NO3 - A Notation3 inference engine

NO3 is a small forward-chaining inference engine for a subset of the Notation3 language.

WARNING

This is experimental sofware.

SYNOPSIS

From the command line:

# Execute the rules in one file
node bin/no3.js data/socrates.n3

# Add a local data file (repeatable option)
node bin/no3.js --file data/socrates.ttl data/socrates.n3

# Add a remote data file (repeatable option)
node bin/no3.js --url http://localhost:8080/socrates.ttl data/socrates.n3

# Add a sparql endpoint
node bin/no3.js --sparql http://localhost:8080/sparql/dataset data/socrates.n3

From a JavaScript program:

const parse    = require("../js/parse.js");
const reasoner = require("../js/reasoner.js");

const extra_sources = [
    { type: "rdfjsSource" , value: A LOCAL PARSED RDFJS source (e.g. a N3.Store) } ,
    { type: "file" , value: "http://somewhere.org/data.ttl" } ,
    { type: "sparql" , value: "http://other.org/sparql" }
];

const parsedN3 = await parse.parseN3(n3String);
const inferred = await reasoner.think(parsedN3,extra_sources);
const str      = await parse.store2string(inferred);

Installation

Need:

• Node.js
• Typescript npm install typescript -g

Installation steps:

# Clone the repository
git clone https://github.com/phochste/NO3.git

# Install depencies
cd NO3
npm install

# Compile the typescript
tsc

# Run hello world
node bin/no3.js data/socrates.ttl

Notation3 support

All NO3 formulas need to be simple:

• No cited formulas
• No paths
• No backward-chaining <=
• No owl:sameAs symbol =
• Limited support for built-ins (at this moment NONE)

A supported formula:

{ ?X :cooks ?Y. } => { ?Y :isCookedBy ?X . } .

An unsupported formula:

{ ?X :says { ?X :cooks ?Y } } => { ?X :means { ?Y :isCookedBy ?X } } .

NO3 does support simple inferences:

Given:

:Socrates a :Man.
:Man rdfs:subClassOf :Mortal.

{
    ?A rdfs:subClassOf ?B. 
    ?S a ?A.
} => 
{
    ?S a ?B
}.

Results in:

:Socrates a :Mortal.

Formules can be given in any order:

Given:

:Hank :cooks :Soup .

{ ?X :isCookedBy ?Y . } => { ?X :isOnMenuOf ?Y . }.

{ ?X :cooks ?Y. } => { ?Y :isCookedBy ?X . } .

Results in (irrespective of order of formulas):

:Soup :isCookedBy :Hank;
    :isOnMenuOf :Hank.

Support for existential and universal quantifiers.

Given:

:Hank :plays :Guitar.
:Emily :plays :Piano.

:Guitar a :MusicInstrument .
:Piano a :MusicInstrument .

{ ?S :plays [ a :MusicInstrument ] .  } => { ?S :canJoin :MyBand. }.

Results in:

:Hank :canJoin :MyBand .
:Emily :canJoin :MyBand .

Raison d'être

NO3 was developed to have basic Notation3 support in JavaScript for environments that don't require all features of a CWM or EYE processor.

Naming

NO3 read as Notation 0.3 (because the lack of features) and interpreted as the chemical compound Nitrate (NO-3), which can be a fertilizer but also an explosive (not because it is explosive fast, ..actually it is very slow compared to EYE).

This code was written for the Mellon Project "Scholarly Communication on the decentralized web" as a proof of concept.