The content of a noun is represented in HPSG by a feature structure of type nom-obj, which is structured as in hpsg1.
The index value is a reference marker, to which semantic roles
are assigned. The restriction attribute specifies any semantic
restrictions on the referent of the noun. These restrictions are in
the form of parametrised states of affairs (psoas) which convey
relations between referential indices and/or other psoas.
Different relations are realised as subsorts of the type qfpsoa
(quantifier-free psoa). These subsorts are defined for
particular numbers and types of arguments. Following Situation
Semantics (Barwise and Perry barwise_perry:83), which provided the inspiration for
the HPSG notion of psoas, qfpsoa relations are basic,
corresponding to individuations of relations in the world made by
cognitive agents. I will discuss the relations utilised in HPSG in
further detail below.