As title goes, without assuming continuum hypothesis, is there a subset of $\mathbb{R}$ with positive measure but not being continuum? That is,
Does there exist $A\subseteq \mathbb{R}$ such that $\mu(A)>0$ and $\aleph_0<|A|<2^{\aleph_0}$?
I believe that maybe in some system without assuming continuum hypothesis, there exists.
And by the regularity of Lebesgue measure, it suffices to deal with compact set.
There's a standard exercise in measure theory that says that if $A$ has positive measure, then $A-A$ contains an interval. It follows from this that $A$ must have the same cardinality as the reals.