PlanetPhysics/Category of Borel Groupoids

The category of Borel groupoids ${𝒢}^B$ has, as its [[../TrivialGroupoid/|objects]], all [[../InvariantBorelSet/|Borel groupoids]] Failed to parse (unknown function "\grp"): {\displaystyle \grp_B} and, as its [[../TrivialGroupoid/|morphisms]] the Borel groupoid [[../TrivialGroupoid/|homomorphisms]] $h_B$ between Borel groupoids.