Filler-gap mismatches

[Carl Pollard]

>
The idea of putting just the part-of-speech in the f-structure and not
the bar-level does remove conflicts that would otherwise appear up a
single head chain, but it still eliminates some of the descriptive and
explanatory advantages of the current set up.  For example, we can
account for constructions such as gerunds that have a mixture of
properties that are normally associated with different parts of speech
by saying that nodes of the different part-of-speech (ignoring
bar-level) types map to the same f-structure, in effect, that the
c-structure nodes are co-heads of the functional units.  (I think Joan
and others have written about this).
>>

Of course HPSG has analyses of gerunds (several different ones, in
fact), but they are not like the kind of analysis you just described).

>
A significant point about descriptions through inverse correspondences
is that the induced properties (f-category, f-precedence) are
degraded, less informative versions of the related properties in
c-structure.  The inverse correspondence fuzzes things up a bit,
because the forward correspondence is not one-to-one and not onto.  We
claim that the induced fuzziness is just what you need to naturally
characterize different kinds of phenomena.  Now, you could get the
same effect by saying that a part-of-speech attribute in the
f-structure is not filled by a single category symbol but rather by a
set of categories, and then various mixture properties could be
enforced by testing for one or another element of the set.  But that
would be a pure stipulation independent of anything else in the formal
system; doing it not by copying but by making information accessible
looking backwards makes for a stronger and more natural set of claims.
>>

I think I ned an example to get the gist of the preceding passage.

>
But even if we were to make the move of copying part-of-speech
categories,
>>

I wasn't really suggesting copying the part of speech, but just
not having it in c-structure at all.

>
I'm not sure that the HEAD and ARG-STRUC combination would
then correspond directly to what we have in f-structure, although I
agree they would be more similar.  (It may be that I don't understand
exactly what you (or the correct theorists) code in those features).
The LFG f-structure has features like tense and case, and also modifiers
like adjuncts, which are not strictly speaking arguments (probably the
opening gambit of another long discussion).  Does ARG-ST also include
adjuncts and other kinds of features?
>>

On the Bouma-Malouf-Sag view, many adjuncts DO show up in ARG-ST.
CASE is in HEAD. For English, TENSE has not usually been treated as
syntactic feature, though VFORM (with values like finite, base, infinitive,
etc.) is in HEAD.

>
Another historical note:  again in the mid 70's I also included
arguments in the feature structure under special attributes like ARG1,
ARG2, so that everything would be in a single representation.  But again
that was abandoned, mostly in the interests of modularity.  We wanted to
have a representation for syntactic properties that encoded only the
semantic information that interacted with other syntactic features and
was a sufficient basis for later full-scale semantic interpretation.
The PRED semantic-forms carry the minimal set of properties:  the
semantic arity, the mapping of arguments to grammatical functions, and
the instantiation of individuals.  This is sufficient, we suggested, for
working out a lot of syntactic stuff and for many syntax/semantics
interactions, but without committing to any particular theory of
semantic representation or semantic interpretation (the "glue" semantics
now gives us a theory of interpretation, but even it can still leave
open the question of representation--modularity strikes again).
>>

I wasn't clear whether in the preceding passage `arguments' meant
syntactic ones or semantic ones.

>
The argument list in a semantic form may be the thing that corresponds
directly to your ARG-ST--and it is typically represented as an ordered
sequence, which might meet one of Berthold's reservations.
>>

No, I think that is more analogous to the stuff in the HPSG CONTENT
value, and that ARG-ST is pretty much analogous to the f-structure
attributes that talk about dependents: SUBJ, OBJ, ADJUNCTS, etc.

>
But I don't think we have the worry about composition of ARG-ST values
on the mother of coordination, the point from the thread a few months
ago.  (Indeed, I don't think most LFG people would understand what the
problem was that that discussion was all about--we were going to have
a little study group at Parc to go over all the messages and see if we
could map any of the issues onto problems in LFG.)
>>

I think in both LFG and HPSG the answer is roughly that the feature
structure (f-structure for LFG, category for HPSG) of a coordinate
structure is the set of categories of the conjuncts. Or at least
the analog of `set' in some interpretation of higher-order logic.
(For them to LITERALLY be sets would mean that the interpretation
of the grammar logic was a Henkin model, but that is another story.)


Carl