# Least Required Number for Constructing n-dimensional Convex Hull

Just had learn the concept of Convex set and Convex Hull.

At this point I had figured of my self regarding the question as following:

"Do I always need to have at least $n+1$ number of elements to construct a convex hull which is embedded in $\Bbb R^n$ space?"

This question is not fully elaborated with a commonly accepted terminologies because of lack of my experience in mathematics so will plot more examples to evade elusiveness.

First, If I have 2-dimensional space, which is correspondent to a sheet of paper , I need at least 3 different elements to construct a polygon which requires at least 2-dimensional space to be fully embedded in it(i.e. triangle would be convex hull which is fully embedded into the 2-dimensional plane with least number of elements).

Also, in a similar vein, If I have 3-dimensional space, which is correspondent to $\Bbb R^3$, I need at least 4 elements or points to construct a 3-dimensional object.

Upon this sense I would like to generalize this idea or notion into n-dimensional sense.

However, where do I have to start from to deal with more or equal to 4-dimensional space which is not visualizable to prove this generalization?

Any related concept or already-existing theorem or statement would be also appreciated.

There is such a thing as a simplex, a generalization of triangles, tetrahedra, and so on. The $n$-simplex is the convex hull of $n+1$ points in $\mathbb R^n$. There's a lot more to say about them, but...
• Let me mention one fact about simplices: for any bounded polytope $P$ in $m$ space there is a simplex $S$ in some $n$ space, such that $P$ is the image of $S$ under an affine map. – kimchi lover Aug 21 '17 at 23:49