W, A, S, D, keys and shift aren't working together
How do I remove the limit on PC keyboard button presses?
What is the best regular expression to check if a string is a valid URL? Play YouTube videos with MPMoviePlayerController instead of UIWebView $X$ is a Hausdorff space and $\sim$ is an equivalence relation.  If the quotient map is open, then $X/{\sim}$ is a Hausdorff space if and only if $\sim$ is a closed subset of the product space $X \times X$.  Necessity is obvious, but I don't know how to prove the other side. That is, $\sim$ is a closed subset of the product space $X \times X$ $\Rightarrow$ $X/{\sim}$ is a Hausdorff space. Any advices and comments will be appreciated. I just installed a new version of Ubuntu and I want to roll it back to the previous version.  How can I do that? Is that even possible? How can I play around targeted discard? Many decks in competitive Magic have access to targeted discard spells, like  and .  Against counterspells, you can rely on a variety of tricks like baiting counters, bottlenecking your opponent's mana, and good old-fashioned counter wars. Targeted discard cards allow your opponent to attack your hand on the very first turn of the game, and go right for your key cards &mdash; and it can often be backbreaking when your opponent takes away a crucial card like a combo piece or a sweeper.  What tricks and tactics can you employ, either during deck-building or in play, to play around an opponent's targeted discard?  (I know that one of the answers is going to be . That's excellent, but please also include approaches that work in formats without free countermagic.) I have installed Ubuntu Server on an old desktop, and I'm new to this.  I had set it up and was trying to connect through Putty but that was not working.  When I tried ifconfig there was no eth0 IP address, and logging onto the router showed the only device connected by ethernet is the printer.  However, the ethernet cable is plugged into the server and is showing the green light by it.  I tried opening /etc/networking/interfaces but this shows the following:  source /etc/network/interfaces.d/*  # The loopback network interface auto lo iface lo inet loopback   I tried adding 'auto eth0' after this and saving but made no difference, and have tried sudo ifconfig eth0 up which didn't do anything either.  sudo lshw -C network says that the network is DISABLED.  Any ideas to help get this up and running?  EDIT: Running command lspci -knn | grep Eth -A3 results in the following:  02:05.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL-8110SC/8169SC Gigabit Ethernet [10ec:8167] (rev 10)          Subsytem: Gigabyte Technology Co., Ltd GA-MA69G-S3H Motherboard [1458:e000]          Kernel driver in use: r8169          Kernel modules: r8169 An inequality from Littlewood's Miscellany combine 2 fields in 1 to use it in the "group by" section of the reports is it possible to combine two fields in one and use that field to group by in reports? for example, i would like to combine ee id and ee name fields in 1 and show as 1 field in the "group by" section on reports. I'm struggling a bit with functions(limits, squeeze theorem, etc).  I have done some research and found a list of books on calculus but I'm not sure which one would be better suited for me, so I would appreciate if some experienced people here could advise me which books would be better to master the basics so I can move on with derivatives, etc. Limits is my main problem, so I need a book which explain this in depth so I can master it. Then I'll keep going on with the same book for other chapters.  Below is the list which I found :   Apostol T.M. Calculus Vol. 1 Burn R.P. Numbers and Functions: Steps into Analysis  Courant R. and John F. Introduction to Calculus and Analysis I - One of the better calculus text in print.  Crowell B. Calculus  Dawkins, P Calculus I and Calculus II  Garrett P. Calculus  Ghorpade S.R. and Limaye B.V. A Course in Calculus and Real Analysis  Gill G.S. Calculus Bible  Guichard D. Whitman Calculu.  Hardy G.H. A Course of Pure Mathematics  Hwang A.D. Calculus for Mathematicians, Computer Scientists, and Physicists: An Introduction to Abstract Mathematics  Santos D. Differential Calculus  Shapiro B.E. Calculus and Analysis  Spivak M. Calculus  Strang G. Calculus  Thomas G.B. and Finney R.L. Calculus and Analytic Geometry  Tranter C.J. Advanced Level Pure Mathematics  Tranter C.J. Techniques of Mathematical Analysis  Veeh J.A. Lectures Notes on Calculus  So far I narrowed my list down to Hardy, Spivak and Apostol based on further research, but I haven't got my hands on these books yet to compare them and I'm not sure if these books will be good for me.  Thanks. Linear functional on a Banach space is discontinuous then its nullspace is dense. What ubuntu applications provide support? (guides, how to's, status) Also, specifically, details on support for syncing music to iPhone's and iPod's with the latest OS version:   Can you sync music to apple devices using >iOS4? (iPhone &amp; iPod) What applications allow you to do this and how? (guides, how to's, status)    What has already been established is:   Apple does not support Linux and has no plans to.  provides some support, however it currently does not support music/video synchronization with devices &gt;iOS4. Go to  and scroll to the section titled "" to see if your device version is supported. Can't launch graphical apps from terminal after updating to 15.10 How to choose input method on Kubuntu 18.04? Is it somehow possible that I can extend the link to something which I produce by using \ref with a label by the word standing before \ref? If I write something like that: For further information, have a look into chapter \ref{chap:abc} and figure \ref{fig:def}  then the only thing being &quot;clickable&quot; are the chapter number and the figure number. Is it somehow possible to make the words &quot;chapter&quot; and &quot;figure&quot; being linked to those objects as well? I am fairly new to blender and I am trying to do something which I am assuming is fairly straight forward with no success. All I'm looking to do is emboss some text onto the curved part of a yogurt pot. Image attached below. What is the quickest and easiest way of doing this?  Thanks in advance Let $p(t) =  a_0+\dots +a_nt^n, a_n\neq 0,$ a polynomial with degree $n&gt;0$. Prove that $p:\mathbb{R}\rightarrow \mathbb{R}$ is not bounded, but for any bounded subset $X\subset \mathbb{R}$ the restriction $p\vert X$ is bounded.   I want to prove this in very elementary terms. I mean, without using the notion of limit or even continuity. I can only show this with "strong" results. Is it possible with elementary terms? How can I play encrypted DVD movies? My machine can't play encrypted DVDs on a fresh install.  How do I add this capability?  Another useful bit of information would be what programs are best for playing DVDs, once I'm able to do so.  See the .  Will I be able to play DVD movies from ? Interface naming in Java Most OO languages prefix their interface names with a capital I, why does Java not do this?  What was the rationale for not following this convention?  To demonstrate what I mean, if I wanted to have a User interface and a User implementation I'd have two choices in Java:        Class = User, Interface = UserInterface   Class = UserImpl, Interface = User      Where in most languages:     Class = User, Interface = IUser   Now, you might argue that you could always pick a most descriptive name for the user implementation and the problem goes away, but Java's pushing a POJO approach to things and   most IOC containers use DynamicProxies extensively.  These two things together mean that you'll have lots of interfaces with a single POJO implementation.  So, I guess my question boils down to: "Is it worth following the broader Interface naming convention especially in light of where Java Frameworks seem to be heading?" What order should Asimov's Foundation series be read in? Why didn't Thanos come to Earth to retrieve Tesseract by himself? In the Avengers movie, why didn't Thanos personally come to Earth instead of Loki? Or, if Loki's skills were required, why didn't he come with Chitauri? He knew that humans were primitive; there wouldn't be any threat and he could personally secure Tesseract.  AFAIK, the movie didn't display much. Is there any other source answering this?