Figure heads in HPSG

Figure heads are words without autonomous content, such as t he copula and the infinitival to. They pose a challenge for the head-driven semantics of HPSG -94, since the latter requires the CONTENTjNUCLEUS value of ahead-complement combination to be identical to the one of its head daughter. As a consequence, if the head i s semantically vacuous, the combination is —erroneously— predicted to be vacuous as wel l. In order to repair this, HPSG-94 stipulates that the CONTENT value of a vacuous word i s i entified with the one of its complement. Technically, this gives the right result , but it leaves a number of issues unresolved. First, if the copula is vacuous, then what happe ns to the semantic contribution of its tense? Second, what are the criteria for identifying v acuous words? Third, are there any alternatives for the figure head treatment, and if so, wha t is the kind of evidence that can be used to motivate a choice? In dealing with these questi ons, I will integrate a DRT style treatment of the tenses in the HPSG framework (section 3), I will define a number of criteria for identifying vacuous verbs (section 4) and I wil l provide some empirical evidence against the figure head treatment, replacing it with an alter native analysis in which vacuous verbs have no CONTENT feature at all (section 5).