Casting a List back from object returns a System.InvalidCastException C#
Deep cloning objects
A cardinal $\kappa$ such that $2^{\lambda}<\kappa$ for all $\lambda<\kappa$ is regular? A cardinal $\kappa$ such that $2^{\lambda}&lt;\kappa$ for all $\lambda&lt;\kappa$ is regular?  I would appreciate very much an answer I just want Telegram to be run and I have added it to startup apps. The point is that I need it to be minimized. Any commands? As the title suggests, I'd like to prove that the sum $$ \sum_{n=2}^\infty (\ln n)^{- \ln n} $$ is finite.  The root and ratio test both fail here, but  suggests that there is a comparison that can be used to show convergence.  The only thought I have is that it may help to write the terms as $e^{-\ln(n)\ln(\ln(n))}$, but this has not led me to any particular insight.  Any ideas are appreciated. How to prove that $p-1$ is squarefree infinitely often, where $p$ is prime?  I had thought of using Dirichlet's theorem on arithmetic progressions.  The number of squareful values of $p-1$ less than or equal to $n$ is bounded by $\sum_{q}{\pi_{q^2,1}(n)}$, each term $\pi_{q^2,1}(n) \approx \frac{\pi(n)}{q \cdot (q-1)}$, and $\sum_{q}{\frac{1}{q \cdot (q-1)}} \lt 1$.  But using for example , the possibility is open that the error in each approximation for $\pi_{q^2,1}(n)$ may continue to increase with $q$, and since the sum runs up to $\sqrt{n}$, this argument is invalid.  Is there a more refined version of Dirichlet's theorem that can be used to circumvent this issue?  Or an entirely different way to prove this statement? In chat, the short code [metaso] expands to http://meta.stacexchange.com/ (no typo, the missing 'k' is the bug I'm reporting).  (And since this is too short a bug report, I'll note that I think that [metaso] should probably point to .) Do I need a visa to transit (or layover) in the Schengen area? I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows:  Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland Deriving Sum of a Geometric Progression Long lay over in Seoul. Do I need a visa as a Filipino citizen? I'm a Filipino immigrant from USA about to visit home in December.  I have a 14-hour lay over in Seoul,  South Korea.  Do I need a visa to leave the airport to do a little sightseeing? the converse of Pythagoras Theorem Suppose I have a python object x and a string s, how do I set the attribute s on x? So:  &gt;&gt;&gt; x = SomeObject() &gt;&gt;&gt; attr = 'myAttr' &gt;&gt;&gt; # magic goes here &gt;&gt;&gt; x.myAttr 'magic'   What's the magic? The goal of this, incidentally, is to cache calls to x.__getattr__(). Constant term in Lagrangian Why can we always drop any constant term in a Lagrangian density in quantum field theory?  This issue is somehow related to the constant term being some kind of cosmological constant.  Can you please explain this issue? How to look up a symbol or identify a letter from a math alphabet or other character? I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out? How can I determine the name of the Bash script file inside the script itself?  Like if my script is in file runme.sh, then how would I make it to display "You are running runme.sh" message without hardcoding that? I exported a map and everything looks fine when viewing the PDF. But when printing it on my plotter, all the text disappears. The scale bar would bring but the text associated to the scale bar wouldn't. The title block also disappears. I've tried messing around with the settings. I've checked/unchecked &quot;Embed All Document Fonts&quot; and &quot;Convert Marker Symbols to Polygons&quot;. I'm not sure what I'm doing wrong here. What's weird is I exported this map a few weeks ago and it printed just fine. Today, I needed to make a change to the map and exported it out, and now I am experiencing this issue. I must have changed one of the export settings in the past few weeks but I'm not sure what it is. Has anyone experienced this? How can I revert a config file back to the originally installed version after I have edited it? I want to revert a file in /etc/ back to its originally-installed form. I have edited the file since it was installed. How can I revert this config file? Apt is smart enough not to overwrite edited config files, so how do I tell it that I want it to do so?  For argument's sake, let's say that I want to revert the file /etc/foo.conf from the package foo. How to call child component controller function/helper from Parent Component Controller When we eat something, after munching and swallowing a bite, we are strongly stimulated to have one more bite. What is the taste that causes this effect? I have installed a package using snap and I need to modify one of the files but when I try to change its ownership or permissions, I always get the following message:  sudo chmod +x ./my_file.js chmod: changing permissions of '/snap/my_app/my_file.js': Read-only file system   How can I modify files that are installed via snap? If $\operatorname{ran} F \subseteq \operatorname{dom} G$, then $\operatorname{dom}(G \circ F) = \operatorname{dom} F$. Explicit space character? I'm wondering about the best way to do an explicit space character (I don't even know what it's properly called), like the ones you get in the \begin{verbatim*} environment. The closest I've found is  \sqcup   in math mode, but it seems like a bit of a hack to me. Is there any text symbol for what I'm looking for?