A group theoretic operation which is useful in the study of complex atomic spectra. A plethysm takes a set of functions of a given symmetry type and forms from them symmetrized products of a given degree
and other symmetry type
. A plethysm
(1)
|
satisfies the rules
(2)
|
(3)
|
(4)
|
(5)
|
where is the coefficient
of
in
,
(6)
|
where is the partition of
conjugate to
, and
(7)
|
where is the coefficient of
in the inner product
(Wybourne 1970).