Re: Natural data type ?

["Chad R. Meiners" <crmeiners@hotmail.com>]

I seriously doubt that someone made a random decision.  There are many
reasons to define N to include zero, for instance, the positive integers can
easily represented as Z^+ while the negative integers may be represented as
Z^-.   There is a very nice symmetry with these representations of disjoint
sets.  It doesn't make sense to define the natural numbers to simply be the
set of positive integer because you then have two competing names for the
same set.  Thus, it is better for the natural numbers (N) to be a different
set from the positive integers (Z^+).  Since zero isn't positive, this
leaves N as the only candidate for containing zero.

Very likely, whoever made this decision for Ada's data type of natural and
positive had a similar rational reason for making this choice.  I just don't
see the designers flipping a coin or playing paper, scissors, rock to
determine which data type gets zero ;)  I wasn't around during Ada's initial
design process; perhaps someone on comp.lang.ada was, and they know why or
who made this decision or even if the decision was contested.

-CRM

"Peter I. Hansen" <pih@oek.dk> wrote in message
news:3CA25342.1080906@oek.dk...
> Chad R. Meiners wrote:
>
> >No misprint.  The natural numbers can be define as containing zero as
well
> >as not containing zero.  I know a good deal of mathematicians that define
N
> >to include zero; I also know a good deal of mathematicians that prefer N
to
> >only include positive whole numbers (zero is neither positive nor
negative).
> >
> >-CRM
> >
> So, your answer is that someone just made a random decision ?
>
> /Peter
>