Newsgroups: ont.events
Path: utzoo!utgpu!jarvis.csri.toronto.edu!bloor.csri!diana
From: diana@csri.toronto.edu (Diana Li)
Subject: U of TORONTO SEMINAR NOTICE 
Message-ID: <1989Jun13.120426.15966@jarvis.csri.toronto.edu>
Organization: University of Toronto, CSRI
Distribution: ont

Keywords:    SYSTEMS SEMINAR
Room:        SF 4103 
Time:        11:00 a.m.
Day:         Thursday 22 June 1989
Speaker:     Jan Chomicki
Affiliation: University of Maryland
Topic:       "Every other day": infinite query answers in logic programming 


We present here the case for a new approach to database applications
of logic programming.  Better computational properties of logic
programs can be achieved if the occurrences of function symbols in
rules are restricted.

We define the class of FUNCTIONAL logic programs where function
symbols can only appear in one distinguished position in every
predicate.  Additionally, the arity and type of function symbols are
restricted.  This class is known to be decidable.  Functional logic
programs are capable of representing infinite phenomena like the flow
of time and may be used for the construction of intelligent office
tools (e.g. an event scheduler).

We study the problem of processing queries to functional programs.  In
particular, query answers may be infinite.  We present a method to
finitely represent such answers as relational specifications
consisting of a finite set of tuples and a finitely specified
congruence relation. We also discuss the applications, possible
extensions and limitations of our approach, and relate it to other
work on intensional query answers.

\fI(This notice supersedes an earlier announcement in which the date 
was wrongly typed as Friday 2 June.)\fR