Correction: “The set of continuous nowhere differentiable functions”
R. Daniel Mauldin · Pacific Journal of Mathematics · 1986
Let M be the set of all continuous real-valued functions defined on the closed unit interval [0,1] which do not have a finite derivative anywhere.The purpose of this note is to complete the argument that M is a coanalytic set and is not a Borel set by correcting an error in the last paragraph of an earlier paper on this topic.