Separable $\Rightarrow$ Lindelöf for metric spaces without using second-countability
Does proving (second countable) $\Rightarrow$ (Lindelöf) require the axiom of choice?
Where can I send feature requests? Show that    $$\frac{\sum_{i=0}^n\binom{k}{i}\binom{M-k}{n-i}\frac{k-i}{M-n}}{\binom{M}{n}}=\frac{k}{M},$$ where $M-k&gt;n$ and $k&gt;n$   From Vandermonde's identity, I get $\sum_{i=0}^n\binom{k}{i}\binom{M-k}{n-i}=\binom{M}{n}$.   But what about the sum of the product in the numerator? Any hint will be helpful. Java generics T vs Object Why didn't Kenobi start training Luke earlier? When Anakin was only 9 years old, everyone in the Jedi Council was arguing that he was already too old for Jedi training.  When it comes to Luke, it was a pre-planned agenda to make him a powerful Jedi. So, why did Kenobi wait for Luke to be much older? He could have started Luke's training by himself. Story about a future with races Compare 2 files and remove any lines in file2 when they match values found in file1 How do I sudo a command in a script without being asked for a password? I want to turn my system on automatically every day. So I use the below code in my Python script, but sudo asks me for a password every time:  os.system('sudo sh -c "echo date \'+%s\' -d \'+ \        24 hours\' &gt; /sys/class/rtc/rtc0/wakealarm"')   How can I run this script without sudo asking for the password every time? Convergence of $A_nT$ to $AT$ in operator norm for compact $T$ $A_n:Y\rightarrow Z$ are operators that strongly converge to $A$. Also, $\|A_n\|_\text {op}\le c$ for $c&gt;0$. Given a compact operator $T:X\rightarrow Y$, I need to show that $A_nT$ converges to $AT$ in operator norm (all spaces in this question are Banach spaces).     I was unable to prove this and I also do not understand why we need to assume that $T$ is compact. Any ideas? I'm looking for a way to insert a &lt;style&gt; tag into an HTML page with JavaScript.  The best way I found so far:  var divNode = document.createElement("div"); divNode.innerHTML = "&lt;br&gt;&lt;style&gt;h1 { background: red; }&lt;/style&gt;"; document.body.appendChild(divNode);   This works in Firefox, Opera and Internet Explorer but not in Google Chrome. Also it's a bit ugly with the &lt;br&gt; in front for IE.  Does anyone know of a way to create a &lt;style&gt; tag that   Is nicer Works with Chrome?   Or maybe   This is a non-standard thing I should avoid Three working browsers are great and who uses Chrome anyway? 101 positive integers placed on a circle A Pigeonhole Principle problem:     101 positive integers are placed on a circle whose sum is 300. Prove   that it is possible to choose from these numbers some consecutive   numbers whose sum is equal to 200.   (I don't know if the word 'consecutive' is appropriate in this case ,I mean that these numbers follow each other on that circle) Does anyone know how prove the following?   Suppose that $f,g$ are holomorphic functions on a non-empty open connected set $\Omega \subset \mathbb{C}$ and that $|f|^2+ |g|^2$ is constant on $\Omega$. Show that $f$ and $g$ are constant on $\Omega$. How to make the term "page" show in the Glossary list? I am trying to master the homemade Neapolitan pizza, from dough preparation to cooking it.  After following the recommendations at Seriouseats.com for the dough preparation, I came across some doubts regarding the oven use.  I understand that ideally I would make it in a 900F wood oven, but at home we don't have such equipment!  What is the best practice to make the Neapolitan Pizza in a regular gas oven that heats up to 530F? (i.e. temperature, time, tray positioning...) Are there changes in the way the dough has to be prepared? How can I detect if I'm in a subshell? How do I identify predatory and low quality journals? With Beall's List gone, how can I tell if a journal is spam? . While the reasons for his doing this are not yet public, this is a real loss of a valuable service. Does anyone know of similar services available to the general public?  Edit:  is definitely relevant, but that approach is more appropriate for finding top journals rather than identifying bottom ones. I.e., following that method would probably exclude lots of valid, lower-tier journals. Are there any approaches to easily identifying a predatory publisher? Zombie process using 100% CPU A zombie process, which should not be using any resources (RAM and CPU), is hogging up an entire core on my 8-core 64-bit Ubuntu 11.10 Desktop installation.  This is the output of ps -el|grep Z:  F S   UID   PID  PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD 0 Z  1000 10317     1 99  80   0 -     0 exit   ?        19:27:15 java &lt;defunct&gt;   ... and here is an excerpt from top:    PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                                                                                                 10317 deltik    20   0     0    0    0 Z  100  0.0   1170:17 java &lt;defunct&gt;  1424 root      20   0  612m 193m 158m S   14  2.4 287:17.11 Xorg 12580 deltik    20   0  710m 135m  46m S    5  1.7  27:31.07 compiz   This is how the zombie process came to existence:   I opened a Java JAR called . This launcher downloads another JAR file to ~/.minecraft/bin/minecraft.jar That JAR was executing when I locked my computer with xscreensaver. Then, I entered my password to unlock the computer, and I saw that the Minecraft window was frozen. I tried killing it (PID 10317) with gnome-system-monitor. It became a zombie. kill -9 10317 was ineffective. xkill only closed the window titled "Minecraft"; it didn't close the underlying java process.   Relevant information:   The graphics driver is FGLRX, and it has caused notorious issues with  of  and , including sometimes high CPU usage of Xorg and compiz.   I want to know:   What way is there to destroy this process of java without restarting, if any? Why is this issue happening? What can I do to prevent this issue from happening again? I want to play a game in an older update, but can't see a way to choose a specific version. Is this possible? How can I flush the output of the print function? How do I force Python's print function to output to the screen? In episode 10 of Full Metal Alchemist: Brotherhood, during the events in the Research Lab 5, Edward Elric is severely hurt. Later in the hospital, he writes down everything he had come to know, and he discusses with Alphonse, Hughes, and Armstrong about what to do with the information to continue the investigation.  At this point, King Bradley arrives with lemon into the room. He finds out what they are doing but acts very calm and chilled out and allows them to continue investigation while being careful.  Why did he not get Hughes and Armstrong killed at that point? Or at least tell them to not investigate at all? Upon answering the telephone, the person calling asks if Joan is available. If Joan is the person who answered the phone, should she say "This is her" or "This is she"?