Extended real arithmetic (was Re: inf - inf = 0 ??)



  On 9/13/2010 12:27 PM, Richard Hennessy wrote:
> The good thing is that an extension to Maxima that handles inf, und, 
> ind and minf would force the user to think.  About what I am not sure 
> but some users don't want to think about that, they just want the 
> answer in the quickest and easiest way possible.  That results in 
> letting the computer do the thinking and the user learns nothing.  I 
> am guilty of this too.
>
> Rich
>
Such an extension would require rewriting the simplifier.  It would not 
be an extension the way adding rules to a previously unknown function 
name could add
functionality of (say) taking derivatives etc.   It would require 
replacing existing code to check for strange objects including und, inf, 
intervals.

I agree that users often just want the answer and don't want to think 
more than necessary.  That's a reasonable (first) approach,  though.

RJF