### Computation and the Periodic Table II

#### Posted by John Baez

On Tuesday my wife Lisa and I are flying back from Paris to Los Angeles, and then taking the long shuttle ride from the airport back home to Riverside. But on Wednesday we’re driving back into LA. And then on Thursday morning at 8:30, if I don’t oversleep, I’m giving a talk here:

- Logic in Computer Science (LICS 2009), UCLA, August 11-14, 2009, program chair Andrew Pitts.

It’s called Computation and the periodic table, and you can see the slides now. Comments and corrections are welcome!

Devotees of the $n$-Café will note that I gave a talk with a suspiciously similar title over a year ago. What’s new about this one?

Well, it’s not *drastically* different. But I’ve thought a lot more about 2-categories and the $\lambda$-calculus, so this goes into a bit more detail about that. And also there’s more of a focus on physics. Last year’s conference was on algebraic topology and computer science; now it’s logic and computer science — but I’ve been invited to talk about connections between these subjects and physics. So, I’m trying hard to explain how a 2-category of

- data types,
- terms, and
- rewrite rules

can resemble a 2-category of

- $D$-branes,
- states of a topological open string theory, and
- operators between open string states

and how this fits into the overall perspective of the ‘Periodic Table’ of $n$-categories. Doing this with any precision in one hour seems impossible, so I’m just trying to convey a rough flavor of the idea, while pointing people to a webpage for references that provide more details.

As with the previous incarnation of this talk, you understand it once you fully grok what these pictures mean:

## Re: Computation and the Periodic Table II

Any idea what the registration fee is for nonmembers?

The registration page will not show the fees until AFTER you fill out the form (?!)