What does a square-bracketed index after an NSArray mean?
What are the details of "Objective-C Literals" mentioned in the Xcode 4.4 release notes?
I know that : $\mathbf{Q}(\sqrt{2}) = \mathbf{Q}+ \sqrt{2} \mathbf{Q}$ , but then what is $\mathbf{Q}(\sqrt{2},\sqrt{3})$? Bound for the correlation of three random variables Motivation behind the definition of ideal class group Why does logging in to Stack Overflow keep me signed in to my Gmail email after logging out and regardless of the Stay signed in checkbox?  Steps to reproduce:   Browse to  and confirm you are logged out Browse to  and confirm you are logged out Click login Click Google Enter Email/Password and confirm Stay signed in is unchecked Click Sign in Click logout (up top) Click Logout (down below) Browse to  and confirm you are still logged in Click Sign out &lt;- Shouldn't clicking Logout on Stack Overflow be doing the same thing as this? Browse to  and confirm you are logged out     Answers are making sense but my frustration is that clicking Logout (twice) on StackOverflow essentially does nothing. If I proceed to click login and Gmail I am immediately authenticated because I still have an active Gmail cookie. In order to effectively logout I need to click Logout twice on Stack Overflow and then manually browse to  and Sign out. What happens to options held during a reverse stock split? I held 1 put option for 100 shares of USO that expires on May 8. Yesterday, USO underwent an 8:1 reverse stock split. My options are now for USO1 instead of USO, but what does that mean?  The strike price hasn't changed, so does that mean that my option will expire worthless as it's unlikely the stock will drop (significantly) to back below the strike price? I want to prove that in an infinite dimensional normed space $X$, the weak closure of the unit sphere $S=\{ x\in X : \| x \| = 1 \}$ is the unit ball $B=\{ x\in X : \| x \| \leq 1 \}$.  $\\$  Here is my attempt with what I know:  I know that the weak closure of $S$ is a subset of $B$ because $B$ is norm closed and convex, so it is weakly closed, and $B$ contains $S$.  But I need to show that $B$ is a subset of the weak closure of $S$.  $\\$  for small $\epsilon &gt; 0$, and some $x^*_1,...,x^*_n \in X^*$, I let $U=\{ x : \langle x, x^*_i \rangle &lt; \epsilon , i = 1,...,n \} $  then $U$ is a weak neighbourhood of $0$  What I think I need to show now is that $U$ intersects $S$, but I don't know how. Are all electrons identical? Why should two sub-atomic (or elementary particle) - say electrons need to have identical static properties - identical mass, identical charge? Why can't they differ between each other by a very slight degree? Is there a theory which proves that?  Imagine an alien of size of order of Milky-way galaxy examining our solar system with a probe of size of 10's of solar system dimension and concludes that all planets are identical. How can I install Minecraft? I have tried many tutorials but none of them are clear enough. I have also tried installing it using Wine but it won't update and Wine goes gray and stops working.  Does anybody know an easy way to install Minecraft though the Java file without using Wine? Getting filesystem path of class being executed Open Safari / Google Chrome developer tools programmatically from JavaScript I want to use a very long USB cable to place a webcam in a different room. The maximum length that I found was five meters.   What is the maximum length of a USB cable? What is the maximum length achievable when using USB extension cables? To show that either $R$ is a field or $R$ is a finite ring with prime number of elements and $ab = 0$ for all $a,b \in R$. When I press the power button on my Epson WorkForce WF-3520 printer, it starts up normally, but shuts down within 30 seconds. Ten seconds later, it starts itself and the stop/start cycle is repeated again and again. This has only started happening today (6th December 2016). I'm using the plugin  which registers it's own post type but the capability is assigned to "post".   I want to change it to "manage_options".  Is there a correct way without altering the plugin to do that? Calling a hook, a function or whatever?   public function register_post_type() {      $labels = array (         'name'               =&gt; _x( 'Custom Code', 'post type general name' ),         'singular_name'      =&gt; _x( 'Custom Code', 'post type singular name' ),         'menu_name'          =&gt; _x( 'Custom CSS &amp; JS', 'admin menu' ),         'name_admin_bar'     =&gt; _x( 'Custom Code', 'add new on admin bar' ),         'add_new'            =&gt; _x( 'Add Custom Code', 'add new' ),         'add_new_item'       =&gt; __( 'Add Custom Code' ),         'new_item'           =&gt; __( 'New Custom Code' ),         'edit_item'          =&gt; __( 'Edit Custom Code' ),         'view_item'          =&gt; __( 'View Custom Code' ),         'all_items'          =&gt; __( 'All Custom Code' ),         'search_items'       =&gt; __( 'Search Custom Code' ),         'parent_item_colon'  =&gt; __( 'Parent Custom Code:' ),         'not_found'          =&gt; __( 'No Custom Code found.' ),         'not_found_in_trash' =&gt; __( 'No Custom Code found in Trash.' ),     );     $args   = array (         'labels'              =&gt; $labels,         'description'         =&gt; __( 'Custom CSS and JS code' ),         'public'              =&gt; false,         'publicly_queryable'  =&gt; false,         'show_ui'             =&gt; true,         'show_in_menu'        =&gt; true,         'menu_position'       =&gt; 100,         'menu_icon'           =&gt; 'dashicons-plus-alt',         'query_var'           =&gt; false,         'rewrite'             =&gt; array ( 'slug' =&gt; 'custom-css-js' ),         'capability_type'     =&gt; 'post', // &lt;--- I want to manipulate this         'has_archive'         =&gt; true,         'hierarchical'        =&gt; false,         'exclude_from_search' =&gt; true,         'menu_position'       =&gt; null,         'can_export'          =&gt; false,         'supports'            =&gt; array ( 'title' ),     );      register_post_type( 'custom-css-js', $args ); }   The above code is in custom-css-js.php lines 200-239. prove or disprove: For a prime number p, there is a positive integer n such that $p+1 $= $n^2$ if and only if $ p = 3.$ Prove or disprove: For a prime number p, there is a positive integer n such that $p+1 $= $n^2$ if and only if $ p = 3.$  first im trying to proof if p is prime number there is positive integer n such that $p+1=n^2$ implies $p=3$  suppose there is positive n integer such that $p+1=n^2$ and prove that $p=3$. $p=n^2-1=(n+1)(n-1)$ since $p$ is prime $n-1=1$,$ n = 2 $ $p+1=4$ $p=3$ hence it is proved that $p=3$  now if $p=3$ implies there is positive integer n such that $p+1=n^2 $  $p=3$ and p is prime  $p+1=n^2$, $4=n^2$, $n2$ or $n=-2$ hence it is proved that there is positive integer $n$ such that $p+1=n^2 $  is my proof correct? and also for prime number can i write $n+1=1$ instead $n-1=1$? My friend and I are planning a vacation to Ireland later this year. We'll be there for a week, flying into Dublin and then renting a car and driving around the country.  Both of us are 23. Are there any age restrictions on renting cars in Ireland? What would be the cheapest/best option for us? Using ST_Union in PostGIS I have a spatial table (polygons,polylines) in a database. These are digitized by multiple people. For example, a state is divided into multiple Grids and given to multiple people to digitize using QGIS; which is connected to a postgres database. Now, I have to merge all those polygons and polylines. I don't know how to do this via ST_Union. I Used the following snippet to merge the polygons and polylines CREATE TABLE schema_name.polygon_un2 AS SELECT upg.un_geom,npg.Column1,npg.Column2,npg.Column3,npg.Column4,npg.Column5  FROM (  SELECT st_union(the_geom) As un_geom,(   SELECT oid FROM schema_name.polygon    WHERE oid = 100748191   ) FROM schema_name.polygon WHERE oid IN (100748191,100763519)  ) upg  INNER JOIN schema_name.polygon npg ON npg.oid = upg.oid;   DELETE FROM schema_name.polygon WHERE oid IN (100748191,100763519);  I have the interesecting polygon oid in a Seperate Table, I want to do this process in an update query and that should be a dynamic plpgsql function.  Green : Grid , Other : Polygon But This snippet did not work !! The snippet which i expect is  It should create a new row for the merged polygons and polylines (eg oid - 1 and 2 merged to oid 3).  The polygons which are not merged (eg 1 and 2 should be deleted) Can you help me with my software dependency issue? This is a  about Compile Dependencies and Package Management.    I have a question regarding compiling ports/software or installing RPMs on my *nix server.  When I try to do this I receive lots of messages about missing dependencies.  Can the Server Fault community please help? Quantum teleportation and no-communication theorem According to the Wikipedia article for the :     In very rough terms, the theorem describes a situation that is analogous to two people, each with a radio receiver, listening to a common radio station: it is impossible for one of the listeners to use their radio receiver to send messages to the other listener. This analogy is imprecise, because quantum entanglement suggests that perhaps a message could have been conveyed; the theorem replies 'no, this is not possible'.   According to the Jet Propulsion's recent article on quantum teleportation:   they can effect an entangled photon (B) with another photon (A) to change the state of the other entangled photon.  Doesn't this contradict what the no-communication theorem states ? What is the point of the Red Thread/Tape around evidence or newspaper clippings? I have seen in a lot-lot of movies that the person who searches for a crime or another person creates a web of red tape or wire around the newspapers and evidence he acquires. I never guessed its usefulness and am therefore asking why do they do it?  Here is an illustration I created: