Why this is true?$\exists x \in U, [P(x) \land Q(x)] \Leftrightarrow [(\exists x \in U, P(x)) \land (\exists x \in U, Q(x))]$
Mixing and Distributing Qualifiers ($\forall x$, $\exists x$)
I'm still a newbie with Linux but I'm trying to learn. I have two USBs, one is 4GB and has the ISO install of Ubuntu (I think it's called live, the one with maximum of 4GB of permanent storage) and got a 64gb usb to make a permanent full install on it. I installed it following  tutorial and everything looks fine (I had to create the EFI partition with the Terminal though) but it just won't boot, the live install boots without problems.   I'm using the school's computers which have the UEFI menu password protected so I can't access that and I won't have a laptop for like 3 weeks (main reason why I'm doing this). I tested it with a friend's laptop disabling the Secure boot but it still wouldn't boot. I also saw that some tutorials don't add the EFI partition so I tried without that one and still won't work. And I know it's not the 64GB usb not booting because I had a live install on it too before and it booted fine.  Please, I have been trying to make it work for two days now, any ideas? I can barely understand this stuff so if you could explain step by step that would be awesome. Help with creating a symbolic link I'm confused with how symbolic links work. I hope someone can guide me in the right direction.  I want to put a demo online from our software, which normally only runs locally on a Mac Mini. So I put all the files in the var/www from my Ubuntu 12.04 server installation.  There are a lot of hardcoded links in the software which point to /Applications/XAMPP/xamppfiles/htdocs/narrowcasting  Of course, I could change all these code on my html/php files in /var/www, but that would be quite annoying. I hope I can fix this by creating a symbolic link. For example, I have a directory called thumb in /var/www/thumb. The PHP code is trying to put an image in /Applications/XAMPP/xamppfiles/htdocs/narrowcasting/thumb.   Can anyone give me a tip how to achieve this with a symbolic link? How can I deduce/identify an app from a notification icon? Finitely generated projective module Variation on Vandermonde's identity How can you show that $$ \binom{2n}{n}^2 = \sum_{m=0}^{n} \binom{2n}{2m} \binom{2m}m \binom{2n-2m}{n-m} $$?  I was fooling around with random walks, and apparently both expressions are supposed to be the number of unweighted random walks on a 2D square lattice of $2n$ steps that ends at the origin.  Whole thing reminds me of Vandermonde's identity but I can't it. Any hints? Unable to preserve ownership in a copy but able with a move? What will I miss out on if I play Diablo 3 without Reaper of Souls? I own the base game of Diablo 3.  I didn't really like the "post-Inferno" content of the game, so I stopped playing shortly after I curb-stomped the final boss for the n-th time.    I understand now that a lot of things have changed in the base game.  There's also an expansion.  I don't plan to purchase the expansion, but some of these changes sound like they could make the game more fun for me.  I can guess that probably the new character and act are expansion-only content.  I know I'm probably , but if I go back and play now, what else will I be missing out on if I don't have the expansion? OpenSource ATI driver - Fan running at full speed all the time I know this is a common problem and have read other topics but couldn't resolve. Anyways yesterday I found a solution - I have 2 graphic cards (hybrid) and they were both on. So I turned one off and installed Jupiter for power management and from there on the fans were quiet and I was happy as hell.  However (:)), yesterday evening I also updated the system and the fan and it's noise came back. I checked whether I am using only 1 graphics card and I am.  c0dehunter@mintBox ~ $ sudo lshw -c video [sudo] password for c0dehunter:    *-display                       description: VGA compatible controller        product: RS780M/RS780MN [Mobility Radeon HD 3200 Graphics]        vendor: Hynix Semiconductor (Hyundai Electronics)        physical id: 5        bus info: pci@0000:01:05.0        version: 00        width: 32 bits        clock: 33MHz        capabilities: pm msi vga_controller bus_master cap_list rom        configuration: driver=radeon latency=0        resources: irq:18 memory:c0000000-cfffffff ioport:c000(size=256) memory:fbcf0000-fbcfffff memory:fbb00000-fbbfffff   Maybe the problem is (false) temp reading from GPU?  c0dehunter@mintBox ~ $ sensors acpitz-virtual-0 Adapter: Virtual device temp1:        +44.0°C  (crit = +105.0°C)  k10temp-pci-00c3 Adapter: PCI adapter temp1:        +47.0°C  (high = +70.0°C)                        (crit = +115.0°C, hyst = +110.0°C)  radeon-pci-0200 Adapter: PCI adapter temp1:       +127.5°C     The thing that is weird is that if I boot into Windows the fan is still at full power (previously it wasn't). Did I f--- up my hardware with software? :)  //OH, yes - I forgot to mention that my laptop is not hot at all. The temps are about 50°C. Zero divisor in $R[x]$ Let $R$ be commutative ring with no (nonzero) nilpotents. If $f(x) = a_0+a_1x+\cdots+a_nx^n$ is a zero divisor in $R[x]$, how do I show there's an element $b \ne 0$ in $R$ such that $ba_0=ba_1=\cdots=ba_n=0$? When to use "have" and "have got" How to manipulate a CSV file with sed or awk? How can I do the following to a CSV file using sed or awk?   Delete a column Duplicate a column Move a column   I have a big table with over 200 rows, and I'm not that familiar with sed. I would like to make a sum of all dropdown values into a label text box. I am using following formula, but I do not understand where am I going wrong. Can anyone assist? I have also added a screenshot if that helps anyhow. Note: scores is the table name the dropdown values feed from. Sum(scores, Dropdown3.Selected.Value + Dropdown3_1.Selected.Value + Dropdown3_2.Selected.Value) Java String array: is there a size of method? In plain English, how does casting spells and using creature abilities work with the stack and priority? I'm a relatively new player to Magic: the Gathering. I was reading  to try to understand exactly when it's okay to cast instants (e.g. ) and use some abilities (e.g.  should be tappable sometime during other peoples' turns), but I don't seem to be making much progress: as I come to understand some things, others make less sense.  