The N-quantum approximation, concrete composite models of quarks and leptons, and problems with the normalization of composite massless bound states

The authors discuss concrete composite models of quarks and leptons using the N-quantum approximation. The first section introduces the main ideas of this approximation, the second section describes the bound-state equations which follow when chiral symmetry is assumed to hold in the Wigner-Weyl mode so that the fermions of the theory, both elementary and composite, have zero mass, and the third section points out a problem with the normalization of composite zero-mass bound states, and offers a suggestion to resolve the problem