The bidual of a radical operator algebra can be semisimple (Q2346666)

\textit{S. L. Gulick} claimed in [ibid. 18, 121--137 (1966; Zbl 0198.17901)] that the intersection of a Banach algebra \(A\) with the radical of its bidual \(A^{**}\) is the radical of \(A\). The author of the paper under review gives a simple counterexample to that claim. Further, the author looks at the papers which have referenced the above mentioned paper and he points out that he did not find a case in which Gulick's wrong result is used.