Will this power supply damage my gear?
Choosing power supply, how to get the voltage and current ratings?
Right identity and Right inverse implies a group Let $(G, *)$ be a semi-group. Suppose   $ \exists e \in G$ such that $\forall a \in G,\  ae = a$;  $\forall a \in G, \exists a^{-1} \in G$ such that $aa^{-1} = e$.    How can we prove that $(G,*)$ is a group? Initializing K-means centers by the means of random subsamples of the dataset? If I have a certain dataset, how smart would it be to initialize cluster centers using means of random samples of that dataset?  For example, suppose I want 5 clusters. I take 5 random samples of say, size=20% of the original dataset. Could I then take the mean of each of these 5 random samples and use those means as my 5 initial cluster centers? I don't know where I read this but I wanted to know what you guys think about the idea.    UPDATE: Please see this thread  for the general discussion about the various initialization methods. Suppose we have a set of primes $p_1,\dots,p_t$. Prove that  $\log p_1,\dots,\log p_t$ is linear independent over $\mathbb{Q}$. Now, this implies $ \sum_{j=1}^{t}x_j\log(p_j)=0 \iff x_1=\dots=x_t=0$.  I think I have to use that fact that every $q\in\mathbb{Q}$ can be written as $\prod_{\mathcal{P}}$, where $n_p$ is a unique sequence ($n_2$,$n_3$,$\dots$) with domain $\mathbb{Z}$. Here, $\mathcal{P}$ denotes the set of all integers.  Now how can I use this to prove the linear independency? Changing order of features in shapefile How to disable touchscreen permanently on ubuntu 18.04 How do you select a particular option in a SELECT element in jQuery? What are Ctools plugin (content type, access, etc), and how does one create them? What are Ctools plugins, and how does one create them? List files sorted by the number of lines they contain How can I list the number of lines in the files in /group/book/four/word, sorted by the number of lines they contain?   ls -l command lists them down but does not sort them Castellation metal loop connector Problems after upgrading to 14.04 (only background and pointer after login) I have 2 partitions (Windows and Ubuntu 13.04) and I am asked which one to boot each time I turn on my computer.  I want to install Ubuntu 13.10 to the entire disk.  I do not mind if all previous Ubuntu/Win data are lost.  How can I do that? When a divination wizard character uses their Portent ability:     Starting at 2nd level when you choose this school, glimpses of the   future begin to press in on your awareness. When you finish a long   rest, roll two d20s and record the numbers rolled. You can replace any   attack roll, saving throw, or ability check made by you or a creature   that you can see with one of these foretelling rolls. You must choose   to do so before the roll, and you can replace a roll in this way only   once per turn.   ... to replace a roll, can a player with the Lucky Feat:     Whenever you make an attack roll. an ability check, or a saving throw,   you can spend one luck point to roll an additional d20. You can choose   to spend one of your luck points after you roll the die, but before   the outcome is determined. You choose which of the d20s is used for   the attack roll, ability check, or saving throw.      You can also spend one luck point when an attack roll is made against   you. Roll a d20, and then choose whether the attack uses the attackers   roll or yours.      If more than one creature spends a luck point to influence the outcome   of a roll, the points cancel each other out; no additional dice are   rolled.   ... use the Luck Roll to replace the result? Or does the Portent trump all rolls and simply give you the final outcome?  This question spun off from  on .  Some relevant points:  .  Mike Mearls tends to believe that luck can triumph in some cases, but admits this is , and further seems to conflate the question with .  I would suggest reading the linked discussion before formulating an answer. There's some good thought there. Display lines in last 10 minutes with specific pattern in logs I need to display lines with Error occurred in last 10 minutes of a log file.   Aug 26 10:50:42 Normal line. Aug 26 10:51:23 Normal line. Aug 26 10:55:33 Error line. Aug 26 10:56:45 Normal line. Aug 26 10:58:12 Error line. Aug 26 11:02:31 Normal line. Aug 26 11:03:32 Normal line. Aug 26 11:04:11 Normal line.   Suppose above sample of log file. I want to display only following two lines  Aug 26 10:55:33 Error line. Aug 26 10:58:12 Error line.   I am using AIX. What's the fastest connection speed / shortest elapsed time using Migration Assistant? When using Migration Assistant to move users, files, and folders from an old Mac to a new one, you have a few different choices, depending on the Macs involved. Presuming that both Macs have appropriate ports, which ports should be used in a real-world situation? Please do not provide quotations of theoretical port speeds; I'm looking for real-world experiences as to what will get the job done faster.  Port choices:   FireWire 400 in target disk mode FireWire 400 to 800 in target disk mode FireWire 800 in target disk mode 100 Megabit Ethernet to Gigabit Ethernet in the OS Gigabit Ethernet to Gigabit Ethernet in the OS Thunderbolt cable in target disk mode Why does my item name not show up in 1.13? I understand that you can (in principle) measure whether "free particles" (no forces) experience accelerations in order to tell whether a frame is inertial. But fundamentally, what determines which frames are inertial (i.e. what principle selects in which frames free particles will not appear to accelerate)? I've been told that the cosmic microwaves determine the ultimate rest frame of the universe, but that doesn't make sense to me, since one can still ask why that frame is an inertial frame.  Also, I understand that there are no real inertial frames in general relativity, but it seems like there certainly exists approximate inertial frames and we can ask why those frames are approximately inertial and not others. For example, in the frame of a person riding a merry go round, free particles appear to greatly accelerate; while in the frame of someone standing next to the merry go round there are no such great accelerations. Why does the guy (or gal) on the merry go round see free particles accelerating while the other guy doesn't.   And if you're gonna tell me that it's "the rest of the stuff in the universe" that determines whether the person on the merry go round sees free particles accelerate, I'll ask how you know that all that stuff is not spinning.  I hope this question sort of makes sense, it's been bothering me for a while and my study of relativity (most of special relativity and just the outline of general relativity) hasn't really clarified it for me much. Why does $(\frac{p-1}{2}!)^2 = (-1)^{\frac{p+1}{2}}$ mod $p$? Assume $p$ is prime and $p\ge 3$.  Through experimentation, I can see that it's probably true. Using Wilson's theorem and Fermat's little theorem, it's equivalent to saying $2^2 4^2 6^2 \cdots (p-1)^2 = (-1)^{\frac{p+1}{2}}$ mod $p$, but I can't figure out any more than that. What happens to folks who get question banned, by and large? There is a steady stream of duplicates of  coming in lately. It's got me wondering. Roughly speaking, out of say 100 folks who get this ban, how many    wander away and never interact with SO again?   do the sorts of things that might lift a ban, but don't get it lifted? do the sorts of things they should, and lift the ban? post a question of their own on Meta which we close as a dupe?   Among the continue-to-interact folks, is there a difference in success rate between those who post on Meta about it (motivated, but not good rules-readers, who nonetheless get customized advice) and those who do not (better rules readers, but working to some extent blind) - which do better?  Is there a reasonable chance of recovering from a ban, assuming you care enough to try? Example of a finitely generated module with submodules that are not finitely generated Prove $0! = 1$ from first principles How can I prove  from first principles that $0!$ is equal to $1$?