“…Let H be a complex Hilbert space with inner product ·, · , B(H) and Obviously, if k = 1, we get the classical numerical range W (A) and the numerical radius w(A) of A. If (c 1 , ..., c k ) = (1, ..., 1), W c (A) and r c (A) reduce to k-numerical range and k-numerical radius of A, respectively ( [4,8,10]). Numerical range (radius) and c-numerical range (radius) are important concepts and have many applications in pure and applied mathematics, especially in quantum control and quantum information.…”