I'd really like to continue writing about AI-related technical stuff on LW.

Please do.

Would removing the word "obvious" satisfy your complaint?

You could go all mathematician and use 'trivial'. ;)

I think it would also help if you spelled out "Peano arithmetic" in the title instead of "PA." After reading the title, I had no idea what this post would be about.

When reading a technical post, it would be nice to see something like an "assumed reader's background" note before all the gory details. And maybe a non-technical summary for the rest of us.

For example, in your case you could state that the target audience is (say) a 3rd year math undergrad or higher, familiar with the concepts of <...> and <...>

Perhaps you could put something in the title or first line of the post to signal that it will be (a) only of interest to people who enjoy mathematical philosophy and (b) not indicative of the kind of writing normally seen here. The fact that similar posts of yours have attracted readers to LW is, I acknowledge, evidence against my previous comment.

Also please do omit the term obvious from future articles. It's infuriating (for me at least) to read technical articles and not understand something the author has labeled "obvious".

If possible you might want to motivate why whatever you have written provides insight into rationality. EY, I think, at least eventually always does this with his writings.