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Dear GAP-Forum

Alexander Konovalov wrote:

I need to calculate conjugacy classes of subgroups of order 16 (or of all

orders not greater then 16) in PcGroup of order 2^15.In the manual there are two special methods for subgroup lattice

calculation which allows to state size of desired subgroups:

- LatticeByCyclicExtension

- SubgroupSolvableGroup (in combination with ExactSizeConsiderFunction)which one could be more efficient in this case ?

LatticeByCyclicExtension works from the bottom up, SubgroupsSolvableGroup

from the top down. In general I would expect that

- The method in which subgroups are substantially ``closer'' will work

better. In this case this would be cyclic extension. Please note that you

can give a exclusion function to speed calculations up by eliminating

groups which are too big.

(In general SubgroupsSolvableGroup is more efficient than

LatticeByCyclicExtension if the group is solvable.)

Best,

Alexander Hulpke

-- Colorado State University, Department of Mathematics,

Weber Building, 1874 Campus Delivery, Fort Collins, CO 80523-1874, USA

email: hulpke@math.colostate.edu, Phone: ++1-970-4914288

http://www.math.colostate.edu/~hulpke

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