📘 projective geometry

1. **Problem statement:** (i) Find the equation of the line through points $[1,2,3]$ and $[1,1,1]$ in $\mathbb{RP}^2$.

1. **Problem Statement:** (i) Given four points A, B, C, D in a projective plane, no three collinear, consider lines AB, BC, CD, DA. Show that if lines AB and BC have a common poin

1. **Problem Statement:** Show that any two lines $\ell_1$ and $\ell_2$ in a projective plane have the same number of points. 2. **Key Idea:** We first prove there exists a point $