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2 votes
0 answers
127 views

Error in an argument using spectral theory

Let $Z=\sqrt{2}\mathbb Z$, and consider the sequence on $\mathbb{Z}$ $$\xi(k)= 1_{Z\cap [k,k+1]\neq\emptyset}.$$(remark that the intersection is either empty or with one point.) Thanks to the comments,...
3 votes
1 answer
251 views

Feynman–Kac formula for other operators

I recently came across the Feynman-Kac formula which states that given an open domain $\Omega\in\mathbb{R}^n$ and $f \in L^2(\Omega)$ where $x \in \Omega$ and $t > 0$, then $e^{t\Delta_D}f(x) = ...
6 votes
1 answer
256 views

Perron-Frobenius and Markov chains on countable state space

The following question naturally arises in the theory of Markov chains with countable state space to which I would be curious to know the answer: Let $A:\ell^1 \rightarrow \ell^1$ be a contraction, i....
1 vote
1 answer
173 views

Spectral gap of a Markov chain on the nonnegative integers

Let $\lambda_k,\mu_k\in\mathbb R_{\ge0}$ $(k\ge1)$ be nonnegative real numbers such that $\sum_{k=1}^\infty k\lambda_k<\infty,$ let $S=\mathbb Z_{\ge0}$ be the nonnegative integers, let $T=\mathbb ...
3 votes
2 answers
307 views

Random matrix is positive

This is a follow up question on my previous question here that was on solved in the deterministic setting by Denis Serre, when the perturbation can be separated. Therefore, I decided to split the ...
1 vote
0 answers
59 views

Sturm-Liouville-like Eigenproblem

Consider the piecewise-deterministic Markov process on $\mathbf{R}$ which moves according to the vector field $\phi (x) = 1$, experiences events at rate $\lambda(x) = 1$, and at events, jumps ...
5 votes
0 answers
242 views

Spectral gap for the Brownian motion with drift on a compact manifold

Let $M$ be a compact Riemannian manifold without boundary, $X$ a smooth vector field on $M$. Consider the Brownian motion $t\mapsto B_t$ on $M$ with drift $X$, so that its generator is $L=\Delta +X$. ...
5 votes
1 answer
1k views

Eigenvalue and eigenvector of ergodic Markov operator for continuous space Markov chain

As we know that the transition matrix $P$ of a Markov chain with finite space is a stochastic matrix, and from Perron-Frobenius Theorem, we know that the spectral radius of the matrix $P$ is $1$, and ...