Making Peace with the Projective Plane

(johndcook.com)

15 points | by ibobev 2 hours ago

2 comments

  • abetusk 1 minute ago
    The motivation is better than most, trying to treat infinity as just another case instead of an exceptional one, but, to me at least, it still feels like a "hack" to put in a third dimension and then insist on dividing by it to reproject whenever you want to do anything useful.

    I'm a little used to the trick but it'd be nice to give some deeper motivation of why the trick works in the first place and why this particular representation.

  • nh23423fefe 1 minute ago
    The only time i've understood applications of projective geometry was seeing rotations and translations unified using exponentials of bivectors. I still dont get homogenous coords. Like i get how f(lambda*x)=lambda^n*f(x) and that means f is like a homomorphism but i've never solved any problem sets and understood why one would do this in the first place.