  The paper examines part of the ground state diagram of the extended Hubbard
model, with the on-site attraction U<0 and intersite repulsion W>0 in the
presence of charge density waves, superconducting and $\eta$-superconducting
order parameters. We show the possibility of the stabilization of the mixed
state, with all three nonzero order parameters, in the model with nearest
neighbor interactions. The other result of the paper is application of the
exact solution of the Schrodinger equation for the two electron bound state, as
an additional bound for the phase diagram of the model, resulting in the
partial suppression of the superconducting state of the s-wave symmetry, in
favor of the normal state phase.
