u-invariant of a field

例句：

1. 1. The u-invariant ofthe field is 0.
   该场的不变量为0。
2. 2. The constants of thefield are crucial for understanding its behavior.
   该场的常数对于理解其行为至关重要。
3. 3. Invariants play a key rolein the study of relativity.
   不变量在相对论研究中起着关键作用。