[Haskell-cafe] Equality of functions

[Thomas Davie]

Woops... scratch my stupitity... we could of course discover the test 
to be false on an extremely large integer.

Bob

--
God is real... Unless you define it as an integer.
On 1 Dec 2004, at 01:19, Thomas Davie wrote:

> On 1 Dec 2004, at 01:06, Bernard Pope wrote:
>
>> On Tue, 2004-11-30 at 13:52 +0000, Jules Bean wrote:
>>> In the same sense, you could try
>>>
>>> (map f [1..]) == (map g [1..])
>>>
>>> and it will return False quickly if they are different, but it will 
>>> run
>>> forever if they are the same.
>>
>> For some very generous definition of "quickly" :)
>
> With respect to the fact that we do not know how fast f or g run, the 
> only way to define quickly in this sense is relative to how fast f and 
> g run.  We can return False from (map f [1..]) == (map g [1..]) with a 
> constant time slow down from returning False from (f 1) == (g 1).  I'd 
> call constant time reasonably 'quickly'.
>
> Bob
>
> --
> What is the internet?
> It's the largest equivalence class in the reflexive transitive 
> symmetric closure of the relationship "can be reached by an IP packet 
> from". -- Seth Breidbart
>
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