standard-classes.md

@@ -62,6 +62,7 @@ Proposals:
 - A group-like class with `zero`, `(+)` and `negate`/`(-)`.
 - (Could be further split with a monoid sub-class.)
 - A ring-like subclass adding `(*)` and `one`/`fromInteger`, with the existing `Num` class as a further subclass.
+- (Could be further split with a semiring subclass, e.g. for [natural numbers](natural).)
 
 
 Note that the `Float` and `Double` instances will not satisfy the usual axioms for these structures.
@@ -78,7 +79,6 @@ Proposals:
 
 - Add a division ring-like superclass adding these operations to the ring-like class.
   (A division ring has the same operations as a field, but does not assume commutative multiplication, allowing structures such as quaternions.)
-- (Could be further split with a semiring subclass.)
 - Add default
 
   ```wiki