On the methods of Rayleigh-Ritz-Weinstein
Cahït Arf · Proceedings of the American Mathematical Society · 1952
The Rayleigh-Ritz-Weinstein methods are concerned with the connection between eigenvalues of a completely continuous symmetric operator in a Hilbert space and the eigenvalues of its projection into a subspace X of H such that the difference Hex-x is finitedimensional. In this paper we extend some of the known results of Weinstein and Aronszajn to more general symmetric operators and to the case where x is not necessarily finite-dimensional. We consider a continuous symmetric operator Q and the solutions of the equation