Q. If you compile and execute an application with the following code in its main() method: Why " s" is created two objects
How do I compare strings in Java?
Let $\mathbb{F}$ be a finite field.  Let $a_1,\dots,a_n \in \mathbb{F}$ be given.  I want to know whether there exists $x_1,\dots,x_n \in \mathbb{F}$ such that  $$a_1 x_1^2 + a_2 x_2^2 + \dots + a_n x_n^2 = 1.$$  My question: Can we characterize when this equation has a solution, i.e., by some criterion on $a_1,\dots,a_n$?  Is there a clean characterization, in terms of $a_1,\dots,a_n$ and the properties of $\mathbb{F}$?    Here's what I can see immediately.  First, if $n=1$, there is an easy answer (the equation has a solution iff $a_1$ is a square in $\mathbb{F}$).  Second, if any $a_i$ is a square in $\mathbb{F}$, the equation has a solution (set all other $x_j$'s to $0$), so we can assume that all the $a_i$'s are non-squares and that $n \ge 2$.  Third, if $-1$ is a square in $\mathbb{F}$, then the equation has a solution: we can take $x_2 =  \sqrt{-a_1/a_2} \cdot x_1$.  But what about the case where $-1$ is a non-square in $\mathbb{F}$?  Is it always guaranteed to have a solution in this case? Extract date from a variable in a different format Let me explain you the problem   $ date +%c -d "$d" Tue 31 Dec 2013 01:13:06 PM CET $ date +'Today is %F' -d "$d" Today is 2013-12-31   This solution corresponds to current date.  But I have one variable which stores date other than current date  $Prev_date="Wed Dec 25 06:35:02 EST 2013"    I am looking for solution to read this date as 2013-12-25 and store it in a variable.  I have tried this:  a=`date --date=$Prev_date '+%y/%m/d'` echo $a   It's giving this error:  date: illegal option -- date=Wed usage: date [-u] mmddHHMM[[cc]yy][.SS] date [-u] [+format] date -a [-]sss[.fff] which analysis fit the best for the data? I am trying to work on the data of my master thesis. I have to create a model, but I don't know which analysis perform. My data look like this     number ID sp ab alt SWdiv     1 A1 4 6 630 0.25802965   2 A2 9 16 750 0.29235324   3 A3 8 14 850 0.411620203   4 A4 9 22 950 0.444079553   5 A5 2 12 1050 0.294855765   6 A6 13 40 1130 0.298451014   7 B1 2 2 750 0.275329152   8 B2 5 6 850 0.043352118   9 B3 14 16 950 0   10 B4 17 58 1050 0.230358688   11 B5 7 9 1150 0.298759725   12 B6 8 68 1250 0.012192474   13 C1 12 20 830 0.467542842   14 C2 13 19 930 0.454480722   15 C3 6 30 1030 0.464584038   16 C4 7 14 1130 0.448191833   17 C5 5 15 1250 0.052045275   18 C6 2 7 1315 0.051767368   19 D1 3 3 650 0.294855541   20 D2 11 17 750 0.291717599   21 D3 9 46 850 0.084284864   22 D4 8 57 950 0.088574421   23 D5 4 32 1050 0.160873283   24 D6 13 22 1150 0.297638962   25 D7 6 22 1250 0.290733158   26 E1 11 23 800 0.250878932   27 E2 8 8 900 0.418021272   28 E3 10 13 1000 0.132159303   29 E4 5 10 1100 0.058487554   30 E5 5 15 1200 0.250310822   31 E6 10 19 1350 0.01600807   32 F1 6 20 800 0.462497319   33 F2 15 54 900 0.376552904   34 F3 6 13 1000 0.298264791   35 F4 6 13 1100 0.394736812   36 G1 14 22 830 0.391455956   37 G2 11 16 930 0.282922551   38 G3 5 10 1030 0.282398234   39 G4 10 15 1130 0.153502726   40 G5 13 18 1230 0.051586706   41 H1 10 11 700 0.3009609   42 H2 7 14 800 0.579228102   43 H3 5 11 900 0.528108703   44 H4 20 48 1000 0.28689587   45 H5 13 18 1100 0.264542772   46 H6 10 20 1250 0.29928462   47 I1 12 13 535 0.35326876   48 I2 3 5 635 0.273947657   49 I3 18 30 720 0.467208221   50 I4 16 188 835 0.276669711   51 I5 7 69 935 0.000867067   52 L1 6 10 435 0.36910895   53 L2 7 20 606 0.236700524   54 L3 14 33 697 0.111132519   55 L4 17 42 797 0.296757045   56 L5 5 7 910 0.27539552   57 L6 10 15 1000 0.29748451   58 L7 6 11 1101 0.276755556     58 sample points each has two value: altitude and diversity index related to habitat heterogeneity. What I sample are different insects and I have two values: sp = species (total number of different species for each sample point) and ab = abundance (total number of insects for each sample point). My question are are the species richness or the abundance affected by the altitude or the habitat heterogeneity? which is the best analysis to perform? and why? thank you for your help. What is the result of $ \lim_{n \to \infty} \frac{ \sum^n_{i=1} i^k}{n^{k+1}},\ k \in \mathbb{R} $ and why? On the  blog post, nearly all the images are broken. I assume this is because they are all hosted on stackoverflow.blog/wp-content/uploads/ rather than zgab33vy595fw5zq-zippykid.netdna-ssl.com/wp-content/uploads/, and they got destroyed in the removal of Blog Overflow. I looked around at a few other blog posts, and this post seems to be the only one having an issue. TestMethod do not support Web service callouts, test skipped I want to run Notepad++ twice. Like in this paint printscreen.  How I want it:    Not what I want:    Is this possible? How do you safely encode a URL using JavaScript such that it can be put into a GET string?  var myUrl = "http://example.com/index.html?param=1&amp;anotherParam=2"; var myOtherUrl = "http://example.com/index.html?url=" + myUrl;   I assume that you need to encode the myUrl variable on that second line? How to fill a rectangular hole with an even amount of vertices on either side? I tried crating faces but it left missing edges. In the end I was left with all the right lines but there was no vertex in the center.    