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From: "Richard Fateman" <fateman at cs.berkeley.edu>
Sent: Wednesday, September 08, 2010 4:54 PM
To: "Richard Hennessy" <rich.hennessy at verizon.net>
Cc: <maxima at math.utexas.edu>
Subject: Re: [Maxima] inf - inf = 0 ??
> On 9/8/2010 12:21 PM, Richard Hennessy wrote:
>> I think the user should know better.
> There is substantial evidence that this is not always true :)
Agreed.
I don't think trying to decide if this inf is the same infinity as that one (whatever that means assuming it can even be
defined) is the issue.
limit(expr1,x,a)-limit(expr2,x,a) is not always an operation on numbers, since it can be shown that infinity is not in
the real number system or the complex number system. Perhaps the answer could be put in quotes when it is not a number.
Rich
>
> If an expression parses", something (meaningful, error, whatever) is computed.
> And maybe returned.
>
> That includes inf-inf.
>
>
>