(2+1)-Gravity Solutions with Spinning Particles
  We derive, in 2+1 dimensions, classical solutions for metric and motion of two or more spinning particles, in the conformal Coulomb gauge introduced previously. The solutions are exact in the $N$-body static case, and are perturbative in the particles' velocities in the dynamic two-body case. A natural boundary for the existence of our gauge choice is provided by some ``CTC horizons'' encircling the particles, within which closed timelike curves occur. 
M. Ciafaloni and P. Valtancoli