My friend Jamie Vicary has been developing some of this software, and he demonstrated it at the Simons Institute workshop on compositionality. You can watch his demonstration here:

But since *Globular* runs on a web browser, you can also try it out yourself here:

• *Globular*.

You can see his talk slides:

• Jamie Vicary, Data structures for quasistrict higher categories. (Talk slides here.)

]]>• Brendan Fong, *The Algebra of Open and Interconnected Systems*. (Blog article here.)

But he went further: to understand the *externally observable behavior* of an open system we often want to simplify a decorated cospan and get another sort of structure, which he calls a ‘decorated corelation’. His talk here explains decorated corelations and what they’re good for:

https://www.youtube.com/channel/UCW1C2xOfXsIzPgjXyuhkw9g

and you can also see recorded talks.

The conference schedule has changed a bit from that shown on my blog article; the revised version is here.

]]>• John Baez, Compositionality in network theory, 6 December 2016.

and a video here:

Abstract.To describe systems composed of interacting parts, scientists and engineers draw diagrams of networks: flow charts, Petri nets, electrical circuit diagrams, signal-flow graphs, chemical reaction networks, Feynman diagrams and the like. In principle all these different diagrams fit into a common framework: the mathematics of symmetric monoidal categories. This has been known for some time. However, the details are more challenging, and ultimately more rewarding, than this basic insight. Two complementary approaches are presentations of symmetric monoidal categories using generators and relations (which are more algebraic in flavor) and decorated cospan categories (which are more geometrical). In this talk we focus on the latter.

This talk assumes considerable familiarity with category theory. For a much gentler talk on the same theme, see:

]]>With luck some of the lectures will be recorded, or at least slides will be available. I’m sorry you’re not active in this scene, as I’m trying to get up to speed on a lot of the computer science aspects. But you can at least listen in and say something now and then.

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