Getting exception when using linq
How to do multiple joins when using groupby in linq
What are the requirements for a (beta) site logo? What happens if you are refused entry between two countries? Last month, I was travelling on a backpacking trip across Russia and the Baltic states (Schengen zone). I'm an Indian by nationality. So I had to get the respective single entry visa for Russia and Schengen Europe.  At the border crossing into Estonia by road (at Ivangorod-Narva), I exited the Russian border with an exit stamp (so now I can't go back to Russia since I had a single entry visa). When I was at the immigration checkpoint of Estonia, I was heavily questioned on the intent of my travel to Europe while entering Estonia by road.   Though I finally got into Europe, It got me wondering - what happens if a foreign national is denied entry into a country not at the airport but by land between 2 countries he cannot go into ?  Generally, if you are denied entry at the airport the airline has the obligation to fly you back to your country. But what happens when you are stuck between two countries and you cant get into either ? What happens to you then ? Deleting array elements in JavaScript - delete vs splice Object of class mysqli_result could not be converted to string Exclude TeX.SE question titles from MathJax parsing in Hot Network Questions Recently, the TeX.SE question  got onto the Hot Network Questions list.  Like many questions on TeX.SE, it contains some TeX markup in its title.  Unfortunately, on , this markup gets parsed and rendered as math:    I propose that either:   the entire Hot Network Questions sidebar should be excluded from MathJax parsing by styling it with the tex2jax_ignore class, or at least, any hot questions from TeX.SE should be so excluded from MathJax parsing.   Or I suppose we could always implement , which asks for all questions with TeX in the title to be excluded from Hot Network Questions entirely.  That might be throwing out the baby with the bathwater, though.    Ps. This issue is partially masked by , which causes MathJax not to be rendered in many elements that are hidden by default and revealed using jQuery .show(), such as all but the first five questions in the Hot Network Questions sidebar.  The  user script contains a generic fix for that bug, so users who have it installed will see this issue more frequently, but it occurs even without SOUP whenever a question with TeX markup in the title happens to show up among the top five hot questions that are always visible by default. Is it acceptable to publish a paper using an affiliation with a former employer? Recently I've changed jobs, and consequently the field of research has also changed. But I'm still getting proposals for publications in the previous field, and it is interesting for me to accept some of them. My concern is about which affiliation to use: on one hand I gain all the knowledge in that field while working on the previous employer, also I hope they can cover my expenses related to the publication. On the other hand, I do not work for them anymore, and my current company has very little interest in my old field of research, and probably will not support it financially, but I think it is wise to mention them as well. As a compromise I'm thinking to put the previous employer in the affiliation, and the name of my new employer in the footnote, something like "currently at XYZ". Surely I'll discuss this issue with both, although the opinion of the community is also very valuable. I`m using the Newton-Raphson method for obtaining MLE for parameters for maximizing my objective function. At each iteration, I want to check that is the Hessian matrix negative definite or not and I see the Hessian matrix is not negative definite at some iterations. So, I want to use the Fisher scoring algorithm ( of derivation) In this situation, the Fisher information matrix is indefinite!! Is it possible? What are the reasons for this? Are the second-order derivatives wrong? Or are values of expectations incorrect? Why is spectrum obtained by sunlight, said to be continuous? My teacher spoke about atomic spectra today, and he explained that, unlike the spectrum obtained by analyzing the sunlight, the spectra of atoms are not continuous.     I have a question about this - even the sunlight has the radiations emitted by the atoms of the elements which compose the sun, still spectra is continuous, which is in opposition to the statement that atomic spectra is discontinuous. So, spectrum obtained by sunlight is continuous even though it atomic spectra. In order to account for spectrum obtained by the sunlight to be continuous and atomic spectra to be discontinuous, can we confirm that sun consists of all those elements (sodium, helium, neon, mercury, etc) which emit the colors of frequency belonging to visible region? Show that $\arctan(n)$ is irrational for all $n \in \mathbb{N}$ Find all $n\in\mathbb{N}$ so that there exist $x,y,z\in \mathbb{N}$ that solve:   $$(x+y+z)^2=nxyz$$   I tried to attack it finding solutions, but all the solutions doesn't seem to have something in common. For example:  $$ (x,y,z,n)=(1,1,1,9)$$ $$ (x,y,z,n)=(1,2,3,6)$$ $$ (x,y,z,n)=(1,4,5,5)$$ $$ (x,y,z,n)=(2,2,4,4)$$ $$ (x,y,z,n)=(8,8,16,1)$$  I was trying to solve this problem, but someone told me that a hint to solve it is using Vieta Jumping. I don't know how to use Vieta Jumping, so can anyone help me to understand how to apply Vieta Jumping and solve the problem? zero matrix to the power of 0 Why $0^0=I$?   I'd tried prove that considering $N^0$ where N is a Nilpotent matrix and then using the Cayley -Hamilton theorem  Thanks in advance. Why is everything floating in space so cold? Of course there is pretty hot stuff too. For example Suns.  But isn't the vacuum of space the perfect containment for heat? And shouldn't the rare collision with particles even heat up an object that floats around in space?  Why aren't they hot from time to time? Is it because they loose their heat by radiant heat?  