Re: CVS commit: src/games/factor

[Dennis den Brok <d.den.brok%uni-bonn.de@localhost>]

Aleksej Saushev <asau%inbox.ru@localhost> schrieb:
> I know at least one school that doesn't teach mathematical analysis
> using Cauchy-style definitions prefering to start from topology,
> I know another (quite large!) school that introduces filters as soon as
> possible to avoid dealing with handful of special cases, I was taught
> Robinson (non-Archimedean) analysis in parallel to classical one.

AFAIK, this is also referred to as "non-standard analysis"...
Shouldn't NetBSD rather adhere to standards?

> And as far as I remember there do exist schools that consider 1 as prime
> number. Note that I didn't proclaim this ex cathedra and performed some
> analysis of this possibility, while you didn't dare to bring anything to
> support your point of view.

There doesn't seem to be a good reason relevant to the purpose of
a small tool included in an operating system, apart from that,
indeed, most people do not consider 1 prime, because that is what
they were taught at school and in most courses at university, or
it is most convenient in their particular field of mathematical
research.

The manpage included in NetBSD less-or-equial 5.x does not even
mention the word "prime", by the way, and so far negative integers
have, contrary to what the manpage says, been rejected, so I suggest
the wording to be changed such that "factor" is supposed to return
a minimal factorization of a non-negative integer by numbers not
further non-trivially decomposable.
In particular, "factor x" yields "x: x" for x \in \{0,1\}.

If absolutely required, I would let the manpage state that for
negative integers their absolute values are factored as for
non-negatives and then "x: -1 ${factors_of_|x|}" is returned.

Maybe this can be agreed upon?

Regards,

Dennis den Brok