Bubbling phenomena of Palais-Smale-like sequences ofm-harmonic type systems

In this paper, we study the bubbling phenomena of weak solution sequences of a class of degenerate quasilinear elliptic systems ofm-harmonic type. We prove that, under appropriate conditions, the energy is preserved during the bubbling process. The results apply tom-harmonic maps from a closed Riemannian manifoldM to a Riemannian homogeneous space, and tom-harmonic maps with constant volumes, and also to certain Palais-Smale sequences.