How can I solve this para Paradox?
Why $\sqrt{-1 \times -1} \neq \sqrt{-1}^2$?
How to rename file as below  AS1100801000002.RAW7AGS  AS1100801001008.RAW7AH4 AS1100801002001.RAW7AH9 AS1100801003002.RAW7AHE AS1100801004009.RAW7AHT AS1100801005002.RAW7AHY AS1100801010002.RAW7AJ3   to new name  AS1.txt AS2.txt AS3.txt AS4.txt AS5.txt AS6.txt AS7.txt I am installing Ubuntu 16.04 in an Intel NUC computer with UEFI enabled. I am using an SSD from another computer. During the installation I chose Erase the disk and make a new full install  At the end of the process I see:  grub-efi-amd64-signed failed installation /target/ Ubuntu 16.04    And the system does not boot.  I tried to use boot-repair but apparently it does not solve the problem. An operator has closed range if and only if the image of some closed subspace of finite codimension is closed. What is the difference between an Intel i7 and a Xeon quad core processor? I know the  processors have been around for a long time and are mostly used in servers, but I am curious, why do people not use the Xeons in a high performance desktop?    As far as I know about the best desktop processor out there now is the  line. The i7's and Xeons are both quad-core processors, what is the main difference in these? I just saw that the MacBook Pro's are using the quad core Xeons instead of the i7's. How do I delete one of two Ubuntus on my PC NOT IN vs NOT EXISTS If a group satisfies $x^3=1$ for all $x$, is it necessarily abelian? I know that any group satisfying $x^2=1$ for all $x$ is abelian. Is the same true if $x^3=1$? I don't think it is, but I can't find a basic counterexample. I'm trying to recall the name of a book I read, probably published after 1990, where alien AI infects satellites and a barrier is established, isolating earth from space that maybe slows down time inside of it, relative to the passage of time outside.  Mars or the moon is also colonized in an attempt to flee the now real possibility that the sun will become a red giant and wipe out humanity in the not-too-distant future (as perceived on earth), but the colony gets one of the time barriers as well.  I think the name of the novel was short, "The _______" (one word).  The story focused more on the human cost and followed one particular family, one member of which was somehow also partially infected by the alien AI, but I don't remember as much about them. Can I mention professors' names in the statement of purpose? For PhD applications, I have mentioned that I am interested in some research areas. Besides, I am thinking about mentioning some professors' names, so that it shows I have read their websites and I am not just sending out generic statements applicable to many schools.  But is it good to mention some professors' names in the statement of purpose, if I don't know them personally? In what cases is it good, and in what cases it isn't?  For example, is it good to only mention    those whose research directions are aligned with my research interests, or/and those whose books or notes I have heard of, or better, might have read some parts of, or/and those who are already established and famous (such as having certain titles), or/and those that are directing the PhD graduate programs, or/and those that are heads of the departments?    What will other professors who are not mentioned think? How will you do, if it were you? Partitions of $n$ into distinct odd and even parts proof To find the total no. of six digit numbers that can be formed having property that every succeeding digit is greater than preceding digit. I have a question and got strucked on this.. To find the total no. of six digit numbers that can be formed having property that every succeeding digit is greater than preceding digit. Please guide me to solve this. Thanks in advance. At the start of Harry Potter and the Philosopher's/Sorceror's Stone Voldemort's Killing Curse backfires      due to Lily's sacrifice protecting Harry from Voldemort.   leaving Harry with his scar      and a loose piece of Voldemort's soul   and Voldemort as a loose soul, self-described as "Less than a ghost".  Voldemort was not dead, but had no physical body (until he got better in book 4).  What happened to his body?  Did it disappear?  Or was it left in the rubble of the house, alongside the bodies of James and Lily? Given a Java InputStream, how can I determine the current offset in the stream? I'd like something like a generic, re-usable getPosition() method that will tell me the number of bytes read from the starting point of the stream.  Ideally, I would prefer this to work with all InputStreams, so that I don't have to wrap each and every one of them as I get them from disparate sources.  Does such a beast exist?  If not, can anyone recommend an existing implementation of a counting InputStream? Should I edit my deleted answer or add another answer? Choosing coordinate system to use in South Africa? What are the principal datums and projections used in South Africa including the names of geodetic datums and their projections? I get how a normal fork bomb works, but I don't really understand why the &amp; at the end of the common bash fork bomb is required and why these scripts behave differently:  :(){ (:) | (:) }; :   and   :(){ : | :&amp; }; :   The former causes a cpu usage spike before throwing me back to the login screen. The latter instead just causes my system to freeze up, forcing me to hard reboot. Why is that? Both continually create new processes, so why does the system behave differently?   Both of the scripts also behave differently from  :(){ : | : }; :   which doesn't cause any problems at all, even though I would have expected them to be alike. The bash manual page states that the commands in a pipeline are already executed in a subshell, so I'm led to believe that : | : should already suffice. I belive &amp; should just run the pipeline in a new subshell, but why does that change so much?  Edit: Using htop and limiting the amount of processes, I was able to see that the first variant creates an actual tree of processes, the second variant creates all the processes on the same level and the last variant doesn't seem to create any processes at all. This confuses me even more, but maybe it helps somehow? I am using scikit learn  to build a Random Forest classifier.  I have heard that it might be possible to build a single decision tree from a Random  Forest. The suggestion  is that although the decision tree may not be as good a classifier as the Random Forest it may be better than the decision tree you would get by using the standard method.  However I haven't been able to find this method online. Does it exist?     My question is not about extracting one  of the decision trees from a Random Forest. It is asking about a method to construct a new decision tree from the whole Random Forest, perhaps by combining the trees in the Random Forest somehow. Is there a way to run Python on Android? What does \s! do? Why didn't Umbridge succeed in Slytherin? The new information released about Umbridge on Pottermore on Halloween was interesting in that it demonstrated how insidiously Dolores Umbridge applied her ruthless ambition over the years. From making her half-blood family disappear from public view, to oozing her way through the Ministry and up the ladder of success, basically unfettered -- although no one liked her as a person, despite her saccharine demeanor -- this woman was over and again awarded significant positions of power where she could do tremendous damage to others.   Some might see these as Slytherin traits. Some. &lt; shifty eyes > So I was surprised to read that while Umbridge was a Slytherin student at Hogwarts, she was consistently overlooked for positions of power and prestige within Slytherin itself.   Why didn't Umbridge succeed in Slytherin?  RESOURCE: Pottermore on Dolores Umbridge:  ,