Ask HN: What's new in theoretical CS these days?

I could be wrong, but I think the OP was asking about "CS Theory" meaning the branch of computer science that deals with the theory of computation. Turing Machines, Automata, The Halting Problem, etc. Although those things are all old. I'm not sure what's new, so I can't answer his question.

That isn’t theoretical computer science. In this day and age, that’s firmly in the hands of engineers.

And while AI might be the current big thing, I don’t imagine it will be at the forefront of engineering. I think quantum computing takes the prize there.

This is really not TCS. I’d say ML foundations count as part of TCS, like VC dimensions, learning theory, and all kinds of complexity.

Programming language pl research in haskell omega has a lot of bleeding edge theoretical cs stuff too

Lisp has been making a comeback since the 60s

Except that for someone outside CS theory it will be hard to tell what is routine and what is ground-breaking. The proceedings for the recent editions of top theory conferences are here:

- FOCS (Foundations of Computer Science) https://www.computer.org/csdl/proceedings/focs/2022/1JtvJWOs...

- STOC (Symposium on the Theory of Computer Science) https://dl.acm.org/doi/proceedings/10.1145/3519935

- SODA (Symposium on Discrete Algorithms) https://epubs.siam.org/doi/book/10.1137/1.9781611977554

They're mostly paywalled but conference or full versions can usually be found on arxiv.org, and there are successful efforts to host paywalled papers illegally for the public good.

Personally, I am impressed by the progress on approximate counting and sampling. Developments include localization schemes (FOCS), average-case entropic independence (FOCS), the sampling/counting Lovász local lemma in (FOCS and SODA), and approximate counting with global constraints (STOC).

> computational category theory

There's also the compositional game theory which is based on it:

https://arxiv.org/abs/1603.04641