20D20 20D10 13 finite group 7 20D15 6 saturated formation 4 Finite group 3 maximal subgroup 3 supersoluble group 3 05C25 2 20B35 2 20E22 2 20E28 2 20F16 2 Cayley graphs 2 Schmidt subgroup 2 Sylow \(p\)-subgroup 2 Sylow subgroup 2 \(K\)-lattice saturated formation 2 \(\cal F\) -critical group,\(\cal F\) -maximal subgroup 2 \(\cal F\)-hypercentre 2 \(\pi\)-Hall subgroup 2 \(\pi\)-soluble group 2 \(\sigma\)-nilpotent group 2 \(c\)-normal subgroup 2 \(p\)-supersoluble groups 2 \(s\)-permutable group 2 boundary condition 2 cover-avoidance property 2 derived \(\pi\)-length 2 group base 2