Quote:
Are there also convex hulls for any dimension?
From
Convex Hull Wikipedia[
^]a page:
"Formally, the convex hull may be defined as the intersection of all convex sets containing X or as the set of all convex combinations of points in X. With the latter definition, convex hulls may be extended from Euclidean spaces to arbitrary real vector spaces; they may also be generalized further, to oriented matroids."
That's a clue convex hulls exist for arbitrary dimensions (please note, that does not mean I understand it :-) ).
In such Wikipedia page you may also find useful references.