  We present a non-perturbative lattice study of SU(4) gauge theory with two
flavors of fermions in the fundamental representation and two in the two-index
antisymmetric representation: a theory closely related to a minimal
partial-compositeness model for physics beyond the Standard Model, that was
proposed by G. Ferretti. We discuss the phase structure of the lattice theory
and report results for various observables of interest, including the masses of
states obtained from different combinations of valence fermions and the
spectrum of the Dirac operator. Finally, we comment on the extension of this
type of studies to other partial-compositeness models (including, in
particular, one that was recently suggested by H. Gertov et al.), which could
admit lighter top-quark partners, highlighting some key features of our lattice
simulation algorithm, that make it suitable for such generalizations.
