  We study strongly correlated electrons on a kagome lattice at 1/6 and 1/3
filling. They are described by an extended Hubbard Hamiltonian. We are
concerned with the limit |t|<<V<<U with hopping amplitude t, nearest-neighbor
repulsion V and on-site repulsion U. We derive an effective Hamiltonian and
show, with the help of the Perron-Frobenius theorem, that the system is
ferromagnetic at low temperatures. The robustness of ferromagnetism is
discussed and extensions to other lattices are indicated.