Here's a follow up image in case you're wondering what I mean. Notice how there's no vertex in the center. losing ligatures when switching font series or color in the middle of a word Is it good English to say "They have just left", when talking about a single person (perhaps someone you don't know the gender of)?  (I am a native English speaker, I'm looking for the view held by lexicographers). I am trying to use the  package.  I have the following counters defined (hopefully this is the right way to do it!)  \newtheorem{thm}{Theorem}[section] \newtheorem{lemma}[thm]{Lemma} \newtheorem{cor}[thm]{Corollary}   This works as I would like (i.e. Theorem 1.1, Corollary 1.2, Lemma 1.3, etc.)  My problem is \cref always returns Theorem 1.2, Theorem 1.3. I   Perhaps this is not right? (In my preamble)  \crefname{thm}{theorem}{theorem's} \crefname{lemma}{lemma}{lemma's} Permission denied, are you root? I get this error whenever I try to install programs using the terminal:  home@ubuntu:~$ apt-get install myunity E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?   Also I'm unable to install updates using the terminal. I've seen papers (e.g., in Science) where the first two authors are listed in non-alphabetical order, and yet there are asterisks behind their names to say that they contributed equally.   It seems strange to me, because if the two authors are in alphabetical order, then it could be that the first author contributed more or the two contributed equally, and this can be made clear with asterisks in the paper if it's the latter case. When they're in non-alphabetical order, however, if someone only sees the author list without seeing the paper, he/she will likely assume that the first author contributed most.  So my question is: Are there particular reasons why people do that? (This  is related, but I don't think the answers there get to my question.) Creating Two Executable Jars Using maven-assembly-plugin The Node Editor won't work for the object selected I'm still learning, but I'm trying to follow a tutorial to apply texture to a model. I only want to apply the texture to one object in the scene, so I selected it, unwrapped it, and painted over it. Now I selected it in the Edit Mode (I can't select it in the Object mode because all is locked together) and went into Node Editor, but the nodes are greyed out.  Why? "any other verbs then being located in VP" -- is this acceptable? if the sentence you are analysing contains a modal verb, then it is positioned in ‘I’,any other verbs then being located in VP.      (English Syntax and Argumentation - Bas Aarts)   At first, I think the The bold clause should be "...is located..." but then I realize it might be in the form of a non-finite clause (ing clause with a subject) but I'm not sure. If it isn't, how you describe this usage? Is this common in English? no wifi in Ubuntu 15.04 I cannot see WiFi option in my Ubuntu 15.04. What should I do? Revert asap  lspci -nnk | grep 0280 -A2 output:-  03:00.0 Network controller [0280]: Qualcomm Atheros Device [168c:0042] (rev 30) Subsystem: Foxconn International, Inc. Device [105b:e09a]   rfkill list output:-  0: hci0: Bluetooth Soft blocked: no Hard blocked: no 1: acer-wireless: Wireless LAN Soft blocked: no Hard blocked: no      dmesg | grep ath [    9.545199] ath10k_pci 0000:03:00.0: pci irq msi-x interrupts 8 irq_mode 0 reset_mode 0 [   10.029684] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/cal-pci-0000:03:00.0.bin failed with error -2 [   10.029701] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-5.bin failed with error -2 [   10.029704] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-5.bin': -2 [   10.029711] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-4.bin failed with error -2 [   10.029713] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-4.bin': -2 [   10.029719] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-3.bin failed with error -2 [   10.029721] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-3.bin': -2 [   10.029726] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware-2.bin failed with error -2 [   10.029728] ath10k_pci 0000:03:00.0: could not fetch firmware file 'ath10k/QCA9377/hw1.0/firmware-2.bin': -2 [   10.029733] ath10k_pci 0000:03:00.0: Direct firmware load for ath10k/QCA9377/hw1.0/firmware.bin failed with error -2 [   10.029735] ath10k_pci 0000:03:00.0: could not fetch firmware (-2) [   10.029737] ath10k_pci 0000:03:00.0: could not fetch firmware files (-2) [   10.029739] ath10k_pci 0000:03:00.0: could not probe fw (-2) How to show that $\mathbb{Q}$ is not $G_\delta$ I read a section of a book and it made mention of the set of rationals not being a $G_\delta$. However, it gave no proof. I read on  about using contradiction, but it made use of the Baire category theorem, which is unfamiliar to me. I was wondering if anyone could offer me a different proof; perhaps using the fact that the complement of $G_\delta$ is $F_\sigma$.  Thanks. How to remove the lines which appear on file B from another file A?