On Canonical Threefolds

Abstract

In a paper which is to be published shortly formulae have been obtained for the virtual characters of the system of surfaces cut out on a primal of S4, having ordinary singularities, by adjoint primals of any order; an account of the principal results has been given elsewhere. As a first application of these formulae we propose in the present paper to investigate the canonical systems belonging to various threefolds and thence to construct the canonical models which correspond to them.