1/* Part of ClioPatria SeRQL and SPARQL server 2 3 Author: Jan Wielemaker 4 E-mail: J.Wielemaker@cs.vu.nl 5 WWW: http://www.swi-prolog.org 6 Copyright (C): 2004-2010, University of Amsterdam, 7 VU University Amsterdam 8 9 This program is free software; you can redistribute it and/or 10 modify it under the terms of the GNU General Public License 11 as published by the Free Software Foundation; either version 2 12 of the License, or (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public 20 License along with this library; if not, write to the Free Software 21 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 22 23 As a special exception, if you link this library with other files, 24 compiled with a Free Software compiler, to produce an executable, this 25 library does not by itself cause the resulting executable to be covered 26 by the GNU General Public License. This exception does not however 27 invalidate any other reasons why the executable file might be covered by 28 the GNU General Public License. 29*/ 30 31 32:- module(rdfslite_entailment, 33 [ 34 ]). 35:- use_module(rdfql(rdfql_runtime)). % runtime tests 36:- use_module(library('semweb/rdf_db'), 37 [ rdf_global_id/2, 38 rdf_reachable/3, 39 rdf_has/3, 40 rdf_has/4, 41 rdf_subject/1, 42 rdf_equal/2, 43 (rdf_meta)/1, 44 op(_,_,_) 45 ]). 46:- use_module(library('semweb/rdfs'), 47 [ rdfs_subclass_of/2, 48 rdfs_subproperty_of/2, 49 rdfs_individual_of/2 50 ]). 51 52/** <module> RDFS-Lite entailment 53 54The function of an entailment module is to provide an implementation of 55rdf/3 that extends basic triple-lookup using the entailment rules of the 56semantic web sub language of RDF. 57 58This entailment module does the part of RDFS that can be implemented 59efficiently using backward chaining. Notably it does *not* do 60type-reasoning on the basis of domains/ranges of properties. It does: 61 62 * Use the property hierarchy 63 * Define the serql special relations 64 * Handle rdfs:subClassOf as transitive 65 * Handle rdfs:subPropertyOf as transitive 66 * Handle rdf:type using subProperties and rdfs:subClassOf 67*/ 68 69:- rdf_meta 70 rdf(o,o,o). 71 72:- public 73 rdf/3, 74 rdf/4. 75 76rdf(S, P, O) :- 77 var(P), !, 78 rdf_db:rdf(S,P,O). 79rdf(S, serql:directSubClassOf, O) :- !, 80 rdf_has(S, rdfs:subClassOf, O). 81rdf(S, serql:directType, O) :- !, 82 rdf_has(S, rdf:type, O). 83rdf(S, serql:directSubPropertyOf, O) :- !, 84 rdf_has(S, rdfs:subPropertyOf, O). 85rdf(S, rdfs:subClassOf, O) :- ( atom(S) ; atom(O) ), !, 86 rdf_reachable(S, rdfs:subClassOf, O). 87rdf(S, rdfs:subClassOf, O) :- !, 88 rdf_has(S, rdfs:subClassOf, Direct), 89 rdf_reachable(Direct, rdfs:subClassOf, O). 90rdf(S, rdfs:subPropertyOf, O) :- !, 91 rdf_reachable(S, rdfs:subPropertyOf, O). 92rdf(S, rdf:type, O) :- !, 93 ( var(S), var(O) 94 -> rdf_subject(S) 95 ; true 96 ), 97 rdfs_individual_of(S, O). 98rdf(S, P, O) :- 99 rdf_has(S, P, O). 100 101%! rdf(?S, ?P, ?O, ?G) 102 103rdf(S, P, O, G) :- 104 var(P), 105 !, 106 rdf_db:rdf(S, P, O, G). 107rdf(S, P, O, G) :- 108 rdf_has(S, P, O, RP), 109 rdf_db:rdf(S, RP, O, G). 110 111 /******************************* 112 * REGISTER * 113 *******************************/ 114 115:- multifile 116 cliopatria:entailment/2. 117 118cliopatriaentailment(rdfslite, rdfslite_entailment)