Handouts:
See the
slides
3/11/09: Convex hulls in 2D: last remarks.
Convex polytopes and convex hulls in 3 or more dimensions
The "ultimate convex hull algorithm" takes O(n log h) time (first shown by
Kirkpatrick and Seidel, then drastically simplified by Timothy Chan),
and there is a known lower bound of Omega(n log h), showing that
this is the best you can do if the time bound is written both in
terms of n and h.
Graduate students are expected to understand the algorithm;
undergraduates are expected to know that
it is possible, and this is the best bound achievable in terms of
n and h.
Definition of convex polyhedron. (See Chapter 4, O'Rourke.)
Combinatorics: planar graphs, Euler's formula, linearity of
the number of edges and faces (as a function of n, the number of
vertices).
Discussion of Platonic Solids.
Introduction to convex hulls in 3 or more dimensions.
In 3D, the CH can be found using divide-and-conquer in time O(n log n).
We state that the time it takes to compute a hull in d dimensions
for d>=4 is O(n^{floor(d/2)}), which is the worst-case complexity
of the output size (ie., the hull may have that many faces).