Curve shortening flow and smooth projective planes

Smooth Projective Planes

Using symplectic topology and the Radon transform, we prove that smooth 4-dimensional projective planes are diffeomorphic to CP. We define the notion of a plane curve in a smooth projective plane, show that plane curves in high dimensional regular planes are lines, prove that homeomorphisms preserving plane curves are smooth collineations, and prove a variety of results analogous to the theory ...

The topology of smooth projective planes

(i) If the (covering) dimension n of the point space ~ is finite, then ~ is a generalized manifold, and N has the same cohomology as one of the four classical point spaces P2 N, P2t~, P2]H or P2 O, and thus n e {2, 4, 8, 16}, cp. L6wen [111. This holds in particular, if the point rows and the pencils of lines are topological manifolds. In this case, the point rows and pencils of lines are n/2-s...

Curve Shortening Flow in a Riemannian Manifold

In this paper, we systemally study the long time behavior of the curve shortening flow in a closed or non-compact complete locally Riemannian symmetric manifold. Assume that we have a global flow. Then we can exhibit a a limit for the global behavior of the flow. In particular, we show the following results. 1). Let M be a compact locally symmetric space. If the curve shortening flow exists for...

Affine and projective planes

Grid peeling and the affine curve-shortening flow

In this paper we study an experimentally-observed connection between two seemingly unrelated processes, one from computational geometry and the other from differential geometry. The first one (which we call grid peeling) is the convex-layer decomposition of subsets G ⊂ Z of the integer grid, previously studied for the particular case G = {1, . . . ,m} by Har-Peled and Lidický (2013). The second...