Rosenberg, Milton - In: Journal of Multivariate Analysis 8 (1978) 2, pp. 295-316
Let p, q be arbitrary parameter sets, and let 9 be a Hilbert space. We say that x = (xi)i[epsilon]q, xi [epsilon] 9, is a bounded operator-forming vector ([epsilon]9Fq) if the Gram matrix <x, x> = [(xi, xj)]i[epsilon]q,j[epsilon]q is the matrix of a bounded (necessarily = 0) operator on 6, the Hilbert...</x,>