Let 𝑛 be an integer greater than or equal to 3, and let be a Hermitian form ring, where 𝑅 is commutative.
We prove that if 𝐻 is a subgroup of the odd-dimensional unitary group normalised by a relative elementary subgroup , then there is an odd form ideal such that
where if respectively if .
As a consequence of this result, we obtain a sandwich theorem for subnormal subgroups of odd-dimensional unitary groups.
The stable structure of quadratic modules,
Thesis, Columbia University, 1969.
A. Bak and R. Preusser,
The E-normal structure of odd dimensional unitary groups,
J. Pure Appl. Algebra 222 (2018), no. 9, 2823–2880.