A postscript to my last note:

CompositionSeriesSolvablePermGroup has the same difficulty that
SubnormalSeriesPPermGroup has. The TrivialSubgroup in its else branch
creates subnormal subgroups whose element lists only contain (), so that
IsSubgroup and its derivatives report that these subgroups have no subgroups
other than the trivial one.

Charley

wright@math.uoregon.edu

Charles R.B. Wright
Department of Mathematics
University of Oregon
Eugene, OR 97403