Integral representations of closed operators as bi-Carleman operators with arbitrarily smooth kernels

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/70848In this paper, we characterize all closed linear operators in a separable Hilbert space which are unitarily equivalent to an integral bi-Carleman operator in $L_2(R)$ with bounded and arbitrarily smooth kernel on $R^2$. In addition, we give an explicit construction of corresponding unitary operators. The main result is a qualitative sharpening of an earlier result of [5].LaTeX file, 10 pagesSpectral TheoryFunctional Analysis47B38; 47G10; 45P05Integral representations of closed operators as bi-Carleman operators with arbitrarily smooth kernelstext