q- Deformed Boson Expansions
  A deformed boson mapping of the Marumori type is derived for an underlying $su(2)$ algebra. As an example, we bosonize a pairing hamiltonian in a two level space, for which an exact treatment is possible. Comparisons are then made between the exact result, our q- deformed boson expansion and the usual non - deformed expansion. 
S.S. Avancini, F.F. de Souza Cruz, J.R. Marinelli, D.P. Menezes and   M.M. Watanabe de Moraes