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  1. 凸凹函数到底怎么定义? - 知乎

    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 …

  2. 为什么数学概念中,将凸起的函数称为凹函数? - 知乎

    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 …

  3. Defintion of strictly concave - Mathematics Stack Exchange

    Nov 26, 2018 · How do I show that if a function satisfies f(αx + (1 − α)y)> αf(x) + (1 − α)f(y) with 0 <α <1, it is true that (assuming it exists) the second derivative f ″ (x) <0. I can see this is true visually in a …

  4. mnemonic - How to remember which function is concave and which …

    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 …

  5. 凹凸函数的图像是怎样的?经济学和数学上定义为什么不一样? - 知乎

    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 而国内汉语世界, …

  6. soft question - Why does "convex function" mean "concave *up ...

    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 …

  7. What is the geometrical difference between concave function and ...

    Oct 21, 2019 · A line is concave, but not strictly concave. Consequently, the graph of a concave function can include linear segments, but the graph of a strictly concave function cannot contain a linear …

  8. Proving a function is quasi-concave - Mathematics Stack Exchange

    Oct 29, 2020 · The function (x1,x2) ↦ x1 (x 1, x 2) ↦ x 1 is an affine function, and hence is concave (and convex). Summing two concave functions produces a concave function, and every concave …

  9. Concave implies subadditive - Mathematics Stack Exchange

    Concave implies subadditive [duplicate] Ask Question Asked 12 years, 11 months ago Modified 4 years ago

  10. 凸函数凹函数的中英文定义倒置? - 知乎

    凸函数凹函数的中英文定义倒置? 凸函数的英文是concave function;凹函数的英文是convex function...但是其实concave的英文翻译是凹,convex的… 显示全部 关注者 6 被浏览