N | Number of the time points on the main loop of time | Contractions of the time points | Total number of the perturbation terms SN (see Table 1) |
1 | 1 + 0 | no contractions | 1 |
2 | 1 + 1 | no contractions | 1 |
3 | 1 + 2 |
|
|
4 | 1 + 3 | , , , |
|
|
|
|
|
5 | 1 + 4 | , , , |
|
|
| , , , |
|
|
| , , |
|
|
| , , , |
|
|
| , |
|
6 | 1 + 5 | , , , , , |
|
|
| , , , , , |
|
|
| , , , |
|
|
| , , , |
|
|
| , , , |
|
|
| , , , |
|
|
| , , , |
|
|
| , , , , |
|
|
| , , , , |
|
|
| , , , , |
|
|
| , , , |
|