楊氏定理：如果N個變數的函式f(X)有連續二階偏微分，則交叉偏微分（混合偏微分）相等。
基本介紹
- 中文名：楊氏定理
- 外文名：Young`s Theorem
- 具體：數學定理
- 公式：f "ij(x) = f "ji(x)
楊氏定理Young`s Theorem
英文定義：
Let f be a differentiable function of n variables. If each of the crosspartials f "ij and f "ji exists and is continuous at all points in some open set S of values of (x1, ..., xn) then
f "ij(x1,..., xn) = f "ji(x1,..., xn) for all (x1,..., xn) in S.
中文定義：
即：
f "ij(x) = f "ji(x)
