My question is probing to learn whether semanticists (and syntacticians) draw a distinction between what I am calling here semantic and syntactic predicates. The question concerns the status of the NP a politician in the following examples:
a. Bill is a politician. b. Bill, a politician, is pandering. c. A politician (I know) is pandering.
In (a), the predicative NP a politician is a property that is predicated of Bill. In (b), the appositive NP a politician is again a property that is also predicated of Bill. In (c) in contrast, one cannot view a politician as being predicated of another part of the sentence. What seems to be occurring, rather, is that a politican in (c) is being predicated of a discourse entity, i.e. of someone in the discourse context. The predicate-calculus-style representations for these sentences might be as follows:
a'. is a politician (Bill) b'. is pandering (a politician (Bill)) c'. is pandering (a politician)
In (a'-b'), a politician can be viewed as a predicate in every sense. In (c'), in contrast, a politician is not a predicate insofar as it is not predicated of another part of the sentence. For the sake of putting names on the distinction, a politician is both a semantic and syntactic predicate in (1a-b), but it is only a semantic predicate in (c'); it is not a syntactic predicate in (c').
The terminology I have just used is unique to my understanding. What I would like to find out is whether there is already an established terminology for this distinction. Note that the distinction in predicate types is important for predicting the distrubtion of, for instance, reflexive pronouns (e.g. Susan likes our picture of herself vs. *Susan said that we like herself) and negative polarity items (e.g. The discussion of no problem did anyone find interesting vs. *Discussing no problem did anyone find interesting). The distribution of these items is sensitive to the difference in predicate types.