Coherent quantum-mechanical climb motion of a dislocation pair involve
s exchanges of an array of particles. For electrons in a magnetic fiel
d this motion becomes possible near odd denominator filling factors, t
he pair is liberated and its energy is decreased, consistent with the
lowering of the activation energy in recent transport measurements by
Jiang et al. This decrease also provides a mechanism of re-entrant mel
ting via spontaneous generation of dislocation pairs.