Comparison of the structure of Jastrow and exact many fermion theories

The structure of Jastrow and exact many body theory (in expS-form) are compared. The results are: 1. The correct linked clusters can be computed in terms of Jastrow correlation functions; 2. especially the Bethe-Goldstone (or defect) wave functions are defined uniquely and differ from those used in former comparisons; 3. one should use the (Jastrow) “model energy” instead of the expectation value thereby avoiding violation of the Pauli principle and some problems with higher order terms.