Categorical generalization of MacDowell Mansouri gravity coupled to Kalb Ramond fields

In this work we generalize the MacDowell-Mansouri theory of gravity using strict 2-groups. To achieve this, we construct the categorical generalization of the ISO(4,1) group, which we call the de Sitter 2-group. We then proceed to generalize the MacDowell-Mansouri theory in two different ways. First, as a Yang-Mills-type theory, where the symmetry is explicitly broken to obtain an Einstein-Cartan theory coupled to Kalb-Ramond fields. And second, by using the categorical generalization of the BF theory, called 2-BF theory, which after the addition of some symmetry breaking and constraint terms gives the same Einstein-Cartan theory coupled to Kalb-Ramond fields plus some extra topological terms.