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[Axiom-developer] [#180 bug #9216 differentiating sums with respect to a
[Axiom-developer] [#180 bug #9216 differentiating sums with respect to a bound is wrong] Old Discussion
Thu, 23 Jun 2005 03:28:25 -0500
> > > #3148: bug #9216 differentiating sums with respect to a
> > bound is wrong [A]
> > in my opinion correct beyond doubt.
> In the patch report you wrote:
> "Mathematically axiom produces correct output now, however
> I'm not sure whether my patch is best possible.
> Maybe there should be a function D in OutputForm that displays
> unevaluated differentiation. Also, I find it ugly to use the
> raw %diff operator in COMBF. Furthermore, is it necessary to
> substitute a dummy variable for the variable of differentiation?"
> I am concerned that this is another case of a "quick fix" for
> which we should consider a more general solution of the kind
> that you suggest above.
In this case the situation is a tiny little bit different, since here also
Axioms internal representation is wrong. Worse: the design of Axioms Algebra
currently doesn't provide "unevaluated differentiation". Obviously, it was
thought that anything can be differentiated. In fact, I'm almost sure that
attempting to differentiate a sum by one of its bound should signal an error,
because it is impossible to assign a mathematically correct meaning to it. In
this sense, I'd suggest that we aim to reach consensus until end of January.
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- [Axiom-developer] [#180 bug #9216 differentiating sums with respect to a bound is wrong] Old Discussion,