rify

Rify is a forward chaining inference engine designed specifically for use on in-memory RDF graphs.

It accepts conjunctive rules with limited expressiveness so reasoning is bounded by O(n^k) in both memory and in computation where n is the number of nodes in the input RDF graph.

Reasoning generates a proof which can be used to quickly verify the result pragmatically.

Logical rules are defined as if-then clauses. Something like this:

```rust struct Rule { if_all: Vec<[Entity; 3]>, then: Vec<[Entity; 3]>, }

enum Entity { /// A a named variable with an unknown value. Unbound(String), /// A literal RDF node. Bound(RdfNode), }

// actual definitions of these types are templated but this is the gist ```

Use

Two functions are central to this library: prove and validate.

``rust // Example use ofprove`

use rify::{ prove, Entity::{Unbound, Bound}, Rule, RuleApplication, };

// (?a, is, awesome) ∧ (?a, score, ?s) -> (?a score, awesome) let awesomescoreaxiom = Rule::create( vec![ [Unbound("a"), Bound("is"), Bound("awesome")], // if someone is awesome [Unbound("a"), Bound("score"), Unbound("s")], // and they have some score ], vec![[Unbound("a"), Bound("score"), Bound("awesome")]], // then they must have an awesome score )?;

asserteq!( prove::<&str, &str>( &[["you", "score", "unspecified"], ["you", "is", "awesome"]], &[["you", "score", "awesome"]], &[awesomescoreaxiom] )?, &[ // (you is awesome) ∧ (you score unspecified) -> (you score awesome) RuleApplication { ruleindex: 0, instantiations: vec!["you", "unspecified"] } ] ); ```

``rust // Example use ofvalidate`

use rify::{ prove, validate, Valid, Rule, RuleApplication, };

// (?a, is, awesome) ∧ (?a, score, ?s) -> (?a score, awesome) let awesomescoreaxiom = ...;

let proof = vec![ // (you is awesome) ∧ (you score unspecified) -> (you score awesome) RuleApplication { rule_index: 0, instantiations: vec!["you", "unspecified"] } ];

let Valid { assumed, implied } = validate::<&str, &str>( &[awesomescoreaxiom], &proof, ).map_err(|e| format!("{:?}", e))?;

// Now we know that under the given rules, if all RDF triples in assumed are true, then all // RDF triples in implied are also true. ```

recipies

In addition to normal cargo commands like cargo test and cargo check the ./justfile defines some scripts which can be useful during develompent. For example, just js-test will test the javascript bindings to this library. See ./justfile for more.

License

This project is licensed under either of Apache License, Version 2.0 or MIT license, at your option.