[developers] Trigger rules with specialization

Woodley Packard sweaglesw at sweaglesw.org
Sun Dec 11 17:20:46 CET 2011

Hi Francis,

When does the information that distinguishes the two classes of  
adjectives become accessible?  It sounds like you would like to  
trigger "darou-v-cop-lex" when there is a na-adjective present, and  
not trigger it when there is not a na-adjective present.  If there is  
no information distinguishing these two types of adjectives in the  
MRS, I don't think my extension would help; it would allow the  
specification of constraints on the *triggered* lexeme's AVM, not on  
the AVMs of signs that are instantiated to match the context list  
(which could be confusing, given the potentially many-to-many mapping  
between EPs and signs).  It could in principal be used to reduce the  
situations in which the trigger rule matched (via failed unification  
of those constraints), but I would expect the more useful effect to be  
the presence of those additional constraints on that triggered lexeme  
in the chart, reducing its rampant combinatorics.

Here's another example in English.  When I parse "I think that the dog  
barks." and generate from the resulting MRS, the complementizer  
"that" (and also "like", "as if" and "as though") are triggered.  They  
are needed in the chart (obviously) so that they can combine with the  
"the dog barks" clause, but there is no way to specify that they can  
*only* combine with that clause.  As a result, we get edges in the  
generator chart that look like "that I think", "that I think the dog  
barks", and "that I think that the dog barks" (and many other  
combinations).  These are wasted computation.  With the proposal, the  
trigger rule could skolemize the complementizer's  
COMPS.FIRST.SYNSEM.LOCAL.CONT.HOOK directly (or something similar).   
The combinatorics caused by this example in English are noticeable but  
not too bad; I understand it is worse in the Wambaya and German  
problem cases.


On Dec 11, 2011, at 6:09 AM, Francis Bond wrote:

> G'day,
> we have a slightly related issue in Jacy where the semantics doesn't
> constrain things enough.  In the most clear case there are two kinds
> of adjectives, one which inflects, and one which needs a separate
> inflecting word.  There is nothing in the semantics that distinguishes
> between these two.
> We are currently over-inserting using regexps as in:
> darou-cop-lex_gr := arg0e_gr &
> [ CONTEXT [ RELS <! [ PRED "~_a_"] !> ],
> FLAGS.TRIGGER "darou-v-cop-lex" ].
> This has the unfortunate effect that it triggers on all adjectives,
> when we really only want one class of adjectives (na-adjectives).
> If I understand it correctly, your extension would allow us to trigger
> much more appropriately.
> -- 
> Francis Bond <http://www3.ntu.edu.sg/home/fcbond/>
> Division of Linguistics and Multilingual Studies
> Nanyang Technological University

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