pub fn semiring<S: Debug + PartialEq + Clone, const N: usize>(
items: &[S; N],
f: &impl Fn(S, S) -> S,
g: &impl Fn(S, S) -> S,
zero: S,
one: S
) -> Result<(), &'static str>Expand description
Defines a semiring structure.
A semiring is a set of items along with two associative binary operations f and g,
and two identity elements zero and one.
f must be commutative and g must distribute over f.
the zero of f must also be absorbing with respect to g.