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(rdfs_entailment, 33 [ 34 ]). 35:- use_module(rdfql(rdfql_runtime)). % runtime tests 36:- use_module(library(nb_set)). 37:- use_module(library('semweb/rdf_db'), 38 [ rdf_current_predicate/1, 39 rdf_global_id/2, 40 rdf_reachable/3, 41 rdf_has/3, 42 rdf_has/4, 43 rdf_subject/1, 44 rdf_equal/2, 45 (rdf_meta)/1, 46 op(_,_,_) 47 ]). 48:- use_module(library('semweb/rdfs'), 49 [ rdfs_subclass_of/2, 50 rdfs_subproperty_of/2 51 ]).

RDFS entailment

The function of an entailment module is to provide an implementation of rdf/3 that extends basic triple-lookup using the entailment rules of the semantic web sub language of RDF.

This entailment module does RDFS entailment.

To be done: - Check the completeness */

64:- rdf_meta 65 rdf(o,o,o), 66 individual_of(r,r). 67 68:- public 69 rdf/3, 70 rdf/4. 71 72rdf(literal(L), _, _) :- % should move to compiler 73 nonvar(L), !, fail. 74rdf(_, literal(L), _) :- % idem 75 nonvar(L), !, fail. 76rdf(S, P, O) :- 77 var(P), !, 78 ( rdf_db:rdf(S,P,O) 79 ; rdf(P, rdf:type, rdf:'Property'), 80 rdf(S, P, O), 81 \+ rdf_db:rdf(S,P,O) 82 ). 83rdf(S, P, C) :- 84 rdf_reachable(rdf:type, rdfs:subPropertyOf, P), !, 85 individual_of(S, C). 86rdf(S, P, O) :- % transitive predicates 87 rdf_reachable(rdfs:subClassOf, rdfs:subPropertyOf, P), !, 88 ( (nonvar(S) ; nonvar(O)) 89 -> rdfs_subclass_of(S, O) % generate from given start 90 ; individual_of(S, rdfs:'Class'), % generated unbounded (slow!) 91 rdfs_subclass_of(S, O) 92 ). 93rdf(S, rdfs:subPropertyOf, O) :- !, 94 ( nonvar(S) 95 -> individual_of(S, rdf:'Property'), 96 rdfs_subproperty_of(S, O) 97 ; nonvar(O) 98 -> individual_of(O, rdf:'Property'), 99 rdfs_subproperty_of(S, O) 100 ; individual_of(S, rdf:'Property'), 101 rdfs_subproperty_of(S, O) 102 ). 103rdf(S, serql:directSubClassOf, O) :- !, 104 rdf_has(S, rdfs:subClassOf, O). 105rdf(S, serql:directType, O) :- !, 106 rdf_has(S, rdf:type, O). 107rdf(S, serql:directSubPropertyOf, O) :- !, 108 rdf_has(S, rdfs:subPropertyOf, O). 109rdf(S, P, O) :- 110 rdf_has(S, P, O).

125individual_of(Resource, Class) :- 126 nonvar(Resource), !, 127 ( Resource = literal(_) 128 -> rdfs_subclass_of(Class, rdfs:'Literal') 129 ; rdfs_has_type(Resource, MyClass), 130 rdfs_subclass_of(MyClass, Class) 131 ; rdf_equal(Class, rdfs:'Resource') 132 ). 133individual_of(Resource, Class) :- 134 nonvar(Class), !, 135 ( rdf_equal(Class, rdfs:'Resource') 136 -> rdf_subject(Resource) 137 ; rdfs_subclass_of(SubClass, Class), 138 rdfs_has_type(Resource, SubClass) 139 ). 140individual_of(Resource, Class) :- 141 rdf_subject(Resource), 142 individual_of(Resource, Class).

151rdfs_has_type(Resource, Class) :- 152 empty_nb_set(Set), 153 ( atom(Resource) 154 -> ( rdf_has(Resource, rdf:type, Class) 155 ; rdf_db:rdf(Resource, P, _), 156 rdf_has(P, rdfs:domain, Class) 157 ; rdf_db:rdf(_, P, Resource), 158 rdf_has(P, rdfs:range, Class) 159 ; rdf_db:rdf(Resource, rdfs:subPropertyOf, _), 160 rdf_equal(Class, rdf:'Property') 161 ; rdf_db:rdf(_, rdfs:subPropertyOf, Resource), 162 rdf_equal(Class, rdf:'Property') 163 ; ( rdf_db:rdf(_,Resource,_) 164 -> rdf_equal(Class, rdf:'Property'), 165 \+ rdf_has(Resource, rdf:type, Class) 166 ) 167 ), 168 add_nb_set(Class, Set, New), 169 New == true 170 ; atom(Class) 171 -> ( rdf_has(Resource, rdf:type, Class) 172 ; rdf_has(P, rdfs:domain, Class), 173 rdf_has(Resource, P, _) 174 ; rdf_has(P, rdfs:range, Class), 175 rdf_has(_, P, Resource) 176 ; ( rdf_reachable(Class, rdfs:subClassOf, rdf:'Property') 177 -> rdf_current_predicate(Resource), 178 ( rdf(_,Resource,_) 179 -> \+ rdf_has(Resource, rdf:type, Class) 180 ) 181 ) 182 ), 183 add_nb_set(Resource, Set, New), 184 New == true 185 ; throw(error(instantiation_error, _)) 186 ). 187 188 189 /******************************* 190 * REGISTER * 191 *******************************/ 192 193:- multifile 194 cliopatria:entailment/2. 195 196cliopatria:entailment(rdfs, rdfs_entailment)