The higher algebra and geometry of monoidal bicategories
Raffael Stenzel
TL;DR
The paper provides a higher-categorical generalization of classic 1-dimensional results by identifying braided, sylleptic, and symmetric monoidal bicategories with $\mathsf{E}_k$-monoids in the cartesian $\infty$-category $\mathrm{BiCat}^{\times}$. It builds a bridge between 2-dimensional bicategorical algebra and $\infty$-categorical operad theory via little-cubes geometry, Additivity, and diagonal reflections, enabling controlled extensions of associative structures. The authors develop initial-segment techniques and a robust homotopical framework (via Lack’s model structure and the Gray monoid setting) to prove precise equivalences between bicategorical symmetries and $\mathsf{E}_k$-algebra structures. The results unify and extend Joyal–Street-style descriptions to the bicategorical level, with potential applications to centers, semi-strictification, and higher-categorical coherence phenomena in topology and representation theory.
Abstract
We show that braided, sylleptic and symmetric monoidal bicategories are precisely the $\mathsf{E}_k$-monoids in the cartesian monoidal $(\infty,1)$-category of bicategories for respective integers $k$. To manage the underlying computations, we use the geometry of the little cubes operads to mediate between the 2-dimensional algebra underlying the former and the $\infty$-categorical algebra underlying the latter.
