[developers] Lexical rules changing predicate symbols

[Ann Copestake]

Yes, I would be happy with that, except that I would suggest making use 
of meaningful sense labels, at least as a mnemonic.  So the pattern on 
the rule would be

_P_v_dance (e,x) <- LR ->  _P_n_dance (x)

The one could apply the rule productively, by specifying the appropriate 
verbs as having predicates of the form _v_dance, if one wanted.  (The 
alternative is to just use the rule as a description and explicitly 
state what it applies to, but since one could control the application 
via an inventory of sense labels if the predicate is decomposed and the 
senses correspond to types, I think this is effectively equivalent.)

What I would ideally want to say about  the _dance_ component of the 
predicate is that one should take it as commiting to the lexeme implying 
dance when making inferences about the real world.  I'm deliberately 
stating this informally because what this actually means is up to the 
grammar writer, but I would take it as allowing that inference to be 
made by a computational system (using a robust notion of inference!).  
This certainly does not commit one to saying that all lexemes denoting 
dances will have this sense.

For a language like Lushootseed this might not be enough to capture the 
way that nouns and verbs behave, but at least it is a start.

For what it's worth, I think of _tango_v_dance as corresponding to a 
semantic space which is close to _tango_n_dance on most dimensions, but 
shifted corresponding to the verb/noun shift.  (There's been a little 
experimental exploration of this sort of thing in distributional 
semantics - there could be much more - but I'm talking about some sort 
of idealised space now.  What Aurelie and I have called `ideal 
distributions' would work here.)  In this idealized space, these are 
subspaces of the dance n and v spaces. And, for that matter 
_tango_*_dance (where * generalises over n/v) has _tango_n_dance and 
_tango_v_dance as subspaces, and so on.

Going back to what I was saying before, if one thinks there's a meaning 
postulate that expresses the relationship between the verbal and nominal 
form - e.g., something of the form:

forall x,e [ _tango_v_dance (e,x) <=> exists y [ _dance(y) & 
PERFORM(e,x,y) ]]]

or whatever, where I'm using PERFORM as a placeholder, then the 
alternative would be to express that in the lexical rule and not have a 
separate predicate for the nominal sense.  But then one would have to 
work out a story about what the precise nature of the relationship 
PERFORM (or whatever) is, and whether this can be expressed in terms of 
properly motivated semantic predicates like Dowty's DO, CAUSE and so 
on.  Saying that there are related semantic spaces is actually 
compatible with this but much more general - obviously it's very vague, 
unless one starts to additionally express constraints on the 
relationship between the semantic spaces. But my own feeling is that 
doing these semantic relationships by hand/symbolically is a dead-end 
(because there's lots of different ones, and they have nuances and 
exceptions and so on).
The alternative approach of using systematic naming conventions for the 
predicates allows us to make the connection explicitly visible to some 
distributional component, without commiting to the actual lexical semantics.

All best,

Ann

On 17/09/2016 05:29, Emily M. Bender wrote:
> Thank you for this follow up, Ann. I think I understand your view of 
> things.  Just one piece
> I wanted to follow up on this evening:
>
>
>     On the other hand, as you said, there are other processes where
>     the pattern is regular but with some exceptions, and where the
>     precise semantic effect is difficult to pin down.  Much of English
>     derivational morphology falls into this class - it is useful to
>     represent the relationship with the stem somehow, without claiming
>     that we're capturing everything there is to say.  e.g., "unkind"
>     definitely has some relationship with (a sense of) "kind", and
>     it's useful to know about that, but there are some idiosyncratic
>     aspects of its meaning.   Similarly, I'd say it's useful to
>     represent the relationship between nouns denoting dances and the
>     corresponding verbs (tango etc), which is productive, but I'm
>     quite content to do that via a predicate changing operation.
>
>
> As I currently understand things, the change in the predicate symbol 
> from _tango_n_1
> to _tango_v_1 would correlate with:
>
> (1) Change of type of ARG0 from x to e
> (2) Addition of ARG1 (of type x)
>
> ... or in the other direction:
>
> (1) Change of type of ARG0 from e to x
> (2) Removal of ARG1
>
> In other words, I think the predicate changing operation would also 
> have concomittant
> changes elsewhere in the EP.  Also okay?  (This has implications, btw, 
> for the analysis
> of Lushootseed that Joshua is working on, where there are lots of 
> stems that seem to
> be happy to serve as either nouns or verbs.)
>
> Emily
>
>
>
> -- 
> Emily M. Bender
> Professor, Department of Linguistics
> Check out CLMS on facebook! http://www.facebook.com/uwclma

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