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Jan 20, 2020 at 10:45 comment added Yaakov Baruch @Wojowu you are right. So it must be that the procedure I had in mind doesn't converge (a.e. pointwise) to a well defined set.
Jan 20, 2020 at 8:46 comment added Wojowu @YaakovBaruch Are you sure? Doesn't that contradict Lebesgue Density Theorem?
Jan 20, 2020 at 8:31 comment added Yaakov Baruch Cool. I think a similar idea (reversing subintervals of $[k/2^n,(k+1)/2^n]$ as needed, for $n\rightarrow \infty, 0\le k<n$) can also be used to produce a set $A$ with density $x$ at $x$, i.e. $\mu(A\cap[0,x])=x^2/2$.
Jan 19, 2020 at 20:05 comment added Pietro Majer In fact for all $0<x\le1$ $A\cap[0,x]$ is an $x$-dimensional set of $x$-dimensional null measure, for the same reason.
Jan 18, 2020 at 23:11 comment added Wojowu @Anixx Each $A_n$ has Hausdorff dimension below $1$, so their (1-dimensional) Lebesgue measure is zero. So $A$ has Lebesgue measure zero. You can certainly integrate functions over null sets, but the results are not too interesting...
Jan 18, 2020 at 23:06 comment added Anixx Can we Lebesgue-integrate over such set?
Jan 18, 2020 at 22:27 vote accept Anixx
Jan 18, 2020 at 22:08 history answered Christian Remling CC BY-SA 4.0