文摘
In this paper we consider PI-algebras A over the real and complex numbers and address the question of whether it is possible to find a normed PI-algebra B with the same polynomial identities as A, and moreover, whether there is some Banach PI-algebra with this property. Our main theorem provides an affirmative answer for this question and moreover we also show the existence of a Banach Algebra with the same polynomial identities as A. As a byproduct we prove that if A is a normed PI-algebra and its completion is nil, then A is nilpotent.