Ground state energy of metallic ferromagnet in a generalized Hubbard   model
  In the present work ferromagnetic ordering in the Hubbard model generalized by taking into account the inter-atomic exchange interaction and correlated hopping in partially filled narrow band is considered. In the case of weak electron-electron interaction the ground state energy and condition of ferromagnetic state realization are found using the Green function technique. The obtained results indicate the important role of correlated hopping. 
L. Didukh, O.Kramar, Yu. Skorenkyy (Ternopil State Technical   University, Ukraine)