[Haskell-cafe] Functional progr., images, laziness and all therest

Brian Hulley brianh at metamilk.com
Thu Jun 22 10:16:57 EDT 2006

minh thu wrote:
> 2006/6/22, Brian Hulley <brianh at metamilk.com>:
>> Jerzy Karczmarczuk wrote:
>>> Brian Hulley wrote:
> [snip]
>>> y IS NOT a longer list than yq, since co-recursive equations without
>>> limiting cases, apply only to *infinite* streams. Obviously, the
>>> consumer of such a stream will generate a finite segment only, but
>>> it is his/her/its problem, not that of the producer.
>> I still don't understand this point, since y = (a*x0 : yq) so surely
>> by induction on the length of yq, y has 1 more element?
> y and yq are infinite...

But how does this change the fact that y still has 1 more element than yq?
yq is after all, not a circular list.
I don't see why induction can't just be applied infinitely to prove this.

Regards, Brian.

Logic empowers us and Love gives us purpose.
Yet still phantoms restless for eras long past,
congealed in the present in unthought forms,
strive mightily unseen to destroy us.


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