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 |
Questions about abstract measure and Lebesgue integral theory. Also concerns such properties as measurability of maps and sets.
0
votes
Accepted
Product sigma-algebra: approximating elements arbitrary good using the generating sets
$\newcommand\Om\Omega\newcommand\A{\mathcal A}\newcommand\I{\mathbb I}$Your original statement is trivial: Take $B_1^i=\Omega_1$ and $B_2^i=\Omega_2$ for all $i$.
If you additionally require that $B_1 …
3
votes
Accepted
Mollifying a measure without changing its marginals
$\newcommand{\R}{\mathbb R}\newcommand{\ep}{\varepsilon}\newcommand{\tX}{\tilde X}\newcommand{\tY}{\tilde Y}\newcommand{\tpi}{\tilde\pi} $Here is how this can be done in an explicit way, at least when …
4
votes
Accepted
Is this theorem true in the case of a general measure space?
$\newcommand{\ep}{\varepsilon}\newcommand{\R}{\mathbb R}\newcommand{\N}{\mathbb N}$The answer is yes, the $f_n$'s are uniformly integrable wrt to $\mu$.
Indeed, let us follow the proof of Theorem 4.5. …
1
vote
Accepted
Integration against a measure that has an integral form
The condition
$$\int_X f\,d\rho=\int_Y\int_X f\,d\rho_y\,\mu(dy) \tag{1}$$
holds, by the definition of $\rho$, in the case when $f$ is the indicator of any $\Gamma\in\mathcal X$. By the linearity in $ …
1
vote
Approximation of a measure on $\mathbb{R}^d$
$\newcommand{\N}{\mathbb N}
\newcommand{\R}{\mathbb R}
\newcommand{\B}{\mathcal B}
\newcommand{\F}{\mathcal F}
\newcommand{\X}{\mathcal X}
\newcommand{\ep}{\epsilon}
\newcommand{\la}{\lambda}
\newcomm …
1
vote
Measurable function
The statement
Let $\phi:X\to\mathbb{R}$. When $\phi$ depends only on the coordinates
$x_k$ for $k\geq n$, this is,
$$\phi(x)=\phi(x_n,x_{n+1},x_{n+2},\ldots)\quad\mbox{for }x\in X$$ we
hav …
2
votes
Conditional distribution/independence
$\newcommand{\F}{\mathcal{F}}
\newcommand{\G}{\mathcal G}
\newcommand{\HH}{\mathcal H}$
The answer to both your questions is yes, even without assuming the existence of regular versions of conditional …
1
vote
Accepted
Properties of Random and Stopping Sets
$\newcommand{\si}{\sigma}
\newcommand{\om}{\omega}
\newcommand{\Om}{\Omega}
\newcommand{\F}{\mathcal{F}}$
The answer to your first question is negative. E.g., let $\Omega:=2^S=\mathcal P(S)$, with $\m …
1
vote
Accepted
Absolute continuity of limiting measures
Let $\nu:=\sigma$. This answer, based mainly on comments by Anthony Quas, provides a necessary and sufficient condition for $\mu\ll\nu$ (the absolute continuity of $\mu$ with respect to $\nu$) in term …
5
votes
Can we say that : $ \exists f_{\infty}\in L_{\mathbb{R}}^{1} \text{ such that: } f_n\to f_\i...
Assuming that $L^1_{\mathbb R}$ denotes the space of all classes of $\mu$-equivalent functions $f\colon E\to\mathbb R$ with $\|f\|_1=\int_E|f|\,d\mu<\infty$, the answer is yes.
Indeed, we have
$$\s …
1
vote
Disintegration associative
Disintegration is associative, in the following sense: Suppose that we have a disintegration
$$\mu(dx)=\int_Y(\mu h_1^{-1})(dy)\mu_{h_1}(y,dx)$$
of a probability measure $\mu$ with a kernel $\mu_{h_1 …
2
votes
Accepted
The properties of total variation metric
Answer to Question 3: Yes, there is such a sequence. E.g., for all $n=0,1,\dots$ and all Borel $B\subseteq[0,1]$, let
$$\mu_n(B):=\frac12\int_B(2+\sin2\pi nx)\,dx.$$
Then $\mu_n$ converges to $\mu_0$ …
1
vote
Accepted
$ \|u_k-v_k\|_2\leq \min \bigg(\inf_{n\geq k}{\|f_n1_{\{|f_n|\leq k\}}\|_2},\frac{\epsilon_{...
$\newcommand\de{\delta}$ $\newcommand\ep{\epsilon}$ $\newcommand\al{\alpha}$
Fix any natural $k$. Let $$\de_k:=\inf_{n\ge k}\|f_n 1_{\{|f_n|\le k\}}\|_2$$ and $$\eta_k:=\ep_{k-1}/(4k).$$
We have
$$ …
1
vote
Accepted
Conditional expectation values defined by expectation values
Your desired conclusion does hold without the assumption of a probability density of $\bf x$ and $\bf z$, provided that the functions $f$ and $g$ are assumed to be Borel measurable.
Indeed, let $X:= …
4
votes
Accepted
Is the set of probability measures on $\mathbb{R}$ absolutely continuous with bounded densit...
The answer is yes. Indeed, a probability measure $\mu$ over $\mathbb R$ has a density bounded by a real $K>0$ iff the cdf of $\mu$ is $K$-Lipschitz, that is, Lipschitz with the Lipschitz constant $K$. …