Hi Dieter,
Continuing my exploration of Michael Wester's
examples, is the following:
------------------------------
Maxima 5.22.1 http://maxima.sourceforge.net
using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (a.k.a. GCL)
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
"2010-11-04"
(%i1) sqrt (exp(z));
(%o1) %e^(z/2)
(%i2) expr : sqrt(exp(z)) - exp(z/2);
(%o2) 0
(%i3) [sqrt (exp(%i*2*%pi)), exp(%i*%pi)];
(%o3) [1, -1]
---------------------------------------------------
According to Wester, the simplification Maxima does with
sqrt ( exp (z) ) is true if and only if Im(z) lies in the
set of intervals ...., (-5 pi, -3 pi), (- pi, pi), (3 pi, 5 pi),......
Otherwise, the automatic simplification (using principle
value conventions ) is - exp(z/2), as shown in %o3 above.
Ted Woollett