At 00:00 +0200 98/08/04, Felix Schroeter wrote:
>On Mon, Aug 03, 1998 at 04:18:49PM +0200, Hans Aberg wrote:
>> So, why not add a type "Complexify(R)" of a ring R to Haskell?
>
>Note that you can't divide in a ring. A type class *roughly* corresponding
>to a ring is probably Num.
Sure you can divide in a ring (in mathematics): Given an associative ring
$R$ with an unit, define the set $R^\x$ (writing \x = \times) of elements
with (two-sided) inverse. Then those can be divided.
Fields (such as the rationals, reals and the complex numbers) have $R^\x
= R - \{0\}$, so a lot more elements can be divided in those than say the
ring of integers which have the set of invertible elements $\{1, -1\}$.
Hans Aberg
* Email: Hans Aberg <mailto:[EMAIL PROTECTED]>
* Home Page: <http://www.matematik.su.se/~haberg/>
* AMS member listing: <http://www.ams.org/cml/>