My confusion is boundless  For instance: to cast  one needs priority. Spells go on the stack, and priority gets passed at some points (I have no idea when), and effects on the stack are resolved when both players have passed priority. But when is that? I can't find any mention of when the other player gets the priority to cast an instant, except on their own turn. Furthermore,  states that during the Main Phase:     505.4. Second, the active player gets priority. Players may cast spells and activate abilities. The active player may play a land.   So players (plural) may cast spells, but only the active player has priority, so only the active player can cast an instant. The turn rules, and the rules on , never mention any point at which the other player gets priority, so when can they possibly Cancel?  In addition, you can only cast a spell when the stack is empty, so the entire stack must be able to be resolved in your turn at some point.  I need an explanation!  I could go on a bit more. There is also  which can be overloaded to "Counter each spell you don't control", which seems like it could only possibly work with an understanding of the stack.  Could someone explain, in simple English:   When can Instants be cast? When can tap abilities be used? What do Instants and abilities have to do with the Stack and Priority? The latex file coding is not there but the pdf file is there I wrote all my coding in the .tex file. The next day when I opened it the coding is all gone and the pdf file is opening with it and is displayed as an output. How do I bring back my coding? What potions actually grant fame or glory, or put a stopper in death? Are there any? ‘You are here to learn the subtle science and exact art of potionmaking,’ [Snape] began. He spoke in barely more than a whisper, but they caught every word – like Professor McGonagall, Snape had the gift of keeping a class silent without effort. ‘As there is little foolish wand-waving here, many of you will hardly believe this is magic. I don’t expect you will really understand the beauty of the softly simmering cauldron with its shimmering fumes, the delicate power of liquids that creep through human veins, bewitching the mind, ensnaring the senses ... I can teach you how to bottle fame, brew glory, even stopper death – if you aren’t as big a bunch of dunderheads as I usually have to teach.’&#185;   Philosopher's Stone - page 102 - Bloomsbury - chapter 8, The Potions Master   Are there any canon potions that actually grant fame or glory, or stopper death? I'm looking for specific canon-based answers from sources such as the Harry Potter books, interviews with J.K. Rowling, or information from Pottermore. Maybe because it's early I'm overlooking the obvious, but offhand I can't think of any canon potions that fit this criteria exactly.   &#185;I edited in the entire paragraph that I can teach you how to bottle fame, brew glory, even stopper death comes from for clarity. Hopefully this will be helpful and provide a better context for the comment in question. Is it true that for algebraic sets $V,W$ we have $I(V \times W ) =I(V) + I(W)$? After installing fedora and Centos and other OS now I have them all showing in my Boot menu [F2] on start up not the menu form the OS even after deleting them and reinstaling other OS - Ubuntu -so It just shows one when the OS starts but when I go to UEFI setting I still find all the old ones they instruct you to use DEL to take them out but that does not work How to I stop a launchd script from running on wake I have a simple launchd script that plays a sound every 30 minutes and it runs out of the user library ~/Library . It doesn't run if my machine is asleep, but does run the last event missed when the machine wakes. I think this is the expected behavior. My question is, how do I stop this happening. If I missed the half-hour event, I don't want it to be run at 20 minutes past the hour.  Here's the core of my script. It calls a Python script. I tried to put a block in the python script to check that I am within a few minutes of each 30 minutes, but that doesn't seem to work on wake. (Is it missing the system clock somehow?)  &lt;key&gt;ProgramArguments&lt;/key&gt; &lt;array&gt;     &lt;string&gt;/usr/local/bin/python3&lt;/string&gt;     &lt;string&gt;/Users/pheon/Documents/playsound.py&lt;/string&gt; &lt;/array&gt;  &lt;key&gt;StartCalendarInterval&lt;/key&gt; &lt;array&gt;     &lt;dict&gt;         &lt;key&gt;Minute&lt;/key&gt;         &lt;integer&gt;0&lt;/integer&gt;     &lt;dict&gt;         &lt;key&gt;Minute&lt;/key&gt;         &lt;integer&gt;30&lt;/integer&gt;     &lt;/dict&gt; &lt;/array&gt;   Here is a snippet from the python code which checks the time before playing the sound.  time0 = datetime.datetime.now() if (time0.minute % 30) &lt; 2:     subprocess.run(["/Users/pheon/bin/afplay-vol.sh", "1", bell],check=True) If you are reading this, you may have been affected by one of our post quality bans. If so, it is important that you  to understand what has happened and how to regain the permissions that you lost. While trying to ask a question, one could see:  We are no longer accepting questions from this account. See  to learn more.  Likewise, for answers:  We are no longer accepting answers from this account. See  to learn more.   Why am I getting this message? Are deleted posts taken into account too? Is a question/answer ban the same as a suspension? How do I avoid getting a question ban? How long do I have to wait before I can post again? What can I do to release the ban? How can I reactivate my account? Can I simply create a new account? I'll just ask somewhere else on the SE network, and they'll migrate my question to the correct site! Will a ban on one Stack Exchange site affect my standing on other sites in the network? Does this apply to meta sites too? My account is in good standing. Why am I still blocked?