Re: [Axiom-developer] Issue 336

[Waldek Hebisch]

Martin Rubey wrote:
> Waldek Hebisch <address@hidden> writes:
> I do not understand this. Could you provide an example?
>

Division by unsimplified zero (IMHO the largest single source of
bugs).  
 
> > so the best we can do is to try to be wrong in as rarely as possible.  I do
> > not think we should just disable _all_ unjustified simplifications: it would
> > a hard job and would make Axiom essentially useless (I do want to get rid of
> > unjustified simplifications, but not by disabling them, rather I want to
> > justify then if possible and use conditional expressions otherwise).  Since
> > now we have a lot of unjustified simplifications disabling one of them may
> > just trigger another one, sometimes worse.
> 
> To be honest, I doubt that this is the way to go. I'd rather stay
> correct-correct, and fix things I break doing so in other ways. This should be
> possible, shouldn't it?
> 

Basically I agree.  But do you want to disable division?  That would break
lage part of Axiom.

Concerning binomial, the question is if binomial(n, k) with negative k
is of any use.  If we agree that such binomials are useless it is 
reasonable to make a global assumption that k >= 0 (to some degree it
is similar to current assumption that variables are real). 


-- 
                              Waldek Hebisch
address@hidden