of a group
A subgroup series of ,
where each subgroup is a normal subgroup of . The quotient groups are called factors, and the number is called the length of the subnormal series. Infinite subnormal series have also been studied (see Subgroup system). A subnormal series that cannot be refined further is called a composition series, and its factors are called composition factors.
A subnormal series is also called a subinvariant series.
|[a1]||M. Hall jr., "The theory of groups" , Macmillan (1959) pp. Sect. 8.4|
Subnormal series. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Subnormal_series&oldid=19288