<p>Hi: The connection between convex sets and convex ( and concave ) functions is that convex ( and concave ) functions should be defined on convex sets because, if the functions are defined on sets that are not convex, then there may be points on the set where the convex (and concave ) function is not defined.</p>

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2021-09-30T15:00:56.200Z
2022-12-12T15:42:07.617Z
2022-12-12T15:42:07.617Z
mark leeds
<p>I want to understand why do we have to define a function on convex set before we define concavity or convexity.</p>
<p><a href="https://mjo.osborne.economics.utoronto.ca/index.php/tutorial/index/1/CVN/t#d:CvxSet" rel="nofollow noreferrer">https://mjo.osborne.economics.utoronto.ca/index.php/tutorial/index/1/CVN/t#d:CvxSet</a></p>
<p>I am reading this and I dont understand why they explained convex sets before explaining concavity and convexity.</p>

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2021-09-30T06:12:00.707Z
@markleeds Please post answers as answers.
Giskard
<mathematical-economics><definition>
Convex sets definition
Damien
# Convex sets definition

(Asked by: username_0 on 2021-09-30)

I want to understand why do we have to define a function on convex set before we define concavity or convexity.

<https://mjo.osborne.economics.utoronto.ca/index.php/tutorial/index/1/CVN/t#d:CvxSet>

I am reading this and I dont understand why they explained convex sets before explaining concavity and convexity.

**Tags:** mathematical-economics, definition
> **Comments:**
> **username_1**: @markleeds Please post answers as answers.  

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## 1 answers

### Answer by username_2 on 2021-09-30. Score: 3

Hi: The connection between convex sets and convex ( and concave ) functions is that convex ( and concave ) functions should be defined on convex sets because, if the functions are defined on sets that are not convex, then there may be points on the set where the convex (and concave ) function is not defined.


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