A Classification of subgroups of SL(4,R) Isomorphic to R^3 and Generalized Cusps in Projective 3 Manifolds

This paper uses work of Haettel to classify all subgroups of PGL(4,R) isomorphic to (R^3 , +), up to conjugacy. We use this to show there are 4 families of generalized cusps up to projective equivalence in dimension 3.