The automorphisms of non-defective orthogonal groups in characteristic 2 (Q1075438)

It is shown that the automorphism group of an orthogonal group \(O(F^ n,q)\) (or the derived group thereof) on an n-dimensional vector space (where \(n\geq 6\), \(n\neq 8)\) over a field F of characteristic 2 (but \(F\neq F_ 2)\) with respect to a non-defective quadratic form q is isomorphic to \(P\Gamma O(F^ n,q)\).