Defining Reasoning Rules

This page demonstrates how to define class hierarchies and OWL properties that enable automatic inference in Fluree.

Class Hierarchies with rdfs:subClassOf

The taxonomic hierarchy is built using rdfs:subClassOf:

{
  "@context": {
    "rdfs": "http://www.w3.org/2000/01/rdf-schema#",
    "bio": "https://biology-example.com/ns/"
  },
  "insert": [
    {
      "id": "bio:classes/Animal",
      "type": "rdfs:Class",
      "rdfs:label": "Animal"
    },
    {
      "id": "bio:classes/Mammal",
      "type": "rdfs:Class",
      "rdfs:label": "Mammal",
      "rdfs:subClassOf": { "id": "bio:classes/Animal" }
    },
    {
      "id": "bio:classes/Carnivore",
      "type": "rdfs:Class",
      "rdfs:label": "Carnivore",
      "rdfs:subClassOf": { "id": "bio:classes/Mammal" }
    },
    {
      "id": "bio:classes/Feline",
      "type": "rdfs:Class",
      "rdfs:label": "Feline",
      "rdfs:subClassOf": { "id": "bio:classes/Carnivore" }
    }
  ]
}

This creates the chain: Feline → Carnivore → Mammal → Animal

Adding an Organism

When you add a Tiger typed as Feline:

{
  "@context": {
    "schema": "http://schema.org/",
    "bio": "https://biology-example.com/ns/"
  },
  "insert": {
    "id": "bio:organisms/tiger",
    "type": ["bio:Organism", "bio:classes/Feline"],
    "schema:name": "Tiger",
    "bio:scientificName": "Panthera tigris"
  }
}

With reasoning enabled, the Tiger is automatically inferred to be:

A Feline (asserted)
A Carnivore (inferred)
A Mammal (inferred)
An Animal (inferred)

Inverse Properties

Define two properties as inverses of each other:

{
  "@context": {
    "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
    "owl": "http://www.w3.org/2002/07/owl#",
    "bio": "https://biology-example.com/ns/"
  },
  "insert": [
    {
      "id": "bio:properties/eats",
      "type": ["rdf:Property", "owl:ObjectProperty"],
      "rdfs:label": "eats",
      "rdfs:comment": "Predator eats prey"
    },
    {
      "id": "bio:properties/eatenBy",
      "type": ["rdf:Property", "owl:ObjectProperty"],
      "rdfs:label": "eaten by",
      "owl:inverseOf": { "id": "bio:properties/eats" }
    }
  ]
}

Now when you assert a predator-prey relationship:

{
  "insert": {
    "id": "bio:organisms/lion",
    "bio:properties/eats": { "id": "bio:organisms/deer" }
  }
}

The inverse is automatically inferred:

bio:organisms/deer bio:properties/eatenBy bio:organisms/lion

Symmetric Properties

For bidirectional relationships, use owl:SymmetricProperty:

{
  "@context": {
    "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
    "owl": "http://www.w3.org/2002/07/owl#",
    "bio": "https://biology-example.com/ns/"
  },
  "insert": {
    "id": "bio:properties/relatedTo",
    "type": ["rdf:Property", "owl:ObjectProperty", "owl:SymmetricProperty"],
    "rdfs:label": "related to",
    "rdfs:comment": "Symmetric biological relationship"
  }
}

Assert one direction:

{
  "insert": {
    "id": "bio:organisms/lion",
    "bio:properties/relatedTo": { "id": "bio:organisms/tiger" }
  }
}

The reverse is automatically inferred:

bio:organisms/tiger bio:properties/relatedTo bio:organisms/lion

Transitive Properties

For chains of relationships, use owl:TransitiveProperty:

{
  "insert": {
    "id": "bio:properties/ancestorOf",
    "type": ["rdf:Property", "owl:ObjectProperty", "owl:TransitiveProperty"],
    "rdfs:label": "ancestor of"
  }
}

If you assert:

A ancestorOf B
B ancestorOf C

Then A ancestorOf C is automatically inferred.

Custom Rules

For more complex inference, Fluree supports custom rules:

{
  "@context": {
    "f": "https://ns.flur.ee/ledger#",
    "bio": "https://biology-example.com/ns/"
  },
  "@id": "bio:rules/endangered-in-habitat",
  "f:rule": {
    "@type": "@json",
    "@value": {
      "@context": { "bio": "https://biology-example.com/ns/" },
      "where": [
        { "@id": "?organism", "bio:habitat": "?habitat" },
        { "@id": "?organism", "bio:conservationStatus": "Endangered" }
      ],
      "insert": { "@id": "?habitat", "bio:hasEndangeredSpecies": { "@id": "?organism" } }
    }
  }
}

This rule infers that a habitat has endangered species when any organism in that habitat has "Endangered" conservation status.

Enabling Reasoning

Reasoning can be enabled at query time:

{
  "select": { "?organism": ["*"] },
  "where": { "@id": "?organism", "@type": "bio:classes/Mammal" },
  "opts": {
    "reasoner": "owl2rl"
  }
}

Or configured at the ledger level for automatic reasoning on all queries.

Summary

Technique	Use Case
`rdfs:subClassOf`	Class hierarchies (is-a relationships)
`owl:inverseOf`	Bidirectional properties (eats ↔ eatenBy)
`owl:SymmetricProperty`	Same property both directions
`owl:TransitiveProperty`	Chained relationships (A→B→C implies A→C)
Custom rules (`f:rule`)	Complex custom inference

Next, learn how to query inferred data alongside asserted facts.

Class Hierarchies with rdfs:subClassOf​

Adding an Organism​

Inverse Properties​

Symmetric Properties​

Transitive Properties​

Custom Rules​

Enabling Reasoning​

Summary​