In this section, we present the basics of our analysis of German verb clusters. The analysis of word order is presented in section 5.
Following the analysis of German modal and auxiliary verbs given in , we assume that modals and auxiliaries are so-called `argument-inheritance' verbs, which select for a list of complements consisting of a verb and the complements selected by that verb:
The verbs helfen (to help) and lassen (to let) are analyzed as argument-inheritance verbs as well. Note that these verbs also select an NP object:
We make the additional assumption that argument-inheritance verbs require a verbal complement that is of type word. Since the verbal complement cannot be a (complex) phrase, a consequence of this requirement is that an argument-inheritance verb necessarily inherits all complements of its verbal complement. This not only prevents spurious ambiguity, but, as we will see below, is also crucial for our account of word order.
The following, general, HEAD-COMPLEMENT schema is used to derive `flat' verb phrases:
This schema states that a mother node dominates a lexical head daughter H, with an arbitrary number of daughters to the left and to the right of H.2All non-head daughters are complements. The value of L, R, and COMPS on the mother is determined by the following constraint:
Thus, (4) can be used to form both partial and saturated verb-phrases. Note, however, that since the head must be a word, a phrase derived by means of the schema in (4) cannot be the head of a larger HEAD-COMPLEMENT structure. In this paper, we will not make use of partial VP's, but in  we argue that the interaction of (4) and (5) enables an account of partial VP fronting as well as partial VP extraposition. Other constraints applying to the HEAD-COMPLEMENT schema are the HEAD-FEATURE and NONLOCAL FEATURE principles of  and the word order constraints introduced below.
The schema in (4) and the lexical entries for argument inheritance verbs together give rise to derivations of subordinate clauses in which a lexical head directly combines with all of its complements. Thus, there is no phrase corresponding to the verb cluster, nor any other internal phrase structure in the VP: 3
Since the HEAD-COMPLEMENT schema requires a lexical head, and the argument-inheritance verbs haben and helfen require a lexical verbal complement, the `flat' derivation is the only one possible according to the grammar, ignoring word order variation for the moment.
In the remainder of this paper, we will be concerned with the question how to account for word order in VP's containing one or more argument-inheritance verbs. We will provide word order constraints which, in conjunction with the HEAD-COMPLEMENT schema in (4), account for the German nested dependency word order, as well as Oberfeldumstellung and Zwischenstellung word orders. Before doing so, however, we will first review previous proposals.