It is possible to model such a system mathematically.

做出这种统的学模型是可能的。

In order to define this irrotationality condition mathematically, let us consider the equation of motion in terms of velocities.

为学上确定此无旋性条件，我们考虑以速度为未知函的运动方程。

CONCLUSIONS: When all other identified risk factors were controlled for mathematically, metastasectomy maintained a significant surial adantage for patients with pulmonary metastatic melanoma.

当其他的鉴别风险因子算术的控制后，转移瘤切除术对有肺转移性黑色素瘤患者仍有显著的生存优势。