Newsgroups: ont.events
Path: utzoo!utgpu!jarvis.csri.toronto.edu!neat.ai.toronto.edu!root
From: diana@csri.toronto.edu (Diana Li)
Subject: Jan Chomicki, Thursday 22 June 1989: SYSTEMS SEMINAR
Message-ID: <8906131318.AA06480@bloor.csri.toronto.edu>
Organization: Department of Computer Science, University of Toronto
Date: Tue, 13 Jun 89 09:18:27 EDT

                            FLASH ANNOUNCEMENT
         (SF = Sandford Fleming Building, 10 King's College Road)

       -------------------------------------------------------------

                              SYSTEMS SEMINAR
               SF 4103, at 11:00 a.m., Thursday 22 June 1989

                               Jan Chomicki
                          University of Maryland

      "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.

(_T_h_i_s _n_o_t_i_c_e _s_u_p_e_r_s_e_d_e_s _a_n _e_a_r_l_i_e_r _a_n_n_o_u_n_c_e_m_e_n_t _i_n _w_h_i_c_h _t_h_e _d_a_t_e _w_a_s
_w_r_o_n_g_l_y _t_y_p_e_d _a_s _F_r_i_d_a_y _2 _J_u_n_e.)