F. Li et Zk. Liu, A sufficient condition for a smash product as a transfinite left free normalizing extension and its application, ACTA MATH S, 16(1), 2000, pp. 71-78
In this paper, a sufficient condition is given under which the smash produc
t A#H is a transfinite left, free normalizing extension of an algebra A. Mo
reover, the result is applied to a skew semigroup ring, a skew group ring a
nd the quantum group U-q(sl(2)) such that some properties are shown.