haskell@gentoo.org
Gentoo Haskell
Haskellers are usually familiar with monoids and semigroups. A monoid has an appending operation `<>` (or `mappend`),
and an identity element, `mempty`. A semigroup has an appending `<>` operation, but does not require a `mempty` element.
A Semiring has two appending operations, `plus` and `times`, and two respective identity elements, `zero` and `one`.
More formally, a Semiring R is a set equipped with two binary relations `+` and `*`, such that:
(R,+) is a commutative monoid with identity element 0,
(R,*) is a monoid with identity element 1,
(*) left and right distributes over addition, and
multiplication by '0' annihilates R.