Re: Comments on Motion 27-A "Decorated Intervals"
On 2011-07-15 18:37:06 -0500, Nate Hayes wrote:
> Vincent Lefevre wrote:
> >I meant: what confidence con brings compared to ndf?
> >
> >Since
> > * one can obtain con for a function that is nowhere defined, and
> > * one can obtain ndf for a function that is not nowhere defined
> > (due to the tracking rules),
> >it seems that there isn't a difference between ndf and con.
>
> If one obtains ndf for a function evaluated over interval box X, then one
> knows with certainty that X is everywhere undefined. This isn't true with
> con.
sqrt(([1,4],saf) Union (Empty,ndf)) = ([1,2],ndf)
but the motion is not clear about Union. If ndf is not propagated,
then the corresponding exception is lost, while "decorations are
properties that carry information on the history of the interval"
(and the motion would need to specify the decoration of the union
of several empty sets).
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)