# Representing Graham Scan Mathematically

I am aware the convex hull algorithm known as Graham Scan can be computed by sorting the derived vectors from points given in a 2D plane. One then iterates through a series of Cross Product calculations to find the determinant of a pair of vectors derived from the sequence of given points. This determine whether to move clockwise of counter clockwise with respect to drawing a convex hull in an efficient manner.

How do I represent that using sigma notation?

I was thinking along the line of: $\sum_{i=1}^{N} Det(V_i,V_{i+1})...Det(V_n,V_{n-1}),$ where $V_i$ is the initial vector.

• Welcome to CS.SE! Represent what using "sigma" notation? Why do you want to represent it using "sigma" notation? What's the point? How are you going to use any answer you get? Why have you rejected the approach you already considered? – D.W. Sep 24 '16 at 0:38
• What do you mean "sigma notation"? The summation? – Raphael Sep 24 '16 at 9:07
• Sigma notation = summation. Why? because I think it best represents looping through vectors to find the determinant of a pair of vectors. I have not rejected anything, merely looking to confirm that the approach is sound. Is it then? – Mr. Concolato Sep 30 '16 at 11:50