Editing Convex set (section)

=== Blaschke-Santaló diagrams ===
The set  <math>\mathcal{K}^2</math>  of all planar convex bodies can be parameterized in terms of the convex body [[Diameter of a set|diameter]] ''D'', its inradius ''r'' (the biggest circle contained in the convex body) and its circumradius ''R'' (the smallest circle containing the convex body). In fact, this set can be described by the set of inequalities given by<ref name=":0">{{Cite journal|last=Santaló|first=L.|date=1961|title=Sobre los sistemas completos de desigualdades entre tres elementos de una figura convexa planas|journal=Mathematicae Notae|volume=17|pages=82–104}}</ref><ref name=":1">{{Cite journal|last1=Brandenberg|first1=René|last2=González Merino|first2=Bernardo|date=2017|title=A complete 3-dimensional Blaschke-Santaló diagram|url=http://mia.ele-math.com/20-22|journal=Mathematical Inequalities & Applications|language=en|issue=2|pages=301–348|doi=10.7153/mia-20-22|issn=1331-4343|doi-access=free|arxiv=1404.6808}}</ref>
<math display=block>2r \le D \le 2R</math>
<math display=block>R \le \frac{\sqrt{3}}{3} D</math>
<math display=block>r + R \le D</math>
<math display=block>D^2 \sqrt{4R^2-D^2} \le 2R (2R + \sqrt{4R^2 -D^2})</math>
and can be visualized as the image of the function ''g'' that maps a convex body to the {{math|'''R'''<sup>2</sup>}} point given by (''r''/''R'', ''D''/2''R''). The image of this function is known a (''r'', ''D'', ''R'') Blachke-Santaló diagram.<ref name=":1" />
[[File:Blaschke-Santaló_diagram_for_planar_convex_bodies.pdf|alt=|center|thumb|673x673px|Blaschke-Santaló (''r'', ''D'', ''R'') diagram for planar convex bodies. <math>\mathbb{L}</math> denotes the line segment, <math>\mathbb{I}_{\frac{\pi}{3}}</math> the equilateral triangle, <math>\mathbb{RT}</math> the [[Reuleaux triangle]] and <math>\mathbb{B}_2</math> the unit circle.]]
Alternatively, the set  <math>\mathcal{K}^2</math> can also be parametrized by its width (the smallest distance between any two different parallel support hyperplanes), perimeter and area.<ref name=":0" /><ref name=":1" />