Re: Comments on decoration ill, intersection and union
On 2012-12-14 08:04:56 -0600, Nathan T. Hayes wrote:
> Vincent Lefevre wrote:
> > On 2012-12-13 16:29:52 -0600, Nathan T. Hayes wrote:
> > > If we evaluate the range of the intersection of X and Y, then
> > > g([0,1] intersect [2,3])
> > > = g(([0,1],DAC) intersect ([2,3],DAC))
> > > = g((Empty,DAC)) // Empty input!!!
> > > = (Empty,DAC)
> >
> > But the initial input is [0,1], which is not empty ([2,3] can be
> > seen as a constant or another input, depending on the context).
> > One gets Empty only after the intersect operation, and since this
> > is after an operation, Empty cannot be an input.
>
> Precisely. This is why the (Empty,DAC) result is not meaningless: it may
> imply the input was nonempty even though the result is empty.
But what does it mean exactly?
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Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
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