complex conjugation

Richard B. Kreckel kreckel at
Sun Nov 23 23:06:51 CET 2003

Hi Chris!

On Sun, 23 Nov 2003 chrisd at wrote:
> I would say that the default behaviour of functions should be
> conjugate(f(arg)) --> f(conjugate(arg)). Then there should be a new
> function option to specify a different behaviour for your particular
> function. I was wondering a bit about what to do with the log. For that
> function the default behaviour is okay, except for the real negative axis.

Of course, exactly the same problems arise on other (analytic) functions
with branch cuts.  Take for instance asin(x) for real x where |x| > 1.
But that shouldn't stop you.

> I would say that just bluntly using the default behaviour, ignoring
> possible problems, would be best.

I guess that's right.  What about non-analytic functions?  We don't seem
to have many, though, yet (just abs and csgn).

Richard B. Kreckel
<Richard.Kreckel at GiNaC.DE>

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