unit normal vector field造句

in the second part, we investigate the compact submanifolds m with the parallel isoperimetric section in the real space forms rm ( c ) and prove that if there exists a parallel isoperimetric section on m, and the sectional curvature of m is always greater than zero, then m is contained in a hyper-sphere; and get that the gauss curvature of the compact surfaces m with constant mean curvature in constant curvature space r4 ( c ) is always greater than zero, then m is a totally geodesic surface or a sphere, where an isoperimetric on m means a unit normal vector field defined globally on m with m1 ( ) = constant
(2)研究了实空间形式r~m(c)中具有平行等参截面的紧致子流形m，证明了具有一平行等参截面的子流形m，如果m的截面曲率恒正，则m包含在r~m(c)的一个超球面内；对于常曲率空间及r~4(c)中具有常平均曲率的紧致曲面m，如果m的高斯曲率处处大于零，则m或为r~m(c)中的全测地曲面或为一球面。这里m上的等参截面是m上整体定义的单位法向量场，使得m关于它的平均曲率m_1()是常数。
It's difficult to find unit normal vector field in a sentence. 用unit normal vector field造句挺难的