This monthly journal, begun in 1950, is devoted entirely to research in pure and applied mathematics, principally to the publication of original papers of moderate length. A section called Shorter ...

Journal of Operator Theory, Vol. 58, No. 2 (Fall 2007), pp. 415-440 (26 pages) In this paper the well-known result that a definitizable operator in a Krein space remains definitizable after a finite ...

a self-adjoint linear operator to ensure that the energy levels are all real and that the time evolution of the system is unitary (conservation of the total probability). A few years ago, it was ...