pythonic way to delete elements from a numpy array
How to remove specific elements in a numpy array
Infinite sum of ideals I've been trying to prove that given a ring $R$ and a collection of ideals $\{I_{\beta}\}_{\beta \in B}$ in $R$, the set $$\sum_{\beta \in B} I_{\beta}=\{f_1+\cdots+f_r:f_j \in I_{\beta_j}, \mbox{ for some } I_{\beta_j}\}$$ is an ideal and is the smallest ideal containing $\cup_{\beta \in B} I_{\beta}$.  I've already proved when I only have two ideals, and so, using induction, I've seen it for finite sums. But I don't see how to generalise that to an arbitrary family of indexes (maybe infinite) $\beta$.   Could someone please give me a hand? Thank you. self referential struct definition? I haven't been writing C for very long, and so I'm not sure about how I should go about doing these sorts of recursive things... I would like each cell to contain another cell, but I get an error along the lines of "field 'child' has incomplete type". What's up?  typedef struct Cell {   int isParent;   Cell child; } Cell; My neighbor has asked me help with his laptop, an HP with lost power-on password. I tried inserting an Ubuntu cd to format the partition, but well... it doesn't even get there. Any ideas? Cannot find Underground Jungle Temple On my 1.2 Terraria Map I have been mining from left to right in my large underground jungle using my rocket launcher. Despite this, I have had no luck on finding the Underground Jungle Lihzahrd Temple. I have been searching the layer above where lava constantly spawns. Have I simply spawned in a world without one or am I searching in the wrong place? I have also considered using the clentimator with Dark Blue ammo to provide light, should I do that? Microsoft Exchange 2013 is not receiving internet email Protagonist becomes the avatar of an alien deity and has to cope with adversary god Split comma-separated strings in a column into separate rows "To which", "by which", "on which" etc I have come across the phrases like "to which","for which", "by which", "on which" and so on(using a preposition with a relative pronoun).   e.g. The chair on which the body was found..  Could someone please explain if there's a particular rule to be followed when building/using them?   Can I use any preposition before 'which'?  What if I say "The chair which the body was found on"? How would I decide which preposition to be put? Can I use other relative pronouns too?  Thanks in advance. How long typically are paper reviews? Is there such a thing as “too long”? When you review papers submitted for publication, is there an “optimal” length for reviews? In my experience as an author and referee, I have seen a large range of review lengths (for reference, a paper in my field is typically between 3 and 8 printed pages):   Zero length: for some of the papers I have authored, the reviewer just clicked the “accept as is” or “reject” checkmark on the review sheet, without adding any comment (at least, not any comment visible to me). It's not so common, but it has happened. Short length: a lot of time, I received reviews who consisted of a single paragraph. Medium: one full page, maybe two pages.   Although I have never received any such long reviews, I have myself written on a few occasions reviews that exceed two pages, including once or twice a four or five-page review.  These were cases where the paper was good, but could be (in my view) much improved and some of the aspects/consequences had escaped the authors' consideration.  I am wondering how useful reviews of various length are to editors. I often consider that “unmotivated” reviews are useless, as they do not give any real insight about the paper to the editor. For example, if the editor gets two conflicting non motivated reviews, how is she to decide?  On the other hand, although I write some from time to time, I have never received long reviews, so… is this something frowned upon? Recently I noticed that many people post .htaccess files here with:  &lt;IfModule mod_rewrite.c&gt;   Sometimes this even appears several times in the file! It obviously checks to see if mod_write is in fact enabled but the statements it protects are necesary to those sites anyway. So if the IfModule fails, the website is broken anyway.  Is there an advantage in having the &lt;IfModule mod_rewrite.c&gt; fail rather than the RewriteRule statements below it?  mod_write now is so essential and ubiquitous that I do not check for it anymore. Might this cause a vulnerability of some kind? Say I am logged into a remote system, how can I know what it's running? On most modern Linuxes (Linuces?), you have the lsb_release command:  $ lsb_release -ic     Distributor ID: LinuxMint Codename:       debian   Which as far as I can tell just gives the same info as /etc/lsb-release. What if that file is not present? I seem to recall that the lsb_release command is relatively new so what if I have to get the OS of an older system?  In any case, lsb stands for Linux Standard Base so I am assuming it won't work on non-Linux Unices. As far as I know, there is no way of getting this information from uname so how can I get this on systems that do not use lsb_release? Who are the clients of my shared iTunes library? Is it possible to see who is currently connected and listening to a shared iTunes library? Is it possible to see which songs they listen to and how many/often?  It's not really important; I'm just curious about it. Would be nice to know which colleagues love my music… Charging lead-acid batteries? I am looking for a injective cochain map $\psi: C^*\rightarrow D^*$ such that the map $\Psi^i$ from $C^i$ to $D^i$ is injective, but the map $\psi^*$ from  $H^i(C^*)$ to $H^i(D^*)$ is not injective for any $i\geq0$. When ever I hear the music to indicate the Mysterious Stranger has arrived, I can never find him. It is almost like he is not in the vault.  What is a good way to catch the Mysterious Stranger? Where does he usually show up? Why do the big nuts always remain at top? The Brazil-nut Effect Finding the number of analytic functions which vanish only on a given set. Let $S = \{0\}\cup \{\frac{1}{4n+7} : n =1,2\ldots\}$. How to find the number of analytic functions which vanish only on $S$?  Options are   a: $\infty$  b: $0$  c: $1$  d: $2$ Do multiple instances of the Extra Attack feature stack? The WotC article  creates the &quot;Favored Soul&quot; sorcerous origin, which grants the the sorcerer the Extra Attack feature at level 6. Say I made Favored Soul sorcerer go up to level 6, and then multiclassed into Ranger to get its Extra Attack at level 5. Would the two Extra Attack features stack so that I could get 3 or 4 attacks in a turn? How to scale a tikzpicture to \textwidth Event handler not working on dynamic content