  The material below the crust of a neutron star is understood to be
describable in terms of three principal independently moving constituents,
identifiable as neutrons, protons, and electrons, of which the first two are
believed to form mutually coupled bosonic condensates. The large scale
comportment of such a system will be that of a positively charged
superconducting superfluid in a negatively charged ``normal'' fluid background.
As a contribution to the development of the theory of such a system, the
present work shows how, subject to neglect of dissipative effects, it is
possible to set up an elegant category of simplified but fully relativistic
three-constituent superconducting superfluid models whose purpose is to provide
realistic approximations for cases in which a strictly conservative treatment
is sufficient. A "mesoscopic" model, describing the fluid between the vortices,
is constructed, as well as a "macroscopic" model taking into account the
average effect of quantised vortices.
