Re: '0' replacement

[Josef Urban <urban@ktilinux.ms.mff.cuni.cz>]

> It is Czeslaw Bylinski that argued against HIDDEN. Let him make his point.
> 
> The real problem is the identification of the empty set and 0. Not the
> representation. I would propose first to substituted for d238 '{}' (as a
> functor symbol, not functor brackets). Some people claim that it looks a bit
> childish. ? Then it should be put on the BOOLE vocabulary, if course. And '0'
> may be introduced later as a synonym for '{}'.

When I wrote about placing it in HIDDEN, I supposed the "0=={}" is already
decided matter. If not, I would be also quite against it, because in my
opinion, if we omit set theorists, very little mathematicians need the
fact that zero (only as a natural number) is usually modelled as the empty
set. 
On the contrary, quite often "0" is a common notation for other things
(e.g. some neutral or minimal element).
So I would also be for the "{}" symbol ( and if someone wants to make his
article illegible, he can use "0" as a synonym :-) ).

Josef Urban