Proofs in braided monoidal categories using strings
Braided monoidal structures occur on categories whose objects are representations of (quantum) groups and on categories whose morphisms are low-dimensional manifolds. My purpose is to explain the use of string diagrams in these categories, motivated by linear algebra. As an application I shall use a string argument, influenced strongly by the work of Markus Rost and his students, to reprove the existence of very few dimensions on which division algebra structures can exist.
Professor Ross Street, Macquarie University