Residually *-Abelian Valuation with Residue Characteristic Not 2

Abstract

We are given a division ring D with involution (*) and with a *-valuation V such that V(sx − xs) > V(sx), for all nonzero elements x, s of D with s = s*. Let χ denote the characteristic of the residue class division ring associated with V. We reported in Theorem 3.2.5 Part 4 in [3] that, in the case χ = 0, either D is a standard quaternion division algebra or else D contains no algebraic elements other than the scalars. In this article, we carry out a generalization of the preceding theorem to the case χ ≠ 2. Our results are fairly complete in the finite dimensional case, and generalize theorems of, notably, J. Graeter and A. I. Lichtman, in the infinite dimensional case.