square root expression simplification



Am Montag, den 01.11.2010, 08:15 +0000 schrieb Leo Butler:
> 
> <snip>
> 
> I'd like to suggest an alternative, which I do so in the blissful
> ignorance of the simplifier. I'd like to suggest that instead of
> butting heads over which is the right way to do simplification, we
> improve the configurability and/or modularity of the simplifier, 
> so that the user can choose the right simplification policy.
> 
> What I have in mind includes:
> 
> 1. assemble several 'standard' or useful configurations of the
> simplifier and create a single function that lets the user
> select configurations, or create new ones.
> 
> 2. add health warnings in the documentation to clarify what is
> meant by simplification.
> 
> I tend to think that simplification is more a question of implementing
> a *policy* as opposed to getting a mathematically correct answer. 
> What I mean is that most users, most of the time, want Maxima's
> simplifier to do what they would do (e.g. sqrt(4) -> 2), and they
> tend to get upset when this doesn't happen -- even when they know
> better and know it is 'wrong'. So we should have a simplifier policy
> ('high_school_algebra') that implements this. But it would be
> wrong to commit the Maxima simplifier to this policy in the large.
> 
> Leo

Yes, that is my opinion, too. I agree with your suggestions. I think it
is not to difficult to get a consistent implementation of some
simplification policies. It is more difficult to define these policies.

Dieter Kaiser