| 边界 | 必要条件 |
|
|
|
|
|
| 自由 | 无 | 0 | 0 | 0 | 0 | 0 |
| 软简支 |
| 0 | 1 | 1 | 0 | 0 |
| 简支 |
| 1 | 1 | 1 | 0 | 1 |
| 固支 |
| 1 | 1 | 1 | 1 | 1 |