| Contents |
| A linear bounded operator G in a complex Hilbert space H is said to be symmetrizable by a bounded positive self-adjoint operator S if SG is self-adjoint. We study the spectrum of non- compact symmetrizable operators G with non injective symmetrizers S. We analyze its essential spectrum and also its isolated eigenvalues outside its essential disc. In particular, we give variational characterizations of such eigenvalues. Finally, we show how these tools apply to spectral analysis of neutron transport equations with partly elastic scattering operators. |
|