[lkb] Generator question

[Emily M. Bender]

Yes, thanks.  We will reorganize our feature structures then.

Emily

On Wed, Mar 28, 2007 at 09:11:16PM -0800, Stephan Oepen wrote:
> hi emily,
> 
> > This seems to be a problem for the generator: So long as cog-st is a
> > sort (no features), the cog-st value is respected in generation. As 
> > soon as we add the feature SPECI, however, the generator will ignore 
> > the type of the COG-ST value.
> 
> i think your problem is strictly speaking not about the generator.  it
> is important to acknowledge the difference between the grammar-internal
> universe of typed feature structures and the grammar-independent world
> of MRSs.  MRSs are not typed in a very interesting sense, and they have
> very little accomodation for embedding of structures (i.e. recursion).
> 
> a typed feature structure
> 
>   ref-index & [ COG-ST foo ]
> 
> may correspond to an MRS variable, say,
> 
>   x42 { COG-ST: foo }
> 
> for convenience, MRS variables can have internal properties, but their
> values are constrained to be atomic.  hence,
> 
>   ref-index & [ COG-ST foo & [ SPECI + ] ]
> 
> converts into
> 
>   x42 { COG-ST.SPECI + }
> 
> the process of constructing an MRS from its FS description, helpfully,
> flattens out embedded structures and creates property names from paths
> of feature names.  hence, even though `COG-ST.SPECI' looks a lot like
> the TDL path notation, in the MRS universe it is a plain symbol, viz.
> the name of that property.  there is no room for the sortal constraint
> `foo' from the midst of the underlying path in that representation.
> 
>                 i hope this helps clarify the issue?  all best  -  oe
> 
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