Ontoplexis

Query OWL 2 ontologies with Cypher.

Ontoplexis loads an OWL/XML document into an embedded Ladybug graph whose shape is the OWL 2 structural specification, exposes raw Cypher over it, and serializes the graph losslessly back to OWL/XML. If you can write a graph query, you can introspect, test, diff, and author ontologies — no ontologist's API, no JVM.

Scope

OWL/XML         ──(one generic walker)──▶  Ladybug graph
Ladybug graph   ──(the inverse walker)──▶  OWL/XML

Ontoplexis owns the OWL/XML-to-graph mapping, embedded graph storage, Cypher access, and OWL/XML round trips. Alongside the structural graph it maintains a derived-edge table that exposes the common binary relations (subsumption, typing, labels, …) as one-hop edges — a refreshable cache over asserted structure, not inference. It does not provide typed Python classes for OWL axioms, format conversion, reasoning, or profile checking.

Relationship to the stack

Ontoplexis is the graph core for the family:

• Ontopoiesis depends on it for operator workflows: build, lint, test, diff, impact analysis, rendering, and migrations.
• Ontophora is the independent sister library for typed OWL 2 construct records. Ontoplexis deliberately keeps its structural model in the graph rather than depending on those models.

Installation

pip install ontoplexis

Pure Python; requires Python 3.11+.

Quickstart

from pathlib import Path
from ontoplexis import Ontology

ont = Ontology.from_owlxml(Path("pizza.owx").read_text())

with ont.project() as proj:
    # Derived one-hop edges for the common relations …
    rows = proj.execute(
        "MATCH (a:N)-[:D {relation: 'subclass_of'}]->(b:N) "
        "RETURN a.iri AS sub_iri, b.iri AS super_iri"
    )
    # … and the full structural graph when you need every construct.
    axioms = proj.execute(
        "MATCH (ax:N)-[:E]->(:N {iri: 'https://example.org/pizza#Margherita'}) "
        "RETURN DISTINCT ax.kind AS kind"
    )

print(ont.to_owlxml())   # lossless round trip

Documentation

The documentation covers the quickstart, graph schema, edge roles, authoring with Cypher, document conversion, and development setup.

License

Ontoplexis is licensed under the Apache License 2.0.