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In mathematics, specifically group theory, finite groups of prime power order , for a fixed prime number and varying integer exponents , are briefly called ''finite'' ''p-groups''. The ''p''-group generation algorithm by M. F. Newman 〔 〕 and E. A. O'Brien 〔 〕 〔 〕 is a recursive process for constructing the descendant tree of an assigned finite ''p''-group which is taken as the root of the tree. ==Lower exponent-''p'' central series== For a finite ''p''-group , the lower exponent-''p'' central series (briefly lower ''p''-central series) of is a descending series of characteristic subgroups of , defined recursively by and , for . Since any non-trivial finite ''p''-group is nilpotent, there exists an integer such that and is called the exponent-''p'' class (briefly ''p''-class) of . Only the trivial group has . Generally, for any finite ''p''-group , its ''p''-class can be defined as . The complete lower ''p''-central series of is therefore given by , since is the Frattini subgroup of . For the convenience of the reader and for pointing out the shifted numeration, we recall that the (usual) lower central series of is also a descending series of characteristic subgroups of , defined recursively by and , for . As above, for any non-trivial finite ''p''-group , there exists an integer such that and is called the nilpotency class of , whereas is called the index of nilpotency of . Only the trivial group has . The complete lower central series of is given by , since is the commutator subgroup or derived subgroup of . The following Rules should be remembered for the exponent-''p'' class: Let be a finite ''p''-group. :# Rule: , since the descend more quickly than the . :# Rule: If , for some group , then , for any . :# Rule: For any , the conditions and imply . :# Rule: Let . If , then , for all , in particular, , for all . 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「P-group generation algorithm」の詳細全文を読む スポンサード リンク
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