  We investigate the exact solution of BCS pairing model using direct
diagonalization of Fock space. By the data analysis and numerical calculation,
we verify the symmetry between energy spectrum of Fock subspaces, obtain the
common structure features of energy gaps and energy bands in Hamiltonian
spectrum of reduced model, propose the formula to estimate the lowest energy
levels in all of the subspaces of reduced model, and suggest a scheme to
estimate the respective energy spectrum which can reveal the structure of
energy spectrum of pairing model.
