Skip to main content

All Questions

Filter by
Sorted by
Tagged with
1 vote
0 answers
76 views

Translate of a geodesic that goes through a fixed point on $\mathbb{H}$

Consider the complex upper half plane $\mathbb{H}$ with the hyperbolic geometry. Fix a point $z \in \mathbb{H}$ and also a geodesic $c$. I want to find a hyperbolic translation $\gamma c$ passes that ...
0 votes
1 answer
175 views

Reference request: How to construct a diffeomorphism between point clouds

I'm interested in the following question: Given two sets $S = \{x_1, ..., x_N\}$ and $T = \{y_1, ..., y_N\}$ each consisting of $N$ distinct points in $\mathbb{R}^n$, how can we construct a ...
3 votes
2 answers
157 views

Finding a point inside a surface

I have a triangulation of a surface without boundary in $\mathbb{R}^3$. The triangulation gives a unit normal pointing outwards for each triangle. I need to find some point in the interior of the ...
1 vote
0 answers
87 views

On vertices on convex smooth closed surfaces

Question: Given a smooth, convex, closed surface. How would one find points on it with the property: the average of the geodesic distances from that point to all other points on the surface (the ...
8 votes
1 answer
316 views

What is the form of the $(v_0,v_1)$-pizza curve?

Assume that there are two (competing) pizza houses situated at the points $0$ and $1$ on the complex plane. These pizza houses can deliver pizza to points of the plane with the largest velocities $v_0$...
2 votes
1 answer
223 views

Discrete curve-shortening flow – numerical implementation

I need to investigate the properties of open curves which evolve according to the standard curve-shortening flow (Wikipedia link), but with fixed extremes as boundaries (si it should converge to the ...
6 votes
5 answers
4k views

Formulas for equidistant curves

I'm trying to draw on the computer a curve that keeps always the same distance(given as parameter) from a given curve. I know the formula for the given curve. I tried moving perpendicular to the first ...
11 votes
5 answers
1k views

Segments of Voronoi Diagrams on smooth manifolds. Are they geodesics?

Let $S$ be a patch of a smooth 2-manifold in $\mathbb{R}^3$, and pick two distinct points $a,\ b \in S$. Let $c$ be the set of points on $S$ equidistant to $a$ and $b$, where distance is defined by ...
2 votes
2 answers
399 views

Computer algebra for calculating curvature when the tensor metric is very big

Is there a computer algebra method to compute the curvature of a Riemannian metric on the plane when the metric tensor has long entries $E,F,G$ The computation by hand is very ...
5 votes
0 answers
1k views

Reach of manifold vs. $C^k$-manifold

The reach $\tau_M$ of a manifold $M$ is the largest number such that any point at distance less than $\tau_M$ from $M$ has a unique nearest point on $M$. This concept seems quite related to the local ...
0 votes
1 answer
124 views

Triangle inside the Closed Curve

For any piece wise smooth, simple closed curve $\gamma$ in the Euclidean plane $E^2$ and fix a point $G$ inside the area circled by $\gamma$. Show: There exists three points $A,B$ and $C$ on the $\...
6 votes
1 answer
148 views

Does a minimum area disk that is bounded by a cycle $C$ continuously deform in $R^3$ as $C$ moves in $R^3$?

Let $C_1=(v_1,v_2,\ldots,v_{i-1},v_i)$ and $C_2=(v_1,v_2,\ldots,v_{i-1},v'_i)$ be two cycles that are drawn in $R^3$ in the shape of an unknot (not knotted) with straight line segments as their edges (...
0 votes
0 answers
108 views

conformal deformation with fixed boundaries

For a flat plane with certain boundary, e.g., a rectangular patch, is it possible to conformally displace or deform such patch to a curved bump with exact same boundary? In this thesis, Dr. Keenan ...
8 votes
1 answer
1k views

Dubins car shortest paths: Decidable?

A Dubins car follows a Dubins path in $\mathbb{R}^2$, with constant wheel speed and limited turning radius. It is known that the shortest Dubins path in the absence of obstacles follows circular arcs ...
2 votes
1 answer
586 views

Inverse Problem for Pullback

Let $M$ and $N$ be smooth manifolds and $T: M \to N$ be a smooth map. Let $ \mathcal{F}(M,\mathbb{R})$ (resp.$ \mathcal{F}(N,\mathbb{R})$) denote the space of smooth functions from $M$ (resp. $N$) ...
1 vote
0 answers
91 views

Representing a Pullback as an Infinite Matrix

Let $M$ and $N$ be manifolds and let $T: M \to N$ be a bijective map. Let $ \mathcal{F}(M,\mathbb{R})$ (resp.$ \mathcal{F}(N,\mathbb{R})$) be the space of all functions from $M$ (resp. $N$) to $\...
8 votes
2 answers
362 views

Computational methods for dealing with geometrically complicated solid boundaries in fluid-air interface problems

Hello, I am a PhD student who does not have extensive computational experience seeking advice from those experienced with computational modelling as to which method would be most appropriate for ...
4 votes
3 answers
919 views

Area-preserving map between rectangles and fat polygons

Are there any well-known continuous area-preserving maps between fat convex polygons and fat rectangles? Specifically, given a fat convex polygon $C$, is there a natural way to choose a fat rectangle ...