  Relationships are obtained connecting the two-nucleon overlap function of the
eigenstates in the (A-2) particle system with the asymptotic behavior of the
two-body density matrix for the ground state of the A-particle system.This
makes it possible to calculate the two-body overlap functions, spectroscopic
factors and separation energies on the basis of a realistic two-body density
matrix. The procedure can be used in describing the (e,e'NN) and (\gamma, NN)
reactions where the two--body overlap functions are a key ingredient in the
analysis.
