Re: how can I return nothing?

Tor Rustad <tor_rustad@xxxxxxxxxxx> writes:
[...]
Now, please name a mathematician who think that your "sign of z":

sign(z) = Re(z) / |Re(z)|

is a useful definition.

I can't name one, but it seems that some mathematicians do find it
useful. See <http://en.wikipedia.org/wiki/Sign_function>. No,
Wikipedia is not definitive, but it seems plausible in this case --
and I remember a "signum" function that does just this on my HP 48
calculator.

--
Keith Thompson (The_Other_Keith) kst-u@xxxxxxx <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
.