Re: Notions of Type

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Fri, 18 Aug 2006 14:14:24 GMT
Message-ID: <4XjFg.51105$pu3.597633@ursa-nb00s0.nbnet.nb.ca>

Marshall wrote:

> erk wrote:
>

>>Marshall wrote:
>>
>>>erk wrote:
>>>
>>>>Sorry if this is obvious to everyone else, but does an algebra include
>>>>only operations defined on values of the type in question?
>>>
>>>Yes.
>>
>>I read elsewhere (and I'm not saying it's right) that an algebra could
>>be defined as a closure over a set of types. Is that untrue?

>
> I'm not exactly sure what that would mean.
>
> In fact, I lack a pithy definition of algebra. (And worse, there are
> many senses of the word.) But one thing is common, and that
> is a datatype and binary operators that are closed over that
> datatype. Sometimes associativity of those operators is
> considered a requirement, but it seems a distant second
> to closure.

Why binary? I sincerely doubt that requirement. Received on Fri Aug 18 2006 - 09:14:24 CDT