OWL2 Ontology (.owl, .owl2, .ofn, .ttl)

@modelscript/owl2 (languages/owl2) brings formal ontological engineering, Description Logic ($\mathcal{SROIQ}(\mathcal{D})$) reasoning, and SPARQL / Leapfrog Triejoin graph querying directly into the ModelScript compiler.

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Supported Extensions & Formats

Extension	Format
.owl, .owl2, .ofn	W3C OWL 2 Functional-Style Syntax (Prefix(...), Ontology(...))
.ttl	RDF Turtle / Ontological Triple Assertions

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OWL 2 DL Axiom & Class Expression Lowering

lowerCstToAxioms(tree, sourceText) (languages/owl2/src/cst-lowering.ts) lowers the linear-memory CST into an arena-backed OntologyStore supporting over 35 OWL 2 DL axiom and class expression constructs:

Category	Supported OWL 2 Functional-Style Constructs
Declarations	Declaration(Class(...)), Declaration(ObjectProperty(...)), Declaration(DataProperty(...)), Declaration(NamedIndividual(...))
Class Axioms	SubClassOf, EquivalentClasses, DisjointClasses
Boolean & Nominal Class Expressions	ObjectIntersectionOf, ObjectUnionOf, ObjectComplementOf, ObjectOneOf
Object Property Restrictions	ObjectSomeValuesFrom, ObjectAllValuesFrom, ObjectHasSelf, ObjectHasValue, ObjectMinCardinality, ObjectMaxCardinality, ObjectExactCardinality
Data Property Restrictions	DataSomeValuesFrom, DataAllValuesFrom, DataMinCardinality, DataMaxCardinality, DataExactCardinality
Property Hierarchy & Inversion	SubObjectPropertyOf, SubDataPropertyOf, InverseObjectProperties, DisjointObjectProperties
Property Domains & Ranges	ObjectPropertyDomain, ObjectPropertyRange, DataPropertyDomain, DataPropertyRange
Property Characteristics	FunctionalObjectProperty, InverseFunctionalObjectProperty, ReflexiveObjectProperty, IrreflexiveObjectProperty, SymmetricObjectProperty, AsymmetricObjectProperty, TransitiveObjectProperty, FunctionalDataProperty
ABox Individual Assertions	ClassAssertion, ObjectPropertyAssertion, DataPropertyAssertion, NegativeObjectPropertyAssertion, NegativeDataPropertyAssertion, SameIndividual, DifferentIndividuals

Prefix(:=<http://example.org/spacecraft#>)
Ontology(<http://example.org/spacecraft>
  Declaration(Class(:Thruster))
  Declaration(Class(:Actuator))
  Declaration(ObjectProperty(:mountedOn))
  Declaration(DataProperty(:nominalThrustN))
  SubClassOf(:Thruster :Actuator)
  SubClassOf(:Thruster ObjectSomeValuesFrom(:mountedOn :ReactionControlPod))
  ClassAssertion(:Thruster :RCS_Thruster_A1)
  DataPropertyAssertion(:nominalThrustN :RCS_Thruster_A1 "22.0"^^xsd:double)
)

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Description Logic Tableau Reasoner & Leapfrog Triejoin

@modelscript/owl2 includes an in-memory $\mathcal{SROIQ}(\mathcal{D})$ Tableau Reasoner (TableauReasoner in languages/owl2/src/reasoner/) and a worst-case optimal Leapfrog Triejoin engine (executeBGP in languages/owl2/src/query/leapfrog.ts):

1. Consistency & Satisfiability Checking: Detects unsatisfiable classes (DisjointClasses violations, cardinality contradictions, irreflexive/asymmetric cycles, negative property assertion conflicts) and surfaces exact source diagnostics (OWL2001–OWL2005).
2. Justification & Explanation Tracing: Computes minimal unsatisfiability justifications (explain_inference) explaining why a class or individual violates ontology axioms.
3. SPARQL & Multi-Way BGP Joins: Evaluates conjunctive Basic Graph Patterns (BGPs) in $O(\text{AGM bound})$ worst-case optimal time without materializing intermediate Cartesian products.

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Interactive 2D Ontology Diagram & Bidirectional Writeback

languages/owl2/src/diagram/ provides an interactive 2D graph visualization and editing surface for OWL 2 ontologies:

• Visual Graph Projection: Renders Class nodes, NamedIndividual instances, SubClassOf inheritance hierarchies, and ObjectPropertyDomain/ObjectPropertyRange directed edges.
• Bidirectional CST Writeback (owl2Language.writeback): Adding/deleting nodes or edges in the diagram (add_node, delete_node, add_edge, delete_edge, rename_node, update_parameter) patches the Functional-Style .owl source text directly—inserting or removing Declaration(...), SubClassOf(...), or DataPropertyAssertion(...) axioms in place.

