397 398 HANS ARWED KELLER complete fields; the valuations in question have infinite rank. Investigations on the particular properties of these spaces E lead, via the fundamental theorem of projective geometry, to maps /: E -> E which are semilinear, i.e. linear up to some fixed automorphism T of the base field K. It is then crucial to know that τ and T" 1 are continuous. We refer to [2] for a comprehensive account on orthomodular spaces.