## Categories of comodels

### Richard Garner – 12 August 2020

Any algebraic theory gives rise to a category of set-based comodels which is comonadic over Set. We prove that the categories of comodels so arising are precisely the presheaf categories. We also explain that the categories of topological comodels of algebraic
theories are precisely the categories of diagrams on prodiscrete source-etale topological categories.

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