Construct an open subset of [0,1] of arbitrary measure dense therein

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Homework Help Overview

The discussion revolves around constructing an open subset of the interval [0,1] that has a specified Lebesgue measure and is dense within that interval. The original poster seeks assistance in proving the density of this subset, which is related to the fat Cantor set.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The original poster attempts to use the fat Cantor set and is exploring the implications of its complement being dense in [0,1]. Some participants question whether the focus should be on the density of the complement of the fat Cantor set.

Discussion Status

The discussion is ongoing, with participants clarifying the nature of the sets involved and exploring different aspects of density and measure. There is a recognition of the need to prove certain properties related to the sets being discussed.

Contextual Notes

Participants are considering the constraints of the problem, including the requirement for the subset to have a specific measure and the implications of density within the interval [0,1].

benorin
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Q: Construct an open subset E of [0,1] having Lebesgue measure [itex]m(E)=\epsilon[/itex] such that [itex]0<\epsilon<1[/itex] which is dense [0,1].

A: The fat Cantor set. I need help proving it is dense in [0,1]. The usual Ternary expansion argument stuff won't work as the sets used are of length [tex]\frac{\epsilon}{3^k}[/tex] at the kth iteration. Ideas?

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Do you mean proving that [0,1]/C is dense?
 
Yes, sorry. The set at large, namely E, is the complement of the so-called fat Cantor set C in [0,1], i.e. [0,1]\C.
 
Can you find a (not necessarily open) subset of [0,1] that is dense and has measure zero?
 

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