Conceptually it seems like a derived class should be able to override a readonly property with a read write property.  Why isn't this possible?  Public Class Base      Protected _name As String     Public Overridable ReadOnly Property Name() As String         Get             return _name         End Get     End Property  End Class  Public Class Derived     Inherits Base      Public Overrides Property Name() As String         Get             Return MyBase.Name         End Get         Set(ByVal value As String)             _name = value         End Set     End Property  End Class
Why is the following C# code not allowed:  public abstract class BaseClass {     public abstract int Bar { get;} }  public class ConcreteClass : BaseClass {     public override int Bar     {         get { return 0; }         set {}     } }      CS0546 'ConcreteClass.Bar.set': cannot override because 'BaseClass.Bar' does not have an overridable set accessor
iOS app blocking actions with "you must join this site" message for sites I belong to Is there an IDictionary implementation that, on missing key, returns the default value instead of throwing? Finding the maximum likelihood estimators for this shifted exponential PDF? Consider a random sample $X_1, X_2, \dots, X_n$ from the shifted exponential PDF $$f(x; \lambda, \theta) = \begin{cases}\lambda e^{-\lambda(x-\theta)} ;&amp; x \geq \theta\\                     \theta ; &amp;\text{Otherwise}\end{cases}$$ Taking $\theta = 0$ gives the pdf of the exponential distribution considered previously (with positive density to the right of zero). a. Obtain the maximum likelihood estimators of $\theta$ and $\lambda$. I followed the basic rules for the MLE and came up with: $$\lambda = \frac{n}{\sum_{i=1}^n(x_i - \theta)}$$ Should I take $\theta$ out and write it as $-n\theta$ and find $\theta$ in terms of $\lambda$? Edited vs emitted - why one t vs two t's Why does "edited" have one "t" and  and "emitted" has two? "Edit" and "emit" are so similar in spelling and pronunciation.  I keep wanting to type "editted" for some reason. How to use Font as a variable? How can I make 3D Text in Russian? I've seen a similar question on BSE about entering foreign languages into 3D Text, but it doesn't help. I've tried using two different fonts (both of which support Russian). I've tried enabling International Fonts in Blender's User Preferences, but it doesn't work as well. It either types English text with Greek letters or displays empty vertical rectangles.   If anyone has been able to add text in any foreign language, please let me know.  I actually found out that it can be easily done through Text Editor, which would be probably the best way for me since I would prefer to paste my text. Can anyone perhaps guide me through? Difference between "try to do" and "try and do" What is the difference between try to do and try and do?  To me (non-native speaker), asking someone try and do this seems a bit rude. It's like saying you can try all you want but this must be done: try and fail is not an option. However, asking someone try to do this means I am asking you to try: success is bonus, failure is OK. What can you say about $f$ and $g$ in the case that $fg$ is 1) Injective, 2) Surjective - Cohn - Classic Algebra Page 15 Question: Are my proofs below valid?   In both cases we are using: $f:A\to B, g: B\to C$  Notation of your type converted: $(g\circ f)(x)=g(f(x))=xfg$    If $fg$ is injective what can be said about $f$ and $g$?  If $fg$ is injective then $f$ is injective:  Proof:  $(x_1fg = x_2fg \implies x_1=x_2)$  $x_1fg=x_2fg$ is clearly true when $x_1f=x_2f$  Which requires $x_1=x_2$, hence $f$ is injective.  If $f$ were not injective, then $x_1fg\ne x_2fg$  $\blacksquare$    If $fg$ is surjective what can be said about $f$ and $g$?  If $fg$ is surjective then $g$ is surjective:  Proof:  $(\forall c\in C)(\exists a\in A) |( a(fg))=c$  This means for $g$ every element must have had been mapped to. How can this be proved Mathematically?  well $(af)g=c$ is surjective, hence $(af)=(b\in B)$ and $bg=c$  $(\forall c\in g)(\exists b\in B)|(bg=c)$  Hence $g$ is surjective.  $\blacksquare$ Writing ISO 19139 compliant XML metadata from spreadsheet? I am looking at a way to migrate the metadata from a spreadsheet into ISO 19139 compliant XML metadata documents for a collection of shapefiles. I can parse the data out of the spreadsheet into strings without issue however I am getting lost on how to take those strings and use them to populate the elements.   This example:  covers most of what I want to do, however I would need to generate the tree beforehand based on the ISO 19139 schema. PyXB seems to have schema bundles for OpenGIS but I would like some insight on how to connect everything. In a situation where say a group (or at least a plurality) of men is being addressed — for example on a sign passed by many married men — which is correct?  &quot;Remind your wife.&quot;  or  &quot;Remind your wives.&quot; Is a function defined at a single point continuous? Is a function defined at a single point continuous?  