In this paper we define a new clausal class, called
$
\mathcal{B}\mathcal{U}
$
\mathcal{B}\mathcal{U}
, which can be decided by hyperresolution with splitting. We also consider the model generation problem for
$
\mathcal{B}\mathcal{U}
$
\mathcal{B}\mathcal{U}
and show that hyperresolution plus splitting can also be used as a Herbrand model generation procedure for
$
\mathcal{B}\mathcal{U}
$
\mathcal{B}\mathcal{U}
and, furthermore, that the addition of a local minimality test allows us to generate only minimal Herbrand models for clause
sets in
$
\mathcal{B}\mathcal{U}
$
\mathcal{B}\mathcal{U}
. In addition, we investigate the relationship of
$
\mathcal{B}\mathcal{U}
$
\mathcal{B}\mathcal{U}
to other solvable classes.
We thank the referees for helpful comments and suggestions. The work is supported by research grants GR/M36700 and GR/R92035
from the EPSRC, UK.