@article {15232,
	title = {THE NUMERICAL RANGE OF ELEMENTARY OPERATORS},
	journal = {Integr. equ. oper. theory},
	volume = {43},
	year = {2002},
	pages = {248-252},
	abstract = {For n-tuples A = (At, ..., AN) and B = (BI, ..., Bn) of operators on aHilber! spaceH, let RA,B denote the operator on L(H) defined by RA,B(X) = ~i=1AiX Bi. Inthis paper we prove thatco c~i13i : (a,,..., an) C W(A), (131, ..., 1~) e W(B) C Wo(RA,B)where W is the joint spatial numerical range and W0 is the numerical range. Wewill show also that this inclusion becomes an equality when I~A,B is taken to bea generalized derivation, and it is strict when RA,B is taken to be an elementarymultiplication operator induced by non scalar self-adjoints operators.},
	author = {Seddik. A}
}
