A k-pyramid Pk is the convex hull of a (k - 1)-polytope Q and a point x ∉ aff Q. Find a formula for each of the following in terms of fj (Q), j = 0,,,,,,, n - 1.
a. The number of vertices of Pn : f0(Pn).
b. The number of k-faces of Pn : fk (Pn), for 1 ≤ k ≤ n - 2.
c. The number of (n - 1)-dimensional facets of Pn : fn-1(Pn).