Fully isotopic model of fragmentation

A general model for the fragmentation of a two-component or bipartite system (e.g., protons and neutrons) is proposed and solved exactly. The extension of this model to any number of components is also shown to be exactly solvable. A connection between this model and the permutation group is discussed and used to obtain closed-form solutions. The notion of isotopic equivalence is defined in order to evaluate the equivalence of these models to earlier one-component models. All the one-component models considered in earlier papers are shown to be equivalent to a particular subclass of two-component models. A simplified model applicable to the case of nuclear fragmentation is introduced and analyzed. Modifications to this model to include effects such as pairing and Coulomb interactions are discussed