Re. Curto et C. Hernandez, A JOINT SPECTRAL CHARACTERIZATION OF PRIMENESS FOR C-ASTERISK-ALGEBRAS, Proceedings of the American Mathematical Society, 125(11), 1997, pp. 3299-3301
We prove that a C-algebra A is prime iff sigma(T)((L-a,R-b), A) = sig
ma(a) x sigma(b) for every a,b is an element of A, where sigma(T) deno
tes Taylor spectrum and L-a, R-b are the left and right multiplication
operators acting on A.