Notes on computational linguistics.pdf - UCLA Department of ...

18 Some open (mainly) formal questions about language
Quite a few problems that do not look like they should be very difficult remain open, and we have come up
against many of them in this class. I expect these problems to be addressed and some of them settled in the next
few years. A few of these were decided in the last year, and I show (conjectures that changed from last year).
Empirical difficulty estimate E from 1-10,
where 0 is the difficulty of questions like “How tall is Stabler?”
and 10 is “What language analysis goes on when you read this?” or “How long ago was the big bang?”
Formal difficulty estimate F from 1-10,
where 0 is the difficulty of questions like “Is a n b n a regular language?”
and 10 is deciding Poincaré’s conjecture or P=NP or the Riemann hypothesis.
E F
0 2 Are “minimalist languages” (MLs) closed under intersection with regular languages? yes
And are MLs = MCTALs? (Harkema, Michaelis 2001) yes
0 2 Letting UMLs be languages defined by minimalist grammars where the
features of each lexical item are unordered (Chomsky, 1995) UMLs=MLs? (yes?)
? 2 What dimension (=how many moving components) do “minimalist grammars”
for human languages require? (?)
0 2 What automata recognize exactly the MLs? (Wartena, 1999) (?)
Do they allow tabular recognition methods with the correct prefix property? (Harkema 2001) yes
? 2 How should MGs be extended to handle deletions? suffixaufnahme? (?)
rigid MGs can be identified from a certain kind of dependency-structure (Stabler, 2002).
0 2 Are rigid MGs PAC-learnable from d-structures (or “simple” distributions of them)? (yes?)
2 0 Can language learners recognize the dependencies encoded in the d-structures? (?)
0 2 Is the onset constraint of (Prince and Smolensky, 1993, §6), when formulated
as a function from inputs to optimal structures as in (Frank and Satta, 1998),
a finite transduction? (yes?)
? 2 Are the contraints of OT phonology “local” in the sense that
there is a principled finite bound k such that, when each constraint
is formulated as a function from candidates to numbers of violations,
it is defined by a finite transducer with k or fewer states? (yes?)
? 2 Are the contraints of OT phonology “local” in the sense that
there is a principled finite bound k such that, when each constraint
is formulated as a function from candidates to numbers of violations,
it is defined by a finite transducer that is k-Markovian?
(i.e. transducer state is determined by last k input symbols) (yes?)
2 2 Can reduplication be factored out of phonology elegantly, to allow local
application of correspondence theory constraints? (no?)
2 2 What automata are most appropriate for recognizing reduplication? (?)
Does it allow tabular recognition methods with the correct prefix property? (Albro 2002) yes
0 2 Are OT grammars in the sense of (Tesar and Smolensky, 2000) or (Hayes and Boersma, 2001)
efficiently PAC-learnable in the sense of (Kearns and Vazirani, 1994) or (Li and Vitányi, 1991) (no?)
? ? Why are the most frequently occurring lexical items “grammatical morphemes”? (?)
? ? Why are about 37% of word occurrences nouns?
(in most discourses, in English, Swedish, Greek, Welsh – Hudson 1994) (?)