Modelling Interconnected Systems with Decorated Corelations

Here at the Simons Institute workshop on compositionality, my talk on network theory explained how to use ‘decorated cospans’ as a general model of open systems. These were invented by Brendan Fong, and are nicely explained in his thesis:

• 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...