[developers] ICONS and generation

[Woodley Packard]

I can confirm that under ACE, behavior is what you indicate, i.e. generating from parsing the topicalized feline-canine-playtime I get just the topicalized variant out, but when generating from parsing the ordinary word order I get all 5 variants out.

I believe this was designed to imitate the long-standing condition that the MRS of generation results must be subsumed by the input MRS.  The observed behavior seems to me to be the correct interpretation of the subsumption relation with ICONS involved.  Note that an MRS with an extra intersective modifier would also be subsumed, for example, but such MRS are never actually generated since those modifier lexical entries never make it into the chart.

It’s certainly reasonable to ask whether (this notion of) subsumption is really the right test.  I’ve met lots of folks who prefer to turn that subsumption test off entirely.  I guess it’s also possible that the subsumption test is right for the RELS portion of the MRS but not for the ICONS, though that seems a bit odd to consider.  However, given that we don’t have many ideas about truth-conditional implications of ICONS, maybe not so odd.

I don’t really have much to offer in terms of opinions about what the right behavior should be.  I (believe I) just implemented what others asked for a couple years ago :-)

-Woodley

> On Feb 5, 2016, at 8:03 AM, Ann Copestake <aac10 at cl.cam.ac.uk> wrote:
> 
> I'm part way through getting ICONS support working in Lisp, testing on the version of the ERG available as trunk. I have a question about generation.  If I implemented the behaviour described in http://moin.delph-in.net/IconsSpecs there doesn't seem to be a way of specifying that I want a `normal' ordering for English.
> 
> e.g., if I take the MRS resulting from
> 
> that dog, the cat chased.
> 
> without ICONS check, there are 5 realizations, including the `null ICONS' case `The cat chased that dog.'  With an exact ICONS check, I can select realizations with the same ICONS (modulo order of ICONS elements, of course, in the case where there's more than one element).  But with the http://moin.delph-in.net/IconsSpecs behaviour, there's no way of specifying I want a `normal' order - if I don't give an ICONS, I will always get the 5 realisations. In fact, as I understand it, I can always end up with more icons in the realisation than in the input, as long as I can match the ones in the input.
> 
> So:
> - is the IConsSpec behaviour what is desired for the ERG (e.g., because one can rely on the realisation ranking to prefer the most `normal' order)?
> - or does the ERG behave differently from Emily and Sanghoun's grammars, such that different generator behaviour is desirable? and if so, could we change things so we don't need different behaviours
> 
> Ann
> 
> 
>