1. CMB 2011 (vol 56 pp. 102)
 Kong, Qingkai; Wang, Min

Eigenvalue Approach to Even Order System Periodic Boundary Value Problems
We study an even order system boundary value problem with
periodic boundary conditions. By establishing
the existence of a positive eigenvalue of an associated linear system
SturmLiouville problem, we obtain new conditions for the boundary
value problem to have a positive solution. Our major tools are the
KreinRutman theorem for linear spectra and the fixed point index theory
for compact operators.
Keywords:Green's function, high order system boundary value problems, positive solutions, SturmLiouville problem Categories:34B18, 34B24 

2. CMB 2009 (vol 40 pp. 416)
3. CMB 1998 (vol 41 pp. 23)
 Clemence, Dominic P.

Subordinacy analysis and absolutely continuous spectra for SturmLiouville equations with two singular endpoints
The GilbertPearson characterization of the spectrum is established
for a generalized SturmLiouville equation with two singular
endpoints. It is also shown that strong absolute continuity for the
one singular endpoint problem guarantees absolute continuity for the
two singular endpoint problem. As a consequence, we obtain the result
that strong nonsubordinacy, at one singular endpoint, of a particular
solution guarantees the nonexistence of subordinate solutions at both
singular endpoints.
Categories:34L05, 34B20, 34B24 
