1. CMB 2010 (vol 53 pp. 737)
|On the Negative Index Theorem for the Linearized Non-Linear SchrÃ¶dinger Problem|
A new and elementary proof is given of the recent result of Cuccagna, Pelinovsky, and Vougalter based on the variational principle for the quadratic form of a self-adjoint operator. It is the negative index theorem for a linearized NLS operator in three dimensions.