I have asked here about Chaitin's constant level. It is ∆0/2.

@Evil Related?

It might be, but I have seen this bug several months ago.

Okay. Weird. It works with JS on the client, so I unless your browser has a very different JS engine (with bugs, maybe?) I'm not sure how this could happen. (Refreshing caches is always a good idea.)

@Evil interesting/ creative/ offbeat researcher. you might enjoy this article (sorry paywalled). actually chatted with chaitin many yrs ago in cyberspace. newscientist.com/article/mg16922814-800-the-omega-man

@Raphael not even remotely possible, fully conformant and since it works with edit, I would politely point to internal pipeline of site (wrap etc.)

@vzn thank you. Well I might have access.

About my comment about the "real interpreters" - ancient stuff, I do not have papers right now, but if somebody is profficient in that topic any comment into that would help. Maybe there is no longer distinction (and I am unaware of that).

@Raphael is there any chance that while looking for Arden lemma I have found your pdf?

@Evil Certainly. I have linked a write-up on a few places on SE.

Do you have equally cool write-up on Thompson and Brzozowski?

@Evil Afraid not. I prepared the Arden one for students back then. Nowadays, I would probably refer people to the reference question on Computer Science. ;)

(I seem to remember that my former colleague prepared another document on one of these algorithms, but I don't know which. I don't think it's online.)

Oh, ok. I know these algorithms, just good and checked reference is always handy ;)

Sure, figured.

Especially good one, because my teacher got this quirk that his book and script was full of errors, which he was aware of, but allowed people to bring book to the exam. And all poor students rewriting parts of book failed...

Oh no! O.O

Wouldn't he fix the bugs?

Of course not. He spotted them, students gave him list of errors and yet it was fully premeditated - he was enforcing people to attend lectures this way ;)

._.

Well, if it's common knowledge that the book contained errors, those who started copying stuff without checking it rigorously during their preparation failed correctly.

Well on one side it is bad to provide script with errors, on the other he was indeed correcting them during the lecture and told about the errors on the first lecture, so those who failed to show up more than twice to figure it out... That is on them.

@Evil Yup. There's a difference between "this is my book and it's your bible" or "these are the lecture notes, beware mistakes!"

In overall, it was even nice, there were extra points available for spotting mistakes in advance (from topics not yet presented). But since my book is covered with my handwriting... I was looking for bibles ;)

Hopcroft/Ullman?

Yes, of course, that is a must have, must know book. I just opt for having more than one.

I don't know any other English books for the basics, sorry. My Grundstudium was in German. ;)

If you have a good one, then it is not that big problem ;) I will probably be able to read it with slight help from dictionary.

The Gems of TCS?

That's on the shelf, unread. :> No, the one about automata, formal languages and computability.