If an n-th order linear
ordinary differential equation Ly = 0 is disconjugate, then the sign of the Green’s
functions is well known. In this work, it is only supposed that Ly = 0 is
(i1,⋯,ik)-disconjugate for certain values of i1,⋯,ik, and the sign of the Green’s
functions for certain multipoint problems is shown to be the same as when Ly = 0 is
disconjugate. The results extend earlier ones on two-point problems due to
Peterson. The proofs simplify Peterson’s arguments in a way such that the
analysis of two-point problems is not only easier but carriers over to multipoint
problems.