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From: DSMITH@RUTGERS.ARPA
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Subject: Rutger's Computer Science Colloquium
Message-ID: <387@sri-arpa.UUCP>
Date: Tue, 27-Mar-84 14:22:39 EST
Article-I.D.: sri-arpa.387
Posted: Tue Mar 27 14:22:39 1984
Date-Received: Sun, 1-Apr-84 07:30:29 EST
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              [Forwarded from the Rutgers bboard by Laws@SRI-AI.]

                        Department of Computer Science

                                  COLLOQUIUM


SPEAKER:       Dr. Witold Lipski, Jr.
               Polish Academy of Sciences

TITLE:         LOGICAL PROBLEMS RELATED TO INCOMPLETE INFORMATION IN DATABASES


A  general methodology  for  modeling  incomplete  information in databases is
described, and then illustrated in the case of  three  concrete  models  of  a
database.   We emphasize the distinction between two different interpretations
of a query language --  the  external  interpretation,  which  refers  queries
directly  to  the  real world  modeled  by  the  database;  and  the  internal
interpretation, which refers queries  to  the  information  about  this  world
available  in  the  database.  Our methodology stresses the need for a precise
definition of the semantics of the query language by means of a non-procedural
specification,   and   for   a   correct   procedural implementation  of  this
specification.  Various logical -- and, at  times, combinatorial  --  problems
connected  with  information  incompleteness  are discussed.   Related work is
surveyed and an extensive bibliography is included.

DATE:           Friday, March 30, 1984
TIME:           2:50 p.m.
PLACE:          Room 705 - Hill Center
                                Coffee at 2:30