T. Yanai, AUTOMORPHIC-DIFFERENTIAL IDENTITIES AND ACTIONS OF POINTED COALGEBRASON RINGS, Proceedings of the American Mathematical Society, 126(8), 1998, pp. 2221-2228
In this paper, we prove the following two results which generalize the
theorem concerning automorphic-differential endomorphisms asserted by
J. Bergen. Let R be a ring, R-F its left Martindale quotient ring and
U a right ideal of R having no nonzero left annihilator. (1) Let C be
a pointed coalgebra which measures R such that the group-like element
s of C act as automorphisms of R. If R is prime and xi.U = 0 for xi is
an element of R#C, then xi.R = 0. Furthermore, if the action of C ext
ends to R-F and if xi is an element of R-F#C such that xi.U = 0, then
xi.R-F = 0. (2) Let f be an endomorphism of R-F given as a sum of comp
osition maps of left multiplications, right multiplications, automorph
isms and skew-derivations. If R is semiprime and f(U) = 0, then f(R) =
0.