  The ordinary Bondi-Metzner-Sachs (BMS) group B is the common asymptotic
symmetry group of all asymptotically flat Lorentzian space-times. As such, B is
the best candidate for the universal symmetry group of General Relativity.
However, in studying quantum gravity, space-times with signatures other than
the usual Lorentzian one, and complex space-times, are frequently considered.
Generalisations of B appropriate to these other signatures have been defined
earlier. In particular, the generalisation HB, a BMS group appropriate to the
ultrahyperbolic signature (+,+,-,-), has been defined in a previous paper where
it was shown that all the strongly continuous unitary irreducible
representations (IRs) of HB can be obtained with the Wigner-Mackey's inducing
method and that all the little groups of HB are compact. Here we describe in
detail all the infinite little groups of HB and we find the IRs of HB induced
by them.
