Collages of string diagrams
Abstract. We introduce collages of string diagrams as a diagrammatic syntax for glueing multiple monoidal categories. Collages of string diagrams are interpreted as pointed bimodular profunctors. As the main examples of this technique, we introduce string diagrams for bimodular categories, string diagrams for functor boxes, and string diagrams for internal diagrams.
Bimodular profunctors (or the version of Tambara modules apt to Bimodular categories) provide the necessary structure to consider independent pieces of string diagrams. This explains how the syntax for strong monoidal functor boxes works, but also the theory of open internal string diagrams. As a first example, we introduce string diagrams for bimodular categories: we use them for encoding a race condition in bimodular string diagrams.