Fh. Lin, GRADIENT ESTIMATES AND BLOW-UP ANALYSIS FOR STATIONARY HARMONIC MAPS, Comptes rendus de l'Academie des sciences. Serie 1, Mathematique, 323(9), 1996, pp. 1005-1008
For stationary harmonic maps between Riemann manifolds, we provide an
essentially necessary and sufficient condition for the uniform gradien
t bounds in terms of the total energies of maps. If the target manifol
d does not carry any harmonic S-2, then the singular set of a stationa
ry map is (n - 4) rectifiable. Various applications and related facts
including their counterparts in the flow case are also addressed.