[Haskell-cafe] Re: Num instances for 2-dimensional types

[David Menendez]

On Wed, Oct 7, 2009 at 12:08 PM, Ben Franksen <ben.franksen at online.de> wrote:
>
> More generally, any ring with multiplicative unit (let's call it 'one') will
> do.

Isn't that every ring? As I understand it, the multiplication in a
ring is required to form a monoid.

-- 
Dave Menendez <dave at zednenem.com>
<http://www.eyrie.org/~zednenem/>