Is there a one visa or any paper that lets you enter (almost) any country in the world? For example, you are trusted and record-free citizen of couple countries and you sign something that makes you allowed to enter (almost) any country.
I understand that you have to have visas to enter some countries, but I was wondering whether you have to pay for each visa separately or you can get a visa to go everywhere. You see videos and lists on what you should pack to travel the world, but no lists on the documentation needed.
is there any way to decode string? How can one motivate the relativistic momentum? Cannot add a NOT NULL column with default value NULL in Sqlite3 If $x^{2}-x\in Z(R)$ for all $x\in R$, then $R$ is commutative. If $x^{2}-x\in Z(R)$ for all $x\in R$, then $R$ is commutative.  I need to proof this theorem and I have something like this below. However, I do not know how to continue this proof.   $(x+y)^{2}-(x+y)=x^{2}+xy+yx+y^{2}-x-y=(x^{2}-x)+(y^{2}-y)+xy+yx\in Z(R)$  so $xy+yx\in Z(R)$ To turn off my system, I can use one of these three commands:  sudo halt   Or:  sudo poweroff   Or:  sudo shutdown -h now   What are the differences between these commands, or are they all just aliases of each other? Sequence of sets $f_n$ that converge almost everywhere to $f$ but not almost uniformly to $f$? What is the mechanism by which magnetic fields do work? I've seen some conflicted answers to this question in texts and on the web, in the case of a dipole, for example.   Do magnetic fields do work directly, or is it their induced electric fields that do work? How to make a model cast shadows onto the world texture/background? In most of my models, I usually end up setting a world background using an HDRI image of some kind or another. This has always been really useful for lighting in general or as a background for my final render.  But what if I want my model to look like it is interacting or touching part of the background? For example, in the image below that I found, the modeled objects look like they're part of the scene, and even appear to cast shadows on the ground. How can I do this? I have a JavaScript object like the following:  var p = {     "p1": "value1",     "p2": "value2",     "p3": "value3" };   Now I want to loop through all p elements (p1, p2, p3...) And get their keys and values. How can I do that?  I can modify the JavaScript object if necessary. My ultimate goal is to loop through some key value pairs and if possible I want to avoid using eval. What is a 'Closure'? I asked a question about Currying and closures were mentioned. What is a closure? How does it relate to currying? Unable to log in to Stack Exchange Any reason to have a strong user password? I recently decided to change my (very) strong user password to something trivial.  This was mostly to eliminate frustration with typing a long password each time I sudo or whatever.  My question is, is there any reason to have a strong user password? considering that most services which I run on my box do not use PAM for auth:   apache2 - uses .htpasswd for access   sshd - only private keys allowed   transmissiond - uses its own http auth   mpd - uses its own auth   samba - limited to LAN   Physical access to the box is out of the question. I would like to be able to execute a SOQL query that will allow me to see which users have access to a certain record type for a certain object.  For example, if I have a case record type called Phone Team, I would like to make a query that returns the names of all the users that have been assigned the Phone Team record type, as can be seen in the native user interface in a profile's Object Settings page.  So far I have managed to get a query that can get the names of all the users that have, for example, read access to the case object:  SELECT Assignee.Name FROM PermissionSetAssignment      WHERE PermissionSetId IN          (SELECT ParentId FROM ObjectPermissions WHERE SObjectType = 'Case'               AND PermissionsRead = true AND Parent.IsOwnedByProfile = true)   However, there doesn't seem to be any way to access record type assignment in the same way that you can object permissions.  I see from  that the info can be obtained via the metadata API, but I would much prefer to do it by SOQL if possible.  Thanks How to recenter an object's origin? So, I'm working creating a lamp... yes, newbie here.  After modeling for a bit, I noticed that my point of origin was no longer the center of my object:    How to I reset an object origin point to the center of it's geometry? Splitting of prime ideals in algebraic extensions $\lim_{x \to 0} {1-x\cot x\over x^2}$ A familiar limit, but in general form . I'm trying to find $\int x^x \, dx$, but the only thing I know how to do is this:  Let $u=x^x$.  $$\begin{align} \int x^x \, dx&amp;=\int u \, du\\[6pt] &amp;=\frac{u^2}{2}\\[6pt] &amp;=\dfrac{\left(x^x\right)^2}{2}\\[6pt] &amp;=\frac{x^{2x}}{2} \end{align}$$  But it's certain that this isn't the correct way to evaluate that, and the answer must be wrong. Interaction of Invoke Duplicity and Misty Step Maybe the concept, why it's used, and an example.