The Duality Of Geometry. It&039;s sticky (which is the basis of sf class) and it&039;s hidden most of the time, so the user doesn&039;t have to care for it. In geometry, a striking feature of projective planes is the symmetry of the roles played by points and lines in the definitions and theorems, and (plane) duality is the formalization of this concept.

But it&039;s still there, so some functions care about it.

From this fundamental logical duality follow several others In euclidean geometry and in absolute geometry fragments of the principle of duality hold. We have a category of pure duality systems if mor = mord, which intuitively means that duality suffices to define all structures. Sacred geometry and the new science.