Newsgroups: comp.ai.jair.announce
Path: cantaloupe.srv.cs.cmu.edu!bb3.andrew.cmu.edu!newsfeed.pitt.edu!godot.cc.duq.edu!newsgate.duke.edu!zombie.ncsc.mil!news.mathworks.com!newsfeed.internetmci.com!news.msfc.nasa.gov!pendragon!ames!eos!kronos.arc.nasa.gov!jair-ed
From: jair-ed@ptolemy.arc.nasa.gov
Subject: New Article, Least Generalizations and Greatest ...
Message-ID: <1996May24.000650.22123@ptolemy-ethernet.arc.nasa.gov>
Originator: jair-ed@polya.arc.nasa.gov
Lines: 40
Sender: usenet@ptolemy-ethernet.arc.nasa.gov (usenet@ptolemy.arc.nasa.gov)
Nntp-Posting-Host: polya.arc.nasa.gov
Organization: NASA/ARC Computational Sciences Division
Date: Fri, 24 May 1996 00:06:50 GMT
Approved: jair-ed@ptolemy.arc.nasa.gov

JAIR is pleased to announce the publication of the following article:

Nienhuys-Cheng, S.H. and de Wolf, R. (1996)
  "Least Generalizations and Greatest Specializations of Sets of Clauses", 
   Volume 4, pages 341-363.

   Available in Postscript (281K) and compressed Postscript (109K).
   For quick access via your WWW browser, use this URL:
     http://www.cs.washington.edu/research/jair/abstracts/cheng96a.html
   More detailed instructions are below.

   Abstract: The main operations in Inductive Logic Programming (ILP) are
   generalization and specialization, which only make sense in a
   generality order.  In ILP, the three most important generality orders
   are subsumption, implication and implication relative to background
   knowledge.  The two languages used most often are languages of clauses
   and languages of only Horn clauses. This gives a total of six
   different ordered languages.  In this paper, we give a systematic
   treatment of the existence or non-existence of least generalizations
   and greatest specializations of finite sets of clauses in each of
   these six ordered sets.  We survey results already obtained by others
   and also contribute some answers of our own.
   
   Our main new results are, firstly, the existence of a computable least
   generalization under implication of every finite set of clauses
   containing at least one non-tautologous function-free clause (among
   other, not necessarily function-free clauses).  Secondly, we show that
   such a least generalization need not exist under relative implication,
   not even if both the set that is to be generalized and the background
   knowledge are function-free.  Thirdly, we give a complete discussion
   of existence and non-existence of greatest specializations in each of
   the six ordered languages.

The article is available via:
   
 -- comp.ai.jair.papers (also see comp.ai.jair.announce)

 -- World Wide Web: The URL for our World Wide Web server is
       http://www.cs.washington.edu/research/jair/home.html
    For direct access to this article and related files try:
       http://www.cs.washington.edu/research/jair/abstracts/cheng96a.html

 -- Anonymous FTP from either of the two sites below.

    Carnegie-Mellon University (USA):
	ftp://p.gp.cs.cmu.edu/usr/jair/pub/volume4/cheng96a.ps
    The University of Genoa (Italy):
	ftp://ftp.mrg.dist.unige.it/pub/jair/pub/volume4/cheng96a.ps

    The compressed PostScript file is named cheng96a.ps.Z (109K)

 -- automated email. Send mail to jair@cs.cmu.edu or jair@ftp.mrg.dist.unige.it
    with the subject AUTORESPOND and our automailer will respond. To
    get the Postscript file, use the message body GET volume4/cheng96a.ps 
    (Note: Your mailer might find this file too large to handle.) 
    Only one can file be requested in each message.

 -- JAIR Gopher server: At p.gp.cs.cmu.edu, port 70. 

For more information about JAIR, visit our WWW or FTP sites, or
send electronic mail to jair@cs.cmu.edu with the subject AUTORESPOND
and the message body HELP, or contact jair-ed@ptolemy.arc.nasa.gov.



