Is it true $P(cap_{n=1}^infty cup_{m=n}^infty A_m)=lim_{n to infty}P(cup_{m=n}^infty A_m)$?
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I just need some confirmation on the truth of this since I didn't see it in a textbook so far. I think it is true by continuity of probability. Am I right?
probability measure-theory
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I just need some confirmation on the truth of this since I didn't see it in a textbook so far. I think it is true by continuity of probability. Am I right?
probability measure-theory
$endgroup$
add a comment |
$begingroup$
I just need some confirmation on the truth of this since I didn't see it in a textbook so far. I think it is true by continuity of probability. Am I right?
probability measure-theory
$endgroup$
I just need some confirmation on the truth of this since I didn't see it in a textbook so far. I think it is true by continuity of probability. Am I right?
probability measure-theory
probability measure-theory
asked Dec 6 '18 at 3:16
Daniel LiDaniel Li
664413
664413
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2 Answers
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For each $n in mathbb N$, let $B_n=bigcup_{m=n}^infty A_m $. Clearly for each $n in mathbb N$ we have $B_n supseteq B_{n+1}$, and so ${B_n}_{n=1}^infty$ is a decreasing sequence of sets. Moreover, $P(B_1)<infty$ as a probability measure is finite. Therefore, $$Pleft(bigcap_{n=1}^infty B_nright)=lim_{nto infty} P(B_n)$$ by the continuity from above property of a measure which is $(3')$ here.
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Let $B_n:=bigcup_{mge n}A_m$. Then $B_{n+1}subseteq B_n$ and by continuity from above,
$$
mathsf{P}left(bigcap_{nge 1} B_nright)=lim_{ntoinfty} mathsf{P}(B_n).
$$
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Your Answer
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
For each $n in mathbb N$, let $B_n=bigcup_{m=n}^infty A_m $. Clearly for each $n in mathbb N$ we have $B_n supseteq B_{n+1}$, and so ${B_n}_{n=1}^infty$ is a decreasing sequence of sets. Moreover, $P(B_1)<infty$ as a probability measure is finite. Therefore, $$Pleft(bigcap_{n=1}^infty B_nright)=lim_{nto infty} P(B_n)$$ by the continuity from above property of a measure which is $(3')$ here.
$endgroup$
add a comment |
$begingroup$
For each $n in mathbb N$, let $B_n=bigcup_{m=n}^infty A_m $. Clearly for each $n in mathbb N$ we have $B_n supseteq B_{n+1}$, and so ${B_n}_{n=1}^infty$ is a decreasing sequence of sets. Moreover, $P(B_1)<infty$ as a probability measure is finite. Therefore, $$Pleft(bigcap_{n=1}^infty B_nright)=lim_{nto infty} P(B_n)$$ by the continuity from above property of a measure which is $(3')$ here.
$endgroup$
add a comment |
$begingroup$
For each $n in mathbb N$, let $B_n=bigcup_{m=n}^infty A_m $. Clearly for each $n in mathbb N$ we have $B_n supseteq B_{n+1}$, and so ${B_n}_{n=1}^infty$ is a decreasing sequence of sets. Moreover, $P(B_1)<infty$ as a probability measure is finite. Therefore, $$Pleft(bigcap_{n=1}^infty B_nright)=lim_{nto infty} P(B_n)$$ by the continuity from above property of a measure which is $(3')$ here.
$endgroup$
For each $n in mathbb N$, let $B_n=bigcup_{m=n}^infty A_m $. Clearly for each $n in mathbb N$ we have $B_n supseteq B_{n+1}$, and so ${B_n}_{n=1}^infty$ is a decreasing sequence of sets. Moreover, $P(B_1)<infty$ as a probability measure is finite. Therefore, $$Pleft(bigcap_{n=1}^infty B_nright)=lim_{nto infty} P(B_n)$$ by the continuity from above property of a measure which is $(3')$ here.
edited Dec 6 '18 at 4:05
answered Dec 6 '18 at 3:38
Matt A PeltoMatt A Pelto
2,537620
2,537620
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$begingroup$
Let $B_n:=bigcup_{mge n}A_m$. Then $B_{n+1}subseteq B_n$ and by continuity from above,
$$
mathsf{P}left(bigcap_{nge 1} B_nright)=lim_{ntoinfty} mathsf{P}(B_n).
$$
$endgroup$
add a comment |
$begingroup$
Let $B_n:=bigcup_{mge n}A_m$. Then $B_{n+1}subseteq B_n$ and by continuity from above,
$$
mathsf{P}left(bigcap_{nge 1} B_nright)=lim_{ntoinfty} mathsf{P}(B_n).
$$
$endgroup$
add a comment |
$begingroup$
Let $B_n:=bigcup_{mge n}A_m$. Then $B_{n+1}subseteq B_n$ and by continuity from above,
$$
mathsf{P}left(bigcap_{nge 1} B_nright)=lim_{ntoinfty} mathsf{P}(B_n).
$$
$endgroup$
Let $B_n:=bigcup_{mge n}A_m$. Then $B_{n+1}subseteq B_n$ and by continuity from above,
$$
mathsf{P}left(bigcap_{nge 1} B_nright)=lim_{ntoinfty} mathsf{P}(B_n).
$$
edited Dec 6 '18 at 4:00
answered Dec 6 '18 at 3:32
d.k.o.d.k.o.
9,145628
9,145628
add a comment |
add a comment |
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