In: Statistics and Probability
A polygon is called convex if every line segment from one vertex
to another lies entirely within the polygon. To triangulate a
polygon, we take some of these line segments, which don’t cross one
another, and use them to divide the polygon into triangles. Prove,
by strong induction for all naturals n with n ≥ 3, that every
convex polygon with n sides has a trian-gulation, and that every
triangulation contains exactly n − 2 triangles. (Hint: When you
divide an n-gon with a single line segment, you create an i-gon and
a j-gon for some naturals i and j. What does your strong inductive
hypothesis tell you about triangulations of these
polygons?)