8
votes
1answer
171 views
Variant of an Expander graph: Probability that S random points cast a shadow/projection of size at most S/2 on each face of a cube.
Consider an integer cube of size $\sqrt{k} \times \sqrt{k} \times \sqrt{k}$, where $k$ is an asymptotically large perfect square number. Place k points in this cube at uniformly ra …
0
votes
1answer
75 views
Distance between poisson points in two disjoint unit discs
Two disjoint unit discs $D_1$ and $D_2$. Inside them there are random poisson points with intensity $\lambda$. For a given real $r>0$, what is the probability that there exist a po …
4
votes
1answer
103 views
Nontrivial lower bounds on Cheeger inequalities for Markov chains
For a reversible Markov chain $X_{t}$ on $\mathbb{R}^{n}$ with transition kernel $K$ and stationary distribution $\pi$, it is well-known that the `spectral gap' (basically, the siz …
1
vote
0answers
107 views
Random walk conditioned on sum and last step
Can anyone help with the following (slightly weird) random walk question? I have a random walk starting at $X_0 = 1 = S_0$ where the steps $X_i$ are independent uniform random vari …
1
vote
1answer
75 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 se …
-1
votes
0answers
141 views
Calculating probability of some
I want to estimate exponentially the following probability:
1
vote
0answers
171 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 …
1
vote
1answer
250 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 …
-2
votes
0answers
141 views
Expected value of the smallest point in a plane
Hi,
Suppose i have n (two dimensional) points randomly chosen on a plane.
Both x and y dimensions are intervals [0, 1).
What is the expected size of the kth smallest item?
Note: …
5
votes
2answers
302 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). …
3
votes
1answer
233 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 …
3
votes
1answer
181 views
Distribution of shapes of Delaunay triangles
People haven't been rushing in to answer this question I asked on stackexchange yesterday.
The way I phrased it initially was this: Does anyone know the probability distribution o …

