Semantic Knowledge Engineering (SKE) is an open initiative for authoritative semantic modeling, implementation projection, persistent publication, and executable knowledge in which semantics remain explicit through execution.
SKE is an initiative and governance/architecture repository. It is not an ontology and does not mint an ske: vocabulary merely to describe itself.
SKE is easiest to understand as one connected path through several deliberately separate repositories:
Authoritative semantic source / meaning
↓ represented and governed as
Semantic Model
↓ optionally projected into
Implementation Projection
↓ operationalized while preserving semantic lineage
Executable Semantic Knowledge Architecture
↓ tested against concrete evidence
Reference domains + executable evidence
The repositories keep different ownership boundaries even when they participate in the same path:
- Start with SKE for the initiative architecture, shared principles, repository map, and current sequencing.
- Read SMO for the deliberately small reusable distinction between an authoritative
SemanticModeland a non-authoritativeImplementationProjection. - Read ESKA for the execution architecture under the principle that semantics must remain explicit through execution.
- Use Pizza Ontology as the concrete preservation/reference and executable proving ground, then Semantic Modeling Pizza for the SMO-oriented reference path.
- Use Semantic Modeling Wine/Food as independent cross-domain evidence that tests which patterns actually generalize and which should remain local.
Useful shortcuts:
- Ontology / Semantic Web / knowledge-graph practitioners: Pizza Ontology → SMO → Semantic Modeling Pizza → Wine/Food.
- Solution / enterprise / knowledge architects: SKE principles → SMO → ESKA → reference evidence.
- AI / agent architecture practitioners: ESKA → Pizza executable evidence → SKE semantic-ownership and provenance boundaries.
- Developers seeking a reproducible path: Pizza Ontology and ESKA provide the densest executable examples and verification contracts.
The common rule is that a repository may consume, project, operationalize, or test semantics without silently becoming their authority.
For a cross-cutting orientation across standards, tooling, SKE concepts, related work and evidence, see the SKE concept and responsibility map. For source-grounded comparisons with independently developed approaches, see the SKE related-work index.
SKE owns cross-repository material that is useful precisely because it spans more than one participating repository:
- initiative-level architecture and ecosystem relationships;
- evidence-backed shared principles;
- shared engineering, documentation, and publication conventions;
- cross-repository decisions when a decision genuinely spans repository boundaries;
- dependency and adoption sequencing.
SKE does not become authoritative for semantic concepts owned by participating repositories. Repository-local rules may specialize or override shared conventions when the local reason is explicit.
| Repository | Category | Role | Semantic ownership |
|---|---|---|---|
| Semantic Knowledge Engineering | Initiative / governance | Initiative architecture, governance, shared conventions, roadmap and ecosystem map | No initiative vocabulary by default |
| Semantic Modeling Ontology | Semantic foundations | Small reusable semantic-modeling vocabulary | SemanticModel, ImplementationProjection |
| Executable Semantic Knowledge Architecture | Execution architecture | Architecture for semantic continuity through execution, result, verification, service, agent and deployment concerns | ESKA execution architecture |
| Pizza Ontology | Reference / preservation project | Preservation/reference project and proving ground for the historical Pizza ontology and repository-authored evidence | Pizza domain semantics remain source-owned; repository owns preservation/reference evidence |
| Semantic Modeling Pizza | Semantic modeling reference example | SMO-oriented reference example using Pizza without taking ownership of the Pizza ontology | Example-local modeling and projection evidence only |
| Semantic Modeling Wine/Food | Semantic modeling reference example | Cross-domain SMO-oriented Wine/Food reference example built from historical W3C teaching-domain semantics | Example-local modeling evidence only; original Wine/Food authority remains external |
| GerhardBalz/w3id.org | Supporting publication infrastructure | Working fork used to prepare persistent identifier redirect changes for upstream perma-id/w3id.org |
None; infrastructure only |
The repositories are related but independently governed. Shared conventions are adopted by participating repositories; they are not silently imposed by SKE.
The detailed repository responsibilities, lifecycle state and local backlog anchors are maintained in architecture/repository-map.md.
pizza-ontology and semantic-modeling-pizza deliberately serve different purposes:
- Pizza Ontology preserves, references and tests the historical Pizza ontology and its repository-authored evidence without rewriting historical identity or claiming authority over upstream namespaces.
- Semantic Modeling Pizza is an SKE reference example for applying SMO-oriented modeling distinctions such as semantic model, implementation projection, runtime data, validation/inference evidence and agent contract.
Reusable findings should flow upward to SKE or SMO through explicit review rather than by silently generalizing example-specific choices.
The first SKE baseline contains only material already supported by implemented cross-repository evidence:
- Semantics must remain explicit through execution
- Semantic identity is independent of publication backend
- Publication lifecycle
- Semantic Markdown
- Repository licensing and third-party rights
SKE records decisions here only when the evidence and consequences genuinely span participating repositories. Semantic ownership remains with the owning repositories.
- SMO–ESKA–Pizza alignment recommendation — reviewed cross-repository alignment decision implemented in downstream repositories; the governed SMO and ESKA publication steps described by that cycle are complete.
The active public initiative sequence is maintained in roadmap/current-sequence.md. The durable public handover checkpoint is SKE #32.
Repository-local work remains authoritative in the relevant repository backlog; SKE links and sequences that work rather than duplicating it.
The public initiative/reference baseline spans SKE, SMO, ESKA, Pizza Ontology, Semantic Modeling Pizza, and Semantic Modeling Wine/Food.
The initiative-level semantic-continuity work is complete: SKE #39 was implemented through SKE PR #40 and reconciled downstream through ESKA PR #95.
Recent cross-cutting publication work is also complete: the concept/responsibility map was published through SKE PR #41, and reviewed related-work notes for AI Unified Process / Spec-Driven Development and Knowledge Spine were published through SKE PRs #42 and #43.
The only active public P1 gate is:
- Pizza #72 — external stewardship/provenance gate before any preservation/reference W3ID submission.
Pizza #4 remains parked until a concrete semantic-modernization requirement exists. SMO, ESKA, Semantic Modeling Pizza, and Semantic Modeling Wine/Food currently have no open repository-local issues.
Original SKE-authored material is licensed under the MIT License (SPDX-License-Identifier: MIT).
Externally authored standards, ontologies, datasets, benchmark material, papers, repositories, quotations, and other referenced evidence remain governed by their respective rights holders and terms. See NOTICE.md for the repository boundary.