Let R be a semiprime ring with extended centroid C and with Q its Martindale symmetric ring of quotients. Suppose that δ: R → R is a C-integral derivation. For a subring A of Q, let A~((δ)) denote the subring of constants of δ in A. We prove that R~((δ)) and Q~((δ)) satisfy the same polynomial identities with coefficients in C. In particular, R~((δ)) is not nil of bounded index.
展开▼