And if so does radiant heat emission always occur until the object is the same temperature as the surrounding or does it depend on other factors? LaTeX: optional arguments with square brackets LaTeX is trying to add a missing $ that I don't want to the following code. Minimal working example:  \documentclass[letter,12pt]{article}  \newcommand{\monkeyBeans}[2][]{   \parbox{4in}{#1} }  \begin{document}  \parbox{4in}{$[a, b]$}   \monkeyBeans[$[a, b]$]{yo monkey}  \end{document}   If I try any of the following lines in my document instead of the call to monkeyBeans, there is no error:  \parbox{4in}{$[a, b]$}  \monkeyBeans[yo monkey]{$[a, b]$} \monkeyBeans[$(a, b)$]{yo monkey} \monkeyBeans{$[a, b]$}{yo monkey}   What is the deal with square brackets in optional arguments? Available US State or National business (or employer) database lists? This question dovetails with this post on .  I am familiar with some of larger, paid-for business registry's like  and .  While the detailed information their business listings database include (like # of employees, annual sales, industry code, etc) is fantastic, if you are on a limited budget, sometimes the cost of purchasing the data outweighs the value you can get from it.  If you have geocoding capabilities in house, one could potentially create a reasonable surrogate by spatially-enabling (geocoding) a publicly available business listing on your own.    If you were looking to take on this type of project, where would you start your research? Do you know of US agencies at a State or National level that maintain this type of information, AND are publicly available for download or minimal purchase? How to read ext4 partitions on Windows? Is there a way to read ext4 partitions from Windows? If so, what can I do? Let $(x_n)_{n\in \mathbb{N}}$ be a sequence of real numbers. A well known result is:     The sequence $(x_n)_{n\in \mathbb{N}}$ converges to $a\in \mathbb{R}$ if and only if every subsequence $(x_{n_k})_{k\in \mathbb{N}}$ converges to $a\in \mathbb{R}$.   Now, I'm working on an exercise which essentialy asks to prove the following:     The sequence $(x_n)_{n\in \mathbb{N}}$ converges to $a\in \mathbb{R}$ if and only if for every subsequence $(x_{n_k})_{k\in \mathbb{N}}$ there is a (sub)subsequence $(x_{n_{k_j}})_{j\in \mathbb{N}}$ which converges to $a$.   Now, one direction is trivial. If in fact $(x_n)_{n\in \mathbb{N}}$ converges to $a$, then by the result I've mentioned, every subsequence of $(x_{n})_{n\in \mathbb{N}}$ converges to $a$. Let then $(x_{n_k})_{k\in \mathbb{N}}$ be an arbitrary subsequence. In that case, we know that it is a subsequence of itself, and hence we've found a (sub)subsequence which converges to $a$.  The other way around seems quite complicated for me. The reason is as follows: I must assume that every subsequence $(x_{n_k})_{k\in \mathbb{N}}$ has a (sub)subsequence which converges to $a$ and the proof that the original one converges to $a$.  My problem is exactly that "a". If it had all (sub)subsequences converging to $a$, then by the result i've mentionted, the subsequence $(x_{n_k})_{k\in \mathbb{N}}$ would converge to $a$. In that case, we would have every subsequence converging to $a$ and the result would follow.  My idea to prove the claim was then:  First remember that a subsequence is the restriction of the original one $x: \mathbb{N}\to \mathbb{R}$ to an infinite subset $\mathbb{N}'\subset \mathbb{N}$. In that case a (sub)subsequence is the restriction of $\tilde{x} = x|\mathbb{N}'$ to an infinite subset $\mathbb{N}''\subset \mathbb{N}$. But since $\tilde{x}$ is the restriction of $x$ to $\mathbb{N}'$ and since $\mathbb{N}''\subset \mathbb{N}'$, the restriction of $\tilde{x}$ to $\mathbb{N}''$ is itself the restriction of $x$ to $\mathbb{N}''$.  In other words, every (sub)subsequence can be viewed as a subsequence of the original one. Considering this, by hypothesis every subsequence has a (sub)subsequence which converges to $a$. But by this argument, this means that we can replace every subsequence with a convergent one. And then we can use the result I stated.  Is my idea correct? Is this really the way to prove the claim? My only doubt is that I need every subsequence converging to $a$ to use the result. In this case I can't see how I can argue that this implies every subsequence converges to $a$.  How can I finish this proof? I created one event receiver and deployed it, but only users who are site collection admins are able to view this web part. I have included the SPSecurity.RunWithElevatedPrivileges but the same thing. What am I missing?  Below is my code   public override void ItemAdding(SPItemEventProperties properties)     base.ItemAdding(properties);     SPSecurity.RunWithElevatedPrivileges(delegate()        {SPWeb web = properties.OpenWeb();         base.ItemAdding(properties);         string name= web.Lists[properties.ListId].Fields["first name"].InternalName;          var list = web.Lists["location names"];    });} Who is the Community user? I see the  on the user page.  It seems to edit posts sometimes.  What is it? And why has it downvoted over 1800 times? See also: Can't move files to trash without any permission issues This is not like one of the cases addressed before - I've checked them all.  I've suddenly begun getting that message "... can't be put in the trash. Do you want to delete it immediately?" this morning in my Home directory only.  I have a Home partition (ext4, mounted properly) with symlinks for user folders like Downloads, Documents, etc. to folders with the same names in a Data partition (ntfs, mounted properly).  For example, I cannot move a file in Downloads folder to Trash when I try via Home, but no problem if I try via Data partition, although the file in question has the same ownership and permissions at both locations.  Also no problem at all with files in my Home folder, including sub-folders like Public that are not symlinked to my Data partition.  Interesting puzzle for me...  PS: Just upgraded to 15.04 but I don't think it matters... On second thought, it might perhaps be something to do with upgrading from Nautilus 3.10 to 3.14?  PPS: This bug has been finally resolved some time later in version 16.10, and no longer exists under Ubuntu 17.04. I'm looking for some sample code that will sort the list items in an HTML list by alphabetical order.  Can anyone help?  Here is a sample list for people to work with:  &lt;ul class="alphaList"&gt;     &lt;li&gt;apples&lt;/li&gt;     &lt;li&gt;cats&lt;/li&gt;     &lt;li&gt;bears&lt;/li&gt; &lt;/ul&gt;