When Is a Bogolyubov Automorphism Inner?

Abstract

Let $V$ be an infinite-dimensional vector space over a field of characteristic not equal to $2$. Given a nondegenerate quadratic form $f$ on $V$, we consider the Clifford algebra $\mathrm{Cl}(V,f)$. Any orthogonal linear transformation of $V$ extends to a Bogolyubov automorphism of $\mathrm{Cl}(V,f)$. We obtain necessary and sufficient conditions for a Bogolyubov automorphism to be inner.