Integral representations of unbounded operators by infinitely smooth kernels

Igor M. Novitskiî
2005 Central European Journal of Mathematics  
In this paper, we prove that every unbounded linear operator satisfying the Korotkov-Weidmann characterization is unitarily equivalent to an integral operator in L 2 (R), with a bounded and infinitely smooth Carleman kernel. The established unitary equivalence is implemented by explicitly definable unitary operators.
doi:10.2478/bf02475625 fatcat:z7elp5h64ngi3kbh43oslbbhk4