Resumen de Stable sandwich classification theorem for classical-like groups

Zuhong Zhang

• Let H denote a subgroup of the unitary group U(R, ?) which is normalized by EU(J, GJ) for some form ideal (J, GJ) of a commutative form ring (R, ?). We prove that H satisfies a �sandwich� property, i.e., there exists a form ideal (I GI) such that for some form ideal (I : J7, O). This answers a conjecture of Bak (1967) in the stable case.