Search Results
Search type | Search syntax |
---|---|
Tags | [tag] |
Exact | "words here" |
Author |
user:1234 user:me (yours) |
Score |
score:3 (3+) score:0 (none) |
Answers |
answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 |
Views | views:250 |
Code | code:"if (foo != bar)" |
Sections |
title:apples body:"apples oranges" |
URL | url:"*.example.com" |
Saves | in:saves |
Status |
closed:yes duplicate:no migrated:no wiki:no |
Types |
is:question is:answer |
Exclude |
-[tag] -apples |
For more details on advanced search visit our help page |
Dynamical systems on measure spaces, invariant measures, ergodic averages, mixing properties.
1
vote
Accepted
Robustness of ergodic dynamical systems
Yes. Let $\nu$ be a probability measure on $[0,1]$. Let $T$ be the left shift on a sequence space $X:=[0,1]^{\mathbb N}$ equipped with the product $\sigma$-field and the product measure $\mu:=\nu^{\ma …
1
vote
Ergodicity question
It is true that a system is ergodic if (and only if) every measurable function constant along trajectories is globally constant almost everywhere. For indicator functions this is just the usual defini …
1
vote
Sets of invariant measures of Markov operators
A sufficient condition: Commuting Markov operators will have a common invariant measure by https://en.wikipedia.org/wiki/Markov%E2%80%93Kakutani_fixed-point_theorem .
See https://projecteuclid.org/do …
5
votes
Accepted
von Neumann ergodic theorem for $L_p$
False for p infinite. True for finite. See e.g. the book by Krengel, Ergodic theorems. Other sources (that also go further) are [1, Sec. I.2.1] or [2, Theorem 8.8].
[1] T. Eisner, Stability of opera …
1
vote
Accepted
Values appearing with density in an ergodic system
Indeed $D(x)$ is empty for almost all $x$. It suffices to show that for all integers $b,\ell>0$, the set
$$
D_b(x,\ell) = \left\{ a \in [b,b+1) \colon \liminf_{n \to \infty} \frac{ \# \{0 \leq k < n \ …
6
votes
All two-point correlations equal to $0$, three-point correlation not $0$?
Let $\{b_n\}_{n \ge 1}$ be a sequence of independent random variables taking the values $\pm 1$ with probability $1/2$ each. Define $\{a_n\}_{n \ge 1}$ by
$a_n=b_{n-1} b_{n-2}$ if $\; n \equiv 0 \mod …
7
votes
Count of non-trivial ergodic measures of a topological dynamical system
In the most standard examples, the set of invariant ergodic measures has the cardinality of the continuum. For example, take $X=\{0,1\}^{\mathbb Z}$ equipped with the product, topology, the Borel $\si …
4
votes
Measure preserving transformation that makes two partitions independent
The property does not hold if the measure $\mu$ is atomic, so we assume that the given standard probability space $(X, \mathcal{B}, \mu)$ is nonatomic, whence it is isomorphic to he unit interval …
3
votes
Accepted
What are the hypotheses we should add for the generalizations of Furstenberg recurrence theo...
The extension you want was proved in the 1990s by Bergelson and Leibman. See [1] and also further developments in [2].
[1] Bergelson, Vitaly, and Alexander Leibman. "Polynomial extensions of van der W …
2
votes
Uniform convergence of averages for stationary ergodic process
Uniform convergence holds when $R_n$ is at most a power of $n$.
Using the tail of a Poisson variable, you can easily infer that $P(X_t>r) \le r^{-C\log \log r}$ for some $C$ that depends on the maxi …
5
votes
Accepted
Maximal ergodic inequality
For a nice introductory discussion to the maximal ergodic inequality, see
[1]. In particular, inequality (5) there is Wiener's maximal ergodic theorem. See also Lemma 15.3 in [2]. A more advanced a …
10
votes
Accepted
Can Birkhoff's ergodic theorem for integrable functions easily be deduced from Birkhoff's er...
There is a simple reduction of the Birkhoff ergodic Theorem for $L^1$ functions to the bounded case using Kakutani-Rokhlin towers, that I learned from H. Furstenberg and B. Weiss decades ago. We use …
6
votes
Accepted
Sequences similar to $\{n\alpha\}$ that are both equidistributed and truly random-like
For any $p>0$ the sequence of fractional parts $x_n=\{n^p\alpha\}$ cannot be random-like in the sense defined in the appendix. The case of integer $p$ was already discussed in the comment by Goldster …