Let C denote the Cantor set constructed by removing the typical open middle thirds inductively from the interval [0,1] in R.
I denote as f the characteristic function of C, i.e., f(x)=1 if x belongs to C and f(x)=0 otherwise.
I guess that the set of discontinuities of f is C (in the usual topology of R).
Could anyone show a proof of this or give a reference for one?
Many thanks!