On Tue, Jan 17, 2023 at 02:20:45AM +0000, Drew Adams wrote:
> > > The use of `apply', pointed out by Anders, speaks
> > > directly to "any number of arguments".  It applies
> > > a function (e.g. `+') to "any number of arguments",
> > > which are passed as a list.
> > 
> > Any number means also no argument? To me that is not clear.
> 
> That's why I pointed out that _zero is a number_.

Those are big words :-)

Minus one is also a number, but we'd be hard pressed to come
up with a function taking minus one arguments. Three-quarters,
the square root of two and pi are numbers. Arguably, "the"
Chaitin constant [1] (actually there are many of them)is also
a number.

I think the manual wants to say "natural number" and just
says "number", but that's OK, because it is directed at humans,
and we humans are usually better at disambiguating given a
context than at staying awake in front of long and boring texts.

Arguably, "zero or more" might be clearer here, but I don't
know (after all, the square root of two is bigger than zero,
too).

Now mathematicians don't agree on whether zero is a natural
number. The faculty I studied in started counting from zero,
but I've seen faculties which count from one. I once asked
a friend of mine teaching at one uni, and he told me faculties
having a strong mathematical logic department tended to start
with zero.

So zero may be a number or not, at least if you read "number"
as "natural number", and you ask a mathematician :)

Cheers

[1] There are uncountably many horrible monsters in the
    real numbers:
    https://en.wikipedia.org/wiki/Chaitin%27s_constant

-- 
t