For example $f:\{0\}\to\{0\}$ defined by $f(x)=\sqrt{x}+\sqrt{-x}$ is a sum of two continuous functions and is therefore continuous, however for $f$ to be continuous, it has to have the limit $\lim\limits_{x_0\to x}f(x_0)=f(x)$ but it dosen't seem to have that limit. Label rows of a matrix by characters Does $\{f_ng_n\}\to fg$ uniformly? Adding 3 electron spins I've learned how to add two 1/2-spins, which you can do with C-G-coefficients. There are 4 states (one singlet, three triplet states). States are symmetric or antisymmetric and the quantum numbers needed are total spin and total z-component.  But how do you add three 1/2-spins? It should yield 8 different eigenstates. Which quantum numbers do you need to characterise the 8 states?  It is not as easy as using C-G-coefficients and the usual quantum numbers as for the total momentum the doubly degenerate 1/2 state and quadruple degenerate 3/2 state can describe only 6 or the 8 states. You will need an additional quantum number for the degeneracy.  So how do you get the result?  (I actually tried out myself with a large 8x8 matrix. The total spin 1/2 is each doubly degenerate. For the additional quantum number I chose the cyclic permutation. Spin 1/2 states are neither symmetric nor antisymmetric. But what is the usual way to derive this?)  EDIT: For reference I'm adding my results for up to 4 spins from some time ago:   If you recall the basics of quantum mechanics with matrices it is actually a straightforward matrix diagonalization and requires no specialized knowledge. However, you still need to find an additional operator which breaks degeneracy. I chose the cyclic permutation, which seems to do the job. Please refer to the below answer, since I haven't checked all details. Short story ID: Bouncing-Ball Time Travel A little help please. The story I'm looking for is probably late-50's to mid-60's, and may well have occurred in an SF magazine.  A professor is demonstrating his new time machine to a scientific audience. The machine looks like two large spheres touching each other. In operation, one is sent back into deep time (let's say, although my memory has dropped this particular datum, 10 billion years). It will then return to the present, then bounce off its twin and jump back half that temporal distance (5 billion years), return, bounce half again (2.5 billion years), etc. Each trip will take half the time (in present-day units) as the previous, so the whole thing will be over in a finite time.  Before anyone can stop him, he activates it. He begins lecturing the audience, asserting that whatever has happened has always happened. At decreasing intervals the sphere reappears and bounces with a resonant "Boing!". At each jump, the narrative establishes that the appearance of the sphere did change history, and these changes are reflected in the professor's speech.  So it becomes something like "(Boing!) And those who say that this is dangerous might as well be claiming that the day is not 26 hours long (Boing!) or that there are three moons, not seven (Boing!)", etc. And when the final (Boi-Bo-B-B-Boing!) fades away he raises his tentacles in triumph and cries, "See? Nothing has changed!" Windows 10 update broke my MBR / GRUB After I ran Windows 10 update this afternoon my partition table broke... I had dual boot with Windows 10 and Ubuntu 14 with Grub as the boot loader. The error that came up was "Error no such partition, Entering rescue mode... grub rescue>". I googled it,  about the boot-repair ISO, installed it on a USB, ran the repair, got this report, but still no luck:    Now the boot skips Grub entirely and goes to Windows boot manager which fails with "The boot configuration data for your PC is missing or contains errors". So now instead of dual boot I have zero boot. Thanks Microsoft.  Anyway can you guys help me interpret the disk info in the pastebin link? I don't remember my partition configuration but I believe Ubunut had slightlty less disk space than Windows. Questions I have:   Is the Ubuntu partition still there? Could it be the one named "Extended"? (sda4) Where would GRUB be? Gone? Can it be reinstalled? how?   I don't really care about the Windows partition anymore, but it would be nice to rescue Ubuntu. Last months I have lots of referrer spammers in my GA statistics. Their count is ~10x higher than count of legit visitors (my site is not very popular yet). I've turned on an option to hide known spammers in GA settings, but it didn't help at all. It seems these spammers are using scripts to spam directly to GA (i.e. they are not logged in my IIS).  Is there anything I can do to stop these spammers?    UPD 10 months later, and they started spamming using fake target page names... and Google is still doing nothing about it. Is there a privacy setting on Facebook that will stop the posting that is made on your friend's wall when you make a new friend?  I do not want this to appear on my friend's wall when I make a new friend Can't find Corruption What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.