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Dedicated owl2-mcp Server Tools

The @modelscript/owl2 MCP server (languages/owl2/src/mcp/server.ts) exposes five specialized tools to AI agents:

MCP Tool	Description
validate_system_consistency	Parses an OWL 2 Functional Syntax ontology, runs the $\mathcal{SROIQ}$ Tableau Reasoner, and returns consistency status, unsatisfiable classes, and inferred SubClassOf hierarchy
query_ontology_sparql	Executes a SPARQL SELECT WHERE query over the ontology's inferred RDF triple graph
query_ontology_bgp	Evaluates a conjunctive Basic Graph Pattern (BGP) using the worst-case optimal Leapfrog Triejoin algorithm
explain_inference	Computes formal axiomatic justifications explaining why an entailment holds or why a class is unsatisfiable
trace_fault_propagation	Traces transitive fault propagation (TransitiveObjectProperty / causal links) from a starting component individual across the system topology

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Polyglot TGG Rules

@modelscript/owl2 defines 5 bidirectional Triple Graph Grammar (TGG) rules in languages/owl2/src/language.ts:

Rule Name	Source (owl2)	Target Language	Target Construct
OWL2ClassToSysML2Part	Declaration (Class)	sysml2	PartDef
OWL2SubClassToSysML2Specialization	SubClassOf	sysml2	Specialization (:>)
OWL2ObjectPropertyToSysML2Port	Declaration (ObjectProperty)	sysml2	PortUsage
OWL2DataPropertyToSysML2Attribute	Declaration (DataProperty)	sysml2	AttributeUsage
OWL2ClassToModelicaModel	Declaration (Class)	modelica	ClassDefinition (model)

Command Line Interface (msx polyglot)

OWL2 ontologies can be queried, projected, and validated using ModelScript's polyglot digital thread commands:

# Project OWL 2 DL class hierarchies and axioms into formal SysML v2 part definitions
msx polyglot project SpacecraftOntology.ofn --target=sysml2 -o Spacecraft.sysml

# Cross-query ontology symbols and digital thread twins in the unified Salsa index
msx polyglot query Spacecraft::ReactionControlPod --domain=owl2

# Verify losslessness and critical pair confluence across OWL 2 TGG synchronization rules
msx polyglot verify --strict

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Diagnostic Rules

24 rules16 error7 warning1 info Run with msx lint

All severitieserrorwarninginfo

Code	Rule	Severity	Message
O1001	parse-error	error	Syntax error near '<snippet>'.
O1002	undeclared-prefix	error	Prefix '<prefix>:' used in abbreviated IRI '<iri>' is not declared.
O1003	duplicate-prefix	warning	Prefix '<prefix>:' is declared multiple times in the ontology header.
O1004	invalid-iri	error	Invalid or malformed IRI '<iri>'.
O1005	insufficient-arity	error	OWL 2 construct '<construct>' requires at least <minArity> arguments, but got <actualArity>.
O2001	undeclared-entity	warning	Entity '<iri>' is used as a <role> without an explicit Declaration axiom.
O2002	duplicate-declaration	warning	Duplicate Declaration(<kind>(<iri>)) in ontology.
O2003	reserved-vocabulary-declaration	error	Cannot declare or redefine built-in OWL 2 / RDF / RDFS / XSD vocabulary IRI '<iri>'.
O3001	illegal-property-punning	error	Illegal OWL 2 DL punning: '<iri>' is used as both '<kindA>' and '<kindB>' (ObjectProperty, DataProperty, and AnnotationProperty vocabularies must be disjoint).
O3002	expected-object-property	error	Expected an ObjectProperty in '<construct>', but '<iri>' is declared as a DataProperty.
O3003	expected-data-property	error	Expected a DataProperty in '<construct>', but '<iri>' is declared as an ObjectProperty.
O3004	expected-class-expression	error	Expected a Class expression in '<construct>', but '<iri>' is a Datatype.
O3005	invalid-datatype	warning	Datatype '<datatypeIri>' is not in the standard OWL 2 datatype map.
O3006	datatype-literal-mismatch	error	Lexical value '<literal>' is not a valid literal for datatype '<datatypeIri>'.
O4001	non-simple-property-restriction	error	OWL 2 DL global restriction violation: non-simple (transitive or composite) property '<propertyIri>' cannot be used in '<construct>'.
O4002	contradictory-property-characteristics	error	Object property '<propertyIri>' has contradictory characteristics '<charA>' and '<charB>'.
O4003	property-hierarchy-cycle	warning	Cycle detected in property hierarchy: '<cycle>'.
O4004	class-hierarchy-cycle	info	SubClassOf cycle detected (equivalent classes): '<cycle>'.
O4005	self-referential-axiom	warning	Redundant or contradictory self-referential axiom '<axiomType>' on '<iri>'.
O5001	functional-property-clash	error	Functional/InverseFunctional property '<propertyIri>' violation: <detail>.
O5002	negative-assertion-clash	error	Negative property assertion on '<propertyIri>' for '<subjectIri>' clashes with asserted or inferred value '<target>'.
O5003	unsatisfiable-class	error	Class '<classIri>' is unsatisfiable (equivalent to owl:Nothing): <reason>.
O5004	ontology-inconsistent	error	Ontology is logically inconsistent: <explanation>
O6001	profile-el-violation	warning	Construct '<construct>' is outside the OWL 2 EL profile.

Generated from languages/owl2/src/errors.ts. All languages →