[Haskell-cafe] Re: 0/0 > 1 == False

Jonathan Cast jonathanccast at fastmail.fm
Sat Jan 12 13:01:55 EST 2008


On 12 Jan 2008, at 1:45 AM, Achim Schneider wrote:

> Kalman Noel <kalman.noel at bluebottle.com> wrote:
>
>> Achim Schneider wrote:
>>> whereas lim( 0 ) * lim( inf ) is anything you want
>>
>> Indeed I suppose that »lim inf«, which is a notation I'm not familiar
>> with, is not actually defined to mean anything?
>>
> It's an ad-hoc expression of "as the slices approach zero size, their
> number approaches infinity". It's more an observation than anything
> else. I have no idea how a professional mathematician would formalise
> it.

I suspected as much.

You mean that, for any extended real number z, two sequences of real  
numbers xn and yn may be chosen so that lim(xn) = 0, lim(yn) = inf,  
and lim(xn * yn) = z.

jcc


>
>
> -- 
> (c) this sig last receiving data processing entity. Inspect headers  
> for
> past copyright information. All rights reserved. Unauthorised copying,
> hiring, renting, public performance and/or broadcasting of this
> signature prohibited.
>
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe



More information about the Haskell-Cafe mailing list