On Mon, Jan 16, 2023 at 12:08:33AM +0300, Jean Louis wrote:
> * Rudolf Adamkovič <salutis@me.com> [2023-01-15 23:27]:
> > Jean Louis <bugs@gnu.support> writes:
> > 
> > >> (+) ➜ 0
> > >
> > > Why? It is wrong.
> > 
> > In Lisp, the `+' operator returns the sum of the additive identity with all of
> > its arguments.  The additive identity equals zero and you provided zero
> > arguments.  Hence, you get the additive identity.
> 
> Send me references on what is additive identity.

Identity element [0] as defined in group theory [1].

The association of 0 with + and 1 with * runs deeper in maths
than you think.

> Though that it is so, it does not answer why is it so.

Those are, of course, conventions. As whether the natural
numbers begin with 0 or 1. But the above is, AFAIK, most
widespread among mathematicians, wheter the latter is not.

Cheers

[0] https://en.wikipedia.org/wiki/Identity_element
[1] https://en.wikipedia.org/wiki/Group_theory

-- 
t