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15 votes
1 answer
616 views

Acute triangles in "obtuse" polygons?

Let $P$ be a convex polygon. Suppose every interior angle of $P$ is obtuse. Is it always the case that there exist three vertices $p, q, r$ of $P$ such that $\triangle pqr$ is acute? I conjecture ...
Scattering State's user avatar
9 votes
1 answer
424 views

Hamiltonian circuit

Let us consider a disk with one labelled point on the boundary and $n$ labelled points in the interior. Let T be a triangulation of the whole disk with vertices on the labelled points such that T ...
Anonymous's user avatar
  • 828
5 votes
1 answer
261 views

Do random triangulation edge-flips maintain randomness?

Let $S$ be a fixed set of $n$ points in the plane in general position. Let $T$ be a triangulation of $S$, (somehow) selected uniformly at random from all triangulations of $S$. (There are an ...
Joseph O'Rourke's user avatar
4 votes
2 answers
481 views

Complexity of Random Delaunay Triangulation in 3D

My question: Is the number of cells in a three-dimensional Poisson-Delaunay triangulation with $n$ vertices $\mathcal O(n)$ with probability one? which is equivalent to the question Is the ...
Dahn's user avatar
  • 141
4 votes
1 answer
323 views

What properties does generalized Delaunay triangulation have?

Suppose that instead of the usual circle, we pick some other convex set D and make the Delaunay triangulation of a finite planar point set with respect to this set, i.e. connect two points if there is ...
domotorp's user avatar
  • 19k
3 votes
1 answer
2k views

practical algorithm for constrained triangulation in two dimensions?

I'm looking for an algorithm that is easy to implement in practice (resulting in small amount of code), preferably incremental. As far as I know, the biggest problem with incremental constrained ...
nem's user avatar
  • 131
2 votes
1 answer
115 views

mean length of the non-crossing graphs on n points

My original question is rather vague so I'll start with a precise example and then indicate possible generalisations. Given a n-tuple $x=(x_1,\dots,x_n)$ in, say, a square with side-length $1$ in the ...
kaleidoscop's user avatar
  • 1,352
2 votes
0 answers
23 views

What is known about $\operatorname{card}_E(\mathrm{MST}\cap\mathrm{MWT})$?

It is a wellknown fact of computational geometry that the edges of Minimum-weight Spanning Tree are also found in the Delaunay Triangulation of a planar pointset $\mathcal{P}$, i.e. $\operatorname{...
Manfred Weis's user avatar
  • 13.2k
1 vote
1 answer
73 views

Partitioning polygons into obtuse isosceles triangles

Ref: Partitioning polygons into acute isosceles triangles Partition of polygons into 'strongly acute' and 'strongly obtuse' triangles https://math.stackexchange.com/questions/1052063/...
Nandakumar R's user avatar
  • 5,979
1 vote
1 answer
51 views

On triangulations and "coverage" of circumcircles

Let $P$ be a convex quadrilateral defined by four vertices $a$, $b$, $c$, and $d$. Suppose that the circumcircle of $\triangle abd$ contains $c$.* Let $D(\triangle abc)$ to denote the area enclosed by ...
Scattering State's user avatar
1 vote
0 answers
22 views

Calculating an optimal scaling factor for Delaunay triangulations

consider a finite set $\mathcal{P}(x,y)=\lbrace(x_1,y_1),\dots,\,(x_n,y_n)\rbrace$ of points in the Euclidean plane and let $\mathrm{DT}(x,y)$ be the Delaunay triangulation of $\mathcal{P}(x,y)$ ...
Manfred Weis's user avatar
  • 13.2k
1 vote
0 answers
62 views

What are some other methods for partitioning an n-dimensional space based on a set of points in that space?

So this is a very general question, but I'm curious if there are any other methods for partitioning an n-dimensional space based on the location of a set of points, either randomly chosen or specified,...
Fran's user avatar
  • 11
1 vote
0 answers
259 views

How to do an elevated 2D Delaunay triangulation?

This is what I call an elevated Delaunay triangulation: This is also called a 2.5D Delaunay triangulation. To do it, I simply perform an ordinary 2D Delaunay triangulation with the (x,y)-coordinates, ...
Stéphane Laurent's user avatar
0 votes
0 answers
37 views

Restrictions on crossing edges in Delaunay triangulations

what can be said about crossing edges in Delaunay triangulations, i.e. about pairs of edges that constitute to the heaviest perfect matching int the $K_4$ induced by the quadruplet of adjacent ...
Manfred Weis's user avatar
  • 13.2k