1. Any classical two-body problem to be converted into an equivalent one-body problem . 2. Thouless has made many important contributions to the theory of many-body problems . 3. This is useful when attempting to solve problems like the two-body problem . 4. In a gravitational two-body problem with negative energy both bodies follow barycenter. 5. Any classical two-body problem to be converted into an equivalent one-body problem. 6. Therefore, it is necessary to study the possible singularities of the 3-body problems . 7. However, eventually research determines that there is no solution to the three-body problem . 8. He studied a many-body problem on the collective oscillations of a quantum-mechanical system. 9. According to McGinn, such philosophical questions include the mind-body problem , empirical. 10. Lagrangian points are the constant-pattern solutions of the restricted three-body problem .