<OT> Re: Quadratic Alignment Constrants and Finite State Optimality Theory

[Biro Tamas]

Dear Jason Eisner,


I am thankful for all the remarks you made, and I wish I had known 
earlier and better your work.

I hope that ROA and OT-list are as useful for all of its members as 
it has been for me. For it is thanks to them that I received your 
reaction to my work.

I would be thankful if you sent me in private the proof you 
"suppressed for reasons of space" from your ACL 97 paper.

Best,


Tamas



On Thursday 22 May 2003 09:09, Jason Eisner wrote:
> > Quadratic Alignment Constraints and Finite State Optimality
> > Theory Tamás Bíró <birot@let.rug.nl>
> > Direct link: http://roa.rutgers.edu/view.php3?roa=600
>
> Hi Tamás,
>
> I don't usually plug my work on this list, but I'm afraid it's not
> a new observation that GA constraints count up quadratically many
> violations, or that this is beyond the ability of finite-state
> devices.  See section 4.1 of Eisner 1997 (ACL).
>
> Your paper also says that "future work" should prove that the
> ranking or filtering effect of a quadratic GA constraint cannot be
> achieved by some other finite-state device.  This too was shown in
> the above reference; write to me for full proof details.
>
> Note that a quadratic number of violations is not by itself a
> problem. Consider the hypothetical constraint "NoCodaSquared,"
> which assigns n*n violations to a candidate with n codas.  This has
> a quadratic number of violations, but imposes exactly the same
> ranking on candidates as NoCoda does.  So its effect can be
> captured just as well by a transducer that counts linearly 1,2,3
> ... (or 2,4,6 ...) instead of quadratically 1,4,9 ...
>
> In the same way, most phonologists use quadratic GA constraints
> only to do work that could also be done by harmless finite-state
> devices. Not surprising, since they're describing phonologies.  But
> the GA mechanism unfortunately does have more power -- it can be
> used to describe linguistically unattested, computationally
> non-finite-state phenomena.
>
> It was to respond to this concern that I developed a completely
> GA-free, finite-state OT account of metrical stress typology (also
> in 1997).
>
> As you seem to be interested in cutting back OT's power to that of
> regular relations, you might also look at papers that I wrote in
> 2000 and 2002.  Particularly the work on directional constraint
> evaluation. Quadratic constraints (as you note) prevent you from
> using an FST to count violations.  Even linear constraints (as
> Frank & Satta noted) are powerful enough to prevent you from using
> an FST to map between underlying and surface forms.  Directional
> constraint evaluation neatly eliminates both problems, thereby
> improving OT's explanatory adequacy -- while apparently retaining
> descriptive adequacy.
>
> Best place to get any of these papers is
>    http://cs.jhu.edu/~jason/papers/narrative.html#sec-ot
> although some are also on the ROA.
>
> cheers,
> jason eisner (johns hopkins univ.)
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-- 

   ----------------------------------
| Tamas Biro:     birot@nytud.hu
|                      birot@let.rug.nl