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Package RDFClosure :: Module OWLRL :: Class OWLRL_Semantics
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Class OWLRL_Semantics

source code

Closure.Core --+
               |
              OWLRL_Semantics
Known Subclasses:

OWL 2 RL Semantics class, ie, implementation of the OWL 2 RL closure graph.

Note that the module does not implement the so called Datatype entailment rules, simply because the underlying RDFLib does not implement the datatypes (ie, RDFLib will not make the literal "1.00" and "1.00000" identical, although even with all the ambiguities on datatypes, this should be made equal...). Also, the so-called extensional entailment rules (Section 7.3.1 in the RDF Semantics document) have not been implemented either.

The comments and references to the various rule follow the names as used in the OWL 2 RL document.

Instance Methods [hide private]
 
__init__(self, graph, axioms, daxioms, rdfs=None) source code
 
_list(self, l)
Shorthand to get a list of values (ie, from an rdf:List structure) starting at a head		 source code
 
_get_resource_or_literal(self, node) source code
 
post_process(self)
Remove triples with bnode predicates.		 source code
 
add_axioms(self)
Add axioms		 source code
 
add_d_axioms(self)
Add the datatype axioms		 source code
 
restriction_typing_check(self, v, t)
Helping method to check whether a type statement is in line with a possible restriction.		 source code
 
_one_time_rules_datatypes(self)
Some of the rules in the rule set are axiomatic in nature, meaning that they really have to be added only once, there is no reason to add these in a cycle.		 source code
 
_one_time_rules_misc(self)
Rules executed: cls-thing, cls-nothing, prp-ap.		 source code
 
one_time_rules(self)
Some of the rules in the rule set are axiomatic in nature, meaning that they really have to be added only once, there is no reason to add these in a cycle.		 source code
 
rules(self, t, cycle_num)
Go through the various rule groups, as defined in the OWL-RL profile text and implemented via local methods.		 source code
 
_property_chain(self, p, x)
Implementation of the property chain axiom, invoked from inside the property axiom handler.		 source code
 
_equality(self, triple, cycle_num)
Table 4: Semantics of equality.		 source code
 
_properties(self, triple, cycle_num)
Table 5: The Semantics of Axioms about Properties.		 source code
 
_classes(self, triple, cycle_num)
Table 6: The Semantics of Classes.		 source code
 
_class_axioms(self, triple, cycle_num)
Table 7: Class Axioms.		 source code
 
_schema_vocabulary(self, triple, cycle_num)
Table 9: The Semantics of Schema Vocabulary.		 source code

Inherited from Closure.Core: add_error, closure, empty_stored_triples, flush_stored_triples, get_literal_value, pre_process, store_triple

Instance Variables [hide private]

Inherited from Closure.Core: IMaxNum, added_triples, axioms, daxioms, error_messages, graph, literal_proxies, rdfs

Method Details [hide private]

__init__(self, graph, axioms, daxioms, rdfs=None)
(Constructor)

source code 
Parameters:
  • graph (rdflib.Graph) - the RDF graph to be extended
  • axioms (bool) - whether (non-datatype) axiomatic triples should be added or not
  • daxioms (bool) - whether datatype axiomatic triples should be added or not
  • rdfs (boolean) - whether RDFS inference is also done (used in subclassed only)
Overrides: Closure.Core.__init__

_list(self, l)

source code 

Shorthand to get a list of values (ie, from an rdf:List structure) starting at a head

Parameters:
  • l - RDFLib resource, should be the head of an rdf:List
Returns:
array of resources

post_process(self)

source code 

Remove triples with bnode predicates. The Bnodes in the graph are collected in the first cycle run.

Overrides: Closure.Core.post_process

add_axioms(self)

source code 

Add axioms

Overrides: Closure.Core.add_axioms

add_d_axioms(self)

source code 

Add the datatype axioms

Overrides: Closure.Core.add_d_axioms

restriction_typing_check(self, v, t)

source code 

Helping method to check whether a type statement is in line with a possible restriction. This method is invoked by rule "cls-avf" before setting a type on an allValuesFrom restriction.

The method is a placeholder at this level. It is typically implemented by subclasses for extra checks, eg, for datatype facet checks.

Parameters:
  • v - the resource that is to be 'typed'
  • t - the targeted type (ie, Class)
Returns:
boolean

_one_time_rules_datatypes(self)

source code 

Some of the rules in the rule set are axiomatic in nature, meaning that they really have to be added only once, there is no reason to add these in a cycle. These are performed by this method that is invoked only once at the beginning of the process.

These are: cls-thing, cls-nothing1, prp-ap, dt-types1, dt-types2, dt-eq, dt-diff.

Note, however, that the dt-* are executed only partially, limited by the possibilities offered by RDFLib. These may not cover all the edge cases of OWL RL. Especially, dt-not-type has not (yet?) been implemented (I wonder whether RDFLib should not raise exception for those anyway...

one_time_rules(self)

source code 

Some of the rules in the rule set are axiomatic in nature, meaning that they really have to be added only once, there is no reason to add these in a cycle. These are performed by this method that is invoked only once at the beginning of the process.

These are: cls-thing, cls-nothing1, prp-ap, dt-types1, dt-types2, dt-eq, dt-diff.

Overrides: Closure.Core.one_time_rules

rules(self, t, cycle_num)

source code 

Go through the various rule groups, as defined in the OWL-RL profile text and implemented via local methods. (The calling cycle takes every tuple in the graph.)

Parameters:
  • t - a triple (in the form of a tuple)
  • cycle_num - which cycle are we in, starting with 1. This value is forwarded to all local rules; it is also used locally to collect the bnodes in the graph.
Overrides: Closure.Core.rules

_property_chain(self, p, x)

source code 

Implementation of the property chain axiom, invoked from inside the property axiom handler. This is the implementation of rule prp-spo2, taken aside for an easier readability of the code.

_equality(self, triple, cycle_num)

source code 

Table 4: Semantics of equality. Essentially, the eq-* rules.

Parameters:
  • triple - triple to work on
  • cycle_num - which cycle are we in, starting with 1. Can be used for some optimization.

_properties(self, triple, cycle_num)

source code 

Table 5: The Semantics of Axioms about Properties. Essentially, the prp-* rules.

Parameters:
  • triple - triple to work on
  • cycle_num - which cycle are we in, starting with 1. Can be used for some optimization.

_classes(self, triple, cycle_num)

source code 

Table 6: The Semantics of Classes. Essentially, the cls-* rules

Parameters:
  • triple - triple to work on
  • cycle_num - which cycle are we in, starting with 1. Can be used for some optimization.

_class_axioms(self, triple, cycle_num)

source code 

Table 7: Class Axioms. Essentially, the cax-* rules.

Parameters:
  • triple - triple to work on
  • cycle_num - which cycle are we in, starting with 1. Can be used for some optimization.

_schema_vocabulary(self, triple, cycle_num)

source code 

Table 9: The Semantics of Schema Vocabulary. Essentially, the scm-* rules

Parameters:
  • triple - triple to work on
  • cycle_num - which cycle are we in, starting with 1. Can be used for some optimization.

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