J. Cruz-sampedro, Exact asymptotic behavior at infinity of solutions to abstract second-order differential inequalities in Hilbert spaces, MATH Z, 237(4), 2001, pp. 727-735
We prove a conjecture of Agmon on the unique continuation "at infinity" of
solutions to certain second-order differential inequalities in Hilbert spac
es. Our result extends previous work of Jager.