‎"NEUMANN, JOHN von.‎
‎Einige Bemerkungen zur Diracschen Theorie des relativistischen Drehelektrons.‎

‎Berlin, Julius Springer, 1927. 8vo. Contemp. hcloth. Gilt lettering to spine. In: ""Zeitschrift für Physik"" Vol. 48. VIII,891 pp. (Entire volume offered). Neumann's paper: pp. 868-881. A stamp to titlepage. Clean.‎

Reference : 48882

‎First printing of a famous paper in which Neumann extends the relativistic wave equation of the electron set forth by Dirac earlier the same year and Neumann here gives the five fundamental covariants of the Dirac theory.""Von Neumann’s most famous work in theoretical physics is his axiomatization of quantum mechanics. When he began work in that field in 1927, the methods used by its founders were hard to formulate in precise mathematical terms"" ""operator"" on ""functions"" were handled without much consideration of their domain or definition to their topological properties: and it was blithely assumed that such ""operators,"" when self-adjoint, could always be ""diagonalized"" (as in th finite dimensional case), at the expense of introducing ""Dirac functions"" as ""eigenvectors."" Von Neumann showed that mathematical rigor could be restored by taking as basic axioms the assumptions that the states of a physical system were poinds of a Hilbert space and that the measurable quantities were Hermitian (generally unbounded) operators densely efined in that space.""(DSB).‎