 In other words, a polycyclic generating system of a Sylow "p"-subgroup can be found by starting from any "p"-subgroup "H" (including the identity) and taking elements of "p"-power order contained in the normalizer of "H" but not in "H" itself.The algorithmic version of this (and many improvements) is described in textbook form in , including the algorithm described in .These versions are still used in the GAP computer algebra system.