Almost subnormal subgroups in division rings with generalized algebraic rational identities

Abstract

In this paper, we study non-central almost subnormal subgroups of the multiplicative group of a division ring satisfying a nonzero generalized rational identity. The main result generalizes Chiba’s theorem on subnormal subgroups. As an application, we get a theorem on almost subnormal subgroups satisfying a generalized algebraic rational identity. The last theorem has several corollaries which generalize completely or partially some previous results.