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39 votes
5 answers
3k views

Surfaces filled densely by a geodesic

Which smooth, closed surfaces $S \subset \mathbb{R}^3$ have no single geodesic $\gamma$ that fills $S$ densely? Say a geodesic $\gamma$ "fills $S$ densely" if the closure of the set of points ...
Joseph O'Rourke's user avatar
29 votes
2 answers
1k views

Is every closed curve in 3D a geodesic on a genus-0 surface?

Let $\gamma$ be a smooth, closed, unknotted curve embedded in $\mathbb{R}^3$. Q. Does there always exist a smooth, embedded, genus-zero surface $S \subset \mathbb{R}^3$ such that $\gamma$ is a (...
Joseph O'Rourke's user avatar
23 votes
2 answers
1k views

Can we make distances in a finite subset of a manifold whatever we want?

Given a connected smooth manifold $M$ of dimension $m>1$, points $p_1,\dots,p_n\in M$ and positive values $\{d_{i,j};1\leq i<j\leq n\}$ satisfying the strict triangle inequalities $d_{i,j}<d_{...
Saúl RM's user avatar
  • 10.6k
12 votes
3 answers
988 views

Primary definition of a geodesic

I am wondering if there is a sense in which one of these definitions for a geodesic on a smooth Riemannian manifold is primary to the other. A geodesic has acceleration zero, i.e., it is self-...
Joseph O'Rourke's user avatar