MinBlocks( module, B )
MinBlocks finds the smallest block containing the echelonised basis B
under the action of the G-module module. The block system record
returned has four components: the number of blocks, a block containing
the supplied basis B, a permutation group P which describes the
action of G on the blocks, and a list which identifies the images of
the generators of G as generators of P. For an explanation of this
last component, see ApproximateKernel.
MinBlocks is called by IsPrimitive.
The algorithm is described in [7].
GAP 3.4.4