peano-axioms is a crate for type-level arithmetic based on an extension of the Peano axioms.
use peano_axioms::{One, Two, Three, Six, Product};
assert_eq!(Product::<Two, Three>::VALUE, Six::VALUE);
assert_eq!(Difference::<Three, Two>::VALUE, One::VALUE);
// Fails to compile
// assert_eq!(Difference::<Two, Three>::VALUE, One::VALUE);