Chow's Theorem for Linear Spaces
Hans Havlicek
TL;DR
The second possibility can only occur when ( P, L ) and ( P ′, L ′) are 3-dimensional generalized projective spaces.
Abstract
If $φ: L\to L'$ is a bijection from the set of lines of a linear space $(P,L)$ onto the set of lines of a linear space $(P',L')$ ($\dim P, \dim P'\geq 3$), such that intersecting lines go over to intersecting lines in both directions, then $φ$ is arising from a collineation of $(P,L)$ onto $(P',L')$ or a collineation of $(P,L)$ onto the dual linear space of $(P',L')$. However, the second possibility can only occur when $(P,L)$ and $(P',L')$ are 3-dimensional generalized projective spaces.
