Why can't we order Complex Numbers?
Total order on complex numbers
How do I delete a file whose name begins with "-" (hyphen a.k.a. dash or minus)? How do you remove a file whose filename begins with a dash (hyphen or minus) -?  I'm ssh'd into a remote OSX server and I have this file in my directory:  tohru:~ $ ls -l total 8 -rw-r--r--    1 me  staff  1352 Aug 18 14:33 --help ...   How in the world can I delete --help from a CLI?  This issue is something that I come across in different forms on occasion, these files are easy to create, but hard to get rid of.  I have tried using backslash  rm \-\-help   I have tried quotes  rm "--help"   How do I prevent the minus (dash or hyphen) character to be interpreted as an option? If an polynomial has a complex root, is it necessary that the conjugate of that root is also a root of the polynomial? I am not sure about this. Please comment on this. Significance of the second focus in elliptical orbits 1.In classical mechanics, using Newton's laws, the ellipticity of orbits is derived. It is also said that the center of mass is at one of the foci.   2.Each body will orbit the center of the mass of the system.  My question is : Are the assumptions in 1 and 2 correct?   Follow up question : Assuming the distance from the centre of the mass to each body remains the same, do we have two bodies orbiting the centre of the mass of the system in an elliptical or circular orbit?   Finally : With elliptical orbits, if the heavier mass is supposed to be in one of the foci, if there is any significance to second focus, what is it? Is it a Lagrange point by any chance or does it have some other mathematical property? Are research survey questions expected to be handled with close votes? Can't delete files or folders on partition I have an NTFS partition. The idea is I can use this for data on either Ubuntu Mate or Windows 10 dual boot. It worked fine when I first installed Mate, but recently I no longer have the delete option when I right-click on a file or folder. The delete key does nothing. I also can't paste into the partition (Paste greyed out). It's as if the whole partition is read-only. In Gparted, the partition is marked with a key. Does this mean anything? I'm not aware of having changed anything, however, Windows recently did a big update - have they hijacked my drive?  I've read related posts, but people speak of returned errors - I have no errors, just nothing happens. Also, suggested solutions seem far too technical for what must surely be a simple tick-a-box fix!  Please note - for me the Terminal is where I get off a train and Sudo sounds like a Japanese noodle dish. ;) GUI's preferred if possible! Thanks for your patient help! Why not use exceptions as regular flow of control? Seems that I just proved $2=4$. Solving $x^{x^{x^{.^{.^.}}}}=2\Rightarrow x^2=2\Rightarrow x=\sqrt 2$.  Solving $x^{x^{x^{.^{.^.}}}}=4\Rightarrow x^4=4\Rightarrow x=\sqrt 2$.  Therefore, $\sqrt 2^{\sqrt 2^{\sqrt 2^{.^{.^.}}}}=2$ and $\sqrt 2^{\sqrt 2^{\sqrt 2^{.^{.^.}}}}=4\Rightarrow\bf{2=4}$.  What's happening!? Differences in meaning when the verb tense changes (headlines) What is the difference between the examples below?  Generally, in a newspaper, news is based on past tense (things which have already happened).   Then why are headlines written in ways that says: He Kills (shouldn't it be: He Killed)?  For example:  Parliament passes bill vs. Parliament passed bill  Also  He kills his friend vs. He killed his friend  Please help. Custom pagebreak in align equation What graduation gown should a PhD-holder wear when later receiving a Master's in another field? We use unit length Quaternion to represent rotations. Following is a general rotation matrix obtained ${\begin{bmatrix}m_{00} &amp; m_{01}&amp;m_{02} \\ m_{10} &amp; m_{11}&amp;m_{12}\\  m_{20} &amp; m_{21}&amp;m_{22}\end{bmatrix}}_{3\times 3}\tag 1 $.   How do I accurately calculate quaternion $q = q_1i+q_2j+q_3k+q_4$for this matrix?Means   how can we write $q_i$s interms of given $m_{ij}$  accurately? How to clear the interpreter console? How can tagged PDFs be created that support Universal Accessibility and reflowing? How to create tagged PDF such that they will be:   good enough for PDF/UA "reflowable" on smaller screens and ebook readers   Any syntax &amp; any engine are of interest, but I'm most interested in using LaTeX with [Xe|pdf]latex engines. Microbot Alpha says "All of your minions are considered Microbots."  Does this mean while this card is in play, every single minion in play and in discard and in my hand are considered Microbots?   For every Microbot Fixer in play, does every single minion I have in play now get +1 because they are all microbots? If Microbot Archive is in play, does every single minion I have now cause me to draw a card when destroyed? If I play Microbot Reclaimer, can I shuffle any minions from my discard pile into my deck (by considering them all microbots)?   It looks like this link addresses the first item above:   And it looks like this link addresses the 3rd item, implying that minions in the discard are not minions because they are out of play: Can somebody help me with the execute commands in Minecraft? Recently, Minecraft had removed the /testfor command, which broke these sets of commands that I was trying to execute today.  /testfor @p[r=10] {SelectedItem:{id:"minecraft:feather",tag:{display:{Name:"Roc's Feather",Lore:[Jump higher using this feather.]}}}}`   Now normally, from Minecraft 1.13 onwards, the new /execute command would've been the replacement for the /testfor command, but as I soon found out, the command failed to detect my Roc's Feather and thus could not execute an /effect command that gave me a Jump Boost, for 1 second, at level 3.  I tried remaking my feather from scratch with this command here:  /give @p minecraft:feather{display:{Name:"{\"text\":\"Roc's Feather\",\"color\":\"light_purple\",\"bold\":true,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}",Lore:["{\"text\":\"Jump higher using this feather.\",\"bold\":false,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}"]}} 1   But the execute command I placed did not detect this type of uniqueness.  /execute if entity @p[distance=10,nbt={SelectedItem:{id:"minecraft:feather",Count:1b,tag:{display:{Name:"{\"text\":\"Roc's Feather\",\"color\":\"light_purple\",\"bold\":true,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}",Lore:["{\"text\":\"Jump higher using this feather.\",\"bold\":false,\"italic\":true,\"underlined\":false,\"strikethrough\":false,\"obfuscated\":false}"]}}}}] run effect give @s minecraft:jump_boost 1 3 true   Can somebody tell me what I'm doing wrong here because I cannot even tell what's the issue. How do I change font size on the DataGridView? how to make some border lines of a table thick and colored Does $1.0000000000\cdots 1$ with an infinite number of $0$ in it exist? Does $1.0000000000\cdots 1$ (with  an infinite number of  $0$ in it) exist? Changing subject and verb positions in statements and questions How to differentiate a given inner product (CSIR DEC(2018) Let $A$ be a $n \times n$  invertible  matrix.Define a function $F:\mathbb{R}^{n} \times \mathbb{R}^{n} \rightarrow \mathbb{R}$ by $F(x,y)=\langle Ax,y\rangle$. Let $DF(x,y)$ denotes the derivative of $F$ at $(x,y)$ which is a linear transformation from $\mathbb{R}^{n} \times \mathbb{R}^{n} \rightarrow \mathbb{R} $. Then      1) if $x\neq 0$,then  $DF(x,0)\neq 0$      2) if $y\neq 0$,then  $DF(0,y)\neq 0$      3)  if $(x,y)\neq (0,0)$,then $DF(x,y)\neq 0$      4) if $x=0 \; or \;y=0$,then $DF(x,y)= 0$   I don't even know how to start the solution and also how to take derivative in higher dimensions.  Please help!  Thank you.