[Haskell-beginners] Expressing the idea of a group in Haskell

[Daniel Fischer]

On Wednesday 16 March 2011 13:41:25, Patrick LeBoutillier wrote:
> Hi,
> 
> Math newbie here: what's the difference between a group and a monoid?

In a group, there are inverses. A group is a monoid in which every element 
has an inverse.

So, natural numbers with addition: monoid, no inverses for n /= 0
Integers with addition: group