Hybridizing the skyrmion with an anti-de-Sitter bag
  I discuss a phenomenological model of the nucleon in which a small anti-de Sitter bag is placed into the Skyrmion configuration. Such a bag has a timelike boundary and allows naturally the Cheshire Cat Principle. Very important in this model is the membrane of the bag, the 3-dimensional time-space manifold S^{1}\times S^{2}, in which topological techniques will come into play 
H.C. Rosu