Jun 24, 2019 · 图像以上为 凸集 的就是凸函数，如开口向上的二次函数，英文里叫Convex或concave up，反过来就是凹函数，英文叫Concave或concave down，这是国际上的定义。 国内大部分经济学 …

If you know the standard English meaning of the words convex and concave, you can remember that for a convex function it is the epigraph that is convex, and for a concave function it is the epigraph that is …

那么我们来讲凸函数（convex function）为什么叫做是凸（convex）的： 这是因为凸函数与凸集（convex set）有联系，而凸集的定义没有争议。 1. 凸函数与凸集通过 sublevel sets 这个概念联系起 …

Convex function Quasiconvex function Pseudoconvex function 在R上考虑就很容易理解。在凸要求不高过xy连线的地方，拟凸只要求不高过xy中较大者，所以凸蕴含拟凸；而伪凸则要求，“切线”“指哪”函 …

Aug 3, 2023 · 英文世界中，一般分为Convex Function和Concave Function 通常意义上，前面是向下凹，后面是向上凹。 一个 助记 是con后面跟的是V，形状就和V类似。 否则，则形状就是倒着的 Λ 而 …

Nov 26, 2018 · I have now corrected the errors in my question (mixed up strictly concave and concave) and broadly ask about when I can use the second derivative to prove concavity (as is done to show …

Functions whose negative is convex occur frequently and "concave [function]" came into use as a convenient description of this situation. The linguistic logic was clear enough to make this …

Sep 5, 2015 · If you determine that the function is convex or concave each entails the latter their (quasi counterpart) concavity implies quasi concavity. Likewise with convexity.

Real valued function $\neq$ extended real value function (the former is the setting setting of the question and my answer, the latter is your setting). In any case, your epigraph isn't even convex,...

Concave implies subadditive [duplicate] Ask Question Asked 13 years ago Modified 4 years, 1 month ago