
 Crystallographic Topology 101  Orbifold 1 
  Orbifolding is simply the operation of wrapping, or folding in the case of mirrors, to superimpose all equivalent points. 
  There are times when the orbifolding process itself is important, particularly when we are discussing covering spaces, since in that case we may need to unfold the orbifold partially to obtain some other orbifold or fully unfold it to obtain the original space (i.e., the universal cover). 
  The bottom symbol under each orbifold drawing is the international short crystallographic notation for the point group from which the orbifold is derived, with overbars and m's denoting inversion centers and mirrors, respectively, and with 2, 3, 4, and 6 describing the order of rotation axes. 
 www.ornl.gov /ortep/topology/orbfld1.html (2624 words) 
