The Flipped SU(5) model is a GUT theory which states that the gauge group is [ SU(5) x U(1) ]/ and the fermions form three families, each consisting of the representations , 10-1 and 1-5. This includes right-handed neutrinos, which are known to exist because of observed neutrino oscillations. There is also an adjoint scalar field, a 10-1 and/or called the Higgs field which acquires a VEV. This results in a spontaneous symmetry breaking from
to
and also,
, , , .

Of course, calling the representations things like and 240 is purely a physicist's convention, not a mathematician's convention, where representations are either labelled by Young tableaux or Dynkin diagrams with numbers on their vertices, but still, it is standard among GUT theorists.

Since the homotopy group

this model no predicts monopoles. See Hooft-Polyakov monopole.

To do:

This theory was invented by ???.