HPSG and GPSG

[Detmar Meurers]

Hi Howard and list members,

>  I was assuming an HPSG that was tied to  phrase structure rules, as in the
>  presentation in (most of) SWB. In this case, I understand that the
>  relationship with indexed grammars holds (or  has been argued to hold). You
>  would still not get CFG's, as you point out, unless the other recursive data
>  structures were restricted to finite depth. (Is it the case that one would
>  have to eliminate them entirely?)

I'm not aware of a formalization of HPSG based on phrase structure
rules for which it has been claimed that it is equivalent to indexed
grammars. If you could send me a pointer I can try to follow up on
that off-list.

>  I guess the relationship between this and the HPSG formalism not tied to
>  phrase structure rules is analogous to that between DCG's and Colmerauer's
>  Metamorphosis Grammars. (From which you can take it that I am looking at these
>  issues partly from the point of view of implementing of HPSG grammars as
>  DCG's.)

For a discussion of different ways to map HPSG theories to
implementations with or without a phrase structure (backbone), check out

- Detmar Meurers (1994). On Implementing an HPSG theory: Aspects of
  the logical architecture, the formalization and the implementation
  of head-driven phrase structure grammars.
  http://www.ling.ohio-state.edu/~dm/on-implementing.html

>  Perhaps you could suggest where I could read up on the formal properties of
>  HPSG grammars whose treatments of word order are not tied to phrase structure
>  (Reape, Kathol etc).

Linearization-based HPSG grammars can be expressed in King's SRL as
a formal foundation for HPSG - this is discussed in:

- Frank Richter & Manfred Sailer (1995): Remarks on Linearization.
  Reflections on the treatment of LP-rules in HPSG in a typed
  feature logic.
  http://www.sfs.uni-tuebingen.de/~fr/cards/thesis.html

Or a more general discussion:

- Frank Richter (2000): A Mathematical Formalism for Linguistic
  Theories with an Application in Head-Driven Phrase Structure Grammar
  Doctoral dissertation.
  http://www.sfs.uni-tuebingen.de/~fr/cards/dissertation.html

For a specialized grammar formalism that defines a backbone for
parsing with linearization-based HPSG grammars, you might want to
check out the work on Generalized ID/LP grammars that Mike Daniels
and I have been doing recently:

- Mike Daniels and Detmar Meurers (to appear): 'GIDLP: A Grammar
  Format for Linearization-Based HPSG'. Proceedings of the Eleventh
  Int. Conference on HPSG. Leuven.

- Mike Daniels and Detmar Meurers (to appear): `A grammar formalism
  and parser for linearization-based HPSG'. Proceedings of the 20th
  International Conference on Computational Linguistics (COLING
  2004). Geneva.

Send me a message if you're interested in a copy- I'll add
electronic versions of those to my web page in the near future.

Lieben Gruß,
Detmar

--
Detmar Meurers, Assistant Professor, Dept. of Linguistics, OSU
201a Oxley Hall, 1712 Neil Avenue, Columbus OH 43210-1298, USA
http://ling.osu.edu/~dm/                 GnuPG key on web page