max(), sum(), next()

[Manu Hack]

On Thu, Sep 4, 2008 at 4:25 PM, castironpi <castironpi at gmail.com> wrote:
> On Sep 4, 2:42 pm, bearophileH... at lycos.com wrote:
>> David C. Ullrich:
>>
>> > At least in mathematics, the sum of the elements of
>> > the empty set _is_ 0, while the maximum element of the
>> > empty set is undefined.
>>
>> What do you think about my idea of adding that 'default' argument to
>> the max()/min() functions?
>>
>> Bye,
>> bearophile
>
> For max and min, why can't you just add your argument to the set
> itself?
>
> The reason max([]) is undefined is that max( S ) is in S.

It makes sense.

>The reason sum([]) is 0 is that sum( [ x ] ) - x = 0.

It doesn't make sense to me.  What do you set x to?