  In many applications to finite Fermi-systems, the pairing problem has to be
treated exactly. We suggest a numerical method of exact solution based on SU(2)
quasispin algebras and demonstrate its simplicity and practicality. We show
that the treatment of binding energies with the use of the exact pairing and
uncorrelated monopole contribution of other residual interactions can serve as
an effective alternative to the full shell-model diagonalization in spherical
nuclei. A self-consistent combination of the exactly treated pairing and
Hartree-Fock method is discussed. Results for Sn isotopes indicate a good
agreement with experimental data.
