArrayList.removeIf(Unknown Source) at test/test.TestClass.main(TestClass.java:14)   Why I am getting the unknow source error, it  works fine if I provide following lambda:  list.removeIf(e -> e == null);


The dog started barking after the thief had left the place six months ago

It is like a dog barking six months after the thief  left.   This  is an  Indian Idiom and is used when someone fails to do their duty at the right time and makes unnecessary fuss very late after the dangerous event happened long ago.  I believe that the question about the idiom has not been asked earlier.  I would like to know an almost equal idiom in English.  This is not at all a duplicate of the previous post and even the answers do not solve my problem. The previous post asked for something that means one needs to make a habit of doing things regularly otherwise they fail to  do things at the right time.  Dog stands for faithfulness but rarely fails to bark at a thief instantly but it surprisingly not only failed to do its duty but barked unnecessarily after the thief left the place long ago which is inexcusable.


Linear regression - the use of count data

I hope that you do not mind helping me with this likely quite simple problem I am having. Can linear regression be used for count data? If not - do you know why do universities, as well as online courses and youtube videos, teach linear regression while presenting use cases with count variables? Your help is much appreciated :) Thank you and good day. Thank you.


Spec of infinite product of rings is not an infinite disjoint union

For commutative rings $A_1,...,A_n$ we have that  $$ \operatorname{Spec} (A_1 \times \cdots \times A_n) \simeq \operatorname{Spec} A_1 \sqcup \cdots \sqcup \operatorname{Spec} A_n .$$ My question is, whether we have a similar identification for an infinite product of rings.  My guess is that the answer is no. I would argue like this:  For $n \in \mathbb N$, let $k_n$ be a field and consider the scheme $X = \bigsqcup_{n \in \mathbb N} \operatorname{Spec}k_n$. Topologically, this is a disjoint union of points, and it should hence carry the discrete topology. But then, $X$ cannot be affine, as affine schemes are quasi-compact, but the open covering $X = \bigcup_{n \in \mathbb N} \operatorname{Spec} k_n$ does not admit a finite subcover.  Is this ok? If so, can one generalize the statement for finite products to something similar for infinite products?


Why does strcmp() return 0 when its inputs are equal?

When I make a call to the C string compare function like this:  strcmp("time","time")  It returns 0, which implies that the strings are not equal.  Can anyone tell me why C implementations seem to do this? I would think it would return a non-zero value if equal. I am curious to the reasons I am seeing this behavior.


I had my first loose leaf tea today. Black tea, with pieces of dried fruit in it. As I was throwing the used leaves away, I noticed what seemed to be a dead worm. Is this at all common and safe, or should I get rid of the tea?