Thompson's theorem for compact operators and diagonals of unitary operators

Abstract

As applications of Kadison’s Pythagorean and carpenter’s theorems, the Schur–Horn theorem, and Thompson’s theorem, we obtain an extension of Thompson’s theorem to compact operators and use these ideas to give a characterization of diagonals of unitary operators. Thompson’s mysterious inequality concerning the last terms of the diagonal and singular value sequences plays a central role.

Publication
Indiana University Mathematics Journal, vol. 67 (1), pp. 1–27

Related