The Category P Features, Projections, Interpretation

(9) The main hypothesis
P is uniformly a functional category.
The realizations of P implicated by its functional classification are: (i) an
independent, phonetically full syntactic P-head; (ii) an affixal P, syntactically part of
the hosting head (it is affixed to); (iii) a phonetically null syntactic P-head consisting
of features.
Drawing on the variety of functions performed by each of the familiar functional
categories (e.g. C [-mod] introduces argumental clauses, C [+mod] heads predicative
(relative) clauses, Siloni 1997), I propose that P fulfills the following three roles
(functions) in syntax: P R(elation) , P C(ase) , and P pred(icate) . In this respect, it should be
emphasized that although the proposed roles of P are clearly distinguished, P R , P C ,
and P pred are subtypes of one functional category P, rather than three separate
syntactic categories.
The function of P R is to specify the relation of its complement to some other
entity (individual or event) (10). The particular semantic relation specified by P R (e.g.
location, cause, etc.) is determined by the meaning of the P-morpheme realizing P R :
(10) a. Dan found a coin in the garden.
b. Dan left because Mary was tired.
In light of the functional classification of P, although P R is assumed to be
interpreted as a predicate-argument function, it does not involve theta-assignment.
P C has a Case checking function, licensed (selected) by the corresponding lexical
head. It is carried out by a subset of Ps, which are assumed to be associated in the
lexicon with an uninterpretable set of φ-features, enabling them to check the Case
feature of a DP (11). In a variety of languages, including Hebrew and English, the
subset of Ps which realize P C consists of phonologically-small prepositions (e.g. in,
at), referred to descriptively as small Ps:
(11) a. Dan relies on his intuition.
b. Lisa believes in thinking.