UV decomposition theory is an efficient method dealing with the second order expansion of nonsmooth functions. It is obtained via the U Lagrangian that a function f has second order expansions along smooth trajectories.

• UV 分解理论是处理非光滑函数的二阶展开的有效方法 ；它借助于U 拉格朗日函数 ；得到函数在一个光滑轨道上的二阶展开式 .