I would like to know if anyone needs the following (strange) feature
of 'Depth( <g> )', where <g> is an agword: If <g> is the identity
'Depth' will return zero and *not* the composition length + 1 of the
parent of <g>. This is due to historic reasons, because in the first
versions of GAP there existed an identity without parent group.
If nobody uses this feature I will change this in GAP 3.2.