<OT> New Posting: ROA-882

[roa at ruccs.rutgers.edu]

ROA 882-1106

No More than Necessary: beyond the 'four rules', and a bug report

Alan Prince <prince at ruccs.rutgers.edu>

Direct link: http://roa.rutgers.edu/view.php3?roa=882


Abstract:
After proposing four 'rules of inference' to be used
in the program OTSoft for simplifying collections of ranking
arguments, Hayes 1997 implicitly raises the question of
whether these rules suffice. In this note, the simplification
goal is spelled out within the analytical framework of Prince
2002a and Brasoveanu & Prince 2005, in prep. and the question
is settled (negatively). A generalization subsuming two
of Hayes’s rules is offered, however, and shown to provide
a complete solution to the simplification problem as formulated.
A tighter characterization of the role of disjunctive ranking
relations then follows.

Having rules of inference in hand is not the same as having
a procedure that uses them effectively. As of this writing,
the only known algorithm that produces a fully simplified
set of ranking conditions guaranteed to be both individually
necessary and jointly sufficient is Fusional Reduction (FRed),
presented in Brasoveanu & Prince (op. cit.), which relies
on different inferential assumptions.

Consequences for the use of OtSoft are noted. The typological
calculations and the stratified hierarchies produced in
response to a  ranking request are unchallenged. Those subparts
of the program which deal with the necessity of ranking
conditions (and concomitantly, necessary/non-necessary presence
of constraints) must however be used with circumspection
and should be supplemented with other methods. Some bugs
in this part of the program are reported.

Comments: 
Keywords: ranking conditions, necessary, sufficient, sofware, bug
Areas: Formal Analysis
Type: Manuscript

Direct link: http://roa.rutgers.edu/view.php3?roa=882