What are the parity of particles?
How is $J^{PC}$ value experimentally determined for new types of particles?
How can I restart an app game from the beginning Rationale behind pronunciation of "subtle" Let $R$ be a commutative ring with 1, we define  $$N(R):=\{ a\in R \mid  \exists k\in \mathbb{N}:a^k=0\}$$  and  $$U(R):=\{ a\in R \mid a\mbox{ is invertible} \}.$$  Could anyone help me prove that if $a\in N(R) \Rightarrow 1+a\in U(R)$?  I've been trying to construst a $b$ such that $ab=1$ rather than doing it by contradiction, as I don't see how you could go about doing that. What do you call a person who is never content with anything that is given to him? I am looking for an adjective for a person who, no matter what you give him/her (materially or otherwise), is never content and always expects more. How to fix soft 404 errors in GWT? In GWT I have been receiving soft 404 errors for some URLs of my online shopping website. Ichecked all those URLs and those pages are looking good and there is nothing wrong in that page. Then why I'm receiving that errors?  This is the notification that I received in my GWT:     Dear owner or webmaster,      While crawling your site, we have noticed an increase in the number of   transient soft 404 errors around 2013-06-30 16:00 UTC (London, Dublin,   Edinburgh). Your site may have experienced outages. These issues may   have been resolved. Unexpected workspace change? My friend who has only recently downloaded blender has come across a workspace issue. He said he accidentally pressed a button and it has entirely changed his user interface/ Workspace. He can't open, save or do anything with the change.    This is a full window image! Determine whether a number is prime How do I determine if a number is prime?  I'm writing a program where a user inputs any integer and from that the program determines whether the number is prime, but how do I go about that? Prove $(k,n+k)=1$ iff $(k,n)=1$ (a) Prove $(k,n+k)=1$ iff $(k,n)=1$. (b) Is it true that $(k,n+k)=d$ iff $(k,n)=d$? (all variables are integers, (a,b) means gcd(a,b))  For (a), I can only get so far.  $(k,n+k)=1\ \Rightarrow\ kq_1+(n+k)q_2=k(q_1+q_2)+nq_2=1$.  Note that we don't yet have that theorem (from a different class) that says something like if $d=(a,b)$, then $d$ is the smallest (or is it biggest) number which can be made by $ak_1+bk_2$, (which I'm not quite sure how it would help, anyway). So I'm stuck. String.split() *not* on regular expression? I don't really get why these hyperbolic functions are named after trig functions. Can someone enlighten me? I have 24 reputation points, but SO chat is still giving me the message "you must have 20 reputation...." Why can't I join the chat? Discrete and compact subset must be finite A stochastic process is a process that evolves over time, so is it really a fancier way of saying "time series"? How to colorize an image as in the example? Aside from the repetitive appearance of the black cat, I can't remember seeing any living animals, either inside the Matrix simulation or in Zion.  How come? Is there an in-universe explanation? Proving that if $V$ is an inner product space and $U_1, U_2$ are subsets, then $U_1 \subset U_2$ if and only if $U^{\perp}_2 \subset U^{\perp}_1$ How does body fat leave your body? So I know that it’s not from tears or sweat because they are composed of mainly water and sodium, it’s not from going poo or pee as poo and pee are made of the parts of food that supply your body with no nutrients and your body also doesn’t “burn body fat” because there is a theory that no matter is ever destroyed so it’s none of those but another thing is it’s not your hair, ear wax, finger nails or anything of that sort because people can lose over 17 pounds in 3 months but you can’t build up that amount of hair , ear wax or whatever else in three months so how does body fat leave your body What's difference between shadowing and overriding a method in C#? Does it make a difference if your URL path ends in a trailing slash or not? Does it make any difference to SEO ratings what-so-ever if your url has a trailing slash:  http://www.example.com/some/slug/paths/   as opposed to one that does not:  http://www.example.com/some/slug/paths Are code questions without an attempt now on topic