holds true for each of the p-adic number systems. There is also more recent work on Hilbert's eleventh problem studying when an integer can be represented by a quadratic form. An example is the work of Cogdell, Piatetski-Shapiro and Sarnak. See also Hilbert's problems Notes References Yandell, Benjamin H. The Honors Class: Hilbert's Problems and Their Solvers. Natik: K Peters. Print. 11 Quadratic forms