Removal of errant concept owl:ontologyIRI

[ajnelson-nist]

Background

Issue 488 noted that a non-existent OWL concept was introduced. This came in during implementation of the UCO shapes-based OWL review mechanism of Issue 437.

This Issue is a bug fix, in terms of semantic impact to UCO. There is no negative semantic impact, and an error found when using UCO's OWL shapes to review any non-UCO ontology using owl:versionIRI is fixed. However, it is being posted for discussion and a fast-track vote due to a non-trivial revision to the tests around owl:imports and owl:incompatibleWith.

This Issue also happens to be a discussion starter for how to handle deprecating concept IRIs, as some of the shapes defined to review owl:ontologyIRI are now moot.

Requirements

Requirement 1

All IRI-structured references to owl:ontologyIRI need to be stricken from UCO and its tests.

Requirement 2

Concepts that are reduced to "Stub" concepts, not intended for users to encounter or use, must remain in UCO until at least the next major version.

Aside: An expected discussion point - should deprecated concept IRIs always be removed in the next major version, or the following major version? I.e. 2.0.0 or 3.0.0 here? Or, should they be retained forever?

Risk / Benefit analysis

Benefits

• Fixes a bug based on an errant concept.
• Removes errant complaints against all other ontologies using owl:versionIRI.

Risks

• Tests exercising the non-concept owl:ontologyIRI require significant revision to meet the same objectives indicated from the OWL specifications.

Competencies demonstrated

Competency 1

owl:imports can import ontologies either by their ontology IRI, or their owl:versionIRI value. Similarly, owl:incompatibleWith can designate incompatibilities by ontology IRI or owl:versionIRI value. Incompatibility warnings should be raised whenever an owl:Ontology is recognized either by a node's rdf:type designation or being the subject of a owl:versionIRI triple, where the object of that triple is a noted incompatibility anywhere in the graph.

Competency Question 1.1

What owl:imports incompatibity patterns are tested now?

Result 1.1

See this figure (probably best-viewed downloaded and un-zoomed), an illustration of owl_incompatibleWith_shape_PASS.ttl in the linked Pull Request:

Roughly each graph, except for two of them, introduces a test complication over the just-prior graph when viewing from left to right. Colors indicate: red for incompatibility designations, and gray for version-related concepts.

Examples 1 and 6 are expected to not trigger any import-incompatibility warnings. Each other graph in that illustration is expected to trigger a warning. These expectations are encoded in a unit test under tests/shapes/examples_uco_owl/.

The figure was generated by import_closure.py, provided in the CASE-Examples-QC repository.

Solution suggestion

• Strike all references to owl:ontologyIRI from uco-owl shapes.
• Strike all references to owl:ontologyIRI from each UCO ontology file.
• For any shapes rendered wholly moot by removal of owl:ontologyIRI, retain their IRIs, but:
  • Reduce their type to sh:Shape (instead of sh:NodeShape or sh:PropertyShape);
  • Comment they are deprecated;
  • Comment they will be removed in UCO 2.0.0. (Or, if the OC prefers, UCO 3.0.0.)
• Re-construct OWL incompatibleWith test cases using a more methodical pattern, spelling nodes by grouping. (This is what's illustrated under competency question result 1.1.)
• Make other revisions to uco-owl unit tests necessary to accommodate the ontology IRI being what owl:ontologyIRI errantly tried to represent.

Coordination

• Tracking in Jira ticket OC-275
• Administrative review completed, proposal announced to Ontology Committees (OCs) on 2022-10-26
• Solution announced to OCs on 2022-10-26
• Decision recorded on whether concept IRIs should be deleted in some next major version
• Solutions Approval to be discussed in OC meeting, 2022-11-17
• Solutions Approval vote occurred, passing, on 2022-11-17
• Solutions development phase completed.
• UCO implementation merged into develop
• CASE implementation merged into develop
• Milestone linked
• Documentation logged in pending UCO release page
• Documentation logged in pending CASE release page

[ajnelson-nist]

For THIS proposal, we will erase the IRIs for the ontology IRI tests.

[ajnelson-nist]

During this morning's meeting, the rationales for deleting the deprecated IRIs in this PR were:

• These IRIs do not pertain to OWL classes. They are instead shapes scoped to tests that turned out to be impossible to satisfy while UCO is a triples-based ontology.
• The errant shapes have not been deployed to the documentation site. (Which, yes, is an issue that still has the maintainers' attention.)

With likelihood-near-0 of a UCO consumer to ever be affected by deleting these shapes, this commit deletes them rather than deprecating them.