Orbital presheaves in equivariant infinite loop space theory

Let $G$ be a finite group.

Using a new kind of operad, we axiomatize and explore an infinite loop space machine that constructs (genuine) $G$-spectra from suitably structured functors on orbital presheaves, which are just contravariant functors from the orbit category of $G$ to based spaces.

The theory leads unexpectedly to a new operadic description of Mackey functors and hence to a definition of ``topological Mackey functors" and a construction of their associated $G$-spectra.

It also leads to Picard $G$-spectra, Azumaya ring $G$-spectra, and Brauer $G$-spectra.

These constructions raise many unanswered questions.