Welcome to Randal Douc's wiki

A collaborative site on maths but not only!

User Tools

Site Tools


world:hewitt-savage

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
world:hewitt-savage [2026/02/06 13:06]
rdouc [Proof of the Hewitt-Savage 0-1 Law]
world:hewitt-savage [2026/02/06 13:06] (current)
rdouc
Line 59: Line 59:
 **Step 3: Independence and Expectation** **Step 3: Independence and Expectation**
 Introduce the intermediate quantities \(\mathsf{1}_{\bar{B}}(X_{1:​n})\) and \(\mathsf{1}_{\bar{B}}(X_{n+1:​2n})\) which are independent by independence of \((X_i)\). Then, we obtain: Introduce the intermediate quantities \(\mathsf{1}_{\bar{B}}(X_{1:​n})\) and \(\mathsf{1}_{\bar{B}}(X_{n+1:​2n})\) which are independent by independence of \((X_i)\). Then, we obtain:
-\[ 
 $$ $$
 |\mathbb{E}[\mathsf{1}_A \mathsf{1}_A] - \mathbb{E}[\mathsf{1}_A]\mathbb{E}[\mathsf{1}_A]| \leq |\mathbb{E}[\mathsf{1}_A \mathsf{1}_A] - \mathbb{E}[\mathsf{1}_{\bar{B}}(X_{1:​n})\mathsf{1}_{\bar{B}}(X_{n+1:​2n})]| + | \mathbb{E}[\mathsf{1}_{\bar{B}}(X_{1:​n})]\mathbb{E}[\mathsf{1}_{\bar{B}}(X_{n+1:​2n})]- \mathbb{E}[\mathsf{1}_A] \mathbb{E} [\mathsf{1}_A]| \leq 4\delta. |\mathbb{E}[\mathsf{1}_A \mathsf{1}_A] - \mathbb{E}[\mathsf{1}_A]\mathbb{E}[\mathsf{1}_A]| \leq |\mathbb{E}[\mathsf{1}_A \mathsf{1}_A] - \mathbb{E}[\mathsf{1}_{\bar{B}}(X_{1:​n})\mathsf{1}_{\bar{B}}(X_{n+1:​2n})]| + | \mathbb{E}[\mathsf{1}_{\bar{B}}(X_{1:​n})]\mathbb{E}[\mathsf{1}_{\bar{B}}(X_{n+1:​2n})]- \mathbb{E}[\mathsf{1}_A] \mathbb{E} [\mathsf{1}_A]| \leq 4\delta.
 $$ $$
-\] 
 Since \(\delta > 0\) is arbitrary, we conclude that: Since \(\delta > 0\) is arbitrary, we conclude that:
 \[ \[
world/hewitt-savage.1770379577.txt.gz · Last modified: 2026/02/06 13:06 by rdouc