Gerard Westendorp has a real knack for geometry, and here is his answer. Here is Thurston’s procedure. First draw the lattice of Eisenstein integers in the complex plane: ...

And the course feels like it’s mostly converging with any other set theory course, just with the special feature that everything remains resolutely isomorphism-invariant. This week we constructed N ...

Projects range from applied category theory to logic, programming languages, and science, technology, and society. Specific topics for 2025 include, but are not limited to: Computational category ...

Are you interested in using category-theoretic methods to tackle problems in topics like quantum computation, machine learning, numerical analysis or graph theory? Then you might like the Adjoint ...

Nov 2, 2024 You can now apply for the 2025 Summer Research Associate program at the Topos Institute! The deadline to apply is January 17, 2025.

Nov 7, 2024 00:45 Here’s a way to argue that Gerard’s solution to my puzzle is correct. Thurston showed that any star of the ...

I haven’t been carefully following quantum field theory these days, but some folks on the Category Theory Community Server asked me what I thought about recent work using the ‘amplitudohedron’ and ...

Previously: Part 5. Next: Part 7. A category theorist might imagine that a chapter with this title would be about constructing colimits, and they’d be half right.

I didn’t want to drown the students in notation, so I didn’t give precise definitions of “property” and “formula”. Instead, I aimed to give them practical tools that would apply to situations they’re ...