#Example: "PqDescendants-1" . . . based on manual example
#(demonstrates `PqDescendants' usage)
#vars: F, a, b, procId, G, des;
#options: 
F := FreeGroup( "a", "b" ); a := F.1; b := F.2;
G := PcGroupFpGroup( F / [ a^2, b^2, Comm(b, a) ] );
#alt: do
#procId := PqStart( G );
#alt: sub <procId> for <G>
des := PqDescendants( G : OrderBound := 6, ClassBound := 5 );
Length(des);
List(des, Size);
List(des, d -> Length( PCentralSeries( d, 2 ) ) - 1 );
