Aevum Ontology Specification v3.4

1. Introduction

The Aevum Ontology defines the structural semantics of knowledge entities within the Aevum Encyclopedia platform. It provides a unified framework for representing concepts, events, persons, artifacts, and their relationships with machine-readable precision and human-readable clarity.

1.1 Scope

This specification covers:

• Core entity types and hierarchical classification.
• Property definitions with cardinality and range constraints.
• Temporal validity modeling via ISO 8601 intervals.
• Source attribution and provenance tracking.
• Multi-lingual label handling.
• JSON-LD and SPARQL interface mappings.

1.2 Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119.

2. Core Classes

The ontology defines a hierarchy rooted in Aevum:Thing. The following table summarizes the primary classes:

3. Properties

Properties define the attributes and relationships of entities. The following table lists global properties applicable across multiple classes.

4. Relations

Relations define typed edges between entities. Unlike generic properties, relations carry semantic weight in the knowledge graph traversal.

5. Temporal Semantics

Version 3.4 introduces strict temporal validity modeling. Every entity may exist over a defined time interval. Queries MUST respect temporal context when retrieving data.

# Temporal Validity Example
ae:phys:quantum_entanglement a Aevum:Concept ;
    ae:label "Quantum Entanglement"@en ;
    ae:validFrom "1935-01-01T00:00:00Z"^^xsd:dateTime ;
    ae:validUntil "9999-12-31T23:59:59Z"^^xsd:dateTime .

# Historical Event with Bounded Interval
ae:hist:renaissance_florence a Aevum:Event ;
    ae:label "Florentine Renaissance"@en ;
    ae:validFrom "1300-01-01T00:00:00Z"^^xsd:dateTime ;
    ae:validUntil "1600-12-31T23:59:59Z"^^xsd:dateTime .

6. JSON-LD Mapping

The following example demonstrates the JSON-LD representation of a Aevum:Concept entity conforming to specification v3.4.

{
  "@context": "https://schema.aevum.enc/v3.4/context.jsonld",
  "@type": "Aevum:Concept",
  "ae:id": "ae:bio:photosynthesis",
  "ae:label": [
    {
      "@value": "Photosynthesis",
      "@language": "en"
    },
    {
      "@value": "Fotosíntesis",
      "@language": "es"
    }
  ],
  "ae:definition": "The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.",
  "ae:category": [
    "ae:cat:biology",
    "ae:cat:chemistry"
  ],
  "ae:validFrom": "0001-01-01T00:00:00Z",
  "ae:source": [
    {
      "@id": "ae:src:campbell_biology_12th"
    },
    {
      "@id": "ae:src:ncbi_pmid_12345678"
    }
  ],
  "ae:modifiedAt": "2025-01-14T09:23:11Z"
}

7. Validation Rules

Entities submitted to the Aevum knowledge graph MUST pass the following validation checks:

1. Unique ID: The ae:id MUST be globally unique within the namespace.
2. Label Presence: At least one ae:label MUST be provided in the English language.
3. Source Attribution: All entities of type Aevum:Concept and Aevum:Event MUST have at least one ae:source link.
4. Temporal Integrity: ae:validFrom < ae:validUntil.
5. Relation Consistency: Transitive relations (e.g., ae:subclassOf) MUST NOT contain cycles.

# Detect entities missing required sources
SELECT ?entity ?label
WHERE {
  ?entity a Aevum:Concept .
  ?entity ae:label ?label .
  FILTER (NOT EXISTS { ?entity ae:source ?src })
}

8. Changelog (v3.4)