1. Introduction.- 2. Brillouin-Wigner perturbation theory.- 3. The many-body problem in atoms and molecules.- 4. Brillouin-Wigner methods for many-body systems.- 5. Summary and prospects.
1. Introduction.- 2. Brillouin-Wigner perturbation theory.- 3. The many-body problem in atoms and molecules.- 4. Brillouin-Wigner methods for many-body systems.- 5. Summary and prospects.