Description of Singularities

• Self-intersections of surface (interatomic axis intersects probe sphere, discontinuous normal vector)
  
  
• Types
  
  
  • Free saddle cusps (pairs i,j)
    
    
  • Holes (triplets i,j,k) - interpenetration of two sph. triang., open and closed holes
    
    
  • General concave edges