Sag&Wasow coordination question

[Lars G. Johnsen]

Hi all

I am using Sag&Wasow's book in a syntax course and have a question
concerning the coordination schema and its relation to unification. The
schema, in chapter 4, is formulated as:

[1] -> [1]+ CONJ [1]

There seems to be a problem with unification using this schema, or at
least it has caused me to scratch my head, but then i may have missed a
paragraph in the book. Here are two interpretations:

(1 - bottom up) The tag [1] means that the constituents in the
coordination must be unified with each other.
================

Problem: Given that constituents typically have a HEAD feature, the
schema (as it stands) will block any coordination of phrases with
conflicting agreement features (assuming these in the HEAD), something
we dont want in e.g. Norwegian, where NPs have gender agreement (a)
below, or in English with plurals (b):

 a) NP[+neut] CONJ NP[+masc].
 b) a man and two dogs entered


(2 - top down) The schema is interpreted as having instances like
follows:
================

[phrase HEAD noun] -> [phrase HEAD noun]+ CONJ [phrase HEAD noun]

These underspecified structures are then unified in turn with
constituents that make up the coordination, but constituents are not
unified with each other, so that examples (a-b) will be well formed
coordinations. This is almost the same as saying that coordination
extracts a common denominator from its constituents.

Problem: Under this interpretation, nothing prevents us (or so it seems)
from instantiating the schema as:

phrase -> phrase+ CONJ phrase

or

word -> word+ CONJ word

thus allowing *any* sequence of phrases or words to be coordinated,
which again is something we don't want.

Comments anyone?

Best, Lars G. Johnsen