On the hopficity of the polynomial rings

In this paper we prove that if a ringR satisfies the condition that for some integern > 1,a ⁿ =a for everya inR, thenR a hopfian ring implies that the ringR T] of polynomials is also hopfian. This generalizes a recent result of Varadarajan which states that ifR is a Boolean hopfian ring then the ringRT] is also hopfian. We show furthermore that there are numerous ringsR satisfying the hypothesis of our theorem which are neither Boolean nor Noetherian.