Intuition for this characterization of the exponential law











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Let $X$ and $Y$ be two real independant random variables having same distribution $mu$ with density $f$ which is positive only on $mathbb R ^+$. Let $U = min(X,Y)$ and $V = |X-Y|$. The result I was able to prove in a guided exercise is the following :




Assume that $f$ is continuous on $mathbb R ^+$. Then $U$ and $V$ are independant if and only if $mu$ is an exponential law.




I would like to have some intuition as to how to interpret this result. The only intuitive way I can think of the exponential law is that it is the only law with "no memory". How does this relate to the facts that

- for the exponential law, $U$ and $V$ are independant ?

- the exponential law is the only such law ?



Any explanation about this phenomenon are welcome.










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  • One part of the proof previously asked here. Regarding the characterization, you might have a look at this paper by T.S. Ferguson.
    – StubbornAtom
    Dec 1 at 11:17















up vote
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Let $X$ and $Y$ be two real independant random variables having same distribution $mu$ with density $f$ which is positive only on $mathbb R ^+$. Let $U = min(X,Y)$ and $V = |X-Y|$. The result I was able to prove in a guided exercise is the following :




Assume that $f$ is continuous on $mathbb R ^+$. Then $U$ and $V$ are independant if and only if $mu$ is an exponential law.




I would like to have some intuition as to how to interpret this result. The only intuitive way I can think of the exponential law is that it is the only law with "no memory". How does this relate to the facts that

- for the exponential law, $U$ and $V$ are independant ?

- the exponential law is the only such law ?



Any explanation about this phenomenon are welcome.










share|cite|improve this question






















  • One part of the proof previously asked here. Regarding the characterization, you might have a look at this paper by T.S. Ferguson.
    – StubbornAtom
    Dec 1 at 11:17













up vote
0
down vote

favorite









up vote
0
down vote

favorite











Let $X$ and $Y$ be two real independant random variables having same distribution $mu$ with density $f$ which is positive only on $mathbb R ^+$. Let $U = min(X,Y)$ and $V = |X-Y|$. The result I was able to prove in a guided exercise is the following :




Assume that $f$ is continuous on $mathbb R ^+$. Then $U$ and $V$ are independant if and only if $mu$ is an exponential law.




I would like to have some intuition as to how to interpret this result. The only intuitive way I can think of the exponential law is that it is the only law with "no memory". How does this relate to the facts that

- for the exponential law, $U$ and $V$ are independant ?

- the exponential law is the only such law ?



Any explanation about this phenomenon are welcome.










share|cite|improve this question













Let $X$ and $Y$ be two real independant random variables having same distribution $mu$ with density $f$ which is positive only on $mathbb R ^+$. Let $U = min(X,Y)$ and $V = |X-Y|$. The result I was able to prove in a guided exercise is the following :




Assume that $f$ is continuous on $mathbb R ^+$. Then $U$ and $V$ are independant if and only if $mu$ is an exponential law.




I would like to have some intuition as to how to interpret this result. The only intuitive way I can think of the exponential law is that it is the only law with "no memory". How does this relate to the facts that

- for the exponential law, $U$ and $V$ are independant ?

- the exponential law is the only such law ?



Any explanation about this phenomenon are welcome.







probability probability-distributions






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asked Nov 27 at 13:30









Suzet

2,574527




2,574527












  • One part of the proof previously asked here. Regarding the characterization, you might have a look at this paper by T.S. Ferguson.
    – StubbornAtom
    Dec 1 at 11:17


















  • One part of the proof previously asked here. Regarding the characterization, you might have a look at this paper by T.S. Ferguson.
    – StubbornAtom
    Dec 1 at 11:17
















One part of the proof previously asked here. Regarding the characterization, you might have a look at this paper by T.S. Ferguson.
– StubbornAtom
Dec 1 at 11:17




One part of the proof previously asked here. Regarding the characterization, you might have a look at this paper by T.S. Ferguson.
– StubbornAtom
Dec 1 at 11:17















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