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1 answer
140 views

Equivalence between choosing a subspace and choosing its orthogonal

Hi, We consider subspaces of $\mathbb{R}^N$. Suppose that we have a property called $\mbox{Prop}$ that apply to subspaces of $\mathbb{R}^N$. That is to say a function from the set of subspaces of $\...
Saïd L.'s user avatar
1 vote
0 answers
501 views

Distribution of random vectors

Two positive numbers $\alpha$ and $\beta$ are given. We are going to describe a process of choosing a random vector on the unit sphere $S$ in $\mathbb R^3$ (given by $x^2+y^2+z^2=1$). A vector $u\in ...
puzzly's user avatar
  • 143
1 vote
1 answer
902 views

Product of densities of a wrapped normal distribution

The density of a wrapped normal distribution is given by $$\frac{1}{\sigma \sqrt{2\pi} }\sum _{k=-\infty }^{\infty }\text{Exp}\left[\frac{-(\theta -\mu -2\pi k)^2}{2\sigma^2}\right]$$ Considering two ...
ostap bender's user avatar
10 votes
2 answers
797 views

Fitting a mesh to a density function

Suppose I have a probability density function defined on a region in the plane (in my case, the pdf is of the form $f(x) = \alpha\|x\|^{-\beta}$, and the region is the unit disk). For large $N$, is ...
John Gunnar Carlsson's user avatar
3 votes
1 answer
528 views

Cover a line segment randomly with smaller line segments

Covering a circle randomly with arcs has been well studied in the past (Geometric Probability - Solomon). But the problem when the circle is changed to a line segment doesn't seem to have been ...
Tianyang Li's user avatar
2 votes
1 answer
319 views

Minimum distance to a sampled point with given pdf

Let $f(x)>0$ be a probability density function defined on the unit square $[0,1]^2$ in $\mathbb{R}^2$. Suppose that we take $N$ independent samples, $X_1,\dots,X_N$, of $f$. Now, sample a point $...
Jennifer Gao's user avatar
11 votes
2 answers
968 views

Clique sizes in a unit disk graph

This is a spiritual successor to a question that Peter Shor answered here: Generalized Euclidean TSP Are there any results known on the asymptotic behavior of clique sizes in a unit disk graph with ...
John Gunnar Carlsson's user avatar
7 votes
3 answers
2k views

Packing density of randomly deposited circles on a plane

Let's say that I have a rectangular two-dimensional surface of bounded dimensions, $[0,A]$ and $[0,B]$: Under "no overlap" constraints, I sequentially deposit circles of radii $r_c$ on this surface,...
user14324's user avatar
  • 309
15 votes
2 answers
755 views

Random noncrossing chords of a circle

Suppose you generate random chords of a circle, with endpoints selected uniformly over the circumference, rejecting any chord that crosses a previously generated chord. The disk is then partitioned ...
Joseph O'Rourke's user avatar
4 votes
1 answer
539 views

Buffon's needles revisited

Hi, I recently came across the famous Buffon's needle problem (http://en.wikipedia.org/wiki/Buffon%27s_needle), and there is no doubt that the problem as well as its answer are elegant. However, the ...
Salil's user avatar
  • 169
47 votes
7 answers
5k views

Intuitive proof that the first $(n-2)$ coordinates on a sphere are uniform in a ball

It is a classical fact that if $(x_1,\ldots,x_n)$ is a random vector uniformly distributed on the sphere $S^{n-1} \subseteq \mathbb{R}^n$, then the random vector $(x_1,\ldots,x_{n-2})$ is uniformly ...
Mark Meckes's user avatar
  • 11.4k
2 votes
2 answers
571 views

The consequence of overlap sharing for the length-distribution of rods randomly placed on a line

Please imagine that one populates a finite line of unit length, or circle with unit length contour (to avoid edge-effects), with $N$ one-dimensional 'rods' such that their LHS-ends, at positions $(p_1,...
10 votes
3 answers
5k views

Mean minimum distance for K random points on a N-dimensional (hyper-)cube

Given K points in a N-dimensional (hyper-)cube with all edges length 1. What is the expected minimal distance between 2 points. I found the 1-dimensional case in this topic: Mean minimum distance for ...
Ingdas's user avatar
  • 371
14 votes
3 answers
4k views

How to generate random points in $\ell_p$ balls?

How do I feasibly generate a random sample from an $n$-dimensional $\ell_p$ ball? Specifically, I'm interested in $p=1$ and large $n$. I'm looking for descriptions analogous to the statement for $p=2$:...
Mitch's user avatar
  • 667

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