Porous sets that are Haar null, and nowhere approximately differentiable functions
Porous sets that are Haar null, and nowhere approximately differentiable functions
We define a new notion of âHP-smallâ set $A$ which implies that $A$ is both $\sigma$-porous and Haar null in the sense of Christensen. We show that the set of all continuous functions on $[0,1]$ which have finite unilateral approximate derivative at a point $x\in [0,1]$ is HP-small, as well …