Preliminaries on Classical Groups
摘要
In this chapter we first define the symplectic, orthogonal and unitary groups. Building on work of Britnell and Milnor, we then give necessary and sufficient criteria for an element X of the general linear group \({\mathrm {GL}}(V)\) to preserve a non-degenerate alternating, hermitian or quadratic form on V , in terms of the elementary divisors of \(\,X\) .