Published online by Cambridge University Press: 22 January 2016
The P-harmonic boundary ΔP and the P-singular point s of a Riemannian manifold R have been shown to play an important role in the study of bounded energy-finite solutions of Δu = Pu (Nakai-Sario [7], Kwon-Sario [4], Kwon-Sario-Schiff [5]). The objective of the present paper is to establish, in terms of ΔP and s, properties of unbounded energy-finite solutions (PE-functions) and of limits of decreasing sequences of positive PE-functions (-functions). Also, PE- and -minimal functions will be discussed.