[Haskell-cafe] commutative monoid?

[Henning Thielemann]

On Fri, 24 Jun 2011, Evan Laforge wrote:

> So there's a range of possible Monoid instances for each type, and
> maybe they were chosen by historical happenstance rather than some
> kind of "principle monoid" (is there such a thing?).  Is there a name
> for the thing that's like a monoid, but the operator is commutative
> too?

http://en.wikipedia.org/wiki/Commutative_monoid